User Manual: 3rd Generation EPS Range No Inhibits Clyde Space Manual 1335 Rev D
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User Manual: 3rd Generation EPS Range - No Inhibits Document No.: USM-1335 Issue: D Date: 11 Oct 2017 Name Date Alec Wright 5 May 2016 Updated Colin Waddell 2 Aug 2017 Approved Thomas Parry 11 Oct 2017 Author Signed Clyde Space Ltd. SkyPark 5 45 Finnieston Street Glasgow G3 8JU, U.K. t: + 44 (0) 141 946 4440 e: enquiries@clyde.space w: www.clyde.space Registered in Scotland No. SC285287 at 123 St Vincent Street Glasgow G2 5EA SOLUTIONS FOR A NEW AGE IN SPACE USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Page: 2 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Document Control Issue Date Section Description of Change A 05/04/2016 All Information from USM-2501309, USM-25-01311 RevF, USM-01-01317 RevE, USM-2502452 RevC, USM-01-02453 RevB combined to create family user manual B 13/06/2017 2 Updating the table in section 3 Update figure 3.1 9 Adding section for 5V USB Charge 9.8 Updated the trip current for switches 3 and 4 in Table 9-1. C 20/06/2017 11.4 Reason for Change DCR039 DCR044 Updated the telemetry equations (ISW3, ISW4, VBCR1, VBCR2, VBCR4, VBCR5, VBCR6, VBCR7, VBCR8 and VBCR9) in tables 11-7, 11-9 & 11-10) D 2/08/2017 11.2 11.3 Get Version+Revision is now split into two separate commands for devices running firmware version 18-02012 Rev E + 18-2013 Rev C and above DCR73 Revision Control Product Part Number Notes 3rd Generation EPS (1UB) No Inhibits 25-02451 N/A 3rd Generation EPS (3UA) No Inhibits 25-02452 H 3rd Generation EPS (XUA) No Inhibits 01-02453 N/A Acronyms and Abbreviations 1U 1 Unit (Cubesat standard size) 2s1p Battery configuration – 2 cells in series, 1 string in parallel 2s2p Battery configuration – 2 cells in series, 2 string in parallel 2s3p Battery configuration – 2 cells in series, 3 string in parallel 3U 3 Unit (Cubesat standard size) ADC Analogue to Digital Converter Ah Ampere Hour AIT Assembly, Integration and Testing AMUX Analogue Multiplexer BCR Battery Charge Regulator DoD Depth of Discharge EoC End of Charge EPS Electrical Power System SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 ESD Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 3 of 60 Electro Static Discharge FleXU/XU FleXible Unit (suitable for various satellite configurations) Isc Short Circuit Current Kbits-1 Kilobits per second MPPT Maximum Power Point Tracker PCM Power Conditioning Module PDM Power Distribution Module rh Relative Humidity TLM Telemetry USB Universal Serial Bus Voc Open Circuit Voltage Wh Watt Hour Related Documents No. Document Name Doc Ref. RD-1 3rd Generation CubeSat Battery Family Rev B User Manual USM-1192 RD-2 CubeSat Design Specification CubeSat Design Specification Rev. 12 RD-3 NASA General Verification Standard GSFC-STD-7000 April 2005 RD-4 CubeSat Kit Manual UM-3 RD-5 Solar Panel User Document Power System Design and Performance on the World’s Most Advanced In-Orbit Nanosatellite TBC RD-6 Warning Environmental As named Risk Ensure headers H1 and H2 are correctly aligned before mating boards If misaligned, battery positive can short to ground, causing failure of the battery and EPS Ensure switching configuration is implemented correctly before applying power to EPS If power is applied with incorrect switch configuration, the output of the BCR can be blown, causing failure of the EPS Observe ESD precautions at all times The EPS is a static sensitive system. Failure to observe ESD precautions can result in failure of the EPS. Ensure not to exceed the maximum stated limits Exceeding any of the stated maximum limits can result in failure of the EPS Ensure batteries are fully isolated during storage If not fully isolated (by switch configuration or separation) the battery may over-discharge, resulting in failure of the battery No connection should be made to H2.35-36 or H2.4144 These pins are used to connect the battery to the EPS. Any connections to the unregulated battery bus should be made to pins H2.45-46 H1 and H2 pins should not be shorted at any time These headers have exposed live pins which should not be shorted at any time. Particular care should be taken regarding the surfaces these are placed on. SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 Issue: D User Manual: 3rd Generation EPS Range - No Inhibits Date: 11/10/2017 SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION Page: 4 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 Issue: D User Manual: 3rd Generation EPS Range - No Inhibits Date: 11/10/2017 Page: 5 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Table of Contents 1. Introduction .......................................................................................................................... 7 1.1 Additional Information Available Online ............................................................................................ 7 1.2 Continuous Improvement .................................................................................................................. 7 1.3 Document Revisions........................................................................................................................... 7 2. Overview ............................................................................................................................... 8 2.1 3. Applicable Products ........................................................................................................................... 8 Maximum Ratings ................................................................................................................. 9 3.1 BCR Safe Operating Area .................................................................................................................. 10 4. Electrical Characteristics ..................................................................................................... 11 5. Handling and storage .......................................................................................................... 12 5.1 Electro Static Discharge (ESD) Protection ........................................................................................ 12 5.2 General Handling ............................................................................................................................. 12 5.3 Shipping and Storage ....................................................................................................................... 12 6. Materials and Processes ..................................................................................................... 13 6.1 Materials Used ................................................................................................................................. 13 6.2 Processes and Procedures ............................................................................................................... 13 7. System Description ............................................................................................................. 14 7.1 System Overview ............................................................................................................................. 17 7.2 Autonomy and Redundancy ............................................................................................................. 18 7.3 Quiescent Power Consumption ....................................................................................................... 18 7.4 Mass and Mechanical Configuration ................................................................................................ 18 8. Interfacing ........................................................................................................................... 20 8.1 Solar Array Connection .................................................................................................................... 22 8.2 Solar Array Harness .......................................................................................................................... 24 8.3 Temperature Sensing Interface ........................................................................................................ 24 8.4 Sun Detector Interface ..................................................................................................................... 24 8.5 Non-Clyde Space Solar Arrays .......................................................................................................... 24 8.6 CubeSat Kit Compatible Headers ..................................................................................................... 24 8.7 Cubesat Kit Header Pin Out .............................................................................................................. 26 8.8 Flight Switches ................................................................................................................................. 27 8.9 Battery connection........................................................................................................................... 27 9. Technical description .......................................................................................................... 28 9.1 Charge Method ................................................................................................................................ 28 9.2 BCR Power Stage Overview .............................................................................................................. 29 9.3 MPPT ................................................................................................................................................ 29 9.4 5V USB Charge ................................................................................................................................. 30 9.5 5V and 3.3V PCMs with Latching Current Limiter ............................................................................ 30 SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 Issue: D User Manual: 3rd Generation EPS Range - No Inhibits Date: 11/10/2017 Page: 6 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK 9.6 12V PCM with Latching Current Limiter ........................................................................................... 32 9.7 BatV PCM with Latching Current Limiter ......................................................................................... 32 9.8 PDMs with Latching Current Limiter ................................................................................................ 32 10. General Protection ............................................................................................................. 35 10.1 Over-Current Bus Protection (LCL) ................................................................................................... 35 10.2 Battery Under-Voltage Protection ................................................................................................... 36 11. Telemetry and Telecommand ............................................................................................. 37 11.1 Communications .............................................................................................................................. 37 11.2 List of Available Commands ............................................................................................................. 39 11.3 Housekeeping and Status Commands .............................................................................................. 40 11.4 Telemetry ......................................................................................................................................... 43 11.5 Watchdogs and Reset Counters ....................................................................................................... 48 11.6 PDM Control .................................................................................................................................... 50 11.7 PDM Timers...................................................................................................................................... 53 11.8 PCM Control ..................................................................................................................................... 55 12. Test ..................................................................................................................................... 55 12.1 Required Equipment ........................................................................................................................ 55 12.2 Standalone Test Setup ..................................................................................................................... 57 12.3 Testing with Clyde Space Battery ..................................................................................................... 58 13. 13.1 Compatible Systems ........................................................................................................... 59 Compatible Batteries ....................................................................................................................... 60 SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Page: 7 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK 1. INTRODUCTION This document provides information on the features, operation, handling and storage of the 25-02451, 25-02452 and 01-02453 EPS products, designed to integrate with a suitable battery and solar arrays to form a complete power system for use on a CubeSat. Figure 1-1 System Diagram 1.1 Additional Information Available Online Additional information on CubeSats and Clyde Space Systems can be found at www.clyde.space. You will need to log in to our website to access certain documents. 1.2 Continuous Improvement At Clyde Space we are continuously improving our processes and products. We aim to provide full visibility of the changes and updates that we make, and information of these changes can be found by logging in to our website: www.clyde.space 1.3 Document Revisions In addition to hardware and software updates, we also update make regular updates to our documentation and online information. SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 8 of 60 2. OVERVIEW The Clyde Space 3rd Generation (3G) EPS range is the latest incarnation of Clyde Space's highly successful CubeSat power system range, which has powered almost half of all CubeSat missions to date. Our 3G range is our most capable and compact CubeSat EPS range to date, providing robust, high-performance mission capability. The main features include: • • • • • • 3.3V, 5V, and 12V regulated power buses Unregulated battery bus 10 Latching Current Limit (LCL) power distribution modules Maximum Power-Point Tracking (MPPT) Battery Charge Regulators (BCRs) Over-current, over- and under-voltage protection Watchdog timer As a result of the new features added in the 3rd Generation there is a requirement to alter the interfaces to the main CubeSat Kit header. Further detail on the new features and interfaces can be found in this user manual. Clyde Space is a world-leading provider of spacecraft power systems, from CubeSats through to Small GEO satellites. Since establishment in 2006 Clyde Space has provided thousands of spacecraft subsystems, and has grown to be a leading provider of nanosatellite spacecraft platforms as well. Our heritage and experience mean you can be sure a Clyde Space component comes with performance and quality assured. 2.1 Applicable Products This user manual describes three variants of the 3rd Generation No Inhibits EPS. The differences between these variants are summarised below 3G 1U EPS (25-02451) 3G 3U EPS (25-02452) 3G FlexU EPS (01-02453) Intended Use 1U CubeSats 2U and 3U CubeSats with body panels 3U CubeSats with deployable panels, and larger nanosatellites Number of SEPIC BCRs 4 BCRs 1 BCR 1 BCR Number of Buck BCRs None 2 BCRs 8 BCRs SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 9 of 60 3. MAXIMUM RATINGS Stresses beyond those listed under maximum ratings may cause permanent damage to the EPS. Operation of the EPS at conditions beyond those indicated is not recommended. Exposure to absolute maximum ratings for extended periods may affect EPS reliability. De-rating of power critical components is in accordance with ECSS guidelines. OVER OPERATING TEMPERATURE RANGE (UNLESS OTHERWISE STATED) Input Voltage(2) Input Current Value Unit Buck BCRs 30 V SEPIC BCRs 9.5 V Battery 8.3 V Value Unit Buck BCRs SEPIC BCRs Refer to Section 3.1 Value Unit Operating Temperature -40 to 85 °C Storage Temperature -50 to 100 °C Vacuum 10-5 torr Radiation Tolerance 10 kRad Vibration To [RD-3] Table 3-1 Max Ratings of the EPS products SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 10 of 60 3.1 BCR Safe Operating Area 1.2 Solar Array Current/A 1 0.8 0.6 Single Channel Dual Channel 0.4 0.2 0 0 5 10 15 20 25 30 35 Solar Array Voltage/V Figure 3-1 Safe Operating Range for Buck BCRs 1.2 Solar Array Current/A 1 0.8 0.6 Single Channel Dual Channel 0.4 0.2 0 0 2 4 6 8 10 Solar Array Voltage/V Figure 3-2 Safe Operating Range for SEPIC BCRs at TBRD=60°C The safe operating ranges of the BCRs are shown above. Single Channel refers to the maximum current which can be applied to a single pin (e.g. SA1.1). Dual Channel refers to the limit on the sum of the currents which can be applied to two pins connecting to the same BCR (e.g. SA1A.1 and SA1B.1 or SA5.1 and SA5.5). For BCR allocations, see Section 9.2. It is important to ensure that the limits of the BCRs given above are not exceeded either at open circuit or at maximum power point. SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 11 of 60 4. ELECTRICAL CHARACTERISTICS Description Conditions Min Typical Max Unit Input Voltage 7.41 -- 30 V End of Charge Voltage 8.165 8.265 8.365 V 150 175 200 kHz 85% 90% 92% Min Typical Max Unit Input Voltage 3.0 -- 9.5 V End of Charge Voltage 8.165 8.265 8.365 V Operating Frequency 145 170 200 kHz Buck BCRs Switching Frequency Efficiency @16.5V Load input, SEPIC BCRs Conditions Full Efficiency @6V input, Full Load 77% 79% 80% Unregulated Battery Bus Conditions Min Typical Max Output Voltage -- Battery Voltage -- LCL Trip Point 4.55 4.7 4.85 98.5% 99% 99.5% Efficiency @8.26V Load input, 5V Bus Conditions Unit A Full Min Typical Max Unit Output Voltage 4.95 5 5.05 V LCL Trip Point 4.4 4.5 4.6 A Operating Frequency 400 480 560 kHz Efficiency @5V, Full Load -- 93% -- 3.3V Bus Conditions Min Typical Max Unit Output Voltage 3.267 3.3 3.333 V LCL Trip Point 4.4 4.5 4.6 A Operating Frequency 400 480 560 kHz Efficiency @3.3V, Full Load -- 90% -- 12V Bus Conditions Min Typical Max Unit Output Voltage 11.88 12 12.12 V LCL Trip Point 1.4 1.5 1.6 A Operating Frequency 670 800 930 kHz -- 92% -- Communications Min Typical Max Protocol -- I2C -- Transmission speed -- 100 -- Bus voltage 3.26V 3.3V 3.33V Node address -- 0x2B -- Address scheme -- 7 bit -- -- 27MHz -- Efficiency @3.3V input, Full Load Node operating frequency Quiescent Operation Conditions Flight Configuration of Activation Switches Power Draw Max 25-02451: 0.2 25-02452: 0.2 01-02453: 0.4 Unit kbits-1 Unit W Table 4-1 Performance Characteristics of the EPS 1 If VMPP is below 9.4V, the converter will deviate from the maximum power point during taper charge and will charge less efficiently SOLUTIONS FOR A NEW AGE IN SPACE www.clyde.space PROPRIETARY & CONFIDENTIAL INFORMATION Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 Issue: D User Manual: 3rd Generation EPS Range - No Inhibits Date: 11/10/2017 Page: 12 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK 5. HANDLING AND STORAGE The EPS requires specific guidelines to be observed for handling, transportation and storage. These are stated below. Failure to follow these guidelines may result in damage to the units or degradation in performance. 5.1 Electro Static Discharge (ESD) Protection The EPS incorporates static sensitive devices and care should be taken during handling. Do not touch the EPS without proper electrostatic protection in place. All handling of the system should be done in a static dissipative environment. 5.2 General Handling The EPS is robust and designed to withstand flight conditions. However, care must be taken when handling the device. Do not drop the device as this can damage the EPS. There are live connections between the battery systems and the EPS on the CubeSat Kit headers. All metal objects (including probes) should be kept clear of these headers. Gloves should be worn when handling all flight hardware. Flight hardware will be delivered conformally coated, and should only be removed from packaging in a class 100000 (or better) clean room environment. 5.3 Shipping and Storage The devices are shipped in anti-static packaging, enclosed in a hard protective case. This case should be used for storage. All hardware should be stored in anti-static containers at temperatures between 20°C and 40°C and in a humidity-controlled environment of 40-60%rh. The shelf-life of this product is estimated at 5 years when stored appropriately. SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 13 of 60 6. MATERIALS AND PROCESSES 6.1 Materials Used Material Manufacturer %TML %CVCM %WVR Application Applicable Products Araldite 2014 Epoxy Huntsman 0.97 0.05 0.33 Adhesive fixing All 1B31 Acrylic Humiseal 3.89 0.11 0.09 Conformal Coating All DC 6-1104 Dow Corning 0.17 0.02 0.06 Adhesive fixing on modifications All Stycast 2850 Emerson & Cuming 0.25 0.01 0.05 Adhesive fixing All PCB material FR4 0.62 0 0.1 Note: worst case on NASA out-gassing list All Solder Resist CARAPACE EMP110 or XV501T-4 0.95 or 0.995 0.02 Or 0.001 0.31 - All Solder Sn62 or Sn63 (Tin/Lead) - - - - All Flux Alpha Rosin Flux, RF800, ROL 0 - - - Low activity flux to avoid corrosion All 300 Series Stainless Steel Pemnet - - - PEMs 01-02453 A4 Stainless Steel (316L) PTS-UK - - - M3 Fasteners 01-02453 Table 6-1 Materials List Part Used Manufacturer Contact Insulator Type Use Required mating Connector Applicable Products DF13-6P1.25DSA(50) Hirose Gold Plated Polyamide PTH Programming Header – not for customer use DF13-6S-1.25C and DF13-2630SCFA(04) All DF13-5P1.25DSA(50) Hirose Gold Plated Polyamide PTH Solar Array Connectors DF13-5S-1.25C and DF13-2630SCFA(04) All ESQ-12639-G-D Samtec Gold Plated Black Glass Filled Polyester PTH CubeSat Kit Compatible Headers ESQ-126 range All FTSH-11001-F-DV Samtec Gold Plated Beryllium Copper Black Liquid Crystal Polymer SMT Expansion Header for daughterboard connection TFM-110-22-L-D-A 25-02451 SFM-11002-L-D-A Samtec Gold Plated Beryllium Copper Black Liquid Crystal Polymer SMT Expansion Header for daughterboard connection TFM-110-22-L-D-A 25-02452, 01-02453 TFM-11022-L-D-A Samtec Gold Plated Beryllium Copper Black Liquid Crystal Polymer SMT Daughterboard to motherboard connection header SFM-110-02-L-D-A 01-02453 DF13-8P1.25DSA(50) Hirose Gold Plated Polyamide PTH Solar Array Connectors (Daughter Board) DF13-8s-1.25C and DF13-2630SCFA(04) 01-02453 Table 6-2 Connector Headers 6.2 Processes and Procedures All assembly is inspected to ESA Workmanship Standards; ECSS-Q-ST-70-08C and ECSS-Q-ST-70-38C. SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 Issue: D User Manual: 3rd Generation EPS Range - No Inhibits Date: 11/10/2017 Page: 14 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK 7. SYSTEM DESCRIPTION The Clyde Space EPS products are optimised for Low Earth Orbit (LEO). They are designed for integration with spacecraft that have six body mounted solar panels or fewer (i.e. one on each spacecraft facet), or potentially other configurations involving deployable panels. The EPS can accommodate various solar panel configurations, and has been designed to be versatile; please consult our support team if you have specific requirements for connecting the EPS to your spacecraft. The Clyde Space EPS connects to the solar panels via a number of independent Battery Charge Regulators (BCRs). These are connected with panels on opposing faces of the satellite connected to the same BCR. Additional BCRs (not applicable to 25-02452) allow deployable panels to be used. In this configuration only one panel per pair can be directly illuminated at any given time, with the second panel providing a limited amount of energy due to albedo illumination. Each of the BCRs has an inbuilt Maximum Power Point Tracker (MPPT). This MPPT will track the dominant panel of the connected pair (the directly illuminated panel). The output of the BCRs are then connected together and supply charge to the battery, Power Conditioning Modules (PCMs) and Power Distribution Modules (PDMs). The PCM network has an unregulated Battery Voltage Bus, a regulated 5V supply, a regulated 3.3V supply and a regulated 12V supply, each with a separate Latching Current Limiter (LCL) with automatic retry. In addition to the main buses there are 10 commandable PDMs – 2x12V, 2xBATV, 3x5V and 3x3.3V. The EPS also has multiple inbuilt protection methods to ensure safe operation during the mission and a full range of EPS telemetry via the I2C network. These are discussed in detail in Sections 10 and 11. SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 15 of 60 SA3A Array SA2A Array SA1B Array SA1A Array SA2B Array SA3B Array Figure 7-1 Typical Array Configuration for 25-02452 with Example Allocations (for 01-02453, deployed panels can additionally interface to BCRs 4-9) SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 Issue: D User Manual: 3rd Generation EPS Range - No Inhibits Date: 11/10/2017 Page: 16 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Figure 7-2 Typical Array Configuration for 25-02451 with Example Allocations. Fourth BCR interface not shown in image. SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 Issue: D User Manual: 3rd Generation EPS Range - No Inhibits Date: 11/10/2017 Page: 17 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK 7.1 System Overview Figure 7-3 Functional Diagram SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 Issue: D User Manual: 3rd Generation EPS Range - No Inhibits Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 18 of 60 7.2 Autonomy and Redundancy All BCR power stages feature full system autonomy, operating solely from the solar array input and not requiring any power from the battery systems. This feature offers graceful degradation of the system as none of the BCRs depend on any other circuitry to operate correctly. Failure of all strings of the battery (any of the Clyde Space battery range) will not damage the BCRs but, due to the MPPT, will result in an intermittent interruption on all power buses (approximately every 2.5 seconds). The rest of the power system is a robustly designed single string. 7.3 Quiescent Power Consumption All power system efficiencies detailed (for BCRs and PCMs) take into consideration the associated low level control electronics. As such, these numbers are not included in the quiescent power consumption figures. The quiescent current draw covers the power required to run the TTC node, PDMs and other monitoring and safety features of the EPS, and values are given in Table 4-1. 7.4 Mass and Mechanical Configuration The system is contained on a single PC/104 size card, compatible with the Cubesat Kit bus. The 0102453 FlexU EPS also includes a daughterboard. The 25-02451 1U EPS can be used as the motherboard for a CubeSat power system with an integrated battery. This will be documented in the battery user manual [RD-1]. The 25-02452 and 01-02453 EPS products are expected to be used with a standalone battery. The masses of the EPS products are specified in Table 7-1 and dimensioned drawings are given in Figure 7-4 through Figure 7-6. Part number Min Typical Max Unit 25-02451 84 86 88 g 25-02452 84 86 88 g 01-02453 145 148 150 g Table 7-1 Mass of EPS Products Figure 7-4 Dimensioned Drawing of 25-02451 1UB EPS SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 Issue: D User Manual: 3rd Generation EPS Range - No Inhibits Date: 11/10/2017 Page: 19 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Figure 7-5 Dimensioned Drawing of 25-02452 3UA EPS Figure 7-6 Dimensioned Drawing of 01-02453 XUA EPS SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Page: 20 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK 8. INTERFACING The connector interfaces of the EPS are outlined in Figure 8-1, including the solar array inputs, output of the power buses and communication to the I2C node. In the following section, it is assumed that the EPS will be integrated with a Clyde Space Battery. Figure 8-1 Connector Location Diagram for 25-02451 1UB EPS Figure 8-2 Connector Location Diagram for 25-02452 and 01-02453 Motherboard SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Page: 21 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Figure 8-3 Additional Daughterboard Connections for 01-02453 XUA EPS The connector positions and functions are described in Table 8-1. Connector Function Location Applicable Products SA1A Solar Array connector, BCR1 channel A Motherboard All SA1B Solar Array connector, BCR1 channel B Motherboard All SA2A Solar Array connector, BCR2 channel A Motherboard All SA2B Solar Array connector, BCR2 channel B Motherboard All SA3A Solar Array connector, BCR3 channel A Motherboard All SA3B Solar Array connector, BCR3 channel B Motherboard All SA4A Solar Array connector, BCR4 channel A Motherboard 25-02451 SA4B Solar Array connector, BCR4 channel B Motherboard 25-02451 SA4 Solar Array connector, BCR4 both channels Daughterboard 01-02453 SA5 Solar Array connector, BCR5 both channels Daughterboard 01-02453 SA6 Solar Array connector, BCR6 both channels Daughterboard 01-02453 SA7 Solar Array connector, BCR7 both channels Daughterboard 01-02453 SA8 Solar Array connector, BCR8 both channels Daughterboard 01-02453 SA9 Solar Array connector, BCR9 both channels Daughterboard 01-02453 J1_IC1 Programming header – Clyde Space use only Motherboard All H1 CubeSat Kit bus compatible Header 1 Motherboard All H2 CubeSat Kit bus compatible Header 2 Motherboard All Table 8-1 Connector functions SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 Issue: D User Manual: 3rd Generation EPS Range - No Inhibits Date: 11/10/2017 Page: 22 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK 8.1 Solar Array Connection The EPS motherboard has eight (25-02451) or six (25-02452, 01-02453) connectors for the attachment of solar arrays. The EPS daughterboard (01-02453 only) has a further six such connectors. This interface accommodates inputs from the arrays with temperature and sun detector telemetry for each. HIROSE DP13-5P-1.25DSA(50) connector sockets are used for motherboard solar array inputs. Inputs labelled as A and B are always connected to the BCR in parallel with one another. An example configuration is shown in Figure 8-4. HIROSE DP13-8P-1.25DSA(50) connector sockets are used for daughterboard solar array inputs. An example configuration is shown in Figure 8-5. All arrays which are connected in parallel should have the same number of cells. Figure 8-4 Example Solar Array Configuration SA1-3 and (25-02451 only) SA4 SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Page: 23 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Figure 8-5 Example Solar Array Configuration SA4-9 (01-02453 only) Pin Use Notes 1 Array Power Connection to positive of solar cell string 2 Array Return Negative of solar cell string – connected to ground within the EPS 3 Temperature Telemetry Telemetry 4 Ground Line Ground connection for Sensors 5 Sun Detector Telemetry Telemetry Table 8-2 Pinout for motherboard solar array connectors Pin Use Notes 1 Array A Power Connection to positive of solar cell string 2 Ground Negative of solar cell string and ground connection for sensors – connected to ground within the EPS 3 Array A Temperature Telemetry Telemetry 4 Array A Sun Detector Telemetry Telemetry 5 Array B Power Connection to positive of solar cell string 6 Ground Negative of solar cell string and ground connection for sensors – connected to ground within the EPS 7 Array B Temperature Telemetry Telemetry 8 Array B Sun Detector Telemetry Telemetry Table 8-3 Pinout for daughterboard solar array connectors SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 Issue: D User Manual: 3rd Generation EPS Range - No Inhibits Date: 11/10/2017 Page: 24 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK 8.2 Solar Array Harness Clyde Space supply harnesses (sold separately) to connect the solar panels to the EPS Motherboard, comprising one Hirose DF13-5S-1.25C connected at the panel and one connector at the other connected at the EPS. Similarly, harnesses to connect the solar panels to the EPS Daughterboard (0102453 only) comprise one Hirose DF13-8S-1.25C connected at the panel and one connector at the other connected at the EPS. 8.3 Temperature Sensing Interface A temperature sensor is included on each Clyde Space solar panel and can be connected to the EPS to provide panel temperature telemetry. The output from the sensor is then passed to the telemetry system via on board signal conditioning. The formula for calculating solar array temperature from ADC counts can be found in Section 11.4. 8.4 Sun Detector Interface A photodiode-based coarse sun detector is included on each Clyde Space solar panel and can be connected to each BCR channel to provide panel illumination telemetry. On-board signal conditioning converts this signal to an ADC count which can be translated into an illumination level using the equations in section 11.4. 8.5 Non-Clyde Space Solar Arrays When connecting non-Clyde Space solar arrays care must be taken with the polarity. Cells used should be of triple junction type. If other manufacturer’s panels are to be interfaced, please contact Clyde Space. 8.6 CubeSat Kit Compatible Headers Connections from the EPS to the bus of the satellite are made via the CubeSat Kit compatible headers H1 and H2, as shown in Figure 8-6. SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 Issue: D User Manual: 3rd Generation EPS Range - No Inhibits Date: 11/10/2017 Page: 25 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Figure 8-6 CubeSat Kit Header Schematic SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 26 of 60 8.7 Cubesat Kit Header Pin Out HEADER 1 Use - Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Name NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC 32 5VUSB_CHG 5V USB Charge 33 34 35 36 37 38 39 40 41 42 43 44 NC NC NC NC NC NC NC NC I2C_DATA NC I2C_CLK NC 45 HEADER 2 Use PDM 1 Output Ground PDM 2 Output PDM 3 Output PDM 4 Output PDM 5 Output Ground PDM 6 Output PDM 7 Output Ground PDM 8 Output PDM 9 Output PDM 10 Output Ground Ground 12V Bus 12V Bus 5V Bus 5V Bus 3.3V Bus 3.3V Bus Ground Ground - Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Name NC NC NC NC NC NC NC SW1 GND SW2 SW3 SW4 SW5 GND SW6 SW7 GND SW8 SW9 SW10 GND GND 12VBUS 12VBUS 5VBUS 5VBUS 3V3BUS 3V3BUS GND GND NC 32 GND Ground System Ground I2C Data I2C Clock - Notes Battery Top up Charge - Notes 12V PDM System Ground 12V PDM BAT PDM BAT PDM 5V PDM System Ground 5V PDM 5V PDM System Ground 3V3 PDM 3V3 PDM 3V3 PDM System Ground System Ground Power Bus Power Bus Power Bus Power Bus Power Bus Power Bus System Ground System Ground - 33 34 35 36 37 38 39 40 41 42 43 44 Reserved Reserved PCM_IN PCM_IN Reserved Reserved Reserved Reserved BCR_OUT BCR_OUT BCR_OUT BCR_OUT Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved NC - - 45 BatVBUS 46 NC - - 46 BatVBUS 47 48 49 50 51 52 NC NC NC NC NC NC - - 47 48 49 50 51 52 GND GND NC NC NC NC Do not use Do not use PCM Input PCM Input Do not use Do not use Do not use Do not use BCR Output BCR Output BCR Output BCR Output Unregulated Battery Bus Unregulated Battery Bus Ground Ground - Power Bus Power Bus System Ground System Ground - Table 8-4 Pin Descriptions for Header H1 and H2 SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 Issue: D User Manual: 3rd Generation EPS Range - No Inhibits Date: 11/10/2017 Page: 27 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK 8.8 Flight Switches The Flight Switches provide a method of isolating the BCRs and battery from the satellite power buses during storage, transportation and launch. This EPS does not have flight switches populated as it is designed to be used with a compatible battery which contains the inhibits. Refer to User manual: 3rd Generation CubeSat Battery Family [RD-1] for information on flight switches, Sections 10.1 Protection Overview and 10.7 Inhibit Operation. 8.9 Battery connection Connection of the battery systems on the EPS is via the CubeSat kit bus or via an integrated battery (25-02451 only). Ensure that the pins are aligned, and located in the correct position, as any offset can cause the battery to be shorted to ground, leading to catastrophic failure of the battery and damage to the EPS. It is also important that the EPS is only used with compatible battery products; see Section 13.1 for information. Failure to observe these precautions will result in the voiding of any warranty. When a battery board is connected to the CubeSat Kit header and the battery inhibits are not activated, there are live unprotected battery pins accessible (H2.35-36 and H2.41-44). These pins should not be routed to any connections other than the Clyde Space EPS, otherwise all EPS-based protections will be bypassed and significant battery damage can be sustained. SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Page: 28 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK 9. TECHNICAL DESCRIPTION This section gives a complete overview of the operational modes of the EPS. It is assumed that a complete Clyde Space power system (EPS, Batteries and Solar panels) is in operation for the following sections. 9.1 Charge Method The BCR charging system has two modes of operation: Maximum Power Point Tracking (MPPT) mode and End of Charge (EoC) mode. These modes are governed by the state of charge of the battery. MPPT Mode If the battery voltage is below the EoC voltage the system is in MPPT mode. This is based on constant current charge method, operating at the maximum power point of the solar panel for maximum power transfer. EoC Mode Once the EoC voltage has been reached, the BCR changes to EoC mode, which is a constant voltage charging regime. The EoC voltage is held constant and a tapering current from the panels is supplied to top up the battery until at full capacity. In EoC mode the MPPT circuitry moves the solar array operation point away from the maximum power point of the array, drawing only the required power from the panels. The excess power is left on the arrays as heat, which is transferred to the structure via the array’s thermal dissipation methods incorporated in Clyde Space panels. The operation of these two modes can be seen in Figure 9-1. end of charge voltage Figure 9-1 Tapered charging method SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 29 of 60 The application of constant current/constant voltage charge method on a spacecraft is described in more detail in RD-6. In this document, there is on-orbit data showing the operation and how the current fluctuates with changing illumination conditions and orientation of the spacecraft with respect to the Sun. 9.2 BCR Power Stage Overview The EPS has several separate, independent BCRs, each designed to interface to two parallel solar arrays on opposing faces of the satellite. Each design offers a highly reliable system that can deliver 90% (Buck BCRs) or 80% (SEPIC BCRs) of the power delivered from the solar array network at full load. BCR Allocation The EPS has Buck and SEPIC BCRs as listed below. BCR Type 25-02451 25-02452 01-02453 Buck BCR N/A 1, 2 1, 2, 4, 5, 6, 7, 8, 9 SEPIC BCR 1,2,3,4 3 3 Buck BCR Power Stage The Buck BCRs allow the EPS to interface to strings of four to eight cells in series. This will deliver up to 90% output at full load. The design will operate with input voltages between 7.4V and 30V. If the maximum power point is below 9.4V, the MPPT will drift away from the maximum power point of the array at end of charge, sacrificing power system efficiency. SEPIC BCR Power Stage The SEPIC BCRs allow the EPS to interface to solar arrays of two triple junction cells in series. This will deliver up to 80% output at full load. The BCR will operate with an input of between 3.0V and 9.5V. 9.3 MPPT Each of the BCRs can have two solar arrays connected at any given time; only one array can be illuminated by sunlight, although the other may receive illumination by albedo reflection from earth. The dominant array is in sunlight and this will operate the MPPT for that BCR string. The MPPT monitors the power supplied from the solar array. This measurement is used to calculate the maximum power point of the array. The system tracks this point by periodically adjusting the BCRs to maintain the maximum power derived from the arrays. This technique ensures that the solar arrays can deliver much greater usable power, increasing the overall system performance. SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Page: 30 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Increasing Temperature Maximum Power Point Is/c Array Current I MPP Increasing Temperature V MPP V o/c Array Voltage Figure 9-2 Solar Array Maximum Power Point The monitoring of the MPP is done approximately every 2.5 seconds. During this tracking, the input of the array will step to o/c voltage, as shown in Figure 9-3. Figure 9-3 Input waveform with Maximum Power Point Tracking 9.4 5V USB Charge The EPS offers a method of trickle charging the battery by connecting a power supply directly to the 5V USB Charge pin on the header. The 5V USB Charge will operate with an input of between 3.0V and 6V. This charge connection utilises BCR3 to charge the battery and provides a parallel input to the 3W BCR. It should be noted that the 5V USB is designed for trickle charging the battery and as such will provide a maximum of 2.1W when operated at 6V input. 9.5 5V and 3.3V PCMs with Latching Current Limiter The 5V and 3.3V regulators both use buck switching topology regulators as their main converter stage. The regulator maintains the output voltage within +/- 1% of nominal. Efficiency curves are given in Figure 9-4 and Figure 9-5. The current limit of each regulator is nominally 4.5A. Each regulator operates at a frequency of 480 kHz. The Latching Current Limiter is described in Section 9.8. If an overcurrent event triggers the Latching Current Limiter a retry circuit will attempt to re-enable the bus as described in Section 10.1. SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 31 of 60 3V3 PCM Efficiency Over Load 100.00% Efficiency 95.00% 90.00% 85.00% 80.00% 75.00% 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 Load Current (A) Figure 9-4 Efficiency Curve for 3V3 PCM, Vbat=7.6v, Tbrd=23°C 5V PCM Efficiency Over Load 100.00% Efficiency 95.00% 90.00% 85.00% 80.00% 75.00% 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 Load Current (A) Figure 9-5 Efficiency Curve for 5V PCM, Vbat=7.6v, Tbrd=23°C SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 32 of 60 9.6 12V PCM with Latching Current Limiter The 12V regulator uses a boost switching topology regulator as the main converter stage. The regulator maintains the output voltage within +/- 1% of nominal. Efficiency is plotted in Figure 9-6. The current limit on the regulator is nominally 1.5A. The regulator operates at a frequency of 800 kHz. The Latching Current Limiter is described in Section 9.8. If an over-current event triggers the Latching Current Limiter, a retry circuit will attempt to re-enable the bus as described in Section 10.1. 12V PCM Efficiency Over Load 100.00% Efficiency 95.00% 90.00% 85.00% 80.00% 75.00% 0 0.2 0.4 0.6 0.8 1 1.2 1.4 Load Current (A) Figure 9-6 Efficiency Curve for 12V PCM, Vbat=7.6v, Tbrd=23°C 9.7 BatV PCM with Latching Current Limiter The unregulated battery voltage regulator provides safe access to the battery bus of the satellite. The voltage supplied will vary directly with the battery voltage (between 6.144V and 8.26V). The current limit is nominally 4.7A. The Latching Current Limiter is described in Section 9.8. If an over-current event triggers the Latching Current Limiter, a retry circuit will attempt to re-enable the bus as described in Section 10.1. 9.8 PDMs with Latching Current Limiter Ten independently commandable power distribution modules (PDM) are included on the EPS. Each PDM has inbuilt overcurrent protection in the form of a latching current limiter (LCL). By utilising an LCL each PDM is capable of driving loads with large inrush currents without compromising safety throughout the duration of the mission (this is of particular interest for applications such as transceivers). Once the LCL has activated, turning off the supply of power, the PDM will remain off until commanded to switch on again. The PDMs cover the range of regulated and unregulated voltages provided by the EPS. SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Page: 33 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK LCL Operation Description 4.5 (3) 4 Current (A) 3.5 (4) (1) 3 tlatch 2.5 ilatch 2 Current Demand (A) Current Supplied (A) 1.5 1 (2) 0.5 0 0 10 20 30 40 50 Time (ms) Figure 9-7 Latching Current Limiter Example Operation In the example system shown above the events are as follows: 1. The payload demands a 3A initial current, however the PDM limits the current to 2A. The time this demand is present is less than the latch time of the PDM (tlatch), so the PDM does not switch off. 2. The payload demand drops to 0.5A. This is below the current limit of the PDM (ilatch). 3. A fault condition occurs resulting in a demand of 4A. The PDM only allows 2A to pass, preventing high current damage to the PDM or the payload. 4. The fault remains for longer than tlatch so the PDM turns off preventing any current flow. SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 34 of 60 LCL Characteristics The following characteristics are specified at 25°C: • • • • PDM# ilatch: The latching current limit is set to allow the maximum safe current the EPS can deliver. This value has been selected based on the fact that, if the current limit is set high to allow a high inrush it will result in a high current limit during normal operation too. tlatch: The latching has been set to allow for the maximum safe length of time before shutting down the bus, allowing capacitive loads to be charged safely. clatch: This is the maximum capacitance that can be charged via the LCL before the PDM automatically disables. ton: Time delay from PDM being commanded to turn on via I2C node to actual PDM turn on. Pin Voltage (V) ilatch (A) tlatch (h) clatch (µF) ton (ms) 1 H2.08 12 1 - 1.1 2-3 240 0.140 2 H2.10 12 1 - 1.1 2-3 240 0.140 3 H2.11 BAT 4.2 - 4.3 8-9 800 0.140 4 H2.13 BAT 4.2 – 4.3 8-9 800 0.140 5 H2.13 5 1 - 1.1 8-9 1600 0.140 6 H2.15 5 1 - 1.1 8-9 1600 0.140 7 H2.16 5 1 - 1.1 8-9 1600 0.140 8 H2.18 3.3 1 - 1.1 13-14 4000 0.140 9 H2.19 3.3 1 - 1.1 13-14 4000 0.140 10 H2.20 3.3 1 - 1.1 13-14 4000 0.140 Table 9-1 PDM Switch Configuration SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 35 of 60 10. GENERAL PROTECTION The EPS (and wider power system) has a number of inbuilt protections and safety features designed to maintain safe operation of the EPS, battery and all subsystems supplied by the EPS buses. Figure 10-1 Protection Systems (When used with Manned Flight battery) 10.1 Over-Current Bus Protection (LCL) The EPS features bus protection systems to safeguard the battery, EPS and attached satellite subsystems. This is achieved using current monitors and a shutdown network within the PCMs. Over-current shutdowns are present on all buses for sub system protection. These are solid state switches that monitor the current and shut down at predetermined load levels. The bus protection will then monitor the fault periodically and reset when the fault clears. The fault detection and clear is illustrated in the waveform in Figure 10-2. OVER CURRENT EVENT SYSTEM SHUTDOWN TEST PERIOD EVENT CLEARS TEST PERIOD SYSTEM RESUME BUS VOLTAGE CURRENT NORMAL LEVEL NORMAL OPERATION NORMAL OPERATION Shutdown period Shutdown period Shutdown period Figure 10-2 Current protection system diagram The length of time of the test period will depend on the demand caused by the fault condition. Higher current demand results in a shorter test period. All PDMs and buses are protected against a short circuit fault. SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 Issue: D User Manual: 3rd Generation EPS Range - No Inhibits Date: 11/10/2017 Page: 36 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK 10.2 Battery Under-Voltage Protection In order to prevent the over-discharge of the battery, the EPS has in-built under-voltage shutdown. This is controlled by a comparator circuit with hysteresis. In the event of the battery discharging to ~6.144V (slightly above the level that results in significant battery degradation) the EPS will shut down the supply buses. This will also result in the I2C node shutting down. When a power source is applied to the EPS (e.g. an illuminated solar panel) the battery will begin charging immediately. The buses, however, will not reactivate until the battery voltage has risen to ~7V. This allows the battery to charge to a level capable of sustaining the power lines once a load is applied. It is recommended that the battery state of charge is monitored and loading adjusted appropriately (turning off of non-critical systems) when the battery capacity is approaching the lower limit. This will prevent the hard shutdown provided by the EPS. Once the under-voltage protection is activated there is a monitoring circuit used to monitor the voltage of the battery. This will draw approximately 2mA for the duration of shutdown. As the EPS is designed for low earth orbit, the maximum expected period in under-voltage is estimated to be approximately 40mins – after this time, the illuminated panels should bring the battery back above the 7V switch-on voltage. When ground testing this should be taken into consideration, and the battery should be recharged as soon as possible after reaching under-voltage, otherwise permanent damage may be sustained. SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 Issue: D User Manual: 3rd Generation EPS Range - No Inhibits Date: 11/10/2017 Page: 37 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK 11. TELEMETRY AND TELECOMMAND The telemetry node allows the satellite on board computer (OBC) to monitor the operation of the EPS, control switchable buses and reset the power supplies if this is required for payload or platform recovery operations. The telemetry node consists of a microcontroller which interfaces to the various telemetry sensing circuits on the EPS through an analogue multiplexer and ADC. The microcontroller is configured to connect through a buffer circuit to the I2C bus of the satellite as a slave node. In response to I2C telemetry requests the microcontroller will sample the desired channel and allowing it to be read back over the I2C bus. In response to a telecommand, the telemetry node will decode the incoming message and reset the desired power bus. 11.1 Communications All communications to the Telemetry and Telecommand (TTC) node are made using an I²C interface which is configured as a slave and only responds to direct commands from a master I²C node - no unsolicited telemetry is transmitted. The 7-bit I2C address of the TTC node is factory set at 0x2B and the I2C node will operate at a 100kHz bus clock. Command Protocol Two message structures are available to the master; a write command and a read command. The write command is used to initiate an event and the read command returns the result. All commands start with the 7-bit slave address and are followed by the data bytes. When reading responses, all data bytes should be read out together. Each command has a delay associated with it, this is required to allow the microcontroller time to process each request. During this delay, the correct response may not be returned, and commands sent during the period may be ignored. For a write command the first data byte will determine the command to be initiated. The second byte contains the parameters associated with that command. For commands which have no specific requirement for a parameter the second data byte should be set to 0x00. For a read command, the first data byte represents the most significant byte of the result and the second data byte represents the least significant byte. Before sending a command, the master is required to set a start condition on the I2C bus. Between each byte the receiving device is required to acknowledge receipt of the previous byte in accordance with the I2C protocol. This will often be accommodated within the driver hardware or software of the I2C master however the user should ensure that this is the case. The read and write command definitions are illustrated in Figure 11-1. SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 38 of 60 Write Command S 7 bit node address W A Command A Data Parameter A Read Command S 7 bit node address R A Data[1] A Data[0] N S Start Condition P Stop Condition Transmitted from Master (OBC) A N Acknowledge Not Acknowledged W R Write bit Read bit Transmitted from Slave (TTC node) P Figure 11-1 I2C Write and Read of 2 byte command packet If an error has been generated from a command, then the return value will be 0xFFFF. If this value is returned, it is recommended to either inspect the status bytes or to request the code representing the last error generated on the board as described in Section 11.3. SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 Issue: D User Manual: 3rd Generation EPS Range - No Inhibits Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 39 of 60 11.2 List of Available Commands 25-02451, 25-02452 01-02453 Command Data[1]2 Data[0] Bytes Returned W/R Delay Bytes Returned W/R Delay Board Status 0x01 NA 0x00 2 1 4 2 Get Last Error 0x03 NA 0x00 2 1 4 2 Get Version 0x04 NA 0x00 2 1 4 2 Get Checksum 0x05 NA 0x00 2 35 4 70 Get Revision 0x06 NA 0x00 2 1 4 2 Get Telemetry 0x10 2 5 2 15 Get Communications Watchdog Period 0x20 NA 0x00 2 1 2 1 Set Communications Watchdog Period 0x21 NA Period 0 - 0 - Reset Communications Watchdog 0x22 NA 0x00 0 - 0 - Get Number of Brown-out Resets 0x31 NA 0x00 2 1 4 2 Get Number of Auto Software Resets 0x32 NA 0x00 2 1 4 2 Get Number of Manual Resets 0x33 NA 0x00 2 1 4 2 Get Number of Comms Watchdog Resets 0x34 NA 0x00 2 1 2 1 Switch On All PDMs 0x40 NA 0x00 0 - 0 - Switch Off All PDMs 0x41 NA 0x00 0 - 0 - Get Actual State of All PDMs 0x42 NA 0x00 4 20 4 20 Get Expected State of All PDMs 0x43 NA 0x00 4 1 4 1 Get Initial State of All PDMs 0x44 NA 0x00 4 20 4 20 Set All PDMs to Initial State 0x45 NA 0x00 4 20 4 20 Switch PDM-N “On" 0x50 NA N 0 - 0 - Switch PDM-N “Off” 0x51 NA N 0 - 0 - Set PDM-N’s Initial State to “On” 0x52 NA N 0 200 0 200 Set PDM-N’s Initial State to “Off” 0x53 NA N 0 200 0 200 Get PDM-N’s Actual Status 0x54 NA N 2 2 2 2 Set PDM-N’s Timer Limit 0x60 N Limit 0 200 0 150 Get PDM-N’s Timer Limit 0x61 NA N 0 5 0 5 Get PDM-N’s Current Timer Value 0x62 NA N 0 1 0 1 PCM Reset 0x70 NA Table 11-14 0 1 0 1 Manual Reset 0x80 NA 0x00 0 - 0 - Name Table 11-8 2 Where a command has Data[1] listed as NA, the command only requires a single data byte to be transmitted. This will be given by Data[0]. SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 40 of 60 11.3 Housekeeping and Status Commands Board Status (0x01) Command Data[0] Bytes Returned Delay, ms 25-02451, 25-02452 0x01 0x00 2 1 01-02453 0x01 0x00 4 2 The status bytes are designed to supply operational data about the I2C Node. To retrieve the data that represent the status, the command 0x01 should be sent followed by 0x00. The meaning of each bit of the returned status bytes is shown below. Please note that Data[1] is the first byte returned from the EPS and Data[0] is the last, this is shown in detail by Figure 11-1. The first two bytes returned represent the status of the motherboard and, in the case of 01-02453, a further two bytes are returned to reflect the status for the daughterboard. Data[n] 0 Bit Description 0 Set HIGH if last command not recognised 1 Set HIGH if a watchdog error occurred, resetting the device 2 Set HIGH if the data sent along with the last command was incorrect 3 Set HIGH if the channel passed with the last command was incorrect 4 Set HIGH if there has been an error reading the EEPROM 5 Set HIGH if a Power On Reset error occurred 6 Set HIGH if a Brown Out Reset occurred 7 Unused 0 1 … Unused 7 Table 11-2 Status bits for EPS SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 41 of 60 Get Last Error (0x03) Command Data[0] Bytes Returned Delay, ms 25-02451, 25-02452 0x03 0x00 2 1 01-02453 0x03 0x00 4 2 If an error has been generated after attempting to execute a user’s command the value 0xFFFF is returned. To retrieve the details of the last error, send the command 0x03 followed by the data byte 0x00. This will return the code of the last error generated. Details of each error code are given by Table 11-3. The first two bytes returned represent the Motherboard’s error code and, in the case of 0102453, the second two bytes represent the Daughterboard’s. Code Description 0x10 CRC code does not match data 0x01 Unknown command received 0x02 Supplied data incorrect when processing command 0x03 Selected channel does not exist 0x04 Selected channel is currently inactive 0x13 A reset had to occur 0x14 There was an error with the ADC acquisition 0x20 Reading from EEPROM generated an error 0x30 Generic warning about an error on the internal SPI bus (only if daughterboard is connected) Table 11-3 List of Clyde Space Error Codes Get Version (0x04) Command Data[0] Bytes Returned Delay, ms 25-02451, 25-02452 0x04 0x00 2 1 01-02453 0x04 0x00 4 2 The version number of the firmware will be returned on this command. Data[1] Bit 15 14 13 12 Value 11 Data[0] 10 9 8 7 6 5 4 3 2 1 0 Board Firmware Number Table 11-4 Returned Firmware Version Number SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 42 of 60 Get Checksum (0x05) Command Data[0] Bytes Returned Delay, ms 25-02451, 25-02452 0x05 0x00 2 35 01-02453 0x05 0x00 4 70 This command instructs the node to self-inspect its ROM contents in order to generate a checksum. The value retrieved can be used to determine whether the contents of the ROM have changed during the operation of the device. The first two bytes returned represent the motherboard checksum and, in the case of 01-02453, a further two bytes are returned to for the daughterboard checksum. Data[1] Bit 7 6 5 4 3 Data[0] 2 1 Value 0 7 6 5 4 3 2 1 0 Board Checksum Get Firmware Revision (0x06) Command Data[0] Bytes Returned Delay, ms 25-02451, 25-02452 0x06 0x00 2 1 01-02453 0x06 0x00 4 2 The revision version number of the firmware will be returned on this command. Data[1] Bit 15 14 13 12 Value 11 Data[0] 10 9 8 7 6 5 4 3 2 1 0 Board Firmware Revision Number Table 11-5 Returned Firmware Revision Number Manual Reset (0x80) Command Data[0] Bytes Returned Delay, ms 0x80 0x00 0 - If required, the user can reset the TTC node using this command. When issued, the board will reset within 1 second. This command will result in the board being brought up in its defined initial condition. Resetting the board in this fashion will increment the Manual Reset Counter. More details about this counter are found in section 11.5. SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 43 of 60 11.4 Telemetry The node telemetries allow the satellite’s on board computer (OBC) to monitor the operation of the EPS. Each available telemetry is represented by a two-byte code. These codes consist of: • What type of telemetry is requested, i.e. PDM or PCM, analogue inputs, or some other form of sensor. The channel being requested. The reading to take: voltage, current, temperature etc. • • A break-down of the telemetry structure and commands is given below. If a telemetry is requested which is not available, a Channel Error will be generated. Get Telemetry (0x10) Command Data[1] Data[0] Bytes Returned Delay, ms Table 11-11 Telemetries 0x10 0xE? 0x?? 2 15 All other telemetries 0x10 0xE? 0x?? 2 5 As described above, requesting telemetry involves sending the command 0x10 plus a 2 byte telemetry code to the node. Once transmitted, the node will configure itself to read the requested value. The general format for telemetry codes is shown in Table 11-6, and an exhaustive list of commands in Table 11-8 through Table 11-11 – refer to the table annotations for applicability to particular products. The data returned will be in the format shown in Table 11-7. Data[1] Nibble 3 Family EPS EPS Data[0] Nibble 2 Code E E TLM Type BCR Main Power Nibble 1 Code 1 2 Channel Nibble 0 Code Channel Number N Attribute Code Voltage 0 Current A 4 Current B 5 Temperature A 8 Temperature B 9 N Core Bus Miscellaneous 0 to 7 8 to F Voltage 0 Current A Temperature 8 Voltage 0 Current 4 EPS E Temperature 3 Motherboard 0 to 7 EPS E PDM 4 to 7 Switch Number N N mod 16 Table 11-6 Breakdown of Clyde Space telemetry code structure. SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 44 of 60 Data[1] Data[0] Bit 15 14 13 12 11 10 Value 0 0 0 0 0 0 9 8 7 6 5 4 3 2 1 0 ADC Result Table 11-7 ADC result return format The result should then be converted to physical units via the conversion equations in Table 11-8. The equations provided in Table 11-8 are the theoretical equations for the system. If more accurate telemetry results are required, tailored equations are available from the test report for the individual product which will be supplied with the hardware. The advantage of using tailored equations is that they compensate for component tolerances and parasitic losses in an individual build of an EPS, however the tailored equations will vary slightly for every EPS manufactured and therefore may be different between flight and engineering model hardware. Name IIDIODE_OUT VIDIODE_OUT I3V3_DRW I5V_DRW TLE Code 0xE284 0xE280 0xE205 0xE215 Description BCR output current BCR output voltage 3V3 Current Draw of EPS 5V Current Draw of EPS Uncalibrated Conversion Equation 14.662757 x ADC Count 0.008993157 x ADC Count 0.001327547 x ADC Count 0.001327547 x ADC Count Units mA V A A IPCM12V VPCM12V IPCMBATV VPCMBATV IPCM5V VPCM5V IPCM3V3 VPCM3V3 0xE234 0xE230 0xE224 0xE220 0xE214 0xE210 0xE204 0xE200 Output Current of 12V Bus Output Voltage of 12V Bus Output Current of Battery Bus Output Voltage of Battery Bus Output Current of 5V Bus Output Voltage of 5V Bus Output Current of 3.3V Bus Output Voltage of 3.3V Bus 0.00207 x ADC Count 0.01349 x ADC Count 0.005237 x ADC Count 0.008978 x ADC Count 0.005237 x ADC Count 0.005865 x ADC Count 0.005237 x ADC Count 0.004311 x ADC Count A V A V A V A V VSW1 ISW1 VSW2 ISW2 VSW3 ISW3 VSW4 ISW4 VSW5 ISW5 VSW6 ISW6 VSW7 ISW7 VSW8 ISW8 VSW9 ISW9 VSW10 ISW10 0xE410 0xE414 0xE420 0xE424 0xE430 0xE434 0xE440 0xE444 0xE450 0xE454 0xE460 0xE464 0xE470 0xE474 0xE480 0xE484 0xE490 0xE494 0xE4A0 0xE4A4 Output Voltage Switch 1 Output Current Switch 1 Output Voltage Switch 2 Output Current Switch 2 Output Voltage Switch 3 Output Current Switch 3 Output Voltage Switch 4 Output Current Switch 4 Output Voltage Switch 5 Output Current Switch 5 Output Voltage Switch 6 Output Current Switch 6 Output Voltage Switch 7 Output Current Switch 7 Output Voltage Switch 8 Output Current Switch 8 Output Voltage Switch 9 Output Current Switch 9 Output Voltage Switch 10 Output Current Switch 10 0.01349 x ADC Count 0.001328 x ADC Count 0.01349 x ADC Count 0.001328 x ADC Count 0.008993 x ADC Count 0.006239 x ADC Count 0.008993 x ADC Count 0.006239 x ADC Count 0.005865 x ADC Count 0.001328 x ADC Count 0.005865 x ADC Count 0.001328 x ADC Count 0.005865 x ADC Count 0.001328 x ADC Count 0.004311 x ADC Count 0.001328 x ADC Count 0.004311 x ADC Count 0.001328 x ADC Count 0.004311 x ADC Count 0.001328 x ADC Count V A V A V A V A V A V A V A V A V A V A TBRD 0xE308 Motherboard Temperature (0.372434 x ADC Count) -273.15 °C Table 11-8 List of Telemetry Codes Common to All Products SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Page: 45 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Name VBCR1 IBCR1A IBCR1B TBCR1A TBCR1B SDBCR1A SDBCR1B TLE Code 0xE110 0xE114 0xE115 0xE118 0xE119 0xE11C 0xE11D Description Voltage feeding BCR1 Current BCR1, Connector SA1A Current BCR1, Connector SA1B Array Temp, Connector SA1A Array Temp, Connector SA1B Sun Detector, Connector SA1A Sun Detector, Connector SA1B Uncalibrated Conversion Equation 0.009971 x ADC Count 0.977517107 x ADC Count 0.977517107x ADC Count 0.4963 x ADC Count 0.4963 x ADC Count 1.59725 x ADC Count 1.59725 x ADC Count Units V A A °C °C W/m2 W/m2 VBCR2 IBCR2A IBCR2B TBCR2A TBCR2B SDBCR2A SDBCR2B 0xE120 0xE124 0xE125 0xE128 0xE129 0xE12C 0xE12D Voltage feeding BCR2 Current BCR1, Connector SA2A Current BCR1, Connector SA2B Array Temp, Connector SA2A Array Temp, Connector SA2B Sun Detector, Connector SA2A Sun Detector, Connector SA2B 0.009971 x ADC Count 0.977517107x ADC Count 0.977517107x ADC Count 0.4963 x ADC Count 0.4963 x ADC Count 1.59725 x ADC Count 0.571428571 x ADC Count V A A °C °C W/m2 W/m2 VBCR33 IBCR3A4 IBCR3B TBCR3A TBCR3B SDBCR3A SDBCR3B 0xE130 0xE134 0xE135 0xE138 0xE139 0xE13C 0xE13D Voltage feeding BCR3 Current BCR1, Connector SA3A Current BCR1, Connector SA3B Array Temp, Connector SA3A Array Temp, Connector SA3B Sun Detector, Connector SA3A Sun Detector, Connector SA3B 0.009971 x ADC Count 0.977517107x ADC Count 0.977517107x ADC Count 0.4963 x ADC Count 0.4963 x ADC Count 1.59725 x ADC Count 1.59725 x ADC Count V A A °C °C W/m2 W/m2 VBCR4 IBCR4A IBCR4B TBCR4A TBCR4B SDBCR4A SDBCR4B 0xE140 0xE144 0xE145 0xE148 0xE149 0xE14C 0xE14D Voltage feeding BCR4 Current BCR1, Connector SA4A Current BCR1, Connector SA4B Array Temp, Connector SA4A Array Temp, Connector SA4B Sun Detector, Connector SA4A Sun Detector, Connector SA4B 0.009971 x ADC Count 0.977517107x ADC Count 0.977517107x ADC Count 0.4963 x ADC Count 0.4963 x ADC Count 1.59725 x ADC Count 1.59725 x ADC Count V A A °C °C W/m2 W/m2 Table 11-9 List of Telemetry Codes Unique to 25-02451 3 4 Telemetry VBCR3 can be used to monitor the input voltage from 5V USB CHG Telemetry IBCR3A can be used to monitor the current draw from 5V USB CHG SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Page: 46 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Name VBCR1 IBCR1A IBCR1B TBCR1A TBCR1B SDBCR1A SDBCR1B TLE Code 0xE110 0xE114 0xE115 0xE118 0xE119 0xE11C 0xE11D Description Voltage feeding BCR1 Current BCR1, Connector SA1A Current BCR1, Connector SA1B Array Temp, Connector SA1A Array Temp, Connector SA1B Sun Detector, Connector SA1A Sun Detector, Connector SA1B Uncalibrated Conversion Equation 0.0322581 x ADC Count 0.0009775 x ADC Count 0.0009775 x ADC Count (0.4963 x ADC Count) - 273.15 (0.4963 x ADC Count) - 273.15 1.59725 x ADC Count 1.59725 x ADC Count Units V A A °C °C W/m2 W/m2 VBCR2 IBCR2A IBCR2B TBCR2A TBCR2B SDBCR2A SDBCR2B 0xE120 0xE124 0xE125 0xE128 0xE129 0xE12C 0xE12D Voltage feeding BCR2 Current BCR2, Connector SA2A Current BCR2, Connector SA2B Array Temp, Connector SA2A Array Temp, Connector SA2B Sun Detector, Connector SA2A Sun Detector, Connector SA2B 0.0322581 x ADC Count 0.0009775 x ADC Count 0.0009775 x ADC Count (0.4963 x ADC Count) - 273.15 (0.4963 x ADC Count) - 273.15 1.59725 x ADC Count 1.59725 x ADC Count V A A °C °C W/m2 W/m2 VBCR35 IBCR3A6 IBCR3 TBCR3 TBCR3B SDBCR3A SDBCR3B 0xE130 0xE134 0xE135 0xE138 0xE139 0xE13C 0xE13D Voltage feeding BCR3 Current BCR3, Connector SA3A Current BCR3, Connector SA3B Array Temp, Connector SA3A Array Temp, Connector SA3B Sun Detector, Connector SA3A Sun Detector, Connector SA3B 0.0099706 x ADC Count 0.0009775 x ADC Count 0.0009775 x ADC Count (0.4963 x ADC Count) - 273.15 (0.4963 x ADC Count) - 273.15 1.59725 x ADC Count 1.59725 x ADC Count V A A °C °C W/m2 W/m2 Table 11-10 List of Telemetry Codes Common to 25-02452 and 01-02453 5 6 Telemetry VBCR3 can be used to monitor the input voltage from 5V USB CHG Telemetry IBCR3A can be used to monitor the current draw from 5V USB CHG SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Page: 47 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Name VBCR4 IBCR4A IBCR4B TBCR4A TBCR4B SDBCR4A SDBCR4B TLE Code 0xE140 0xE144 0xE145 0xE148 0xE149 0xE14C 0xE14D Description Voltage feeding BCR4 Current BCR4, Connector SA4A Current BCR4, Connector SA4B Array Temp, Connector SA4A Array Temp, Connector SA4B Sun Detector, Connector SA4A Sun Detector, Connector SA4B Uncalibrated Conversion Equation 0.0322581 x ADC Count 0.0009775 x ADC Count 0.0009775 x ADC Count (0.4963 x ADC Count) -273.15 (0.4963 x ADC Count) -273.15 1.59725 x ADC Count 1.59725 x ADC Count Units V mA mA °C °C W/m2 W/m2 VBCR5 IBCR5A IBCR5B TBCR5A TBCR5B SDBCR5A SDBCR5B 0xE150 0xE154 0xE155 0xE158 0xE159 0xE15C 0xE15D Voltage feeding BCR5 Current BCR5, Connector SA5A Current BCR5, Connector SA5B Array Temp, Connector SA5A Array Temp, Connector SA5B Sun Detector, Connector SA5A Sun Detector, Connector SA5B 0.0322581 x ADC Count 0.0009775 x ADC Count 0.0009775 x ADC Count (0.4963 x ADC Count) -273.15 (0.4963 x ADC Count) -273.15 1.59725 x ADC Count 1.59725 x ADC Count V mA mA °C °C W/m2 W/m2 VBCR6 IBCR6A IBCR6B TBCR6A TBCR6B SDBCR6A SDBCR6B 0xE160 0xE164 0xE165 0xE168 0xE169 0xE16C 0xE16D Voltage feeding BCR6 Current BCR6, Connector SA6A Current BCR6, Connector SA6B Array Temp, Connector SA6A Array Temp, Connector SA6B Sun Detector, Connector SA6A Sun Detector, Connector SA6B 0.0322581 x ADC Count 0.0009775 x ADC Count 0.0009775 x ADC Count (0.4963 x ADC Count) -273.15 (0.4963 x ADC Count) -273.15 1.59725 x ADC Count 1.59725 x ADC Count V mA mA °C °C W/m2 W/m2 VBCR7 IBCR7A IBCR7B TBCR7A TBCR7B SDBCR7A SDBCR7B 0xE170 0xE174 0xE175 0xE178 0xE179 0xE17C 0xE17D Voltage feeding BCR7 Current BCR7, Connector SA7A Current BCR7, Connector SA7B Array Temp, Connector SA7A Array Temp, Connector SA7B Sun Detector, Connector SA7A Sun Detector, Connector SA7B 0.0322581 x ADC Count 0.0009775 x ADC Count 0.0009775 x ADC Count (0.4963 x ADC Count) -273.15 (0.4963 x ADC Count) -273.15 1.59725 x ADC Count 1.59725 x ADC Count V mA mA °C °C W/m2 W/m2 VBCR8 IBCR8A IBCR8B TBCR8A TBCR8B SDBCR8A SDBCR8B 0xE180 0xE184 0xE185 0xE188 0xE189 0xE18C 0xE18D Voltage feeding BCR8 Current BCR8, Connector SA8A Current BCR8, Connector SA8B Array Temp, Connector SA8A Array Temp, Connector SA8B Sun Detector, Connector SA8A Sun Detector, Connector SA8B 0.0322581 x ADC Count 0.0009775 x ADC Count 0.0009775 x ADC Count (0.4963 x ADC Count) -273.15 (0.4963 x ADC Count) -273.15 1.59725 x ADC Count 1.59725 x ADC Count V mA mA °C °C W/m2 W/m2 VBCR9 IBCR9A IBCR9B TBCR9A TBCR9B SDBCR9A SDBCR9B 0xE190 0xE194 0xE195 0xE198 0xE199 0xE19C 0xE19D Voltage feeding BCR9 Current BCR9, Connector SA9A Current BCR9, Connector SA9B Array Temp, Connector SA9A Array Temp, Connector SA9B Sun Detector, Connector SA9A Sun Detector, Connector SA9B 0.0322581 x ADC Count 0.0009775 x ADC Count 0.0009775 x ADC Count (0.4963 x ADC Count) -273.15 (0.4963 x ADC Count) -273.15 1.59725 x ADC Count 1.59725 x ADC Count V mA mA °C °C W/m2 W/m2 TLM_TBRD_DB 0xE388 Daughterboard Temperature (0.372434 x ADC Count) -273.15 °C Table 11-11 List of Telemetry Codes Unique to 01-02453 SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 Issue: D User Manual: 3rd Generation EPS Range - No Inhibits Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 48 of 60 11.5 Watchdogs and Reset Counters Two on-board watchdog timers are used to restart the device if it becomes non-operational due to an error in the microcontroller. The Communications Watchdog is used to reset the device if a designated period passes during which the device receives no data on the I2C bus. The second watchdog is the on-board Software Watchdog which is used to reset the device if the microcontroller has malfunctioned. If the node determines that an error has occurred, the device is rebooted into its predefined initial state. Both watchdogs have associated counters which can be queried to determine the number of times the device has reset itself through either a lack of communications or a software error. A third counter is also available which maintains a record of how many times the device is reset from a Brown-Out condition. Get Communications Watchdog Period (0x20) Command Data[0] Bytes Returned Delay, ms 0x20 0x00 2 1 This command provides the user with the current communications watchdog timeout that has been set. The returned value is indicated in minutes. Set Communications Watchdog Period (0x21) Command Data[0] Bytes Returned Delay, ms 0x21 Period 0 - The Communications Watchdog by default has a value of 4 minutes set as its timeout period. If 4 minutes pass without a command being received, then the device will reboot into its pre-defined initial state. This value of 4 minutes can be changed using the Set Communications Watchdog Period command, 0x21. The data byte specifies the number of minutes the communications watchdog will wait before timing out. A minimum value of 1 minute or a maximum of 90 minutes can be set. The device will always reboot with a timeout value of 4 minutes set. If an invalid value is specified, the device will generate a Data Error. Reset Communications Watchdog (0x22) Command Data[0] Bytes Returned Delay, ms 0x22 0x00 0 1 Any valid command will reset the communications watchdog timer. If the user does not require any telemetry from the board, this command can be sent to reset the communications watchdog. SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 Issue: D User Manual: 3rd Generation EPS Range - No Inhibits Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 49 of 60 Get Number of Brown-out Resets (0x31) Command Data[0] Bytes Returned Delay, ms 25-02451, 25-02452 0x31 0x00 2 1 01-02453 0x31 0x00 4 2 This counter is designed to keep track of the number of brown-out resets that have occurred. This counter will roll over at 255 to 0. The first two bytes outputted represent the Motherboard’s value, the second two (01-02453 only) represent the Daughterboard’s. Get Number of Automatic Software Resets (0x32) Command Data[0] Bytes Returned Delay, ms 25-02451, 25-02452 0x32 0x00 2 1 01-02453 0x32 0x00 4 2 If the on-board microcontroller has experienced a malfunction, such as being stuck in a loop, it will reset itself into a pre-defined initial state. Using this command, 0x32, it is possible to retrieve the number of times this reset has occurred. The first two bytes outputted represent the Motherboard’s value, the second two (01-02453 only) represent the Daughterboard’s. This counter will roll over at 255 to 0. Get Number of Manual Resets (0x33) Command Data[0] Bytes Returned Delay, ms 25-02451, 25-02452 0x33 0x00 2 1 01-02453 0x33 0x00 4 2 A count is kept of the number of times the device has been manually reset using the Reset command. Sending the command 0x33 with data byte 0x00 will return the number of times the device has been reset in this fashion. The first two bytes outputted represent the Motherboard’s value, the second two (01-02453 only) represent the Daughterboard’s. This counter will roll over at 255 to 0. Get Number of Communications Watchdog Resets Command Data[0] Bytes Returned Delay, ms 0x34 0x00 2 1 As described previously, the device will reset itself if it does not receive any data via I2C for a predefined length of time. The communications node keeps a count of the number of times such an event has taken place. Sending the command 0x34 along with the data byte 0x00 will return the number of communication watchdog resets. This counter will roll over at 255 to 0. SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 50 of 60 11.6 PDM Control On-board power distribution modules can either be controlled via commands which address them individually or all at once. Associated with each module is its expected status, its actual status and the state it will be initialised with when the EPS is powered on or reset. Switch On All PDMs (0x40) Command Data[0] Bytes Returned Delay, ms 0x40 0x00 0 - Command Data[0] Bytes Returned Delay, ms 0x41 0x00 0 - Command Data[0] Bytes Returned Delay, ms 0x42 0x00 4 20 When this command is issued, all PDMs switch on. Switch Off All PDMs (0x41) When this command is issued, all PDMs switch off. Get Actual State of All PDMs (0x42) The PDMs have over-current protection built in. As a result, a PDM that is expected to be on may have tripped. This command returns the actual state of all the PDMs. The bits within the bytes returned represent the state of each PDM, with 0 representing off and 1 representing on. The order of bits is shown in Table 11-12. Bit Data[3] Data[2] Data[1] Data[0] 7 PDM 7 6 PDM 6 5 PDM 5 4 PDM 4 3 PDM 3 2 PDM 10 PDM 2 1 PDM 9 PDM 1 0 PDM 8 - Table 11-12 PDM Byte Codes. Get Expected State of All PDMs (0x43) Command Data[0] Bytes Returned Delay, ms 0x43 0x00 4 1 This command returns the expected state of all the PDMs – that is, whether they have been commanded on or off, regardless of whether overcurrent protection has tripped. The format of the returned data is given by Table 11-12, with 0 representing OFF and 1 representing ON. SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 Issue: D User Manual: 3rd Generation EPS Range - No Inhibits Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 51 of 60 Get Initial State of All PDMs (0x44) Command Data[0] Bytes Returned Delay, ms 0x44 0x00 4 20 The initial state of the PDMs is returned using this command. The initial state for all the PDMs is returned in response to this command. The bit indication is the same as that in Table 11-12, with a 1 indicating the PDM is selected to be ON at power up or reset Set All PDMs to Initial State Command Data[0] Bytes Returned Delay, ms 0x45 0x00 0 20 This command sets the initial state of the PDMs after power on or reset. This includes resetting all timers associated with each PDM (See Section 11.7 for more information about PDM Timers). Switch PDM-N “On" (0x50) Command Data[0] Bytes Returned Delay, ms 0x50 Channel # 0 - This command turns on an individual PDM defined in the data byte, PDM 1 is 0x01, PDM2 is 0x02 etc. If an invalid channel is specified, 0xFFFF is returned and the device will generate an Invalid Channel error. Switch PDM-N “Off” (0x51) Command Data[0] Bytes Returned Delay, ms 0x51 Channel # 0 - This command turns off an individual PDM defined in the data byte, PDM 1 is 0x01, PDM2 is 0x02 etc. If an invalid channel is specified, 0xFFFF will be returned and the device will generate an Invalid Channel error. Set PDM-N’s Initial State to “On” (0x52) Command Data[0] Bytes Returned Delay, ms 0x52 Channel # 0 200 Using the command 0x52 allows a PDM’s initial status to be set to ON. After a reset or reboot, this PDM channel will be enabled. The channel is specified in the data byte, PDM 1 is 0x01, PDM2 is 0x02 etc. If an invalid channel is specified, 0xFFFF will be returned and the device will generate an Invalid Channel error. SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 Issue: D User Manual: 3rd Generation EPS Range - No Inhibits Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 52 of 60 Set PDM-N’s Initial State to “Off” (0x53) Command Data[0] Bytes Returned Delay, ms 0x53 Channel # 0 200 Using command 0x53 allows a PDM’s initial status to be set to OFF. After a reset or reboot, this PDM channel will be disabled. The channel is specified in the data byte, PDM 1 is 0x01, PDM2 is 0x02 etc. If an invalid channel is specified, 0xFFFF will be returned and the device will generate an Invalid Channel error. Get PDM-N’s Actual Status (0x54) Command Data[0] Bytes Returned Delay, ms 0x54 Channel # 2 2 The PDMs have overcurrent protection; as a result, a PDM that is expected to be on may have tripped. This command returns the actual state of the requested PDM specified in the data byte, PDM 1 is 0x01, PDM2 is 0x02 etc. A returned value of 1 indicates the PDM is ON and a returned value of 0 indicates the PDM is OFF. SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 Issue: D User Manual: 3rd Generation EPS Range - No Inhibits Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 53 of 60 11.7 PDM Timers Each Power Distribution Module has a user configurable timer associated which allows the maximum time the PDM can be ON for to be set. Unless there is user intervention, the PDM will switch OFF after this period. This feature can be useful for high power circuitry which could drain a craft’s power supply if not monitored correctly. A minimum duration of 30 seconds can be set and a maximum of 127 minutes. Through the PDM Timer Control each PDM can be in one of three states: • • • Permanently Disabled: Any attempt to enable the PDM will fail. Enabled without timer restrictions: Once switched on, the PDM will remain enabled indefinitely. Enabled with timer restrictions: Once switched on, the PDM will only remain on for a predefined period of time. Out of the box, each PDM is set up without timer restrictions. Once configured the timer settings are stored in EEPROM and remain in effect even after a reboot. Theory of Operation Each PDM timer has two values associated with its control: PDM Timer Limit: This is the maximum length of time the PDM will remain on for. When set to 0xFF, the timer will remain on indefinitely when enabled. If set to 0x00 the timer will always remain off, regardless of any attempt to enable it. If a command is sent to switch on a disabled channel, the error INACTIVE CHANNEL (0x04) will be generated. The timer limit is set in multiples of 30 Seconds; therefore, supplying a value of 0x0A will set the PDM’s enabled duration to 5 minutes. Associated Commands: Set PDM Timer Limit (0x60) and Get PDM Timer Limit (0x61) PDM Timer Current Value: The Current Value of the timer is the length of time the timer has been enabled for. Again, its values are in multiples of 30 seconds. Returned values are always rounded down. Therefore, if the PDM has been on for 7 minutes and 20 seconds the expected Timer Current Value of 0x0E would be returned. Set PDM N ON 0x00 Check PDM N's 'Timer Limit' 0xFF PDM N On Other Set PDM N's Current Timer Value to 0 Independant, non-locking thread PDM N On Associated Commands: Get PDM Current Value (0x62) If a PDM is enabled and its timer is active, sending a Set PDM On command to the PDM will set its current value to zero, effectively resetting the timer count. This means that from the moment a Set PDM On command is received the PDM will remain active for its full Timer Limit duration. Timer Tick Is PDM N's current timer value less than PDM N's Timer Limit? Yes Increment PDM N's current timer value No PDM N OFF The diagram in Figure 11-12 shows the operation of the Figure 11-13 Operation of the PDM Timer State Machine timer as a Set PDM On command is received. SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 Issue: D User Manual: 3rd Generation EPS Range - No Inhibits Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 54 of 60 Set PDM-N’s Timer Limit (0x60) Command Data[1] Data[0] Bytes Returned Delay, ms 0x60 Channel # Period 0 150 Set the length of time a channel can remain enabled for. The value supplied gives the duration in increments of 30 seconds, e.g. duration=0x0A would enable the PDM for 5 minutes. Supplying a value of period=0xFF sets the PDM to remain enabled indefinitely. A value of period=0x00 will permanently disable the PDM until such time that the timer is set to a value greater than 0x00. If an invalid channel is specified, 0xFFFF will be returned and the device will generate an Invalid Channel error. If an invalid period is specified, 0xFFFF will be returned and the device will generate an Invalid Data error. Get PDM-N’s Timer Limit (0x61) Command Data[0] Bytes Returned Delay, ms 0x61 Channel # 2 5 Returns the maximum timer value currently set for the PDM. Durations are returned in increments of 30 seconds, e.g. duration=0x0A would mean the PDM was enabled for a total of 5 minutes. Get PDM-N’s Current Timer Value (0x62) Command Data[0] Bytes Returned Delay, ms 0x62 Channel # 2 1 Returns the time passed since the PDMs timer was enabled. Durations are returned in increments of 30 seconds, e.g. duration=0x0A would mean the PDM has been enabled for a total of 5 minutes SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 Issue: D User Manual: 3rd Generation EPS Range - No Inhibits Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 55 of 60 11.8 PCM Control PCM Reset (0x70) Command Data[0] Bytes Returned Delay, ms 0x70 PCM Channels 0 1 The individual power buses on the EPS can be reset using this command. Table 11-14 provides the breakdown of the data bits to reset a power bus. Power Bus Bit String Battery V 0x01 5V 0x02 3.3 V 0x04 12 V 0x08 Table 11-14 Power bus Breakdown A combination of the bit strings can also be used. For example, to reset the 5V and the Battery V bus, send the data 0x03. When this command is used, the chosen power bus, or buses, will be held in reset for a period of approximately 500ms. This has the effect of turning off the power bus for this period of time. It should be noted that when the 3.3V power bus is reset, communication to the TTC node will be lost for the period of time the bus is held in reset. The TTC node will power up in its initial configuration. 12. TEST All EPS units are fully tested prior to shipping, and test reports are supplied. In order to verify the operation of the EPS please use the following outlined instructions. 12.1 Required Equipment • • • • • • • Solar Arrays (or simulated solar array supply) EPS Battery (or simulated battery) Oscilloscope Multimeter Electronic Load Method to communicate with TTC node, eg. USB-I2C adaptor SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Page: 56 of 60 Figure 12-1 Full System Required for Test Solar Arrays During test phases it is not always possible to use solar arrays for testing. Other options for testing include solar array simulators or (for approximation testing) a PSU and an inline resistor. If using a solar array simulator, it is important to ensure that the setup does not exceed the operating limits of the EPS. Table 12-1 shows the characteristics of the different compatible panel setups for the arrays. Series Cells Voc (V) Vmpp (V) Isc (mA) Impp (mA) Compatible BCRs 2 5.32 4.70 453.871 433.906 SEPIC BCRs 3 7.98 7.05 453.871 433.906 SEPIC BCRs 4 10.64 9.40 453.871 433.906 Buck BCRs 5 13.30 11.75 453.871 433.906 Buck BCRs 6 15.96 14.10 453.871 433.906 Buck BCRs 7 18.62 16.45 453.871 433.906 Buck BCRs 8 21.28 18.80 453.871 433.906 Buck BCRs Table 12-1 Examples of Solar Array Configurations – Spectrolab UTJ cells @ BOL, 28ºC If a solar array simulator is not available, it is possible to approximate solar array operation with a power supply and an inline power resistor. Figure 12-2 Simulated Solar Array Setup The value of the resistor will set the current supplied and can be calculated as follows: SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 Issue: D User Manual: 3rd Generation EPS Range - No Inhibits Date: 11/10/2017 𝑅𝑖𝑛 = Page: 57 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK 0.17 × 𝑉𝑜𝑐 𝐼𝑖𝑛 Iin = the current required (normally the maximum power point current) Rin = the resistance of the inline resistor selected Voc = the expected open circuit voltage of the solar array. Iin is normally set, using Rin, to match the maximum power point current (Impp) of the expected array, but can be adjusted to simulate lower illumination conditions. The PSU should be set using Voc as the voltage setting and 2x Iin as the current limit (Ipsua) Battery During test phases it is not always possible or advisable to use a battery. For example, to test End of Charge or undervoltage shutdown operation you may want to alter the battery voltage manually rather than wait for a battery to charge/discharge. Also testing with a power supply avoids unnecessary stress on the battery from testing at high currents. When testing without a battery, the system requires a simulated battery to be attached. This can be achieved by using a PSU (to set the battery and supply current when required/discharging) and an electronic load (to simulate the battery taking current/charging) connected in parallel. Figure 12-3 Simulated Battery Setup The PSU should be set using the voltage as the required battery voltage (Vpsub) and a current limit of 2C (Ipsub) (the highest recommended discharge rate of the battery). The electronic load current (Ieloadb) setting should be set to approximately 1C of the battery to be used. You must also ensure the eLoad setting is higher than the supplied BCR current, otherwise the BCR will be pushed into EoC. 12.2 Standalone Test Setup The following instructions detail how to perform a test of the EPS using a simulated battery. Before any testing commences all equipment described above should be configured with limits set up appropriately. All PSUs should be switched off. 1. Connect the simulated battery between GND (H2.32) and PCM_IN (H2.36) 2. Place another wire between BCR_OUT (H2.42) and PCM_IN (H2.36) (make sure that the wire has enough current carrying capability). 3. Connect the solar array (or simulated solar array). SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 Issue: D 4. 5. 6. 7. User Manual: 3rd Generation EPS Range - No Inhibits Date: 11/10/2017 Page: 58 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK Switch on the simulated battery. Switch on the solar array power. Check that the system is operational (all power buses at expected voltages). Once this has been set up it is possible to test all functions of the EPS. For more detail on the individual tests performed on the EPS, refer to the test report which includes test setups and processes. Figure 12-4 Testing a standalone EPS 25-02452. Refer to Section 8 for connection of solar array connection when testing 25-02451 or 01-02453. 12.3 Testing with Clyde Space Battery Refer to User manual: 3rd Generation Battery Family (USM-1192), Section 13 Test for testing with a Manned Flight/ISS Compatible battery. SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 User Manual: 3rd Generation EPS Range - No Inhibits Issue: D Date: 11/10/2017 Page: 59 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK 13. COMPATIBLE SYSTEMS Compatibility Stacking Connector Notes CubeSat Kit Bus Clyde Space Battery Systems As listed in section 13.1. Other Batteries Please contact Clyde Space Clyde Space 2-3 cell solar array Connects to SEPIC BCR(s) Clyde Space 4-8 cell solar array Connects to Buck BCRs (not 25-02451) Other array technologies Please contact Clyde Space Clyde Space CubeSat 1/2/3U standard structure Batteries Solar Arrays Structure Pumpkin ISIS Other structures Please contact Clyde Space Table 13-1 Compatibilities SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved. USM-1335 Issue: D User Manual: 3rd Generation EPS Range - No Inhibits Date: 11/10/2017 Page: 60 of 60 Skypark 5, 45 Finnieston Street, Glasgow G3 8JU, UK 13.1 Compatible Batteries Standalone Batteries This EPS is expected to be integrated with one of the following Clyde Space battery products. It is not compatible with Clyde Space 3G No Inhibits or 2G battery ranges. Battery 10Wh Standalone Manned Flight 20Wh Standalone Manned Flight 30Wh Standalone Manned Flight 40Wh Standalone Manned Flight Product Code 01-02683 01-02684 01-02685 01-02686 Figure 13-1 Standalone Battery Compatibility Integrated Batteries The 1U EPS (25-02451) is also compatible with the following integrated batteries – the battery will be integrated onto the EPS as a daughterboard, rather than having a separate PC104 header. These are not compatible with the 3U or FlexU variants. Battery 10Wh Integrated Manned Flight 20Wh Integrated Manned Flight Product Code 01-02681 01-02682 Figure 13-2 Integrated Battery Compatibility SOLUTIONS FOR A NEW AGE IN SPACE PROPRIETARY & CONFIDENTIAL INFORMATION www.clyde.space Copyright ©2017 Clyde Space Ltd. All rights reserved.
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