Pumpkin EPSM1 User Manual

Hide thumbs

Table Of Contents

Table of Contents

Quick Links

Download this manual

UM-31

User Manual

750 Naples Street

•

San Francisco, CA 94112

•

(415) 584-6360 •

http://www.pumpkininc.com

EPSM1 User Manual

Specifications subject to change without notice.

last updated on Feb 12, 2023

All trademarks mentioned herein are properties of their respective companies

Table of Contents

Need help?

Do you have a question about the EPSM1 and is the answer not in the manual?

Questions and answers

Summary of Contents for Pumpkin EPSM1

Page 1: Epsm1 User Manual
San Francisco, CA 94112 • (415) 584-6360 • http://www.pumpkininc.com EPSM1 User Manual  Copyright 2019-2023 Pumpkin, Inc. All rights reserved. Specifications subject to change without notice. last updated on Feb 12, 2023 All trademarks mentioned herein are properties of their respective companies...
Page 2 User Manual TRADEMARKS The following are Pumpkin trademarks. All other names are the property of their respective owners.  Pumpkin™and the Pumpkin logo  Salvo™ and the Salvo logo  CubeSat Kit™ and the CubeSat Kit logo DISCLAIMER PUMPKIN RESERVES THE RIGHT TO MAKE ANY CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO CORRECT ERRORS AND IMPROVE RELIABILITY, FUNCTION, APPEARANCE OR DESIGN.
Page 3: Table Of Contents
User Manual EPSM1 User Manual ................... 1 CHANGELOG ..........................5 Purpose ............................6 Introduction ..........................6 Datasheet & Relevant Documents ..................6 PCBs ...........................7 PCB Details.........................7 Tips for Safe Operation ......................7 Warnings ...........................9 SupMCU........................10 FPGA..........................10 Connections ..........................11 Overvoltage Protection Shunt ..................11 SAIs..........................11 Simulating Solar Panels ..................13 Connecting Solar Panels ..................
Page 4 User Manual Dynamics & Limits ....................27 Example 1 ......................28 Example 2 ......................31 Output Block Fuses ....................34 UM-31 EPSM1 User Manual...
Page 5: Changelog
Added sections on SAI wiring, output block fuses, additional / new 20190915 images. Added example 2, showing battery charging as a function of available SAI 20191001 power. Improved status dump formatting. 20230212 Updated to reflect operation under recent firmware releases. UM-31 EPSM1 User Manual...
Page 6: Purpose
(commands, inputs, loads, etc.) are changing. Any electrical damage to the EPSM1 shall be assumed to have been done by the user, since the EPSM1 is tested at Pumpkin prior to delivery to an end-user. Such damage is not covered under warranty.
Page 7: Pcbs
 705-01723 for the power card  705-01576 for the lid card  705-01961 for the FPGA card The EPSM1 has at its core an SEU-immune MicroSemi FPGA, and multiple GaNFET-based dc/dc switching blocks. It also has a Microchip PIC24E MCU, running Pumpkin's SupMCU RTOS- based core software architecture, with EPSM-specific firmware extensions.
Page 8 SupMCU, via SCPI commands over I2C or the CLI. While there is no thermal convection in a vacuum, it's still a wise decision to operate the EPSM1 with a fan over it, in all situations (including stand-alone without being coupled to a structural heatsink).
Page 9: Warnings
User Manual Warnings Ring bus voltage is always present on the EPSM1, Warning even when the FPGA is disabled. The ring bus voltage will eventually collapse to 0Vdc only when all sources of input power are completely disconnected from the EPSM).
Page 10: Supmcu
SupMCU's CLI). cd ..; cd NVM; list FPGA The FPGA can be reprogrammed at any time when the EPSM1 is powered using a Pumpkin FPGA Programming Adapter 1 and a MicroSemi FlashPro4, with MicroSemi FPExpress software. FPGA reprogramming is normally only done at the factory, Note and not by end users.
Page 11: Connections
, ensure that this is the node PGND that is connected to system ground. SAIs The EPSM1's Solar Panel Inputs (SAIs) are distributed across four 10-pin connectors. SAI1-SAI4 are on the first two, and SAI5 and UM-31 EPSM1 User Manual...
Page 12 Each SAI input is connected to its own Warning SA_TLM +5Vdc pull-up resistor internal to the EPSM1. The voltage on all eight signals must remain below +3.3Vdc; failure to heed SA_TLM this will result in gross errors in the analog I/O functions (and some additional ones) of the EPSM1.
Page 13: Simulating Solar Panels
Do not reverse polarity on SAI inputs -- this can lead Warning to immediate damage to the EPSM1. The series resistor serves to enable confirmation of the EPSM1's MPPT operation. A single external power supply can feed all six SAIs, so long as a series resistor is used with every connected SAI input.
Page 14: Example Connection
Figure 4: Example solar cell string and temperature sensor, for SAI input Do not reverse polarity on SAI inputs -- this can lead Warning to immediate damage to the EPSM1. Example Connection In Figure 5 below, all six SAIs are being fed by solar panels simulated via an external power supply.
Page 15: Power Sequencing
The batteries can source or sink substantial currents Warning into and out of the EPSM1. Novice EPSM users may wish to current-limit attached batteries with series resistors or the like. The EPSM1 can be started from batteries alone. If/when there are no active SAI inputs present, all power will be sourced from the batteries, and no battery charging will occur.
Page 16: Epsm1 Subsystems
User Manual EPSM1 Subsystems Indicators The EPSM1 has four green status LEDs on the FPGA card, and one green status LED connected to the SupMCU. The FPGA LEDs are assigned to these functions:  Innermost: blinks regularly to indicate FPGA reads by the SupMCU ...
Page 17: Supmcu Firmware Version
Resets The EPSM1 normally ignores its external signal. This is -RESET normal for EPS operation, because the EPSM1 must be able to operate without interference from external reset signals, and because is an active-low signal whose value is ill-defined -RESET as power rails come up in a distributed system.
Page 18: Fpga Version And Temperature
AUX output, and perhaps also the battery blocks. Heat is generated by the end-to-end flow of high currents in the EPSM1 and spreads throughout the EPSM1, where it is measured via the FPGA and System temperature sensors.
Page 19: Wdt
The WDT is normally kicked via an I2C external command from an OBC-type host. The purpose of the EPSM1's WDT is to restart the entire system via an EPSM1 restart (and hence, a full-system power cycling) whenever the system's main computer / OBC is "in the weeds."...
Page 20: Solar Arrays
The EPSM1 will now restart after approximately 18 hours after the most recent kick of the WDT. At the next EPSM1 (re)-start, the WDT will be redefined to be the NVM value. commanded above, the new WDT value will not be written to NVM unless an NVM write operation is performed by the user.
Page 21: Batteries
User Manual 400mA. But all are under the maximum setting of 475 mA. Power into the EPSM1 as shown as positive power, and in aggregate, the six SAIs are converting approximately 39W of simulated solar power into ring bus energy to be used inside the EPSM1.
Page 22: Output Blocks
These passthroughs work only in one direction. An I2C master connected directly to a battery that is connected to the EPSM1 will not be able to read or write to the EPSM1 over I2C. Output Blocks Four Output Blocks are provided: 3V3, 5V0, 12V & AUX. They connect to the 104-pin bus connector.
Page 23: Fpga Rails
0xCC4 0)00:00:59:47.24 disp_data_analog: SNS_VUSB / AN10: 1734 1770 1799 0x2E0 0)00:00:59:47.25 disp_data_analog: -RESET / AN11: 3271 3277 3289 0xFFA 0)00:00:59:47.26 disp_data_analog: SNS_4096 / AN12: 4096 4096 4097 0x9FC Figure 14: Analog inputs in SupMCU status display UM-31 EPSM1 User Manual...
Page 24: Epsm Telecommand Interface
EPSM, and commands can be written to it. Telemetry The EPSM1's various voltages and currents and other telemetry items can be read through the usual telemetry reads supported by the SupMCU. EPSM status values are ready by the SupMCU at around 4Hz;...
Page 25: Bus
{bus_name},{ON|OFF} Disabling a bus effectively disconnects the relevant block from the EPSM1's ring bus. The voltage of a disabled bus will fall to 2- 3Vdc when there is nothing connected to it. Even a very small load -- on the order of 5mA or less -- can pull that disabled bus voltage to 0Vdc.
Page 26: Block Operation
(3V3, 5V0, 12V and AUX). The internal power required by the EPSM is relatively low (around 3W max). In a typical power deficit condition, the ring bus voltage collapses to a few volts. Depending on the state of the ring bus, the EPSM1's UM-31 EPSM1 User Manual...
Page 27: Dynamics & Limits
(25V - (0.475A x 5Ohms)) x 0.475A = 10.75W per SAI So, with a single power supply set to 25V and 5A, the EPSM1 will never draw more than 2.85A from this supply, and it can draw up to 64.5W from the solar array that the power supply is simulating...
Page 28: Example 1
64.5W -- neglecting losses -- will be routed to the battery in an attempt to charge the battery. If a load (e.g., on AUX) is also attached, then the EPSM1 will attempt to deliver to the load, and any remaining current will be used to charge the battery.
Page 29 EPSM1 sources or sinks occurs. Now, let's add a load to the AUX bus. Since a load is an unambiguous sink of current, the EPSM1 will react by drawing more current from its sources to provide power to the AUX bus.
Page 30 Figure 18: EPSM powering a load with battery In Figure 18 shows that in addition to powering the 1.7A load on AUX, the EPSM1 is also charging the battery to the tune of a 600mA charge current (denoted as -590, a current that is being sourced from the EPS).
Page 31: Example 2
SAIs in this case. Note also that the ring bus voltage has fallen further, in its asymptotic approach towards 32Vdc. Example 2 We begin this example with the EPSM1 idling, powered solely from BAT1, and with no load on AUX: 0)00:00:06:19.56 task_eps_dummy: ========================================================== 0)00:00:06:19.58 task_eps_dummy:...
Page 32 4096 4097 4097 0x9F9 Figure 20: EPSM1 Idling, BAT1, no SAIs, 500mA AUX load In this example, the maximum discharge current from the 16.8V BAT1 battery is set at 2000mA. In Figure 20, by inspecting the power values in the...
Page 33 0x9F8 0)00:00:21:13.58 task_eps_dummy: ========================================================== Figure 21: EPSM1 charging BAT1 with small AUX load, SAI voltage = 18V In Figure 21 we see that the power delivered to AUX has not changed, but now BAT1 is being charged, and is drawing 1460mA.
Page 34: Output Block Fuses
SAI current limits. This example illustrates how battery charging is dependent on available SAI power. Both SAIs and BATs power the EPSM1 itself, and any attached loads. The EPSM will balance overall power flow such that any available power left over after powering the 3V3, 5V, 12V and AUX buses, will be used for battery charging.
Page 35 In Figure 25, the load on AUX was reduced to 950mA, the AUX output has (automatically) recovered from the trip condition, and the fuse has been reset. The AUX output remained enabled through all of this example. UM-31 EPSM1 User Manual...
Page 36 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 0)00:00:07:28.80 task_eps_dummy: Total: +3371 -1092 -749 1530mW Figure 26: AUX block disabled, after fuse trip event UM-31 EPSM1 User Manual...