European Conference on Nanoelectronics and Embedded Systems for Electric Mobility emobility emotion 25-26 th September 2013, Toulouse, France Functional Validation of Battery Management Systems Christian Niklas AIT Austrian Institute of Technology, Austria
Outline Introduction Safety-related BMS-Functions HIL-Testbench Approach Challenges in Testing BMS HIL-Simulation Setup for CAN and SPI Networks Conclusion 2
Introduction Battery Management Systems objectives Ensure safe operation Battery diagnostics Communication Vehicle Control Unit (VCU) On-board charger/charging equipment (OBC) ECU VCU GW OBC + BMS - MCU 26.09.2013 NESEM Conference, Toulouse 3
Safety-related BMS Functions BMS safety goals Follow switch-off/on request from the charging device Related BMS functions Charging request monitoring Vehicle-CAN communication Relay control 4
Safety-related BMS Functions BMS safety goals Follow switch-off/on request from the charging device Overcharge of battery cell(s) shall be avoided Related BMS functions Charging request monitoring Vehicle-CAN communication Relay control Battery current monitoring 5
Safety-related BMS Functions BMS safety goals Follow switch-off/on request from the charging device Overcharge of battery cell(s) shall be avoided Over-temperature of battery cells shall be avoided Related BMS functions Charging request monitoring Vehicle-CAN communication Relay control Battery current monitoring Temperature monitoring Thermal management Battery module communication 6
Safety-related BMS Functions BMS safety goals Follow switch-off/on request from the charging device Overcharge of battery cell(s) shall be avoided Over-temperature of battery cells shall be avoided Over/Under-voltage of battery cells shall be avoided Related BMS functions Charging request monitoring Vehicle-CAN communication Relay control Battery current monitoring Temperature monitoring Thermal management Battery module communication Voltage monitoring 7
Safety-related BMS Functions BMS safety goals Follow switch-off/on request from the charging device Overcharge of battery cell(s) shall be avoided Over-temperature of battery cells shall be avoided Over/Under-voltage of battery cells shall be avoided Open contactors in case of an isolation fault Related BMS functions Charging request monitoring Vehicle-CAN communication Relay control Battery current monitoring Temperature monitoring Thermal management Battery module communication Voltage monitoring Isolation monitoring 8
Sensor System Allocation Safety-related BMS functions Charging request monitoring Relay control Battery current monitoring Voltage monitoring Temperature monitoring Thermal management Isolation monitoring On-board Charger Battery Management System vehicle CAN Battery Modules sensor network (SPI / CAN) I/O Power Distribution Module Isolation Monitoring Module Cooling System 9
HIL-Testbench Approach Benefits Safe testing environment Automated tests Flexible design Reproducible test results No cell emulators needed Limits Initialization timing Quality of validation relies on the accuracy of the battery model virtual subsystem Power Distribution Module simulated bus Battery Modules On-board Charger Isolation Monitoring Module simulated bus physical bus Cooling System real subsystem Battery Management System I/O physical bus I/O 10
Challenges in Testing BMS Full-size virtual battery simulation Simulation of complete cell string Balancing behaviour Realistic thermal behaviour Sensor network simulation Interfacing the BMS on the used sensor network for battery module communication (SPI / CAN) Data refreshment timing Vehicle network Remainig-bus simulation on vehicle network Interfacing the EVSE 11
HIL-Simulation Setup for CAN Networks Simulink model of a battery cell «Test Scenarios «Model Execution «Report Generation Simulink Model Matlab/Simulink Battery Modules simulated battery internal bus HIL Interface CAN I/O CAN Power Distribution Module Isolation Monitoring Module Cooling System Embedded Code Embedded Code Embedded Code CAN sensor network vehicle CAN bus I/O 12
HIL-Simulation Setup for SPI Networks Simulink model of a battery cell «Test Scenarios «Model Execution «Report Generation Simulink Model Matlab/Simulink Battery Modules simulated battery internal bus HIL Interface Ethernet I/O CAN Power Distribution Module Isolation Monitoring Module Cooling System Embedded Code Embedded Code Embedded Code Ethernet vehicle CAN bus I/O Balancer Emulator SPI 13
Balancer Emulator Objective Instantiation of several balancer chips Addressable via slave select and/or configured chip address Real response time Balancer Emulator x Instances HIL Interface Theory of Operation (1) Balancer emulator requests cell voltages update (2) Addressed instance requests data refreshment from HIL (3) HIL simulation calculates new values and transmits it to the emulator (4) Balancer instance responds to BMS command with new data (1) (4) busy ensure real response time behaviour new data (2) (3) 14
Conclusion Functional Validation of Battery Management Systems in a safe and affordable manner leads across the simulation of the battery internal communication network Solution provides support for SPI and CAN Still no need to invest in expensive Cell emulators No limitation for Smart Charging simulations via PLC to address V2G applications 15
Thank you for your attention Contact Christian Niklas Austrian Institute of Technology Electric Drive Technologies Vienna Austria christian.niklas@ait.ac.at www.ait.ac.at