1. Battery Management System (BMS)
HIL Test
B CHANDRA SEKHAR
Senior Software Engineer
MaxEye Technologies
2. Contents
• HIL System and Components
• Battery Management System
• BMS HIL Test System
• BMS HIL System Architecture
• HIL System Hardware & Software
• Conclusion
3. HIL System
• Safety, cost and reliability are the considerations that make it impractical to test
embedded system in real world.
• HIL testing is a technique for testing embedded control systems, by simulating the
real world signals/scenarios that would mimic the real plant.
• Testing in a virtual environment would maintain the reliability and time to market
requirements in cost-effective manner before proceeding to real-world tests.
4. Components of HIL
• HIL system consists of three main components: Real-time processor, I/O interface
and Operator interface.
5. Components of HIL
• HIL system with FIUs(Fault Insertion Units) to create faults between UUT and rest
of the system such as short-to-ground and open-circuit.
6. Components of HIL
• HIL system with multiple processors provided with timing and synchronization to
test multi ECUs.
7. NI Platform is Open &
Extensible
Scalable software
Modular Architecture, so
upgraded with additional
functionality
NI SW tools to help automate
HIL tests
Perform post-processing and
analysis
Requirements tracing
Report generation
8. BMS (Battery Management System)
• BMS is an embedded unit performing critical battery functions.
• Cell voltage monitoring and balancing, pack charge and discharge control
• Cell temperature monitoring and control
• Protection and safety management, Increasing life time
10. Additionally, a BMS may compute:
● Maximum charge current as a charge current limit (CCL)
● Maximum discharge current as a discharge current limit (DCL)
● Energy [kWh] delivered since last charge or charge cycle
● Charge [Ah] delivered or stored
● Total energy delivered since first use
● Total operating time since first use
● Total number of cycles
11. Cell, Module and Pack
When a number of cells are put into a frame then this is called a module which includes cells, and the
interconnects which provide electrical conductivity between them. Rechargeable battery packs often contain a
temperature sensor.
12. Battery Pack Architecture
When a number of modules come together with a BMS (Battery Management System) and a cooling device
that control and manage battery’s temperature, etc., this is called a pack.
The battery pack and internal block diagram is shown below:
13. BMS Communication
The central controller of a BMS communicates internally with its cell level hardware, or
externally with high level hardware such as laptops or HMI. High level external
communication use several methods:
● Different types of Serial communications.
● CAN bus communications, commonly used in automotive environments.
14. BMS Functions to Evaluate
• Cell/Module/Pack balancing
• Fault conditions (Short/open circuit, polarity change)
• Over voltage/current/temperature
• Under voltage/current/temperature
• State of Charge Estimation
• State of Health Estimation
• BMS behaviour under different temperature conditions
• BMS behaviour under different charge/discharge cycles
• Communication behaviour and failures
15. BMS HIL Test System
• Hardware in Loop simulation is the best approach for BMS algorithm development
and testing.
• It utilizes the cell model, battery cell simulator, FIUs, temperature simulation,
automated test software to test BMS in real time.
• Simulates the entire battery system, including cells, temperature sensors, pack
current, contactors, and digital communications
• Simulates imbalance, drive profiles, charge/discharge cycles, thermal runaway and
other faults in real time
19. HIL System Hardware
The HIL System consists of NI PXI
chassis, RT-Controller, Digital &
Analog IO module, Communication
protocol modules.
Battery Cell Simulators, Fault Insertion
Units, Temperature Simulation for
simulating the cell voltages, faulty
conditions and temperature simulations
21. Battery Cell Simulator
Isolated channels to simulate source and sink
characteristics
12 independently controlled channels
Cell supply range 0.01 … 8V up to 5A
Supports both active and passive balancing
Current measurements up to +/- 4.9A
Integrated failure simulation to support short/open
circuit, polarity reverse, line brake simulation
Communication via CAN/EtherCAT 100Mbit/S
Supports up to 200 cells in total
23. HIL System Software
The automated system software is based
on NI TestStand to manage the test
system. NI VeriStand to run the
cell/pack models in real-time on RT
engine.
The software provides the configuration
and execution of tests, custom stimulus
profiles as well as manual control.
The speed of FPGA and flexibility of
NI LabVIEW meets the system
specifications and performance.
24. Conclusion
• The BMS HIL System delivers a flexible test platform that facilitates rapid design
and testing of the BMS firmware, thereby accelerating development of hybrid and
fully-electric vehicles.
• A hardware-in-the-loop (HIL) test platform based on NI PXI, Communication & IO
modules, LabVIEW software, TestStand software, VeriStand software, DIAdem
software and Battery Cell Simulator to simulate a cell advanced-chemistry, fault
simulations for hybrid and electric-vehicle applications.
• MaxEye provides BMS test systems covering the full BMS development life cycle,
from initial design and prototyping of hardware and firmware, comprehensive
validation of environmental and performance specifications, as well as end-of-line
manufacturing test.