Electric vehicle (EV) architectures are advancing toward the 800-V class and beyond, which is reshaping how engineers test batteries, inverters, converters, and high-performance compute subsystems.
Jeff Brakley, Senior Product Manager at AMETEK Programmable Power
These systems now require power platforms that can operate bidirectionally, regenerate energy, and accurately emulate real-world load dynamics under an extensive range of conditions.
To discuss how these shifts are influencing validation workflows, we spoke with Jeff Brakley, Senior Product Manager at AMETEK Programmable Power, a global supplier of programmable ac and dc power sources, electronic loads, and test solutions for automotive, aerospace, and industrial applications.
In this Q&A, Brakley shares where testing requirements are heading and what engineers should expect as EV system voltages and power levels continue to rise.
Here’s what he has to say…
As EV battery voltages climb to 800 volts (V) and higher, what new testing and validation challenges arise at the cell and pack levels?
Jeff Brakley (JB): EV battery voltages are climbing from 400 to 800 V and beyond. Some material handling and construction equipment applications are going to 1500 V. The key benefit of higher voltages in these applications is that they reduce the size (gauge) of the conductors, lower system weight, and enable faster charging times.
Testing battery packs at these higher voltages requires test equipment that has equivalent voltage and power ratings. Bidirectional and regenerative programmable power supplies have evolved to meet these requirements and are now being used to test these high-voltage batteries.
How do real battery tests differ from battery emulation, and when is each most useful in EV development?
JB: Testing real battery performance is required to ensure that the battery meets its intended design objectives to accept and release charge to power the EV over its lifetime. Extended testing is also required to ensure that rigorous drive cycles meet or exceed industry or manufacturer standards.
Emulation comes into play to test other EV components, such as dc motors EV charges and other drivetrain components without have to rely on the battery itself. Having one piece of test equipment that manages all these requirements in research and development enables a smooth transition to production test without additional investment.
Programmable power enables testing across the entire EV ecosystem, including batteries, BMSs, traction inverters, onboard chargers, and fast-charging infrastructure, as illustrated in this system overview.
How do programmable bidirectional systems shorten battery validation timelines compared to conventional hardware setups?
JB: Programmable, bidirectional and regenerative test systems typically have all the capabilities required to perform multiple tests in one box. Before the advent of these new test systems, multiple pieces of equipment were required, such as a programmable dc power supply, programmable electronic dc load and high-power switching systems to manage all the required test scenarios.
These systems took additional time to setup and manage the connections which, ultimately, extended the test time.
How are engineers managing thermal control, current ripple, and measurement accuracy during high-power charge/discharge and lifecycle testing?
JB: Thermal control for the unit under test is typically managed by the device. However, the benefit of having a bidirectional and regenerative programmable dc power supply is found in the regeneration feature.
Older programmable dc electronic loads used for discharging batteries typically burned off that power as heat. This excess heat required additional cooling in the test lab or factory to maintain the environment, and that was a cost adder.
The Sorensen Modular Intelligent-Bidirectional Energy AMplified (Mi-BEAM) series from AMETEK is a bidirectional, regenerative dc supply designed for EV battery and subsystem testing.
The regeneration feature now returns 95% of that energy to the electric grid instead of wasting it as heat.
Regeneration lowers the cost of electricity to benefit other operations within the facility. Additionally, some multi-channel products reuse that energy internally, employing the discharge power from one battery to supplement the charge power for another battery.
Setting up test programs with this feature can also reduce the power requirement of the overall system for further savings.
How are test platforms evolving to replicate real-world dynamic load conditions from inverters, dc/dc converters, and vehicle drive cycles?
JB: Battery simulators must mimic batteries’ many different charging and discharging characteristics, which depend on battery chemistry, capacity, state of charge (SOC), and other conditions.
A suitable bidirectional dc power supply must be able to source and sink current and support standard or custom battery models that define characteristics. One significant differentiator between a bidirectional dc power supply and a battery simulator is the presence of a series resistance.
What additional considerations come with bidirectional or regenerative operation, including isolation, source-to-sink transitions, and grid interaction, and how are they verified?
JB: As the EV market evolves, test challenges extend from grid-connected chargers and vehicle-to-grid (V2G) equipment to vehicle high and low-voltage batteries, and from the power semiconductors in traction inverters to the high-performance computing (HPC) and automated driver assistance system (ADAS) processors critical to performance and safety.
Validating high-voltage charging systems demands programmable power sources and battery simulators that can replicate real charging conditions.
Programmable power has a central role in testing all aspects of EV performance, ensuring that all components work together under a wide range of operating voltage and current conditions.
An effective power supply used in this application should also include a list/waveform-generation function that enables it to generate sequences of voltage and current ramps with programmable start, dwell, and stop times to support a variety of drive-cycle tests.
Having a seamless transition between source and sink operation enables transient response times of less than a millisecond to further validate real world conditions.
Other features to look for in a bidirectional programmable dc power supply include software, datalogging, external inhibits, and safety capabilities to prevent damage to the unit under test and other equipment. It’s possible to develop your own test programs, but native software such as a graphical user interface (GUI) that brings the supplies from the panel to your computer screen can help you get up and running quickly, improve troubleshooting, and reduce time-to-test.
Filed Under: Featured Contributions, Power Electronics, Q&As