Deville's test team currently works with three Speedgoat HIL test systems. Compared to the previous setup, they can now test either single or multiple fuel cell components together. "The young engineers in our team can perform everything they want. The setup is versatile. We don't have to develop many tools to do what we want. It's really out-of-the-box from our point of view," Deville explains. The team makes sure each component works properly before carrying out expensive system-level tests.
The team started with a HIL system to test the main electronic control unit (ECU) that controls the chemical reaction of the fuel cells. They modeled sensors, inverters, compressors, and other embedded components to simulate them when testing the ECU. The fuel cell has since received a safety release compatible with open road authorization. "The HIL test system represents now a major activity in open road approval. There is a good level of trust at Symbio and the customer about what we can do with it."
Following the first steps with the HIL setup that still involved manual test work, they introduced the first automated test campaign and soon hit a major milestone within a few months. "Doing something once could be great, but if you performed the same test every week, the manual work could become repetitive," Deville explains. He adds: "The way we can automate testing is a great enabler for us."
In early 2025, the team started to test compressors, DC-DC converters, and fuel cell monitors (similar to a battery management system) with a power HIL setup. "The purpose of power HIL is to ensure that all components work together at the actual power level before proceeding with the system testing," Deville explains. Currently, they are able to test up to 800 V on the battery side and to simulate fuel cell power behavior at 230 A and 300 V.
Thanks to the power HIL test system, they can now test multiple components thoroughly to ensure that everything runs safely together at actual power levels before the field tests. "Power HIL is the great enabler this year," summarizes Deville. In the future, they want to connect as many components as possible and validate them through simulation as if they were in the vehicle itself.
In addition to HIL and power HIL testings, the Symbio team plans to conduct field test replays, which generate extensive data and help uncover issues requiring control logic updates. "Now we can take this data and replay it directly on the HIL test bench and make sure that the issue will not occur again after the software update."