The University of Skövde, in close collaboration with IDC and industry partners such as Volvo Cars, Aurobay, Volvo Penta, and Volvo GTO, has developed a new power electronics lab within the ASSAR collaboration arena. Stefan Ericson, senior lecturer in electrical engineering at the University of Skövde, serves as the lab's chief engineer, with full technical responsibility. “The new lab focuses on testing power electronics, especially in the electric drivetrain,” he explains. The initiative is part of a broader consortium effort supported by Västra Götalandsregionen (VGR), aimed at building and sharing knowledge related to manufacturing processes.
The Need for an Upgrade: Supporting Diverse Research Needs
The decision to upgrade the lab was driven by the need for a more modular and flexible testing environment to keep pace with evolving power electronics technology. According to Stefan, “One of the criteria when we built the lab was that it should be modular and reconfigurable. That means that if the test object changes from inverter to onboard charger or to DC/DC converter, the lab should be able to handle that.” The lab is designed for 30kW but can be easily expanded to accommodate higher power levels. This upgrade ensures that the lab can support a variety of research projects tailored to the specific needs of the manufacturing companies involved.
New Equipment: Advanced, Flexible, and User-Friendly
To meet these ambitious goals, the lab was equipped with a variety of high-performance instruments selected for their precision, flexibility, and cost-effectiveness.
Power Supplies and Loads
“We needed power supplies to simulate a vehicle's DC bus. The modules had to be bidirectional and regenerative, so they can act as battery simulators when testing inverters,” Stefan says. The lab uses Delta Electronics power supplies known for their reliability, ease of use, and excellent performance at a competitive price point. Additionally, EA power supplies were selected for their advanced features. A narrower AIM-TTI power supply, though not bidirectional, is used as an auxiliary supply offering multiple voltage outputs and a network interface that simplifies control. For loads, the lab uses DC loads capable of simulating conditions for onboard chargers and DC/DC converters.
Measuring Instruments
The oscilloscope is described as the “most important instrument in the lab.” The team selected Tektronix oscilloscopes with 8 channels operating at 500 MHz, equipped with advanced optical probes ideal for performing double pulse tests critical in power electronics research. A notable feature is the ability to upgrade the oscilloscope's frequency via software, supporting the lab's need for reconfigurability. For spectrum analysis, a compact USB-based Tektronix spectrum analyzer is employed to “sniff the air” for manufacturing errors without requiring a full-scale spectrum analyzer. Power analysis is handled by Hioki power analyzers, chosen for their modularity, flexibility, and straightforward efficiency measurements. Additional Hioki instruments include handheld multimeters, Hi-Pot testers, LCR meters, and micro-ohmmeters, essential for safety testing and detailed electrical characterization.
Data Acquisition and Control
The lab relies on National Instruments (NI) hardware for data acquisition and control. Systems like compactDAQ and compactRIO provide a flexible platform compatible with multiple software environments including LabVIEW, Matlab, and Python. Stefan highlights LabVIEW's capabilities: “LabVIEW is outstanding for creating GUI and supports most instruments that we bought,” enabling the team to build customized test setups easily. The lab also integrates a specialized module for simulating resolver signals, which requires compactRIO hardware, reflecting the lab's focus on realistic electric drivetrain testing.
Collaboration with CN Rood: Expertise and Flexibility
A key factor in the success of the lab upgrade has been the collaboration with CN Rood, a partner who enabled the team to build their own flexible test system rather than relying on a turnkey solution. Stefan remarks, “CN Rood provided us with their expertise to guide us for right selections,” and he praises their approach: “We get a system that is flexible and that we are in control of. We are not dependent on the supplier to modify or change anything and there is no proprietary software that locks us out.” This partnership has been both cost-effective and empowering, providing the lab with superior capability and performance. Stefan concludes, “CN Rood is the reliable partner that made the difference for us!”
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