Customers approach VISPIRON SYSTEMS with a wide variety of inverter types, applications, and requirements – ranging from traction inverters for automotive use to other power electronics domains. For a testing service provider, this raises a strategic question: How can such diverse and highly dynamic inverters be tested efficiently without having to build a dedicated test bench for every new request?

In an automotive project focused on traction inverter testing, VISPIRON SYSTEMS addressed this challenge with a power hardware-in-the-loop (HIL) approach for testing high-voltage power electronics. Power HIL testing combines real voltages and currents with model-based simulation, enabling realistic validation without a rotating machine test bench. The key advantage is not only realism, but also adaptability: By changing models and parameters instead of redesigning the underlying infrastructure, the same hardware can be quickly configured for different inverter types, customer requirements, and development stages.

Why Conventional Test Setups Reached Their Limits

“For VISPIRON SYSTEMS, the need for a new testing approach arose from the growing complexity of inverter projects”, explains Michael Kressierer, Head of Laboratory Power Electronics at VISPIRON SYSTEMS. He continues: “Each request brings new parameters, interfaces, and operating conditions that must be considered.” Conventional machine test benches are typically designed for specific use cases and often require significant effort to adapt them to these varying requirements.

Meanwhile, validation is expected to start earlier in the development process, when only limited system data is available. VISPIRON SYSTEMS therefore aimed to create a modular test platform for current and future traction inverters that enables early testing, realistic e-machine emulation, and fast switching between variants with minimal effort.

Balancing Flexibility and Precision

This objective led to several key requirements for the new test system. In addition to achieving broad test coverage, the system had to:

• Support a range of inverter variants and maturity levels, including advanced technologies such as three‑level inverters
• Provide realistic electric machine emulation with highest precision for different machine types
• Meet standards-based requirements as defined in common standards for electrical components in electric vehicles, including LV 123, LV 124, and ISO 21498
• Enable testing of inverter behavior under dynamic and worst-case operating conditions

VISPIRON SYSTEMS also required a modular architecture that can be easily extended to additional use cases such as onboard charger testing. The availability and quality of input data presented another challenge. “Even in early development phases, when detailed system information is still incomplete, meaningful tests to identify potential issues early must already be possible”, reports Michael Kressierer.

Implementing the Test Environment

The setup provides the real-time performance and flexibility required for power-level testing. Within this environment, the electrical behavior of the surrounding system is emulated at the power interfaces, enabling realistic inverter validation under dynamic conditions. Electronic loads replace both the motor and the battery for a realistic power flow.

On the software side, FPGA-based real-time models define the electrical behavior at the power interfaces. Here, VISPIRON SYSTEMS uses high-precision dSPACE simulation models from the XSG Electric Components Library and the Generic Drive Models (GDM). These FPGA-based models enable the real-time simulation of various machine types and electrical characteristics with high dynamics and precision. The models are parameterized using motor data derived from measurements or datasheets.

“The dSPACE test system integrates electrical behavior, sensor signals, and customer-specific communication interfaces within a unified environment. This combination of real power, configurable simulation models, and parameterization enables consistent and realistic inverter testing across different applications”, emphasizes Michael Kressierer.

Evaluating the Power HIL System

For VISPIRON SYSTEMS, the new power HIL system represents a fundamental extension of its testing capabilities. “While conventional setups with active loads could not accurately emulate electric machine behavior, the power HIL approach enables realistic machine emulation under dynamic conditions”, states Michael Kressierer.

He concludes: “In the new test environment, the team can validate traction inverters earlier in development across a wide range of scenarios. Even with limited input data, testing can start early and be refined as the project progresses.” At the same time, the open and parameterizable dSPACE models support fast adaptation to different requirements while maintaining high precision. As a result, VISPIRON SYSTEMS is now able to easily extend its testing services to a wide range of applications.

Outlook

Looking ahead, VISPIRON SYSTEMS will further expand the capabilities of its power HIL test environment. Key priorities initially include extending test automation, building larger automated test catalogs, and moving from component-level to integration testing. Furthermore, the approach aims to incorporate additional inverter types and power electronics applications across a broader range of industries beyond the automotive sector. Future developments may also include:

• Remote access to the test system as part of the testing-as-a-service offering
• Shifting function development and controller design from dynamometer-based to power HIL testing
• Integrating new devices under test, such as DC charging stations

Overall, the platform is intended to grow in both scope and functionality, strengthening its role in advanced power electronics testing.

 

Courtesy of VISPIRON SYSTEMS

dSPACE MAGAZINE, PUBLISHED JUNE 2026