Efficient Power Electronic Inverter Control Developed in an Automotive Hardware-in-the-Loop Setup 2019-01-0601

Hardware-in-the-Loop is a common and established testing method for automotive developments in order to study interactions between different vehicle components during early development phases. Hardware-in-the-Loop setups have successfully been utilized within several development programs for conventional and electrified powertrains already. However, there is a particular shortage of studies focusing on the development of inverter controls utilizing Hardware-in-the-Loop tests. This contribution shall provide a first step toward closing this gap. In this article, inverter controls with different pulse width modulations for varying modulation index are studied at a Hardware-in-the-Loop setup. Thereto, the inverter control for an interior permanent magnet synchronous machine is developed utilizing space vector pulse width modulation with overmodulation. The starting point for the inverter control implementation includes power and loss analyses for the power electronic inverter as well as for the interior permanent magnet synchronous machine at a laboratory test bench. Comparing space vector pulse width modulation with and without overmodulation, it is determined that the system losses are reduced by 9 % and the power is increased by 8 %, which verifies the performance improvement by applying overmodulation. In addition, a real-time vehicle dynamics simulation of a battery operated electric powertrain is developed. The required driving resistance parameters for the vehicle dynamics simulation are verified based on defined vehicle coast down test results. The vehicle dynamics simulation is combined with the inverter control and the test bench components to a Hardware-in-the-Loop setup complying with real-time conditions. The power of the interior permanent magnet synchronous machine is increased by virtual scaling of its active length, which demonstrates the testing variability of the Hardware-in-the-Loop setup. This modified electric powertrain and the newly developed inverter control are tested in the class 3 worldwide harmonized light vehicles test cycle. The interactions between the inverter control and the electric powertrain are analyzed and the results are discussed. Moreover, the Hardware-in-the-Loop methodology’s ability to accelerate the development process for automotive applications is demonstrated.