A Highly Dynamic 600 V / 300 A Battery Emulator for Testing of Automotive Electric Drive Trains

In this paper, a highly dynamic 80 kW battery emulator for test bench applications is proposed. The novelty is the accurate battery impedance emulation for frequencies up to 20 kHz. This allows for a reproduction of parasitic oscillations between battery and device under test as well as an emulation of voltage ripples due to switching frequency and motor harmonics.To identify the requirements, a common battery behavior was analyzed in the frequency domain. The result was applied for adapting not only the performance of the control strategy but also for adapting the hardware of the emulator.To achieve accurate battery emulation, a design of two serially connected switching converters with different power rating and dynamic behavior, an LC filter optimized regarding the output impedance, and a physical interface for emulating the parasitic inductance of the battery was adapted. For the control strategy, a full state feedback controller that replicates the battery resistance by choosing appropriate poles was used.Simulation results are given to show that sub-millisecond oscillations can occur between battery and electric drive system and that the proposed emulator achieves almost ideal representation of the battery model when used in this application.