Improved Accuracy of Power Electronic-Based Motor Emulation With Compensation for Signal Transmission Delay

The power electronic-based motor emulator (ME) has shown the prospect of replacing the mechanical back-to-back dynamometers with a power converter to validate the performance of the inverter under test (IUT). In real application of the ME to test the IUT, the controller of the IUT is independent of the ME so that there are time delays caused by the input voltage sampling of ME, ME calculation, and the position signal transmission. Such a delay will cause cross coupling between the
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-axis, which severely influences the emulation accuracy, especially under higher emulated motor speed. A compensation method is proposed to eliminate the cross coupling. A prototype is designed, and simulation and experiment results are provided and compared to that of the normal ME to verify the compensation effect. The experimental results have shown that the proposed compensation method can improve the emulation accuracy, and a wider speed range of the motor can be emulated accurately.