Electric machine emulation (EME) is becoming a popular solution in advanced testing and validation of power-electronics-based machine drive systems. In terms of a typical EME, the stator current references are first calculated in response to the sampled terminal voltage, and then, are electrically generated by power electronics converters. In this type of structure, closed-loop current control and low-pass sampling for the voltage are inevitably introduced, resulting in distortion in frequency-domain behaviors of EME. Consequently, the steady-state performance under a high fundamental frequency, and the dynamic performance under load transients, may deviate from those of the target machine system. In this article, the bandwidth limitations of the typical EME are identified and analyzed in detail, and a novel structure that realizes full-bandwidth mission profile emulation is proposed. Theoretical analyses are given to prove that the frequency-domain characteristics of the proposed structure would be identical to the actual machine systems, which allows for the extended operating range of mission profile emulation. Simulation and experimental results are provided to validate the effectiveness of the proposed method.

Published in: IEEE Transactions on Power Electronics ( Volume: 37, Issue: 3, March 2022)