Active PWM Synchronization With ON-OFF-State Information of Power Semiconductors in Mission Profile Emulation Test

In a power-electronics-based mission profile emulation (MPE) system, the converter under test (CUT) and the emulating converter are typically powered by the same dc voltage source for high efficiency. This also inevitably creates a circulating path for common-mode current ripples, which will cause sampling distortions and control errors. The current ripples have not been adequately addressed in the existing literature on the MPE. Typically, the common-mode current ripples can be suppressed by common-mode chokes. However, the amplitude of the common-mode current ripples fluctuates with the difference between the carriers of the CUT and the emulating converter, burdening the common-mode choke. The carrier difference can be fixed by synchronizing the carriers of the CUT and the emulating converter. However, conventional synchronization methods require modifications to the CUT, which changes its characteristics and prevents the MPE system from being plug-and-play. In this paper, an active PWM synchronization method with ON-OFF-state information of devices in the CUT is proposed. The carrier of the CUT can be reconstructed without modifications to the CUT. Then, the carrier of the emulating converter can be synchronized with the reconstructed carrier to minimize common-mode current ripples. This, in turn, reduces the burden on common-mode chokes and the volume of common-mode chokes. Besides, the control structure of the emulator remains unchanged, and the emulator can achieve a plug-and-play feature. Experimental results are provided to validate the effectiveness of the proposed method.