Two-step Commutation for Three-phase-to-single-phase Matrix Converter with High-frequency Isolation

Abstract

This paper proposes a two-step commutation method for a three-phase-to-single-phase matrix converter. Conventional two-step commutation cannot be applied at all operation regions because a commutation failure still owing to detection error of grid voltages. In our proposed two-step commutation, we modulate only one of two devices in a bidirectional switch and utilize a zero vector to let the switches naturally turn off, in this manner, the commutation failures are avoided completely regardless of the voltage detection error. From experimental results, it is confirmed that the proposed two-step commutation undertakes safe operation to avoid commutation failure. The input current total harmonic distortion at 10kW with the proposed two-step commutation is improved by 38% in comparison with the conventional four-step commutation.