Power electronic transformer with reduced switch count and dual matrix converters to eliminate load common-mode voltage and input snubber requirement

Abstract

This paper presents a pulse width modulation (PWM) technique for a reduced switch count high frequency power electronic transformer (PET) with direct ac-ac power conversion using dual matrix converters. High frequency switching common-mode voltages produced by power electronic converters across a machine can cause bearing currents, leading to premature bearing failure. The proposed PWM method for the PET with dual matrix converters aims at eliminating common-mode voltages across the open-end winding load. Also, the proposed PWM method facilitates zero current switching (ZCS) of PET primary side switches, thus eliminating snubber requirements for these switches. In addition, using dual matrix converters instead of a single matrix converter (proposed in a previous paper) results in increased maximum output voltage to input voltage ratio.