Output Waveform Improvement of Single-Phase to Three-Phase Matrix Converter for High-frequency Applications using Delta-Sigma Modulation and Space Vector Modulation

Abstract

This paper discusses pulse density modulation (PDM) control methods for a single-phase to three-phase matrix converter (MC) in high-frequency applications. The proposed circuit is used as an interface converter for a wireless power transfer system. This converter can input a frequency of several hundred kilohertz and output a low frequency, i.e. 50Hz or 60Hz, for commercial power grids. The proposed circuit achieves zero voltage switching operation by using the PDM control method and obtains high efficiency. In this paper, two PDM control strategies are compared: PDM control based on space vector modulation (SVM) (the conventional method) and the proposed PDM method, which combines SVM and delta-sigma modulation. Also, the experimental results of the proposed system will be demonstrated and discussed. As a result, the total harmonic distortion (THD) of the output voltage with the conventional method and the proposed method are 9.05% and 1.87%, respectively, when the modulation ratio is 0.5. Thus, the validity of the proposed method has been confirmed for improvement of the output waveforms.