PWM Method of Matrix Converter for Reducing Output Current Ripple

摘要

This paper presents a new PWM method using a virtual DC-link voltage concept for reducing output current ripples. Matrix converter is interfaced with three phase AC voltage source. And the AC source makes three different level virtual DC-link voltages. In this paper, a generalized PWM method is proposed to use these three virtual DC-link voltages. In the case of using higher two line to line voltage as virtual DC-link, the proposed method is exactly identical with the conventional SVPWM method. Moreover, the proposed method is able to select the virtual DC-link according to the PWM purposes and/or load condition. Selecting the virtual DC-link which is adjacent to the output voltage reference, the output current switching ripple can be reduced. The feasibility of the proposed PWM method is verified by a computer simulation and experimental results. The output voltage and current of the proposed method can be identical with that of the conventional SVPWM method. Moreover, a new switching sequence to reduce the output current switching ripple can be easily adopted. Compared with the output current of the conventional PWM method, the harmonic characteristics of the proposed method can be significantly improved.