Structures and modulation algorithms of direct ac/ac converters with two legs and three legs for two‐phase systems

Abstract

AbstractTwo‐phase ac/ac matrix converter configurations are presented based on direct power conversion processes from three‐phase input ac supplies to two‐phase output ac loads. Two types of two‐phase matrix converter topologies, utilizing the standard matrix converter configuration, are introduced with two‐leg and three‐leg based structures. Pulse width modulation (PWM) strategies with high‐frequency composition for the two‐leg and the three‐leg based two‐phase matrix converters are developed to synthesize sinusoidal output waveforms of two‐phase loads from time‐varying input ac voltages. Grounded on the developed modulation algorithms, the presented matrix converters directly generate controllable two‐phase output voltages from sinusoidal input voltages with no intermediate dc conversion and concomittant dc‐link elements. The proposed matrix converters can provide sinusoidal output current/voltage waveforms with independently controlled magnitude and 90° phase angle to two‐phase loads. Thus, the converters are effective for both balanced and unbalanced two‐phase loads. The presented two‐phase operations with the standard matrix converter structures add the versatility for the matrix converter systems to function in multi‐phase loads as a universal converter. Simulation and experimental results are presented to verify the developed modulation techniques and the converter configurations for the two‐phase matrix converters. Copyright © 2009 John Wiley & Sons, Ltd.