Direct Modulation of Matrix Converter With Optimized Switch Transitions

Abstract

The two most commonly used modulation schemes for conventional matrix converters are indirect and direct space vector pulse width modulation (PWM). The former is preferred due to its mathematical simplicity. But this simplicity comes at the cost of concealing some redundancies, which can be exploited to improve the output voltage waveform, suppress common mode voltage, and reduce switching losses. This article proposes a new modulation algorithm that eliminates the redundant states of the direct space vector PWM. This novel algorithm eliminates the need for the zero vector and specific active vectors over a wide range of operating conditions, leading to improved output THD and lower switching losses. A rigorous mathematical analysis is performed and validated with a 5 kW laboratory prototype.