Matrix converter topologies with reduced number of switches

Abstract

A direct AC-to-AC converter commonly termed a matrix converter has a simple structure and many attractive features. However, the complexity of its conventional PWM strategy is prone to commutation failure, which is a factor that keeps it from being utilized in industry. This paper focuses on several alternative dual-bridge matrix topologies which do not possess this problem. First, these converters have the same characteristics as a conventional matrix converter, such as four-quadrant operation, unity input power factor, no DC-link capacitor, and high quality voltage/current waveforms. Second, the number of switches can be reduced thus reducing the cost. Third, the switches on the line side can turn on and off at zero current, they do not have any difficult commutation problems. Lastly, the complexity of the clamp circuit in these topologies can be greatly simplified thereby further reducing the cost. This paper introduces several topologies with a reduced number of switches and analyzes the characteristics of this converter family. Simulation and experimental results of a 9-switch topology are provided to verify its feasibility.