Enhancing the control range of a matrix converter with common mode free output voltage

Due to the function of conventional PWM inverters, additional bearing currents appear. As counter- measures, passive filter components and advanced control methods have been proposed [2]. Furthermore, some other configurations of the converter, like neutral point clamped inverter, are able to provide common mode free output voltages under some restrictions in the modulation scheme. Recently Mohan [8] proposed an arrangement of two matrix converters to feed an open winding arrangement of a three phase AC motor. This configuration combines the advantages of an increased output voltage with a common mode free output voltage supply. Unfortunately, the control range for the input reactive current is limited by some restrictions in the control scheme. The aim of this paper is to increase the control range of the input reactive current to the same value as reached with the conventional matrix converter in [9]. An appropriate control method will be presented here and will be proven by simulation.