Multilevel Pulse Train Control for Three-Phase Voltage Source Inverter in dq Rotating Coordinate System

A novel multilevel pulse train (MPT) control scheme is proposed for stand-alone three-phase voltage source inverter (3ph-VSI). As the proposed control technique utilizes multilevel discrete duty cycles to approximate the desired duty cycles in dq rotating coordinate system, the output voltages of 3ph-VSI in dq system can be regulated. In addition, as the control parameters of the proposed control scheme are decided by rotating dq-axis output current referenced MPT method, the steady-state performance of MPT-controlled 3ph-VSI can be maintained over a universal output power range. The operation principle and implementation of the proposed control technique is analysed. Simulation results and experimental results are provided to show the effectiveness of the proposed MPT-controlled 3ph-VSI system with six-step PWM modulation.