The modified space vector PWM for three-phase voltage source inverter with AC decoupling circuit

Abstract

This paper proposes the modified space vector pulse width modulation (SVPWM) control algorithm for the three-phase voltage source inverter (VSI), which consists of traditional six switches VSI and three bidirectional switches for creating the ac decoupling circuit. This topology has some advantages such as the ability to reduce the leakage ground current from PV panel and therefore improve the efficiency of photovoltaic (PV) energy conversion based on the principle of decoupling when the zero space vectors occur. Likewise, no current flows through six traditional switches in zero space vectors, thus they operate at lower average temperature. In this case, the conduction losses are reduced. For avoiding shoot-through states between six traditional switches and three bidirectional switches, a delay time has been added to switching time and managed carefully to guarantee THD of output voltage. Operating of the inverter with the modified SVPWM method is simulated by using Matlab/Simulink software and implemented in the experimental prototype by using FPGA Virtex 5 (Xilinx).