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

This paper proposes the modified SVPWM control algorithm for the three-phase voltage source inverter, which consists of traditional six switches voltage source inverter and three bidirectional switches for creating the ac decoupling circuit. This topology has the advantages such as the ability to reduce the overall power losses in inverter system and beside that, to decrease the leakage ground current from PV panel (in case of photovoltaic systems) which is based on the principle of decoupling when the zero space vectors occur. For avoiding shoot-through states between six traditional switches and three bidirectional switches, a delay time has been inserted into switching time. The delay time has been controlled more complex to guarantee THD of output voltage, it´s called three-step switching algorithm. In oder to demonstrate the feasibility of this algorithm, the operation of the inverter and the modified SVPWM method is simulated by using Matlab/Simulink software and implemented in the experimental prototype by using FPGA Virtex 5 (Xilinx).