Commutation Strategy of Reconfigurable Grid-Connected Inverter to Improve Power Quality

A reconfigurable grid-connected inverter, called shunt-series-switched multi-functional grid-connected inverter (SSS-MFGCI), can be connected to the grid in shunt or series according to the different power quality problems and grid conditions. It is a key technology of SSS-MFGCI to make a smooth transition from shunt to series or vice versa by commutating bidirectional switches. These bidirectional switches operating in four-quadrant should be conducting in both current polarities and blocking both voltage polarities. Therefore, this paper proposes a proper commutation method of bidirectional switches of SSS-MFGCI. Switch realization and commutation strategies of bidirectional switches are presented. Simulated results are presented using MATLAB/Simulink to prove the concept of a proposed commutation strategy.