True Three-Phase Bidirectional Switch Based Buck Ac Voltage Controller Topology

Two bi-directional switch based three-phase buck AC voltage controller is presented in this paper. The operational principle of the proposed three-phase regulator is a direct consequence of using two three-phase bi-directional switches in the buck converter topology. The converter works on per phase basis and therefore three phase output voltages remain same in case of load unbalance. The topology has reduced number of switches for a three-phase AC voltage control having output voltage regulation, input current shaping and power factor improvement capability. Reduced number of switches allows simple control circuit, less switching loss, reliable operation and low cost. Steady state analysis and simulation results of open and closed loop control of the proposed converter are presented in this paper. The voltage mode feedback control method used for controlling the regulator shows acceptable regulation of the converter output voltage. During sudden variation of load or input voltage the controller adjusts the duty cycle to recover to the desired output voltage.