A single-phase rectifier with a neutral leg to reduce DC-bus voltage ripples

The voltage ripples of the half-bridge rectifier lead to the requirement on bulky electrolytic capacitors and voltage difference on the split capacitors. In this paper, a topology for a single-phase rectifier is proposed to reduce the DC-bus voltage ripples and voltage difference without using electrolytic capacitors. The proposed rectifier contains two legs: 1) A rectification leg to maintain the DC-bus voltage and to draw a clean input current with unity power factor; 2) A neutral leg to reduce DC-bus voltage ripples and the voltage difference. The two legs are independently controlled and the resulted high performance of the system is achieved. In order to test the system, real-time simulations were conducted and associated results are presented to demonstrate that the system is able to considerably reduce the DC-bus voltage ripples. With the derived system, the total required DC-bus capacitors can be reduced a lot when achieving the same level of voltage ripples.