Single-phase half-bridge rectifiers with extended voltage ranges and reduced voltage ripples

For single-phase half-bridge rectifiers, the output voltage must be higher than twice the peak value of the supply voltage and bulky electrolytic capacitors are often needed to smooth the voltage ripples. In this paper, an improved half-bridge rectifier is proposed by adding a neutral leg to the conventional half-bridge rectifier and relocating the load. Benefiting from the added neutral leg, the voltage across the upper capacitor can be used as the output voltage. As a result, the range of the output voltage is extended and can be just higher than the peak value of the supply voltage. Moreover, the neutral leg is also used to transfer all the voltage ripples to the lower capacitor. Accordingly, the output voltage can be almost ripple free and the DC-bus capacitor can be reduced in order to achieve the same level of voltage ripples. The system power density can then be improved because of smaller capacitors. The proposed rectifier is tested on a real-time digital simulator and the obtained results are presented for validation.