Single-Phase Rectifier With Reduced Common-Mode Current, Auto-PFC, and Power Decoupling Ability

Abstract

Transformer and electrolytic capacitors (Ecaps) in light-emitting diode (LED) drivers lead to increased cost and shortened lifespan. Therefore, eliminating the transformer and Ecaps of the LED driver can not only achieve a lightweight design but also extend the service life. In this article, a novel single-phase transformerless capacitorless power factor correction rectifier is proposed. The proposed topology shares a common ground with the grid and the load. Thus, the reduced common-mode current is obtained, and the demand for an isolation transformer is eliminated. In addition, this article presents a unidirectional active buffer circuit to isolate the pulsating power, and the capacitor of the buffer circuit is multiplexed as an output filter. Compared with similar works, a lower voltage on the decoupling capacitor, fewer power components, and a simple control unit are obtained. Then, the operation principle and switching modes as well as the parameter design and implementation of the control strategy are elaborated systematically. Finally, an 80-W experimental prototype is built, and the experimental results confirm the feasibility of the proposed rectifier by reaching the efficiency up to 97.1% and the power factor to 0.984 at a wide range of operating voltage.