A Full-Bridge Converter with Asymmetric Duty Cycle Control for Low Common Mode Noise

Abstract

In this paper, a new full-bridge (FB) converter with asymmetric duty cycle control for low common mode (CM) noise is proposed in order to achieve high power density. The conventional phase shifted full-bridge converter (PSFB) has a large CM noise, which increases the volume of the CM choke. The proposed converter uses a coupled inductor and an asymmetric duty cycle control to generate the similar voltage variations of the transformer at the primary and secondary side. A CM noise generated from the transformer can be reduced because dv/dt characteristic of the primary side is similar to it of the secondary side. As a result, the proposed converter can achieve high power density by reducing the volume of the CM choke. The performance of the proposed converter is verified by the experimental results with a 56 V/13.4 A 750 W prototype converter.