A bridgeless hybrid-resonant PWM zero voltage switching boost AC-DC power factor corrected converter

This paper presents a new bridgeless zero-voltage switching (ZVS) ac-dc boost power factor corrected converter for application in power supplies and battery chargers. This converter utilizes standard average-current-mode control while operating in both pulse-width-modulation (PWM) mode and resonant mode each switching cycle. This modulation technique can be referred to as hybrid-resonant PWM (HRPWM). The PWM switches of the proposed converter can be driven with the same PWM signal, so extra circuitry is not required to sense the positive or negative line-cycle operation. The proposed converter realizes ZVS for the main and auxiliary switches which nearly eliminates all switching losses and enables improved efficiency. The resonant operation provides controlled di/dt turn-off of the output diodes which reduces the reverse recovery losses and electromagnetic interference (EMI). Detailed operation of the proposed converter is provided, along with a stress analysis of the circuit components, and a design methodology to select the resonant components. Finally experimental results are shown for a prototype unit converting a universal ac input to a 650W, 400 V dc output, operating at 70 kHz switching frequency.