High-Efficiency Asymmetrical Half-Bridge Converter with Series Capacitor Rectifier and Linear Voltage Gain

Asymmetrical half-bridge (AHB) converter is one of the widely used topologies in low to medium power applications such as industrial adapters and home appliances. In this paper, an AHB converter with series capacitor rectifier is proposed. The proposed converter has linear voltage gain and zero DC-offset current in the transformer through a symmetrical operation. Due to linear voltage gain, it has a narrow range of operating duty ratio. In addition, it has improved ZVS conditions of primary switches by zero DC-offset current in the transformer, which results in reduced switching loss. Moreover, a balanced average current flows through the diode, which reduces the conduction loss of the diode. As a result, the proposed converter has high efficiency under entire load conditions. Experiments were conducted with a 400 W prototype of 300-400 V input and 48 V output conditions.