低应力高效非对称半桥变换器设计

Design of low stress and high efficiency asymmetric half-bridge converter

非对称半桥变换器存在宽功率输出时效率不理想、电压电流应力大、整流二极管的电压振铃问题。针对这些问题,提出了一种低应力高效非对称半桥变换器,变压器次级引入带有正向电感L_f的倍压器结构来控制输出电流,有效地解决了整流二极管的电压振铃问题;L_f与倍压器中的电容构成精准谐振,实现开关管的零电压导通和整流二极管的零电流关断,最终实现高效宽功率输出;与其他非对称半桥相比,所提变换器的开关管和整流二极管具有低电压和电流应力。实验表明,所提变换器输出功率在10~100 W之间时,效率η_e在90%~96%之间;整流二极管电压无振铃;所提变换器的开关管S_1、S_2电压和电流应力较低,D_1、D_2电流应力也较低,但由于所提变换器变压器的次级不对称设计(n_1<n_2),D_2电压应力略高。

Asymmetrical half bridge converter has problems that wide power output efficiency is not ideal, the voltage and current stress is large, and rectifier diode has voltage ringing problem. So a low stress and high efficiency asymmetric half-bridge converter is proposed. A forward inductance Lfmultiplier structure is introducal transformer secondary to solve the rectifier diode voltage ring-ing problem. Lfresonates with the capacitors in the voltage double achieves a zero-voltage turn-on of switches and a zero-current turn-off of diodes, and achieve, high efficiency and wide power output. Compared with other asymmetric half-bridge, the proposed converter switch and rectifier diodes have low voltage and current stress. Experiments show that when the proposed converter output power is between 10 - 100 W, the efficiency ηeis between 90 % - 96 %, rectifier diode voltage is without ringing, proposed converter switch S1, S2 voltage and current stress is low, D1, D2 current stress is also low, but because of the proposed converter transformer secondary asymmetric design（n1〈n2）, D2 voltage stress is slightly higher.