新型有源箝位ZVS单级PFC变换器

Active-clamping ZVS single-stage PFC converter

针对传统功率因数校正(PFC)变换器存在的开关管电压应力高、硬性开通等问题,提出一种新型单级PFC变换器,在传统Boost升压电路基础上,结合移相全桥及有源箝位技术,利用一级电路就可实现PFC以及DC/DC变换。通过在桥臂两端并联有源箝位电路并结合适当的控制策略,吸收了变压器漏感在电路换流过程中产生的电压尖峰,降低了桥臂开关管的电压应力;利用变压器漏感与开关管寄生电容之间的谐振,使桥臂开关管和箝位开关管均实现零电压开关。在分析变换器工作原理的基础上,得到开关管零电压开关实现条件。实验结果表明,该变换器能够实现近似单位功率因数,开关管电压应力小且实现了零电压开关。

As the power switches of traditional PFC （Power Factor Correction ） converter working in hard -switching mode has high voltage stress ,combined with the techniques of phase-shifted full-bridge and active -clamping,a PFC converter based on traditional Boost circuit is proposed,which realizes the power factor correction and DC/DC conversion by single stage circuit. By the active-clamping circuit parallel to the bridge and suitable control strategy,the voltage spike induced during the commutation by the leakage inductance of transformer can be greatly absorbed and the voltage stress of power switches is reduced. Both the bridge switch and clamping switch realize the ZVS（Zero-Vohage-Switching） by making use of the resonance between the leakage inductance of transformer and the parasitic capacitance of switch. The conditions of ZVS operation are obtained by analyzing the working principle of converter. Experimental results verify that the proposed converter realizes near unity power factor,low switch voltage stress and ZVS.