一种高频高效的四开关Buck-Boost变换器控制策略

High frequency and high efficiency control of four switch Buck-Boost converter

针对四开关Buck-Boost变换器在整个输入电压范围内很难实现高效率、高功率密度和良好的动态响应等问题,对四开关Buck-Boost变换器传统控制策略进行了归纳。对传统控制策略存在的多模式切换、控制设计难度大、实现软开关复杂程度高等问题,提出了一种四开关Buck-Boost变换器混合单模式ZVS恒频控制策略,并对该变换器各个关键参数进行了优化设计,搭建了一台300 W实验样机并进行了测试。实验结果表明:四开关Buck-Boost变换器在该控制策略下不管升压还是降压电路都只工作在一种模式,并能在全电压范围内都能实现4个开关管的零电压ZVS开通,在高频工作时开关损耗低、效率高、动态性能好。

Aiming at the problems that the four-switch Buck-Boost converter is difficult to realize high efficiency,high power density and good dynamic response in the whole input voltage range,the traditional control strategy of the four-switch Buck-Boost converter was summarized. There are so many problems of the traditional control strategy,such as multi-mode switching,complex control to achieve soft-switching.A control strategy called'mixed one mode ZVS constant-frequency'of the four-switch Buck-Boost converter was proposed,a 300 W prototype was built up for testing. The experimental results show that in the control strategy the four-switch Buck-Boost converter work on only one mode and can achieve zero-voltage switching of the four switches in the full input voltage,the full output voltage and the full load range.