双沿调制的四开关Buck-Boost变换器

Dual Edge Modulated Four-switch Buck-Boost Converter

与传统的Buck—Boost变换器相比，四开关Buck—Boost变换器具有输入输出同极性、开关管电压应力低等优点。该文针对四开关Buck—Boost变换器在通信电源分布式系统中的应用，提出三模式双频双沿调制的控制策略。该控制策略将变换器分成Buck单元和Boost单元，此两单元分别采用后沿调制和前沿调制，并且在Buck—Boost工作模式时，开关频率由Buck以及Boost模式的200kHz降到40kHz，以提高变换器的效率。实验室制作了一台48V（33-75V）输入48V／6．25A的样机，对所提出的控制策略进行验证。试验结果表明所得结论正确。

Compared with the traditional Buck-Boost, four-switch Buck-Boost converter has some advantages, such as ground sharing between input and output, low voltage stress of the switches. A three-mode double-frequency dual-edge modulation control strategy was proposed for the distributed power supply applied in communication system. In this control scheme the four-switch Buck-Boost converter is divided into two parts, the Buck parts and the Boost parts. In Buck or Boost mode only one part is selected to regulate the output voltage. In the Buck-Boost mode, the switching frequency is reduced from 200kHz to 40kHz to reduce the switching power loss. With the proposed control scheme, the four-switch Buck-Boost （FSBB） converter can achieve high efficiency. A 48 V （36-75 V） input, 48 V/6.25 A output prototype was built in the laboratory. The experimental results show that the conclusions are correct.