一种三通道三电平宽电压范围LLC谐振变换器

A THREE-POWER-CHANNEL THREE-LEVEL LLC RESONANT CONVERTER WITH WIDE VOLTAGE RANGE

为解决传统LLC谐振变换器在光储系统等宽电压范围应用中存在整体效率低和开关频率范围宽等问题,提出一种三通道三电平宽电压范围LLC谐振变换器。该变换器具有双通道和三通道两种工作模式,通过组合不同模式下的增益实现宽输出电压范围。变换器能在全电压范围内实现软开关,工作于固定开关频率,具有参数与磁性元件设计简单等优点。详细分析变换器各种工作模式的原理与增益特性,并明确变换器实现ZVS的条件。最终基于GaN开关器件设计并搭建一台输入电压200 V、输出电压5~20 V、最大功率200 W的实验样机,验证所提拓扑的可行性与理论分析的正确性。

Due to the wide switching frequency range and low overall efficiency,traditional LLC resonant converters are not suitable for wide voltage gain applications such as photovoltaic energy storage system,this paper proposes a three-channel three-level wide voltage range LLC resonant converter.The proposed converter operates in dual-channel or three-channel modes,achieving a wide voltage range by combining the gains in different modes.It enables soft switching over the full voltage range,operates at a constant switching frequency,and offers advantages such as simple parameter and magnetic component design.The article details the working principles,gain characteristics,and the conditions for achieving zero voltage switching(ZVS).Finally,A GaN-based 200 W prototype with 200 V input and 5-20 V output is designed and built to verify the feasibility of the proposed converter and the correctness of the theoretical analysis.