基于IPOS双LLC谐振变换器的恒压恒流充电研究

针对充电拓扑存在开关工作频率范围过宽的问题，提出了一种适用于蓄电池充电的IPOS双LLC谐振变换器，并针对其恒压恒流输出特性展开了研究。所提变换器包含两组LLC谐振腔，通过辅助开关管S的开闭改变其中一组谐振电容参数，从而实现变换器的恒压和恒流输出转换。恒压恒流模式下所提变换器均定频工作：在恒压模式(S闭合)，两组谐振腔工作在LC串联谐振点处；在恒流模式(S断开)，一组谐振腔工作在LLC谐振点处实现恒流输出而另一组仍恒压输出。所提变换器实现软开关的同时实现了原边开关管和副边整流二极管的复用，并详细介绍了其工作原理、电压电流增益、设计方法和控制方案。最后，通过实验和仿真验证了所提变换器的可行性。

Constant voltage and constant current charging based on an IPOS dual-LLC resonant converter

Current charging topology has the problem of a too wide switching frequency range. This paper proposes an IPOS dual LLC resonant converter suitable for battery charging, and conducts research on its constant voltage and constant current output characteristics. The proposed converter includes two sets of LLC resonant tanks. One set of resonant capacitor parameters is changed through the opening and closing of the auxiliary switch S, so as to realize the constant voltage and constant current output of the converter. In this mode, the converters all work at a fixed switching frequency: in the constant voltage mode (when S is closed), the two sets of resonant tanks work at the LC series resonance point; in the constant current mode (when S is off), one set of resonant tanks work at the LLC resonance point to achieve constant current output while the other group is still in the constant voltage mode. The proposed converter achieves soft switching while realizing the multiplexing of the primary side switches and the secondary side rectifier diodes. This paper introduces its working principle, voltage and current gain, design method and control scheme in detail. Finally, the feasibility of the proposed converter is verified through experiments and simulations. This work is supported by the National Natural Science Foundation of China (No. 61672337).