用于车载充电机的谐振变换器及其控制策略研究

对于车载充电机应用，传统频率控制的LLC谐振变换器难以实现宽电压范围，也不利于车载充电机的优化设计。为了解决这些问题，基于一种具有混合整流器的谐振变换器，对其控制策略进行研究以实现宽输出电压。在这种结构中，转换器的副边侧整流二极管与输出滤波电容间的两个辅助开关管反接串联，将整流电路构成全桥-半桥的混合整流器。然后，提出了一种窄频率范围的频率控制和一种定频PWM控制，使得谐振变换器可以实现宽电压范围。与传统频率控制的谐振变换器相比，该转换器有如下优点：宽电压范围、低环流损耗、缩小了频率调节范围。最后，MATLAB/Simulink仿真和实验结果验证了该转换器和控制策略的有效性、可行性。

Research on Resonant Converter for On-board Chargers and Its Control Strategy

For on-board charger applications, the conventional frequency-controlled LLC resonant converter is difficult to achieve a wide voltage range, and it is also not conducive to the optimal design of on-board chargers. To solve these problems, based on a resonant converter with a hybrid rectifier, some control strategies are proposed to achieve the wide output voltage. In this topology, two auxiliary switches between the secondary-side rectifier diode of the converter and the output filter capacitor are reversely connected in series to form a full-half bridge hybrid rectifier. Then, a frequency control with a narrow frequency range and a fixed-frequency PWM control are proposed, so that the resonant converter can achieve the wide voltage range. Compared with the conventional frequency-controlled resonant converter, the proposed converter has advantages such as a wide voltage range, a low circulating loss and a narrowed frequency range. Finally, the effectiveness and feasibility of the converter and its control strategy were verified by MATLAB/Simulink simulations and experimental results.