新能源汽车双向全桥LLC变换器的设计与研究

Design and Research of Bidirectional Full Bridge LLC Converter for New Energy Vehicles

本文针对双向全桥LLC变换器进行了设计与研究。首先,针对双向全桥LLC变换器的工作原理进行了介绍与分析。对现有LLC电路的拓扑结构进行了优化,并运用基尔霍夫定律得到直流增益传递函数。利用基波近似法对变换器正向与反向运行状态进行了数学建模,进而得到正向与反向工作模式下的直流增益曲线。其次,运用扩展描述函数法对双向全桥LLC变换器进行了数学建模。经推导得到了小信号动态补偿模型,基于模型得到了双向全桥LLC的开环传递函数。进而实现了电路的动态分析及控制环路设计。最后,基于PSIM软件搭建仿真实验平台,分别验证了硬件控制环路和数字控制环路的工作性能。

This paper designs and studies a bidirectional full-bridge LLC converter. Firstly, the working principle of the bidirectional full-bridge LLC converter is introduced and analyzed. Use Kirchhoff’s law to get the DC gain transfer function. The forward and reverse operation states of the converter are mathematically modeled by the fundamental wave approximation method, and then the DC gain curves in the forward and reverse operation modes are obtained. Secondly, the bidirectional full-bridge LLC converter is mathematically modeled by using the extended description function method. The small-signal dynamic compensation model is derived, and the open-loop transfer function of the bidirectional full-bridge LLC is obtained based on the model. Then the dynamic analysis of the circuit and the design of the control loop are realized. Finally, a simulation experiment platform is built based on PSIM software, and the working performance of the hardware control loop and the digital control loop are verified respectively.