全桥LLC谐振变换器稳定性分析与仿真研究

Stability Analysis and Simulation Research of Full-Bridge LLC Resonant Converter

针对目前全桥LLC谐振变换器传递函数难以得到及缺少可靠闭环稳定性分析方法进行研究,研究过程将控制回路融入变换器建模过程中,采用拓展描述函数法构造全桥LLC谐振变换器及控制回路的系统数学模型,并在此基础上引入Floquet理论判断全桥LLC谐振变换器系统闭环稳定性。另外,确定了控制参数对系统稳定性存在影响并给出了较为可靠的全桥LLC谐振变换器控制参数稳定范围。最后于Matlab中仿真验证理论正确性。此方法省略了变换器传递函数的求解过程,避免了高阶函数的计算,降低了稳定性分析的复杂程度;同时,此方法也适用于其它类型谐振变换器闭环稳定性分析。

In view of the difficulty in obtaining the transfer function of full bridge LLC resonant converter and the lack of reliable closed-loop stability analysis method,the research process integrated the control loop into the converter modeling process,useds the extended description function method to construct the system mathematical model of full bridge LLC resonant converter and control loop,and introduced Floquet theory to judge the closed-loop stability of full bridge LLC resonant converter system.In addition,it was determined that the control parameters have an impact on the stability of the system and a more reliable stable range of the control parameters of the full-bridge LLC resonant converter was given.Finally,the correctness of the theory was verified through simulation of Matlab.This method omits the process of solving the converter transfer function,avoids the calculation of higher-order functions,and reduces the complexity of stability analysis.At the same time,this method is also suitable for closed-loop stability analysis of other types of resonant converters.