一种高频非理想DCM反激变换器建模与设计

Modeling and Design of a High Frequency Non-ideal Flyback Converter in DCM

针对反激变换器因高频特性描述不准确而误导补偿参数设计的问题,根据平均开关模型法,建立工作于断续导通模式(DCM)下非理想反激变换器小信号模型,并推导包含高频零极点的控制环路传递函数;分析控制环路幅频特性与相频特性,并搭建基于电流模式控制芯片KP2201的反激变换器SIMPLIS仿真模型,与实验样机进行测试验证。仿真与实验结果均表明,基于所提模型预测的控制环路能够有效描述系统工作特性,在频率响应及动态响应上均具有良好的一致性,为工程应用中设计稳定系统提供参考。

Aiming at the problem of misleading the design of compensation parameters caused by inaccurate description of the high-frequency characteristics of the flyback converter,the small-signal model of the nonideal flyback converter operating in discontinuous conduction mode(DCM)is established by using the average switching model method,and the control loop transfer function containing high-frequency zero-poles is derived.Then the amplitude-frequency characteristics and phase-frequency characteristics of the control loop are analyzed,and the SIMPLIS simulation model and experimental prototype of the flyback converter based on the current mode control chip KP2201 are built for testing and verification.The simulation and experimental results show that the control loop based on the model prediction can effectively describe the operating characteristics of the system,the experimental results have good consistency in frequency response and dynamic response,which can provide a reference for designing stable systems in engineering applications.