基于状态平面分析法的LLC谐振变换器四阶段软启动

Four-Stage Soft Startup of LLC Resonant Converter Based on State Plane Analysis

LLC谐振变换器的启动过程是一个复杂的动态过程,现有的启动方案往往很难同时保证谐振电流在电流限值之下且启动过程迅速。为实现快速且稳定的软启动,该文提出基于状态平面分析法的LLC四阶段软启动方案。通过对LLC启动过程中状态轨迹的分析,将LLC的启动过程分为4个阶段,并对各个阶段的谐振电流进行计算,保证谐振电流的最大值不超过电流限值,根据各个阶段设计不同的实现方式,并介绍LLC四阶段软启动方案的数字控制实现方法。搭建仿真模型和实验样机,验证LLC四阶段软启动方案的安全性与快速性以及计算方法的精确性与合理性。

The startup process of LLC resonant converters is a complex dynamic process,and existing startup schemes often struggle to simultaneously ensure that the resonant current remains below the current limit and achieve a rapid startup.To achieve a fast and stable soft startup,this paper proposes a four-stage soft startup scheme for LLC based on state plane analysis.Through analyzing the state trajectory during the LLC startup process,the LLC startup process is divided into four stages.The resonant current at each stage is calculated to ensure that its maximum value does not exceed the current limit.Different implementation methods are designed for each stage,and the digital control implementation method of the LLC four-stage soft startup scheme is introduced.A simulation model and experimental prototype were built to verify the safety,speed,and the accuracy and rationality of the calculation of the four-stage soft startup scheme for LLC.