基于频域法的DC/DC变换器传递函数设计方法研究

Research on Design Method for Transfer Function of DC/DC Converter System Based on Frequency Domain Method

目前常用解析法建立DC/DC变换器的小信号模型,频域法来验证其准确性,现采用一种新的思想是:直接利用频域法进行变换器的小信号建模。设计流程包括:分析频域法的原理和建模机制,介绍运用Matlab建模的实现流程,以典型移相全桥变换器为设计对象,利用Simulink搭建仿真模型,分别基于频域法和状态空间平均法(解析法)得到传递函数,采用PID Tuner设计控制参数,对比2种方法的波特图和输出电压。结果表明:频域法建模的波特图更精确,输出电压动态性能更好。

The small-signal model of a DC/DC converter is usually built by the analytic method,and its accuracy is verified by the frequency domain method.A new idea is developed to model the small signal of the converter,i.e.,directly using the frequency domain method.The design process is as follows:The principle and modeling mechanism of the frequency domain method are analyzed,and the realization flow of Matlab modeling is introduced.A typical phase-shifted full-bridge converter is taken as the design object,and a simulation model is built by Simulink.The transfer function is obtained on the basis of the frequency domain method and state-space averaging method(analytic method)separately,and PID Tuner is employed to design the control parameters.The Bode plot and output voltage of the two methods are compared.The results show that the Bode plotmodeled by the frequency domain method is more accurate,and the dynamic performance of its output voltage is better.