DC/DC变换器精确频响特性分析与测量

Accurate Frequency Response Characteristics Analysis and Measurement of DC/DC Converters

采用一种非平均模型法对DC/DC变换器的精确频响特性如输入阻抗、输入输出电压传递函数等进行了分析。由于电力电子变换器同时具有连续和离散时间系统特性,平均模型法和离散模型法均不能对其进行精确的动态特性分析。提出将DC/DC变换器的切换开关等效成一个时变电路,从而将整个系统看成一个线性时变系统,使系统同时具备精确性和易于分析性。在此基础上,对DC/DC变换器的频响特性进行了解析求解分析和实验测量。实验证明,该方法克服了平均模型法和离散模型法的频率范围限制,在开关频率附近及开关频率之上均能精确反映DC/DC变换器的动态特性。

A non-average method is used to analyze the accurate frequency response characteristics of DC/DC converters,including input impedance,voltage transfer function, etc.Both average model and sample data model can＇t be used to describe the accurate dynamical characteristics of DC/DC converters,which have continuous time system features and discrete time .system features.The DC/DC converters are modeled as linear time-variant systems,where the switches are seen as time-varying circuits.In this way,the analysis of frequency response characteristics become easier and more accurate,especiaUy without the limitation in the frequency range,which is a main obstacle in the average model and sample data model methods.The analysis and measurement of accurate frequency response are performed based on this model.