一种Buck变换器大信号非线性模型

多变换器系统广泛应用于航天航空、舰船电源以及新能源发电中。随着应用条件的变化,多变换器系统的工作点大幅改变,其大信号稳定性是系统分析与设计的关键。由于电力电子变换器的复杂性,多变换器系统大信号详细建模往往面临阶数过高、工作模式过多等问题。首先以平均电流控制的Buck变换器为例,分析了变换器不同工作模式的特征;然后,基于变换器平均模型给出一种大信号非线性模型,该大信号模型在DCM和CCM模式下具有统一的数学表达,并实现了系统的降阶;最后,通过逐周期仿真,验证了该模型的准确性。

A Nonlinear Large Signal Model of Buck Converter

Multi-converter systems have been widely used in many applications, such as aircraft, power system on ship, and renewable energy. With the variation of application conditions, the operation point of multi-converter system changes dramatically. The large signal stability is a key factor for analysis and design of systems. Due to the complexity of power electronic converters, the large signal modeling of multi-converter system often face high orders or multi-operation mode problems. In this paper, a Buck converter with averaged current mode control is taken as an example, the characteristics of converter under different operation modes is analyzed. Then, based on averaged model of converter, a nonlinear large signal model is proposed. This model has a unified mathematical expression under continuous and discontinuous conduction modes, and reduced orders. Finally, the accuracy of proposed model is verified by cycle-by-cycle simulation results.