Buck变换器的变分积分离散时间建模  

Discrete-Time Modelingof Buck Converter by Means of Variational Integrator

作　　者：郑万里[1] 佃松宜[1] 

机构地区：[1]四川大学电气信息学院,四川成都610065

出　　处：《计算机仿真》2015年第1期287-291,共5页Computer Simulation

摘　　要：关于开关功率变换器设计问题,为了提高变换器性能,一般采用离散时间模型进行电路非线性动力学分析和数字控制器设计。现有的离散时间映射模型由于矩阵指数和积分的存在,运算量非常大,进行了大量近似,导致模型精确度的降低,无法反映出电感电流纹波等动态特性,直接影响了动力学分析的准确性和数字控制器的性能。提出采用变分积分原理对Buck变换器建立离散欧拉-拉格朗日方程,进而推导出运算量小且精度高的离散时间演化映射模型。仿真结果表明,所建立的模型能真实反映电感电流纹波等动态特性,电流和电压跟踪误差仅为近似离散迭代映射模型的5%,精确度显著提高。For power-switching converters, discrete-time model is primarily used for circuit nonlinear dynamics analysis and digital controller design. In existing discrete-time models adopt over-approximating methods are often used, which leads to less accurate, can not reflect inductor current ripple, and directly affects the accuracy of dynamic analysis and the performance of digital controller. Therefore, in the paper, discrete Euler-Lagrange equations of Buck converter were derived by means of variational integrator method and then the nonlinear discrete-time model was obtained with small amount of computation and high accuracy. Simulation results show that compared with existing discrete time model, the discrete evolution map model can reflect the inductor current ripple dynamically and current and voltage signals tracking error are only 5% of the error of existing model and the accuracy improved significantly.

关 键 词：开关功率变换器 变分积分器 欧拉-拉格朗日方程 离散时间建模 

分 类 号：N945.12[自然科学总论—系统科学]