飞机变频电力系统PWM整流器输出阻抗研究

Exploring Output Impedance of PWM Rectifier in an Aircraft's Variable Frequency Power System

PWM整流器是飞机变频电力系统中重要的功率变换设备,研究其输出阻抗特性与飞机变频电力系统直流环稳定性的关系具有重要意义。针对三相升压型PWM整流器,建立开环/闭环输出阻抗表达式,通过理论计算分析和仿真测试,研究了影响PWM整流器输出阻抗的参数,如供电电源频率、负载、输入电感、输出电容和控制带宽,由此得出改善整流器输出特性的方法。仿真结果表明,在控制带宽内,整流器输出阻抗主要决定于控制参数,在控制带宽外,输出阻抗主要决定于直流侧电容等无源器件,而供电电源频率和输入端电感对输出阻抗影响很小。根据阻抗特性的方法设计整流器的控制系统,有效优化整流器的性能和分析整流器带DC/DC变换器或电动机控制器等级联系统直流环的稳定性。

The PWM rectifier is an important power converter in an aircraft′s variable frequency power system , and it is necessary to explore the relationship between the output impedance of the PWM rectifier and the stability of the DC loop of the variable frequency power system .This paper establishes the mathematical model of a three-phase boost PWM rectifier and the open/closed loop output impedance expressions .With theoretical calculation and simu-lation, we analyze the various factors that affect the output impedance of the PWM rectifier , such as the frequency of power supply source , load, input inductance , output capacitor and control bandwidth , thus obtaining a method for enhancing the output characteristics of the PWM rectifier .The simulation results and their analysis show prelimi-narily that:(1) within the control bandwidth , the output impedance of the PWM characteristic is determined mainly by control parameters;(2) outside of the control bandwidth , it is determined mainly by source-free devices such as output capacitor , whereas the frequency of power supply source and input inductance affect little on the output im -pedance .The exploration results are useful for optimizing the PWM rectifier design and analyzing the stability of the DC loop of the rectifier with a DC/DC converter or the controller of a motor .