变频器输出滤波器的灵敏度分析与优化设计

Sensitivity analysis and optimal design for inverter output filters

现代变频器传动系统日益表现出各种负面效应,采用滤波技术是减小负面效应的主要对策.为综合满足滤波器的各种约束条件,并使滤波器整体性能达到最佳,研究了变频器输出滤波器的优化设计问题.首先建立了考虑成本因数、总谐波失真度、谐波电流和基波压降的综合目标函数.然后根据基波压降、电容支路电流工程允许范围,建立了滤波器元件参数的约束条件.为求得目标函数的最优解答,详细分析了目标函数对滤波器参数的灵敏度,并用伴随网络法得出了滤波器电压转移函数对滤波器参数灵敏度的解析表达式.这些灵敏度构成了目标函数的寻优方向.实例设计与仿真表明,利用优化方法设计的滤波器,能够综合考虑滤波器性能、成本和各种约束条件,从而实现整体指标最佳.

The optimal design of inverter output filter in AC motor drive system is investigated by combining the target functions including cost factor, total harmonic distortion ( THD) , harmonic current and voltage drop at fundamental frequency and establishing the constrains to filter components based on allowable range in engineering of harmonic current through capacitor and the voltage drop of inductor at fundamental frequency. To find the optimal solution of target function, the sensitivity of target function to the parameters of filter components are derived analytically, the accompanying network was employed to obtain the representation of the sensitivity of voltage transfer function to filter parameters. The searching directions in the optimization process are given by these sensitivities. The design examples and simulation results show that the proposed design and optimization method can taken into considerations performance, cost and other constrains of inverter output filter system to achieve the optimization of the whole system.