基于小波分析的优化PWM逆变系统控制

主要研究了变频调速过程中电机谐波和发热的难点问题。为此提出了采用小波分析实现谐波电压和电流的在线反馈跟踪,以获得谐波分量最小的优化控制方式。通过优化组合PWM逆变控制技术,使逆变器在整个输出频率范围内,保持电机谐波和发热最小的最佳工作状态。这种依据小波变换原理对IPM逆变输出电压进行采样,用DSP芯片软件完成小波计算测试谐波,适时性强,分辩率高,基波幅值误差小(误差精度小于5%),因而成功地解决了变频调速过程中PWM控制的谐波和电机发热问题。经实验测试,电机发热减少了35%,节能效率高,技术新颖,实用性强,为最终消除谐波实现闭环的PWM在线控制提供了一种新的设计思想。

Optimized PWM Inversion Control System based on the Analysis of Wavelet

This thesis focuses on the difficulties of motor harmonics and heating in the frequency conversion timing process.In the paper,three obvious ideologies are used to cut down the motor harmonic and heating,they are the analysis of wavelet which can realize the feedback and track on line of harmonious voltage or current, the optimized control way with smallest harmonic component,and the inversion control technology of selected combination of PWM.The way,in which the harmonics are sampled from IPM inversion output voltage and mea-sured by DSP chip software has several advantages as follows:better timing,accurate re-solving power,and small error of fundamental wave which is less than 5%.Consequently,the harmonics during PWM control and motor heating in the frequency conversion timing process are solved successfully.The experiments demonstrate that the motor heating decreases by 35%.For the high efficiency,new technology and practicality,a new design opinion is put forward to avoid harmonics and to realize closed loop PWM control on line.