基于小波变换的充电机谐波检测方法研究

Research on Harmonic Detection Method of Charger Based on Wavelet Transform

电动汽车所采用的充电设备是一种高度非线性负载,其产生的谐波污染越来越严重,严重影响了电网的电能质量。论文分别采用快速傅里叶变换(FFT)和小波变换谐波检测方法对充电机进行谐波分析,从理论和仿真结果上说明小波变换优于快速傅里叶变换,更适用于充电机谐波检测,并基于此方法对充电机出现的噪声进行降噪处理和基波提取。通过MATLAB/Simulink搭建单台充电机等效模型,仿真结果表明,小波变换对一些非平稳、突变、暂态信号有很好的检测效果及可用性。

The charging device used in electrical vehicles is a kind of high non-linear load,and the harmonic pollution gener⁃ated by it is becoming more and more serious,which seriously affects the power quality of the power grid.In this paper,the fast Fou⁃rier transform(FFT)and wavelet transform harmonic detection methods are used to analyze the harmonics of the charger.From the theoretical and simulation results,the wavelet transform is better than the fast Fourier transform,which is more suitable for the de⁃tection of the charger harmonics.Based on the wavelet method,noise reduction processing and fundamental wave extraction are per⁃formed on the noise generated by the charger.The equivalent model of a single charger is built by MATLAB/Simulink.The simula⁃tion results show that the wavelet transform has good detection and usability for some non-stationary,abrupt and transient signals.