电网电压畸变时谐波电流检测方法研究

电网电压畸变状态下锁相环难以提供准确相位信息,影响谐波电流检测的精度,低通滤波器的存在会影响谐波检测的实时性。针对这些问题提出了一种改进的谐波电流检测方法,用正弦幅值积分器替代锁相环,从畸变电压中提取基波正序电压在电压畸变时仍能精确检测出谐波电流并用固定周期内的积分模块代替低通滤波器,降低了检测的时延,通过MATLAB仿真证实了方法的正确性和有效性。

A Study on Harmonic Current Detection Methods in Case of Grid Voltage Distortion

In case of grid voltage distortion,the phase-locked loop can hardly provide accurate phase information,a problem which affects the precision of harmonic current detection.Existence of the low-pass filter will affect the real-time performance of harmonic detection.In such background,this paper puts forward an improved harmonic current detection method by which the phase-locked loop is replaced with a sinusoidal amplitude integrator,and fundamental positive sequence voltage is extracted from distorted voltage,so that harmonic current can be detected accurately even in case of voltage distortion.Furthermore,an integral module of a fixed period is used in place of the low-pass filter to reduce time delay of the test.Results of MATLAB simulation verify the correctness and validity of this approach.