A STUDY ON THE COMPARISON OF TWO HARMONIC CURRENT DETECTING METHODS

There are so many harmonic current detecting methods that it is necessary to compare various methods in order to take full advantage of the characteristics of each method. This paper introduces two harmonic current detecting methods, an instantaneous harmonic current detecting method based on the phase distinguishing technology and an adaptive detecting method based on the adaptive interference canceling theory. Through numerical simulation and theoretical analyses, their characteristics are analyzed and compared in both time and frequency domains.A satisfactory detecting precision of the adaptive detecting method can be achieved by setting the integral gain K to the appropriate value. However, the higher detecting precision often conflicts with the faster dynamic response.A better tradeoff between the harmonic current detecting precision and the dynamic response of the instantaneous detecting method can be achieved by carefully choosing the type, order and the parameter of the low pass filter.