Novel adaptive harmonic detecting algorithm

The self-adaptive harmonic detection method, which is based on the principle of self-adaptive noise countervailing, is easy to be realized and has strong self-adaptive ability. But the fixed step-size will make a compromise between convergence speed and steady precision, which restrict its practicability. An improved variable step-size self-adaptive harmonic detection method is proposed in this paper. The proposed method adopts a sliding integrator and then uses a fuzzy adjustor with self-adjustable factor to modify the step size, so it can obtain fast convergence speed and high steady precision at the same time. Furthermore, the sliding integrator and fuzzy adjustor have simple configuration and are easy to be realized in DSP. Finally the three-phase and every order harmonic detection method are analyzed in order to widen its application range. The detailed simulation and experimental results verify the validity of this method.