Abstract:Aiming at the problem between convergence speed and steady-state accuracy of traditional fixed step size LMS algorithm for harmonic detection, a improved variable step size LMS harmonic detection algorithms with higher convergence speed is presented.This algorithm used autocorrelation estimate of the error signal e(n), e(n-1) in the same phase in two adjacent time to adjust step size, and used normalization method , the k(n) and k(n-1) are as new feedback, which k(n) and k(n-1) are the proportion of the error signal in the total current signal, then using coherence average estimate of the feedback amount to control the step size updating; by introducing the disturbance of the absolute estimation error to update the tapping vector of the self-adaptive filter in weight iteration formula. Finally, MATLAB/Simulink simulation and experimental results show that the method compared to conventional fixed step size LMS harmonic detection algorithm has good performance on the convergence speed and steady-state accuracy, especially the method has good tracking performance in load mutation.
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