Adaptive Harmonic Detection Method with Variable Step Size Based on l2 Norm and True Tracking Error

Abstract

The invention is based on the L2 norm and the true tracking error variable step size self-adaptive harmonic detection method, and the method is improved in the existing harmonic detection algorithm of the self-adaptive noise cancellation principle. First, the sliding integrator is used to find the feedback amount that can truly reflect the tracking situation, and then the updated feedback error is brought into the step size iteration formula to adjust the step size. The L2 norm is used to introduce the step size iteration formula to establish the error signal, which can reflect the impact of the input signal on the performance. This method is simple in calculation, accurate in tracking and detection signals, and strong in robustness. It can also maintain a fast convergence speed while ensuring a small steady-state imbalance, and it can also track the change of the load current well when the load current changes suddenly. , for both single-phase and three-phase systems.

Description

technical field [0001] The invention belongs to the technical field of harmonic current detection in electric power systems, and in particular relates to a variable step size self-adaptive harmonic detection method based on L2 norm and true tracking error. Background technique [0002] The large-scale use of nonlinear loads such as power electronic equipment has made the harmonic pollution of the power grid more and more serious. The access of large-scale new energy has further aggravated this situation and seriously affected the economic, stable and safe operation of the power system. Therefore, effective governance of harmonic pollution Waves are especially important. The active power filter (APF) can quickly and dynamically track and compensate harmonics and reactive power. It consists of a harmonic detection part, a current tracking part, a drive circuit and a main circuit part. As the primary link of harmonic control, harmonic detection plays a vital role in the qualit...

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Problems solved by technology

Document 1 "Application of Variable Step Size Adaptive Algorithm in Active Filter Harmonic Detection" (Li Hui, Wu Zhengguo, Zou Yunping, Liu Fei, Wu Yanfeng, Chinese Journal of Electrical Engineering [J].2006(09):99-10 3), this method uses the proportion K(n) of the error signal e(n) in the signal to be detected as the adaptive feedback amount, and adjusts the step size of the algorithm through the coherent average estimation of K(n), but when the current Near the zero crossing point, the algorithm will have difficulty in numerical calculation, and the ability to track sudden load changes is poor, and it cannot eliminate the interference of the fundamental reactive current on the step size update; Document 2 "A new fast adaptive harmonic detection algorithm "(He Na, Huang Lina, Wu Jian, Chinese Journal of Electrical Engineering [J]. 2008, (22): 124-129) This method proposes a fuzzy variable step size adaptive detection algorithm, but the self-adjustment factor introduced is a Vector, too many parameters, affecting the convergence speed

[0004] To sum up, the existing variable step size adaptive harmonic detection method is not capable of tracking current changes when the load changes suddenly, the calculation is too complicated, and the accuracy, convergence speed and steady-state accuracy of the detection results need to be improved.

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