Variable-step adaptive harmonic detection method based on L2-norm and real tracking error
A tracking error and harmonic detection technology, applied in character and pattern recognition, signal pattern recognition, instruments, etc., can solve the problems of poor tracking ability of load mutation, many parameters, complicated calculation, etc., to achieve fast and accurate adjustment, avoid Delay effect, the effect of reducing a large number of calculations
Inactive Publication Date: 2018-07-10
HEBEI UNIV OF TECH
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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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[0078] In this embodiment, an adaptive harmonic detection method based on L2 norm and true tracking error, the steps are as follows:
[0079] (1) Sampling
[0080] For periodic non-sinusoidal load current i L (t) Sampling to obtain the discrete value i of the load current L (n), while making the grid voltage u S (t) Obtain the fundamental wave reference input unit vector x through the phase-locked loop (PLL) 1 (t) = sin(ωt), x 2 (t)=cos(ωt), and sample it to obtain the discrete value x of the fundamental reference input unit vector 1 (n)=sin(ωnT S ), x 2 (n)=cos(ωnT S ); Wherein, ω=2πf, f is frequency, f=50Hz, n is the discrete point of time t, T S is the sampling period;
[0081] (2) Input the fundamental wave reference into the discrete value x of the unit vector 1 (n), x 2 (n) input , get the output signal is the estimated value of the fundamental active current;
[0082] Among them, X(n)=[x 1 (n), x 2 (n)] T ;W(n) is the weight vector corresponding to X(...
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The invention discloses a variable-step adaptive harmonic detection method based on L2-norm and a real tracking error, and the method improves a conventional adaptive noise cancellation principle harmonic detection algorithm. The method comprises the steps: finding a feedback quantity which can truly reflect the tracking conditions through a sliding integrator, and then substituting an updated feedback error into a step iterative formula for step adjustment; introducing the step iterative formula to building an error signal through L2-norm, thereby reflecting the impact on the performances from an input signal. The method is simple in calculation, is accurate in tracking detection signal, is high in robustness, can maintain the quicker convergence while guaranteeing the smaller steady-state misadjustment, can achieve the tracking of the changes of a current when the current of a load changes abruptly, and is applicable to a single-phase system and a three-phase system.
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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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IPC IPC(8): G06K9/00G01R23/16
CPCG01R23/16G06F2218/04
Inventor 李志军王亚楠安平李笑张鸿鹏
Owner HEBEI UNIV OF TECH