Research on Dynamic Modeling of KF Algorithm for Detecting Distorted AC Signal

Kalman filter (KF) is often based on two models, which are phase angle vector (PAV) model and orthogonal vector (OV) model, in the application of distorted grid AC signal detection. However, these two models lack rigorous and detailed derivation from the principle of dynamic modeling. This paper presents a phase angle vector dynamic (PAVD) model and an orthogonal vector dynamic (OVD) model, which are combined with Kalman filter for detecting distorted grid AC signal. They reveal that the state noise covariance of the dynamic model−based KF is related to the sampling cycle, and overcome the defect of more detecting error for conventional model−based KF. Experiment and evaluation results show that the proposed KF algorithms are reasonable and effective. Therefore, this paper contributes a guiding significance for the application of KF algorithm in harmonic detection.

Harmonic detection algorithm based on Nuttall double-window all-phase Fast Fourier Transform trispectral interpolation

In harmonic detection of power grid, spectrum leakage of traditional FFT algorithm affects the accuracy of detection results. In this paper, a Nuttall double-window all-phase FFT trispectral interpolation algorithm is proposed. The phase of the spectral line with the maximum amplitude at the sampling point is taken as the initial phase of the signal, and the position of the main harmonic line is determined by using the amplitudes of the three spectral lines near the harmonic peak frequency point. Simulation results show that this algorithm can reduce the error of harmonic parameter detection more effectively and reduce the influence of white noise.

Harmonic Detection for Shunt Active Power Filter Using ADALINE Neural Network

This paper presents an efficient harmonic detection for real-time generation of the reference current fed to a shunt active power filter using the ADALINE neural network. This proposed method is a single layer with 101 nodes generating the coefficients referred to as weights of the reference current model. It effectively overcomes the drawback of the current technology, which is instantaneous power theory (PQ). The proposed method was implemented on the TMS320F28335 DSP board and tested against MATLAB with Simulink as a hardware-in-loop (HIL) structure. This method gives a good performance by producing a precise reference current in a short period with uncomplicated calculation. It also efficiently can eliminate individual harmonic current. The achieved percentage of total harmonic distortion (%THD) in the current is reduced following the IEEE standard, while the power factor can be maintained to unity.