Linear Kalman Filter-Based Grid Synchronization Technique: An Alternative Implementation

Abstract

Grid synchronization techniques play a significant role in integrating renewable energy sources to the electric power grid. In this context, estimating the phase and frequency of the grid voltage signal is an interesting problem. Out of various techniques available in the literature, Linear Kalman Filter (LKF) is one of the most popular one. In this paper, we propose an alternative implementation of the LKF for grid synchronization application. The proposed implementation uses a linear parametric model of the grid voltage signal including DC offset. It does not involve any quadrature signal generation, rather it works by estimating the phase angle. This helps to estimate the unknown grid frequency directly from the phase angle. This clearly differentiates the proposed alternative implementation with respect to the existing implementations. Performance improvement by the proposed technique is verified extensively through comparative numerical simulation and experimental studies. Comparative results demonstrate the suitability of the proposed technique with respect to other state-of-the-art techniques namely Second-Order Generalized Integrator Phase-Locked Loop (SOGI-PLL) and Enhanced Phase-Locked Loop (EPLL).

Digital filter‐based grid synchronization for autonomous microgrids

“…In general terms, the covariance matrix of the estimation error and Kalman gain are set out in the Kalman algorithm to minimize the error generated over the process of predicting the variables [26]. Thus, the equations which are associated with the updating of these matrices are expressed by • A priori covariance matrix update…”

“…In [25], a recursive WLS filter was exploited to generate a fast dynamic response; but, its stability attribute could be more enhanced. Under harmonic distortion and DC offset circumstances, the frequency locked loop (FLL) is utilized in conjunction with a linear Kalman filter to estimate frequency amplitude as well as voltage [26]. Even though the synchronization technique discussed above performs well, the method's high sensitivity to unbalanced condition is the method's key shortcoming, which affects system stability.…”

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

“…A. Girgis in 1981 [2][3][4]. It mainly applies to the following fields: fundamental and harmonic components detection of grid voltage/current [5][6][7][8][9][10], phase−locked loop synchronization [11][12][13][14][15], power quality detection and compensation equipment [16][17][18][19][20], power disturbance feature extraction and machine classification [21][22][23][24], and etc. In these applications, two conventional models, phase angle vector (PAV) model and orthogonal vector (OV) model, are mainly used.…”

Frequency-Locked Loop Based on Active Noise Cancellation Syncretized Two First-Order Low Pass Filters

“…Signal synchronization is a key factor in the control of power electronic devices, so the accurate detection of voltage signal frequency and phase in the grid synchronization is essential [1], such as the three-phase grid inverter [2], shunt active power filter [3], and island detection [4], etc. Phase locked loop (PLL) and frequency locked loop (FLL) have become the most common methods for grid synchronization due to their simplicity and reliability [5].…”

“…In [17], a Comb Filter based on MSOGIs is proposed to quickly and selectively eliminate harmonics while ensuring steady state accuracy, and it removes the complex harmonic decoupling network and reduces the amount of calculation compared with MSOGI-FLL. However, the performance of these SOGI-based FLLs degrades in the presence of noise [1].…”