Special Issue Article Open Access

Grid Synchronization by Estimation of Positive Sequence Component in Three Phase Signals

Abstract

Distributed Generation (DG) System is a small scale electric power generation which is based on wind energy, fuel cell, photo voltaic system, hydro etc. Grid Synchronization is one of the most important issues in the control of inverters connected to the grid. The proper operation of grid connected inverter system is determined by grid voltage conditions such as phase, amplitude and frequency. A discrete phase-locked loop (PLL) is used to track the phase angle in order to improve the synchronization systems response in adverse grid conditions. Using the enhanced synchronization structure the fundamental positive-sequence component of grid voltages in asymmetric and distorted three-phase systems is estimated. The α-β stationary frame is used to obtain the pulsation for grid inverter using a space vector pulse width modulation (SVPWM). The performance of the proposed structure is verified through simulations using a grid set of ideal and non-ideal grid conditions (three-phase voltage unbalance, variation in frequency, variation in amplitude and phase shift).The simulation results demonstrates that the proposed method is very effective in digital structure synchronization .

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