scholarly journals Optimal reactive power support for distributed Micro Grid through PV-Grid connected inverter

Author(s):  
G. Vijai ◽  
P. Selvam

The need for energy is increasing day-by-day, which is a large part of total global energy consumption. The crises of fossil fuels and nuclear power will run out someday in the future. Therefore, we aim to develop energy from Renewable Energy Sources (RES) especially from solar. The growth of solar energy has increase day by day to meet the demand in the future. In this paper, modeling and analyzing of a transformer-less grid-connected inverter is proposed for solar photovoltaic (PV)-grid interface system. The scope of the transformer-less inverter is used to minimize ground leakage current in the grid. The inverter is directly connected to unbiased grid line and PV array inverting terminal to compensate the ground leakage current. The transformer-less grid connected inverter is used to compensate reactive power, extraction of high energy from PV array, and low grid current distortion. The inverter is also used to improve tracking output current reference, grid synchronization, and to provide a safety margin of forced direct current into the grid. In the control circuit the Proportional Resonant (PR) controller is used. Atmega328 based reduced rated hardware is developed for verifying the system enhancements and the experimental results are used to prove the proposed methodology for control of transformer less grid interactive inverter which supports both active and reactive power to the loads.


2012 ◽  
Vol 466-467 ◽  
pp. 1079-1083
Author(s):  
Xiao Bin Mu ◽  
Jiu He Wang ◽  
Sheng Sheng Xu ◽  
Wen Gu

Photovoltaic (PV) grid-connected system requires the inverter possesses excellent dynamic and static characteristics. In the view of the mathematical model of the inverter is nonlinear, we will adopt a kind of nonlinear control strategy called Passivity–Based Control (PBC). First we establish the standard Euler – Lagrange (EL) mode for inverter, then we also prove that this inverter is strictly passive. Based on passivity of inverter, we can redistribute the system energy, and adopt the approaches of injecting damping and decoupling to improve system performance. In this paper, we can control the active and reactive power of system to make system can fast track the PV array maximum power point, and possess the capacity of compensating the reactive power. Simulation results show that passivity-based control method can make the inverter possess better robustness and dynamic.


Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2107 ◽  
Author(s):  
Min-Rong Chen ◽  
Huan Wang ◽  
Guo-Qiang Zeng ◽  
Yu-Xing Dai ◽  
Da-Qiang Bi

The optimal P-Q control issue of the active and reactive power for a microgrid in the grid-connected mode has attracted increasing interests recently. In this paper, an optimal active and reactive power control is developed for a three-phase grid-connected inverter in a microgrid by using an adaptive population-based extremal optimization algorithm (APEO). Firstly, the optimal P-Q control issue of grid-connected inverters in a microgrid is formulated as a constrained optimization problem, where six parameters of three decoupled PI controllers are real-coded as the decision variables, and the integral time absolute error (ITAE) between the output and referenced active power and the ITAE between the output and referenced reactive power are weighted as the objective function. Then, an effective and efficient APEO algorithm with an adaptive mutation operation is proposed for solving this constrained optimization problem. The simulation and experiments for a 3kW three-phase grid-connected inverter under both nominal and variable reference active power values have shown that the proposed APEO-based P-Q control method outperforms the traditional Z-N empirical method, the adaptive genetic algorithm-based, and particle swarm optimization-based P-Q control methods.


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