PV Based Microgrid with Grid-Support Grid-Forming Inverter Control-(Simulation and Analysis)

Arangarajan Vinayagam,K S V Swarna,Alex Stojcevski,Aman Than Oo,Sui Yang Khoo

doi:10.4236/sgre.2017.81001

Abstract

Microgrid (MG) is a small entity of electrical network which comprises of various Distributed Generation (DG) sources, storage devices, and group of loads in various classes. MG provides reliable and secure energy supply to the critical loads of communities while operating either in on-grid or off-grid mode. In this study, a coordinated power management control strategy for a typical low voltage (LV) MG network with integration of solar Photovoltaic (PV) and storage facility has been developed and analysed in Matlab-Simu-link software environment at various modes (on-grid, off-grid, and on-grid to off-grid transition) of MG operation. Solar PV and battery power inverters are considered as grid-support grid-forming (GsGfm) Voltage Source Inverter (VSI) with the implementation of modified droop and virtual output impedance control strategies. Proposed control strategy supports coordinated control operation between PV units and battery storage, equal power sharing among the DG sources, and smooth MG mode transition with regulation of voltage and frequency level in MG network. In addition, voltage and current THD level were analysed and verified as per the standard of AS4777.

Highlights

IntroductionMG is a small entity of electrical network which comprises of multiple Distributed Generation (DG) sources, energy storage devices, and group of loads, which can be operated in either on-grid (grid connected) or off-grid (islanded) mode of operation [1] [2]
In on-grid mode, both PV units were allowed to operate in P-Q control mode and battery storage was allowed to charge and discharge according to availability of PV power generation with respect to power demand in MG network, solar irradiance level, and amount of power flow to the grid network
Voltage and frequency level in MG network, power sharing among PV units, battery storage, and grid source were analyzed with varying solar irradiance and load conditions

Summary

Introduction

MG is a small entity of electrical network which comprises of multiple DG sources, energy storage devices, and group of loads, which can be operated in either on-grid (grid connected) or off-grid (islanded) mode of operation [1] [2]. In either mode of MG operation, maintaining energy balance is necessary to get the better regulation of voltage and frequency level in MG network. In off-grid mode, all the DG sources should be responsible for ensuring power balance and regulation of voltage and frequency level in MG network through active coordinated power management and power sharing control strategies [3]. Due to the intermittent nature of PV power, a battery storage can be used to smooth out PV power variation and maintain the power balance in PV based MG network [4] [5] [6]

Results

Discussion

Conclusion