Stability improvement and control of grid-connected photovoltaic system during faults using supercapacitor

Abstract

This paper describes the stability improvement of grid-connected photovoltaic (PV) system using supercapacitor (SC). The proposed technique is applied on PV system which using maximum power point tracking of perturbation and observation (P&O) algorithm. The P&O algorithm is used to extract the maximum power from the studied PV system. The effect of SC as a type of storage device on PV system appears at the abnormal conditions of grid faults. This technique is used to compensate the system parameters at different fault conditions. The control strategy of SC technique is developed for continuously charging and discharging to achieve its objective. In addition, the control system is presented in order to maintain the DC link voltage and to manage the power transit between the SC and the grid. The whole grid-connected PV system with SC energy storage system (ESS) is modeled and simulated using MATLAB/SIMULINK software and also the control system strategies are demonstrated. The effects of different fault conditions on the behaviors of studied grid-connected PV system with the SC ESS technique are investigated. A comparison between the behaviors of studied PV system in cases of without SC and with SC technique is studied. Also, the variations of DC voltage, active power, and reactive power for the studied PV system equipped without and with SC technique are investigated. The simulation results present a clear improvement for the system stability in case of using SC. Numerical results illustrate the validity of proposed technique with satisfactory values.