Modelling and Simulation of Compound PV-BESS Systems

The thesis reports on the modeling and simulation of PV systems with grid-connection. The research carried out assesses the impact of key parameters of Photovoltaic systems on power generation and power quality. It also examines a utilization of Battery energy storage system (BESS) which serves the purpose to support the active power production by charging and discharging the surplus and reduced power generation from PV. The use of renewable energy systems, such as Photovoltaic (PV), is becoming highly popular in modern power systems. However, the random and fluctuating nature of the solar resource increases the possibility of power mismatches between power generation and power demand in the grid. A large penetration of such a fluctuating energy resource can degrade the reliability of supply, the stability of system operation and introduce adverse power quality phenomena. Battery Energy Storage Systems (BESS) are recognized to be a viable solution to overcome the fluctuations present in PV systems. Hence, the integration of BESS with grid-connected PV systems will greatly enhance the reliability of the overall power grid. In this thesis, the modeling and simulation of PV-BESS is carried out using the MATLAB/Simulink environment. A test system comprising a 100 KW PV panel is connected through a DC-DC converter in tandem with a DC-AC inverter to a Point of Common Coupling (PCC) of an equivalent power grid. The effects of changes in solar irradiance and temperature, on the output power of the PV system, are assessed in the first part of the thesis. The integration of a BESS model in parallel with a PV system model is carried out in the second part of the thesis, where the overall intermittent behavior of the combined system is assessed. It should be stressed that the key purpose of integrating a BESS and a PV system is to provide constant power supply to the load system under varying environmental conditions. The outcome of this investigation shows that the integration of the BESS into the PV system yields very encouraging results in counteracting the fluctuation of the PV installation, helping to ensure a constant power supply to the load