Power Management System Using Modified Control Strategy in Hybrid Renewable Generation System Connected to Grid

Abstract

The power management system using modified control strategy in a hybrid renewable generation system (HRGS) connected to grid is discussed. As the generation using photovoltaic (PV) cell is not steady everyday due to the change of irradiation level of the sun. So, PV system alone can’t fulfil the load demand throughout the day. Hence, a storage system is necessary for continuous power supply which can fulfil the load demand of the micro grid. The storage system consists of battery storage unit (BSU) and solid oxide fuel cell (SOFC). The BSU is used for the continuous power supply to the loads with PV module, weather PV power is available or not. If the state of charge (SOC) of BSU is less than 30%, then SOFC operates and fulfil the load demand. In this condition, less-priority load (????????) is disconnected and more-priority load (????????) is supplied continuously. SOFC also used to charge the BSU, when PV power is unavailable or it can be used to full fill the load demand. Hydrogen (????????) is used as a fuel input of SOFC for the power generation and this ???????? is produced by the electrolyser. By extracting the power of PV system, electrolyser splits the water (????????????) into ???????? and oxygen. This generated ???????? is stored in a ???????? tank (Storage Tank). Whenever, SOFC needs for the power generation, storage tank provides ???????? to the SOFC. In this paper, a modified control strategy has been developed according to the load demand, and able to manage the continuous power supply to the grid. The modified Perturb and Observe (P&O) maximum power point tracker (MPPT) is used for accurate power tracking due to variable irradiation. Voltage source converter control (VSCC) is used for synchronisation of grid and HRGS voltages. The supervisory control strategy (SCS) is designed for the overall control of grid connected HRGS.