Load power management control for a stand alone wind energy system based on the state of charge of the battery

This paper presents a load power management control strategy for the operation of a stand-alone variable speed wind turbine with a permanent magnet synchronous generator (PMSG) based on the state of charge (SOC) of the battery. The PMSG is connected to a three phase load through a switch mode rectifier and a voltage source inverter. Battery storage system is connected to the DC-link voltage through a DC-DC bidirectional converter to maintain the DC-link voltage at constant value. Also, it is used to make the batteries bank stores a surplus of wind energy and supplies this energy to the load during a wind power shortage. The SOC changes during charges/discharges the batteries bank. The instantaneous change in the SOC and its value are used to connect/disconnect some loads to/from the consumers´ load. The voltage source inverter uses a relatively complex vector control scheme to control the output load voltage in terms of amplitude and frequency under variation of wind speed and load. Control of the generator side switch mode rectifier is used to extract maximum power from available wind power. Extensive simulations have been performed using MATLAB/SIMULINK. Simulation results demonstrate that the performance of the controller is quite satisfactory.