Control of a grid connected variable speed wind energy conversion system

Abstract

This paper presents a simple control strategy for a variable speed wind energy conversion system with a permanent magnet synchronous generator (PMSG). PMSG is connected to the grid through a switch mode rectifier and a voltage source inverter. The grid should be supplied by certain levels of powers for certain times from wind energy system according to a certain schedule. Batteries bank is connected to the DC-link voltage through a DC-DC bidirectional converter to maintain the DC voltage at constant value. Also it is used to make batteries bank stores a surplus of wind energy and supplies this energy to the grid during the wind power shortage. Voltage source inverter, at the grid side, uses a relatively complex vector control scheme to supply power at unity power factor into the grid. Simulation results have been performed using MATLAB/SIMULINK. It demonstrates that the controller performs very well in spite of variation in wind speed and demanded grid power. Also, maximum power extraction from wind turbine can be achieved through the switch mode rectifier control at the generator side.