Load Controller for a Stand Alone Variable Speed Wind Energy Conversion System with Energy Storage

This paper reports on a load controller for a standalone wind power plant with storage. The controller incorporates a maximum power point tracking (MPPT) algorithm for always capturing maximum energy from wind flow. The load is modelled as a three-phase resistor and is interfaced with the variable speed wind turbine and permanent magnet synchronous generator (PMSG) through a diode bridge rectifier, DC-DC converters, and a three-phase voltage source inverter. Maximum power point tracking is implemented by varying the duty cycle of a boost converter with the changes in the DC-link power and voltage. The energy storage system comprises a lead-acid battery bank that stores excess energy and supplies the load when wind generation cannot sufficiently meet the load demand. The three-phase voltage source inverter converts DC voltage to AC and employs vector control to sustain a constant output voltage across the load. Modeling and simulation are performed in MATLAB/Simulink for varying wind speeds and loading scenarios. The simulation results demonstrated that the controller performs well under these conditions.