Maximum Power Point Tracking of Wind Energy Conversion Systems Based on Sliding Mode Extremum Seeking Control

This paper presents a novel maximum power point tracking (MPPT) control method for variable-speed constant-frequency wind energy conversion systems (WECS). The proposed tracking method combines the ideas of sliding mode (SM) control and extremum seeking control (ESC). The only input needed in this method is the output active power of the generator. It avoids some difficult problems in traditional tracking algorithms, such as measuring the wind velocity, needing wind-turbine model and parameters, and detecting the gradient of power vs. rotor speed. The proposed method is tested on a double fed induction generator based wind energy conversion system. The back-to-back converters connected to the generator adopt the vector control method. The simulation model of an example WECS is established in MATLAB. The reference input of speed loop in the vector control is the optimal result resulting from the MPPT based on sliding mode ESC. Simulation results confirm the validity of this method.