MPPT of VSCF wind energy conversion system using extremum control strategy

This paper presents the energy conversion optimization control strategy for a horizontal axis variable speed fixed pitch wind energy conversion system, which works in the partial load region. The system uses a variable speed wind turbine (VSWT), driving a squirrel-cage induction generator (SCIG) connected to a grid. Reference to the wind turbine model and its parameters are poorly known, so a new Maximum Power Point Tracking (MPPT) method is proposed based on the extremum seeking control principles. The aim is to drive the average position of the operating point near optimality. Here, the wind turbulence is used as search disturbance instead of inducing new sinusoidal search signals. The Fast Fourier Transform (FFT) processing of some available measures estimate the operating point's distance to optimality. The effectiveness of the proposed MPPT scheme is validated under different operating conditions by numerical simulations. The simulation results prove that this new approach has effectively suppressed the system vibration and enhanced system dynamic performance.