MFAC-PID control for variable-speed constant frequency wind turbine

Abstract

Due to the randomness and fluctuation characteristics of wind power, those model-based systems having intrinsically nonlinear are harder to be controlled. Based on the variable-speed constant frequency wind power generator, this paper presents a MFAC-PID control strategy to realize model-free, I/O data based dynamic control. Firstly, a control input criterion is established for optimal design, which realizes the targets of maximum wind energy capture and smoothing power point tracking. Then, by the usage of model free adaptive control (MFAC), a series of equivalent local linearization models are built using time-varying pseudo-partial derivative (PPD), which could be estimated only by I/O measurement data. Finally, considering that both MFAC and PID will generate incremental output, a constrained MFAC-PID algorithm is proposed in order to obtain the optimal input. The proposed strategy is verified with comparison to PID and MFAC methods. Results prove that MFAC-PID algorithm guarantees the convergence of tracking error at full wind speed.