Wind turbine emulator control improvement using nonlinear PI controller for wind energy conversion system: Design and real-time implementation

Abstract

Wind turbine emulators (WTE) have become a necessity for testing, developing, and improving design and control strategies in the renewable energy domain. The aim of this paper is to realize an experimental standalone wind energy conversion system emulator (WECSE) with improved torque and current control strategy using a nonlinear PI controller. The prototype was developed with a separately excited DC motor to simulate the wind turbine by providing the required speed and torque for power generation using a directly driven wound-rotor synchronous generator and a power conversion system controlled by a modified drift-free Perturb and Observe (P&O) Maximum Power Point Tracking algorithm (MPPT). The DC motor torque is controlled by an nonlinear PI controller regulator for an estimated current reference through a chopper driven by a dSPACE control board where the MATLAB/Simulink platform is used for wind turbine simulation. The proposed method was validated by experimental tests for different wind speeds and was compared with the conventional method. The experimental results have demonstrated that the control, emulation, and MPPT performances of the proposed method are significantly better.