Improved hardware implementation of a TSR based MPPT algorithm for a low cost connected wind turbine emulator under unbalanced wind speeds

Abstract

This paper presents the design, modeling, and the experimental build of a 1.5 kW relatively low-cost wind turbine emulator (WTE), based on the variable speed wind power system concept with partly rated power converters. The turbine simulator is composed of a controlled DC motor (DCM) in order to manage the static-dynamic behavior of a real wind turbine, including an ideal gearbox. This emulator is integrated into a connected wind energy conversion system chain (WECS), based on the double fed induction generator (DFIG) configuration. The latter ensures the electromechanical conversion. It allows the transfer of active and reactive power to the power grid during hypo and hyper synchronous modes. The aerodynamic emulation principle requires controlling the DC armature current with a PI controller. This leads to an electrical drive that applies a shaft torque identical to the wind turbine transmission drive train. The current reference is calculated as function of the static settings of the wind turbine and real wind speed data gives different operating points. In addition, this paper also proposes to test the TSR (Tip Speed Ratio) based MPPT algorithm to extract the maximum available power on the emulator by adjusting the rotational speed according to the actual given wind speed data. The MPPT, the DC motor control and the DFIG power control algorithms are implanted in C language, using dSPACE DS1104 control board, meanwhile simulations are done using MATLAB/Simulink. The experimental and simulation results show the effectiveness of using the controlled DC motor to emulate the wind turbine and also the great performances of the proposed MPPT structure to achieve the extraction of the maximum instantaneous power available on the drive shaft.