Discrete Time Control Method for SVM Direct Active Power and Stator Flux Control of PMSG-Based Wind Turbine

Abstract

This paper proposes a new method for direct control of active power and stator flux of permanent magnet synchronous generator (PMSG) used in the wind power generation system. Active power and stator flux are controlled by the proposed discrete time algorithm. Despite the commonly used vector control methods, there is no need for inner current control loops. To decrease the errors between reference and measured values of active power and stator flux, the space vector modulation (SVM) is used, which results in a constant switching frequency. Compared to vector control, the proposed direct control method has advantages such as higher dynamic response due to elimination of inner current control loops and no need to coordinate system transformation blocks as well as the PI controllers and their adjustment. Moreover, permanent magnet flux vector and several machine parameters such as stator inductances are not required which can improve the robustness of the control system. The proposed method can be used in both types of surface-mounted and interior PMSGs. The effectiveness of the proposed method in comparison to the vector control method with optimized PI coefficients by the particle swarm algorithm is evaluated. Simulation results performed in MATLAB/Simulink software show that higher dynamic response with lower active power and the stator flux ripple are achieved with the proposed method.