(IJACSA) International Journal of Advanced Computer Science and Applications, Vol. 9, No. 8, 2018 239 | Page www.ijacsa.thesai.org Comparative Study of PMSG Controllers for Variable Wind Turbine Power Optimization Asma Hammami, Imen Saidi, Dhaou Soudani Automatic Research Laboratory, LA.R.A, National Engineering School of Tunis, ENIT University of Tunis El Manar Tunis, Tunisia Abstract—With a large increase in wind power generation, the direct driven Permanent Magnet Synchronous Generator is the most promising technology for variable speed operation and it also fulfills the grid requirements with high efficiency. This paper studies and compares conventional based on PI controller and proposed control technique for a direct driven PMSG wind turbine. The generator model is established in the Park synchronous rotating d-q reference frame. To achieve maximum power capture, the aeroturbine is controlled through Maximum Power Point Tracking (MPPT) while the PMSG control is treated through field orientation where the two currents control loops are regulated. A proposed direct-current based d-q vector control design is designed by the integration of the Internal Model Controller. Then an optimal control is developed for integrated control of PMSG power optimization and Voltage Source Converter control. The design system was done using SimWindFarm Matlab/Simulink toolbox to evaluate the performance of conventional and proposed technique control of PMSG wind turbine. The analysis, simulation results prove the effectiveness and robustness of the proposed control strategy. Keywords—Wind turbine; internal model control; PI controller Permanent Magnet Synchronous Generator (PMSG); vector control I. INTRODUCTION Recently, wind energy system has been treated as an important renewable energy source which had higher potential to generate power where grids are not feasible. The wind generation systems have gained tremendous attention over fossil fuel and nuclear power generation due to the high cost and environmental clean [1]. At present the variable speed wind turbine is considered the most attractive solution to distribute power generation systems. Mainly four types of generators are used in wind power system: Squirrel cage induction generator – double fed induction generator – wound rotor synchronous generator – permanent magnet synchronous generator (PMSG). Considerable research has been devoted to the choice of PMSG for variable speed generation system. It has high efficiency, is connected directly to the turbine without gearbox and has full controllability of the system for maximum wind power extraction [2]. However, the performance of PMSG depends on the control strategy. Traditionally, PMSG with full scale PWM converter is controlled through the conventional decoupled d-q vector control. The overall problem that occurs in this method is the calculation for determination of controller parameters and the robustness performance. Most studies have used the adaptive control scheme as a robust method of control strategy while others use the artificial intelligence techniques. These structures are required for exact mathematical identification of controller parameters. The Internal Model Control method was observed by Gracia and Morari [3], [4], and was later improved under intensive research and development. This design provides high performance dynamic characteristics. This structure covers an internal model of the plant and an internal model controller. In order to improve the disturbance rejection, a modified IMC is designed with an additional filter [5]. It provides good abilities of control system performance particularity for the stability and robustness issues. This paper proposes a comparative study between conventional vector control with PI action controller and proposed IMC controller design applied for the purpose of improving the control effectiveness and overall performance of PMSG system. This paper is structured as follows: In section 2 a mathematical model of the wind turbine with PMSG system is described. Section 3 deals with the PMSG control including the IMC proposed control is developed in section 4. The designed and traditional controls are compared and the validation results using SimWindFarm Matlab/Simulink toolbox are shown in section 5. II. WIND TURBINE MODELING A. Aeroturbine Modeling The aerodynamic blades allow the conversion of the kinetic energy of the wind profile into mechanical energy to the generator. Therefore the aerodynamic torque a T is given by [6]: 3 1 (, ) 2 a w p r T AV C      Where  is the air density, A is the surface, w V is the wind speed. Each wind turbine is defined by its own power coefficient which is a nonlinear function depends on the pitch angle  and the tip speed ratio  . The power coefficient can be represented as [6]: