A Fuzzy Logic Controller for IPMSG used in Wind Energy Conversion System

In this paper a fuzzy logic based approach is presented for control of small-scale Wind Energy Conversion System (WECS) over wide operating range. The considered WECS is equipped with fixed-pith blades and an Interior PM Synchronous Generator connected to a full-scale PWM rectifier. The proposed control strategy aims to track maximum power point at underrated wind speeds and harvest rated power of generator at overrated wind speeds. The space vector modulation-based direct torque control method is used to track the electrical torque and flux references. The reference of electrical torque is provided through a Fuzzy Logic Controller (FLC) achieving the maximum power point tracking. On the other hand, the reference flux magnitude is provided through a comprehensive strategy guarantying the machine operation over nominal rotational speed, limitation of the generated reference torque and copper-loss minimization. These are formulated as a nonlinear optimization problem which is solved numerically offline using the well-known sequential quadratic programming method. It should be noted that, the fuzzy rules are designed in such a way that not only result fast and accurate tracking performance at underrated wind speeds but also avoids irrational growth in reference electrical torque when the reference torque is limited by reference flux providing strategy. The proposed control strategy is verified by applying the strategy to a commercial 10 kW wind turbine simulated in MATLAB/Simulink.