Sensor-less field oriented control of wind turbine driven permanent magnet synchronous generator using flux linkage and back EMF estimation methods

Abstract

The study aims at the speed control of the wind turbine driven Permanent Magnet Synchronous Generator (PMSG) by sensor-less Field Oriented Control (FOC) method. Two methods of sensor-less FOC are proposed to control the speed and torque of the PMSG. The PMSG and the full-scale converter have an increasing market share in variable speed Wind Energy Conversion System (WECS). When compared to the Induction Generators (IGs), the PMSGs are smaller, easier to control and more efficient. In addition, the PMSG can operate at variable speeds, so that the maximum power can be extracted even at low or medium wind speeds. Wind turbines generally employ speed sensors or shaft position encoders to determine the speed and the position of the rotor. In order to reduce the cost, maintenance and complexity concerned with the sensor, the sensor-less approach has been developed. This study presents the sensor-less control techniques using the flux-linkage and the back EMF estimation methods. Simulations for both the methods are carried out in MATLAB/SIMULINK. The simulated waveforms of the reference speed, the measured speed, the reference torque, the measured torque and rotor position are shown for both the methods. © Maxwell Scientific Organization, 2014.