Sensorless control of PMSG–based wind energy conversion systems using a FLL–based synchronization technique

Abstract

The continuous and accurate information of generator speed in wind energy application is an essential requirement in order to get the maximum power at given tip speed ratio, since the maximum power is almost an cubic function of generator speed. This paper studies a Frequency Locked Loop (FLL) - based controller for estimating the rotor speed of the Permanent Magnet Synchronous Generator (PMSG) in a Wind Energy Conversion Systems (WECS). The proposed system consist on get the direct sequence component of generator voltage by means a Dual Second Order Generalized Integrator (DSOGI) and applying a FLL for estimating the generator frequency and, hence, its rotor speed. Using a Proportional Resonant (PR) control, the rotor position is not required and thus a lot of mathematical operations are avoided. Simulation using MATLAB/Simulink and PowerSim shows that using a FLL leads to a simpler and reliable sensorless technique.