Nonlinear observer-based control for PMSG wind turbine

•A mechanical sensorless controller to a PMSG based WECS is introduced.•A nonlinear observer is used for estimating mechanical variables.•A MPPT strategy is achieved although mechanical sensors are avoided.

This paper introduces a mechanical sensorless control strategy to be used in variable speed wind energy conversion systems based on permanent magnet synchronous generators. The goal of the control strategy is to track the wind turbine maximum power point. With the proposed strategy, mechanical sensors are not needed to implement the control law. For this reason, electrical sensors -voltage and current sensors-are only needed to build the control law.In order to obtain estimates of the mechanical variables, a nonlinear Luenberger-like observer is designed. This observer only uses measurements of the electrical variables. The estimates are fed back to the controller in order to build the mechanical sensorless control strategy.The performance of the whole system is tested through simulations.