Sensorless maximum power point tracking control in wind energy generation using permanent magnet synchronous generator

This paper proposes a control strategy for variable speed wind energy conversion system (WECS), incorporating maximum power point tracking (MPPT) algorithm, using direct driven permanent magnet synchronous generator (PMSG). The generator is operated in the speed control mode below the base speed by controlling the terminal voltage using three phase front-end active-rectifier feeding power to the DC bus. The voltage reference is dynamically varied based on the direction of active power change. The control algorithm is independent of turbine parameters as well as machine parameters. The proposed method obviates the measurement of rotor speed and wind velocity. Thus the resulting system has low cost and higher reliability. The control structure includes a voltage control loop for changing the speed of generator and consequently the wind turbine output power, and a current control loop to maintain unity power factor at the terminals of generator which improves efficiency of the system. The controller performance is validated through simulation results with various changes in wind velocity.