A cost-effective sensorless variable-speed wind energy system

Due to deterioration of fossil fuel and policies on greenhouse gas mitigation, wind energy systems (WESs) has gained traction as one of the most promising renewable energy systems for electric power generation during the past years. At a specific wind speed, the captured wind power by WES is a function of wind turbine speed. Only when the turbine rotates at optimum speed can the maximum power be extracted from the wind. Therefore, the maximum power point (MPP) tracking (MPPT) technique is important for wind energy conversion systems. To achieve MPPT control, the generator speed measurement is needed in each moment. Using a rotor speed sensor for this purpose poses some obstacles to practical implementation and has an impact on drive´s cost, machine size, reliability, and noise immunity. In this paper a cost-effective sensorless reduced switch count PMSG based wind energy system is proposed in which the generator speed is estimated by an observer method. Simulation results are presented to verify the performance of the proposed wind energy system under steady state and transient conditions.