A novel maximum power point tracking algorithm for a stand-alone unity power factor wind energy conversion system

A novel control strategy for the operation of a permanent magnet synchronous generator (PMSG) based stand alone variable-speed wind energy system is presented in this paper. The direct drive PMSG is connected to the load through a unity power factor current-controlled rectifier, which offers features such as high power factor operation, voltage regulation ability, low switching voltage stress and reduced component count of switches, compared to the conventional front-end diode rectifier topology. The developed MPP control strategy, based on a combination of incremental conductance and hysteresis current control, is capable of modifying the current drawn from the generator in order to affect the electrical torque and achieve rotor-speed control of the wind-turbine. This control system is capable of meeting three vital objectives viz. maximum power point tracking, high power factor and high quality input current with reduced harmonic distortion. Multiple simulations have been performed using PSIM and the results show that the controller is capable of achieving the system objectives and performs very well during dynamic and steady state condition.