Different torque ripple reduction methods for wind energy conversion systems using diode rectifier and boost converter

A conventional small-scale wind energy conversion system consists of a permanent magnet synchronous generator, a diode rectifier, a boost converter, and a grid-side inverter. Since the generator stator currents cannot be controlled independently using a diode rectifier, relatively large electromagnetic torque ripple results caused by the low frequency generator stator harmonic current. The torque ripple may cause detrimental effects on the turbine and shaft life time. This paper proposes different torque ripple reduction methods based on the conventional structure, by improving the control strategy. The features of different methods are discussed and compared. It is shown that the torque ripple can be significantly reduced by implementing simple control strategies. The results are confirmed by MATLAB/Simulink simulations and practically.