Abstract
Wind power systems in household applications adopt permanent-magnet synchronous generator, different from the induction generators powered by auxiliary power, for delivery of electric power under variable wind speeds. In the market, most front-end converters consisting of bridge rectifiers in series with a DC / DC converter exhibit poor power factor inherent with serious current harmonic distortion. In wind power systems, harmonic currents generate unbalanced load torque results in mechanical stress and vibrational noises. The objective of the thesis is to establish active front-end converter by using predictive current control in small wind power systems; the range of output voltage is set in several levels based upon input voltage and frequency so that current harmonics are reduced. The advantages of the controller are complete control, predictive control in current and fast response in tracking of the current accurately. In the controller, rotating synchronous reference frame of feedback control in frequency and phase can provide symmetric tracking structure. First, simulations in circuit are employed for analyzing the static and dynamic characteristics. Finally, 300W and 3kW rated small wind turbines are experimentally established for verification in improvement of vibrational noises, power factor, and current harmonics.