A Novel Wind-Power Generating System Using Field Orientation Controlled Doubly-Excited Brushless Reluctance Machine

Variable speed operation of a wind turbine generator improves its energy capturing capability. Up to the present, the machines employed have been induction machines, conventional synchronous machines or DC machines. The major drawback of these machines is that a complicated arrangement of slip rings or commutators with brushes, and a full-rating power converter are required. Reliability and cost are major concerns for these systems. Slip power recovery system with a doubly-fed wound rotor induction machine uses a converter with substantially reduced power rating, yet the slip-ring and brushes are still required. A new variable speed constant frequency wind power generating system is proposed in this paper by using a doubly-excited brushless reluctance machine. A field orientation control method is proposed to track the optimal torque-speed profile of the wind turbine and to realize flexible reactive power control. The proposed wind power generating system has potentials of high efficiency, good flexibility and low cost.