Control Study Of Brushless Double-Fed Wind Power Generator Based On Matrix Converter

Wind power generation have become a quickest increasing frontier in the world energy field because of its merits such as: green,clean,environmental protection,renewable etc. This article introduced the actuality and development of wind power generation in brief. On the basis of having analyzed the actuality and trend of wind power generation technology, a new control mode of wind power generation of Brushless Double-Fed Machine (BDFM) based on AC-AC Matrix Converter (MC) was proposed. It resolved the problem of low efficiency and big cubage which caused by the DC link in the middle of AC-DC-AC converter which was widely used on business in wind power generation system controlled with variable speed constant frequency(VSCF) at the present time. Moreover, BDFM is very suitable for wind power generation in formidable natural conditions since it has no slip-ring and brush which bring a high reliability.This article introduced the developing process,actuality and study status of BDFM and MC in brief. On the basis of the basic structure and theory of BDFM, the realization of wind power generation controlled with VSCF was analyzed. The mathematic model under d-q reference frame was found based on the fundamental equations of BDFM, then, the steady-state equivalent circuit was deduced, and its characteristics such as: electromagnetism relationship and rotate speed,power,energy transmission,efficiency and power factor etc. , were analyzed in detail. MC is used as the excitation converter of BDFM, after having introduced the topological structure and basic principle,the types of bidirectional switch and the ancillary protective circuits of MC in brief, its modulation method and commutation strategy were analyzed in detail, and the indirect space vector modulation and four-step commutation strategy were adopted. Then, a simulation model of MC was found and the simulation results have been analyzed. The simulation results showed the validity and feasibility of the adopted modulation method and commutation strategy.On the basis of having realized the decoupling between power winding and control winding both of which been twisted on the stator of BDFM by using the conversion relationship of d-q reference frame and synchronous reference frame, the strategy of controlling active power and reactive power individually was proposed. Then, a double closed loop system of VSCF wind power generation of BDFM based on AC-AC MC was designed; furthermore, its active and reactive power control and the IGBT drive part were analyzed in chief. Based the previous theory analyses and the successful simulation for MC, the system simulation model was found, and the simulation analyses were done under the synchronous speed simply. The simulation results validated the validity of the system and its control strategy, studying and developing this power generation system that composed with MC and BDFM will be a deeply potential mode in VSCF wind power generation field and valuable in theoretical study and practical application.