Study Of BDFM With A New Type Reluctance Rotor And Its Application

The Brushless Doubly-Fed Machine (BDFM) shows commercial promise as a variable speed drive or generator. However, for this promise to be realized the design of the machine must be improved beyond that proposed to date. This dissertation contributes towards this goal through machine analysis, parameter calculation and performance research. The main work and innovation points are as follows:1.This dissertation analyzes the special cage, stator and rotor structure of reluctance and winding BDFM and operation principle of the motor, and then based on the asynchronous operation of BDFM synchronous motor characteristics, combing the reluctance structure and wound rotor to give full play to advantages of these structures. Proposing winding rotor structure having an auxiliary reluctance BDFM. This kind of rotor structure combines two existing structures of reluctance and wound rotor, while maintaining the wound rotor winding wiring is very flexible, but also make reluctance played a leading role for magnetic flux, improving magnetic field modulation effects of the motor, it can achieve a good coupling of the rotor and the stator winding sets to maximize capacity.2. According to rotor structural characteristics of the new reluctance BDFM, two axes was given first:the axis of the maximum reluctance path(shaft m)and the axis of minimum reluctance path(shaft n). Different from the conventional motor, the electrical angle of shaft m and shaft n is not perpendicular to each other. Winding magnetic motive force of three-phase power of stator decomposes the decoupling of shaft m and shaft n, three-phase controls winding magnetic motive force to make sure decoupling can also be achieved by the same method, and then deduce mathematical model of the rotor synchronous speed BDFM.3.To get BDFM equivalent circuit, this dissertation makes a detail analysis of new reluctance BDFM. Based on the similar magnetic field modulation of wound rotor and reluctance rotor, and seeing from the electromagnetic coupling relationship between power winding and control winding of stator, the steady state equivalent circuit of new reluctance BDFM can be calculated direct by method of results on both sides,which on condition that without the need for internal electromagnetic process research, the rotor winding currents and other variables.4.The key parameters affecting the coupling capacity of BDFM are analyzed, such as pole arc factor, ratio of magnetic isolation layer and magnetic layer, magnetic layer numbers,conductors series,the relative position between salient axis and winding axis, winding connection and so on.In order to ensure uniformity of parameters, here keep the stator side are exactly the same, the final size of the new structure of new mixing rotor and lower new winding of high harmonics of BDFM has been optimized.5.Researches and presents basis for slot conjugation and pole number selected of BDFM,and what pole match affect on motor performance. Analysis the effect of the new BDFM main dimension by the electrical load and magnetic load, and then analyzed the condition to minimizing motor size,but also increase power density of BDFM within the electric, magnetic load allowable range.6. Analyzing to 1/3 new reluctance BDFM, radial electromagnetic force wave of fundamental field has been proved to be the main reason to make BDFM transform. Using finite element simulation, and comparing the Fourier analysis results and theoretical analysis, the rationality of rational analysis was proved.At last, on the basis of YZR25, designed a 30kVA system prototype of brushless doubly-fed by wind power, and a detail analysis for the BDFM utilization in wind power has been done, prototype is verified by simulation and prototype experiment of no-load and load characteristics.