Research On Coupling Capability Of Brushless Doubly Fed Machine And Development Of Simulation Software

Brushless doubly fed machine (BDFM) is a novel AC machine, which has lots of advantages. It could operate in doubly fed mode without electrical brush. The BDFM needs smaller converter in capability because the power of the converter is slip power, therefore, it reduces the system cost. The multi-pole BDFM has higher reliability because of ignoring the gearbox. But the BDFM has several difficult problems, the weaker coupling capability results in lower power density and operation performance, the iron loss difficult to calculate currently, and the lack of the performance simulation software which is simple and convenient. These problems above mentioned are studied in this thesis.Firstly, utilizing the winding function method based on magnetic motive force and conductance, the inductance parameters of the BDFM with Axially Laminated Anisotropic (ALA) reluctance rotor are calculated. By modifying these design parameters, pole numbers, pole combinations and pole-arc factor of the ALA rotor, the corresponding inductance parameters can be calculated. The effects of the design parameters on coupling capability are studied by means of these inductance parameters. The conclusions can be drawn that the lager pole numbers and closer pole combinations and appropriate rotor pole-arc factor could all improve the coupling capability of the BDFM under the consideration of the BDFM design principle.Secondly, on the basis of analyzing the design principle of the BDFM, (12+8)-pole BDFM can be designed, the electromagnetism design is verified by the finite element analysis. The fine modulating function of the multi-pole rotor is researched in terms of the transient magnetic field analysis, and preliminary conclusion is drawn that ALA rotor can be replaced by common salient pole rotor when it is multi-pole. The no-load iron loss in different operation mode can be also calculated by the transient magnetic field analysis.Finally, the parameters calculation and performance simulation program are improved, and the characteristic of the prototype is simulated. The simulation software which the interface is friendly, the operation is simple and the calculation is rapid is worked out. The software has not only completed parameters calculation for two types of the rotor structure, but also finishes several simulations including the self-triggered and asynchronous operation, synchronous operation and doubly fed adjustable operation mode etc. The parameters of the BDFM could be all input from the interface, then the parameters calculation and simulation results are shown in the output interface by figure and could also be derived conveniently. The software is suitable for everyone who may not know the machine simulation. Therefore, it could provide the convenience for the further study and popularization application.