Electromagnetic Design And Performance Analysis Of Axial Flux Brushless Doubly-fed Reluctance Generator

Wind energy is an irreplaceable part in the field of new energy.The most important subject for wind turbines at present is making good use of wind energy.The instability of wind power and improving the stability of electric power through transmission have become technical problems for wind power generators.Therefore,it is very meaningful to design a wind turbine with the advantages of low-speed direct-drive,high power density,high reliability and economy,and easy maintenance for the development of wind power technology.Brushless doubly-fed generators do not need carbon brushes and slip rings,and they have the advantages of good economy,high reliability,small capacity of frequency conversion equipment and low cost.This thesis designs a new axial flux brushless doubly-fed reluctance generator with dual stator,distributed surround group and diamond magnetic resistance rotor structure with sinusoidal edge.This thesis mainly includes the following contents:Firstly,a kind of motor with double stator,distributed surround groups and reluctance rotor structure with sinusoidal edge diamond shape is proposed.The working principle of brushless doubly-fed wind turbine is introduced,and the influence of double stator structure,surround group and sinusoidal side diamond shape rotor on motor performance is analyzed.Besides,the magnetic field modulation mechanism and the energy flow relationship of the brushless doubly-fed motor are introduced,and the energy flow relationship diagram is drawn.Secondly,according to the traditional design method of brushless doubly-fed motor,the main parameters of the motor include pole embrace,stator slot number and rated parameters are determined.The three-dimensional motor is transformed into two-dimensional motor by the two-dimensional equivalent method of axial flux motor.Then the three-dimensional model is used to verify the rationality of motor size design.Finally,ANSYS Electronics Desktop finite element simulation software is used to establish the two-dimensional and three-dimensional finite element models of axial flux brushless double-feed reluctance generator.Although the amplitude of no-load back EMF decreases slightly,the waveform distortion and slot torque of no-load back EMF decrease to some extent.In this thesis,the no-load characteristic curve,magnetic field distribution and back EMF waveform are obtained by simulation analysis of the improved rotor motor under no-load operation mode.Meanwhile,when the motor works in the rated state,the loss and efficienty can be calculated.