Field Adjustment Feature And Torque Feature Optimization Analysis Of Hybrid Excitation Flux-switching Brushless Ac Motor

To easily adjust the main flux, this paper presents a novel Hybrid ExcitationFlux-Switching Brushless AC Motor with a magnetic bridge structure. The motorwith both permanent magnet and field excitation coils on the stator has theadvantages of variable flux control capabilities by adjusting the DC excitationcurrent. At the same time, the machine has inherited Flux-Switching PermanentMagnet Brushless AC Motor’s advantages of high power density, high torquedensity, simple rotor structure and sinusoidal back-EMF. The operational principle,design optimization and performance of the motor are needed to study and verify. Inview of the above problems, this paper mainly has researched the following aspects:This paper first analyzes the generation mechanism of three-phase flux. Thestator pole and rotor pole number combination rules are deduced and the limitationof the original formula is pointed out. This paper establishes the basic circuit unitmodel of the hybrid excitation magnetic flux switching motor, and analyzes themagnetic variation with the change of electrical excitation MMF. Using themagnetic circuit equations to explain the regulation mechanism of flux andestablishing a mathematical model of the hybrid excitation magnetic flux switchingmotor. Excitation flux linkage equation and excitation voltage equation are deduced.Based on change regulation of the magnetic circuit and permanent magnet fluxswitching motor design ideas, a hybrid excitation magnetic flux switching motor isdesigned Successful. At the same time, flux, back-EMF, output torque, inductanceand static parameters were calculated and the influence of electrical excitation MMFon the back EMF, inductance, output torque and other parameters is analyzed. Wedraw a conclusion that hybrid excitation magnetic flux switching motor is not onlysuitable for brushless ac operation, but also has a strong ability to regulate the mainmagnetic field.Then this paper calculates and analyses the influence of the thickness ofpermanent magnet magnetization direction, the armature winding slot width and therotor pole arc width on cogging torque, back-EMF waveform, the output torque andtorque ripple by the finite element method. Then obtain a structural scheme thatkeeps small torque ripple and enhances the output torque. The influence of magneticbridge width and thickness of the stator yoke magnetic range on the magnetic fieldadjusting range is analysed. Two kinds of hybrid excitation structures that arewithout magnetic bridge and with magnetic bridge are compared on the performance.The hybrid excitation magnetic flux switching motor with magnetic bridge canimprove the magnetic field adjusting range, increasing the output torque, decreasemagnet eddy-current loss.Torque ripple of hybrid excitation magnetic flux switching motor mainly comesfrom the cogging torque. This paper studies finally the cogging torque reductionmethods of rotor-skewing, rotor tooth-chamfering, rotor tooth-notching and rotortooth-pairing. The rotor-skewing is the most competitive.