Design And Analysis Of Brushless Excitation Technology Of Wound Field Synchronous Machine With Rotating Electro-Magnetic Coupling Resonators

Permanent magnet synchronous motor has the advantages of high power density,compact structure and high efficiency,which is widely used in the fields of wind power generation,electric vehicles and rail transit.However,it is difficult to regulate the excitation of permanent magnet synchronous motor,and it is difficult to realize excitation protection in case of fault,so the development is limited.In addition,the price of rare earth permanent magnet materials is expensive,and the cost of permanent magnet motor is relatively high.More and more experts and scholars pay attention to the development of the wound field synchronous motor because it does not need rare earth materials,has low cost and has adjustable excitation field.In order to realize the brushless excitation of the wound field synchronous motor,this thesis proposes brushless wound field synchronous machine with electro-magnetic coupling resonators and carries out theoretical analysis,numerical simulation and experimental verification of the system structure,resonance characteristics,load characteristics and system efficiency.On the basis of combing and summarizing the existing literature,this thesis points out the shortcomings of the technology and method of the brushless excitation of the wound field synchronous motor,puts forward the introduction of the radio energy transmission technology into the wound field synchronous motor to establish the non-contact transmission and control method of the excitation energy,and gives the specific structure configuration and implementation form.This thesis carrys out the electromagnetic design of wound field synchronous motor,magnetic coupling resonator and its accessories,and analyzes the basic topological structure of the magnetic coupling resonator,establishes the two coil model of series connection structure,and constructs the design method and design criteria of the magnetic coupling resonator suitable for the excitation energy transmission of the wound field synchronous motor.Based on the circuit theory,the spatial state equation of the magnetic coupling resonator is established,and the transmission characteristics of the magnetic coupling resonator with different loads are studied.Based on the theory of electromagnetic field,the finite element simulation model of the magnetic coupling resonator is established,and combined with the external circuit,the joint simulation calculation is carried out to analyze the influence of load form on the resonance state of the system.The electromagnetic field numerical calculation is carried out to reveal the spatial magnetic field distribution of the magnetic coupling resonator and guide the structure design and efficient operation of the magnetic coupling resonator.According to the mathematical model of the magnetic coupling resonator and the wound field synchronous motor,the simulation model of the brushless wound field synchronous motor system is established in MATLAB software,and the simulation analysis of no-load and load conditions is carried out to verify the feasibility and control ability of the excitation energy transmission of the brushless wound field synchronous motor.According to the results of electromagnetic design,a prototype is made,and the experimental platform of the system based on the magnetic coupling resonator is built to test the system parameters and performance under static and dynamic conditions as well as no-load and load conditions.The experimental results show that the efficiency of the excitation device is more than85% under no-load and load conditions,which verifies the feasibility of the method,the rationality of the structure of the excitation device and the control ability of the excitation current.