| Under the current technical level and application conditions, hybrid electric vehicle (HEV) has become a leader in new energy vehicles in recent years due to its power assembly, energy efficiency and low pollution. However, the structures of electric brush and slip ring of the motor in the vehicle bring a great security risk. It increases the contact resistance, the electric brush and the slip ring often generate heat due to poor contact when the excitation current increases, which would cause the annular fire and burn out the brush holder when it is serious. Temperature rise will cause instability to the structure. Thus the fault rate is high. In addition,the carbon dust produced by the brush will cause a certain impact on the environment,and it is easy to bring hidden troubles to the safe operation. At the same time,the brush in the working process often causes the high frequency electromagnetic interference to ECU,which worsens the electromagnetic environment of the motor system and brings serious electromagnetic interference to the drive system.In order to solve the above problems, based on inductively coupled power transfer(ICPT) technology, this dissertation applies it to the motor brushless excitation by using the advantages of energy transmission based on no electrical contact, so that it can maximize the avoidance of security risks brought by brush and slip ring on the motor operation. In this dissertation, basing on inductively coupled power transfer technology, considering loosely coupled rotating excitation transformer (LCRET) as the core, the overall design of the contactless excitation heterogeneous system (CEHS) is a new type of brushless excitation system. It can replace the brush and slip ring in the traditional excitation system, so as to realize the real meaning of brushless excitation. Meanwhile, it has the advantages of reducing the weight of the motor, improving the reliability, reducing the cost, bringing more simple motor structure and wider speed range.Firstly, the technical field and key technology of contactless excitation heterogeneous system is summarized, the brushless excitation of motor and inductively coupled power transfer technology is presented. Research status,application fields and the latest developments of the two parts are introduced in detail.The overall structure of the contactless brushless heterogeneous excitation system is presented, electromechanical integration installation scheme is designed according to its operation mechanism. Winding topological physics model, magnetic resistance model and equivalent circuit model of adjacent and coaxial loosely coupled rotating excitation transformer are established respectively. In order to optimize the design of loosely coupled rotating excitation transformer, models of fully coupled ideal state and excitation inductance are given. The calculation process of magnetizing inductance and leakage inductance is described, and the magnetic circuit with leakage inductance is analyzed in detail, the leakage inductance model and mutual inductance model of loosely coupled rotating transformer are presented. The optimal design of the adjacent winding method is given The definition of the coupling coefficient and the loss model are given at final. The adjacent and coaxial actual winding schemes are given by using the Litz line. In view of the equivalence between the heterogeneous system and the wireless power transmission, verification is performed by ANSOFT MAXWELL simulation platform. On the basis of the above analysis, the optimal winding topology of contactless excitation heterogeneous system is given. Aiming at the efficiency problem caused by leakage inductance, the performance analysis of different resonance compensation strategies for contactless excitation heterogeneous system is analyzed by the first harmonic approximation(FHA) based on MATLAB simulation platform. After comparing the gain and performance of various resonant compensation, a resonant compensation strategy for a contactless excited heterogeneous system is given. In order to solve the problem that the control of loosely coupled contactless excitation system is complex,the generalized state space averaging (GSSA) model is used to simplify the complexity of the circuit model caused by the loosely coupled rotating excitation transformer, and the rationality of the model is verified. On this basis, the active disturbance rejection control (ADRC) algorithm is used to control the contactless excitation heterogeneous system, and the simulation results verify the feasibility of active disturbance rejection control. Aiming at the electromechanical integration of contactless excitation heterogeneous system, the half bridge inverter part, the full wave rectifier part, the resonance compensation part and the driving part of the contactless excitation heterogeneous system are designed roundly. The test prototype of contactless excitation heterogeneous system is built, which is mainly used in the following: The output characteristics of LCRET under different topologies, the feasibility of the proposed optimal winding topology are proved from the experimental point of view. This dissertation gives out the power generation characteristics, efficiency curve, temperature rise curve and analysis of results.Finally, the main research work and innovative achievements are summarized, and some suggestions and prospects for further research are put forward.The contactless excitation heterogeneous system does not occupy the additional volume of the motor, and does not change the main structure of the original motor.The excitation system can be applied to the electric excitation brushless motor. It has the advantages of reducing the weight of the motor, improving the reliability,reducing the cost, bringing more simple motor structure and wider speed range and can also be applied to the brushless motor with compound excitation. Contactless excitation heterogeneous system provides a new idea for brushless excitation. |
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