Research On Optimal Design Of Rotor And Speed Sensorless Of Bearingless Slice Motor

The development strategy of “made in China 2025” makes detailed plans for the future development of manufacturing related fields,and promotes the further upgrading of manufacturing industry.It also puts forward higher requirements for electrical transmission equipment in China.With the shortage of rare earth materials,how to use less permanent magnets to meet the requirements of motor performance has become an important part of motor design.In order to solve the problems of low torque density and low power density in the bearingless synchronous reluctance slice motor(BSyn RSM),a permanent magnet-assisted bearingless synchronous reluctance slice motor(PMa-BSyn RSM)structure is proposed in this dissertation which can improve the torque density and power density of the BSyn RSM.The PMa-BSyn RSM combines the advantages of synchronous reluctance motor,magnetic bearing and slice rotor,it is a new type of bearingless motor,which can suspend the rotor in five degrees of freedom.The PMa-BSyn RSM has the advantages of no friction,no lubrication and easy to maintain.It has important value and application prospects in the biological medicine,aerospace,life sciences,semiconductor industry and other fields.The traditional speed sensor increases the volume of the motor,which increases the cost of the system,and reduces the reliability of the motor under high-speed operation.The speed sensorless method without speed sensor can effectively solve the caused by traditional speed sensor.Funded by the National Natural Science Foundation of China(51675244,61973144)and the Jiangsu Provincial Key Research and Development Project(BE2016150),this dissertation takes the PMa-BSyn RSM as the research object,the working principle of the motor,mathematical model,rotor optimization design,and speed sensorless are studied.The main works are as follows:1.The research background and significance of the bearingles slice motors are clarified,the research status of bearingless slice motors at home and abroad are concluded and reviewed,and the development status of bearingless motors speed sensorless are analyzed.After the basic structure and working principle of the PMa-BSyn RSM are analyzed,the mathematical model of the PMa-BSyn RSM is derived.2.In order to solve the problems of low torque density and low power density in the bearingless synchronous reluctance slice motor,the PMa-BSyn RSM structure is proposed.Based on the finite element analysis,the rotor magnetic barrier parameters and the auxiliary permanent magnet parameters are optimized.The electromagnetic characteristics of the optimized PMa-BSyn RSM and the traditional bearingless synchronous reluctance slice motor are compared and analyzed in terms of torque,suspension force and power factor.The result shows that the torque density and power factor of PMa-BSyn RSM are effectively improved after optimization.3.In order to solve the inherent shortcomings of the traditional speed sensor in the stable operation of the PMa-BSyn RSM,the soft measurement of the rotational speed is analyzed.Based on the principle of neural network and the principle of left inverse,a speed observer is designed to realize the observation of rotational speed,and a speed sensing model based on left inverse of neural network is derived.The designed speed observer is applied to the direct control system for simulation verification.The results show the feasibility of the proposed speed observer.4.A digital control experimental platform with DSP as the core is constructed,and the hardware circuit design and software control algorithm of the motor control system are designed respectively.The experimental research on the experimental platform shows that the motor can be suspended stably and has certain anti-interference ability.Based on the BP neural network,a speed sensorless test scheme is designed.