Electromagnetic Design And Analysis Of Low Speed Synchronous Motor With Dual-stator And Permanent Magnet/Reluctance Composite Rotor

With the advancement of major national strategic decisions of carbon peak and carbon neutrality,the green and low-carbon development of energy is regarded as the key in all walks of life,and the road of efficient utilization of resources and green and low-carbon development is unwavering.Low-loss,high-efficiency motors and their drive systems have become key research areas.Due to the advantages of high efficiency,high power factor,high torque density and wide speed range of the low-speed and high-torque motor direct drive system,it has been widely used in energy production,industrial power drive and other fields.Based on the project of National Natural Science Foundation of China,aiming at the large rotor space of low-speed and high-torque motor,a permanent magnet / reluctance composite rotor dual-stator low speed synchronous motor（PMRCR-DSLSSM）is proposed.In this paper,the theoretical analysis,electromagnetic design,prototype development and experimental research of the motor are carried out.The main research contents include the following aspects :（1）The structural characteristics and operation principle of PMRCR-DSLSSM are deeply studied,the connection mode of internal and external stator windings is analyzed,and the operation vector relationship between internal and external stators and composite rotors is expounded.（2）According to the structural characteristics and operation principle of PMRCRDSLSSM,the main size relationship of internal and external unit motors is deduced,and the power distribution principle of internal and external unit motors is proposed.The main size of internal and external unit motors is determined by using the mutual constraints of the main sizes of internal and external unit motors.The pole slot matching,stator winding design and permanent magnet size of the internal and external unit motor are analyzed.In order to improve the torque density,the effects of different reluctance rotor shapes and structures on the output torque and torque ripple of the inner unit motor are compared and analyzed.Based on the design principles and methods of the above motors,a set of optimal selection scheme of stator and rotor structural parameters of PMRCR-DSLSSM is determined.（3）The position relationship between the internal and external stators of PMRCRDSLSSM and the composite rotor is studied in depth.When the internal and external unit motors are running under the condition of maximum torque per ampere,the relative position of the internal and external stator winding axes and its corresponding rotor can be determined,and the design principle and manufacturing scheme of the internal and external stators assembly of PMRCR-DSLSSM are expounded.（4）Based on the electromagnetic design scheme of PMRCR-DSLSSM,the no-load characteristics and load characteristics of the motor are analyzed by finite element method,including no-load back electromotive force,air gap magnetic density,stator winding current,magnetic density cloud map,magnetic line cloud map,output torque and efficiency.The electromagnetic design scheme of the motor is proved feasible by simulation results.（5）Based on the electromagnetic design scheme of PMRCR-DSLSSM,a prototype is developed and experimentally studied.The correctness of the analytical method is verified by experimental results.