Design And Calculation Of Electromagnetic Systems Of A Novel3-DOF Deflection Type PM Motor

With the rapid development of industrial automation technology, themulti-degree-of-freedom motion has become a major requirement for the actuators.Traditional multi-DOF motion requires the coordination and cooperation of manysingle-degree-of-freedom systems, which not only has large volumes, what’s more, butalso the precision and efficiency are not guaranteed. In this paper, a new novel3-DOFdeflection type PM motor has been proposed that can meet the requirements of the peoplefor the multi-DOF actuators. Compared with traditional actuators, this new type motor hasgreater improvement on efficiency and stability due to the replacement of excitationwindings by the permanent magnet to implement the spatial3-DOF motion. The structureand working principle of this novel3-DOF deflection type PM motor are introduced inthis paper. The electromagnetic system, torque and kinematics models of this motor havebeen established in spherical coordinates. In addition, the performance parameters of themotor are optimized. The novel3-DOF deflection type PM motor has a broad applicationprospects and its studies have become a new research direction of motors.The main contribution of this dissertation contains following aspects:1) A kind of new novel3-DOF deflection type PM motor with double-layer statorcoils, single-layer PM rotor structure is presented. On the basis of its spin rotation, thismotor can implement proper deflection motions. The structure and working principle ofthe motor has been introduced in detail.2) The electromagnetic system and torque models are established by analytical andfinite element methods. The relationships between flux density and three motion anglesare derived by the method of separation of variables, and the spin and deflection motions’torque models are built with the Lorentz force law. The adopted finite element methodmodels and simulates the motor by Ansoft Maxwell to derive the air-gap flux density andtorques’ simulation results. Comparing the two models created by the two methods, theelectromagnetic system model has been corrected and improved.3) The dynamics model of this3-DOF deflection type PM motor is established toanalysis the relationships between the three movement angles and time by positivesolutions, and then the motion trajectory of the rotor is observed and its back-EMF modelhas been built. Through the establishment of the dynamics and back-EMF model, the internal parameters of the motor are linked with its performance, which lays thefoundation for the studies of the rotor position detection and control system.4) The impact of parameters on the motor performance is analyzed by the builtelectromagnetic system model. The parameters of the motor have been preliminarilyoptimized by analysis on the number of poles, internal and external diameters, height andthe magnetization direction of the rotor. The further optimization objective is determinedas the air-gap flux density. Genetic algorithm is used for optimization by choosing therotor internal and external diameters and the latitude angle of the rotor as the optimizationparameters, with the PM material usage as the constraints. The optimization model hasbeen developed and compared with initial model.5) On the basis of the original rotor structure, two improved structures of rotor aredeveloped and proposed by analyzing the established electromagnetic system anddynamics models. The analysis and studies on the performance of the new structures havebeen carried out, which provides the direction for further optimization of this kind ofmotor.