| With the direct-drive technology having attention in the field of agricultural equipment drive field,more and more scholars at home and abroad focus on the research in the field of the machine with low-speed high-torque capacity.The traditional permanent magnet vernier machine with low speed and high torque characteristics is divided into stator and rotor type permanent magnet vernier machine.Permanent magnet utilization of stator-type permanent magnet vernier machine is not high,rotor-type permanent magnet vernier machine heat caused by irreversible demagnetization will lead to degradation of the machine performance.To solve the problem of the original permanent magnet vernier machine,this paper presents a three-phase high-torque density mixed magnetic material dual-permanent-magnet-excited vernier machine,which is embedded with permanent magnets in stator and rotor,and adopts mixed magnetic material,make full use of the internal structure of the machine.The contents of this paper are summarized as follows:1.The structural characteristics and working principle of magnetic field modulation magnetic gear are expounded and the working principle and structure characteristics of permanent magnet vernier machine are described.The principle of modulation is analyzed by mathematical analysis of air gap flux density.Finally,the modulation principle is explained by the simulation results of a permanent magnet vernier machine model.2.The selection of important parameters of the basic model of the machine is described,including the choice of the machine windings and the number of slots and the number of windings and the number of modulated teeth.3.A new type of high torque density permanent magnet vernier machine is proposed,which does not affect the modulation effect.The machine has the permanent magnets embedded in the stator and the rotor part,the stator and the part of the rotor are involved in the modulation effect.The magnetic field produced by the permanent magnets of the stator and the rotor section is modulated by the modulated teeth.The permanent magnets embedded in the stator section utilize the magnetization characteristics of the Halbach arrays,which reduces magnetic flux leakage to improve the utilization of permanent magnets and proposes the introduction of magnetic barriers at the bottom of the halbach magnetization arrays.4.Based on the study of the basic model,a high torque density permanent magnet vernier machine with external stator type is proposed.The machine adopts single layer fractional slot and concentrated winding.The optimization process of the machine is introduced in detail,including the determination of the direction of the permanent magnet,the combination type of the mixed magnetic material,the thickness of the permanent magnet,the width of the slot and so on.5.The simulation results of the prototype model are compared with the simulation resuluts of Maxwell,so the performance of the machine is verified by the joint simulation.6.Complete the design and manufacture of the prototype.The basic performance of the machine is tested by using the existing equipment in the laboratory,and the theoretical results of the theoretical simulation are verified by the experimental results. |
