Research On Permanent Magnetic Gear Based On Motor Principles

Compared with mechanical gear boxes, non-contact magnetic gears have many advantages such as high efficiency, little noisy, easy lubrication, long lifespan, self-protection ability, and so on. However, the present magnetic gears have their own disadvantages, such as small gear ratio, low torque density, low permanent magnets utilization, and high-cost. This thesis, aiming to overcome present magnetic gear shortcomings mentioned above, focused on the research of brand new constructions of magnetic gears with big gear ratio, high efficiency, high torque density, high permanent magnets utilization, and low cost, in the transmission forms of coaxial and linear to rotation.First, the thesis introduced a novel coaxial permanent magnetic gear based on reluctant motor principles, and explained the running process. Analyzing the structure faults, the thesis purposed an improved structure that and pursued more stable transmission and higher torque with doubled stators and inner rotors. After mathematical modeling of the structure with equivalent current method and magnetic equivalent current method, the Finite Elements Analysis was done to simulate the example, which included3pair stators and1pair inner rotor pillar achieving25:1ratio transmission, and to calculate the electromagnetic field characteristics and the torque. With system theory, dynamic analysis was finished to illustrate the running process details.For the purpose of bilateral transmission with high ratio, the thesis introduced double layers stators permanent magnetic gears based on synchronous motor principles, and explained the running process. After mathematical modeling of the structure with magnetic equivalent current method, the Finite Elements Analysis was done to simulate the example, which included20pair high-speed-rotor pillars and1pair low-speed-rotor pillar achieving20:1ratio transmission, and to calculate the electromagnetic field characteristics and the torque. Improvement schemes were expounded from high speed rotor aspects, low speed rotor aspects, and stators aspects.In the form of rotation-to-linear transmission, a novel permanent magnetic gear was introduced in the last part of the thesis. After explaining the running process, mathematical modeling of the structure was purposed with equivalent current method and magnetic equivalent current method. The electromagnetic field characteristics analysis and the torque calculation were finished by Finite Elements Analysis method. Improvement schemes were expounded from teeth structure, permanent magnets on the rotor, and spiral structure.The novel design is an integration of the advantages of high efficiency of PM motor, and high positioning accuracy from reluctance motor. In this thesis, the new constructure, new modeling and dynamical analyzing methodology was devoloped. Both the designs and the analysis method have very valuable practical significance.