Research On Electromagnetic Design Of Cylindrical Arc Permanent Magnet Motor For Large-Aperture Astronomical Telescope

In the process of human exploration of the universe,higher requirements are proposed on astronomical telescopes.The astronomical telescope is developing in the direction of long detection distance,high precision and wide range.This requires a high torque and high control accuracy of the corresponding drive unit.In this paper,the electromagnetic design of arc motor for large-caliber astronomical telescope is carried out,with the adoption of direct-drive operation mode to meet the development reequirements of large-caliber astronomical telescopes.The paper analyzes the research status at home and abroad and proposes a cylindrical arc permanent magnet synchronous motor(CAPMSM).The CAPMSM is taken as the research object,based on which the working principle,winding design,structure optimization,torque fluctuation suppression and electromagnetic characteristics are carried out.The main work of the thesis includes the following aspects:(1)This paper introduces the development history of large-scale astronomical telescopes,summarizes the research status of the driving methods of large-diameter telescopes,the application status of arc motors for large-diameter telescopes,and the research difficulties of arc motors for telescopes.(2)Based on the analysis of the structure and working principle of the CAPMSM,the design steps of the CAPMSM are given,and the basic size of the motor is determined.(3)The connection method of cross windings is proposed to solve the problem of spatial asymmetry of three-phase windings.The finite element analysis(FEA)method is used to verify the effectiveness of the connection mode of cross windings in suppressing torque fluctuations.(4)The effects of air gap length,slot-opening width and pole arc coefficient on reluctance torque are analyzed.The fractional slot structure,the circumferential arc angle of a single rotor,the space arc angle between multiple rotors,and Halbach magnetization are proposed to achieve the purpose of reducing motor torque fluctuations.(5)The electromagnetic characteristics of the optimized model are analyzed.The simulation results verified that the optimized model has better torque characteristics and lower harmonic distortion rate of no-load back EMF.