| The high speed permanent magnet motor has the advantages of simple structure,high efficiency and high power density.It can save the direct connection between the speed change device and the load,and has high reliability.Therefore,high speed permanent magnet motor has a wide application prospect in flywheel energy storage,high-speed motorized spindle,micro gas turbine and other industrial fields.In this paper,flywheel energy storage as the application field,high speed permanent magnet motor is the core component of flywheel system,and its research is of great significance to the development of flywheel energy storage.Aiming at the critical issues in a vacuum environment,such as energy storage and energy storage density,flywheel motor rotor structure and loss.This article conducts systematic research and analysis from the comprehensive design method,rotor loss,rotor strength,and motor temperature rise of high speed permanent magnet motor.The specific contents are as follows:(1)Aiming at the special characteristics of high-speed permanent magnet motors for flywheel energy storage,in this paper,based on a 350 k W,36000 r/min high speed permanent magnet motor,which integrates multiple physical fields such as electromagnetic field,intensity field and temperature field to comprehensively design the motor rotor.A composite fiber soft magnetic rotor structure with a radial integration of the flywheel body and the high-speed motor rotor is proposed.The Halbach magnetization method is adopted,and the rotor is ironless,which greatly reduces the loss of the motor rotor.(2)The structure of the composite fiber soft magnetic rotor is described in detail.ANSYS Maxwell,a professional electromagnetic analysis software,is used to analyze the influence of the number of unit layers and the content of mixed magnetic particles on the electromagnetic performance.The corresponding laws are summarized and the main technical parameters of the motor are determined.The electromagnetic characteristics of motor are simulated and analyzed based on the finite element method to verify the rationality of the electromagnetic design.(3)In this paper,the generation and influence of air gap harmonics are analyzed.The influence of slot size and air gap length on the harmonic size and harmonic content in the air gap magnetic density of the motor is analyzed in detail by using the transient field.Combined with the change of eddy current density in the composite magnetic fiber,the variation law of eddy current loss of the rotor is revealed.The size of air gap magnetic density produced by different unit layers is studied,and the distribution law of eddy current loss of rotor is analyzed.(4)In order to ensure the safety of the rotor at high speed,the strength of the rotor is analyzed in detail.The analytical calculation formula of rotor stress of high speed permanent magnet motor is given,and the physical properties of composite magnetic fiber material are predicted.The stress distribution of rotor at static and rated speed is calculated by ANSYS Workbench,and the influence of speed,interference and sheath thickness on rotor stress is analyzed.(5)Aiming at the special temperature rise of flywheel high speed permanent magnet motor,the radiation heat dissipation model under vacuum environment is established,and the temperature rise of the motor was calculated using the computational fluid dynamics(CFD),and the temperature rise of the motors was checked.The influence of cooling water flow velocity and rotor eddy current loss on the temperature rise of the motor is analyzed. |
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