| The permanent magnet brushless DC motor has a simpler rotor structure and higher efficiency.High-speed motors have many advantages over common motors,such as large power density,small size,and high efficiency and so on.However,due to these characteristics,it has problems such as the fact that the temperature is more likely to rise and the heat emission is more difficult.This paper is based on mastering the design theory of high-speed permanent magnet brushless DC motor,and design three 10 kW and 10000r/min permanent magnet brushless DC motors of different rotor structures.One is embedded and the other two are surface mount permanent magnet brushless DC high speed motors that have different types of rotor-sheathed.The comprehensive comparison analysis of the three motors are represented in the following aspects.The content of this paper is as follows:Firstly,the electromagnetic field of high speed permanent magnet brushless DC motor with different rotor structures is designed.The background and significance,the current status of research at home and abroad,the research content of the paper and the structure of the paper are described.Then the high-speed permanent magnet brushless DC motor studied in this paper is designed according to the characteristics of high-speed motor.Then the electromagnetic design of high-speed permanent-magnet brushless DC motors of two rotor structures was performed by finite element software for electromagnetic design,and the no-load and load characteristics of the two rotor structures were analyzed through finite element simulation to ensure the reasonable design of the motor..Secondly,the mechanical strength of the rotors of high speed permanent magnet brushless DC motors with different rotor structures was analyzed.In order to prevent permanent magnets from being damaged by high tensile stress caused by high-speed rotation,embedded rotors and surface mount rotors are designed.One is to embed permanent magnets in the rotor,and the other is to give different materials to protect the permanent magnets.Based on elasticity mechanics and finite element,the three-motor rotor strength model was built by using the finite element of ANSYS Workbench software.The stress distributions of the three rotors were calculated and combined with the temperature of the rotor during actual operation.The phenomena of rising and rotating speeds have analyzed the strength of variousparts of the rotor at different temperatures and different rotating speeds to ensure the normal operation of the rotor.In addition,the loss of each part of the high speed permanent magnet brushless DC motor with different rotor structures is analyzed.The calculation of stator iron loss of high-speed motors needs to consider the effects of harmonics and rotation magnetization;calculate the copper loss of the windings using the formula method;establish a calculation model of wind and friction loss on the rotor surface and calculate,and then consider the rotational speeds of different rotors,rough surfaces of different rotors.The influence of degree on the surface friction loss of the rotor;the calculation of eddy current loss is calculated by Ansoft finite element software,and the eddy current loss of high speed permanent magnet brushless DC motor with different rotor structures is compared and analyzed.Finally,the temperature field analysis of high-speed permanent magnet brushless DC motor with different rotor structures is designed.A more reasonable and effective motor cooling system scheme is designed.The temperature distribution of the motor parts with different rotor structures under the program is analyzed by the ANSYS Workbench software.The maximum temperature of the high motors was significantly reduced,and the maximum temperature distribution of the three motors was obtained.At the same time,the influence of different inlet wind speeds on the temperature rise of the motor was analyzed. |
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