The Electromagnetic Design And Temperature Field Anslysis Of The Permanent Magnet Brushless DC Motor For Vehicles Application

With the development of science and the automotive industry, the motor’s power isincreased every year. However, the motor is limited by volume, resulting motor unitelectromagnetic load increases, the motor temperature rise problem is becoming more andmore prominent. The motor temperature rise problem is the primary factor of the motorproduction and operating, it relates to the life and operational reliability of the motor, so asmuch as possible to reduce the motor temperature rise and rational allocation of therelationship between the motor steady-state temperature rise and other indicators. Accuratecalculation of the temperature field of the motor, not only to ensure the safe operation ofthe motor, but also has important significance to improve the operating efficiency of thelarge units, optimize the design of the motor unit, and reduce the cost of motormanufacturing, therefore attaches great importance to the study of the problem in thedesign and operation.The thesis identifies the electromagnetic scheme of permanent magnet brushless DCmotor,and accords to the requirements of the motor parameters to determine the maindimensions of the motor. In this thesis using the finite element analysis software Ansoft tocalculate the magnetic field distribution in the motor steady-state operation, the air gap fluxdensity; and using the transient solver to calculate the no-load counter electromotive force,the cogging torque and calculate the motor speed, current, core losses and winding lossesfrom startup to stable operation of the process.The thesis studies the motor temperature field generated by the motor loss. Useing thefinite element software Fluent to analysis the three-dimensional temperature fielddistribution in the case of air-cooled, water-cooled two cooling method permanent magnetbrushless DC motor, and determine the motor temperature rise of the hottest spot.Three-dimensional model of motor is built in the finite element software, the complexmotor internal structureare meshed using the method of from outside to inside layered cutinto parts by Gambit, the quality of grids are guaranteed and the accuracy of calculation isimproved. By summarizing the simulation results obtained motor internal temperature risedistribution law, and winding ends are the temperature rise of the hottest spots in the twocooling mode; Second, the thesis summaries the law how the different cooling conditionsinfluence to the motor temperature rise in the same cooling mode; Finally, comparing the experimental results and simulation results, the temperature riseresults are consistent, the error is within the allowable range, and verified the correctnessand feasibility of the simulation method.