Temperature Calculation And Cooling System Design Of Permanent-Magnet Electric Motors

The performance targets of permanent-magnet electric motors are prominent,compared to other type electric motors.Permanent-magnet electric motors will be applied every industry widely.Because the developing tendencies of permanent-magnet electric motors are high-capacity , high-power density and small volume . It makes divergences between the temperature rise and other performance targets of permanent-magnet electric motors. In order to solve these problems,it must design the cooling system properly and calculate temperature. The temperature rise of permanent-magnet electric motors not only considerate the stator winding but also permanent magnetism at the same time.The thesis descrips the temperature calculation and the cooling system design as follows:First,the thesis analyzes the thermal field according to electromagnetics,heating, fluid and so on. It calculates and analyzes the temperature field of radial permanent-magnet electric motors.Making use of the equivalent thermal network model,meshing the finite-element,centralizing the parameter ,listing a set of conventional semi-empirical equations and solving the temperature of each nodes. When it ascertains that the medium in electric motors and heat-transfer coefficient of related components,it will respond to the experience formulas.Second,from the quality,it explains the loss distribution for the radiul electric motors and makes differences between slot inner winding loss and end-winding loss.From the theory,it makes analyses between stator yoke loss and stator teeth loss to decrease the errors.The thesis makes use of ANSYS,ANSOFT softwares,takes advantage of the finite-element method to analyse the thermal field of permanent-magnet electric motors,with steady and transient stage.At last, it makes analyses TYJS electric motor with machine tools.The results are satisficated between calculated and measured temperatures.At last,it analyzes the thermal field of a disk electric motor , which 5kW-450 two stator and single rotor .Because of the differences between radial electric motor and disk electric motor.Explain the loss distribution,heat-transfer coefficient and so on respectively for disk electric motors and radiul electric motors.The cooling system design of disk electric motor uses assumption coefficient, deduces fan structure ,designs the cooling system of the electric motor rationally .According to those,it may calculate the temperature of the electric motor ,and reache the maximum. It is convenient to improve and develop the prototype.