Prediction And Measurement Of Rotor Temperature Distribution Of Permanent Magnet Synchronous Motor

In recent years,with the advantages of high power density,high efficiency and high power factor,permanent magnet synchronous motor(PMSM)have been widely used in various fields of industrial production and life.When permanent magnet synchronous motor is running,especially the permanent magnet synchronous motor with high torque density and high power density,there is substantial eddy current losses in the rotor,so the temperature of permanent magnet may be too high,leading to permanent demagnetization.Therefore,the prediction and measurement of rotor temperature distribution of permanent magnet synchronous motor is of great significance to optimize the design of permanent magnet synchronous motor and ensure the safe operation of motor.In this paper,the permanent magnet synchronous motor is designed and manufactured for prediction and measurement of rotor temperature distribution.The loss of the motor is calculated by the combination of experimental measurement and finite element analysis.Based on the structural dimensions of the experimental motor,the three-dimensional temperature field and fluid field simulation model are established.The simulation parameters of the motor in three different conditions are analyzed and calculated.With computational fluid dynamics software Fluent,the steady-state temperature distribution of the motor,especially the rotor temperature distribution,under various conditions is calculated.Then on the base of these,a set of method for motor temperature field simulation is established.The temperature measurement of permanent magnet of permanent magnet synchronous motor was designed by two temperature measurement methods:back EMF and temperature sensor.The back EMF method is deduced based on permanent magnetic materials with the characteristics of reversible demagnetization.A measuring coil is set on the stator slot of the motor,and the relation between the flux of the measuring coil and the temperature of the permanent magnet is deduced.The temperature of permanent magnet can be calculated by recording the flux value of coil.The temperature sensor method is designed using the slip ring as a signal transmission device.The accuracy and reliability of measurement of the contact temperature is greatly improved by the high performance of modular slip ring.Simulation and experimental results are presented to study the accuracy and error sources of the simulation and two temperature measurement methods.The advantages and disadvantages of the two temperature measurement methods are analyzed.As the methods of rotor temperature measurement,the application prospect is prospected.