Temperature rise is a key performance parameter of brushless motor, different thermal resistance level of the motor requirements for temperature rise has some differences; temperature rise and temperature is positively correlated, but the temperature of different parts of the brushless motor is different, but the distribution is very regular. Today based on the temperature distribution of different ventilation structure motor.
In the calculation of the temperature rise of brushless motor, the temperature rise of winding and core is mainly calculated. These components are not only heat conducting media, but also distributed heat sources. Generally speaking, their temperatures show a certain curve distribution pattern in space, and there is a difference between high temperature rise and average temperature rise. Although the heat generation limit of each part of the motor should be based on the high temperature rise, in the calculation, from the overall view, usually only the average temperature rise of the heat generating parts of the motor can be calculated; there is a certain regular relationship between the average temperature rise and the high temperature rise, therefore, the average temperature rise can be used to measure the heat generation of the motor.
1、The axial temperature distribution of the stator winding of symmetrical radial ventilation motor, the air volume through each radial ventilation channel is basically the same, and the high temperature in the middle winding and core of the motor both occur.
2, is a kind of asymmetric ventilation system at both ends, in the case of higher temperatures, from the middle of the symmetric ventilation system situation movement to the hot air escapes from the motor outlet.
3, the temperature of the surface-cooled closed stator winding is distributed along the axial direction, and the losses in the stator winding are mainly dissipated through the iron core and frame. The heat dissipation condition at the end of the winding is poor, so part of the heat lost at the end is also transferred through the slot and dissipated through the core. Therefore, the temperature distribution of the stator winding is high at both ends and low in the middle.
4. The temperature distribution of the excitation winding is mainly dissipated from the surface because its height is much larger than its thickness. This coil usually has different heat dissipation on the inner and outer surfaces of the coil, so the temperature distribution is asymmetric.
In order to solve the influence of the temperature characteristics of the material on the loss during the calculation of the permanent magnet brushless motor, the corresponding temperature rise analysis method is used to realize the temperature rise calculation of the permanent magnet brushless motor.