Design Of Direct-drive Permanent Magnet Motor And Cooling System

Belt conveyor adopts low speed high torque direct drive permanent magnet motor to replace the traditional induction motor and speed reducer in coal transportation industry. This structure is the direction of future development that improves the efficiency, reduces the volume of the system and the noise. In order to improve the utilization rate of materials, reduce the production cost of the motor, the motor usually has high electromagnetic load. High electromagnetic load will increase the heating of the motor, affect the motor performance. Reasonable design of cooling system can reduce the temperature rise of the motor, while the accurate calculation of temperature rise can guide the rational design of motor’s cooling system.The electromagnetic field,fluid field and temperature field of water cooled PMSM are studied in this article, main contents are as follows:First of all, reasonable electromagnetic scheme of the motor was designed. The mine permanent magnet direct drive motor requires high torque density, and most of the time operates at light load. The main dimensions and magnetic circuit structure was determined according to the requirements and characteristics of the motor;Through the comparison of different pole/slot combination performance selected 3 kind of pole/slot combination that have higher torque density. According to the actual load rate of motor selected high efficiency pole /slot combination.Secondly, the cooling system is designed according to the temperature fields calculation of motor.The cooling system type and parameter was determined.The prototype was tested to verify accuracy of the relevant calculation methods and results.according to the calculation result and experimental result,we can mprove the electromagnetic property.Then,improved the design of motor,improved motor’s torque density greatly, compared the improved scheme and the sample machine speed performance and calculated the electromagnetic parameters.We find that PM and rator fever seriously. The relationship between the cooling water flow rate and temperature rise was deduced with the analytical formula, a relation curve was made, and the curve inflection point was calculated. The curve distribution was validated by the finite volume method and test. In addition, under the same water flow rate, the driving loss under different channel conditions was studied, the relationship between the number of the channel and the temperature rise of the motor,the reasonable cooling channel of the motor were given.Finally, the rotor and permanent magnet heating problem were solved,the factors that influent the intensity of convective heat transfer was analysised.The heating problem was solved by add Cooling wind thorn and ventilatting duct.Studied the influence of the heat dissipation effect with different wind thorn, temperature of PM increase with the length of the wind thorn, drease first and decrease then with the width of the wind thorn.After add the axis direction and radius direction ventilatting duct,The temperature of PM drease with increase of the number of radius direction ventilatting ducts and the CSA of radius direction ventilatting ducts.