Research And Design Of Mine High Performance And Low Cost Permanent Magnet Motor For Belt Conveyor

At present,the asynchronous motor and the reduction gear drive together are often used on the coal mine production.The disadvantages of this method are large loss,low efficiency,and large power consumption.Now,the society's demand for high-efficiency and energysaving products has increased.The low-speed and large-torque permanent magnet synchronous motor(PMSM)can abandon the reducer coupler and other equipment to achieve direct drive of load.The efficiency of it is much higher than that of asynchronous motors during light-load operation.And it has lower power consumption and higher effciency.With the continuous development of PMSM,small size,light weight,high efficiency,good dynamic performance,energy saving and environmental protection have become the development goals of permanent magnet motors,and cost-effective motors have gradually become the first choice for drive equipment.A low-speed high-torque PMSM will be designed in this article,with a rated power of 250 k W and a speed of 82.5r/min from the perspective of economy..The main work of this paper is as follows:First,the factors affecting and the effective cost of permanent magnet motors are analyzed in this article.Taked a 40-pole 48-slot motor as an example: by calculating the torque density of the motor in different magnetic circuit structure and the output power of the motor in different stator slots,it is concluded that for high power low-speed high-torque PMSM,built-in radial rotor structure and rectangular slot can effectively improve motor performance and reduce the effective cost of motor.Analyze the effect of stator split ratio and slenderness ratio on the performance of low speed and high torque PMSM.Finally,by comparing the design schemes of twelve motors,the conclusion that the low-speed and high-torque motor with flat shape has better performance and lower cost is obtained.Then,according to the requirements of the subject,a belt-driven low-speed high-torque PMSM was designed,with a rated power of 250 k W and a speed of 82.5r/min.Combining the use environment and transmission characteristics of the motor,starting from the main dimensions,stator punching,armature winding,rotor structure,permanent magnet size design,etc.,the design features of the stator and rotor structure of the low-speed high-torque PMSM are introduced in detail.Combined with the conventional motor design method,the design parameters of PMSM are obtained by way of calculation program.Use the finite element analysis model to simulate the magnetic field distribution of the motor under no-load and load conditions.Calculate the motor output torque and the loss value of each part,and compare with the road calculation program to verify the rationality of the design scheme.Finally,in view of the difficulty in heat dissipation of low-speed and large-torque PMSM in the mine,the motor water cooling system is analyzed.Compare the cooling effects of the three water-cooled structures,select the appropriate waterway structure,and further optimize the design.Whether the water-cooled structure meets the temperature rise requirements of the motor through temperature field simulation.According to the above design results,the prototype is completed and the basic experimental test is carried out.