Design And Loss Analysis Of High-speed Permanent Magnet Synchronous Motor For Air Compressor

Air compressor is the main power source of modern industrial manufacturing.The combined structure of traditional asynchronous motor connected gearbox is often inefficient,and it wastes a lot of energy.Using high-speed permanent magnet synchronous motor to drive air compressor can not only give full play to the advantages of high efficiency of permanent magnet motor,but also eliminate the inherent defects such as energy loss and a large amount of audible noise brought by variable speed device.It is an effective scheme to improve the overall efficiency of air compressor system.However,there are many difficulties to overcome in this scheme,not only to make the performance of the designed high-efficiency permanent magnet motor meet the requirements within limited installation space,but also ensure the stability and heat dissipation of the motor under high-speed operation.In view of the above technical difficulties,this paper is aimed at designing a high-speed permanent magnet synchronous motor for air compressor with power of 100 k W,speed of 15000r/min and efficiency higher than 96%.Then a reasonable cooling system is designed to ensure the safe operation of the motor.The specific research contents of this paper are as follows:Firstly,the solutions to enhance the efficiency of high-speed permanent magnet motor is deeply studied in this paper.The effects of different magnetization methods,combined magnetic pole array,opening angle of built-in permanent magnet and inclined pole form of permanent magnet on iron loss of high-speed motor are explored.The effects of permanent magnet sectional structure and sheath material and thickness on eddy current loss of high-speed motor are explored.Aiming at the problem that it is difficult to accurately calculate the wind friction loss between the sheath surface and the air gap under the high-speed operation of high-speed motor,the wind friction loss is accurately modeled and simulated by using fluent fluid field calculation software,which paves the way for the design of high-efficiency motor.Secondly,the high efficiency high speed permanent magnet synchronous motor is designed comprehensively according to the electromagnetic performance indexes required.The main dimensions of the motor are preliminarily calculated,and the research of various kinds of loss is fully applied to the design of motor.The magnetic pole structure of the motor is determined by comparing the performance of the optimized rotor pole with the surface mounted pole and the built-in pole.Then the winding form of the motor is designed,and the performance of the motor with different stator inner diameter,air gap length and pole slot is compared.The overall electromagnetic design scheme of the motor is determined with the considering of efficiency and cost.The electromagnetic simulation of the designed motor is carried out under no-load and load conditions,the results meet the original design requirements.Finally,in allusion to the problems of small volume,high frequency and poor heat dissipation conditions of high-speed permanent magnet motor,three water channel forms of spiral,Z-shaped and ring multi parallel are designed.Then the losses of the motor are loaded into fluent as the heat source for fluid structure coupling simulation.It is determined that the ring multi parallel is more suitable and the cooling effect is better.According to the preliminarily selected water channel form,the influence of water channel velocity and section shape on motor cooling effect is studied,and finally the design of motor cooling is completed.