Design And Temperature Field Analysis Of Direct-drive Permanent Magnet Synchronous Motor For Submersible Screw Pump

With the oil extraction of our country,the use of the submersible screw pump oil extraction system has been more and more.The submersible screw pump oil extraction system has great advantages compared with other extraction equipment when working in the heave oil wells,sand wells,air wells.As the power plant of the submersible screw pump oil extraction system,submersible motor is very important for the efficient and stable operation of the submersible screw pump.The speed of traditional submersible motor is generally very high and need to equip the reducer when driving the submersible screw pump,which reduces the efficiency and stability of the oil extraction system.In this situation,it is very necessary to research and develop low-speed submersible motor.Firstly,this thesis introduces the structural characteristics of the drive submersible screw pump motor,and designs a prototype of 16-poles submersible permanent magnet synchronous motor.According to the design requirements of the motor,the main dimensions of the motor,the number of stator slots,the slot size,the winding arrangement and the size of the permanent magnet is designed.In order to decrease the leakage magnetic flux of tangential excitation,the air magnetic insulation structure is designed.In order to reduce the cogging torque of the motor,the non-uniform air gap structure is designed.In order to test the working performance of the designed motor,the electromagnetic calculation program of the motor is designed by MATLAB language.Then the calculation method of the leakage magnetic flux coefficient is analyzed in detail,and the suitable width of magnetic insolation bridge is selected.As a comparison,the Maxwell simulation software was used to calculate the electromagnetic field of the motor at no-load and load.The back electromotive force,the air gap magnetic flux density and the cogging torque of the motor are analyzed at no-load when using the uniform air gap and the non-uniform air gap structure.Then the performance of the designed motor is analyzed at different loads.Considering the difficulty of heat emission and the closed working environment of submersible motor,this thesis has carried on the finite element simulation analysis of the temperature field of the designed motor.The loss of each part of the motor is calculated when oil well temperature is 90?.The equivalent heat dissipation coefficient of each surface of the motor is calculated by the knowledge of fluid mechanics,and a threedimensional simulation model of the pitch range is established.Then the temperature field of the motor is calculated.Through the above simulation calculation,it proves the rationality of the designed motor and can meet the working environment requirements of the submersible screw pump motor.