Design Of Tubular Permanent Magnet Linear Motor And Calculation Of Eccentric Electromagnetic Force

The traditional rod pump oil production device has problems such as eccentric wear of the sucker rod and oil pipe,low oil production efficiency,and short pump inspection period,while the new reciprocating submersible direct drive system uses a tubular submersible permanent magnet linear motor to directly drive the plunger The pump can well solve the problem of eccentric wear of sucker rods and tubing,improve oil production efficiency,and can be used in low-production wells,deviated wells,directional wells and horizontal wells.In this paper,a tubular permanent magnet linear motor for submersible direct drive system is designed,and the influence of pole-slot coordination and power supply mode on the thrust density of the motor is studied,as well as the variation law of the eccentric lower end force and cogging force of the motor mover.The main research contents include the following parts:Firstly,the common topology structure of tubular permanent magnet linear motor,calculation method of air-gap magnetic field,cause and weakening method of thrust fluctuation,electromagnetic force generation mechanism and calculation method under eccentricity are reviewed,and the tubular oil submersible permanent magnet linear motor is clarified.research goals.Secondly,the design of the fractional slot tubular permanent magnet linear motor and the influence of the power supply method on the thrust density of the motor are studied.For the 21-slot 22-pole fractional-slot tubular permanent magnet linear motor,the design of the primary and secondary structures of the electrical pure iron and iron block type motor is studied;the double outer lead wire pie-shaped coil is studied to improve the full rate of the motor slot and reduce the copper consumption.Feasibility;comparatively analyze the thrust characteristics of the motor under the sinusoidal AC power supply and the brushless DC power supply.Then,the design of the tubular permanent magnet linear motor with concentrated full pitch winding and the influence of the power supply mode on the thrust density of the motor are studied.Study the design of 66-slot 22-pole integer-slot motors,study and compare the no-load positioning force and no-load air gap flux density of fractional-slot and concentrated full-pitch winding motors,and study the thrust of the motor under sinusoidal AC power supply and brushless DC power supply characteristic.Finally,the change law of the electromagnetic force of the tubular permanent magnet linear motor under the eccentricity of the mover is studied.The motor model under eccentricity is established by Ansoft software,the influence of eccentricity on the end force and cogging force of the motor is calculated,and the influence of eccentricity on the magnitude and fluctuation of the motor thrust is studied.