Design Of Submersible Permanent Magnet Linear Motor Of Moving Sub Position Self-detecting

With the increasing demand for petroleum energy in various industries,most oilfield exploitation has entered the middle and late stages.The reciprocating submersible permanent magnet linear electric pump as a new type of oil mining equipment solves the problem of partial wear of the rods and improves oil recovery efficiency.It is suitable for "three low" reservoirs and can be applied to low-production wells,inclined wells,directional wells,horizontal wells and heavy oil wells.The tubular permanent magnet linear motor is the core component of the submersible direct drive system.It can directly drive the oil well plunger pump to reciprocate to achieve the purpose of lifting the liquid from the oil well.In this paper,the electromagnetic design,parameter calculation,thrust performance optimization,and relative position detection of the mover are performed on the tubular permanent magnet linear motor used in the reciprocating submersible permanent magnet linear electric pump.The main research contents include the following parts:Firstly,this article introduces the basic structure and working principle of tubular permanent magnet linear motor and summarizes the research overview of tubular permanent magnet linear motor at home and abroad.And this article consulted the related literatures on the design and control of reciprocating submersible permanent magnet linear motors and the method of weakening the thrust fluctuations of permanent magnet linear motors.Secondly,this article aims at the particularity of the application environment of reciprocating submersible permanent magnet linear motor.According to the design theory of permanent magnet linear motor and the method of calculating electromagnetic parameters,this article aims at the electromagnetic design and parameter performance calculation of tubular permanent magnet linear motor and determines the main structural parameters of the reciprocating submersible permanent magnet linear motor.Then,taking 9-slot 8-pole and 9-slot 10-pole fractional slot tubular permanent magnet linear motors as examples,the influences of primary tooth width and axial length of permanent magnet on the thrust performance of the motors are analyzed,so as to determine a better structure and optimize the thrust performance of the motors.The electromagnetic performance and permanent magnet consumption of two kinds of tubular permanent magnet linear motorswith the same number of poles in the primary armature are studied.The slotting effect of tubular permanent magnet linear motor is analyzed,and a method of evenly dividing the magnetic pole under each pole into two segments with the same polarity is proposed,which effectively reduces the slotting force of tubular permanent magnet linear motor.Finally,this thesis introduces the main structure and working principle.To solve the problem of reciprocating submersible permanent magnet linear motor in the harsh environment down hole,the secondary structure of a new cylindrical permanent magnet linear motor with non-magnetically conductive ends is proposed.Due to the change of the magnetic circuit of magnetic conductivity,resulting in asymmetric three phase current,tubular permanent magnet linear motor can realize the submersible electric motor position detection by detecting the output current waveform and the winding inductance and timely changing phases to achieve the reciprocating movement of the submersible motor.Using ansoft software to design the motor modeling simulation.The results verify the correctness and practicability of the theory of reciprocating submersible permanent magnet linear motor.