Electromagnetic Design On Brushless DC Motor In Direct Driving Pumping Simulation System

This paper reforms the traditional beam pumping unit and puts forward a exterior rotor brushless motor structure which can directly driven the pumping unit, saving such connecting units as reducer and four links. The exterior rotor brushless motor realizes sucker rod round-trip movement by controlling positive and negative operation. This structure can thoroughly change the problems of low efficiency, low power factor, high maintenance expenses, unable to free adjustment stroke that traditional pumping high-speed drive and multi-stage transmission brings.Through the research on the feasibility of straight pumping unit simulation system and realization of the exterior rotor brushless motor directly driven pumping unit on oilfield, This paper analyzes and designs the brushless dc motor of straight drive pumping simulation system. The main research results are as follows:(1) According to the design index of straight drive pumping simulation system brushless dc motor analysis the motor magnetic characteristics and reasonably select the motor structure and estimated parameters. Using equivalent magnetic circuit method in the permanent magnet motor get design parameters of the motor, and compile electromagnetic program in MATLAB;(2) In-depth analysis the motor magnetic field distribution and study the motor armature structure and armature reaction on the distribution of magnetic field by using ANS YS finite element software establishing a pair of poles model of direct drive pumping simulation system for brushless dc motor. Combined with finite element theory and motor running characteristics obtain the two-dimensional finite element calculation of motor model in static, and then optimize the motor design parameters;(3) Through comparing the torque waveform between the stator with slides and stator without slides obtains the torque calculation in finite element when the stator in slides structure, and proof the conclusion that slides can effectively reduce brushless dc motor torque fluctuations;(4) Combining with equivalent magnetic circuit method and finite element calculation method, get the electromagnetic design scheme in straight drive pumping simulation system of brushless dc motor, and processes the motor.