Study On Correlative Problem Of Direct Drive BLDCM For Screw Pump System

Screw pump petroleum production is a new style mechanical petroleum production whose applied range is gradual expanded, and applied prospect is very extensive. But the conventional screw pump driving system which generally adopts induction motor assorted speed reducer has low efficiency and difficult speed regulation, which already can't meet the need of current phase. Against the status, PM brushless torque motor to drive screw pump directly was adopted by the paper, and the correlative problem was studied.Loss and temperature rise of motor was studied. Through theory analysis to motor loss, a mathematic model of motor loss was established, and the loss of motor was calculated by finite-element method. On the base of calculation of motor loss, the model of 3D transient temperature field for motor was established and simulated. For the specialty of PM brushless torque motor loss, the mostly parameter affecting PM brushless torque motor was pointed out, and the influences to the motor loss for different number of stator slots or different number of rotor pole pairs were analyzed.The problems of screw pump reversal while needing stops was studied. A mathematic model of screw pumping rod was established, and the way of dynamic braking was adopted to make the system stops safely and quickly, then the way was certified by simulation.The temperature rise test and mechanical character test were done. The performance of motor was tested, and the test result was compared with simulation and calculation result to certify the accuracy of simulation.