Research On Control System Of BLDCM For The Drive Of Well Logging Piston Pump

In this paper, taking into account the oilfield logging pump used in the actualworking environment of the brushless DC motor, For the power supply voltageripple caused by the brushless DC motor speed ripple and speed ripple due to loadfluctuations caused by problems. Proposed PLL control with conventional PIDalgorithm control strategy combining inhibition. Research and was designed for thewell high temperature, high pressure environment of the brushless DC motor controlsystem, Design of Motor constant speed and constant power control of twofunctions.For fluctuation of the motor speed by the power supply voltage ripple, abrushless DC motor control system simulation model are builded, summed upsummarize the variation of the rectified DC power supply voltage ripple; Analysisof the variation of the voltage ripple caused by the main reason for the motor speedripple and speed ripple, and take a closed-loop control method to be suppressed.Taking into account the mining pump brushless DC motor load is alwayschanged with the oil viscosity different, in order to ensure the stability and controlaccuracy of motor speed in the course of their work under the well, this paperpresents a control algorithm combining PLL control and traditional PID control.This control algorithm uses the advantages of good stability of the phase-lockedloop control, high control precision, fast response, again with the traditional PIDalgorithm to compensate for the PLL control can not enter the locked state in thelow speed situation. By combining these two control strategies, the inhibition of theload fluctuations in the case of brushless DC motor speed ripple, and then come truethe constant motor speed control function; Another feature of the brushed DC motorto run in a state of constant power, its implementation is the use of the PID controlalgorithm to control the DC bus.In order to achieve the two control functions of the Constant Speed and andconstant power piston pump to use the brushless DC motor control system, designedof the hardware part of the DSP2812is the main control circuit, DC bus currentsensing circuit, the rotor position detection circuit, and overcurrent protectioncircuit control system, by the DSP software to complete the acquisition of thebrushless DC motor rotor position signal, commutation logic processing, theproduction of the PWM signal, motor feedback current signal sampling, control andconstant power speed phase-locked loop and PID combination of traditional PIDcontrol algorithm implementation, soft start the motor and the system with a PChost computer communicates through the SCI. The last by the experimental subject brushless DC motor control system wasverified the motor speed pulsation has been a very good suppression, Constantrotational speed of the system and constant power requirements of the two controlfunctions.