Research On Application Of Internal Model Control Of Permanent Magnet Direct Drive Drilling Motor

At present,oil drilling equipment still adopts the drive mode of asynchronous motor acceleration and deceleration.Due to mechanical reasons such as reducer gears,the transmission efficiency of the system is reduced,and the cost of drilling is increased.Permanent magnet synchronous motors have a higher power factor than asynchronous motors of the same capacity.This paper combines the characteristics of low speed and large torque of drilling equipment and its requirement for direct drive of the motor,and it takes surface-mounted permanent magnet synchronous motor as the research object,and it studies its vector control system and internal model control technology.The existence of the coupling potential of the permanent magnet synchronous motor makes the accuracy of the shaft current control decrease,and then affects the control performance of the speed and torque.The vector control strategy of the permanent magnet synchronous motor based on internal model decoupling is introduced to decouple the d-q current.Simulation analysis shows that the decoupled control of the internal model can effectively reduce the coupling of the d-q axis current and improve the dynamic response of the current.The decoupling control of the internal model improves the torque control accuracy and achieves high-performance torque control.In view of the fact that the internal model control has only one adjustable parameter ?,various disturbances encountered in the drilling process restrict the further improvement of the system performance and affect the application of internal model control in drilling engineering.Aiming at this problem,a two-degree-of-freedom internal model controller is designed.The feedback controller is used to compensate for the deviation caused by the disturbance and model error.The anti-jamming performance of the controller is adjusted by adjusting the parameter ?₁;feedforward control the device mainly completes the tracking of a given signal,and adjusts the tracking of the controller by adjusting the parameter ?₂ so as to achieve independent adjustment of the anti-interference performance and tracking performance of the control system.The simulation and comparison and verification show that the performance of the two-degreeof-freedom internal model controller is better than that of the internal model controller when the motor starts without load,the load disturbance and the motor parameters change.For the disturbance of the load caused by the complex formation and drilling tool elastic energy storage during drilling,the two-degrees of freedom internal model control is applied to the top drive motor control system,the internal model decoupling control is used to improve the system's anti-jamming performance,and the feed forward control is used to load Torque fluctuations caused by changes are compensated to improve the tracking of the top drive motor control system.Through the performance test of two-degree-of-freedom internal model control system at the wellsite,the results show that the designed control system can follow the changing rules of the speed and torque,and reduce the fluctuation of the speed and torque of the topdrive motor in a short time.It has a good inhibition effect on drilling tool vibration caused by drilling conditions.