The Research On Coordinated Control Technology Of AC Variable Frequency Drive Deep Drilling Winch

The winch of extra deep shaft rig is driven by multiple high power motors that paralleled, which guarantees drilling's power requirement; and because the structure of winch multiple-motor drive system is symmetrical, therefore the problems such as vibration of drum shaft and unbalance of stress are obviously reduced. But, because some reasons of manufacturing, even if the motors have same model and rating, there still exist difference on mechanical properties between them. Therefore, in the process of driving winch roller, the motor group appears some situation like out-of-step and load unbalanced. Those situation has affected system's transmission efficiency, and caused unnecessarily energy wastage. If those situation exist over a long time, it will not only cause damage to the motors, but also affect the process of drilling.In view of the above question, this paper combined actual working condition, and then discussed,studied coordination control technique of winch multi-motor.Firstly, The paper analyzed the structure and principle of dual-motor drive system, so that to find out the reason of load imbalanced against motor group which connected by the same axle in the process of compound transmission, and select the mode of master-slave synchronization to eliminate the power difference which existed in multi-motor; then the paper analysised vector control of AC asynchronous motor,and established the mathematical model of motors as well as transmission system, and designed proposal of closed-loop transmission system which includes the rotation speed-power ring; Finally, under the MATLAB/Simulink environment, it has implemented simulation to the transmission system of multi-motor. It used the fuzzy-PID control algorithm to accomplish simulation in paper, and introduce fuzzy control strategy in detail, also designed the core unit—fuzzy PID controller; In the process of simulation, it has considered steady work and subjected to load shock such two kinds of situations, and then carried on analysis to control response for those situation. The simulation results show that the design of this thesis can get a good control effect.