The Design And Simulation Research Of High-speed Motorized Spindle Vector Control System

The motorized spindle is the key component of the CNC machine tools, and its dynamic performance of the drive control determines the quality of the high-speed processing of the workpiece, so it is an important indicator of design and manufacturing of the high-speed CNC machine tool. The vector control is one of the main control method for high-speed motorized spindle, and it has been used in a wide range of applications by foreign countries. However, the high-speed spindle motor has high-order, strongly coupled and nonlinear characteristics, it is difficult to establish its precise mathematical model using mathematical method. In the actual processing of the application, the vector control system exist disturbance inevitably. Furthermore, It is difficult to overcome disturbances from model systems and external parameter variations for the traditional control, so it is necessary to introduce intelligent control into vector control to adjust the parameters of the controller according to the change of external disturbance.In order to improve the stability and reliability of motorized spindle when it is running. The simulation model of high-speed motorized spindle is built, and slip frequency vector controller is designed based on the basic principles of the slip frequency control and vector control, and then simulation studies is done through MATLAB/Simulink. The simulation results show that the controller using short time can make the speed of motorized spindle rose to the given speed smoothly, steadily and accurately, and stator flux trajectory of motorized spindle is approximately circular, so the motorized spindle can have less harmonic in voltage and current, thereby it can reduce the vibration and heat when motorized spindle is running. This controller for motorized spindle drive control system is feasible to satisfy the rapid responding requirements of speed control of motorized spindle using for processing, and the effectiveness of the motorized spindle model established in this simulation has been verified. The problem of motorized spindle in the control system modeling is solved through this simulation verification. However, through the stator flux trajectory we can see that motorized spindle has flux pulsation caused by PWM modulation in this control system, so motorized spindle has harmonic the inevitably. If the frequency of the PWM modulated wave is inappropriate choice, the motorized spindle also will overheat.A model of a speed and flux-closed-loop vector control system with a inner torque-closed loop is established, and fuzzy controller is used to adjust the speed. MATLAB is used for load simulation of high-speed segment of motorized spindle, then the simulation results show that, high-speed motorized spindle can be increased in to the high-speed segment using a short period of time, and it has strong anti-interference ability and excellent performance at the same time in the control system presented in this paper. Compared with slip frequency vector control, a flux regulator is added to the system. In the starting phase, the process of building of stator is relatively smooth, and the flux remains round. So the harmonics in voltage and current are less and motorized spindle has less vibration caused by harmonic. So the life of motorized spindle will be improved. The output torque of the motorized spindle will more smooth and stable than the motorized spindle controlled in slip frequency vector control system. Flux trajectory has fluctuations in slip frequency vector control system without the flux regulator when the motorized spindle begin to start, and that will lead torque ripple largely.Finally, a speed sensorless vector control system of motorized spindle is established. A model of a speed and flux-closed-loop vector control system with a inner torque-closed loop is also used, and the reference model reference adaptive system (MRAS) will be used for speed estimation. When the motorized spindle run stably, the estimated speed follow the actual speed closely, so it verify the feasibility of the speed estimator in the low-speed segment of motorized spindle speed estimation.