The Research Of Drive Control System Of Permanent Magnet Synchronous Motor For Numerically Controlled Machine Tools

Numerically Controlled(NC) machine tools which play an important role in the national economic development and enhancing the comprehensive national strength are the foundation of modern machinery industry. The development of servo drive control technology for NC machine tools are the key to improving and enhancing all kinds of the machine performances. And Permanent Magnet Synchronous Motor(PMSM) has been the development trends of modern AC servo drive control system because of the excellent performance it has, such as simple structure, small size, light weight, high efficiency, high power factor, low inertia, high overload capacity, fast response time, wide speed range and high reliability. Direct Torque Control(DTC) is a new technology of frequency conversion timing after Field Oriented Control(FOC), and it is also an AC speed control strategy of high static and dynamic. The DTC is a kind of algorithm of novel and simple ideas, small amount of calculation, torque response quickly, motor parameter independent and can control the torque and flux directly. At present, the direct torque control in PMSM for NC machine tools have become the research focus in the field of modern AC drive. This paper researches on the AC servo system of NC machine tools. And the strategy of DTC for PMSM was researched and implemented in this paper.According to the development and characteristics of DTC, emphatically expounds the working principle of the direct torque control for PMSM and designs the NC machine tools simulation model for PMSM direct torque speed regulation control system.It could satisfy the basic requirement of the speed control system of PMSM though the simulation of this build system in the paper.Considering the torque and flux ripple of the speed control system of the PMSM, a method of Active Disturbance Rejection Control(ADRC) is implemented in the AC servo system for NC machine tools in this paper. ADRC can estimate and compensate the outside disturbance change and inside parameters in time and has the advantages of fast response time, high accuracy, and strong robustness against load disturbance. Therefore, a kind of controller designed based on ADRC is applied for permanent magnet synchronous motor speed control system. Simulation and experiment results show that this method can improve the steady characteristics and anti load disturbance performances, the flux and the torque ripple also get certain inhibition.It will affect the control precision of the system using speed sensor for the AC servo system of NC machine tools. The application of an advanced speed sensorless control technology which would detect the relevant information of motor can avoid the inconvenience brought by installation of speed sensor and improve the reliability of NC machine tools. The speed sensorless control based on Model Reference Adaptive System(MRAS) technology for PMSM direct torque control system is presented in this paper. Then a new complex control strategy by introducing ADRC into MRAS is given. The result of simulation has indicated that the efficiency and accuracy can be evidently improved and dynamic characteristic can be greatly reformed for the speed regulating control system of the PMSM.