The Research Of AC Asynchronous Spindle Motor Control Technology

The asynchronous spindle motor is the core functional part of the high-speed machining machine.Its control performance directly affects the quality of the product processed by the entire CNC machine tool.Therefore,its control performance requirements are different from the general industrial drive control.It not only requires with higher speed accuracy and faster dynamic response,but also requires with high torque output and a wide speed range for stable operation.From the perspective of motor control technology,this dissertation investigates some methods to improve the spindle drive control system performance methods.Firstly,the background and significance of this research are introduced,the research status and development trend at home and abroad are analyzed based on the weak magnetic control method and flux linkage observer closely related to the control performance of the asynchronous spindle motor.On the basis of the above,the content of this project is established.Then the three-phase mathematical model of the asynchronous motor,the principle of coordinate transformation and the mathematical model in the orthogonal coordinate system after coordinate transformation are introduced.At last,the vector control of rotor field orientation and the principle of space voltage vector pulse width modulation are briefly introduced.In view of the problem of weak field weakening ability and the inability to guarantee maximum torque output for conventional weak magnetic control methods,the sum of the output values of voltage and speed loops is given as the excitation current to achieve the motor smooth transition between constant torque region and magnetic region.And according to the principle of optimal current distribution theory,applied to the current distribution strategy suitable for engineering implementation,an improved weak magnetic control method based on voltage and velocity loops is proposed.The method proposed in this paper can run at high speed,achieve large torque output and is easy to implement.In view of the problem of low accuracy of the flux linkage estimation,obvious disadvantages of parameter variation and sampling interference for the traditional flux linkage observer,this paper uses a closed-loop full-order observer to observe the flux linkage.And its feedback matrix are researched and analyzed according to modern control principles.Finally this dissertation designed a robust adaptive observer to estimate the flux linkage.The method applied can solve the problem of poor estimation accuracy and poor anti-interference ability of traditional observers.Finally,the effectiveness and feasibility of the weak magnetic control method and the robust adaptive flux linkage observer are verified by system simulation and experiments.And some key problems in the drive control system of the asynchronous spindle motor are well resolved to some extent,the performance of asynchronous spindle drive control system is improved.