The Research Of High Speed Asynchronous Spindle Motor Control System

The high speed drive system for induction motor has been widely used in machine tool spindle, traction, electric vehicles and other fields.It plays an important role in automation equipment. Induction motor used in spindle driver systems of machine tool which was required out a wide speed range,high torque,high dynamic performance. Based on the analysis of relevant literatures in domestic and overseas, proposes a rotor field oriented weak magnetic control of high performance asynchronous motor drive control system based on the strategy of building.Spindle driving motor for CNC machine tool usually adopts asynchronous motor。 The rotor flux-oriented vector control is a basic candidate for wide speed range control because decoupling control between torque and flux can be realized easily.Firstly, rotor flux-oriented vector control for asynchronous motor are analyzed in detail.and an related mathematical model are constructed.Based on this method, several key problems need to be solved in vector control are analyzed, such as coordinate transformation,The design of the rotor flux-observer, space voltage vector pulse width modulation algorithm SVPWM is introduced.Based on this method, the two key problems of high-speed drive system are presented as the current decoupling control algorithm and maximize the output torque of the weak magnetic control algorithm.In coordinate transformation, decoupling between torque and flux has not been achieved completely, a coupling effect generates between d axis current loop and q axis current loop.therefore, Firstly, analysising and designing current control scheme of synchronous PI regulator, then In the different coupling factors, current decoupling control theory is analyzed, and designing the PI controller with feedforward decoupling, but it is sensitive to the motor parameters, which was led to reduce in decoupling effect in high speed region parameter changes, and therefore it was not suitable for use, finally a PI controller with anti-windup control is implemented by complex vector method,which was replace the traditional synchronous PI current regulator, which can eliminate the negative influence of coupling voltage and current regulator, compared with the feed-forward scheme, it improves the robustness of the system parameters of the motor, by which the tracking control performance of the current loop is improved greatly in the high frequency region.In a torque-controlled spindle motor drive, the maximum output torque and output power depends on the inverter current rating and the maximum voltage that the inverter can supply to the machine. To operate the machine at very high speed as required in many applications, field-weakening strategy should be adopted, but the available torque is reduced. A special control strategy, which considers current and voltage limitations, should be implemented so that a maximum torque can be obtained in the whole speed range. Based on the relevant documented, a suitable speed control was adopted in the field-weakening region, the operation range of motor can be extended,and motor maximum torque output capacity was improved in weak magnetic region.Finally, the high speed drive system for induction motor based on rotor flux orientation has been fully implemented and the validities of the proposed key control algorithm have been verified.Experimental investigations show that the proposed strategies provide a substantial improvement of the performance for asynchronous spindle motor in high speed region.