Dynamic performance analysis of high speed motorized spindle under speed sensor-less vector control

To study the dynamic relationship between the control precision and mechanical parameters of high speed motorized spindle, a dynamic mathematical model is established on the basis of Faraday law of electromagnetic induction. According to the inverter speed principle of speed sensor-less vector control, the stator current of this model is decomposed into excitation current and torque current. Those currents formed two independent first-order linear subsystems-magnetic chain subsystem and electromagnetic torque subsystem, so as to realize the global asymptotic tracking of excitation flux and electromagnetic torque on their reference signals. Test results show that, under the speed sensor-less vector control, excitation flux is determined by the excitation current of the high speed motorized spindle; it keeps constant and has nothing to do with both spindle load and speed; the torque current controls the electromagnetic torque of the spindle, showing a linear relationship with load. At the same time, effective control of excitation current and torque current can guarantee the small slip ratio and high stability of torque output. Also when high speed motorized spindle is impacted by an instant external force, the dynamic characteristic parameters such as rapid response capability of the torque, dynamic speed accuracy to follow, and anti-torsion mobility, can be realized by controlling the precision of the excitation current and torque current. © 2010 Journal of Mechanical Engineering.