无速度传感器矢量控制下高速电主轴动态性能分析

Dynamic Performance Analysis of High Speed Motorized Spindle under Speed Sensor-less Vector Control

为了研究高速电主轴的控制精度与主轴机械参数之间的动态关系,根据法拉第电磁感应定律建立高速电主轴的动态数学模型,并利用无速度传感器矢量控制逆变调速原理,将该模型的定子电流分解为励磁电流和转矩电流两个分量,组成两个独立的一阶线性子系统——磁链子系统和转矩子系统,实现励磁磁链和电磁转矩对各自参考值的全局渐进跟踪。试验结果表明,在无速度传感器矢量控制下,高速电主轴的励磁磁链受励磁电流的控制,且不受主轴负载和转速高低的影响,始终保持恒定;转矩电流控制高速电主轴的电磁转矩,与负载呈线性关系。有效控制励磁电流和转矩电流两个独立变量,不仅可以保证高速电主轴在负载状态下转差率小、转矩输出稳定性高的特点,而且当高速电主轴受到瞬间外力冲击时,其快速的转矩响应能力、动态速度跟随精度和抗挠动性等动态特性参数都可以通过控制励磁电流和转矩电流的精度实现。

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 modelis 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.