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针对电主轴在高速切削过程中动态精度控制不稳定问题,提出一种依据电主轴定子输入端电压、电流值来预测主轴输出转矩和转速的方法。该方法根据无速度传感器矢量控制原理,结合主轴电阻、电感等电磁参数,以转子磁链幅值和相位角为桥梁,建立电主轴定子输入端的三相电压、电流与转子输出端转速、转矩之间的数学模型,从而构建无速度传感器矢量控制下速度外环和电流内环的双闭环控制系统。通过该双闭环系统,将电主轴在切削过程中定子输入端的三相电压、电流,转换成两相旋转坐标系下的电压、电流。并在此基础上,进一步将电流环分解为磁链环和转矩环两个独立控制的子系统,以分别控制转子磁链和电磁转矩,从而可以通过观测磁链环的励磁电流和转矩环转矩电流的变化趋势,判断主轴输出端转矩、转速的稳定性。最后通过切削实验,验证了上述方法的可行性。
Aiming at the instability of dynamic precision control of spindle in high speed cutting process, a method of predicting spindle output torque and rotating speed based on the voltage and current value of stator spindle input is proposed. According to the principle of speed sensorless vector control and the electromagnetic parameters of spindle resistance and inductance, the method takes the rotor flux linkage amplitude and phase angle as the bridge to establish the three-phase voltage, current and rotor output speed, torque To build a double closed-loop control system of speed outer loop and current inner loop under the speed sensorless vector control. Through the double closed-loop system, the three-phase voltage and current of the stator input end during the cutting process of the electric spindle are converted into the voltage and the current in the two-phase rotating coordinate system. On this basis, the current loop is further decomposed into two independently controlled subsystems of flux linkage and torque loop to control the rotor flux and torque, respectively, so that by observing the excitation current and flux of the flux linkage Moment ring torque current trends to determine the spindle output torque, speed stability. Finally, cutting experiments verify the feasibility of the above method.