All digital high performance controller for spindle motor in CNC machine tool

This paper presents the development of an all digital high performance controller for induction motors, which is used in the CNC machine tool. The authors apply the nonlinear controller and the PI controller to the spindle motor under vector control to obtain the desired performance. In the PWM converter control, they use a control scheme consisting of a feedforward controller, a PI controller, a load current observer and a PLL-type phase angle estimator of the three-phase source voltage. Experimental results show good performance of the proposed controller in controlling the spindle motor in CNC machine tools