The induction servo motor used in this drive system is a three-phase Y-connected four-pole 800W 60Hz 130Vl5.6A type. Moreover, the drive system is a ramp comparison current-controlled pulse-width-modulated (PWM) voltage source inverter (PSI) . The current-controlled VSI is implemented by isolated gate bipolar transistor (IGBT) switching components with a switching frequency of 5kHz. For the position control system, the braking machine is driven by a current source drive to provide braking torque . An inertia varying mechanism is coupled to the rotor of the induction servo motor