Energy-efficient control of induction motors with high torque dynamics and transient skin effect

Servo drives are usually designed for time or energy optimal motion. However, this requires step change of torque reference leading to big transient skin effect and additional Joule losses or Joule heating in rotor bars. This is especially critical in dynamically controlled induction machines with deep rotor bars and small load cycles. Therefore, the skin effect is necessary to be taken into account at the optimization of the motion trajectory. Aiming at reducing the additional eddy current losses, this paper demonstrates how to determine an appropriate torque reference curve with less energy losses under different rotor bar forms and load cycles.