High performance speed servo system considering voltage saturation of vector controlled induction motor

Generally, a speed servo system of vector-controlled induction motor has a limitation of motor voltage and motor current. When the speed servo system has a large torque reference, the output of its PI controller is often saturated. In this case, the conventional servo system stops the integral calculation of its PI controller. However, this system often has a large overshoot and/or an oscillated response caused by both a windup phenomenon and phase error on vector control condition. This paper proposes a new speed servo system considering voltage saturation for vector-controlled induction motor. The proposed control method compensates the phase error on vector control condition quickly, and always keeps the vector control condition. The experimental results show that the proposed system well regulates a motor speed and a motor secondary magnetic flux for a large torque reference without a windup phenomenon.