抄録
An induction motor is one of the suitable motors for the electric vehicles. The induction motor used in the electric vehicle has been generally controlled based on the vector control method to obtain well dynamic torque response. The field forming current value is kept a constant to keep the constant flux level in the conventional vector control system, but it has disadvantage that the proportion of core loss is increase at the light load torque region. To solve this problem, the efficiency maximizing control method of the vector controlled induction motor has been presented. This paper proposes a simple solution which maximize the motor efficiency under any load conditions, and presents a simple efficiency maximizing control system. The usefulness of this system is demonstrated through the simulations and experiments that compare its efficiency characteristics with conventional vector control system. In this system, the secondary flux level is varied to reduce the core loss. This paper also includes the secondary flux control method to improve the delay in the output torque response when the secondary flux level is varied.
