System for estimating rotor resistance of an induction motor

A system for estimating a rotor resistance of an induction motor comprising:

• an equivalent torque curve generation unit configured to generate an equivalent torque curve based on output torques of the induction motor determined according to a stator current command;
• a minimum current operation point determination unit configured to determine a minimum current operation point of the equivalent torque curve;
• an equivalent current phase variable control unit configured to variably control a rotor resistance of the induction motor in a state in which the stator current command of the minimum current operation point is applied to the induction motor;
• an output torque detection unit configured to detect the output torque of the induction motor when the equivalent current phase variable control unit variably controls the rotor resistance;
• and
• a rotor resistance determination unit configured to:
• determine a maximum torque among the output torques detected by the output torque detection unit, and
• determine the rotor resistance when the maximum torque is generated as an actual rotor resistance of the induction motor.