CONTROLLER FOR INDUCTION MOTOR

摘要

PURPOSE:To maintain a constant torque by providing means for correcting a voltage, proportional to an inverter frequency, according to the inner impedance angle of an induction motor. CONSTITUTION:Rotational frequency FR of motor and a slip frequency FS are added in an adder 1401 to produce an inverter frequency FINV. An arithmetic unit 1403 receives the inverter frequency FINV and outputs an electrical angle omega. A slip rate operating unit 1402 receives the slip frequency FS and the inverter frequency FINV and outputs a slip rate S. The slip rate S is employed in the operation of a secondary impedance Z'2. An impedance angle operating unit 1404 receives the slip rate S and the electrical angle omega and outputs an impedance angle phi. A coefficient operating unit 1405 determines the ratio between sinphi0 and sinphi at a rating point and outputs a coefficient K1.