EXCITATION CURRENT CONTROL FOR INDUCTION MOTOR DRIVE USING LOAD COMMUTATED INVERTER CIRCUIT

摘要

A system for controlling the operation of an alternating current induction motor having windings supplied by electrical power from the polyphase alternating current source includes a load commutated inverter circuit which is connected between the power source and the induction motor for furnishing electrical power to the motor. Controllers responsive to a command signal and a feedback signal indicative of motor operating parameters control the operation of said load commutated inverter circuit. There is further provided a fixed capacitor circuit connected between the windings of the motor for supplying reactive volt amperes (VARs) to said load commutated inverter circuit and said motor. Finally, there is provided a variable VAR generator connected between the motor windings for supplying VARs to said load commutated inverter circuit and said motor in response to the output of a third feedback control path which is also responsive to a command signal and prescribed operating parameter(s) of said load and or said commutated inverter.