SLIP-RING MOTOR CONTROL PROCESS Russian patent published in 1997 - IPC

FIELD: general-purpose electric drives. SUBSTANCE: induction motor control process involves power supply of stator winding from inverter. Series-connected in rotor circuit are inverter, uncontrolled and controlled rectifiers. Current measured at inverter input is compared with desired value and comparison results are used to regulate voltage across controlled rectifier output to reduce error between measured and desired currents at inverter input. Speed is controlled by varying voltage frequency at inverter input. EFFECT: reduced loss, improved reliability and torque regulation stability. 2 dwg