FREQUENCY-CONTROLLED INDUCTION MOTOR DRIVE Russian patent published in 1996 - IPC

FIELD: electrical engineering; induction motor drives using squirrel-cage induction motors. SUBSTANCE: frequency- controlled induction motor drive has induction motor 1, frequency changer, units 3, 4 controlling frequency changer frequency and voltage, adder 5, setting-point source 4. Introduced in electric drive are multiplying units 9, 10, 11, 14, 15, dividing units 12, 13, power and voltage differentiating units, speed sensor 8, functional transducer 16 implementing function η/(1-η), where η = P₂/P₁, P₂ is output power of induction motor, P₁ is full input power of induction motor. EFFECT: minimized total power depending on control frequency and motor shaft load which raises efficiency and simplifies design of drive due to elimination of motor flux and torque sensors as well as computing devices implementing flux changes with load and frequency. 1 dwg