ALTERNATING CURRENT ELECTRIC DRIVE Russian patent published in 2014 - IPC H02P27/06 

FIELD: electricity.

SUBSTANCE: invention is related to electric engineering, in particular, to variable alternating current electric drives. An AC electric drive comprising an induction motor with a phase rotor and an inverter with PWM current controller, two stator current sensors, a speed sensor set on the motor's shaft, a calculating unit for the setup of the motor torque, a calculating unit for the setup of stator current, a setup unit for stator phase currents, a setup unit for stator field rotation speed, is equipped by a correction unit for the motor torque setup including additional rotor current sensors and a unit for calculation operations which generates a correction signal for the motor torque setup in the function of the parameter defined in simpler way - tangent of angle between the vectors of stator currents and of magnetising current calculated on the basis of the measured phase currents of the motor stator and rotor. Inverter generates stator phase currents with amplitude and frequency required to generate the specified torque value provided that stator current consumption from the network is minimised. The electric drive is fitted by the correction system with actual measured variables thus simplifying the algorithm for correction signal calculation and bating requirements to the process controller.

EFFECT: reduction of stator current that ensures the specified motor torque, simplification and improved operability of the device.

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