ALTERNATING CURRENT ELECTRIC DRIVE Russian patent published in 2012 - IPC H02P27/06 H02P27/08 

FIELD: electricity.

SUBSTANCE: motor torque setting corrector is introduced into alternating current drive and is used for formation of stator current vector by forming instantaneous phase values of stator current, which amplitude and frequency depend on setting and correction signals. Maintenance of optimal level for stator current amplitude and frequency provides optimal angle φ₀ between vectors of stator current and rotor magnetic linkage equal to 45° and minimises consumption of stator current. Maintenance of optimal level φ₀ is ensured by closed loop of angle control; measurement of angle φ₀ is done by measurement of phase shift angle between instantaneous values of stator current and calculated values of rotor magnetic linkage. Invertor generates rotor phase currents with amplitude and frequency required to generate torque setting provided that current consumption by stator is minimised and magnetic circuit is used completely. Magnetic circuit operates with real three-phase system of coordinates that excludes coordinates conversion which complicate calculation and set strict requirements to controller.

EFFECT: design simplification and improvement of dynamic behaviour.

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