REACTIVE-POWER CORRECTION DEVICE Russian patent published in 2002 - IPC

FIELD: reactive power correction; electrified ac consist. SUBSTANCE: device functions to correct reactive power at sine-wave and distorted- wave voltage and current and under various operating conditions of locomotive by improving input current waveform and also by correcting reactive component of input current under conditions other than those rated. Device has load, reactive-power source incorporating series-connected inductance coil, capacitor, and two thyristors connected in parallel opposition, supply mains current and voltage transducer incorporating potential transformer and current transformer, sync pulse unit. Load is connected to supply mains through mains current and voltage transducer in parallel with reactive-power source. First output of supply mains current and voltage transducer is connected to input of sync pulse unit. Novelty is that device is provided in addition with desired current computing unit, subtractor, four-quadrant converter control unit, four-quadrant converter, DC voltage source, and switching member control unit; first output of supply mains current and voltage transducer is connected to first inputs of desired current computing unit and of switching member control unit, second output of supply mains current and voltage transducer is coupled with second input of desired current computing unit and with first input of subtractor; output of desired current computing device is connected to second input of subtractor whose output is coupled with first input of four- quadrant converter control unit whose second input is connected to output of sync pulse unit; DC voltage source is connected in parallel with load through four-quadrant converter whose input is connected to output of its control unit; second input of switching member control unit is connected in parallel with reactive-power source capacitor and its output, to switching member. Device tested in type VL65 locomotive has shown reduction in power requirement by 5-7%. EFFECT: enhanced power factor of locomotive. 1 dwg