IMPROVED FREQUENCY DOWN-CONVERTER Russian patent published in 2016 - IPC H02M5/27 H02M5/275 H02M5/297 H02P27/04 

FIELD: electronic equipment.

SUBSTANCE: invention can be used in systems of electric drive with reduced rotation frequency, as well as in dewaxing of oil wells. Method is used in frequency converter control multiphase reversible bridge connected to secondary circular winding of transformer with rotating magnetic field, where pulse-phase control system ensures growing delay of key control signals, switching branches of circular winding, relative to phase supply mains. Switching is performed between pairs of branches, at moment of equality of their EMF, which provides low frequency fundamental harmonic of output voltage and current curve there is no gap in circular winding taps switching.

EFFECT: technical result is increased reliability due to absence of rupture of current in power circuit, higher quality of output voltage and high electromagnetic compatibility of device with supply mains.

1 cl, 3 dwg