FREQUENCY CONVERTER WITH DC SWITCHING DEVICE Russian patent published in 2024 - IPC H02M5/45 

FIELD: electrical engineering; metallurgy.

SUBSTANCE: proposed invention relates to equipment for induction heating and melting of metals. Frequency converter consists of two-bridge 12-pulse rectifier, input terminals of which are connected to secondary windings of power transformer, and DC poles are connected in parallel through windings of double-winding smoothing reactors and connected to input terminals of current inverter, output clamps of which are connected to the load shunted by the compensating capacitor. Novelty in the proposed converter is that its circuit additionally includes three thyristors forming a rectifier DC switching device, one of which is connected in series to the DC circuit between the rectifier bridges through the smoothing reactor windings, common outputs of which are connected to this thyristor through two other additional thyristors and other windings of smoothing reactors with similar poles of direct current of rectifier bridges. In addition, the additional thyristors control unit supplies to the first of the additional thyristors control pulses with an adjustable delay, and to the other two—simultaneously with the inverter thyristor control pulses.

EFFECT: improved quality of consumed electric power and reduced weight and dimensions of smoothing reactors.

1 cl, 3 dwg