SINUSOIDAL-TO-REGULATED-DC VOLTAGE CONVERTER Russian patent published in 2004 - IPC

FIELD: converter engineering. SUBSTANCE: converter that can be used as low-voltage power supply for various electrical and electronic devices has pair of input terminals 1', 1" for connection to sinusoidal-voltage supply and pair of output terminals 2', 2" for connection to load; parallel-interconnected filter capacitor 7 and output of rectifier 3 connected to terminals 1', 1"; series-interconnected two-way controlled switch 4 and primary winding of isolating transformer 6 whose secondary winding is connected to input of rectifier 3; control voltage shaper 5 whose input is connected to input terminals 1', 1" and output, to control input of two-way switch 4. The latter is, essentially, transistor switch and pulse shaper functions as control voltage shaper which is placed in operation when sinusoidal voltage crosses zero at length inversely proportional to supply voltage amplitude. Control pulse train generated in the process actuates control switch 4 to enable servo gating of supply voltage across primary winding of isolating transformer 6 in step with supply mains. This gating provides for arrival of equal portions of ac supply energy at filter capacitor 7 to maintain constant level of desired reduced voltage across this capacitor. Mentioned design of converter provides for using near-zero supply voltage intervals to unload supply mains during other sinusoidal-voltage moments which enables reducing its mass and size. Facilitated manufacture of isolating transformer 6 is ensured due to approaching its transformation ratio to unity and making both its windings of large-diameter wire with few tens of turns. Such wire along with provision for taking supply voltage off primary winding as it crosses maximum eliminates turn-to-turn faults and open circuits in windings and augments heat transfer from deep areas of isolating transformer. Transistor used as two-way switch handles heavy currents at low frequency of supply voltage. Small number of winding turns essentially reduces leakage inductance and, hence, voltage surge amplitude during primary winding change-over which makes it possible to use transistor rated at comparatively low maximum permissible voltage. EFFECT: ability of extending operating voltage range of converter toward low and high values of supply voltage due to its ability to function at about-zero intervals of supply voltage. 1 cl, 8 dwg