RU94035139A - Voltage converter - Google Patents

Abstract

FIELD: electric engineering, secondary power supplies. SUBSTANCE: device has output complex transformer TVwhich magnetic circuit has working core 1 which section area is Sand which is made from non-saturating magnetic material which magnetization rate is linear, and control core 2 which section area is Sand which is made from saturating magnetic material which hysteresis loop is shaped as rectangle. Said cores are embraced by turns of primary windings. In addition each core is separately embraced by turns of output windings Wand Wwhich number of turns conforms to equation: S/S= W/W. Said output windings are connected in series aiding and are connected to load resistor. Said Feedback windingsembrace only control core 2 and are connected in series opposing to output windingsof transformer of master generator. One terminals of latter output windings are connected to each other, another ones are connected to emitter-base junctions of power transistors VT(VT) through base resistors. In addition base terminals of transistors are connected to anodes of by-pass diodes VDand VDwhich cathodes are connected to common point of feedback windings and windings of transformer of master generator. When circuit of master generator is supplied by current, one transistor (for example, VT) is rendered conducting and collector current runs through winding. This current alters magnetization of cores, firstly working core 1, then control core 2 alter their magnetization. Because number of turns in windings Wdiffers from that in W, magnetization of working core takes either longer or shorter when load is switched on. The first is the case when load current increases its level with respect to nominal one. The second is the case when load current decreases its level with respect to nominal one. In winding Wthis results in inducing relative electromotive force ewith varying relative pulse duration and constant amplitude (because U= const). Level (finish) of magnetization of working core is determined by start of alternation of magnetization of control core 2 when magnetic field intensity in latter reaches level which is proportional to load current. When core 2 starts alternation of its magnetization, conducting voltage of master generator transformer is locked and conducting transistor is rendered non-conducting by means of locking voltage from feedback winding. This finishes process of generation of half- period of output voltage. So, stabilization of output voltage of converter is achieved by average voltage level for half-period by means of variation in relative pulse duration in voltage which controls power transistors. Device may be used as voltage stabilizer. EFFECT: simplified design of gate control circuit because stabilization of output voltage is achieved by implementation of pulse-duration modulation at elements of output transformer. 1 dwg

Claims (1)

The purpose of the invention is to simplify the control circuit of the converter keys to stabilize the output voltage by implementing the PWM method on the elements of the output transformer. The voltage converter consists of an output composite transformer TV ₁ , the magnetic core of which contains two cores: a working one with a cross section S _p and a control core 2 with a cross section S _y . Feedback windings cover only the control core 2 and are connected in series-opposite to the output half-windings of the transformer of the master oscillator, some ends of which are connected together, while others are connected through the base resistances to the emitter-base junctions of the power transistors VT ₁ (VT ₂ ). In addition, the anodes of the shunt diodes VD ₁ and VD ₂ are connected to the base terminals of the transistors, the cathodes of which are connected to the common connection point of the feedback windings and the transformer windings of the master oscillator. The degree (end) of magnetization of the working core is determined by the beginning of the magnetization reversal of the control core 2 when the specified magnetic field strength is reached in the latter, which is directly proportional to the load current. Thus, the output voltage of the converter is stabilized by the average value of the voltage per half-cycle by changing the duty cycle of the control voltage to power transistors.