SU1069103A2 - Constant voltge converter - Google Patents

Description

The invention relates to a conversion technique and can be used in power supplies of radio electronic equipment. According to the main author, No. 811464, a direct voltage converter is used, which contains an inverter cell made on power transistors, one of whose power electrodes is connected to an input terminal, a transformer, a control unit with an output control transformer, one of which secondary windings with a series-connected resistor is connected to the base-emitter junction of the corresponding transistor, the base-collector junction of which is shunted by a chain of series-connected transistor bmotki and a diode, with saturating inductor configured multiplex and each of its winding included in said chain shunt Bazo-collector transition of the corresponding transistor, wherein a QUALITY ve transformer windings in the secondary chain used obmot ka controlled kvdego transformer. The special feature of such a converter is that the power transistors are in the saturation mode most of the time in the open state and only before the switching moment are transferred to the active (boundary) mode ij. However, due to the considerable variation in the parameters of the circuit elements depending on the operation mode of the power transistors and the ambient temperature, significant asymmetry may occur in the operating mode of the output transformer, which can lead to its saturation, especially when operating at high frequencies, resulting in a decrease not only performance, but also the efficiency of the device. The aim of the invention is to increase the efficiency of a constant voltage converter by balancing the mode of operation of the output transformer when the ambient temperature varies widely, regardless of the mode of operation of the power transistors, the goal is achieved by sequentially converting each primary voltage to each primary voltage. A transformer magnetizing current sensor is connected to the winding of the power transformer. It is connected to the input of the input protection node, the output of which is connected to al lel more multiplex winding saturable choke. Fig. 1 shows a schematic of the proposed DC / T converter; Fig. 2 illustrates stress plots. The converter contains power transistors 1, the base-collector transitions of which are connected via diodes 2, to the control transformer 3 with secondary 4, additional 5 and synchronizing 6 windings, multiwinding saturating choke 7 with regulating 8 and additional 9 windings, current transformer sensor 10 connected to the input of the comparison node 11 with the output transistor 12, the pulse shaper 13, which contains the trigger 14, the amplifying 15 and the closing 16 transistors, the converter load 17 through the winding 18 of the sensor 10 Connected to the secondary winding of the output transformer 19. The DC / DC converter operates as follows. In the symmetric mode, the power transistors 1 during the time io 0, 0.5T), determined by the duration of the remagnetization of the core of the throttles 7 under the action of the voltage e U5-Ug-Us-3su, R8, (} E1 is in a saturated state, and during the time ((go, 5T-io, (io ,, -o, 5T -t,) in the active boundary) region, where Ug is the voltage applied to the winding 8 droplets 1, is the voltage; windings 5 transformer 3 / voltage drop across open diodes 2 and the base-collector junction of saturated transistors 1 3 | у, - magnetizing current droplet 7; Sg - cC1 winding resistance 8 drossa 7. In this case, the transistors 12 and 16 of the comparison unit 11 and the driver 13 are closed, respectively, and the winding 9 of the cable 7 does not affect the time of its reversal. , with the result that the transistor 12 of the comparison node 11 is opened and the winding 9 of the throttle 7 through the transistor 16 forms the body 13 is shorted. A voltage across the winding 5 of the transformer 3 is applied to the base-collector junction of the oversized transistor 1 through diode 2, biasing it in the opposite direction. The saturated transistor 1 goes into active (edge) mode. A change in the duration of the transistor 1 in the saturated state to) leads to a change, in volt-seconds, of the voltages on the windings of the power transformer 19, compensating for non-voltage / metry.

at the beginning of each half cycle, the transistor 16 of the driver 13 is turned off by the transistor 15, which is opened for a short time by the voltage coming from the winding 6 of the transformer 3.

The circuit provides detection of the oncoming saturation of the core of the power transformer 19 even before its occurrence, when the increase in the collector current of transistors 1 is not very noticeable, which is achieved at

assistance of a current sensor, the voltage amplitude at the output of which is proportional to the magnetizing currents of the transformer windings 19.

Excluding the one-sided saturation mode of the output transformer reduces the dynamic power losses in the power transistors and eliminates the current pulses through them, which increases the efficiency and reliability of the DC / DC converter.

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Claims (1)

DC CONVERTER by ed. No. 811464, powered by the fact that, in order to increase the efficiency, a magnetizing current transformer is connected in series with the primary winding of the power transformer, connected to the input of the introduced protection unit, the output of which is connected in parallel with the additional winding of the multi-winding saturated inductor.