SU1508326A1 - Single-ended d.c. converter - Google Patents

Abstract

The invention relates to secondary power sources. The purpose of the invention is to reduce the dynamic losses in a single-ended converter. This is achieved by introducing a self-oscillating mode of the power transistor 1 due to the additional winding 9 of positive feedback to the single-cycle DC / DC converter with accelerated active demagnetization of the transformer 4 core, and the rectifier of the rectified voltage is controlled by reducing the demagnetization rate transformer core 4. To do this, in series with the demagnetizing winding 6, transistor 13 is turned on, controlled by the resistance of the optocoupler 12, light radiating element is connected to the output of the control unit 3. 2 yl.

Description

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The invention relates to electrical engineering and can be used in secondary power systems.

The terminal of transformer 4 has a negligible value. Since siotona winding 5 has the number of turns per carried

The conversion of a constant voltage is from a few times less than the demagnetization of one value into a constant stabilized voltage of another value.

The purpose of the invention is the reduction of dynamic losses.

On. Fig. 1 shows a circuit diagram of a single-ended DC / DC converter; in fig. 2 time diagrams of voltages on a toric winding 15 after rectifying.

The single-ended DC-DC converter contains a power 1 and commuting 2 transistors, a control unit 3, a transformer 4 that includes a power 5 and a demagnetizing 6 windings, a positive feedback winding 7, a secondary winding 8, an additional winding 9 positive feedback , a resistor 10, a current-limiting resistor 11, a resistive optocoupler 12, a transistor 13, a power diode 14, bcf flash 15–17, input pins 18 and 19, and output 20 and 21.

FIG. 2 accept the following notation; and and and

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t and t

   secondary secondary

voltage, respectively, at elevated and low voltage pi--: 5 tons / rot;

 - time of the reverse magnetization reversal of the core, respectively, with an increased and decreased voltage of -40 ni J

UH is the load voltage. A constant-voltage single-phase converter operates as follows .45

When the power transistor 1 is turned on, the remagnetization of the transformer 4 core is initiated, and the energy from the power source through the power transistor 1 and the power diode 14 is transformed to the load. When transformer 4 is pressed, transistors 1 and 2 switch and, through transistors 2 and 13, the core of transformer 4 begins to reversal in the opposite direction. In this case, transistors 2 and 13 only go through the magnetizing TOIC, which with a rectangular hysteresis loop of the material of the ser50

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winding 6, the reverse magnetization reversal of the core goes so much faster. The speed and, consequently, the rewinding time are adjusted with the help of transistor 13. When the supply voltage is low (Fig. 2), the resistance of the optocoupler 12 is minimal, the transistor 13 is fully open, the speed of reverse magnetization is maximum, and therefore, the reversal time is also the minimum. When the supply voltage is increased, the resistance of the optocoupler 12 increases, the resistance of the transistor 13 increases, the voltage on the demagnetizing winding 6 decreases, the speed of the reverse magnetization of the core decreases, and the time of the magnetization of the vanes increases. Since the volt-second area of the positive half-cycle does not change when the value of the power supply voltage varies, by adjusting the time intervals with these half-periods using the LCD filter 15 and 16, you can keep the average voltage constant.

In the proposed single-cycle DC-voltage converter, the demagnetization rate of the transformer core is always less than the maximum and is determined by the stabilization conditions, the required filling factor of the rectified voltage, which leads to a decrease in the dynamic magnetization losses and a decrease in high reverse voltages on the power transistor and power diode

Claims (1)

Invention Formula A single-ended converter of voltage, containing a power and switching transistors, a control unit, a transformer that includes a series-connected power and demagnetizing windings, common current connected to one input terminal, a positive feedback winding connected through a controller resistor the input of the switching transistor, the secondary winding connected through a series winding 6, the reverse reversal of the core goes as many times faster. The speed, and therefore the reverse magnetization time, is regulated with the help of transistor 13. When the supply voltage is low (Fig. 2), the resistance of the optocoupler 12 is minimal, the transistor 13 is fully open, the reverse magnetization speed is maximum, and therefore, the remagnetization time is also minimal. With an increased supply voltage, the resistance of the optocoupler 12 increases, the resistance of the transistor 13 increases, the voltage on the demagnetizing winding 6 decreases, the speed of the reverse magnetization of the core decreases, and the time of the magnetization reversal is taken into account. Since the volt-second area of the positive half-period does not change with a change in the value of the supply voltage, by adjusting the time intervals with these half-periods using the LCD filter 15 and 16, it is possible to keep the average value of the voltage constant. In the proposed single-ended DC-DC converter, the demagnetization rate of the transformer core is always less than the maximum and is determined by the stabilization conditions required by the filling factor of the rectified voltage, which leads to a decrease in the magnetic flux losses and a decrease in high reverse voltages on the power transistor and diode. Invention Formula Single-ended DC / DC converter containing power and switching transistors, control unit, transformer, including series-connected power and demagnetizing windings, common point connected to one input terminal, positive feedback winding connected through a resistor to the control input of the switching a transistor, a secondary winding connected in series connected power diode and bcb filter to the output pins and the input of the control unit, the power transistor is connected between the other input terminal and the free output on the free output of the power winding, the switching transistor is connected to one free output of the demagnetizing winding, characterized in that, in order to reduce the dynamic losses, current-limiting are introduced into it. resistor, resistor t /; /.-A. an optocoupler, an additional positive feedback winding and a transistor connected between another output of the switching transistor and another input, the collector-base junction of the transistor is connected to the output of a resistor optocoupler, the input connected to the output of the control unit, an additional positive feedback winding through the current limiting A resistor is connected to the control input of the power transistor. t i n / 7, g / and {pus.2