SU928326A1 - Stabilizing dc voltage converter - Google Patents

Description

one

The invention relates to electrical engineering and is intended for use in power supply devices for automation and computer technology.

Voltage stabilizing converters are known, which include a transistor inverting circuit, operating in a push-pull mode, a transformer with an output rectifier, connected to the output after it, an inductive-capacitance filter, and a control and protection device.

The disadvantages of these converters are relatively low efficiency, low reliability, large size, which is explained by the presence in them of additional pulsed power losses from through currents and a biasing transformer, the complexity of the circuit.

The closest in technical essence to the invention of bullets

A voltage stabilizing converter containing two transistor key elements connected to the potential input terminals, a transformer with a rectifier, two diode circuits and a series-connected filter choke and a filter capacitor to which the control and protection unit of the HZ is connected.

ten

The disadvantages of this converter are low efficiency, low reliability, large size.

The purpose of the invention is to increase efficiency, reliability, size reduction.

five

The goal is achieved by the fact that in a stabilizing voltage converter containing two transistor key elements connected to different-potential input terminals, a transformer circuit with a main rectifier, two diode circuits, a choke and a filter capacitor connected to it by the Control and Protection Plot, transistor key the elements are connected through a filter choke between the cable and through the entered middle point of the throttle - to the input of the transformer circuit, with two of the same power output transistors key elements are interconnected respectively through two diode circuits inserted, the auxiliary input of the transformer circuit is connected via a control unit to the control and protection unit, the auxiliary output of the transformer circuit is connected to the main rectifier through an additional rectifier, and both rectifiers are connected to the filter capacitor . FIG. 1 shows a structural scheme of a stabilizing transform; 1 e of LL, constant voltage; Fig.2to the same, a simplified version. The DC voltage stabilizing converter contains transistor switch 7 elements 2 and 3 connected to variable potential input terminals 1, connected to a diode circuit D and 5, filter choke 6, the midpoint of which is connected to a transformer circuit with transformers 7 and 8, connected to the main 9 and additional 10 issues. The rectifiers are connected to the co-filter of the filter 11 and the block y, p and protection 12, connected to the control unit 13, in which transistor 1 and rectifier 15 are located. Elements 2 and 3 with capacitors 16 and 17 form a half-bridge inverto . The output voltage of the converter is removed from the capacitor M through the terminals 18. The stabilization converter of the constant voltage converter works as follows. When the supply voltage is applied to the clamps 1 (Fig. 1), rectangular control pulses simultaneously begin to arrive alternately onto the ele- ments 2 and 3, as a result of which the nocV latter are alternately transformed into a saturated or de-energized state. At the same time, each of the capacitors 1b and 17 is charged to about half the supply voltage. As a result of the alternating switching of 9 elements 2 and 3, the primary voltage of transformer 7 and 8 produces a alternating voltage, which, after transformation and spraying with rectifiers 9 and 10, begins to charge the capacitor 11, and the charge rate of the latter, a, therefore, the amplitude of the currents through the elements 2 and 3, 7-10 is limited by the choke 6. The magnitude of the output voltage of the converter (on the capacitor 11) is stabilized at a predetermined level using the feedback circuit of elements 12-15. If the voltage at the terminals 1 is minimum in magnitude, the control and protection unit 12 acts on the control unit 13 so that its transistor 1 is kept in a saturated state. As a result, the transformer 8 is short-circuited through rectifier 15 and transistor Topj, the voltage drop across its primary winding and at the input of rectifier 10 is close to zero, and the voltage from the output of the inverter through transformer 7 and rectifier 9 goes to output terminals 18 and capacitor 11. At the maximum voltage value at the terminals 1, the block 12 holds the transistor 14 in a de-energized state. In this case, the current through the rectifier 15 does not flow, the voltage on the output terminals 18 flows through both the rectifier 9 and 10, and the output voltage of the inverter is distributed between the primary windings of the transformers 7 and 8 proportionally to their transformation ratios. The latter are chosen so that in this mode of operation the voltage at terminals 18 is equal to the initial (specified) value. At intermediate values of the voltage at terminals 1 by means of block 12 and 13, the transformer 8 is more or less shunting effect, as a result of which the voltages between transformers 7 and 8 are redistributed, and the voltage at terminals 18 is maintained equal to the predetermined value. Transistor 14 and unit 13 can operate in continuous or pulse width control mode. The decrease in the variable component voltage at terminals 18, i.e. ripple smoothing is achieved with the help of droplets of the filter 6, which maintains a constant amplitude current in the transducer circuits, and the filter capacitor 11. In the bottom modes of operation, no currents flow through the diode circuits t and 5. In case of accidental or emergency disappearance of control element pulses 2 and 3, or when the converter is disconnected, when voltage is generated on the windings of the throttle 6, the diode circuits k and 5 open and the excess electromagnetic energy of the throttle 6 returns to the power supply (clamps 1) that protects elements 2 and 3 from overvoltages. When a through-current or a pd-magnetizing transformer appears in the converter, choke 6 limits the current through elements 2 and 3, which protects them from impulse overloads, increases the efficiency and reliability of the converter. When a short circuit occurs in the load of the transducer, the short circuit current in the initial period of time is limited by the choke 6, which protects the converter elements from overload. Subsequently, the alarm control and protection unit 12 disconnects elements 2, 3 and 13. When the control unit 13 is operating in the pulse-width control mode, the boost-voltage output voltage control mode implemented in this converter (by switching the transformer 8, the input I a series circuit of transformers 7 and 8) allows reducing the dimensions of the smoothing filter and the converter as a whole, as well as reducing the amplitude of the generated switching interference, and, consequently, the dimensions of the interference suppression filters (not shown).

This converter can also use 45 bridges of the inverter. In this case, instead of a series circuit of capacitors 1b and 17, there is included a second circuit of two transistor switching elements, a diode circuit with a middle point, similar to the circuit of elements 2-6, connected and switched identically.

When using this converter for powering the load, low power, when it is unreasonable to use booster voltage, is possible. regulation, the scheme of the proposed converter can be simplified (Fig. 2). In this embodiment

283266

Transformers 7 and 8 are interconnected, rectifiers 9 and 10 (Fig. 1), and the functions of the regulating unit 13 perform transistor 5 switching elements 2 and 3. The principle of operation of the converter in FIG. 2 is similar to the previous one.

Compared to the known, the proposed Q converter has a higher efficiency, reliability, and smaller dimensions, since the inclusion of filter throttles (relatively large inductance) in the transistor J5 switching elements circuit allows it to effectively protect the latter from impulse overloads, in through-current modes and bias transformers reduce the amount of commutation interference. A voltage boosting control method, implemented by the series connection of transformers in a transformer circuit, allows

25 to reduce the dimensions of the Smoothing.

filter and switching noise. Connecting the output rectifiers directly to the filter capacitor also improves efficiency and reduces switching noise, so

30 as with this, the process of locking the rectifier diodes is accelerated. When changing the polarity of the voltage on the transformer .pax. A smaller number of elements in the converter (Fig. 2) are significantly

5 simplifies the converter.

Claims (1)

Invention Formula A stabilizing device with a constant voltage containing two transistor key elements connected to different potential input terminals, a transformer a circuit with a main rectifier, two di; one circuits, a choke and a filter capacitor with a control and protection unit connected to it, characterized in that, in order to reduce size, increased efficiency and reliability, the transistor key elements are connected through a filter choke to each other and through the entered middle point of the throttle - to the input of the transformer circuit, with two of the same power output of the transistor key elements connected to each other, respectively, via two entered diode circuits, additional