SU1436231A1 - Variable voltage converter - Google Patents

Abstract

This invention relates to electrical engineering and can be used as a secondary power source. The purpose of the invention is to increase reliability and simplify coordination with a control device based on a phase-pulse modulator. For this, an adjustable converter containing an output transformer 1, two pairs of power switches 2, 3 and 4, 5, a control switch 14, a choke 13, a diode 9, a capacitor 7, a control switch 15, a diode 10, And 12, and a capacitor 8 are entered The purpose of the invention is achieved by the new implementation of the regulating unit, its connections with the circuit elements, the connection of the power switches 2, 3 of the first pair not parallel to the second pair, but through capacitors. Due to this, the voltages on the diodes, control keys and power keys of the first pair are reduced, and the long-term activation of these keys does not cause the remaining circuit elements to fail. Diodes 11, 12 protect the regulation keys from reverse voltage and ensure the formation of a latitudinal-modulated pulse signal from the phase-modulated signal, which simplifies the matching of the converter with the control device. 2 Il. (C sl

Description

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The invention relates to electrical engineering and can be used in the development of stabilizing transistor sources: secondary power supply on the basis of pulsed regulators with an incomplete modulation depth of the input voltage.

The purpose of the invention is to increase reliability and simplify coordination with a control device based on a phase-pulse modulator.

FIG. 1 is a schematic diagram of a variable voltage converter; in fig. 2. - voltage plots, which explain the operation of the converter, whose indices correspond to the designations of the elements in the diagram.

The adjustable voltage converter contains an output transformer 1, the primary winding of which includes the air supply between the power switches 2 and 3 of the first pair and the power switches 4 and 5 of the second pair, and the secondary winding is connected to the output terminals 6, capacitors 7 and 8, diodes 9-12 , choke 13 and control keys 14 and 15.

FIG. 1, return diodes protecting the power switches 2–5 from overvoltages that occur when switching inductive circuits are not shown.

The adjustable voltage converter operates as follows.

The power switches 2-5 for switching them are supplied with rectangular-shaped control voltages (Fig. 2a, b), which alternately, through the control voltage half-period, open either keys 2 and 4, or keys 3 and 5, connecting the primary winding the output transformer 1 to the primary power source either to the capacitor 7 or through the capacitor 8. From the secondary winding of the output transformer 1, alternating square voltage is fed to the output pins 6. Transformation ratio between the secondary and primary windings of the transformer The armature I is selected based on the requirement of obtaining the required output voltage.

The control switches 14 and 15 receive control voltages (Fig. 2c, d), shifted in phase with respect to the control voltages supplied for switching the power switches 2-5. The opening and closing of the keys 14 and 15 occurs alternately through the half-period of the control voltage that is phase-shifted.

In the process of switching power and control switches, phase-shifted control voltages, four different combinations of their states are possible, two of which correspond to the process of energy accumulation by the choke 13, and two to the process of its recoil.

The process of energy accumulation by choke 13 is possible when power is open.

keys 2 and 4 and regulating key 14, or when power switches 3 and 5 and regulating key 15 are open. If the process of energy accumulation does not proceed, then the process of its return occurs. The return of the energy accumulated by the choke to the load and the capacitors 7 and 8 occurs through diodes 9 and 10, which open according to the law of continuity of the current flowing through the choke. In the converter, the pulse-phase signal is converted into a pulse-width signal by switching diodes and 12 voltages, which is received at the primary tap of the output transformer 1. If

r regulating key 14, but power switches 2 and 4 are closed, and keys 3 and 5, respectively, are open, then diode 11 will be closed, since the voltage on its anode will be lower than on the cathode. The same thing happens with diode 12 if

0 the control key 15 and the power keys 2 and 4 will open.

Thus, the duration of the processes of accumulation and energy delivery by the choke 13 at each half-period of the control voltage switching the power switches 2-5 uniquely depends on the phase shift between the control voltages supplied to the power and control switches.

Upon expiration of a certain number of control voltage periods in the converter, a state of dynamic equilibrium occurs, in which the average currents through the capacitors 7 and 8 over time are equal to zero. In this case, the average for the period of the voltage on the choke 13 is also zero.

At the minimum possible value of the transformation ratio of the primary winding of the output transformer 1, the minimum energy load takes place

0 converter elements and, as a result of this, minimal losses and increased reliability. The transformation ratio should be chosen from the condition that the voltage drops to zero.

c on the choke 13 at the stage of energy storage, since in this case the required adjustment capabilities of the proposed converter will be used to the maximum extent.

50

Claims (1)

Invention Formula An adjustable voltage converter containing an output transformer connected to the output terminals, the first and second pairs of consecutively connected power switches, the first regulating switch, the first terminal of which is connected to the output winding of the output transformer, and the series-connected choke, the first diode and the first a capacitor, with the connection points of the power switches of the first and second pairs connected to the beginning and end of the primary winding of the output transformer, the connection point of the first diode and the first the capacitor is connected to the free output of the first power switch of the first pair, and the free output of the first power switch of the second pair is connected to the first input output, characterized in that, in order to increase reliability and simplify coordination with the control device based on the phase-pulse modulator, the second control key, the second, third and fourth diodes and the second capacitor, and 0 five The free output of the throttle is connected through the second diode and the second capacitor in series with the first input terminal, the second input terminal is connected to the free terminals of the first capacitor and the second power switch of the second pair, the junction point of the second diode and the second capacitor is connected to the free output of the second power switch of the first pair, The first pin of the second regulatory key is connected to the first pin of the first regulatory key, and the second pins of the first and second regulatory keys are via the third and fourth d The iodines are connected respectively to the points of connection of the throttles with the first and second diodes. g V ,, r Search ag.1