SU892615A1 - Dc voltage-to-dc voltage converter - Google Patents

Description

(54) CONSTANT VOLTAGE CONVERTER TO PERMANENT

one

The invention relates to converter equipment and can be used in power supplies.

A DC / DC converter with an intermediate AC link is known, containing a series resonant inverter on thyristors, an exponent on diodes, connected to the secondary winding of the transformer fl.

The disadvantage of this converter is that the start-up reliability is not high enough.

The closest in technical essence to the present invention is a DC / DC converter. This contains a resonant inverter, whose input is shunted by a reverse diode, and connected to the input pins via a thyristor key, and its output is connected to the OUTPUT pins via a power rectifier and filter and control unit 2.

. The disadvantage of this converter as well as the circuit is the low reliability when operating in the field of low load currents. This is due to the fact that as the load current decreases, the voltage across the switching capacitor and the reverse voltage across the thyristors, equal to the difference between

10, the sum of the voltages across the switching capacitor and the primary transformer winding and the converter supply voltage is also reduced. This leads to an increase in time.

IS restores the thyristor locking properties, which may cause the inverter to break.

The purpose of the invention is to increase the reliability of the converter.

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Claims (1)

The goal is achieved by the fact that nap-i.n.neit is a constant-to-constant-to-constant converter, but a transistor switch is inserted and turned on opposite to the reverse diode to the inverter input. In the thyristor lock-in interval, due to the fact that the additionally inserted transistor switch short circuits the inverter input terminals, a reverse voltage is applied to the thyristors equal to the sum of the voltages on the switching capacitor and the primary winding of the transformer. The magnitude of the reverse voltage on the thyristors in the proposed circuit is greater than in the known circuits by the amount of the supply voltage, which significantly increases the reliability of the converter. The drawing shows a circuit diagram of a converter. The converter contains an inverter on thyristors 1-4, a series resonant circuit of the inverter consisting of drossel 5 and a capacitor 6, an exponent on 7-IQ diodes connected to the secondary winding of the transformer II inverter, filter 2, main transistor 1) 1Y key 13, reverse diode 14, additional transistor switch 15 and control unit 16. The converter in the steady state operates as follows. Control unit 16 receives control pulses for unlocking. thyristors 1 and 4 and at one time energized, opening the main transistor power 13 and locking additional key 15, and a sinusoidal current pulse is formed in the circuit of the resonant circuit. At the same time, when the thyristors 1 are unlocked, the diodes 7 and 10 of the output rectifier open and the capacitor 6 is recharged to a voltage with the inverse polarity of the initial one, and the condensate filter of the filter 12 is recharged. At the end of the oscillation half cycle, the control unit 16 locks the main key 1 and opens an additional key 15. At the same time, a reverse voltage equal to the sum of the voltages on the capacitor 6 and the phasing of the transformer 11 is applied to the thyristors 1-4. There is an intensive restoration of the thyristor locking properties 1–3 and further, during the entire pause, a high reverse voltage is maintained on the thyristors. 54 In the next half-cycle, control unit 16 again opens the main key 13 and locks the additional key 15, and also switches on the control pulses to turn on the thyristors 2 and 3 of the other leg of the inverter. At the same time, diodes 8 and 9 of the output rectifier open and a half-wave of the output inverter of opposite polarity is formed. In the following, all processes in the converter are repeated. As can be seen from the operation of the circuit, at all the stage of locking thyristors from the circuit of the resonant circuit, the power source of the converter is excluded, the voltage of which is directed opposite to the locking, therefore, in the proposed circuit, the reverse voltage is much higher than in the known ones. As a result, the converter remains operable even in modes when the blocking voltage is collapsing from the voltages on the capacitor 6 and the primary winding of the transformer I1, is smaller in magnitude than the power supply voltage. This mode is possible when starting the converter, as well as when using the main transistor 13 as the power switch of the pulse controller. For normal operation of the converter, the control unit 16 must produce short control pulses to turn on the thyristors 1-4 of the inverter and the voltage to control the transistor keys 13 and 15. The control voltage of the transistor center 13 represents the opening pulses of the beginning of which are synchronized with control pulses to thyristors, and their maximum duration should not exceed the half-life of the inverter minus the circuit recovery time history. The release voltage to the transistor switch 15 is applied at the time of locking the main switch 13 and removed at the time of unlocking the latter. Thus, the use of an additionally introduced transistor switch ensures reliable operation of the DC / DC converter in a constant over a wider range of loads than the known similar devices. The installed power of the additionally introduced transistor switch is much less than the installed power of the main one, since it only works for a short interval to lock the thyristors, and its maximum current, equal to the amplitude of the reverse current of the thyristor, is much less than the amplitude of the direct current pulse. Claims of the Inverter DC to DC Converter Containing a Resonant Inverter whose Input is Shunted by a Reverse Diode and Connected to Input Relays via a Transistor Switch, and its Output is Connected to Output Outputs via a Power Distributor and a Filter and Control Unit Different that, in order to improve reliability, parallel to the inverter input, a transistor switch, which has been additionally inserted and switched in opposite to the reverse diode, is connected. Sources of information taken into account during the examination 1. USSR Author's Certificate No. 547941, cl. H 02 M 3/315, 1975. 2, USSR Author's Certificate for Application No. 270273 / 24-07, cl. H 02 M 3/38, 1978.  ff16 t .