SU1377983A1 - D.c. voltage converter - Google Patents

Abstract

This invention relates to electrical engineering and uses in secondary power supplies. The aim of the invention is to improve the mass and size: x performance and increase efficiency. The device contains an autonomous parallel thyristor voltage inverter 2 with an output rectifier 18 and an inductive capacitive filter 19, the operating frequency control system 25 is connected to a voltage source 24. A load current linear feedback loop includes a shunt 22 in the load circuit and an amplifier 23. The magnitudes of the transmission coefficients of the control system and the feedback node and the driving voltage are selected according to the idling and rated load conditions such that in both cases the operating frequency of the inverter corresponded to the inclusion of the next thyristors at the time when the currents of the inverter inductors reach their current value equal to the rated load current of the inverter transformer for the number of turns of the primary winding of the inverter transformer. 3 il. about. & (L

Description

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The invention relates to power converter technology and can be used in the development of medium and high power DC / DC converters.

 The purpose of the invention is to improve the mass and overall performance and improve efficiency.

FIG. Figure 1 shows a circuit diagram of a constant voltage converter with an autonomous parallel thyristor voltage inverter; in fig. 2 - curves: a - current i in current-limiting chokes x at nominal load current; b - voltage Uj at the switching capacitor and the primary current of the inverter transformer at rated load current; in - current ij in current-limiting droplets x in the mode: idle; d is the voltage U on the switching capacitor in idle mode; in fig. 3 - f - inverter working frequency; the current in the current-limiting chokes at the end of the interval for the return of excess energy from the current-limiting chokes at a variable operating frequency, depending on the value of the load current of the source in relative units.

The DC voltage converter contains a DC voltage source 1, a stand-alone parallel thyristor voltage inverter 2, which includes a reverse current diode bridge 3 connected by a DC diagonal to the same-voltage terminals of the DC voltage source 1, current-limiting chokes 4 and 5, thyristor bridge 6 with thyristors 7-10 and switching capacitor 11 in the diagonal of alternating current connected via current-limiting chokes 4 and 5 to the terminals of opposite source polarity of the source a voltage of 1 diagonal direct current, a transformer 12 with a primary winding 13 with three sections 14-16 and a secondary winding 17; , an output rectifier in the form of a diode bridge 18, connected by a diagonal of alternating current to the secondary voltages of the

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a coil 17 of a transformer 12, an inductive-capacitive filter 19 connected to the DC diagonal of a diode bridge 18, a load 20 connected to the output terminals of the filter 19, a linear current feedback node 21 with a shunt 22 connected in series with the load and an amplifier 23 connected by an input to the shunt, a source of voltage setting 24; a control system with an operating frequency of 25, one input of which is connected to the source. The voltage of its voltage is 24, and the other is connected to the output of the amplifier 23, the four inputs of the control system are connected to the control electrodes of the thyristors 7-10.

The converter operates as follows.

When the thyristors 7 and 10 are on, a positive voltage half-period is formed on the secondary winding 17 of the inverter transformer 12, and negative when the thyristors 8 and 9 are on. The amplitude of this voltage is proportional to the amplitude of the voltage, and the densator

f. on the switching terminal - 11 inverter 2 on the interval

le tg (fig. 2) return of excess energy from current-limiting chokes 4 and 5. Voltage (1 + + 2 K), E, where E is source voltage 1. The next thyristor pair is turned on under the influence of output voltages U, control systems 25. Turning on the next pair of thyristors leads to turning off the previously switched on pair of thyristors under the influence of voltage Up on the recharging on the switching interval tjj in the inverter switching capacitor 11. At the moment of

when the voltage U is passed, the current i is switched through the primary winding 13 of the transformer 12 through a zero value (Fig. 2). Under the influence of the voltage supply source 24 and the voltage UQC of the feedback node 21, the control system 23 generates output voltages 1) with a frequency f proportional to their sum, i.e. the frequency f K | (iu, d +) linearly depends on the magnitude of the current 1, the load 20 of the converter. The magnitudes of the coefficients K and K and the voltage and, 0d are set such that at rated load, when

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and at idle when the frequency K, (and, a +

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chokes 4 and 5 are the numerical value of the rated load current given to the number of turns of the primary winding 13 of the transformer 12 (Fig. 2).

When installed in this way

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the values of K ,, K load current 1c to zero inverter frequency f linearly decreases from f

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The current limiting chokes of x 4 and 5 at the moments of the next switching on of thyristors 7, 10 or 8, 9 remain almost unchanged throughout the entire range of current variation of the load of the converter 20 (curve 27, Fig. 3).

Thus, an increase in the operating frequency and a limitation of the power loss of electrical energy in the inverter, hence, an improvement in its mass-dimensional parameters and an increase in efficiency, is achieved in the DC / DC converter.

Claims (1)

Formula from formula A constant voltage converter containing a stand-alone parallel thyris connected to the input terminals via filter chokes to f5 inverter with reverse rectifier, output rectifier with inductive-capacitive filter connected to the load circuit, control system of the inverter operating frequency, the input of which is connected to the source of the driving voltage, characterized in that, in order to improve the weight and dimensions and increase The efficiency is provided with a feedback node for the load current of the converter, which includes a shunt in the load circuit of the converter, and an amplifier connected by the input to the shunt and. output to the input of the control system setting the frequency of the inverter f k, (and, „d + K ,, ij. 20 five 0 five where f is the frequency of the inverter; K, is the transmission coefficient of the control system; Ujc ,, is the driving voltage; Kg is the transmission coefficient of the feedback node; 1 C - load current moreover, the values of the transmission coefficients K, and K2. and the drive voltage is chosen so that the inverter thyristors during idling and rated converter load are turned on at times when the currents of the inverter current-limiting chokes take values equal to the rated load current of the converter converted to the number of turns of the inverter transformer primary winding. t / f lltfiot fju fwg m0, 2 Qtf fie.Z Uem Off 0, S 7.0 If / jlHOii