SU930525A1 - Dc voltage-to-dc voltage converter - Google Patents

Description

(54) CONSTANT VOLTAGE CONVERTER TO PERMANENT

The invention relates to devices for converting electrical energy of a constant voltage of one level into a constant voltage of a similar level and can be used, for example, as a power source for auxiliary electrical equipment of rolling stock.

DC / DC converters are known that contain a single-phase half-bridge inverter, a rectifier, a filter, a control pulse generator, a distributor, in which the natural switching of the thyristors Cl and H2 takes place.

The closest to the technical essence of the invention is a DC / DC converter with a stand-alone inverter with a rectifier and a filter, a master oscillator with a prohibition input, a distributor and a threshold element connected between the transducer output and the prohibitor input of the master oscillator. The filter capacitor charge occurs by alternately switching the thyristors of an inverter operating in natural switching mode 31.

However, in such a converter, when the load changes, the natural frequency of the series inverter changes, which, with a constant frequency of the control pulse generator, can lead to a breakdown of the inversion. This reduces the reliability of the converter.

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

Claims (3)

The goal is achieved by the fact that a DC to DC converter contains an autonomous thyristor inverter, a rectifier, a filter, a controlled master oscillator with the Inhibit input, a pulse distributor and a threshold element with a hysteresis, the output of which is coupled to the Inhibit input a master oscillator, a current sensor switched off to the inverter power current circuit, a zero-body whose input is connected to the current sensor output, a delay element whose input is connected to the zero-body output, and a logical two BHD marketing element OR, the first input of which is connected to the output. the threshold element, the second input is to the output of the delay element, and the output is to the input of the Inhibit master oscillator. The drawing shows a block diagram of the converter. The converter contains an auto-inverter 1, for example, a half-bridge type, made on thyristors 2 and 3 with switching capacitors 4 and 5. The output of the inverter through the transformer is rectifier 7 and filter 8 is connected to the output terminals of the converter. A threshold element 9 with a hysteresis is also connected to the output of the converter, the output of which is connected to the first input of the logic element OR 10. Output. element 10 is connected to the input of the inhibitor of the master oscillator 11. The output of the master oscillator 11 is connected via the distributor 12 pulses to the control transitions of the thyristors 2 and 3 of the inverter 1. A sensor is inserted into the power circuit of the inverter 1, for example, in the DC circuit 13, the output of which through the null organ 14 and the delay element 15 is connected with the second input of the lO element. The converter operates as follows. If the voltage on the load coming from the secondary winding of the transformer b of inverter 1 through rectifier 7 and filter 8, is below a predetermined value, threshold element 9 through the element OR OR allows operation of the master oscillator 11. Output pulses of the master oscillator 11 go through the distributor 12 pulses To the control transitions of the thyristors 2 and 3 of inverter 1. When the voltage on the load reaches a predetermined value, threshold element 9 is activated, prohibiting the operation of the master oscillator 11 via the element 10. When the output voltage decreases However, the threshold element 9, having a hysteresis characteristic, returns to its original state, again allowing the master oscillator 11 to work. When unlocking, for example, thyristor 2, an oscillatory overcharge of the inverter capacitor 1 along circuit + power supply source, thyristor 2, occurs; 6, the capacitor 5, the current sensor 13, the power source. When a current flows through this circuit, the signal from the current sensor 13 is detected by a null organ 14, which through the element | 1m delay 15, the OR 10 element locks the master oscillator. After the recharging of the inverter capacitors is over, the current in the power circuit is reduced to zero, the null organ 14 is turned off, however, the master oscillator 11 will be still locked for the time specified by the delay element, which is equal to or slightly longer than the thyristors off time. After the specified time has elapsed, if the output voltage is still below the preset, the master oscillator 11 is turned on again, and the thyristors of the inverter 1 turn on again. Thus, the input elements improve the reliability of the device, since the triggering pulse for the next thyristor cannot be filed before fully locking the previous thyristor, regardless of the load resistance. Claims of a DC / DC converter containing an autonomous thyristor inverter, a rectifier whose input is connected to the inverter output, a filter connected between the output of the rectifier and the output terminals of the converter, controlled by the master oscillator with the Inhibit input, pulse distributor the input of which is connected to the output of the master oscillator and the outputs are connected with the control transitions of the inverter thyristors, and the threshold element with hysteresis, the input of which is connected to the output terminals and the output is connected to the Inhibit of the master oscillator, characterized in that, in order to increase reliability by increasing the time allowed by the thyristors to restore their locking properties, a current sensor connected to the inverter power current circuit is inserted into it, the organ whose input is connected to the current sensor output, the delay element whose input is connected to the output of the null organ, and the logical two-input element OR, the first input of which is connected to the output of the threshold element, the second input to the output of the element aderzhki, and the output - to the input of the master oscillator ban. 5 Sources of information, taken into account during the examination 1. USSR Author's Certificate No. 508878, class, Н О2 3/135, 1973. 930525 b | 2. USSR author's certificate No. 575744, cl. H O2 M 3/315, 1976. 3. USSR author's certificate No. 574832, cl. H 02 M 3/315, 1976.