SU1647544A1 - Device for protecting radioelectronic equipment, primarily secondary power supplies, against starting currents and overloads - Google Patents

Abstract

The invention relates to electrical engineering, in particular to electronic power supply systems. The goal is to increase reliability and efficiency. The device contains. current reading unit 1 with current transformers 2.3 and auxiliary rectifying and filtering unit consisting of 4S5 diodes, filter capacitor 6 and loading resis 4-0 torus 7, key unit 8 with keys 9, 10 and pulse transformers 11, 12, a DC filter 13, a two-phase control unit 14, a two-phase amplifier 15, and an auxiliary source 16 of DC voltage. The voltage taken from the output of the read-current unit 1 is monitored at the control unit 14 and compared there with a reference voltage. If the monitored voltage exceeds the reference voltage, the pulse duration is reduced in inverse proportion. The two-phase pulses from the output of the control unit 14 are amplified by the amplifier unit 15 and the keys 9910 are alternately switched through the pulse transformers 11,12. The currents through the latter flow intermittently, and the average value of the current in the power circuit is limited at a certain level. The galvanic isolation of the signal and power circuits determines the high operational reliability of the device, and the absence of a resistive current sensor in it - low power consumption. 2 Il. and F 1 01 Ј

Description

The invention relates to electrical engineering and is intended for use in power supply systems, such as EV.M.

The aim of the invention is to improve the reliability of the operation and HSC.

Fig, 1 shows a functional diagram of the proposed device; in fig. 2 - time diagrams of signals illustrating its operation.

The device contains a node (Fig. 1) 1 for reading the current with current transformers 2 and 3 and an auxiliary rectifying and filtering unit, consisting of J5 diodes 4 and 55 of the filter capacitor 6 and a loading resistor 7, a key element 8 with transistor switches 9 and 10 and pulse transformers 11 and 12, a DLC filter 13, a two to 20 phase control node 14, a two-phase amplifier node 15, an auxiliary source 16 of a DC voltage. The diagram also shows pins 17 and 18 for connecting a primary 25 constant voltage source current and outputs 19 and 20 for connecting protected electronic equipment, such as a secondary power source. The current reading unit 1, the key element 8 and the DLC filter 13 are connected in series between the terminals. 17-20. The signal input of the control unit 14 is connected to the output of the current sense unit 1, and the output through the amplifier unit 15 is connected to the control input of the key element 8. The outputs of the auxiliary source 16 of the DC voltage are connected to the power inputs of the unit 14 control and amplifier node 15. The primary windings of the current transformer 2 and 3 are connected in series with the keys 9 and 10 to form two parallel branches of the power circuit 5x and the secondary windings 45 are connected to the code (diodes 4 and 5) of the auxiliary rectifier unit and filtering Yield (with filtering capacitor 6) which is the output of unit 1, the read current. The primary windings im-sd pulsed transformers 11 12 constitute the phases of the control input of the key element 8, and the secondary windings are connected to the control circuits of the keys 9 and 10.

The device works as follows.

The voltage taken from the node 1 READING current9 is controlled in uel

55

5 d

five

14 and is compared there with a reference voltage. The control unit 14 continuously generates two antiphase pulse sequences. If the monitored voltage exceeds the reference voltage (on-current modes or over-current modes), the pulse duration is reduced in inverse proportion.

The two-phase pulses are amplified in the amplifier node 15, the load of which is the corresponding primary windings of the pulse transformers 11 and 12. The pulses 11.4, U (Fig. 2, a, b) from the secondary windings of the latter are applied to keys 9 and 10 of the key organ 8, which are alternately switched. Currents ig, iiO (Fig. 2, c, d) through the keys 9 and 10 pr07 flow intermittently with the increasing tip of the current pulse. The current in the choke of the DLC filter 13 has a triangular shape. Thus, the average current value is limited at a certain level, i.e. There is no overcurrent in the power circuit during start-up mode or over-current mode.

If the monitored voltage is equal to or lower than the reference voltage of the control unit 14, the key element 8 is always in the open state and through it constant current flows. In this case, the control unit 14 generates two symmetrical antiphase signals such as a square wave, and current switches of equal duration pass through the keys 9 and 10. The keys 9 and 10 have an on time much longer than the off time. In connection with this, there are times when one key (9 or 10) has not yet been closed, and another key (10 or 9) has already been opened, i.e. both keys are open. It can be stated that the processes in keys 9 and 10 occur with a smooth redistribution of current and with zero voltage.

Galvanic reconnaissance of signal and power circuits predetermines high operational reliability of the device, and the absence of a resistive current sensor in it — lower power consumption.

Claims (1)

Invention Formula A device for protecting electronic equipment, mainly secondary power sources, from inrush currents and overloads, containing a current sensing unit, a key organ and a DLC filter connected in series between the terminals for connecting a primary DC voltage source and a protected electronic equipment, control unit, signal the input of which d is connected to the output of the current reading unit, and the output through the amplifying unit with the control input of the key organ, the auxiliary source DC power, the outputs of which are connected to the power supply inputs of the control unit and the amplifier unit, so that, in order to increase the reliability of operation and efficiency, the current reading units are made in the form of two current transformers and an auxiliary rectifier and filtering unit, a key organ in the form of two keys and two pulse transformers and a control unit and an amplifying unit are two-phase, with the primary windings of current transformers connected in series with the corresponding keys to form two parallel power branches the circuits, and the secondary windings are connected to the input of the auxiliary rectification and filtration unit, the output of which is used as an output of the current reading unit, the primary windings of the pulsed trans shaper - make up the phases of the control input of the key organ, and the secondary windings are connected to the control circuits of the corresponding keys. one