SU957193A1 - Direct current supply source - Google Patents

Description

(S) DC POWER SUPPLY

The invention relates to the conversion of electrical energy and can be used in the construction of power sources in onboard networks for converting low voltage direct current to direct current high voltage. . Devices are known that are designed to supply a load with a stabilized voltage, the value of which differs from the value of the supply voltage of a direct current network. The disadvantage of these devices is a relatively low output power of ten watts. The closest in technical essence to the present invention is a DC power supply, which contains an inverter, connected to the input terminals through the opening contacts of the first contactor and the current limiting resistor, in parallel to which are connected the short-circuiting contacts of the second contactor, transformer, the primary winding of which is connected to the inverter's output, and one of the secondary windings through a switch of the transformer windings, a rectifier with a filter — with output terminals, a control unit, an output connected to the inverter's control input, voltage level comparator, input connected to the input terminals, the blocking unit, the first input of which is connected to the low-voltage secondary winding of the transformer, and the output to the control input of the second contactor, the restarting unit and generating the restart signals by the power supply circuit connected to the input terminals, the inputs to the low-voltage secondary winding of the transformer, and the outputs to the inputs of the electronic key, the output of which is connected to the control input of the first contactor G2}.

This device converts the onboard voltage of 27 V to the 3 "V voltage required to power the onboard device. To increase the stability of the output voltage of the comparator, depending on the level of the supply voltage, it issues a command to the transformer winding switch, which connects the required transformer tap to the converter rectifier.

A disadvantage of this device is the possible breakdown of the converter operation at the moment of switching the transformer windings, which reduces the reliability of operation.

The purpose of the invention is to eliminate this drawback.

This goal is achieved by introducing a delay node / connected between the voltage level comparator output and the input of a transformer winding switch, and the OR circuit and time relay connected between the outputs of the comparator and the second input of the blocking node.

The drawing shows a block diagram of a DC power source.

The device contains an inverter 1 connected to the input terminals through the opening contacts 2 of the first contactor 3 and a current-limiting resistor, k, in parallel with which the closing contacts 5 of the second contactor 6 are connected, the transformer 7 the control unit 8, the restart unit 9, the blocking unit 10 connected to the low voltage the secondary winding of the transformer 7 and the contactor 6, the node 11 of forming the restart signals electronic key 12, connected in series rectifier 13, filter, comparator 15 voltage levels, under connected to the switch 16 through the node 17 delay, circuit OR 18 connected to the comparator 15 and through the time relay 19 to the second input of the node 10 of the lock.

The device works as follows.

The supply voltage is supplied through the opening contacts 2 and the current limiting resistance k to the inverter 1 and directly to the control node 8, the node for generating the repeated cycle signals P. The correction power resistance A- serves to limit the current through the thyristors

inverter 1 and ensure reliable startup. In the control unit 8, rectangular thyristor control pulses are generated, which are supplied to the control electrodes. Inverter 1 generates powerful rectangular pulses that are applied to the primary winding of the transformer 7, the voltage of the secondary high-voltage winding of the transformer through the switch 1b is fed to the rectifier 13, filter C, In the event of a breakdown or absence of starting, the restarting node 9 generates pulses controls which pass the key 12, periodically opening for the time of the start-up cycle, the potential from the signal-generating device of the repeated cycle 11, goes to the contactor 3, the last, respectively, periodically disconnects contacts 2 until the voltage appears at the output of the transformer 7. When changing (increasing or decreasing) voltage

the power supply triggers a comparator 15, which issues the appropriate command to the node 17 of the delay and through the circuit OR 18 to the time relay 19, the latter generates and issues a command to the node

10, which takes the voltage off the contactor 6, the contacts 5 open and the inverter 1 begins to flow through the current limiting resistor k, at this time the command from the comparator 15 delayed in the start node 17 for the time required to open the contacts 5 of the contactor 6 enters the switch 16, which connects the desired tap of the transformer winding.

Thus, the switching of the transformer 7 windings by the switch 16 is carried out when the contacts 5 of the contactor 6 are open, which leads to an increase in the reliability of the device at this point in time, since it is powered through the current limiting resistor 7. After switching the transformer windings, which corresponds to the rear to the front of the command from time relay 19, interlock node 10 is activated, and contactor 6 again closes its contacts 5.

Claims (2)

Invention Formula A DC power supply containing an inverter connected the input to the input terminals through the opening contacts of the first contactor and the current-limiting resistor, in parallel with which the closing contacts of the second contactor are connected, the transformer, the primary winding of which is connected to the output of the inverter, and one of the secondary windings through the switch of the transformer windings, the rectifier with filter — with output terminals, control node, output connected to inverter control input, voltage level switch, input connected to input terminals, blocking node, first input which is connected to the low-voltage secondary winding of the transformer, and the output to the control input of the second contactor, the node for restarting and generating the restart signals on the power supply connected to the input terminals, inputs -.0 by the low-voltage secondary winding of the transformer, and outputs to the inputs electronic key whose output connected to the control input of the first contactor, characterized in that in order to increase the reliability of the power source, a delay node is inserted in it connected between the voltage level comparator output and the winding switch input. , a transformer, and a series-connected OR circuit and a time relay connected between the outputs of the comparator and the second input of the blocking node. Sources of information taken into account in the examination 1, Mikhailov E.E. Transistor voltage converters of direct current with the use of pulse-width pulse-frequency modulations to stabilize the output voltage. SRI. - In Sat. Semiconductor devices and electrical equipment. 1972, Vol. 10, s, 205-208. 2. USSR author's certificate ff 130738, “l. H 02 M 7/52, 1965.