SU1124399A1 - Device for providing dual facilities for device for supplying d.c.power to load - Google Patents

Abstract

A DC LOADING POWER SUPPLY DEVICE, containing the main AC source, connected through the first transformer to the first rectifier group, a backup DC source, the output of which is through the series-connected DC / AC converter and the second transformer podkkl to the second group the rectifiers connected to the corresponding output of the device and the corresponding first rectifier of the group, and the startup unit consisting of the first transistor switch a and a control input through a third rectifier with a first transformer, characterized in that, in order to increase the reliability of the device, a constant voltage source, the first operational amplifier, the second transistor switch, the time setting capacitor limiting diode, second operational amplifier, six scaling resistors, three current-limiting resistors and two feedback resistors, each of which is connected to the output of the corresponding operating about the amplifier, and another output to the direct input of this operational amplifier; the direct inputs of the first and second operational amplifiers, respectively, through the first and second scaling resistors are connected to a common bus connected to the first terminal of the time of the driving capacitor, the emitter of the second transistor switch, the cathode of the limiting diode, the common point of the constant voltage source, and. the negative output of the third rectifier, the control input of the start-up unit through the third scaling resistor is connected to the inverting input of the first operational amplifier and through the fourth scaling resistor to the negative output (of the constant reference voltage source, the output of the first operational amplifier is connected through the first current-limiting resistor to the anode of the limiting diode and the base of the second transistor switch, the collector of which is connected to the second terminal the time of the driving capacitor and h cut the second current-limiting resistor to the negative output of a constant voltage source, and after the fifth I scale:, o; the common resistor - to the inverting input of the second operational amplifier connected to the positive terminal of a constant reference voltage source, the output of the second operational amplifier through the third current-limiting resistor is connected to the base of the first transistor switch, to the collector of which the control input of the dc to ac converter is connected, and Ttero is the negative output of the backup DC source.

Description

The invention relates to electrical engineering and can be used to ensure reliable power supply of automatic and instrumentation devices whose power supply breaks are unacceptable.

A device for supplying a DC load is known, containing a primary AC source and a backup DC source connected to the load via rectifying elements, with a converter connected between the back-up DC source and rectifying elements the number of loads fed ij.

However, the converter operates continuously, including while the load is powered from the main source, as a result, the efficiency of the entire device decreases and the backup source (battery) energy is wasted.

It is also known a device containing a primary AC source, connected via a first transformer, to a group of first rectifiers, a backup DC source, the output of which through serially connected DC / AC converter and a second transformer is connected to a group of second rectifiers connected with the corresponding output of the device and the corresponding first rectifier, and the start-up unit, consisting of a series-connected resistor, transformer winding and a transistor switch, whose input is connected to a separate winding of the first transformer via an additional rectifier. When the main AC source is disconnected, the converter starts up and the load starts to be powered from the backup source. If the main source is working normally, then the converter is turned off, which increases its reliability and efficiency 2.

However, when the HQBHoro source voltage is reduced to the limit of the allowable level, the converter does not start up exactly and occurs with a large variation in the voltage deviation of the main source, and at the unlocking point of the starting transistor switch it is possible to randomly turn on and off the backup source that causes large voltage ripples on the load and may cause its abnormal operation.

The purpose of the invention is improving the reliability of the device.

The goal is achieved by the fact that, in a device for reserving the power supply of a direct current, containing the main source of alternating current, connected through the first transformer to the group of first dischargers, a backup source of direct current, the output of which is connected in series with the direct current converter to the alternating and second transformer is connected to a group of second rectifiers connected with the corresponding output of the device and the corresponding first rectifier of the group, and the start-up unit, with consisting of a first transistor switch and connected by a control input through a third rectifier to a first transformer, a DC voltage source, a first operational amplifier, a second transistor switch, a time setting capacitor, a limiting diode, a second operational amplifier, There are three scaling resistors, three current-limiting resistors and two feedback resistors, each of which is connected by one output to the output of the corresponding operational amplifier, and the other output m - to the direct input of this operational amplifier, the direct inputs of the first and second operational amplifiers, respectively, through the first and second scaling resistors are connected to a common bus connected to the first terminal, the time of the driving capacitor, the emitter of the second transistor switch, the cathode of the limiting diode, the common source point a constant reference voltage and a negative output of the third rectifier that controls the input of the start-up unit through the third. the scaling resistor is connected to the inverting input of the first operational amplifier and through the fourths the scaling resistor to the negative output of a constant reference voltage source, the output of the first operational amplifier connected the first limiting resistor to the anode of the limiting diode and the base of the second transistor switch, the collector of which is connected to the second output of the time setting of the capacitor and through the second current-limiting resistor to the negative terminal of the constant-voltage source And the fifth scaling resistor to the inverter of the second operational amplifier, connected to the positive terminal of the constant voltage source, is output the second. Rogo operational amplifier third current limiting resistor

connected to the base of the first transistor switch, to the collector of which the control input of the dc to ac converter is connected, and to the emitter - the negative output of the backup dc source.

Figure 1 shows the scheme of the proposed device; 2 a timing diagram of the operation of its individual elements.

A device for reserving a DC power supply contains a primary source 1 of alternating current, a first transformer 2, first rectifiers 3, a backup source 4 of direct current, a converter 5, a second transformer 6, second rectifiers 7, outputs 8 of the device, start block 9 , first transistor switch 10, third rectifier 11, constant voltage source 12, first operational amplifier 13, second transistor switch 14, time specifying a capacitor 15, limiting diode 16 second operational amplifier 17, wt stacking resistors 18, current limiting resistors 19, feedback resistors 20, Zener diode 21 resistors 22, a communication transformer 23, and transistors 24.

In FIG. 2, U „j is the voltage of the primary AC source, applied after the rectifier 11 to the scaling resistor 18, UQ is the voltage of the constant voltage source 12, applied to the scaling resistor IS; U (- total voltage at the inverting input of the first operational amplifier 13, and 2 - voltage at the output of the first operational amplifier 13; DC - voltage for a time of the master capacitor 15; At the voltage at the inverting output of the second operational amplifier 17; control voltage the io is the initial moment of time, i is the beginning of the voltage reduction of the main source with the tolerance output; i2 the converter starts; ij is the time of the voltage recovery of the primary source; i4 the turn-off time of the transistor azovatel.

The device works as follows.

"

In case the effective value of the voltage in the AC network is within the permissible limits, for example, not lower than 187 V, the amplitude of the rectified sinusoidal voltage supplied to the input of the controller of the starting of the starting of the apparator exceeds the level of the direct voltage supplied

from the reference source 12, while the output of block 9 does not include a starting signal for converter 5, the converter is turned off, and voltages from the outputs of rectifiers 3 supplied from the AC mains 1 are supplied to the common power supply line 8 of the device.

With a short-term or long-term decrease in the supply voltage of the alternating current network for the established rate, the amplitude of the voltage supplied to the input of the unit 9 from the source 1 becomes less than the voltage level supplied from the reference source 12, while the output

5 of block 9, a converter start signal appears, converter 5 starts operating, and converted voltages from a backup direct current network 4 (for example, a battery) enter the power supply line. In block 9 of starting the converter, the first and second null organs are assembled at the first and second operational amplifiers 13 and 17, the signal of the first null organ, respectively, is fed to the control input of the transistor switch 14, the charge and discharge control time of the master capacitor 15 signal with

0 which is supplied to the second null organ (second operational amplifier 17) controlling the first transistor switch 10, which starts or stops the converter 5.

5 In order to create a key operation mode, the amplifiers 13 and 17 are covered by positive feedback through resistors 20. The Zener diodes 21 and the resistor 22 form a constant voltage source 12. The diode 16 fixes a positive voltage at the input of the key 14. In the interval t - (Fig. 2), the effective value-voltage of the AC mains is exceeded by the lower acceptable limit,

5, for example, 187 V, with the amplitude of the rectified sinusoidal voltage and "(rectifier 11 exceeds the reference voltage level of the RR, in each half-period the zero-body is switched 13. At negative values Uo, key 14 is open, voltage VUS the capacitor 15 is equal to 0. In the interval 1 -ij, the voltage at the input of the zero-body 17 is positive, and at its output is negative, while the switch 10 and, accordingly, the starting circuit of the DC voltage converter 5 are open.

0 of the half period following time i, the effective value of the AC supply voltage falls below the set limit, while the voltage amplitude U c does not reach the level QO f voltage Ut at the input of the zero-body 13 remains negative, and the output is positive, the key 14 is closed, the capacitor 15 is charged, the voltage Up on it increases and tends to the maximum negative value. Accordingly, the voltage U) at the input of the null organ 17 decreases, at time 12 a zero value is reached and further becomes negative. At time tj, the voltage at the output of the zero-body 17 is changed to positive, key 10 opens and starts converter 5. At the beginning of the half-cycle following the moment ij, the effective value of the network voltage rises to the set norm and at time i the key 10 opens. The converter is turned off and then all the processes occur the same as in the interval (-to -ii). The proposed scheme has a high speed. With an appropriate choice of the constant charging and discharging time of the capacitor 15, the on and off times of the converter after. going beyond the tolerance or returning to the normal voltage of the AC mains does not exceed the duration of one half period. Thus, the converter is reliably started not only when the main source is completely turned off, but also when its voltage decreases beyond the permissible limit, and after the normal power is restored, the main source is disconnected, which increases its reliability and saves the electrical energy of the backup source .

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Claims (1)

DEVICE FOR RESERVING DC LOADING POWER SUPPLIES, containing the main AC source connected through the first transformer to the group of first rectifiers, a backup DC source, the output of which is connected through a series-connected DC / AC converter and the second transformer to the group of second rectifiers connected to the corresponding the output of the device and the corresponding first rectifier of the group, and the start-up unit, consisting of the first transistor switch and the connection the control input through a third rectifier with a first transformer, characterized in that, in order to increase the reliability of the device, a constant reference voltage source, a first operational amplifier, a second transistor switch, a timing capacitor, limiting a diode, a second operational amplifier, six scaling resistors, three current-limiting resistors and two feedback resistors, each of which is connected with one output to the output of the corresponding operational amplifier, etc. The other conclusion is to the direct input of this operational amplifier, the direct inputs of the first and second operational amplifiers, respectively, through the first. The second and second scaling resistors are connected to a common bus connected to the first output of the time-setting capacitor, the emitter of the second transistor switch, the cathode of the limiting diode, and the common point of the constant reference voltage source and. to the negative terminal of the third rectifier, the control input of the launcher through the third scaling resistor is connected to the inverting input of the first operational amplifier and through the fourth scaling resistor to the negative terminal of the constant reference voltage source, the output of the first operational amplifier is connected through the first current-limiting resistor to the anode of the limiting diode and the base the second transistor switch, the collector of which is connected to the second output of the timing capacitor and through the second current-limiting resistor to the negative terminal of the constant reference voltage source, and through the fifth scaling resistor to the inverting input of the second operational amplifier connected to the positive terminal of the constant reference voltage source, the output of the second operational amplifier through the third current-limiting resistor is connected to the base of the first transistor switch, to the collector of which the control input of the DC / AC converter is connected, and the negative terminal is connected to the emitter backup DC source.