RU2123225C1 - Shipboard equipment power supply - Google Patents

Abstract

FIELD: electrical engineering; power supply to shipboard automatic-control and communication equipment. SUBSTANCE: power supply operating into load incorporating input rectifier with capacitive ripple filter has series-connected rectifier 1 and inverter 2, as well as protective and switching unit incorporating current-limiting resistor 3 with parallel- connected contacts of first controlled switch 4 and voltage sensor connected to output of inverter 2; newly introduced in power supply is second control switch 5 whose make contacts are connected to load 6 and to current-limiting resistor 3 which is connected in series with output of inverter 2. Voltage sensor is built up of series-connected diode 7, resistor 8, and light-emitting diode of first optocoupler 9 incorporated in protective and switching unit and having emitter of its photodetector connected through ripple filter 11 to resistor 12 of time-setting RC circuit whose common point is connected to first threshold unit 15 whose output is connected through NOT gate 19 to cathode of light-emitting diode of second optocoupler 20 and also to capacitor 25 of second time-setting RC circuit whose common point is connected through second threshold unit 27 to cathode of light-emitting diode of third optocoupler 30. Coils of first and second controlled switches 4, 5 are connected in series with collector circuits of photodetectors of second and third optocouplers 20, 30, respectively; second coil leads of controlled switches 4, 5, anodes of light-emitting diodes of second and third optocouplers 20, 30, and collector of first optocoupler 9 are connected to positive terminal of rectifier 1 while emitters of second and third optocouplers 20, 30, lead of resistor 26 of second time-setting RC circuit, and second plate of capacitor 13 of first time-setting RC circuit, to its negative terminal. EFFECT: improved reliability due to stepped circuit arrangement for load connection. 2 cl, 1 dwg

Description

 The invention relates to electrical engineering and can be used to power ship automation equipment and communications, mainly equipment equipped with an input rectifier with a smoothing capacitive filter.

 A power supply device [1] is known with combined protection of a voltage converter, comprising a converter control unit, a load, a current sensor, a transient limiting resistor connected in series with it, a parallel circuit of a resistor and an optocoupler LED, a photodetector of which is included in an additional power supply circuit, a capacitor delays connected in parallel with the optocoupler LED. as well as a scheme for generating the duration of the amplitude of the control pulses and the frequency control unit of the converter, built on shift registers and triggers.

 The disadvantage of this device is its complexity and the use of an additional power source in the drive control unit.

 It is also known a device [2] for protecting a load power source, which incorporates an input capacitive filter. The device uses a single-winding relay, the winding of which is connected between the base of the transistor and the output of the threshold element, and an RC circuit that shunts the relay winding and ensures, on the one hand, the transistor current is constant, and on the other, protects the output circuits of the threshold element from overvoltage. The charge of the load capacitance is provided through the circuit: the positive output of the power source - saturated transistor - current limiting resistor - load - negative output of the power source. When the threshold voltage is removed, the current through the relay winding stops, and its contacts open, disconnecting the load from the power source.

 The disadvantage of this device is the use of a transistor circuit withstanding relatively low overloads in a shunt-limiting resistor.

 As a prototype of the invention, a power supply [3] is adopted, comprising a rectifier connected in series with a capacitive smoothing filter at the output, an inverter and a load connected to the secondary winding of the inverter output transformer. The protection node, providing a smooth inclusion of the device, contains a current-limiting resistor shunted by a thyristor key, and a voltage sensor made in the form of a secondary auxiliary winding of the inverter output transformer. At the end of the charge of the capacitance of the smoothing filter of the rectifier, a control signal is supplied to the inverter keys through a current-limiting resistor, and a voltage appears in its secondary winding, which is rectified by diodes, smoothed by the RC filter and fed to the thyristor control electrode. The thyristor is unlocked by shunting the current-limiting resistor, and remains in this position as long as the inverter is operating.

 The disadvantage of this device is the probability of self-unlocking of the thyristor switch due to the high voltage speed of the anode-cathode when the mains voltage is turned on. In addition, the device does not provide protection of the power source from charging extracurrents of the load, which has a rectifier with a capacitive filter at the input.

 The objective of the invention is to increase the reliability of the power supply device when operating on a load containing an input rectifier with a capacitive smoothing filter and requiring connection for normal operation at rated input voltage and current.

 To solve this problem, a power supply device for the ship’s equipment, containing a rectifier and an inverter connected in series, as well as a protection and switching unit, including a current-limiting resistor with parallel connected contacts of the first controlled key, and a voltage sensor connected to the inverter output, enter a second controlled key that closes whose contacts are connected to the load and a current-limiting resistor, which is connected in series to the inverter output. The voltage sensor is made in the form of a series-connected diode, resistor and LED of the first optocoupler of the protection and switching unit, whose photodetector emitter is connected through a smoothing filter to the resistor of the first RC timing circuit, the common point of which is connected to the first threshold block, the output of which through the element is NOT connected to to the cathode of the LED of the second optocoupler, as well as to the capacitor of the second timing RC circuit, the common point of which is connected through the second threshold block to the cathode of the LED of the third optocoupler, to the collector The photodetector chains of the second and third optocouplers are connected in series with the windings of the first and second controlled keys, respectively, while the second ends of the controlled key windings, the anodes of the LEDs of the second and third optocouplers and the collector of the first optocoupler are connected to the positive terminal of the rectifier, and the emitters of the second and third optocouplers the second timing RC circuit and the second capacitor lining of the first timing RC circuit to its negative terminal.

 In this case, the first threshold block is made in the form of two series-connected elements NOT covered by a positive current feedback circuit from a diode and a resistor.

 The invention is illustrated by a drawing of the electrical circuit of the device.

 The power supply device for the ship’s equipment contains a rectifier 1 connected in series to the secondary winding of an input transformer (not shown) of an alternating current network ≈ 220 V, 400 Hz, an inverter 2, a current-limiting resistor 3 with parallel contacts 4 of the first controlled key, contacts 5 of the second managed key and a load 6 operating from an input AC voltage of ≈ 220 V, 50 Hz and equipped with an input rectifier with a smoothing capacitive filter.

 Rectifier 1 can be implemented according to the well-known scheme of the diode bridge with a capacitive filter [3, Sec. 2.1] and provides a constant voltage of ± 12 V at the output. Inverter 2 converts the input DC voltage into a rectangular variable ≈ 220 V, 50 Hz and can be implemented according to the inverter bridge circuit with high-power transistors, regulated by the pulse-width modulation method [3 , sec. 2.3].

 An output voltage sensor is also connected to the output of inverter 2, made in the form of a series-connected diode 7, a resistor 8, and an LED of the first optocoupler 9 of the protection and switching unit, powered by the output terminals of the rectifier 1. The photodetector of the first optocouple 9, whose collector is connected to +12 In rectifier 1, and the base is connected to the emitter through a resistor 10, it is connected by the emitter through a smoothing RC filter 11 to the resistor 12 of the first RC timing circuit, the common connection point of which with the capacitor 13 is connected through rubber side 14 to the first threshold block 15, made in the form of two series-connected elements HE 16 and 17, covered by a positive feedback circuit 18, consisting of a diode and a resistor. The output of the threshold block 15 through the element 19 is connected to the cathode of the LED of the second optocoupler 20, the anode of which is connected through the resistor 21 to the +12 V terminal of the rectifier 1. In the collector circuit of the photodetector of the optocoupler 20, the base of which is connected to the emitter through the resistor 22, a winding 23 the first managed key, shunted by diode 24 and connected by the second end to the +12 V terminal of rectifier 1. The capacitor 25 of the second RC timing circuit is also connected to the output of the first threshold block 15, the connection point of which is with the resistor 2 6 is connected to the input of the second threshold unit 27 from two series-connected elements NOT 28 and 29. The output of the threshold unit 27 is connected to the cathode of the LED of the third optocoupler 30, the anode of which is connected through the resistor 31 to the +12 V terminal of rectifier 1. To the collector circuit of the photodetector of the optocoupler 30 the winding 32 of the second managed key is turned on, shunted by the diode 33 and connected to the +12 V terminal of the rectifier 1 similarly to the winding 23 of the first managed key. The base of the photodetector of the optocoupler 30 is connected to the emitter through a resistor 34. The emitters of the optocouplers 20 and 30, the second output of the resistor 26 of the second timing RC circuit, the second lining of the capacitor 13 of the first timing circuit and the smoothing filter capacitor 11 are connected to the -12 V terminal of the rectifier 1.

 The device operates as follows.

 After connecting the device to the network, the rectified and filtered DC voltage of ± 12 V of rectifier 1 is supplied to the inputs of inverter 2 and to the power of the protection and switching unit of the device. The supply of a positive potential to the anode of the LED of the optocoupler 30 at a negative potential of the cathode excites light emission of the LED, as a result of which the photodetector transistor of the optocoupler 30 opens, and current flows through the winding 32 of the second controlled key, closing its contacts 5 and providing a supply voltage to the load 6 from the inverter 2 through a current-limiting resistor 3. After the appearance of an inverter 2 (and, accordingly, in the voltage sensor circuit 7 - 8 - 9) at the output of the alternating voltage, the opto-optic LED turns on 9, as a result of which a pulsating current appears in the emitter circuit of the optocoupler transistor 9, which is smoothed by the filter 11 and starts charging the capacitor 13 of the first RC timing circuit, the time constant (RC = 3-5 s) of which is determined by the charge time of the capacitive load filter 6. At the end of the charge time of the capacitor 13, a constant positive voltage appears at the output of the threshold block 15, which is inverted by the element HE 19, and a negative potential is applied to the cathode of the LED of the optocoupler 20, exciting the LED radiation. A current starts flowing through the winding 23 of the first controlled key along the photodetector 20 circuit of the optocoupler, and the key contacts 4 are closed by shunting the current-limiting resistor 3. The introduction of the positive feedback circuit 18 into the threshold block 15 allows eliminating the "chatter" of the key contacts and ensuring a reliable connection of the load supply circuit . After the positive voltage appears at the output of the threshold block 15, the charging current flows through the capacitor 25 of the second RC timing circuit (time constant RC = 350 - 400 ms), during which the winding 32 of the second controlled key is momentarily disconnected and its contacts 5 open. at the end of the charge of the capacitance 25, the light emission of the LED of the optocoupler 30 is resumed, and the contacts 5 of the second controlled key are closed again.

 The proposed two-stage load connection circuit provides, at the first stage, protection of the inverter from charging extracurrents of the capacitive load filter and its smooth operation, and at the second stage, connection of load nodes at the rated input voltage and load current, which is necessary for the normal functioning of the equipment.

 The industrial applicability of the invention is determined by the fact that the proposed device can be manufactured according to the description and drawing of the electrical circuit using commercially available components according to known technology and can be used as a secondary power source for equipment for various purposes, having an input rectifier with a capacitive filter.

Bibliography
1. RF patent N 2011261, cl. H 02 H 7/12, 04/15/94.

 2. USSR copyright certificate N 1707688, cl. H 02 H 7/12, 01/23/92.

 3. Bass A.A., Milovzorov V.P., Musolin A.K. Secondary power supplies with transformerless input. - M .: Radio and communications, 1987, p. 30, (prototype).

Claims (2)

 1. The power supply device of the ship's equipment, containing a rectifier and an inverter connected in series, as well as a protection and switching unit, including a current-limiting resistor with parallel contacts of the first controlled key, and a voltage sensor connected to the inverter output, characterized in that the second controlled a key whose closing contacts are connected to the load and a current-limiting resistor that is connected in series to the inverter output, the voltage sensor is made in the form of a series-connected diode, resistor and LED of the first optocoupler, the photodetector emitter of which is connected via a smoothing filter to the resistor of the first RC timing circuit, the common point of which is connected to the first threshold unit, the output of which through the element is NOT connected to the cathode of the LED of the second optocoupler, as well as to the capacitor of the second timing RC circuit, the common point of which is connected through the second threshold block to the cathode of the LED of the third optocoupler, to the collector circuit of the photodetectors of the second and third optocouplers the windings of the first and second controlled keys are turned on respectively, while the second ends of the controlled key windings, the anodes of the LEDs of the second and third optocouplers and the collector of the first optocoupler are connected to the positive terminal of the rectifier, and the emitters of the second and third optocouplers, the resistor terminals of the second RC timing circuit and the second capacitor lining of the first timing RC circuit - to its negative terminal.  2. The device according to claim 1, characterized in that the first threshold block is made in the form of two series-connected elements NOT covered by a positive feedback circuit from a diode and a resistor.