JPH0241632A - Multiplexed power system - Google Patents

Abstract

PURPOSE:To prevent the reverse current of currents from the load side at the time of the generation of the trouble of a secondary-side circuit part without consuming wasteful power by opening a secondary side circuit and blocking the reverse current of currents when the reverse current of currents is detected. CONSTITUTION:When either of the rectifier diodes D1, D2 and capacitor C2 of a secondary side circuit is short-circuited in a first switching power unit 400, potential at a point A is made higher than a point B. Consequently, a 'Hi' level signal is output from an operating amplifier 17, and a 'Hi' level signal is output from an OR circuit 19. An output from the OR circuit 19 turns a transistor 22 ON, charges stored in a capacitor C3 flow through fuses F1, F2 as sudden currents through the transistor 22, and the fuses F1, F2 are cut. A micro-computer 30 stops a switching transistor 13 as well as the first switching power unit 400.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a stabilized power supply device, and particularly to a multiplex power supply system configured by combining a plurality of stabilized power supply devices.

(Prior art) In recent years, in order to keep the operation of stabilized power supplies more stable, two or more sets of stabilized power supplies with the same configuration have been combined to supply output current to a common load. Multiplexed power supply systems are becoming widespread.

Generally, this multiplex power supply system is configured as follows.

FIG. 3 is a diagram showing the configuration of this multiplex power supply system.

In the figure, ]00 is the first switching power supply device,
200 is a second switching power supply device, and 300 is a controller that performs switching control of each switching power supply device 100, 200, etc.

The first switching power supply device '1.00 and the second switching power supply device 200 have the same structure.

In each switching power supply device 100, 200, 1 is a filter, 2 is a rectifier circuit, R1 is a smoothing capacitor, 3 is a switching transistor, 4 is a transformer, 5 is a snubber circuit, and 6 is a control for controlling the switching operation of transistor 4. In the circuit, R1 is a resistor connected to the emitter side of the switching transistor 3.

Further, D1 to D6 are rectifier diodes connected to the secondary side of the transformer 4, and among these, D3 and D6 are for preventing reverse flow of current from the load side.

Furthermore, LL, R2, C2, and C3 are choke coils and smoothing capacitors that constitute a smoothing circuit for compressing ripples in the input current, and 7.8 is a choke coil and a smoothing capacitor that constitute a smoothing circuit for compressing ripples in the input current. Insulating photocoupler R for taking out the voltage of the output section and outputting it to the control circuit 6
3 and R4 are resistances on the load side.

Next, the operation of this multiplex power supply system will be explained.

In normal operation, the first and second switching power supplies 100, 200 perform the same operation as follows.

First, when a commercial AC 100V power source is applied to the input section of each switching power supply device 100, 200, the current is inputted to the rectifier circuit 2 via the filter 1 and full-wave rectification is performed. As a result, a charge corresponding to approximately 140V is accumulated in the smoothing capacitor C1.

When sufficient charge is accumulated in the smoothing capacitor CI, the control circuit 6 starts the switching operation of the switching transistor 3.

When the switching transistor 3 is in the ON state,
The electric charge accumulated in the smoothing capacitor CI flows as a current in the primary coil of the transformer 4, and as a result, a current flows in each secondary coil of the transformer 4 in the direction of conducting the rectifier diodes D1 and D4.

Furthermore, when the switching transistor 3 is in the OFF state, the energy stored in the primary coil is consumed by the snubber circuit 5, so that a current flows in the secondary coil in the direction of conducting the rectifier diodes D2 and D5.

This allows current to flow continuously through each secondary circuit.

After this, the ripple of the current flowing through each secondary circuit is reduced to choke coils Ll, R2 and smoothing capacitors C2, C3.
The constant voltage obtained by this is applied to the load.

On the other hand, the constant voltage obtained in each secondary side circuit is taken out from the at side of the backflow prevention diodes D3 and D6, respectively, and sent to the control circuit 6 via the insulating photo coupler 7.8.

The control circuit 6 controls the switching transistor 3 based on the voltage fed back from each secondary circuit so that the voltage applied to the load from each secondary circuit is always constant.
Controls the pulse-on width to be output to the base of the

If some abnormality occurs and the voltage sent from the secondary circuit becomes higher than the preset value (
For example, +5V is +7■, +12■ is +15V) or becomes low (for example, +5V is +4.2V, +1
．． 2V is +lO, 5V), a signal to that effect is output from the control circuit 6 to the controller 300.

Upon receiving this signal, the controller 300 sends a power OFF signal to the control circuit 6 of the first switching power supply 100 to stop the operation of the first switching power supply 100 and only operate the second switching power supply 200. continue.

By the way, in this multiplexed power supply system, even if the first switching power supply 100 stops operating and only the second switching power supply 200 continues to operate, no current flows from the load side to the first switching power supply 100. The backflow can be prevented by backflow prevention diodes D3 and D6.

In addition, rectifier diodes D1, D2, D4, D5 and capacitors C2, C in the first switching power supply device 100
Even if any of 3 is short-circuited, the output voltage will drop at point a and 0, but the backflow prevention diodes D3 and D
6, the operation of the second switching power supply device 200 is not affected. The same applies to the opposite case.

However, as mentioned above, in conventional multiplex power supply systems, it is essential to use backflow prevention diodes to ensure normal operation in the event of failure of secondary circuit components; The diode is
For example, this results in a voltage drop of about 0.6 ■ for an output voltage of +5 ■, which requires an extra amount of power and causes the problem that the voltage applied to the load is likely to fluctuate. Ta.

(Problem to be solved by the invention) As described above, in conventional multiplex power supply systems, a backflow prevention diode is essential as part of the configuration in order to prevent the backflow of current from the load side to the secondary side circuit. However, this backflow prevention diode consumes a large amount of extra power, resulting in poor efficiency.

The present invention is intended to solve the above-mentioned problems in the conventional multiplex power supply system, and prevents the reverse flow of current from the load side when a failure occurs in the secondary side circuit components without wasting power. The aim is to provide a multiplexed power supply system that can

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above-mentioned object, the multiplex power supply system of the present invention has a primary side circuit and a secondary side circuit with a transformer in between, and the primary side Equipped with multiple stabilized power supplies that obtain stabilized direct current in the secondary circuit from the current in the circuit and supply this to the load, and each of these stabilized power supplies can supply direct current to a common load. In a multiplexed power supply system constructed by multiplexing, there is a detection means for detecting the reverse flow of current from the load side to the secondary circuit, and a detection means that opens the secondary circuit when the reverse flow of current is detected by this detection means. The device is equipped with a backflow blocking means for blocking the backflow of current to the secondary side circuit of the lever.

(Function) In the multiplex power supply system of the present invention, when a reverse current flow is detected by the detection means, the reverse current blocking means opens the secondary circuit to prevent the reverse current flow, thereby saving wasted power. It is possible to prevent current backflow from the load side when a failure occurs in a secondary side circuit component without wasting any time.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 is a circuit diagram showing the configuration of a multiplex power supply system according to an embodiment of the present invention.

In the figure, 400 is a first switching power supply device;
500 is a second switching power supply device, and each of these switching power supply devices 400 and 500 has the same structure.

That is, in each switching power supply device 400, 500,] 1 is a filter, 12 is a rectifier circuit that rectifies the commercial AC 100V that has passed through filter 1, C1 is a smoothing capacitor that stores the rectified charge, 13 is a switching transistor, and 14 is a A single-input multiple-output transformer, 15 is a transformer 14 when the switching transistor 13 is OFF.
A snubber circuit 16 consumes the energy stored in the primary coil, and a control circuit 16 controls the pulse-on width of the switching transistor 13 and stops the operation when an abnormality occurs.

Further, R1 is a resistor connected to the emitter side of the switching transistor 13, D1 to D4 are rectifier diodes connected to the secondary side of the transformer 4, and Ll, R2, C2, and C3 are the secondary coils of the transformer 14. The choke coil and smoothing capacitors R2 and R3, which constitute a smoothing circuit for compressing the generated current ripple, are resistances necessary to detect reverse flow of current from the load side to the secondary side circuit.

Furthermore], 7.18 is the resistance R on the +5v output side, respectively
Compare the potentials of point A and point B across 2, and point D and point 6 across resistor R3 on the +12V output side, and if point A and point 6 on the load side are high, the "HiJ level" A differential amplifier is a backflow detection means that outputs a signal, one is an OR circuit that takes the logical sum of the signals output from each differential amplifier 17 and 18, and 20 is a +5V while insulating the primary side and the secondary side. The voltage obtained at the output section is sent to the A/D of the control circuit 16.
The first insulating photocoupler 21 for sending to the converter (described later) performs an OR operation while insulating the primary side and the secondary side.
This is a second insulating photocoupler for sending an output signal from one circuit to the control circuit 16.

Furthermore, FI and F2 are fuses inserted in the +5V and +12V secondary circuits, respectively, and D5, R6, C4 and 22 are the fuses F1 and F2 that are suddenly connected to each other based on the signals output from the OR circuit 19, respectively. These are rectifier diodes, resistors, capacitors, and transistors that make up the circuit that disconnects these by supplying a current.

Note that R4 and R5 are resistances on the load side, respectively.

Next, the configuration of the control circuit 16 described above will be explained.

30 is a microcomputer that centrally controls the control circuit] 6; 31 is a ROM that stores control programs executed by the microcomputer 30; 32 is a RAM used as a work area for the microcomputer 30; and 33 is a An A/D converter 34 converts the voltage at point E on the emitter side of the switching transistor 13 and the output voltage from the first insulating photocoupler 20 into an 8-bit digital converter. 33
The first 8 holds the digital data output from
It is a bit register.

Further, 35 is a driver that outputs a driving pulse to the base of the switching transistor 13, and 36 is this control circuit 1.
an interface driver for transmitting output data from 6 to the control circuit 16 of the other switching power supply;
37 is an interface receiver that receives the output from the control circuit 16 of the other SWITCHING power supply;
38 is a light emitting diode for notifying the occurrence of an abnormality by blinking light, and 39 is a second 8-bit register in which various human output signals are held.

The 0th bit of this second 8-bit register 39 contains either the signal to be sent from the interface driver 36 or the
Each bit holds a signal received at the interface receiver 37. Further, the second bit holds a signal output to the light emitting diode 38, and the fourth bit holds a signal output to the driver 35.

Furthermore, the signal output from the OR circuit 19 via the second insulating photocoupler 21 is held in the seventh bit.

Next, the operation of the multiplex power supply system configured as above will be explained.

First, when a commercial AC 100V power source is applied to the input section of each switching power supply device 400, 500, the current is inputted to the rectifier circuit 12 via the filter 11, where it is full-wave rectified and applied to the smoothing capacitor CI to approximately 140V. The charge against is accumulated.

Here, the control circuit 6 starts a switching operation in the switching transistor 1B.

When this switching transistor] 3 is ON, the charge accumulated in the smoothing capacitor C1 flows as a current to the primary coil of the transformer 14, and as a result, the rectifier diode D1,
A current flows in a direction that makes D3 and D5 conductive.

Furthermore, when the switching transistor [3] is in the OFF state, the energy stored in the primary coil is consumed by the snubber circuit 15, so that a current flows in the secondary coil in a direction that makes the rectifier diodes D2 and D4 conductive.

This causes a continuous current to flow through each secondary circuit.

After this, the current flowing through each secondary circuit is transferred to the choke coils LL and R2 and the smoothing capacitors C2 and C.
The voltage is compressed in a smoothing circuit composed of 3, and a constant voltage is thereby applied to the load.

On the other hand, the voltage generated in the secondary circuit on the +5V side is sent to the A/D converter 33 of the control circuit 16 via the first insulating photocoupler 20.

The A/D converter 33 converts the input voltage into 8-pixel digital data.

The converted data is held in the first 8-bit register 34.

Thereafter, the microcomputer 30 generates a second 8-bit register based on the data held in the first 8-bit register 34.
The signal set in the fourth bit of the bit register 39 is controlled, and the pulse-on width outputted to the base of the switching transistor 13 via the driver 35 is determined.

As a result, switching control of the switching transistor 13 is performed in response to fluctuations in the voltage obtained in the secondary circuit.

If, due to some abnormality, the voltage generated in the +5V secondary circuit becomes higher than the preset value (for example, +5■ or +7■, +12■ or +15■) or lower (for example, + 5 ■ or +4.2V.

+12■ or +1.0.5V), microcomputer 3
0 stops the operation of its own switching power supply and continues operation only in the other switching power supply.

Next, the operation when any of the rectifier diodes D1, D2 and capacitor C2 of the secondary circuit in the first switching power supply device 400 is short-circuited will be described.

In this case, the potential at point B in the secondary circuit drops rapidly, and the potential at point A on the load side across resistor R2 becomes higher than point B.

As a result, the operational amplifier 17 outputs an l''HiJ level signal, and the OR circuit 19 outputs an rHiJ level signal.

The signal from the OR circuit 19 is transmitted to the second 8-pin in the control circuit 16 via the second insulating photocoupler 21.
- Set to the 7th bit of register 39.

On the other hand, the output of the OR circuit 9 is simultaneously input to the base of the transistor 22 in the fuse cutting circuit.

As a result, the transistor 22 is turned ON, and current is supplied from the secondary coil of the transformer 14 via the rectifier diode D5 and the resistor R4, so that the charge accumulated in the capacitor C3 is transferred via the transistor 22. As a result, a sudden current flows through the fuses F1 and F2 of each secondary circuit, thereby cutting off each of the fuses Fl and F2.

At the same time, the microcomputer 30 stops the on-pulse output to the switching transistor 13 to stop the operation of the first switching power supply 400, and also controls the second switching power supply via the interface driver 36.
An instruction is also sent to the switching power supply device 500 to stop its operation.

Note that if the switching transistor 13 is damaged while the secondary side circuit components are not short-circuited, the output voltage to the load will stop, but since each secondary side circuit component is normal, points A and B , or no backflow current occurs between point and point D. Therefore, the differential amplifier 17.
No backflow is detected at 1.8.

However, if an abnormality occurs in the switching transistor 13, no collector current flows during power-on, so the voltage at point E drops.

The voltage at point E is input to the A/D converter 33 and converted into digital data, which is held in the first 8-bit register 34.

When the microcomputer 30 learns from the contents of the first 8-bit register 34 that the voltage at point E has dropped, it learns that an abnormality has occurred and starts the first switching power supply 40.
At the same time, the second bit of the second 8-bit register 39 is set to "0" and the light emitting diode 38 is turned on.

At the same time, the operator is notified by displaying on a display device such as a CRT that the power supply has failed.

Thus, according to the device of this embodiment, due to a component failure in each secondary circuit, the potential on the load side becomes high at both ends of the resistors R2 and R3 inserted at the output end of each secondary circuit. is detected by differential amplifiers 17 and 18, and fuses Fl and F2 of each secondary side circuit are rapidly disconnected based on the result of this detection. It is possible to prevent backflow of current from the load side to each secondary side circuit at the time of occurrence, and it is possible to reduce power consumption and improve reliability.

Next, another embodiment of the present invention will be described.

FIG. 2 is a circuit diagram showing the configuration of a multiplex power supply system according to another embodiment of the present invention.

In the configuration of the apparatus of this embodiment, the same parts as in FIG. 1 are denoted by the same reference numerals, and the explanation of the overlapping parts will be omitted.

In the figure, 41 and 42 are relays, and in this embodiment, these relays 41 and 42 are used in place of the fuses used in the previous embodiment to prevent backflow.

Further, 43 and 44 are inverters connected in series to the output side of the OR circuit 19, R7 and R8 are resistors connected in parallel to the base side of the transistor 22, and 45 is connected to the emitter side of the transistor 22. , a relay magnet coil that switches each relay 41, 42.

The other structures are the same as in FIG. 1.

Next, the operation of preventing backflow using the relays 41 and 42 in this embodiment will be explained.

First, when a current is generated in the secondary coil of the transformer 14, the current flows to the capacitor c3 via the rectifier diode D5 and the resistor R6, and charge is accumulated in the capacitor C3.

After this, when the charge accumulated in capacitor C3 increases,
The base voltage of the transistor 22 also rises due to the voltage division between the resistor R7 and the resistor R8, and finally the l transistor 22 turns on.
becomes.

As a result, the relay magnet coil 45 is driven, each relay 41, 42 is brought into a connected state, and each secondary circuit starts outputting a DC voltage.

Here, the rectifier diode D1. in the secondary side circuit. ．． D
2. If any of the smoothing capacitors c2 becomes short-circuited,
A reverse current flows from point A to point B across resistor R2.

The occurrence of this reverse current is detected in the operational amplifier 17,
As a result, an rHiJ level signal is output from the OR circuit 19.

Thereafter, the signal output from one OR circuit is inverted to the "Lo" level by the inverter 43, so the transistor 22 is turned off.

As a result, the operation of the relay magnet connected to the emitter side of the transistor 22 is also turned off, and each relay 4
1.42 is disconnected from the circuit, thereby preventing backflow.

(According to the multiplex power supply system of this embodiment, when a reverse current occurs from the load side to each secondary circuit, the relays 41 and 42 are disconnected and the secondary circuit is immediately disconnected from the load side.) It is possible to prevent the reverse flow of current to.

Further, according to this embodiment, it is possible to carry out live-line work when replacing a failed power supply device. In this case, replace the power supply with relays 41 and 42 disconnected, start it up, wait until normal values of charge are accumulated in the smoothing capacitors C2 and C3 in each secondary circuit, and then connect the relays. The operating points of 41 and 42 are set so that they close automatically.

This makes it possible to prevent current backflow from the start of operation after replacing the power supply device.

In each of the embodiments described above, two sets of switching power supply devices are multiplexed, but the multiplex power supply system of the present invention is not limited to this, and three or more sets of devices are multiplexed. It may be configured as follows.

Furthermore, the present invention is not limited to the above-mentioned switching power supply device as a power supply device, and the present invention can be similarly applied to, for example, a dropper power supply device or other stabilized power supply device.

[Effects of the Invention] As explained above, according to the multiplex power supply system of the present invention, when a reverse current flow is detected by the detection means, the secondary side circuit is opened to prevent the reverse flow of current. It is possible to prevent current from flowing backward from the load side when a failure occurs in a secondary side circuit component without consuming electric power.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram for explaining the configuration of a multiplex power supply system according to one embodiment of the present invention, and FIG. 2 is a circuit diagram for explaining the configuration of a multiplex power supply system according to another embodiment of the present invention. ,
FIG. 3 is a circuit diagram for explaining the configuration of a conventional multiplex power supply system. ]4...Transformer, ]6...Control circuit, 17.18...
operational amplifier, 19...OR circuit, 22...l transistor for fuse disconnection, 400...first switching power supply device, 500...second switching power supply device,
Ft, F2... fuyuse. Applicant: Toshiba Corporation

Claims (1)

[Claims] (1) Stabilization that has a primary side circuit and a secondary side circuit that sandwich a transformer transformer, obtains stabilized direct current in the secondary side circuit from the input current in the primary side circuit, and supplies this to the load. In a multiplex power supply system comprising a plurality of power supply devices, each of which is configured to multiplex the stabilized power supply devices so that they can supply the DC to a common load, current from the load side to the secondary circuit and a backflow prevention means for opening the secondary circuit and blocking the backflow of the current when the detection means detects the backflow of the current. power supply system.