JP2001204135A - Redundant operation system for power supply unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain the redundant operation of a power supply unit capable of contribution to downsizing and cost reduction in a load side and prevent generation of discharging from a battery or the like in the redundant operation of the power supply unit using the battery or the like. SOLUTION: An overcurrent detecting circuit 4 for detecting whether or not the current supplied from power supply units 5, 6 to a load is in excess of load side overcurrent is provided at the front stage of the load. The power supply units 5, 6 includes a control circuit for stopping output current from the power supply units 5, 6 when they receive an overcurrent detecting signal outputted from the overcurrent detecting circuit 4. The load side overcurrent value of the power supply unit 6 using a battery BA is set so as to be smaller than that of the power supply unit 5 using an a.c. input AC, and the maximum of the output voltage of the power supply unit 6 is set so as to be smaller than that of the power supply unit 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a redundant power supply operation system in which a plurality of power supply devices are connected in parallel with each other to supply current to a load from the plurality of power supply devices.

[0002]

2. Description of the Related Art Redundant operation of a power supply device according to the prior art is as follows.
When a current is supplied from a plurality of power supply devices to a load, and one of the power supply devices cannot supply the current to the load for some reason, the current supplied to the load by another power supply device is covered. Therefore, the redundant operation system of the power supply devices is a power supply device group having a current supply capability that is excessively larger than a steady load current that can be supplied by one power supply device.

In the redundant operation of the power supply device, during normal operation, current is supplied in order from a power supply device having a higher output voltage. Also, in the redundant operation of the power supply unit, if an abnormality occurs on the load side and an overload current flows,
The overcurrent protection device provided in each power supply device operates. Therefore, in the related art, each power supply device is configured to protect itself against an overload current on the load side.

The prior art will be described in more detail with reference to FIGS. 6 and 7. FIG. FIG. 6 shows two power supply units 1 and 2
FIG. 4 is a diagram illustrating a redundant operation system of a power supply device that supplies a current to a load (not shown) connected to a filter unit F by using the power supply device. As shown, the power supply device 1 includes a switching element 10, a power conversion transformer 11, and an overcurrent detection circuit 12.
And a control circuit 13 for the switching element 10. Similarly, the power supply device 2 includes a switching element 20
, A power conversion transformer 21, an overcurrent detection circuit 22, and a control circuit 23 for the switching element 20.

FIG. 7A is a diagram showing current-voltage output characteristics of the power supply device 1, and FIG. 7B is a diagram showing current-voltage output characteristics of the power supply device 2, and FIG. 3C is a diagram illustrating current-voltage output characteristics when the power supply devices 1 and 2 are operated in a redundant manner. As is clear from FIGS. 6 and 7, when the power supply 1 outputs the overload current I1 and the power supply 2 outputs the overload current I2, the power supply is supplied to the load line provided with the filter unit F. The maximum current is (I1 + I2). Therefore, it is necessary to design the components (the filter unit F, the connector), the pattern of the printed circuit board, and the like used in the load line with an excessive margin with respect to the steady load current.

[0006]

As described above, in the redundant operation of the power supply device, the sum of the maximum currents output from the respective power supply devices is the current flowing to the load side. Therefore, it is necessary to design the components (the filter unit F, the connector) used for the load line, the pattern of the printed circuit board, and the like so as to have an excessive margin with respect to the steady load current. However, designing to have the above-mentioned excessive margin is necessary to reduce the size and cost of the load-side device.
This is a big problem.

In recent years, what is called a local power supply system using a battery or a dry battery for supplying power to a load-side device has been increasing. In the local power supply method, when the load current increases due to a failure of the load-side device, how to limit the load current is as follows.
This is important in realizing miniaturization of the power supply device and the load device. In particular, how to reduce the discharge from a battery or a dry battery becomes a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and in a redundant operation system for a power supply device, a redundant operation system for a power supply device which contributes to downsizing and cost reduction of a load side device. The purpose is to provide.
Also, the present invention provides a redundant power supply operation system for a local power supply system using a battery or a dry battery, which prevents discharge from the battery or the dry battery at the time of overload and contributes to downsizing and cost reduction of the load side device. The purpose is to provide.

[0009]

According to a redundant operation system for a power supply device according to the present invention, a plurality of power supply devices are connected in parallel with each other to supply current to a load. Each of the plurality of power supply devices includes a power supply device overcurrent detection unit for protecting its own power supply device, and detects whether or not the total current supplied to the load from the plurality of power supply devices exceeds the load-side overcurrent. A load-side overcurrent detection unit is provided at a preceding stage on the load side, and each power supply unit outputs a power supply overcurrent detection signal output from its own power supply unit overcurrent detection unit or an output from the load-side overcurrent detection unit. And a current control means for stopping an output current from the power supply device when the load-side overcurrent detection signal is received.

According to the first aspect of the present invention, when the power supply device overcurrent detection means provided for each power supply device detects the power supply device overcurrent, the current control means of the power supply device cuts off the output current. In addition, when the load-side overcurrent detection means detects the load-side overcurrent, the current control means of each power supply unit cuts off the current output from each power supply unit. According to the redundant operation system of the power supply device according to the second aspect, in the redundant operation system of the power supply device according to the first aspect, the load-side overcurrent detection means includes a voltage generated at both ends of a resistor connected to the load line. By comparing with a predetermined reference voltage, it is detected whether or not the total current supplied to the load from the plurality of power supplies exceeds the load-side overcurrent.

According to the second aspect of the present invention, the load-side overcurrent detecting means reliably detects whether or not the total current supplied to the load from the plurality of power supplies exceeds the load-side overcurrent. be able to. According to the redundant operation system of the power supply device according to the third aspect, in the redundant operation system of the power supply device according to the first aspect, the load-side overcurrent detection means includes a voltage generated at both ends of a resistor connected to a load line. And a reference voltage determined in advance for each power supply device, thereby distinguishing a power supply device that operates and a power supply device that stops operation among a plurality of power supply devices.

According to the third aspect of the present invention, in the redundant operation system of the power supply device according to the first aspect, it is possible to reliably distinguish a power supply device that operates for each power supply device and a power supply device that stops operation. . According to the redundant operation system of the power supply device, at least one of the plurality of power supply devices is a backup power supply device driven by a battery or a dry battery, and other than the backup power supply device during normal operation. The power supply unit operates to supply power to the load side, and the backup power supply unit supplies current to the load only when the operation of the other power supply unit is interrupted. The maximum output voltage of the backup power supply is set to a value smaller than the maximum output voltage of the other power supplies, and the total current supplied to the load from multiple power supplies exceeds the load side overcurrent. Load-side overcurrent detection means for detecting whether or not the load is present is provided at a stage preceding the load, and the load-side overcurrent detection means is provided at both ends of a resistor connected to a load line. And a reference voltage predetermined for each power supply device, and outputting a load-side overcurrent detection signal only to the power supply device that exceeds the reference voltage, thereby operating the plurality of power supply devices. Distinguish between the power supply to perform and the power supply to stop operation,
In addition, the reference voltage of the backup power supply device is set to a value smaller than the reference voltage of another power supply device.

According to the present invention, the maximum value of the output voltage of the backup power supply is set to a value smaller than the maximum value of the output voltage of the other power supply, and the reference voltage of the backup power supply is Is set to a value smaller than the reference voltage of the other power supply device, so that the current is supplied from the power supply device other than the backup power supply device to the load side in both the normal operation and the load side overcurrent.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments shown in the accompanying drawings will be described below. FIG. 1 is a circuit diagram showing a first embodiment of the present invention, and shows a redundant operation system in which three power supplies 1, 2, 3 are connected. This embodiment corresponds to claim 1. In the embodiment shown in FIG. 1, the same parts as those in the prior art shown in FIG. 6 are denoted by the same reference numerals, and description thereof will be omitted. The difference between the prior art shown in FIG. 6 and the first embodiment shown in FIG. 1 is as follows.

First, in the prior art shown in FIG.
In the embodiment shown in FIG. 1, three power supplies 1, 2 and 3 are operated in parallel, and the power supplies 1, 2 and 3 are output in parallel. Current I
1 is input to the load line connected to the filter unit F. Here, the configuration of each unit of the power supply device 3 is the same as that of the power supply devices 1 and 2, and includes a switching element 30, a power conversion transformer 31, an overcurrent detection circuit 32, and a control circuit 33 of the switching element 30. I have. In addition,
In the illustrated first embodiment, the number of power supplies for performing the redundant operation is set to three, but the number may be arbitrary.

Second, an overcurrent detection circuit 4 for the load is provided on a load line connecting the three power supplies 1, 2, 3 and the filter section F. When an overcurrent flows in the load line, the overcurrent detection circuit 4 on the load side controls the control circuits 13, 23 of the switching elements 10, 20, 30 provided in the power supplies 1, 2, 3 respectively. , 33 are output with an overcurrent detection signal. As a result, each of the control circuits 13, 23, 33 is switched by the switching element 10, 2,
The operations of the power supplies 0, 30 are stopped, and the outputs of the power supplies 1, 2, 3 are stopped. Thus, the current supply from the power supply devices 1, 2, 3 to the load side is stopped.

FIG. 2 is a circuit diagram showing an example of the overcurrent detection circuit 4 shown in FIG. This corresponds to the second aspect of the present invention. As shown in the figure, a voltage generated when a load current flows across both ends of a resistor R1 provided on a load line is detected, and the detected voltage is a reference voltage V of the battery B.
Is compared to If the detected voltage is higher than the reference voltage V, each switching element 1 of each of the power supply devices 1, 2, 3
0, 20, and 30 control circuits 13, 23, and 33
The MP outputs a load-side overcurrent detection signal. Thereby, the control circuits 13, 23, 33 of the power supply units 1, 2, 3
Stops the switching operation of the switching elements 10, 20, 30 and stops the output of electric power.

Although the overcurrent detection circuit 4 shown in FIG. 2 has an example in which only one amplifier AMP and one reference voltage V (battery B) are provided, the present invention is not limited to this.
A plurality of amplifiers AMP and reference voltages (batteries) may be provided, and the overcurrent detected on the load side may be set to a different value for each power supply device. This corresponds to the third aspect of the present invention. In addition,
Needless to say, in the first embodiment described above,
The plurality of power supply devices may be driven by an AC input or may be driven by a DC input.

According to the first embodiment, the overcurrent flowing on the load side can be set to an appropriate value.
The operation of the plurality of power supply devices can be appropriately controlled.
Here, the appropriate value of the load-side overcurrent may be, for example, I <(load-side overcurrent) ≦ 3I, where I is the maximum output current of each of the power supply devices 1, 2, and 3. Therefore, unlike the related art, it is not necessary to design the load-side device to have an excessive margin with respect to the steady load current, and it is possible to reduce the size and cost of the load-side device.

FIG. 3 is a circuit diagram showing a second embodiment of the present invention, and shows a redundant operation system in which two power supplies 5 and 6 are connected. The second embodiment shown in FIG. 3 shows a local power supply AC input power supply device having a backup function using a battery or a dry cell. Needless to say, the number of power supply devices is not limited to two. Here, the second embodiment shown in FIG.
Corresponds to the invention described in (1).

In the local power supply AC input power supply shown in FIG. 3, only the power supply 5 driven by the input AC is normally operated to supply power, and the power supply 6 is connected to the battery when the power supply 5 is cut off. It is backed up by BA (or dry cell) drive. FIG. 4 is a diagram illustrating current-voltage output characteristics of the power supply devices 5 and 6. In FIG. 4, the characteristics shown by the solid line are the current-voltage output characteristics of the power supply device 5, and the characteristics shown by the dotted line are the current-voltage output characteristics of the power supply device 6.

As is apparent from FIG. 4, the output voltage V5 of the power supply 5 is higher than the output voltage V6 of the power supply 6, so that the power supply 6 operates unless the power supply 5 stops operating for some reason. Never. As shown in FIG. 3, the power supply device 5 includes an AC input AC, a switching element 50, a power conversion transformer 51, and a control circuit 53 for the switching element 50. Similarly, the power supply device 6 includes a battery BA (or a dry cell), a switching element 60, a power conversion transformer 61, and a control circuit 63 for the switching element 60.

A diode D is provided on the output line of the power supply 6 to prevent the output current of the power supply 5 from flowing back to the power supply 6. A load-side overcurrent detection circuit 4 is provided between the power supply devices 5 and 6 and the filter unit F, as in the first embodiment. FIG. 5 is a circuit diagram showing an example of the overcurrent detection circuit 4 shown in FIG.
As shown in the figure, a voltage generated when a load current flows through both ends of a resistor R1 provided on a load line is detected, and the detected voltage is a reference voltage Vac of the batteries B1 and B2.
Vdc. Here, the relationship of reference voltage Vac> reference voltage Vdc is established.

The redundant operation of the power supply device shown in FIG. 3 is performed as follows. In other words, during normal operation, a current is supplied to the load side from the power supply device 5 whose output voltage is set to a large value (V5), so that the backup power supply whose output voltage is set to a small value (V6) No power is supplied from the device 6. That is, the battery is not discharged from the backup battery BA (dry battery).

When an overcurrent flows to the load while the power supply 5 is operating (the power supply 6 is stopped), the following operation is performed. That is, when the voltage detected by the overcurrent detection circuit 4 becomes higher than the reference voltage Vdc, the control circuit 63 of the switching element 60 of the power supply 6
AMP2 outputs a load-side overcurrent detection signal. Therefore, the operation of the backup power supply device 6 is prohibited, and the power supply device 6 does not start operating.

When the voltage detected by the overcurrent detection circuit 4 becomes larger than the reference voltage Vac, the control circuit 53 of the switching element 50 of the power supply 5
AMP1 outputs a load-side overcurrent detection signal. As a result, the operation of the power supply device 5 is stopped. Further, it is assumed that the power supply device 5 is down for some reason and an overcurrent flows to the load side while the backup power supply device 6 is operating. In this case, when the voltage detected by the overcurrent detection circuit 4 becomes higher than the reference voltage Vdc, a load-side overcurrent detection signal is output from the amplifier AMP2 to the control circuit 63 of the switching element 60 of the power supply device 6. Is done. Therefore, the operation of the backup power supply device 6 is prohibited, and the power supply device 6 does not continue operating.

Therefore, power is supplied only from the power supply 5 and not from the backup power supply 6 even in the case of overload as well as in the steady state. Power is supplied from the backup power supply 6 to the load only when the output of the power supply 5 is interrupted for some reason. As is apparent from the above description, according to the second embodiment, except when the power supply device 5 is disconnected for some reason, power supply from only the power supply device 5 is possible not only in a steady state but also in an overload state. Because
The consumption of the energy stored in the battery (dry cell) BA can be prevented.

According to the second embodiment, similarly to the first embodiment, the overcurrent flowing to the load is set to an appropriate value and the operation of the plurality of power supply devices is controlled. can do. Therefore, unlike the related art, it is not necessary to design the load-side device to have an excessive margin with respect to the steady load current, and it is possible to reduce the size and cost of the load-side device.

[0029]

According to the first aspect of the present invention, when the load side overcurrent detecting means detects the load side overcurrent, the current control means of each power supply unit cuts off the current output from each power supply unit. . Therefore, by setting the load side overcurrent to an appropriate value, the components (the filter portion F, the connector) used for the load line and the pattern of the printed circuit board have an appropriate margin with respect to the steady load current. It becomes possible to design. Therefore, it is possible to reduce the size and cost of the load-side device.

According to the second aspect of the present invention, it is possible to reliably detect whether or not the total current supplied to the load from the plurality of power supplies exceeds the load-side overcurrent and notify each power supply. Therefore, it is possible to design the components (the filter unit F, the connector) used for the load line, the pattern of the printed circuit board, and the like with an appropriate margin for the steady load current. Therefore, it is possible to reduce the size and cost of the load-side device.

According to the third aspect of the present invention, the detection value of the overcurrent on the load side can be set to a different value for each power supply device, so that the current is output for each power supply device according to the value of the current flowing to the load side. It is possible to distinguish a power supply device that does not output a current from a power supply device that outputs a current. According to the invention described in claim 4, during normal operation, a current is supplied to the load side in order from a power supply device whose output voltage is set to a large value, and a backup power supply whose output voltage is set to a minimum value. Power can be prevented from being supplied from the device.

According to the present invention, the reference voltage for outputting the power supply overcurrent detection signal to the backup power supply is set to a value smaller than the reference voltage of the other power supply. Therefore, even at the time of overload, among the plurality of power supply devices, the operation of the backup power supply device first stops, and current is supplied to the load side from power supply devices other than the backup power supply device. As a result, it is possible to provide a redundant operation system of a power supply device that prevents discharge from a battery or a dry battery even during an overload and contributes to downsizing and cost reduction of a load-side device.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing an example of an overcurrent detection circuit 4 shown in FIG.

FIG. 3 is a circuit diagram showing a second embodiment of the present invention.

4 is a diagram showing current-voltage output characteristics of power supply devices 5 and 6 shown in FIG.

FIG. 5 is a circuit diagram showing an example of an overcurrent detection circuit 4 shown in FIG.

FIG. 6 is a diagram illustrating a redundant operation system of a power supply device that supplies a current to a load (not shown) connected to a filter unit using two power supply devices 1 and 2;

7A is a diagram illustrating current-voltage output characteristics of the power supply device 1, FIG. 7B is a diagram illustrating current-voltage output characteristics of the power supply device 2, and FIG. 7C is a power supply device. It is a figure which shows the current-voltage output characteristic at the time of 1 and 2 performing redundant operation.

[Explanation of symbols]

1, 2, 3, 5, 6 power supply device 4 load side overcurrent detection circuit 10, 20, 30, 50, 60 switching element 11, 21, 31, 51, 61 power conversion transformer 12, 22, 32, 52 , 62 Overcurrent detection circuit of power supply device 12, 23, 33, 53, 63 Switching element control circuit F Filter section AMP, AMP1, AMP2 Amplifier B, B1, B2 Battery D Diode R1 Resistance

Claims (4)

[Claims] 1. A plurality of power supplies are connected in parallel with each other,
In a redundant operation system of a power supply device for supplying a current to a load, the plurality of power supply devices each include a power supply overcurrent detection unit for protecting its own power supply device, and a plurality of power supply devices supplied to the load from the plurality of power supply devices. A load-side overcurrent detecting means for detecting whether or not the current exceeds a load-side overcurrent is provided at a stage preceding the load; and each power supply device has a power supply output from its own power supply device overcurrent detection means. Redundant operation of the power supply device, comprising current control means for stopping output current from the power supply device when receiving a device overcurrent detection signal or a load-side overcurrent detection signal output from the load-side overcurrent detection means. system. 2. The load-side overcurrent detecting means compares a voltage generated at both ends of a resistor connected to a load line with a predetermined reference voltage to supply the load from a plurality of power supply devices to the load. The redundant operation system for a power supply device according to claim 1, wherein whether or not the total current to be performed exceeds a load-side overcurrent is detected. 3. The load-side overcurrent detection means compares a voltage generated at both ends of a resistor connected to a load line with a reference voltage predetermined for each power supply device.
2. The redundant operation system for a power supply device according to claim 1, wherein a power supply device that operates and a power supply device that stops operation are distinguished among the plurality of power supply devices. 4. A backup power supply device driven by a battery or a dry battery, wherein at least one of the plurality of power supply devices is a backup power supply device. In the redundant operation system of the power supply device that supplies power and the backup power supply device supplies current to the load only when the operation of the other power supply device is interrupted, the maximum output voltage of the backup power supply device is: It is set to a value smaller than the maximum output voltage of the other power supplies, and the total current supplied to the load from the plurality of power supplies is
Load-side overcurrent detection means for detecting whether or not the load-side overcurrent has been exceeded is provided at a preceding stage of the load, and the load-side overcurrent detection means includes a voltage generated at both ends of a resistor connected to a load line. By comparing a reference voltage predetermined for each power supply device in advance, a power supply device that operates and a power supply device that stops operation among a plurality of power supply devices are distinguished, and the reference voltage of a backup power supply device is A redundant operation system for a power supply, wherein the value is set to a value smaller than a reference voltage of another power supply.