JP2019004560A - Redundancy power supply system - Google Patents

Abstract

To provide a redundancy power supply in which seamless power supply switching having no interruption and having less voltage reduction is performed while power consumption and the cost are suppressed, whereby the risk of concentrative occurrence of power supply failures.SOLUTION: When a power supply voltage detection circuit 31 determines that the output voltage of auxiliary power supplies 12-2 to 12-n is equal to or less than a first threshold Vth1 on the basis of voltages detected by voltage detectors 21-2 to 21-n, a gate control driving circuit 32 performs switching operation of the current power supply by controlling the on/off of gate circuits 22-1 to 22-n. Voltage for turning off is outputted to a gate (G) of a gate circuit 22-1. Next, a gate circuit 22-2 of a power supply 12-2 which is a next auxiliary power supply, among the auxiliary power supplies, in accordance with an order predetermined by a control sequence, is turned on.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a redundant power supply system for a device that is expected to be continuously operated, such as a security monitoring camera and a recording device.

  In recent years, the number of systems that cause inconveniences such as security surveillance cameras and hard disks that can be stopped for a moment, such as continuous monitoring and recording, has increased. Furthermore, the required current capacity is increasing due to the advancement and size of the system.

  In an example of a conventional monitoring / recording device, there is a case in which one power supply device is installed in one system, and when the power supply device fails, monitoring and recording stops until the power supply device is replaced.

As a redundancy technology for a conventional power supply device that is often used to eliminate the inconvenience, a method using a storage battery or a plurality of power supplies connected in parallel (this method is called “Oring connection”) is used.
Hereinafter, a conventional method using the Oring connection will be described with reference to FIGS. 13 and 14, reference numeral 100 denotes a redundant power supply block. In the configuration, the outputs of the plurality of power supplies 102 are connected to the anodes of the corresponding diodes 104, and the cathode side of all the diodes is connected to the load electronic device 120. At this time, the input of the power source 102 is supplied with power from a commercial AC power source or a CVCF (Constant Voltage Constant Frequency) 110. The outputs of the plurality of power supplies 102 supply power through a diode to the load at a rate corresponding to the output voltage. When a voltage drop failure occurs in one power supply, the diode prevents the diode from connecting to the failed power supply on the anode side of the diode and the reverse current from flowing through the diode, preventing the failure power supply. Separate. At this time, power is supplied to the load from another power source that has not failed, so that the system is not disturbed and is replaced with a new power source during this time. By supplying power to a load from a plurality of power supplies, the burden on each power supply can be reduced, thereby extending the life of each power supply, and thus the life of the system.

  FIG. 14 shows an example in which the FET 204 is used instead of the diode in order to suppress the voltage drop and power consumption in the diode 104. When using an FET, since the FET has a bidirectional conduction property, the voltage difference between both ends is detected in order to prevent a backflow to a low output voltage power supply due to a voltage difference between the plurality of power supplies 102. A voltage difference monitoring / FET control circuit 206 for controlling on / off of the gate is provided. When using an FET, a voltage difference occurs even when the power supply fails, so not only the difference in the output voltage of the power supply, but also when the power supply voltage drops, the FET is turned off by monitoring the voltage difference to prevent backflow. Disconnect the failed power supply from the system and replace it with a new one. At this time, power is supplied to the load from another power source so that the system is not hindered. The life of the power supply / system is the same as that of the diode.

JP 2010-220304 A JP2015-050814A JP 2009-55686 A

  In the above-described conventional methods using power supply redundancy shown in FIGS. 13 and 14, both of the power supply systems are connected in parallel, and the power supply burden of the power supply is made the same, thereby making the power supply system redundant and having a long service life. In order to achieve this, there is a demerit that power supplies having the same output voltage must be prepared for all the power supplies to be configured. In addition, in the case of power supplies with uniform performance, power supplies introduced at the same time are likely to fail almost at the same time, and there is a demerit that the failure of the same system may continue and the risk of simultaneous failure increases. .

  When the power supply is configured as a power supply with a difference in output voltage, a power supply with a high output voltage always bears more load power, and a power supply with a low output voltage does not contribute to supply of load power. Become. Therefore, since a power source with a high output voltage contributes to supply of a large amount of load power, the lifetime comes earlier than other power sources, while a power source with a low output voltage contributes little and has a long lifetime. Therefore, a power supply with a low output voltage has a life span due to aging without contributing to supply of load power. In addition, in this configuration, the burden of supplying power to the load is not related to the old and new power supplies, so it does not fail from the old power supply, the failure interval is random, and the possibility of simultaneous failure is increased. There is.

  In particular, in a power supply that handles a large current of 1 A or more, the diode configuration of the conventional method of FIG. 13 has a demerit that there are many voltage drops at the diode and wasteful power consumption.

  As shown in FIG. 14, in the case of a method constituted by a MOSFET (metal-oxide-semiconductor field-effect transistor) having a low Rds with a small Rds (drain-source resistance) instead of a diode, the voltage drop and the power consumption are This is a significant improvement compared to the case of using a diode, but it is necessary to set the power supply secondary side impedance so that a reverse current that can be sensed with the accuracy of voltage difference monitoring flows when an abnormality occurs in the power supply. There is a demerit that wasteful power is always consumed.

  When making power supply units redundant, it is necessary to consider the case where each power supply unit consists of multiple power supplies or supplies current with a single power supply. Therefore, there is no merit of parallel supply by the Oring connection or the like from the viewpoint of performance required for the power source to be configured.

  The present invention is intended to solve such problems of the prior art, and in the power redundancy, the power consumption is reduced, the life of the power supply system is extended by the effective use of the power supply, and The purpose is to realize stabilization of the output voltage.

  In order to achieve the above object, according to the present invention, there is provided a power supply system including at least one spare power supply and supplying power using one power supply as an active power supply in addition to the standby power supply. Voltage monitoring means for monitoring the voltage, power supply switching means for performing a power supply switching operation using the standby power supply as a new working power supply on the condition that the voltage of the working power supply has dropped below the first threshold, and output to the load A power supply system is provided that includes a compensation circuit that compensates not to fall below a second threshold.

  In one preferred aspect, the voltage monitoring unit monitors a voltage of the working power supply and the standby power supply, and provides a system for notifying an abnormality display, an alarm, etc. to the power supply that has detected that the voltage has dropped below the first threshold. It has.

In one preferred embodiment, the voltage monitoring means determines that a failure has occurred when the voltage of the working power supply has fallen below a first threshold value, and switches the power supply to a new working power supply. I do. The power switching operation is performed by a logic circuit using a semiconductor logic IC or a program using a microcontroller IC. The order of switching from a plurality of standby power supplies to a new working power supply is designated in advance by a logic circuit when a semiconductor logic IC is used, and by a program when a microcontroller IC is used. In addition, a gate circuit composed of, for example, a low on-resistance MOSFET is provided for turning off the connection to the load of the standby power supply to be a new working power supply while turning off the connection to the load of the failed working power supply.
It is sufficient that there is at least one standby power supply in relation to the risk of failure and the trouble of replacement, regardless of the number.

  In one preferred embodiment, when the power supply switching operation is performed due to the failure of the working power supply, the working power supply is turned off and the standby power supply is shifted to a new working power supply. As a first response to the voltage drop due to the load current during this deviation, a structure having a capacitor (capacitance) on the load side is adopted. Compensation with backflow prevention that guarantees the minimum required voltage on the load side as a second measure when the circuit has a load current that cannot be handled by the capacitor on the load side or when a sufficient capacitor cannot be prepared Circuit.

  In one preferred embodiment, a logic circuit using a semiconductor logic IC, a circuit using a microcontroller IC, a circuit for controlling a MOSFET, and a voltage compensation circuit that guarantees a minimum voltage each have a power supply circuit required. . For example, a low Vf Schottky barrier diode with a small voltage drop for preventing backflow is arranged at the input of the power supply circuit, and is connected to the outputs of the working power supply and a plurality of standby power supplies. Further, the power supply circuit can be used for notifying an abnormality display based on a signal from a logic circuit or a microcontroller circuit, an alarm notification system, a reset, or the like, including a standby power supply.

  A redundant power supply system according to a first aspect of the present invention is a redundant power supply system that supplies power by selecting at least one of a plurality of power supplies as a working power supply, and detects at least a voltage of the working power supply. When at least one of the plurality of power supplies is selected as a working power supply, and the voltage of the working power supply detected by the power supply voltage detecting circuit falls below a first threshold value, A power source selection circuit that switches among a plurality of power sources to select as a new working power source, and a voltage compensation circuit that compensates a voltage at a supply point for supplying the power to a second threshold value or more.

  Preferably, the voltage compensation circuit compensates the supply point voltage to be equal to or higher than the second threshold value based on the voltage from the power supply.

  Preferably, the power converter further includes a voltage conversion circuit that converts a voltage supplied from each of the plurality of power supplies via a forward diode to a predetermined DC voltage, and the voltage compensation circuit is supplied from the voltage conversion circuit. Based on the converted voltage, the voltage at the supply point is compensated to be equal to or higher than the second threshold value.

  Preferably, the voltage compensation circuit includes a gate circuit interposed between the cathode of the diode and the supply point and controlled based on the converted voltage from the voltage conversion circuit.

  Preferably, the voltage compensation circuit includes a shunt regulator that controls the gate circuit based on the converted voltage of the voltage conversion circuit by changing impedance according to the potential of the supply point.

  Preferably, the power supply voltage detection circuit detects voltages of the plurality of power supplies, and the power supply selection circuit selects a normal power supply among the plurality of power supplies based on the voltage detected by the power supply voltage detection circuit. The new working power source is selected.

  Preferably, the power supply selection circuit includes a MOSFET gate connected back-to-back with a semiconductor control circuit that operates based on a detection result of the power supply voltage detection circuit.

  Preferably, the power supply selection circuit includes a control circuit for turning on and off the MOSFET gate so that one working power supply supplies power to the supply point.

  A redundant power supply system according to a second aspect of the present invention is a redundant power supply system that supplies power by selecting at least one of a plurality of switching AC / DC power supplies as an active power supply, and at least the active power supply system. When a power supply state detection circuit for detecting an oscillation state in the power supply and at least one of the plurality of power supplies is selected as a working power supply, and the oscillation state of the working power supply detected by the power supply state detection circuit is an abnormal state A power source selection circuit that switches among the plurality of power sources to select as a new working power source, and a voltage compensation circuit that compensates a voltage at a supply point for supplying the power to a second threshold value or more. Have.

  Preferably, the power supply voltage detection circuit further detects at least the voltage of the working power supply, and the power supply selection circuit has a voltage of the working power supply detected by the power supply voltage detection circuit equal to or lower than a first threshold value. When the power supply voltage is lowered or when the oscillation state of the working power supply detected by the power supply state detection circuit is an abnormal state, the working power supply is switched from the plurality of power supplies and selected as the new working power supply.

  According to the present invention, it is possible to reduce power consumption, extend the life of a power supply system by effectively using a power supply, and stabilize the output voltage when making a power supply redundant.

FIG. 1 is an overall configuration diagram of a redundant power supply system according to a first embodiment of this invention. FIG. 2 is a diagram for explaining the normal operation of the voltage detectors 21-1 to 21-n, the power supply voltage detection circuit 31, and the gate control drive circuit 32 shown in FIG. FIG. 3 is a diagram for explaining a state after an abnormality has occurred in the working power supply. FIG. 4 is a conceptual diagram of voltage transition in the case where an abnormality occurs in the working power supply and there is no standby power supply in FIG. FIG. 5 shows a case in which when the power supply to the load electronic device is small in FIG. 3, an abnormality occurs in the working power supply, and when the switching to the standby power supply is performed when it falls below the first threshold value Vth1 with time. It is a conceptual diagram of voltage transition. FIG. 6 is a conceptual diagram of voltage transition in the case where the power supply to the load electronic device in FIG. 5 is large and is lower than the first threshold value Vth1 and the second threshold value Vth2. FIG. 7 is a conceptual diagram of a voltage compensation function in the voltage compensation circuit that outputs the second threshold value Vth2 in FIG. FIG. 8 is a diagram showing a sequence of monitoring and power supply switching by the power supply voltage detection circuit and the gate control drive circuit in FIG. FIG. 9 is a diagram showing a first form of the configuration of the voltage compensation circuit in FIG. FIG. 10 is a reference example of performance comparison between the diode and MOSFET reference element products in FIGS. 1 and 3. FIG. 11 is an overall configuration diagram of a redundant power supply system according to the second embodiment of this invention. FIG. 12 is a diagram showing a power supply switching sequence in FIG. FIG. 13 is a diagram showing a configuration of a conventional general redundant power supply system for a load electronic device. FIG. 14 is a diagram showing a conventional configuration when the FET is replaced with an FET in consideration of the power consumption of the diode used as the redundancy method in FIG.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[First Embodiment]
FIG. 1 is an overall configuration diagram of a redundant power supply system 1 according to a first embodiment of the present invention.
As shown in FIG. 1, the redundant power supply system 1 includes, for example, a power supply module 10 and a redundant circuit block 20 and supplies power to the load electronic device 30.

  The redundant power supply system 1 is configured in advance so as to back up one active power supply with a plurality of standby power supplies.

  As shown in FIG. 1, the power supply module 10 includes an AC power supply 11 that is an AC power supply or CVCF, and a plurality of power supplies 12-1 to 12-n (n is an integer of 2 or more). The power supplies 12-1 to 12-n are AC / DC power supplies.

The redundant circuit block 20 is interposed between the power supply module 10 and a supply point 29 to which the load electronic device 30 that is a power supply destination is connected.
As shown in FIG. 1, the redundant circuit block 20 includes, for example, voltage detectors 21-1 to 21-n, gate circuits 22-1 to 22-n, diodes 24-1 to 24-n, and a DC / DC converter circuit. 25, a voltage compensation circuit 26, a capacitor 28, a power supply voltage detection circuit 31, and a gate control drive circuit 32.

  The voltage detectors 21-1 to 21-n detect output voltages of the power supplies 12-1 to 12-n, respectively.

  The power supply voltage detection circuit 31 outputs the output voltage detected by the voltage detectors 21-1 to 21-n to the gate control drive circuit 32.

  The gate circuits 22-1 to 22-n are MOSFET blocks that serve as gates for conducting and blocking between the outputs of the power supplies 12-1 to 12-n and the supply points 29 (loads), respectively.

The gate control drive circuit 32 controls and drives the gate circuits 22-1 to 22-n based on the output voltage detected from the power supply voltage detection circuit 31.
The gate control drive circuit 32 selects at least one of the power supplies 12-1 to 12-n as the working power supply, and the voltage of the working power supply detected by the power supply voltage detection circuit 31 is less than or equal to the first threshold value Vth1. When the voltage drops, the power source is switched to another power source 12-1 to 12-n and a new working power source is selected.
The gate circuits 22-1 to 22-n and the gate control drive circuit 32 constitute an example of the power supply selection circuit of the present invention.

  The diodes 24-1 to 24-n are backflow prevention Schottky diodes that supply power from the power sources 12-1 to 12-n to the DC / DC converter circuit 25 and the voltage compensation circuit, respectively, and function as OR circuits.

  The DC / DC converter circuit 25 supplies power to a power source such as an IC or a microcontroller used for the voltage detectors 21-1 to 21-n and the gate control drive circuit 32.

  The voltage compensation circuit 26 sets the second threshold value Vth2 as a voltage necessary for guaranteeing the operation of the load electronic device by the load electronic device side voltage due to the difference in gate operation time during the power supply switching operation due to the failure of the working power supply. Supply power so that it does not fall below. Specifically, the voltage compensation circuit 26 supplies (compensates) power so that the voltage at the supply point 29 becomes equal to or higher than the second threshold value Vth2.

  The load electronic device 30 is connected to the supply point 29 and is a power supply destination of the redundant power supply system 1. When it is clear that the voltage does not fall below the second threshold value Vth2 when the load electronic device 30 is provided with a power supply function such as a large-capacitance capacitor and when almost no power is consumed, voltage compensation The circuit 26 may not be provided

  In FIG. 1, one of the predetermined power supplies 12-1 to 12-n is used as a working power supply, and a plurality of other power supplies 12-1 to 12-n are used as standby power supplies. The order of selection as the spare power supply is determined in advance, for example, and is incorporated in the logic of the gate control drive circuit 32 or the program software with the order of power supply switching as a sequence.

FIG. 2 is a diagram for explaining the normal operation of the voltage detectors 21-1 to 21-n, the power supply voltage detection circuit 31, and the gate control drive circuit 32 shown in FIG.
As shown in FIG. 2, each of the gate circuits 22-1 to 22-n connects two N-channel MOSFETs with low ON resistance in a back-to-back manner, and the output can hold a charge for a certain period of time. In this way, the capacitor C is arranged. A resistor R that can be ignored in terms of power consumption for voltage stabilization is disposed at a connection point between the MOSFETs.

In the example shown in FIG. 2, the power source 12-1 is selected as the working power source, and the power sources 12-2 to 12-n are standby power sources.
The voltage detectors 21-1 to 21-n and the power supply voltage detection circuit 31 detect (monitor) the voltages of the power supplies 12-1 to 12-n, and when the output voltage of the working power supply is normal, the gate control drive circuit 32 applies a voltage (indicated as “H” in FIG. 2) that can minimize the on-resistance within the rating to the gate circuit 22-1 provided between the working power supply (power supply 12-1) and the load electronic device 30. Turn on the gate. As a result, electric power is supplied from the working power source to the load electronic device 30 after being stored in the capacitor C on the load side. At this time, all the other standby power supplies are set to voltages (indicated by “L” in FIG. 2) that completely turn off the gate circuits 22-2 to 22-n according to the sequence of the gate control drive circuit 32. It is completely disconnected from the load electronic device 30, and the AC power supply is applied, but it is maintained in a no-load state.

FIG. 3 shows the redundant power supply system 1 shown in FIG. 2 in which an abnormality occurs in the working power supply and the output voltage falls below the first threshold value Vth1, and the power supply 12-2 as the standby power supply is switched and selected as the working power supply. It is a figure which shows the state at the time of performing operation.
In this case, the voltage detector 21-1 detects a voltage drop (indicated by “L” in FIG. 3) of the output voltage of the power supply 12-1 as the working power supply to the first threshold value Vth 1 or less. According to the sequence of the gate control drive circuit 32, the power supply 12-1 which is the working power supply and the load electronic device 30 are separated from each other by a voltage (indicated by “L” in FIG. 3) for turning off the gate circuit 22-1.
At the same time, the gate control drive circuit 32 is transferred to the gate of the gate circuit 22-2 that has separated the power source 12-2 as the backup power source and the load electronic device 30 based on the order incorporated in the gate control drive circuit 32 in advance. A voltage (indicated by “H” in FIG. 3) that turns on more sufficiently is applied. A voltage to be turned off (indicated by “L” in FIG. 3) is applied to the gate circuits 22-3 to 22-n connected to the power sources 12-3 to 12-n as other standby power sources, and the load electronic device 30 Will remain disconnected.

In this operation of switching the current power supply, if the output voltage of the power supply 12-2 that is a candidate for the standby power supply is equal to or lower than the first threshold value Vth1, the power supply of the next order is determined by the sequence of the gate control drive circuit 32 12-3 is raised and the power source switching operation is performed. Thereafter, the same operation is performed to switch the power supply with a normal output voltage to the working power supply.
The voltage detectors 21-1 to 21-n detect the voltages of all the power supplies 12-1 to 12-n, and only the normal power supply is selected as the working power supply by the gate control drive circuit 32.

Hereinafter, a temporal change in the DC output voltage when the above-described working power supply is abnormal and the output voltage is lowered will be described.
If the redundant circuit block 20 is not connected to a standby power supply, the capacitor C provided between the power supply 12-1 to 12-n and the load electronic device 30 as shown in FIG. The voltage is further lowered below the first threshold value Vth1 in a curve determined by the capacity and the load, and finally becomes 0V.
In this case, between the output voltage Vout1 of the power supply and the voltage VLout of the supply point 29 on the load electronic device 30 side, the voltage drop ΔV in the gate circuits 22-1 to 22-n is exactly as shown in FIG. Occurs. However, when an appropriate voltage is applied to the gate of the MOSFET, there is also a product with a maximum of 2.6 mΩ even at a current of 110 A. As shown in the product example of FIG. The drop ΔV is 52 mV, and even if two are connected back to back, the two voltage drops are about 104 mV.
In the following FIG. 5 to FIG. 7, ΔV is ignored because it is very small compared to the output voltage.

  With respect to FIG. 4 described above, a description will be given with reference to FIGS. 5 and 6 when an active power source and a standby power source are provided. There is a difference in the temporal change in the output voltage depending on the amount of current flowing through the load electronic device 30.

FIG. 5 shows that when the current flowing through the load electronic device 30 is small, the second threshold value even if the output voltage Vout1 of the working power source falls below the first threshold value Vth1 due to the influence of the charge charge of the capacitor C and the like. The case where the work for turning off the working power supply and the work for turning on the standby power supply are completed within the time not lower than Vth2 and the output voltage Vout2 of the backup power supply supplies power to the load electronic device is shown.
At this time, since the voltage drop Δ (delta) V of the gate circuits 22-1 to 22-n is very small, it can be ignored in explaining the operation. When the output voltage falls below the first threshold value Vth1, a power source switching operation is performed as shown in FIG. When the output voltage Vout1 of the working power supply falls below the first threshold value Vth1, an operation of switching the standby power supply to the working power supply is performed, and the output voltage Vout2 of the power supply 12-2 as the standby power supply is supplied to the load electronic device 30. The At this time, the time T1 required from when Vout1 falls below the first threshold value Vth1 to when switching to Vout2 is the ON / OFF switching time (timing deviation) of the gate circuits 22-1 and 22-2. .

  FIG. 6 shows a case where the current flowing through the load electronic device 30 is large and the voltage change is large in FIG. When an abnormality occurs in the power source 12-1 that is the working power source and the output voltage Vout1 falls below the first threshold value Vth1, the gate circuit 22-1 is turned off, and the power source 12-1 that is the working power source becomes the load electronic device. 30 and separated. When the working power supply is disconnected from the load electronic device 30, the voltage VLout at the supply point 29 on the load electronic device 30 side releases the charge charged in the capacitor C to the load electronic device 30, and the voltage drops. When the charged charge is smaller than the outflow current to the load electronic device 30, the voltage finally becomes 0V. When the gate on / off switching time T1 elapses, the power source 12-2, which is a standby power source, becomes a new working power source and outputs Vout2. At this time, the output voltage Vout1 of the working power supply changes toward the final voltage with the time constant of the abnormal power supply because the load becomes light.

If the voltage compensation circuit 26 shown in FIG. 1 is not provided, as shown in FIG. 6, the input voltage VLout to the load electronic device 30 is lower than the second threshold value Vth2 that must be guaranteed for the system. there is a possibility.
FIG. 7 is a diagram of the temporal change in the output voltage when the redundant circuit block 20 uses the voltage compensation circuit 26 that outputs the voltage of the second threshold value Vth2, as shown in FIG.
As shown in FIG. 7, when the voltage VLout at the supply point 29 is about to be equal to or lower than the second threshold Vth2 voltage, power is supplied from the voltage compensation circuit 26 and VLout does not fall below the second threshold Vth2 voltage. Like that.

  The voltage difference ΔVout between Vout1 and Vout2 shown in FIGS. 5, 6, and 7 is not limited as long as it satisfies the electrical requirements from the load electronic device 3. Therefore, the sign of ΔVout does not matter. As a feature of the present embodiment, the redundant circuit block 20 can be configured by using an arbitrary power source as long as the power source satisfies the load electronic device 30.

  As a countermeasure of FIG. 6, as another method, the capacity of the capacitor C is made sufficiently large to cover the current supplied to the load electronic device and the on / off switching time T1, or the switching time T1 is shortened, or both. It is also possible to change the voltage as shown in FIG. The voltage compensation circuit is not necessarily required, considering restrictions on the electronic load device 30 and the gate control drive circuit 32, the mounting area of the capacitor, the price, and the like.

FIG. 8 is a flowchart showing a first form of a control sequence by the power supply voltage detection circuit 31 and the gate control drive circuit 32 in FIG.
This configuration is based on the premise that the power supply 12-1 to 12-n has a performance sufficiently satisfied with respect to the load electronic device 30 by one unit connected to the AC power supply, and the output voltages are exactly the same. There is no need.

Step ST1:
Each power supply 12-1 to 12-n is activated.
Output voltages from the power supplies 12-1 to 12-n are supplied to the DC / DC converter circuit 25 and the voltage compensation circuit 26 via the diodes 24-1 to 24-n.
In the DC / DC converter circuit 25, the voltage is converted into a predetermined voltage and supplied to the power supply voltage detection circuit 31, the gate control drive circuit 32, and the voltage compensation circuit 26.

Step ST2:
The control sequence of the gate control drive circuit 32 is activated.
According to the activated control sequence, for example, the gate circuit 22-1 is turned on and the gate circuits 22-2 to 22-n are turned off.
As a result, the power source 12-1 is selected as the working power source, and the output voltage is supplied to the load electronic device 30 via the supply point 29. Further, the power supplies 12-2 to 12-n are backup power supplies.

Step ST3:
Based on the voltage detected by the voltage detector 21-1, the power supply voltage detection circuit 31 determines whether or not the output voltage of the power supply 12-1 as the working power supply is equal to or lower than the first threshold value Vth1.
Then, the power supply voltage detection circuit 31 proceeds to step ST6 when determining that it is equal to or lower than the first threshold value Vth1, and proceeds to step ST4 otherwise.

Step ST4:
Based on the voltage detected by the voltage detectors 21-2 to 21-n, the power supply voltage detection circuit 31 has an output voltage of the power supply 12-2 to 12-n as a standby power supply equal to or lower than the first threshold value Vth1. Judge whether there is.
Then, the power supply voltage detection circuit 31 proceeds to step ST5 when determining that it is equal to or lower than the first threshold value Vth1, and returns to step ST3 otherwise.
When the output voltages of all the standby power supplies are higher than the first threshold value Vth1, the output of the working power supply is monitored again. Repeat this.

Step ST5:
For example, the power supply voltage detection circuit 31 or the predetermined control circuit has an alarm indicating that the power supplies 12-2 to 12-n, which are backup power supplies determined to be equal to or lower than the first threshold value Vth1 in step ST4, are abnormal. Is output. The abnormality display / alarm of the output voltage can be canceled when the output voltage is restored, or can be held until it is forcibly canceled by reset or the like.

Step ST6:
For example, the power supply voltage detection circuit 31 or the predetermined control circuit outputs an alarm indicating that the power supply 12-1 that is the working power supply determined to be equal to or lower than the first threshold value Vth1 in step ST3 is abnormal.

Step ST7:
The gate control drive circuit 32 controls the on / off of the gate circuits 22-1 to 22-n to perform the switching operation of the working power source. First, the gate control drive circuit 32 outputs a voltage for turning off the gate (G) of the gate circuit 22-1 of the working power supply. Next, the gate control drive circuit 32 outputs a voltage to be turned on to the gate (G) of the gate circuit 22-2 of the power supply 12-2 that becomes the standby power supply in the next order determined in advance in the control sequence among the standby power supplies. To do. The other standby power supply gate circuits 22-3 to 22-n are kept off.

Step ST8:
The gate control drive circuit 32 sets the power supply 12-2 as a new working power supply, and at the same time, sequentially turns the power supply 12-3, which is a spare power supply, into a standby power supply to be selected next. And so on. Thereafter, the process returns to step ST1.

Hereinafter, the voltage compensation circuit 26 shown in FIG. 1 will be described in detail.
FIG. 9 is a diagram for explaining the voltage compensation circuit 26 shown in FIG.
As shown in FIG. 9, the voltage compensation circuit 26 includes, for example, gate circuits 302-1 and 302-2, resistors R1, R2, and R3, and a shunt regulator 304.

  The DC / DC converter circuit 25 is supplied with power through the outputs of all the power supplies 12-1 to 12-n and the diodes 24-1 to 24-n with a small forward voltage drop for preventing backflow.

A node 351 serving as a junction between the diodes 24-1 to 24-n and the DC / DC converter circuit 25 is connected to the drain (D) of the gate circuit 302-1.
The output of the DC / DC converter circuit 25 is connected to the MOSFET gates (G) of the gate circuits 302-1 and 302-2 via the resistor R3.
That is, the node 351 is connected to the supply point 29 (load electronic device 30) via the gate circuits 302-1 and 302-2.

The output voltage (converted voltage) of the DC / DC converter circuit 25 is a resistor R3 and a shunt regulator so that the voltage applied to the gates (G) of the MOSFETs of the gate circuits 302-1 and 302-2 is optimized. It is adjusted at 304.
The shunt regulator 304 feeds back the voltage at the supply point 29 by resistance division using the resistors R1 and R2, so that when the voltage at the supply point 29 is higher than the second threshold value Vth2, the impedance of the shunt regulator 304 is low. Thus, the voltage of the gate (G) of the MOSFETs of the gate circuits 302-1 and 302-2 is lowered to turn off the MOSFETs.

  On the other hand, when the voltage at the supply point 29 is lower than the second threshold value Vth2, the impedance of the shunt regulator 304 is increased, and the voltage to the gate of the MOSFET is increased so that the MOSFET is turned on. The power from the power sources 12-1 to 12-n is controlled and supplied to the load electronic device 30 so that the voltage at the supply point 29 is maintained at the voltage that maintains the second threshold value Vth2.

  Since the voltage compensation circuit 26 sets the supply point 29 to the voltage of the second threshold value Vth2 via the diodes 24-1 to 24-n and the gate circuits 302-1 and 302-2, the voltage drop is large. When the amount of current is large, power consumption increases. Accordingly, the supply from the voltage compensation circuit 26 is limited to a short time such as compensating for the voltage drop at the supply point 29 due to the difference in the switching timing of the gate circuits 22-1 to 22-n by the gate control drive circuit 32 described above. However, it can be used as a continuous minimum compensation circuit.

  In the gate circuits 22-1 to 22-n and the gate circuits 302-1 and 302-2 shown in FIG. 2, FIG. 3 and FIG. 9, as one embodiment, the back to two in which the source sides of two N-channel MOSFETs are connected. -Although back is shown, the drain side may be connected. As another form, the same effect can be obtained with the P-channel MOSFET by controlling the gate voltage of the P-channel MOSFET. Further, in order to divide the current and suppress the gate voltage drop, a method of connecting a plurality of gate circuits in parallel and controlling with the same gate voltage is also possible.

  FIG. 10 shows a performance comparison between the case using the N-channel MOSFET as the first form used in the gate circuits 22-1 to 22-n in FIG. 2 and the case using the conventional diode OR as a specific example. It is a table. As the MOSFET, SKI03021 manufactured by Sanken Electric Co., Ltd. was prepared as an example in which the diodes 104-1 to 104-n in FIG. It can be seen that in the range up to 40 A, both the voltage drop and the power consumption are less in the MOSFET back-to-back configuration regardless of the current passed, and the wasteful power consumption can be greatly reduced. In the catalog, S40HC1R5T manufactured by Shindengen Electric Industry Co., Ltd. has an absolute maximum rating of 40A, so comparison was made up to 40A. When selecting the actual part number, it is necessary to select the performance by considering the voltage to be used, the current to flow, etc. The above example is an example showing the effect of reducing power consumption compared to the diode OR method. .

  As described above, according to the redundant circuit block 20, the working power supply and the standby power supply are the performance required from the load electronic device 30 according to the set values of the first threshold value Vth1 and the second threshold value Vth2. Any power source having a power source can be freely selected regardless of the difference in performance.

  Further, according to the redundant circuit block 20, when the power supply 12-1 to 12-n is switched due to a failure of the working power supply, the function of the voltage compensation circuit 26 ensures the minimum voltage and enables a seamless and stable voltage supply. Thus, stable operation as a system of the load electronic device 30 becomes possible. That is, the voltage compensation circuit 26 prevents the instantaneous interruption caused by the instantaneous voltage drop caused by the timing shift at the time of the switching operation of the gate circuits 22-1 to 22-n from becoming less than the second threshold value Vth2. be able to.

  Further, according to the redundant circuit block 20, the output voltage of the standby power supply is constantly monitored together with the working power supply. Then, by notifying abnormality display, alarm, etc. based on the voltage monitoring, a standby power supply that always outputs a normal voltage after switching is selected as the working power supply. Therefore, it is possible to prevent an accident that the standby power source has failed after switching to the standby power source.

  Further, according to the redundant circuit block 20, the power sources 12-1 to 12-n determined to be abnormal are disconnected from the supply point 29 and the load electronic device 30 by the gate circuits 22-1 to 22-n. Only the failed power supply can be replaced without affecting the system of the apparatus 30.

  Further, according to the redundant circuit block 20, since the voltage compensation circuit 26 is driven based on the voltage from the power supplies 12-1 to 12-n, it is not necessary to provide a separate power supply, and the scale and cost can be reduced. Can be planned.

  Further, according to the redundant circuit block 20, the power source that is changed from the standby power source to the new working power source by switching the power source remains in a no-load state as the standby power source, so it has a long life and always replaces the failed power source with a new power source. As a result, it is possible to construct a long-term stable power supply system as a whole system.

[Second Embodiment]
FIG. 11 is a configuration diagram of a redundant power supply system according to the second embodiment of the present invention.
As shown in FIG. 11, the redundant power supply system of the second embodiment includes power supplies 12-1 to 12-n, voltage detectors 21-1 to 21-n, oscillation detectors 14-1 to 14-n, and gates. Circuits 22-1 to 22-n, an abnormality detection circuit 129, and a gate control drive circuit 132 are included.

  As shown in FIG. 11, when the power supplies 12-1 to 12-n are configured by switching AC / DC power supplies, the output voltages of the power supplies 12-1 to 12-n are converted into voltage detectors 21-1 to 21-n. And oscillation states of the output voltage are detected by the oscillation detectors 14-1 to 14-n.

  The abnormality detection circuit 129 is based on the voltage detection result by the voltage detectors 21-1 to 21-n and the detection result of the oscillation state of the output voltage by the oscillation detectors 14-1 to 14-n. Abnormality detection of the working power supply and the standby power supply is performed in .about.12-n.

  Specifically, the abnormality detection circuit 129 detects that there is an abnormality when at least one of the detected occurrence state and the detected voltage is abnormal.

  Based on the detection result of the abnormality detection circuit 129, the gate control driving circuit 132 detects the next normal standby power supply that is determined in advance when an abnormality is detected in the working power supply among the power supplies 12-1 to 12-n. Switch the working power source to.

Here, an abnormality often occurs in the oscillation state of the output voltage before an abnormality occurs in the power supplies 12-1 to 12-n and the output voltage decreases, and in this case, in the gate control drive circuit 32, Based on the detection results of the oscillation detectors 14-1 to 14-n, the abnormality of the voltage detectors 21-1 to 21-n can be detected at an early timing.
Thereby, the working power supply can be switched before the output voltage of the working power supply becomes less than the first threshold value Vth1.

FIG. 14 shows a first form of a control sequence by the oscillation detector 14, the power supply voltage detection circuit 31, the gate control drive circuit 32 and the power supply oscillation detection circuit 33 in the redundant power supply system according to the second embodiment of the present invention. It is a flowchart.
Step ST11:
Each power supply 12-1 to 12-n which is a switching AC / DC power supply is activated.

Step ST12:
The control sequence of the gate control drive circuit 32 is activated.
According to the activated control sequence, for example, the gate circuit 22-1 is turned on and the gate circuits 22-2 to 22-n are turned off.
As a result, the power source 12-1 is selected as the working power source, and the output voltage is supplied to the load electronic device 30 via the supply point 29. Further, the power supplies 12-2 to 12-n are backup power supplies.

Step ST13:
Based on the voltage detected by the voltage detector 21-1 and the oscillation state detected by the oscillation detector 14-1, the abnormality detection circuit 129 determines whether the output voltage of the power source 12-1 as the working power source is the first threshold value. It is determined whether or not Vth1 or less and whether or not the oscillation state is abnormal for the output voltage.
Then, when the abnormality detection circuit 129 determines that it is equal to or lower than the first threshold value Vth1 or the oscillation state is abnormal, the process proceeds to step ST14, otherwise proceeds to step ST15.

Step ST14:
Based on the voltage detected by the voltage detectors 21-2 to 21-n, the power supply voltage detection circuit 31 has an output voltage of the power supply 12-2 to 12-n as a standby power supply equal to or lower than the first threshold value Vth1. Judge whether there is.
The power supply oscillation detection circuit 33 determines whether or not the power supplies 12-2 to 12-n are abnormal based on the oscillation state detected by the oscillation detectors 14-2 to 14-n.
If the abnormality detection circuit 129 determines that the power supply voltage detection circuit 31 is equal to or lower than the first threshold value Vth1, or determines that the power supply oscillation detection circuit 33 is abnormal, the process proceeds to step ST15. Otherwise, the process returns to step ST13.
When the output voltages of all the standby power supplies are higher than the first threshold value Vth1 and the oscillation state is normal, the output of the working power supply is monitored again. Repeat this.

Step ST15:
For example, an alarm indicating that the power supplies 12-2 to 12-n, which are standby power supplies that are determined to be equal to or less than the first threshold value Vth1 in step ST14 or that the oscillation state is abnormal, is abnormal. Output. The abnormality display / alarm of the output voltage can be canceled when the output voltage is restored, or can be held until it is forcibly canceled by reset or the like.

Step ST16:
In step ST13, an alarm is output indicating that the power supply 12-1 that is the working power supply that is determined to be equal to or lower than the first threshold value Vth1 or that the oscillation state is abnormal is abnormal.

Step ST17:
The gate control drive circuit 32 controls the on / off of the gate circuits 22-1 to 22-n to perform the switching operation of the working power source. First, the gate control drive circuit 32 outputs a voltage for turning off to the gate circuit 22-1 of the working power supply. Next, the gate control drive circuit 32 outputs a voltage for turning on the gate circuit 22-2 of the power supply 12-2 that becomes the standby power supply in the next order determined in advance in the control sequence among the standby power supplies. The other standby power supply gate circuits 22-3 to 22-n are kept off.

Step ST18:
The gate control drive circuit 32 sets the power supply 12-2 as a new working power supply, and at the same time, sequentially turns the power supply 12-3, which is a spare power supply, into a standby power supply to be selected next. And so on. Thereafter, the process returns to step ST11.

  As described above, according to the redundant power supply system of the second embodiment, by detecting an abnormality in the switching oscillation state in the power supplies 12-1 to 12-n that occurs before the voltage of the working power supply decreases. The power supply can be switched to the standby power supply at a timing before the voltage drops to the first threshold value Vth1. Thereby, a stable voltage can be supplied to the load electronic device 30.

  In the second embodiment described above, it is determined that the power supply voltage detection circuit 31 is equal to or lower than the first threshold value Vth1, or the signals detected by the power transmission detectors 14-1 to 14-n are detected as abnormal. When the circuit 129 determines that there is an abnormality, the process proceeds to step ST15. Otherwise, the process returns to step ST13. However, the signals detected by the power transmission detectors 14-1 to 14-n are detected as abnormal. The process may proceed to step ST15 on condition that the circuit 129 is determined to be abnormal.

DESCRIPTION OF SYMBOLS 11 ... AC power supply 12-1 to 12-n ... Power supply 20 ... Redundant circuit block 21-1 to 21-n ... Voltage detector 22-1 to 22-n ... Gate circuit 24-1 to 24-n ... Diode 25 ... DC / DC converter circuit 26 ... voltage compensation circuit 28 ... capacitor 30 ... load electronic device 31 ... power supply voltage detection circuit 32 ... gate control drive circuit 33 ... power oscillation detection circuit 129 ... abnormality detection circuit 132 ... gate control drive circuit

Claims (10)

A redundant power supply system that supplies power by selecting at least one of a plurality of power supplies as a working power supply,
A power supply voltage detection circuit for detecting at least the voltage of the working power supply;
When at least one of the plurality of power supplies is selected as a working power supply and the voltage of the working power supply detected by the power supply voltage detection circuit falls below a first threshold value, the power supply is selected from the plurality of power supplies. A power supply selection circuit for switching and selecting as a new working power supply;
A redundant power supply system, comprising: a voltage compensation circuit that compensates a voltage at a supply point for supplying the power to a second threshold value or more. The redundant power supply system according to claim 1, wherein the voltage compensation circuit compensates a supply point voltage to be equal to or higher than the second threshold value based on a voltage from the power supply. A voltage conversion circuit for converting a voltage supplied from each of the plurality of power supplies via a forward diode into a predetermined DC voltage;
The redundant power supply system according to claim 2, wherein the voltage compensation circuit compensates the voltage at the supply point to be equal to or higher than the second threshold value based on the converted voltage from the voltage conversion circuit. The voltage compensation circuit is:
4. The redundant power supply system according to claim 3, further comprising: a gate circuit that is interposed between a cathode of the diode and the supply point, and that controls the voltage based on the converted voltage from the voltage conversion circuit. The voltage compensation circuit is:
The redundant power supply system according to claim 4, further comprising a shunt regulator that changes impedance according to the potential of the supply point and controls the gate circuit based on the converted voltage of the voltage conversion circuit. The power supply voltage detection circuit detects voltages of the plurality of power supplies;
The redundancy according to any one of claims 1 to 5, wherein the power supply selection circuit selects a normal power supply among the plurality of power supplies as the new working power supply based on the voltage detected by the power supply voltage detection circuit. Power system. The power supply selection circuit is configured by a MOSFET control gate connected back-to-back with a semiconductor control circuit that operates based on the detection result of the power supply voltage detection circuit.
The power supply system according to any one of claims 1 to 6. The power supply system according to claim 7, wherein the power supply selection circuit includes a control circuit that turns on and off a MOSFET gate so that one working power supply supplies power to the supply point. A redundant power supply system that supplies power by selecting at least one of a plurality of switching AC / DC power supplies as a working power supply,
A power supply state detection circuit for detecting at least an oscillation state in the working power supply;
When at least one of the plurality of power supplies is selected as a working power supply and the oscillation state of the working power supply detected by the power supply state detection circuit is abnormal, the new power supply is switched from the plurality of power supplies. A power supply selection circuit to select as a working power supply,
A redundant power supply system, comprising: a voltage compensation circuit that compensates a voltage at a supply point for supplying the power to a second threshold value or more. A power supply voltage detection circuit for detecting at least the voltage of the working power supply,
The power source selection circuit is configured such that when the voltage of the working power source detected by the power source voltage detecting circuit falls below a first threshold value, or the oscillation state of the working power source detected by the power source state detecting circuit is abnormal. 10. The redundant power supply system according to claim 9, wherein the redundant power supply system is selected from among the plurality of power supplies as a new working power supply.

Images