JP2011254660A - Electrical power system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extend an instantaneous-stop holding time without upsizing an electrical power system.SOLUTION: An electrical power system, supplying electric power to a system unit, includes: a voltage monitoring part that monitors an AC voltage; a power failure detection part that detects a power failure; and a power failure notification part that notifies the system unit of information indicating a power failure state, and transmits a power failure signal from the power failure notification part to the system unit upon the power failure. The system unit, upon reception of the power failure signal, lowers processing capacity according to a power failure time, thus reducing load power and to extend an instantaneous-stop holding time.

Description

  The present invention relates to a power supply system, and more particularly to extension of the holding time of instantaneous power interruption provided from a switching power supply device to a load.

  A switching power supply generally includes a rectifier diode that rectifies an AC voltage input from an AC power supply, a capacitor for holding an instantaneous power failure (instantaneous power failure), and a DC / DC converter, and the output of the DC / DC converter is a computer or the like. To the system unit.

  It is known that the voltage supplied to ordinary households and business establishments may cause a short voltage drop or a momentary power failure due to a lightning strike to the power transmission system. In this case, the instantaneous power interruption holding time for which the function of the power supply device is continued for a certain time when the input voltage instantaneous power interruption occurs is obtained. When the instantaneous power failure holding time is shortened, the power supply device cannot be continuously operated, and the problem becomes serious in a computer or the like that requires high reliability.

  By the way, in recent years, system devices such as computers have been further miniaturized, and switching power supply devices mounted thereon have also been required to be miniaturized. The switching power supply device can be miniaturized by high-density mounting using small components. However, when a small capacitor is used for the switching power supply device, the capacitance of the capacitor is reduced, and the instantaneous power failure holding time is shortened.

Consider the relationship between the capacitance of the capacitor and the momentary power retention time. For example, it is assumed that the input voltage AC of the switching power supply device is 200V, the load power P is 1200 W, the operation lower limit voltage VC2 of the DC / DC converter is VC2 = 141 V, and the necessary instantaneous power failure holding time Th is 20 ms.
When no AC power failure occurs, the voltage VC1 across the capacitor is expressed by equation (1) and is DC 282V.
VC1 = AC200V × √2 (1)
When a power failure occurs in the AC power supply, the capacitor is discharged, the voltage at both ends is lowered, and the output voltage is lowered when the voltage falls below the lower limit voltage of the DC / DC converter.
The capacitor capacity C necessary for securing the instantaneous power failure holding time is the voltage VC1 across the capacitor when no power failure occurs, the operation lower limit voltage VC2 of the DC / DC converter, the load power P of the switching power supply, It is calculated by the formula (2) from the instantaneous power failure holding time Th, and a specific value is 805 μF from the formula (3).
C = (2 * P * Th) / (VC1 ^ 2-VC2 ^ 2) (2)
C = (2 × 1200 W × 20 ms) / (282V ^ 2-141V ^ 2) (3)
When the switching power supply device is required to be downsized and 805 μF cannot be mounted on the capacitor, and the limit that 470 μF can be mounted, the instantaneous power failure holding time Th is calculated by Equation (4), and the specific value is expressed by Equation (5). 11 ms.
Th = (C × (VC1 ^ 2−VC2 ^ 2)) / (2 × P) (4)
Th = (470 μF × (282V ^ 2-141V ^ 2)) / (2 × 1200 W) (5)
Thus, it can be seen that the instantaneous power failure holding time is shortened when the capacitance of the capacitor is reduced by downsizing the switching power supply device.

  Therefore, it is important to reduce the size of the switching power supply device while ensuring a sufficient momentary power retention time in the power supply system, and it is possible to ensure a constant momentary power retention time even if the capacitor capacity is reduced. Is required. Regarding securing of the instantaneous power failure holding time, for example, in Patent Document 1, an output holding time extension unit equipped with a capacitor is connected to the external connection terminal of the power supply device, and the capacitance of the capacitor is substantially increased to increase the instantaneous power failure holding time. A technique for ensuring the above is disclosed. However, since this technology connects a special unit to the outside of the power supply device, it is difficult to reduce the size of the entire device. Further, since a unit different from the power supply device is required, the cost increases.

JP 2006-353015 A

  An object of the present invention is to provide a power supply system capable of extending the instantaneous power failure retention time without increasing the capacitor capacity of the power supply system.

  In order to solve the above-described problems, a power supply system according to the present invention is preferably a power supply system that supplies power to a system device, wherein a power failure detection unit that monitors an AC voltage from an AC power source and detects a power failure, The power supply system includes a power failure notification unit that transmits a signal indicating a power failure state detected by the power failure detection unit to the system device.

  According to a preferred example, the power system converts a DC voltage rectified by the rectifier diode, a rectifier diode that rectifies an AC voltage input from the AC power source into a DC voltage, a capacitor for maintaining an instantaneous power failure, and the rectifier diode. The switching power supply device includes a DC / DC converter and supplies the output of the DC / DC converter to the system device.

Preferably, the power supply system is arranged in a PDU having a circuit breaker that supplies an AC voltage to a switching power supply device corresponding to the system device.
Preferably, the power supply system is disposed in an outlet box that supplies an AC voltage to a switching power supply device corresponding to the system device.
Preferably, the power supply system is arranged in a UPS that supplies an AC voltage to a switching power supply device corresponding to the system device.

The power supply system according to the present invention is preferably a power supply system that supplies power to a system device from a switching power supply device.
The switching power supply device converts a DC voltage rectified by the rectifier diode that rectifies an AC voltage input from the AC power source into a DC voltage, a capacitor for maintaining a momentary power failure, and the rectifier diode, and outputs the output to the system. A DC / DC converter to be supplied to the apparatus, an AC voltage from an AC power supply, a power failure detection unit for detecting a power failure, and a signal (power failure signal) indicating a power failure state detected by the power failure detection unit It has a power failure notification part to send to the device,
The system apparatus includes: a receiving unit that receives the power failure signal from the power failure notification unit; a timer that measures a power failure time after receiving the power failure signal by the receiving unit; and a power failure time measured by the timer. Thus, the power supply system is characterized by having control means for controlling the operation of the constituent elements constituting the system apparatus in a power saving state.

Preferably, the system apparatus includes, as the components, a processor that executes a program, a memory that stores information, a hard disk, and a cooling fan, and the control unit includes the processor according to a power failure time, Alternatively, the memory, the hard disk, or the cooling fan is driven to save power.
Preferably, the control means of the system device is realized by executing a program by the processor.

  According to the present invention, when a momentary power failure of the AC power supply is detected, the instantaneous power retention time is extended without increasing the capacitor capacity of the power supply system by reducing the load power by reducing the processing capacity of the system device. Is possible.

The figure which shows the structure of the power supply system by one Example of this invention. The figure which shows the operation | movement flowchart of the switching power supply by one Example. The figure which shows the operation | movement flowchart of the system apparatus by one Example. The figure which shows the structure arrange | positioned in the power supply system PDU by one Example. The figure which shows the structure arrange | positioned in the power supply system outlet box by one Example. The figure which shows the structure arrange | positioned in the power supply system UPS by one Example.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows the configuration of the power supply system.
The switching power supply device 10 is connected to a system device 14 that is a load, and performs voltage conversion on an AC input voltage from the AC power supply 12. The switching power supply device 10 includes a rectifier diode 107 that rectifies an AC input voltage into DC, a capacitor 108 for maintaining an instantaneous power failure, and a DC / DC converter 109 that converts DC voltage. Further, a voltage monitoring unit 102 that monitors the voltage of the AC power source, a power failure detection unit 103 that detects a power failure of the AC power source by monitoring the voltage in the voltage monitoring unit 102, and a system device that detects when a power failure is detected by the power failure detection unit 103 14 is provided.
As a signal transmission means from the power failure notification unit 104 to the system device 14, for example, a wired or wireless LAN (Local Area Network), USB (Universal Serial Bus), RS-232C, or the like is used. The power failure notification unit 104 transmits a power failure signal “1” when the power failure detection unit 103 detects a power failure, and transmits a power failure signal “0” when no power failure is detected.

  The system device 14 such as a computer includes a processor (CPU), a memory for storing information, an external storage device such as a hard disk (HD), and a fan for cooling these components. Various programs are executed by the processor to realize data processing, various functions, and control. Further, the system device 14 has a timer formed as hardware or software, and measures the time during which the state of the received power failure signal, that is, the state of the power failure signal “1” continues, as will be described later.

Next, the operation of the switching power supply device will be described with reference to the flowchart of FIG.
AC power is input from the AC power supply 12 to the power inputs 106a and 106b of the switching power supply 10 (S201). The voltage monitoring unit 102 monitors the input AC voltage (S202), and constantly sends an AC voltage waveform to the power failure detection unit 103 (S203). The power failure detection unit 103 determines whether the AC voltage waveform satisfies a predetermined voltage threshold (S204). In other words, since the AC voltage decreases at the time of a power failure, it is determined that a power failure occurs when the AC voltage becomes a certain AC voltage threshold value or less. The power failure detection unit 103 transmits a signal indicating whether or not a power failure is determined, that is, whether a power failure has been detected, to the power failure notification unit 104 (S205).
The power failure notification unit 104 transmits a power failure signal indicating a power failure state to the system device 14 (S206). That is, the power failure notification unit 104 transmits a power failure signal “1” when a power failure occurs, and transmits a power failure signal “0” when it is not a power failure.

Next, with reference to FIG. 3, the control operation at the time of a power failure in the system apparatus will be described.
The system device 14 such as a computer performs the following control operation by executing a power failure response program by a processor.
When receiving the power failure signal transmitted from the switching power supply device 10 (S301), the system device 14 determines the power failure signal (S302). As a result of the determination, when the power failure signal “1” is detected, the timer is turned on and measurement of the time during which the power failure state continues is started.

In this example, according to the power failure time measured by the timer, the power saving target is changed and controlled as follows.
That is, if a power failure signal “1” is detected as a result of the determination, control in power saving mode 1 (reducing the CPU clock frequency in the system device) is performed (S303). When the frequency of the CPU clock is lowered, the number of instructions processed per unit time is reduced, but power saving operation is performed.
When the power failure time measured by the timer is 5 milliseconds (msec) or more (S304), the number of operating cooling fans in the system apparatus is reduced in addition to the power saving mode 2 (power saving mode 1 or Control by lowering the rotation speed is performed (S305). Reducing the number of operating fans reduces the cooling effect but reduces power consumption. When the power failure time measured by the timer is 5 milliseconds (msec) or less (S304), the power failure signal is determined (S306). If the power failure signal “1” is detected, the control in the power saving mode 1 (lowering the frequency of the CPU clock in the system apparatus) is continued. When the power failure signal “0” is detected, the power saving mode 1 is canceled (S316).

  When the power failure time measured by the timer is 10 milliseconds or more (S307), control is performed by the power saving mode 3 (in addition to the power saving mode 2, the frequency of the memory clock in the system device is lowered) (S308). When the memory clock frequency is lowered, the memory access speed is lowered, but power saving operation is performed. When the power failure time measured by the timer is 10 milliseconds or less (S307), the power failure signal is determined (S309). If the power failure signal “1” is detected, control by the power saving mode 2 (in addition to the power saving mode 1, the number of operating cooling fans in the system apparatus is reduced or the number of rotations of the fan is reduced) is continued. When the power failure signal “0” is detected, the power saving mode 2 is canceled (S316).

  When the power failure time measured by the timer is 15 ms or longer (S310), control is performed by the power saving mode 4 (in addition to the power saving mode 3, the rotational speed of the hard disk in the system apparatus is reduced) (S311). When the power failure time measured by the timer is 15 milliseconds or less (S310), the power failure signal is determined (S312). If the power failure signal “1” is detected, the control in the power saving mode 3 (in addition to the power saving mode 2 is performed, the frequency of the memory clock in the system apparatus is lowered) is continued. When the power failure signal “0” is detected, the power saving mode 3 is canceled (S316).

  When the power failure time measured by the timer is 20 milliseconds or more (S313), control to turn off the system device is performed (S314). For example, as an off control at the time of a power failure, an auxiliary power supply is operated to perform backup processing and degeneration control by a program. When the power failure time measured by the timer is 20 milliseconds or less (S313), the power failure signal is determined (S315). If the power failure signal “1” is detected, the control by the power saving mode 4 (in addition to the power saving mode 3, the rotational speed of the hard disk in the system apparatus is lowered) is continued. When the power failure signal “0” is detected, the power saving mode 4 is canceled (S316).

Next, as an example, the input voltage AC200V of the switching power supply device, the load power P = 1200 W, the operation lower limit voltage VC2 = 141V of the DC / DC converter, the voltage VC1 = DC282V across the capacitor 108, and the necessary instantaneous power failure holding time Th = 20 ms Assume that the capacitance C of the capacitor 108 is 470 μF. This assumption is the same condition as the example described in the background art column, and indicates the instantaneous power failure holding time when the load power is reduced from 1200 W to 600 W.
The instantaneous power failure holding time Th when the load power P = 1200 W is calculated by the equation (6), and a specific value is 11 ms from the equation (7).

Th = (C × (VC1 ^ 2−VC2 ^ 2)) / (2 × P) (6)
Th = (470 μF × (282V ^ 2-141V ^ 2)) / (2 × 1200 W) (7)
The instantaneous power interruption holding time Th when the load power P = 600 W is 23 ms from the equation (8).

Th = (470 μF × (282V ^ 2-141V ^ 2)) / (2 × 600 W) (8)
Thus, by reducing the load power of the system device, it is possible to extend the instantaneous power failure holding time without increasing the capacity of the capacitor.

FIG. 4 shows a configuration in which the power supply system is arranged in a PDU (Power Distribution Unit (power tap)).
In the PDU 40, an AC power input unit 402, a voltage monitoring unit 403, a power failure detection unit 404, a power failure notification unit 405, circuit breakers 406a, 406b, 406c, and output units 407a, 407b, 407c are mounted. Arranged.
The PDU 40 is connected to three system devices 14a to 14c via switching power supplies 10a to 10c. The output unit and the switching power supply 10 can be installed according to the number of system devices 14.
Thus, by disposing the power supply system in the PDU 40, it is possible to extend the instantaneous power failure holding time even in a switching power supply device without a power failure detection function.

FIG. 5 shows a configuration in which the power supply system is arranged in the outlet box.
In the outlet box 50, an input unit 502, a voltage monitoring unit 503, a power failure detection unit 504, a power failure notification unit 505, and output units 506a, 506b, and 506c are mounted and arranged.
Thus, by disposing the power supply system in the outlet box, the instantaneous power failure holding time can be extended even for a switching power supply or PDU having no power failure detection function. The three output units 506a to 506c are connected to the three system devices 14a to 14c via the switching power supplies 10a to 10c.

FIG. 6 shows a configuration in which the power supply system is arranged in a UPS (Uninterruptible Power Supply).
In the UPS 60, a UPS input unit 602, a voltage monitoring unit 603, a power failure detection unit 604, a power failure notification unit 605, a DC / AC conversion unit 606, a battery 607, and output units 608a to 608c are mounted and arranged. The three output units 608a to 608c are connected to the three system devices 14a to 14c via the switching power supplies 10a to 10c.
As described above, by disposing the power supply system in the UPS, it is possible to extend the instantaneous power failure holding time even in a switching power supply device, a PDU, or an outlet box without a power failure detection function. Also, it is possible to extend the battery driving time of the UPS.

As an example, it is assumed that the battery capacity B = 300 VAh, the apparent power S = 1000 VA of the switching power supply, and the UPS power conversion efficiency is 0.85.
The battery driving time Tb is calculated by the equation (9), and a specific value is 15 minutes from the equation (10).
Tb = (B / S × 0.85) × 60 (9)
Tb = (300 VAh / 1000 VA × 0.85) × 60 (10)
When the load power of the system load device decreases and the apparent power S = 500 VA of the switching power supply device, the battery driving time Tb is 30 minutes from the equation (11).
Tb = (300 VAh / 500 VA × 0.85) × 60 (11)
Thus, by reducing the load power of the system device, it is possible to extend the battery driving time without increasing the battery capacity. Further, if it is not necessary to extend the battery driving time, the battery capacity can be reduced.

DESCRIPTION OF SYMBOLS 10: Switching power supply device 102: Voltage monitoring part 103: Power failure detection part 104: Power failure notification part 106a, 106b: Power supply input 107: Rectifier diode 108: Capacitor
109: DC / DC converter 110a, 110b: Power supply output 12: AC power supply 14: System device
40: PDU 402: input unit 403: voltage monitoring unit 404: power failure detection unit 405: power failure notification unit 406a, 406b, 406c: circuit breaker 407a, 407b, 407c: output unit 10a-10c: switching power supply device 14a-14c: system Device 50: Outlet box 60: UPS.

Claims (8)

In a power supply system that supplies power to a system device, the AC voltage from the AC power supply is monitored, a power failure detection unit that detects a power failure, and a signal indicating a power failure state detected by the power failure detection unit is transmitted to the system device A power supply system with a power failure notification unit. The power supply system according to claim 1, wherein a rectifier diode that rectifies an AC voltage input from the AC power source into a DC voltage, a capacitor for maintaining an instantaneous power failure, and a DC that converts the DC voltage rectified by the rectifier diode. A power supply system comprising: a DC / DC converter and configured to supply an output of the DC / DC converter to the system device. The power supply system according to claim 1, wherein the power supply system is arranged in a PDU having a circuit breaker for supplying an AC voltage to a switching power supply device corresponding to the system device. The power supply system according to claim 1, wherein the power supply system is disposed in an outlet box that supplies an AC voltage to a switching power supply device corresponding to the system device. The power supply system according to claim 1, wherein the power supply system is arranged in a UPS that supplies an AC voltage to a switching power supply device corresponding to the system device. In a power supply system that supplies power to a system device from a switching power supply device,
The switching power supply device converts a DC voltage rectified by the rectifier diode that rectifies an AC voltage input from the AC power source into a DC voltage, a capacitor for maintaining a momentary power failure, and the rectifier diode, and outputs the output to the system. A DC / DC converter to be supplied to the apparatus, an AC voltage from an AC power supply, a power failure detection unit for detecting a power failure, and a signal (power failure signal) indicating a power failure state detected by the power failure detection unit It has a power failure notification part to send to the device,
The system apparatus includes: a receiving unit that receives the power failure signal from the power failure notification unit; a timer that measures a power failure time after receiving the power failure signal by the receiving unit; and a power failure time measured by the timer. And control means for controlling the operation of the constituent elements constituting the system apparatus in a power saving state.
A power supply system characterized by that. The system apparatus includes, as the constituent elements, a processor that executes a program, a memory that stores information, a hard disk, and a cooling fan, and the control unit includes the processor or the memory according to a power failure time. The power supply system according to claim 6, wherein the hard disk or the cooling fan is driven to save power. The power supply system according to claim 6 or 7, wherein the control means of the system device is realized by executing a program by the processor.

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