JP2008022641A - Backup power-supply apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain a comparatively inexpensive structure and reliability in a backup power supply apparatus which can continuously supply DC voltage to a load at the time of a power failure of an AC power supply. <P>SOLUTION: In the backup power supply apparatus, AC voltage AC from the AC power supply 10 is converted into DC voltage and is supplied to the load 7. A charging part 2 charges a battery 3. At the time of the power failure of the AC power supply 10, DC voltage is supplied to the load 7 from the battery 3 through a diode 6 for adverse current prevention while AC voltage from an AC generator 20 driven by an engine starts. The apparatus includes a backup operation detecting means for detecting whether DC current is in a state where it is supplied to the load 7 from the battery 3 through the diode 6 or not, a charging stop means for holding a detection signal by the backup operation detecting means in a holding part 12 and stopping a charging operation of the battery 3 and a power failure detecting means 8 for resetting the holding part 12 by power restoration detection after detection of the power failure of the AC power supply 10 and resuming the charging operation of the battery 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a backup power supply apparatus that converts an AC voltage from an AC power source into a DC voltage and supplies the DC voltage to a load, charges the battery with a charger, and supplies the DC voltage from the battery to the load when the AC power supply fails. .

  The AC voltage from the AC power supply or the AC voltage from the engine-driven AC generator that starts operation when the AC power supply fails is converted to a DC constant voltage by the main power supply unit such as a switching power supply and supplied to the load. There is known a backup power supply device that converts an AC voltage from a power source into a DC voltage by a switching power supply device or the like, constantly charges the battery from a battery charging unit, and supplies a DC voltage from the battery to a load at the time of AC power failure Yes. Also, when an AC power failure occurs, the engine is started to drive the AC generator, the AC voltage from this AC generator is supplied to the main power supply unit, and the DC voltage from the main power supply unit is supplied to the load. UPS (Uninterruptable Power Supply) is also known.

  For example, as shown in FIG. 6, the main part of a conventional backup power supply apparatus receives a main power supply unit 51 having a configuration such as a switch power supply that inputs an AC voltage AC and outputs a DC constant voltage, and an AC voltage AC. When the AC power supply is normal, the output voltage Vout of the main power supply unit 51 is supplied to the load 55. The charging unit 52 has a configuration such as a switching power supply for charging the battery 53 and the backflow prevention diode 54. Then, the battery 53 is charged by the output voltage of the charging unit 52, and the charge voltage VBout has a relationship of Vout> VBout. Therefore, the reverse voltage is applied to the diode 54, and the load from the battery 53 to the load 55 is reached. No direct current is supplied. When the AC power supply is interrupted, the voltage VBout of the battery 53 is supplied to the load 55 via the diode 54 to perform backup when the AC power supply is interrupted. Also, if an AC drive driven by an engine is provided, the engine is started at the time of AC power failure and the AC generator is rotated to generate an AC voltage. Instead of the AC voltage from the AC power supply, the AC generator As described above, a configuration in which an AC voltage from the AC power supply is supplied to the main power supply unit 51 to perform backup in the event of an AC power failure is also known.

In addition, a plurality of batteries are charged in parallel by an AC / DC converter, and the battery terminal voltage, charging current, and discharging current are detected, and the AC / DC converter is controlled to control overcharging and overdischarging of the battery. Provide a function as a backup power supply that provides a controller and supplies the output voltage of the AC / DC converter or the charging voltage of the battery to a plurality of DC / DC converters in the event of a power failure, converts it to a predetermined DC voltage, and supplies it to the load The structure provided is proposed (for example, refer patent document 1).
JP 2002-18764 A

  When the AC power supply is interrupted, the output voltage of the main power supply unit 51 shown in FIG. 6 becomes zero. Therefore, as described above, the DC power is supplied from the battery 53 to the load 55 via the diode 54. Even in this case, the load 55 can be brought into an operating state. If the capacity of the battery 53 in this case is increased, the load 55 can be kept in an operating state even if the power failure time becomes longer, but there is a problem of an increase in cost due to the provision of a large capacity battery. As described above, when the AC power supply is interrupted, the engine is started and the AC generator is driven. As a result, the capacity of the battery 55 increases to the predetermined AC voltage due to the engine starting after the power failure occurs. Thus, a capacity for supplying operating power to the load 55 is sufficient until the power is supplied to the main power supply unit 51. In addition, the engine-driven AC generator is required in terms of cost to reduce its power generation capacity to the minimum necessary amount corresponding to the amount of power supplied to the load 55.

  For example, as shown in FIG. 7A, when the AC voltage input to the main power supply unit 51 becomes zero due to a power failure at time t1, the current supplied from the battery 53 to the load 55 via the diode 54 is This is as shown in FIG. Then, when an AC voltage is input to the main power source 51 by AC power recovery at time t2, the current supplied from the battery 53 to the load 55 becomes zero as shown in FIG. 7B. Further, as shown in FIG. 7C, the charging current supplied from the charging unit 52 to the battery 53 becomes zero from the time t1 of the power failure, and at the time t2, the charging unit 52 together with the main power source unit 51 is AC. Since the voltage is input, the charging current from the charging unit 52 is temporary, but a charging current according to the discharge amount corresponding to the backup power from the battery 53 to the load 55 flows. That is, before the time t1, the charging current in the flow charge state for the battery 53, but when the AC voltage is applied at the time t2, the charging current from the charging unit 52 to the battery 53 increases and gradually decreases as the charging time elapses. The charging current in the flow charge state is the same as before the power failure.

  When the AC power supply is restored at time t2, the current capacity of the AC power supply is sufficiently large, so there is no problem even if the charging current from the charging unit 52 to the battery 53 increases slightly. Is applied to the main power supply unit 51 and the charging unit 52, and the charging current of the battery 53 is supplied from the charging unit 52 as shown after time t2 in FIG. The machine needs to have an output capacity corresponding to this charging current. That is, it is necessary to increase the power capacity of the backup alternator as much as possible to supply an increasing charging current, compared to the power capacity for driving the load 55. Therefore, there has been a problem that the cost of the backup power supply device increases. Further, the battery 53 is required to maintain reliability for a long period of time. However, when an overdischarge state occurs, there is a problem that its useful life is shortened. In this way, in order to maintain the reliability of the battery 53, the battery 53 may be replaced at a predetermined period or at a backup frequency. In this case, the battery 53 may be changed according to the date of manufacture. Therefore, there is a problem that the initial charging / discharging characteristics are not always obtained. Therefore, when the battery is replaced, the charging condition of the charging unit 52 must be changed. There is a problem including a possibility of erroneous setting at the time of resetting.

  The present invention is intended to solve the above-described conventional problems, and has an inexpensive and reliable configuration without increasing the capacity of an AC generator that generates an AC voltage during a power failure of an AC power supply. A backup power supply device is provided.

  The backup power supply device of the present invention converts an AC voltage from an AC power source into a DC voltage and supplies it to a load, and converts the DC voltage into a DC voltage by a charging unit to charge a battery. In the backup power supply apparatus for supplying a DC voltage from the battery to the load through a backflow prevention diode until the AC voltage from the AC generator driven by the engine starts up and rises, the battery Backup operation detecting means for detecting whether or not a direct current is supplied to the load via the diode, and a detection signal from the backup operation detecting means is held in the holding unit to stop the charging operation of the battery The battery is reset by charging stop means and resetting the holding unit upon detection of power recovery of the AC power source after detecting a power failure of the AC power source. And a power failure detection unit to restart the charging action.

  The backup operation detection means compares the output voltage of the main power supply unit that converts the AC voltage into a DC voltage and supplies the load to the battery voltage, and starts the backup operation when the battery voltage is high. The detection signal detected as is input to the holding unit.

  The backup operation detecting means inputs a detection signal for starting a backup operation by detecting a forward voltage drop of the diode when a current is supplied from the battery to the load via the diode. It has a configuration.

  The backup operation detecting means is configured to input a detection signal to the holding unit for detecting that the current supplied to the load becomes zero by converting the AC voltage to a DC voltage and starting the backup operation. It is what you have.

  The charging unit includes a charge control unit that performs charge control with a charge characteristic corresponding to the characteristic of the battery, a conversion output unit that is controlled by the charge control unit and charges the battery, and a characteristic setting unit provided in the battery. And a characteristic setting input unit that reads the setting information when the battery is mounted and inputs the setting information to the charging control unit.

  In the event of a power failure of the AC power supply, a DC voltage is supplied from the battery to the load to perform backup. The start of the backup operation is detected, the charging operation to the battery by the charging unit is stopped, and charging is performed from the engine-driven AC generator By eliminating the need to supply power for charging the battery via the unit, the AC generator can be used as a backup power capacity for the load, and an economical backup power supply can be constructed. There is.

  Referring to FIG. 1, the backup power supply device of the present invention converts the AC voltage AC from the AC power supply 10 into a DC voltage and supplies it to the load 7, and converts it into a DC voltage by the charging unit 2 to charge the battery 3. In the event of a power failure of the AC power supply 10, the DC power is supplied from the battery 3 to the load 7 via the backflow preventing diode 6 until the AC voltage from the AC generator 20 driven by the engine starts up. A backup power supply device for supplying a voltage, and a backup operation detecting means for detecting whether or not a direct current is supplied from the battery 3 to the load 7 via the diode 6, and a detection signal by the backup operation detecting means is held. The charging stop means for holding the charging action of the battery 3 and the return detection of the AC power supply 10 after detecting the power failure of the AC power supply 10. Reset the holding portion 12, and a power failure detecting section 8 to restart the charging operation of the battery 3.

  FIG. 1 is an explanatory diagram of Embodiment 1 of the present invention, in which 1 is a main power supply unit such as a switching power supply that converts an AC voltage AC into a stabilized DC voltage and outputs it, 2 is a charging unit for battery charging, 3 is a battery, 4 is a current detection unit such as a resistor as current detection means, 5 is a switch circuit such as an electromagnetic switch, 6 is a diode for preventing backflow, 7 is a load such as various electronic circuits, and 8 is a power failure detection unit , 9 is a changeover switch circuit, 10 is a commercial AC power supply, AC power supply such as private power generation equipment in a large factory, 11 is a conversion output unit for charging a battery, 12 is a holding unit, and 13 is a voltage of the battery 3 Then, a control unit that controls the conversion output unit 11 and the switch circuit 5, 20 is an engine-driven AC generator (G), and 21 is a comparator. Va is a voltage divided by the output voltage or resistance of the main power supply unit 1, Vb is a voltage divided by the voltage or resistance of the battery 3, and Vf is a forward voltage of the diode 6. The main power supply unit 1 can employ various configurations such as a known switching power supply that applies a stabilized DC voltage to the load 7. Moreover, the battery output means already known can also be applied to the conversion output unit 11.

  When the AC power supply 10 is normal, the AC voltage AC is applied to the main power supply unit 1 and the charging unit 2 to supply a stabilized DC voltage from the main power supply unit 1 to the load 7, and the charging unit 2 To charge the battery 3. Although this charging current varies depending on the structure and characteristics of the battery 3, it is recommended that the charging current be 0.1 C to 0.3 C when the capacity of the battery 3 is C (AH). Further, since the voltage of the battery 3 is set to be lower than the output DC voltage of the main power supply unit 1 at the normal time, a reverse voltage is applied to the diode 6, and the battery 3 to the load 7. Current does not flow. The control unit 13 detects the terminal voltage of the battery 3 to control the conversion output unit 11, controls the charging current from the conversion output unit 11 to the battery 3 to avoid overcharging, Sometimes, when a direct current is supplied from the battery 3 to the load 7 via the diode 6 to indicate the overdischarge state of the battery 3 when the battery 3 is relatively long, the switch circuit 5 is turned off by the control from the control unit 13. It is possible to avoid a reduction in the usable time of the battery 3 due to overdischarge.

  The comparator 21 constitutes a backup operation detection unit, and compares the output voltage of the main power supply unit 1 with the voltage of the battery 3. When detecting that the relationship of Vb−Vf> Va is established, the comparison detection signal is held as a backup operation start detection signal by the holding unit 12 of the charging unit 2, and the held signal is converted into a conversion output unit. 11 is input as an operation stop signal to 11 and constitutes a charge stop means for stopping the charging of the battery 3. Therefore, when the AC power supply 10 is normal, the supply current from the battery 3 to the load 7 is zero as described above, and therefore the forward voltage Vf of the diode 6 is zero. In this case, the relationship Vb <Va is established, and the output of the comparator 21 indicates zero.

  Further, when the output voltage of the main power source 1 drops or becomes zero at the time of a power failure of the AC power source 10, current is supplied from the battery 3 to the load 7 via the diode 6, so that the forward voltage Vf of the diode 6 A voltage drop occurs, and the comparator 21 holds the comparison detection signal in the relationship of Vb−Vf> Va as the detection signal for starting the backup operation, as described above, in the holding unit 12 constituting the charging stop unit, The charging operation of the battery 3 is stopped. The current detection unit 4 detects a current supplied from the battery 3 to the load 7 and inputs a detection signal to the charging unit 2 so that the supplied current indicates an overcurrent state. In the same manner as described above, the current supplied to the load 7 can be cut off by controlling the switch circuit 5 from the charging unit 2. Further, the current detection signal supplied from the battery 3 to the load 7 by the current detection unit 4 is held in the holding unit 12 of the charging unit 2 in the same manner as the comparison detection signal of the comparator 21 described above, It can also be set as the structure which inputs as an operation stop signal and stops charge of the battery 3. FIG.

  In this way, when the AC power supply 10 is stopped, the charging of the battery 3 is stopped, whereby the AC generator 20 is started and the generated AC voltage is input to the main power supply unit 1 and the charging unit 2. Since the unit 2 stops the charging operation of the battery 3, the AC generator 20 only needs to have a configuration of power capacity supplied to the load 7. When the power failure detection unit 8 detects a power failure of the AC power supply 10, the power failure detection unit 8 controls the changeover switch circuit 9 to switch from the AC power supply 10 side to the AC generator 20 side and start an engine not shown. The AC generator 20 is driven by the engine. After that, when the power failure detection unit 8 detects the power recovery of the AC power supply 10, the power failure detection unit 8 controls the changeover switch circuit 9 to switch from the AC generator 20 side to the AC power supply 10 side and reset the holding unit 12 of the charging unit 2. Then, the operation of the conversion output unit 11 is restarted, and the charging operation of the battery 3 is started by the electric power from the AC power supply 10. Therefore, it is not necessary to supply a relatively large charging current after time t2 in FIG. 6 (c) as a problem of the conventional example from the AC generator 20, and the AC generator 20 uses the backup power for the load 7 as a backup power. A capacity configuration is sufficient. Since a relatively large charging current in this case is supplied from the AC power supply 10, no problem occurs.

  FIG. 2 is a diagram for explaining the above-described operation, where (a) is the voltage of the AC power supply 10, (b) is the voltage of the AC generator 20, and (c) is input to the main power supply unit 1 and the charging unit 2. Voltage, (d) shows the outline of the charging / discharging current of the battery, and shows the case where the positive side is the charging current and the negative side is the charging current. At time t1, due to a power failure of the AC power supply 10, the voltage becomes zero as shown in (a), the engine is started, and the voltage of the AC generator 20 rises to a predetermined value at time t2. For convenience of explanation, the details of the ascending process and the descending process are not shown. Therefore, the voltage input to the main power supply unit 1 and the charging unit 2 becomes zero during the time t1 to t2, and during this time, the voltage is supplied from the battery 3 to the load 7 as shown in (d). The change in the voltage relationship when the battery 3 is supplied to the load 7 is detected as the start of the backup operation, and the charging operation of the battery 3 is stopped. Further, even if an AC voltage from the AC generator 20 is applied to the charging unit 2, the operation of the conversion output unit 11 of the charging unit 2 is stopped, so that charging of the battery 3 from the charging unit 2 is not performed.

  Next, when the AC power supply 10 recovers at time t3, the AC voltage from the AC power supply 10 is applied to the main power supply unit 1 and the charging unit 2 by the changeover switch circuit 9, and the engine is controlled to stop. Since it is not a sudden stop, the case where the output voltage of the AC generator 20 becomes zero after time t4 is shown. Further, the holding unit 12 of the charging unit 2 is reset by detecting power recovery at time t3, so that the conversion output unit 11 starts operating and starts charging the battery 3. At that time, as in the case of time t2 in FIG. 6 (c), the charging current of the battery 3 is increased, but since the power is supplied from the AC power source 10 having a large power capacity through the charging unit 2, sufficient charging is performed. A current can be supplied.

  FIG. 3 is an explanatory diagram of the second embodiment of the present invention. The same reference numerals as those in FIG. 1 denote the same parts, 22 denotes a comparator, and Vc denotes a comparison voltage. The second embodiment shows a case where a backup operation detecting means is configured by the comparator 22 and the comparison voltage Vc, and an AC voltage is applied from the AC generator 20 to the main power supply unit 1 by starting the engine when the AC power supply 10 is powered down. Until the DC voltage is supplied from the main power supply unit 1 to the load 7, the DC voltage is supplied from the battery 3 to the load 7 via the diode 6, and compared with the forward voltage Vf of the diode 6 in that case. Comparing the voltage Vc with the comparator 22, and when Vc≈Vf, the comparison detection signal of the comparator 22 is input as a backup operation start detection signal to the holding unit 12 constituting the charging stop unit of the charging unit 2. Then, it is held as an operation stop signal of the conversion output unit 11 and the charging operation of the battery 3 is stopped. Therefore, the battery 3 is not charged from the AC generator 20 via the charging unit 2 at the time of a power failure of the AC power supply 10, and the power capacity of the AC generator 20 can be the power capacity supplied to the load 7. it can. When the AC power supply 10 is normal, no current flows through the diode 6, so Vf = 0 and Vc ≠ Vf. Therefore, a DC voltage is supplied from the main power supply unit 1 to the load 7. It can be determined that there is. Further, the operation of the power failure detection unit 8 and the changeover switch circuit 9, the operation in the case of a power failure and power recovery of the AC power supply 10, the operation of the current detection unit 4 and the like are the same as those in the first embodiment, and thus overlap. Description is omitted.

  FIG. 4 is an explanatory diagram of Embodiment 3 of the present invention. The same reference numerals as those in FIG. 1 denote the same parts, and 23 is a current detection unit, which constitutes backup operation detection means. In the third embodiment, the DC voltage from the main power supply unit 1 to the load 7 is based on the AC voltage AC when the AC power supply 10 is normal or the AC voltage AC from the AC generator 20 activated by detecting the power failure of the AC power supply 10. Is detected by the current detector 23, the AC power supply 10 is cut off, and the AC voltage from the AC generator 20 rises in the process of rising, so that current becomes zero. In this case, the detection signal is input to and held in the holding unit 12 of the charging unit 2 constituting the charge stopping unit as a backup operation start detection signal, and is used as the operation stop signal of the conversion output unit 11. Also, the power failure detection unit 8 controls the changeover switch circuit 9 by detecting the power failure of the AC power supply 10 to switch from the AC power supply 10 side to the AC generator 20 side. In addition to switching from the AC generator 20 side to the AC power supply 10 side, the holding unit 12 is reset and the operation of the conversion output unit 11 is restarted. Further, the operation of the power failure detection unit 8 and the changeover switch circuit 9, the operation in the case of a power failure and power recovery of the AC power supply 10, the operation of the current detection unit 4 and the like are the same as those in the first embodiment, and thus overlap. Description is omitted.

  FIG. 5 is an explanatory diagram of a main part of the fourth embodiment of the present invention. The same reference numerals as those in FIG. 1 denote the same parts, 3A denotes a battery unit, 14 denotes a characteristic setting unit, and 15 denotes a characteristic setting input unit. The backup battery is generally replaced after the usable period has elapsed, and is normally replaced with a battery having the same charge / discharge characteristics. In that case, resetting of the charge / discharge characteristics in the charging unit 2 is not necessary. However, the battery may be replaced with a battery having a different charge / discharge characteristic in accordance with the improvement of the backup characteristic. Alternatively, it may be necessary to replace the battery with a new charge / discharge characteristic by stopping production of the battery having the same charge / discharge characteristic as the old battery. As described above, when a battery having a different charge / discharge characteristic is exchanged, it may be necessary to change the setting according to the charge characteristic of the battery by the charging unit 2. Therefore, as the battery unit 3A, a characteristic setting unit 14 indicating charge / discharge characteristic information is provided in the battery unit 3A, a characteristic setting input unit 15 is provided on the charging unit 2 side, and the characteristic setting unit 14 is attached by mounting the battery unit 3A. The charge / discharge characteristic information is read by the characteristic setting input unit 15 and the charge / discharge characteristic is set in the control unit 13. Therefore, it is possible to charge by setting the charging characteristics of the conversion output unit 11 for a new battery simply by mounting the battery unit 3A. Also, the discharge characteristics such as the overdischarge determination voltage of the discharge characteristics are set in the control unit 13, and it is determined whether or not the battery voltage at the time of discharge by the backup operation is an overdischarge state. 5 can be controlled to be turned off to prevent overdischarge.

  The characteristic setting unit 14 and the characteristic setting input unit 15 can be, for example, charging / discharging characteristic information by selecting a plurality of pin contacts, but the battery unit 3A has a charging voltage even if it is not in a fully charged state. Since it is in a state, it is also possible to adopt a configuration in which charging / discharging characteristic information of the characteristic setting unit 14 is transmitted to the characteristic setting input unit 15 when the battery unit 3A is mounted by applying non-contact setting information transmission means. It is. For example, non-contact information transmission means using electromagnetic waves such as RFID can be applied. Therefore, battery replacement can be easily performed even by an operator who does not have knowledge of charge / discharge characteristics, etc., and erroneous setting of the charge / discharge characteristics of a new battery can be reliably prevented, and reliability is maintained. be able to.

It is explanatory drawing of Example 1 of this invention. It is operation | movement explanatory drawing of Example 1 of this invention. It is explanatory drawing of Example 2 of this invention. It is explanatory drawing of Example 3 of this invention. It is explanatory drawing of Example 4 of this invention. It is explanatory drawing of the backup power supply device of a prior art example. It is explanatory drawing of the charging current change of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main power supply part 2 Charging part 3 Battery 4 Current detection part 5 Switch circuit 6 Diode 7 Load 8 Power failure detection part 9 Changeover switch circuit 10 AC power source 11 Conversion output part 12 Holding part 13 Control part 20 AC generator 21, 22 Comparator 23 Current detector

Claims (5)

The AC voltage from the AC power source is converted to a DC voltage and supplied to the load, and the battery is charged by converting the DC voltage to a DC voltage by the charging unit. When the AC power source fails, the engine is started and driven by the engine. In a backup power supply that supplies a DC voltage from the battery to the load through a backflow preventing diode until the AC voltage from the AC generator rises,
Backup operation detection means for detecting whether or not a direct current is supplied from the battery to the load via the diode;
Charge stopping means for holding the detection signal from the backup operation detecting means in a holding unit to stop the charging action of the battery;
A backup power supply apparatus comprising: a power failure detection unit that resets the holding unit upon detection of power recovery of the AC power source after detection of a power failure of the AC power source, and restarts the charging operation of the battery.   The backup operation detection means compares the output voltage of the main power supply unit that converts the AC voltage into a DC voltage and supplies the load to the battery voltage, and starts the backup operation when the battery voltage is high. The backup power supply apparatus according to claim 1, wherein the detected power signal is input to the holding unit.   The backup operation detecting means is configured to input a detection signal for starting a backup operation by detecting a forward voltage drop of the diode when a current is supplied from the battery to the load via the diode. The backup power supply apparatus according to claim 1, further comprising:   The backup operation detection means has a configuration in which a detection signal for converting the AC voltage into a DC voltage and detecting that the current supplied to the load has become zero and starting a backup operation is input to the holding unit. The backup power supply device according to claim 1.   The charging unit includes: a charging control unit that controls charging with a charging characteristic corresponding to the characteristic of the battery; a conversion output unit that is controlled by the charging control unit to charge the battery; and a characteristic setting unit provided in the battery. 2. The backup power supply apparatus according to claim 1, further comprising a characteristic setting input unit that reads setting information when the battery is mounted and inputs the setting information to the charging control unit.

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