JP5672782B2 - Storage device abnormality detection device - Google Patents

Description

  The present invention relates to a detection circuit that detects an abnormality of a power storage device such as a capacitor or a storage battery used in an uninterruptible power supply, a voltage drop countermeasure device, or the like.

  FIG. 6 shows an example of a protection circuit for an electric double layer capacitor (EDLC) unit using a conventional technique. This is the content described in Prior Art Document 1. In the configuration in which the electric double layer capacitor units 1 and 10 in which four electric double layer capacitors are connected in series are connected in parallel, the current detection circuit 3 and the circuit breaker 24 are connected in series with the unit 1, and the current is connected in series with the capacitor unit 10. The detection circuit 30 and the circuit breaker 25 are connected. Reference numeral 5 denotes an equalization circuit for equalizing the voltages of the capacitors.

  With this configuration, the charger unit 2 charges the capacitor units 1 and 10. The currents that flow through each unit at the time of charging and discharging are approximately equal, but when a ground fault or open circuit failure occurs in one unit, the current becomes relatively unbalanced. A configuration in which the unbalance current is extremely small is determined as an open failure, and the circuit breaker 24 or 25 is disconnected by the switching control circuit 4. In this method, since the unit in which the open failure has occurred can be disconnected, the system can be continuously operated with a sound unit.

  Patent document 2 is a prior art for determining the lifetime of the storage battery (battery) used for an uninterruptible power supply. This is a circuit for artificially powering off the AC-DC conversion circuit and determining the life of the storage battery from the discharge current and voltage drop characteristics of the storage battery. When the storage battery is deteriorated, it is a circuit for determining the life by detecting that the internal impedance is increased, the voltage drop is increased, and the rate of decrease is increased as compared with a healthy state.

JP 2002-159135 A Japanese Patent Laid-Open No. 2-55536

  The detection circuit shown in FIG. 6 requires a current detector for detecting the current of each unit. Since the current of each unit flows a large discharge current, there is a problem that the current detector becomes large. In addition, in the fully charged state, only a charging current of about the leakage current flows, so there is a problem that the difference between the current of the unit in which the failure has occurred and the current of the normal unit becomes small, and a reliable failure determination cannot be made. .

Further, the method of Patent Document 2 requires an operation to artificially generate a power failure and discharge from the storage battery, which is a problem from the viewpoint of system reliability.
Therefore, an object of the present invention is to provide a circuit that can determine abnormality of a capacitor, a power storage element, and the like at low cost without deteriorating system reliability.

In order to solve the above-described problem, in the first invention, a power storage device abnormality detection device that detects abnormality of a power storage device in which a plurality of power storage units in which cells such as a plurality of capacitors and storage batteries are connected in series is connected in parallel In accordance with a correctness check command, a charger for charging the power storage device, a charge voltage setting device for setting a charge voltage value of the charger, an overdischarge detection circuit for determining whether the voltage of each cell is correct or not, A charge voltage value changing circuit for changing the charge voltage value to a value lower than that during normal operation, and after the charge voltage value is changed by the charge voltage value changing circuit, the overdischarge detection circuit causes the voltage value of each cell to be excessive. it determines success or failure of the voltage by determining whether below the discharge determination level.

According to a second aspect of the present invention, in the power storage device abnormality detection device for detecting abnormality of a power storage device in which a plurality of power storage units in which cells such as a plurality of capacitors and storage batteries are connected in series are connected in parallel, charging for charging the power storage device A charging voltage setting device for setting a charging voltage value of the charger, an overdischarge detection circuit for determining whether the voltage of the plurality of cell groups is correct, and the charging voltage value based on a correctness check command. A charging voltage value changing circuit that changes the value to a value lower than that during normal operation, and after the charging voltage value is changed by the charging voltage value changing circuit, the overdischarge detection circuit sets the voltage value of each cell to an overdischarge determination level. it determines success or failure of the voltage by determining whether below.

According to a third aspect, in the first or second aspect, the charging voltage value changing circuit is configured to change a setting value of the charging voltage setting device.
According to a fourth aspect, in the first or second aspect, the charging voltage value changing circuit is configured to change a feedback amount of the detected value of the charging voltage.

  In the present invention, as a circuit for determining an abnormality of a power storage device such as a capacitor or a storage battery, the charging voltage of the charger is changed based on a correctness check command, and the voltage of each cell is determined by an overdischarge voltage detection circuit. Judgment is made. As a result, a current detection circuit for measuring the current of each power storage unit is not required, and it is not necessary to generate an artificial power failure. Therefore, a highly reliable storage element abnormality determination circuit can be realized at low cost. .

It is a circuit diagram for explaining a first example of the present invention. It is operation | movement explanatory drawing of FIG. It is a circuit example of an overdischarge detection circuit. It is a circuit diagram for demonstrating the 2nd Example of this invention. It is a circuit diagram for demonstrating the 3rd Example of this invention. It is a circuit diagram for demonstrating a prior art example.

  The gist of the present invention is that as a circuit for determining an abnormality of a power storage device such as a capacitor or a storage battery, the charging voltage of the charger is changed based on the correctness check command, the voltage of each cell is determined by the overdischarge voltage detection circuit, This is the point where the presence or absence of abnormality is determined.

  FIG. 1 shows a first embodiment of the present invention. When the AC power supply Vac is healthy, power is supplied from the AC power supply Vac to the load L via the circuit breaker S1, and when an abnormality such as a voltage drop occurs in the AC power supply Vac, the circuit breaker S1 is opened to store the power storage unit. This is an embodiment of the instantaneous voltage drop compensator that converts the direct current of U1 and U2 into alternating current by the power converter PC and supplies the alternating current to the load L.

  U1 is a power storage unit configured by connecting four capacitor cells (C11 to C14) in series, U2 is a power storage unit configured by connecting four capacitor cells (C21 to C24) in series, and ODD is a lower discharge limit of each capacitor cell. An overdischarge detection circuit for detecting voltage, VR is a DC voltage detector, Vset1 and Vset2 are voltage setting devices, S2 is a changeover switch, and 5 is a voltage equalization circuit.

  In such a configuration, the power converter PC operates as a charger (AC-DC converter) when the AC power source is healthy, and charges the power storage units U1, U2 to a DC voltage set by the voltage setting device Vset1 ( Normal operation). When each cell is normal, the voltage equalizing circuit 5 works to equalize the voltage of each cell.

An operation for detecting a cell failure will be described with reference to FIG. It is an example of a detection operation when there is an open failure in the cell C21 of the power storage unit 2. FIG. 2A shows the operation of the power storage unit U1 in which all the cells are healthy, and FIG. 2B shows the operation of the power storage unit U2 in which the cell C21 has an open failure. When a correct / incorrect check command for detecting an abnormality of each cell is input to the changeover switch S2, the charging voltage is switched from the set value of the setter Vset1 to the set value of Vset2.
2A illustrates the voltage of the power storage unit U1 when the changeover switch S2 is on the Vset1 side as V (U1), and the voltage of the power storage unit U1 when the changeover switch S2 is on the Vset2 side as V (U1) −α. It is the operation when. Although the voltage V (C11) of the cell C11 varies by α / 4, the overdischarge determination level is set to a value lower than this, so the overdischarge detection circuit does not make an abnormality determination.

FIG. 2B illustrates the voltage of the power storage unit U2 when the changeover switch S2 is on the Vset1 side as V (U2), and the voltage of the power storage unit U2 when the changeover switch S2 is on the Vset2 side as V (U2) −α. It is the operation when. Since the cell C21 has an open failure, the voltages of the cells C22 to C24 remain the same as when the changeover switch S2 is on the Vset1 side and do not decrease.
As a result, the voltage V (C21) of the opened cell C21 is expressed by Equation (1).

3 / 4V (U2)-(V (U2) -α) Equation (1)
From this equation, if the charging voltage fluctuation α is appropriately selected, the voltage of the cell C21 that has failed open becomes below the overdischarge determination level as shown in FIG. 2B, and the overdischarge detection circuit ODD detects an open abnormality. can do.

  FIG. 3 is a configuration example of the overdischarge detection circuit ODD. The voltages of the cells (C11 to C14) of the power storage unit U1 are compared with the reference voltages VR11 to VR14 by the comparators CP11 to CP14, respectively, and when one of them falls below the comparison reference value, the output of the NOR circuit NOR1 is high. H ", the output of the OR circuit OR1 becomes high" H ", and an overdischarge detection signal is output. Similarly, the voltages of the cells (C21 to C24) of the power storage unit U2 are compared with the reference voltages VR21 to VR24 by the comparators CP21 to CP24, respectively, and when one of them falls below the reference value, the output of the NOR circuit NOR2 is high. “H”, the output of the OR circuit OR1 becomes high “H”, and an overdischarge detection signal is output.

FIG. 4 shows a second embodiment of the present invention. The difference from the first embodiment is the difference in the circuit configuration that changes the charging voltage in accordance with a correct / incorrect check command. In the present embodiment, there is only one voltage setting device Vset1, and the feedback amount for detecting the output voltage of the charger is increased so that the charging voltage is decreased by α. By short-circuiting the resistor R of the voltage detection circuit configured by the series circuit of the voltage detector VR and the resistor R connected to the DC output of the charger with the switch S3, the detection amount increases and the charging voltage decreases. . The principle and operation of overdischarge detection are the same as in the first embodiment.

  FIG. 5 shows a third embodiment of the present invention. The difference from the first embodiment is the difference in the overdischarge detection circuit. In the first embodiment, the voltage of each cell of the power storage unit is detected and determined. In this embodiment, the voltage in units of a plurality of cells connected in series (in this example, two units) is determined. Detected to determine open abnormality. The principle and operation of overdischarge detection are the same as in the first embodiment. When the number of series-connected cells of the power storage unit is large, the number of electronic components such as a failure determination comparator of the overdischarge detection circuit can be reduced.

  In this embodiment, an example in which four capacitor cells are connected in series has been described. However, even if the number of series increases, an open abnormality can be detected by the same principle. Further, if the number of parallel connection of the power storage units is 2 or more, the detection can be performed by the same principle.

1, 10; capacitor unit 2; charger
3, 30; current detection circuit 4; switching control circuit 5; equalization circuit 6; capacitor 24, 25; circuit breaker Vac; AC power supply L; load S1; circuit breaker PC: power converter S2; Voltage setter ODD; overdischarge detection circuits C11 to C14, C21 to C24; capacitors U1, U2; power storage units CP1 to CP14, CP21 to CP24; comparators VR11 to VR14, VR21 to VR24; reference voltage NOR1, NOR2; NOR circuit OR1; OR circuit R; resistor S3; switch

Claims (4)

In a power storage device abnormality detection device that detects abnormality of a power storage device in which a plurality of power storage units connected in series with a plurality of capacitors, cells such as storage batteries are connected in parallel,
A charger that charges the power storage device; a charging voltage setter that sets a charging voltage value of the charger; an overdischarge detection circuit that determines whether the voltage of each cell is correct; and the charging voltage based on a correctness check command A charge voltage value changing circuit for changing the value to a value lower than that during normal operation, and after the charge voltage value is changed by the charge voltage value changing circuit, the overdischarge detection circuit determines whether the voltage value of each cell is overdischarged. power storage device abnormality detection device characterized that you determine success or failure of the voltage by determining whether below the level. In a power storage device abnormality detection device that detects abnormality of a power storage device in which a plurality of power storage units connected in series with a plurality of capacitors, cells such as storage batteries are connected in parallel,
A charger for charging the power storage device, a charging voltage setting device for setting a charging voltage value of the charger, an overdischarge detection circuit for determining whether the voltage of the plurality of cell groups of the cells is correct, and a correctness check command And a charging voltage value changing circuit that changes the charging voltage value to a value lower than that during normal operation, and the voltage of each cell is changed by the overdischarge detection circuit after the charging voltage value is changed by the charging voltage value changing circuit. power storage device abnormality detection device characterized that you determine success or failure of the voltage by determining whether the value falls below the overdischarge determination level.   The power storage device abnormality detection device according to claim 1, wherein the charging voltage value changing circuit changes a setting value of the charging voltage setting device.   The power storage device abnormality detection device according to claim 1, wherein the charge voltage value change circuit changes a feedback amount of a detection value of the charge voltage.

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