JP5193897B2 - Uninterruptible power supply using electric double layer capacitor - Google Patents

Description

  The present invention relates to an uninterruptible power supply apparatus including an electric double layer capacitor as power storage means that is charged by a charging apparatus when the power supply is in an uninterruptible state.

  Japanese Laid-Open Patent Publication No. 2001-197686 (Patent Document 1) discloses a capacitor uninterruptible power supply device that performs charge / discharge by switching and connecting a capacitor power storage device to an input power supply and a load via charge / discharge control means. This conventional device includes a diagnostic unit that detects the voltage and output current of the capacitor power storage device, obtains the remaining capacity and power consumption, and predicts the operable time and determines the deterioration of the capacitor.

  Japanese Patent Laid-Open No. 2005-168261 (Patent Document 2) stops the converter, discharges electric power from the electric double layer capacitor to the AC load, monitors the voltage and current at that time, and monitors the electric double layer capacitor. Determining deterioration.

JP 2001-197686 A JP 2005-168261 A

  However, in the latter device, the discharge condition (discharge current) of the electric double layer capacitor changes depending on the state of the AC load, and the AC load has many constant power loads. Change. Furthermore, there is a problem that the internal resistance value of the electric double layer capacitor varies depending on the discharge current value. For this reason, it has been difficult to obtain the accuracy of determination of deterioration in the conventional apparatus.

  In particular, when the AC load is small, accuracy cannot be obtained, and a condition of a certain load or more is necessary. In addition, since the electric double layer capacitor is discharged, there is a problem in that the backup time is not guaranteed during a period of charging up to a predetermined voltage (voltage that guarantees the backup time) after the life determination test, which is not safe.

  An object of the present invention is to provide an uninterruptible power supply apparatus using an electric double layer capacitor that can improve the determination accuracy as compared with the prior art and can guarantee the backup time after the end of the life determination test. is there.

  The present invention includes an electric double layer capacitor as a power storage means that is charged by a charging device when the power supply is in a non-power failure state, and further determines the life of the electric double layer capacitor based on capacitance and internal resistance. An uninterruptible power supply device including an electric double layer capacitor provided with the device is an object of improvement.

The lifetime determining device determines a lifetime of the electric double layer capacitor by flowing a constant charging current from the charging device in a predetermined lifetime determining test period T when the power source is in a non-power failure state. For this purpose, the lifetime determination device includes a voltage detector that measures the voltage across the electric double layer capacitor according to a predetermined sequence, an output of the voltage detector, a charging current, and a lifetime determination test period T. A calculation unit that calculates the internal resistance and a life determination unit that determines the life of the electric double layer capacitor based on the calculation result of the calculation unit are provided. Specifically, the voltage detector measures the capacitor voltage Vc0 of the electric double layer capacitor immediately before the charging of the electric double layer capacitor is started using the charging device in the life determination test period, and the electric double layer immediately after the start of charging. The voltage Vc1 of the capacitor or the voltage Vc1 ′ of the electric double layer capacitor immediately before the end of charging is measured, and the capacitor voltage Vc2 of the electric double layer capacitor immediately after the end of the life determination test period is measured. The calculation unit calculates the internal resistance based on the capacitor voltage Vc0, the voltage Vc1 of the electric double layer capacitor immediately after the start of charging, the voltage Vc1 ′ and voltage Vc2 of the double layer capacitor immediately before the end of charging, and the charging current Ic. The capacitance is calculated based on the capacitor voltage Vc0, the charging current Ic, the life determination test period T, and the capacitor voltage Vc2 of the electric double layer capacitor immediately after the end of the life determination test period. For example, the calculation unit obtains the internal resistance R immediately after the start of the life determination test period by an equation of R = (Vc1−Vc0) / Ic or R = (Vc1′−Vc2) / Ic, and calculates the capacitance C0. , C0 = Ic × T / (Vc2−Vc0).

  The electric double layer capacitor uses a normal voltage within the maximum allowable voltage from the viewpoint of life. Therefore, in the present invention, a life determination test is performed in the charging direction of the electric double layer capacitor. Since the internal resistance and the capacitance are obtained based on the capacitor voltage obtained in the process of charging the electric double layer capacitor, it is not affected by the state of the AC load. In addition, since charging can be performed with a constant charging current, the charging condition does not change, and the accuracy of deterioration determination is improved. Since the electric double layer capacitor is not discharged during the life test, it is safe without being affected by the backup time. Furthermore, according to the present invention, the life can be determined even when the AC load is no load.

  In the life determination unit, a method for determining the life from the internal resistance and the capacitance is arbitrary. For example, the determination that the internal resistance R obtained by the calculation unit is greater than or equal to a predetermined reference internal resistance value difference and that the capacitance C0 is equal to or less than the predetermined reference capacitance is determined as a life arrival reference. You may comprise a lifetime determination part.

As a matter of course, it is preferable that the life determination unit generates an alarm signal notifying the arrival of the life when the arrival of the life is determined.

  According to the present invention, the life of an electric double layer capacitor in an uninterruptible power supply provided with an electric double layer capacitor as a power storage means charged by the charging device when the power source is in a non-interruptible state is based on capacitance and internal resistance. It can be expressed as a determination method. According to the method of the present invention, when the power source is in a non-power failure state, a predetermined charging current Ic is allowed to flow from the charging device to the electric double layer capacitor. Within this period T, the voltage across the electric double layer capacitor is measured by a voltage detector according to a predetermined sequence. Then, the capacitance and internal resistance are calculated based on the output of the voltage detector, the charging current Ic, and the lifetime determination test period T, and the lifetime of the electric double layer capacitor is determined based on the calculation result.

It is a figure which shows the structure of embodiment which applied this invention to the uninterruptible power supply device provided with the electric double layer capacitor of a regular commercial power supply type. It is a figure used in order to explain the measurement sequence of a voltage detector. It is a figure which shows the structure of the uninterruptible power supply device provided with the other electric double layer capacitor which can apply this invention. It is a figure which shows the structure of the uninterruptible power supply device provided with the other electric double layer capacitor which can apply this invention. It is a figure which shows the structure of the uninterruptible power supply device provided with the other electric double layer capacitor which can apply this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a configuration of an embodiment in which the present invention is applied to an uninterruptible power supply device equipped with an electric double layer capacitor that is always of a commercial power supply type. In the uninterruptible power supply of FIG. 1, the output from the AC commercial power supply AC is supplied to the AC load L via the AC switch circuit SW when there is no power failure. The bidirectional inverter TINV becomes a charging device composed of an AC / DC converter when there is no power failure, charges the electric double layer capacitor C in accordance with a control signal from the control unit CS, and turns the electric double layer capacitor into a DC power source during a power failure. The bidirectional inverter TINV serves as a DC / AC inverter and supplies AC power to the load L.

  The life determination device 1 includes a voltage detector 2, a calculation unit 3, and a life determination unit 4. The life determination device 1 is controlled to perform a life determination test periodically by the control unit CS. In the life determination test, as shown in FIG. 2, when the power source is in a non-power failure state, a constant length from the bidirectional inverter TINV as the charging device is constant during the life determination test period T of a predetermined length. A charging current Ic is passed through the electric double layer capacitor C.

  The voltage detector 2 measures the voltage across the electric double layer capacitor C (capacitor voltage) according to a predetermined sequence. Specifically, the voltage detector 2 measures the capacitor voltage Vc0 of the electric double layer capacitor C immediately before the charging of the electric double layer capacitor C is started in the life determination test period T, and the electric double layer immediately after the start of charging. The voltage Vc1 of the capacitor C or the voltage Vc1 ′ of the electric double layer capacitor C just before the end of charging is measured, and the capacitor voltage Vc2 of the electric double layer capacitor C just after the end of the life judging test period T is measured.

  The calculation unit 3 calculates the capacitance C0 and the internal resistance R based on the output (Vc0, Vc1 or Vc1 ', Vc2) of the voltage detector 2, the charging current Ic, and the life determination test period T. For example, the calculation unit 3 can calculate the internal resistance R based on the following equation.

R = (Vc1-Vc0) / Ic or R = (Vc1'-Vc2) / Ic
Further, the calculation unit 3 can calculate the capacitance C0 based on the following equation.

C0 = Ic * T / (Vc2-Vc0)
The life determination unit 4 determines the life of the electric double layer capacitor based on the calculation result of the calculation unit 3. In the life determination unit 4, a method for determining the life from the internal resistance R and the capacitance C0 is arbitrary. In the present embodiment, the lifetime is determined so that it is determined that the internal resistance obtained by the calculation unit 3 is greater than or equal to a predetermined reference internal resistance value difference and the capacitance C0 is equal to or less than a predetermined reference capacitance. A determination unit can be configured. The method for obtaining the internal resistance and the capacitance varies depending on the equivalent circuit assumed for the calculation. The above arithmetic expression is based on a simple equivalent circuit in which an internal resistance and a capacitance are connected in series. Also, the method for determining the lifetime can be determined as appropriate according to the equivalent circuit.

  When the life determination unit 4 determines the arrival of the life, the life determination unit 4 generates an alarm signal notifying the arrival of the life. Since the electric double layer capacitor C uses a normal voltage within the maximum allowable voltage from the viewpoint of life, in this embodiment, the life determination test is performed in the charging direction of the electric double layer capacitor C. If a power failure occurs during the test, naturally the AC power is supplied to the load L by using the electric double layer capacitor as a DC power source and the bidirectional inverter as a DC / AC inverter in accordance with a switching command from the control unit CS.

  FIG. 3 shows a configuration of an uninterruptible power supply device including another electric double layer capacitor to which the present invention can be applied. The same constituent members as those shown in FIG. 1 are denoted by the same reference numerals as those shown in FIG. This uninterruptible power supply device is provided with a charging device CHG and an inverter INV separately without using the bidirectional inverter TINV.

  FIG. 4 shows a configuration of an uninterruptible power supply device including still another electric double layer capacitor to which the present invention can be applied. The same constituent members as those shown in FIGS. 1 and 3 are denoted by the same reference numerals as those shown in FIGS. 1 and 3, and the description thereof is omitted. This uninterruptible power supply is a continuous inverter type uninterruptible power supply that supplies an AC power to a load by always operating an inverter during a non-power failure. The output of the AC power supply AC is converted into DC power by the converter CONV, and the electric double layer capacitor C is charged by this DC power, and the inverter INV performs DC / AC conversion.

  Further, FIG. 5 shows a configuration of an uninterruptible power supply device including still another electric double layer capacitor to which the present invention can be applied. In this example, the charging device CHG includes a rectifying circuit that rectifies AC power output from the AC power supply AC into DC power, and performs floating charging of the electric double layer capacitor C. The load L is a DC load. In this example, no inverter is used.

  In any of the uninterruptible power supply devices shown in FIGS. 3 to 5, the life determination device 1 shown in FIG. 1 can be used to determine the life of the electric double layer capacitor C.

  According to the present invention, since the life determination test is performed in the charging direction of the electric double layer capacitor, the internal resistance and the capacitance can be obtained based on the capacitor voltage obtained in the process of charging the electric double layer capacitor, It is not affected by the condition of the AC load. In addition, since charging is performed with a constant charging current, the charging condition does not change, and the accuracy of deterioration determination is improved. Furthermore, since the electric double layer capacitor is not discharged during the life test, it is safe without being affected by the backup time.

DESCRIPTION OF SYMBOLS 1 Life determination apparatus 2 Voltage detector 3 Operation part 4 Life determination part

Claims (2)

Provided with an electric double layer capacitor as power storage means charged by the charging device when the power supply is in a non-power failure state, and further provided with a life determination device for determining the life of the electric double layer capacitor based on capacitance and internal resistance An uninterruptible power supply with an electric double layer capacitor,
The lifetime determination device is configured to increase the lifetime of the electric double layer capacitor when a constant charging current Ic is supplied from the charging device in a predetermined lifetime determination test period T when the power source is in a non-power failure state. In order to determine, based on the voltage detector that measures the voltage across the electric double layer capacitor, the output of the voltage detector, the charging current, and the life determination test period T, the capacitance and the internal A calculation unit that calculates resistance; and a life determination unit that determines the life of the electric double layer capacitor based on a calculation result of the calculation unit;
The voltage detector measures the voltage Vc0 of the electric double layer capacitor immediately before starting charging of the electric double layer capacitor using the charging device during the life determination test period, and the electric detector immediately after the start of charging. Measure the voltage Vc1 of the multilayer capacitor or the voltage Vc1 ′ of the electric double layer capacitor immediately before the end of charging, measure the capacitor voltage Vc2 of the electric double layer capacitor immediately after the end of the life judging test period,
The calculation unit calculates the internal resistance based on the voltage Vc0 and the voltage Vc1 or the voltage Vc1 ′, the voltage Vc2 and the charging current Ic, and the voltage Vc0, the charging current Ic, An uninterruptible power supply comprising an electric double layer capacitor, wherein the electrostatic capacity is calculated based on a test period T for life determination and the voltage Vc2 . The uninterruptible power supply apparatus with the electric double layer capacitor according to claim 1 , wherein when the life determination unit determines the arrival of the life, an alarm signal is generated to notify the arrival of the life.

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