JP2012115103A - Dc power supply and voltage non-equalization suppressing method of capacitor module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a DC power supply with less power consumption and small variation in inter-terminal voltage of a capacitor module.SOLUTION: A voltage non-equalization suppressing circuit 9 is arranged in a capacitor module 5. The voltage non-equalization suppressing circuit 9 includes: a plurality of series circuits 11 composed of normally open switches SW1 to SW5 and resistors R1 to R5, which are connected in parallel to a plurality of capacitors C1 to C5; and a switch control circuit 13. The switch control circuit 13 sets all the normally open switches SW1 to SW5 to a closed state when the capacitor module 5 is charged, and sets the normally open switch of the series circuit connected in parallel to the capacitor having inter-terminal voltage whose differential voltage of the inter-terminal voltage of the capacitor becomes larger than a previously decided allowable range, to the closed state when power is not supplied to a load from the capacitor module 5 to set the differential voltage to be within the allowable range.

Description

  The present invention relates to a DC power supply device including a capacitor module in which a plurality of capacitors are connected in series, and a method for suppressing voltage non-uniformity of the capacitor module.

  There are various types of equipment that can be used for emergency backup, such as UPS, emergency lights, emergency broadcasting equipment, telephone exchanges, and communication equipment base stations. Depending on the required characteristics, various types of power storage such as NiCd, NiMH, and lead batteries The device is being used. As a power source for emergency lighting that is turned on in the event of a fire or power failure, a nickel cadmium battery or a nickel metal hydride battery is generally used, and a lead battery is used in other relatively large capacity facilities. These power storage devices are designed for short-term discharge with a compensation time of about 1 to 30 minutes because it is sufficient to supply power only during the time when people evacuate from the building in the event of an emergency, or during the time of a temporary power failure of the public power supply. Is done.

  In recent years, capacitors are being used instead of batteries for these backup applications. This is because, since a capacitor having a high energy density such as a lithium ion capacitor has been developed, the battery has an advantage over an energy density capacitor under a short-time discharge condition in which the active material utilization rate is extremely reduced. This is because the capacitor has an advantage that it has a longer life than a battery and can be provided with a longer interval between regular replacements.

  The battery charging method in these applications is basically constant-current / constant-voltage charging, and whether to supply power to the load and charge the power storage device separately or by connecting the load and power storage device to the same power source, It can be divided into trickle charge and float charge.

  When using a capacitor, there is a concern that variation between cells due to leakage current becomes large, and a specific capacitor is overcharged or overdischarged. In order to avoid this, in general, a design in which a cell (capacitor) voltage non-uniformity suppression circuit is mounted or the number of cells (capacitors) is increased is adopted. Even in a lead battery, a nickel cadmium battery, etc., variations in voltage between cells (capacitors) occur, but generally there is no problem. This is because there is a timing to charge to near full charge in normal usage, and in these batteries, the higher the charged state of the cell, the more current is consumed in the side reaction gas generation and the charging current efficiency is reduced, resulting in This is because the state of charge between cells becomes uniform.

  Several voltage non-uniformity suppression circuits have been proposed, but the simplest method is to connect resistors and diodes to each cell in parallel (Patent Documents 1 to 3). In order to suppress discharge during standing, it has also been proposed to disconnect a resistor connected in parallel to each cell with a switch during standing. In this case, constant voltage charging such as trickle charging or float charging is usually performed. Moreover, it can also equalize by performing intermittent charge to the capacitor module in which the capacitor series / parallel switching circuit is installed, and connecting the cells in parallel while charging is stopped (Patent Document 4). In Patent Document 4, the charge start timing and the discharge start timing of intermittent charging are defined by a clock. In intermittent charging, the deterioration of the battery can be suppressed by shortening the rate of charging time as much as possible. As control for shortening the charging time, for example, there is a technique (Patent Document 5) in which the charging start timing of intermittent charging is lowered to a predetermined voltage while being left after being fully charged.

Japanese Examined Patent Publication No. 62-4848 (Claim 1) JP 06-302474 A (Claim 1) Japanese Utility Model Laid-Open No. 05-023527 (Claim 1) Japanese Patent No. 3728622 (Claim 1) JP-A-9-117074 (Claim 1)

  In the case of using a capacitor module, if conventional trickle charging or float charging is used, there is a problem that current constantly flows and power is consumed wastefully. When intermittent charging is performed, power consumption is reduced. However, in intermittent charging, since the charging time is short, when a resistor is connected in parallel to each capacitor as an equalization circuit, and the resistor connected only during charging is disconnected by a switch, the voltage variation between the capacitors is large. Accordingly, there is a problem that some capacitors are overdischarged and the lifetime of the capacitors is reduced.

  An object of the present invention is to provide a DC power supply apparatus that solves the above-described problems, consumes less power, and has a small variation in voltage between terminals of a capacitor.

  A direct current power supply device according to the present invention includes a capacitor module in which a plurality of capacitors are connected in series, a power supply that supplies power to a load, and is disposed between the power supply and the capacitor module to intermittently charge the capacitor module; When the supply of power from the power supply to the load is stopped, a charge / discharge circuit that discharges electric charge from the capacitor module to the load and supplies power, and a voltage difference between terminals of a plurality of capacitors within a predetermined allowable range And a voltage non-equalization suppression circuit. The capacitor module is used as a backup power source, for example. The mode of intermittent charging of the capacitor module by the charge / discharge circuit is arbitrary. Charging may be performed when the voltage of the capacitor module falls below a predetermined voltage, or charging operation may be performed periodically.

  In particular, in the present invention, the voltage non-uniformity suppression circuit includes a plurality of series circuits including normally open switches and resistors respectively connected in parallel to a plurality of capacitors, and a switch control circuit. The switch control circuit is connected in parallel to one or more capacitors whose inter-terminal voltage is higher than the inter-terminal voltage of other capacitors by a predetermined allowable range or more when charging the capacitor module. The normally open switch of the connected series circuit is closed, and the normally open switch in the closed state has a difference voltage between the terminal voltage of the one or more capacitors and the terminal voltage of the other capacitor within the allowable range. When the capacitor module is in an uncharged state, all normally open switches are controlled to be open. According to the present invention, a normally-open switch of a series circuit provided for a capacitor whose inter-terminal voltage is higher than an allowable range when compared with the inter-terminal voltage of another capacitor during charging. Is closed and the resistor is connected in parallel to the capacitor. When a resistor is connected in parallel to a capacitor during charging, the rate of increase in voltage between terminals of the capacitor is smaller than the rate of increase in voltage between terminals of other capacitors that are not connected in parallel. As a result, according to the present invention, even when the capacitor module is intermittently charged, variations in the voltage between the terminals of the plurality of capacitors can be reduced in a short time. In addition, a situation in which some capacitors are in an overdischarged state does not occur, and a reduction in the lifetime of the capacitors can be prevented.

  In the present invention, the normally open switch of the series circuit is not closed except during charging. Accordingly, the charge of the capacitor is not self-discharged through the resistor during the non-charging time, and the charge of the capacitor is not discharged through the resistor even during the discharge. The normally open switch may be an electromagnetic switch or a semiconductor switch.

  As a specific switch control circuit, the difference voltage between the terminals of two adjacent capacitors of a plurality of capacitors is obtained, and when it is determined that the difference voltage exceeds the allowable range, the higher voltage between the terminals is determined. A determination circuit that outputs a signal that closes the normally open switch of the series circuit connected in parallel to the capacitor of the capacitor and outputs a signal that opens the normally open switch when the differential voltage is within an allowable range. Things can be used. With such a determination circuit, voltage non-uniformity can be suppressed without using a complicated circuit configuration even when the number of capacitors increases.

  The switch control circuit may include a determination circuit for each of two adjacent capacitors in the plurality of capacitors. Further, one determination circuit may be provided for a plurality of capacitors, and a selection connection circuit for selectively connecting the one determination circuit and two adjacent capacitors of the plurality of capacitors may be provided. With this configuration, the number of determination circuits can be minimized.

  The value of the resistor is determined in consideration of the characteristics and capacitance of the capacitor. When the capacitor is a lithium ion capacitor, the resistance value of the resistor is preferably 10 ± 5Ω.

  The load of the direct current power supply device of the present invention may be an inverter that converts direct current into alternating current. In this case, when the load is included, it becomes an AC power source. The power source used in the DC power supply device of the present invention may be a DC power generator or a power source that rectifies the output of a commercial power source or an AC generator and outputs DC power.

  In other words, the present invention is arranged between a capacitor module in which a plurality of capacitors are connected in series and a power source that supplies power to the load, and intermittently charges the capacitor module and power from the power source to the load. When the supply of power is stopped, voltage unevenness of the capacitor module is suppressed, which suppresses variations in voltage between terminals of a plurality of capacitors included in the capacitor module of the DC power supply device that discharges charges from the capacitor module to the load and supplies power It can be grasped as a method. In the method of the present invention, a plurality of series circuits each including a normally open switch and a resistor are connected in parallel to a plurality of capacitors. When the capacitor module is charged, a series connected in parallel to one or more capacitors of which the inter-terminal voltage is higher than the inter-terminal voltage of other capacitors by a predetermined allowable range or more among the plurality of capacitors. Close the normally open switch of the circuit. After that, when the voltage difference between the terminal voltage of one or more capacitors and the voltage between terminals of other capacitors is within the allowable range, the normally open switch is opened, and in the non-charged state, all normally open switches are opened. To do.

It is a figure which shows the structural example at the time of applying this invention to the DC power supply device for vehicles. (A) And (B) is a figure which shows an example of the determination circuit used with a switch switching circuit. It is a figure which shows the structural example of the power supply system in the case of applying this invention to the uninterruptible power supply for alternating current loads. It is a figure which shows the timing chart of embodiment of FIG.

  FIG. 1 shows a configuration example in the case where the present invention is applied to a DC power supply device 1 used as a normal vehicle power supply having no plug-in travel function. In this DC power supply device 1, since a commercial AC power supply cannot be used, the DC generator 3 is used as a power supply for supplying power to the charger of the capacitor module 5 and the load L. The DC generator 3 has a structure in which the output of an engine generator that generates power by moving the engine with fuel is rectified and output. As the DC generator 3, one that generates electric power using the brake regenerative energy of the engine generator can be used.

  The capacitor module 5 has a structure in which a plurality of capacitors C1 to C5 are connected in series. In the present embodiment, the capacitor module 5 is used as a backup power source. The number of capacitors is arbitrarily determined according to the required voltage. When the capacitors C1 to C5 of the capacitor module 5 are intermittently charged between the DC generator 3 and the capacitor module and the supply of power from the DC generator 3 to the load L is stopped, the capacitor module 5 receives the load L A charge / discharge circuit 7 for discharging electric charges to supply electric power is disposed. The mode of intermittent charging of the capacitor module 5 by the charge / discharge circuit 7 is arbitrary. In the present embodiment, charging starts when the inter-terminal voltage of the capacitor module 5 becomes equal to or lower than a predetermined voltage, and stops charging when the inter-terminal voltage of the capacitor module 5 reaches a predetermined upper limit voltage. The charging / discharging circuit 7 is configured to perform charging in the charging mode. Here, the predetermined voltage is determined in consideration of using the capacitor module 5 as a backup power source. For example, 80% of the rated voltage of the capacitor module 5 can be set to a predetermined voltage. The upper limit voltage can be determined as a voltage that is 100% of the rated voltage.

  The decrease in the voltage between the terminals of the capacitor module 5 is detected by a voltage detector (not shown) provided inside the charge / discharge circuit 7. A voltage detector (not shown) detects a voltage drop and charging completion by comparing the voltage across the capacitor module 5 with a reference voltage and an upper limit voltage.

  Moreover, in this Embodiment, the voltage non-equalization suppression circuit 9 for suppressing generation | occurrence | production of the variation in the voltage between the terminals of the some capacitors C1-C5 during charge is provided. The voltage non-uniformity suppression circuit 9 includes a plurality of series circuits 11 including normally open switches SW1 to SW5 and resistors R1 to R5 connected in parallel to a plurality of capacitors C1 to C5, respectively, and a switch control circuit 13. Composed. When the charge / discharge circuit 7 charges the capacitors C <b> 1 to C <b> 5 of the capacitor module 5, the switch control circuit 13 has a terminal voltage among the plurality of capacitors higher than a predetermined allowable range than the power between terminals of other capacitors. The normally open switch of the series circuit 11 connected in parallel to the one or more capacitors is closed. That is, during charging, the normally open switches (SW1 to SW5) of the series circuit provided for the capacitor having a relatively high inter-terminal voltage as compared with the inter-terminal voltage of other capacitors are closed, and the resistor ( R1-R5) are connected in parallel to capacitors C1-C5. When the normally open switches (SW1 to SW5) are closed, the resistor is connected in parallel to the capacitor, and the amount of charge to the capacitor to which the resistor is connected in parallel decreases. Therefore, the rising speed of the inter-terminal voltage of the capacitor having the resistor connected in parallel is slower than the rising speed of the inter-terminal voltage of the other capacitor not connected to the resistor. As a result, variation in the voltage between terminals is suppressed during charging. When the difference voltage between the terminal voltage of one or more capacitors and the voltage between the terminals of other capacitors becomes a voltage within an allowable range, the switch control circuit 13 opens the normally open switch that is closed. As a result, when the variation in the voltage between the terminals is suppressed during charging, the resistor is disconnected from the capacitor, and thereafter the capacitor is charged with the same charge amount (voltage increase rate) as other capacitors. Therefore, according to the present embodiment, even when the capacitor module is intermittently charged, the variation in the voltage between the terminals of the plurality of capacitors can be reduced in a short time. As a result, a situation in which some of the capacitors are in an overdischarge state does not occur, and a reduction in the lifetime of the capacitors can be prevented.

  Note that a method for detecting a capacitor whose terminal voltage is higher than a predetermined allowable range than the terminal voltage of other capacitors is arbitrary.

  In the present embodiment, the normally open switches SW1 to SW5 are not closed except during charging.

  Specifically, in the present embodiment, when the switch control circuit 13 is not supplying power from the capacitor module 5 to the load L, the switch control circuit 13 detects the voltage difference between the terminals of the plurality of capacitors C1 to C5 and detects the difference. The normally open switches (SW1 to SW5) of the series circuit 11 connected in parallel to a capacitor having a voltage between terminals whose voltage is greater than a predetermined allowable range are closed, and the differential voltage is within the allowable range. In the present embodiment, a voltage difference between terminals of two adjacent capacitors (C1, C2, C2, C3,... C4 and C5) among a plurality of capacitors C1 to C5 is detected. Then, the normally open switches (SW1 to SW5) of the series circuit connected in parallel to the capacitors having the inter-terminal voltage whose differential voltage is outside the predetermined allowable range are closed, and the terminals of the plurality of capacitors C1 to C5 are closed. The voltage difference between the voltages is within a predetermined allowable range. When the differential voltage is within the allowable range, the normally open switches (SW1 to SW5) that are in the closed state are opened. In the present embodiment, the allowable range is a voltage range of ± 1% of the inter-terminal voltage of a reference capacitor (one capacitor of two capacitors for which a differential voltage is obtained).

  2A and 2B are arranged in the switch control circuit 13, and when the voltage difference between the terminals of the capacitors C1 and C2 is outside a predetermined allowable range (± 1%), A conduction signal for closing the normally open switch SW1 or SW2 connected in parallel to the capacitor having a higher voltage between the terminals is output, and the normally open switch SW1 or SW2 that is in a closed state when the differential voltage falls within an allowable range. 3 shows an example of a determination circuit having a function of opening the. In the determination circuit of FIG. 2A, the resistance value is set so that the resistance r1 and the resistance r2 have a relationship of r2 = 0.99 × r1. In the determination circuit of FIG. 2B, the resistance value is set so as to satisfy the relationship r2 = 1.01 × r1. As a result, the aforementioned allowable range ± 1% is set. In the determination circuit of FIG. 2A, when the voltage (V2-V1) between terminals of the capacitor C1 is 0.01% or more higher than the voltage (V3-V2) between terminals of the capacitor C2, a conduction signal is supplied to the switch SW1. Is output. This conduction signal continues to be output until the voltage difference between the terminal voltage (V2-V1) of the capacitor C1 and the terminal voltage (V3-V2) of the capacitor C2 becomes smaller than 0.01%. As a result, a part of the charge that the resistor R1 was supposed to be charged in the capacitor C1 is discharged, and the voltages of the two capacitors C1 and C2 are equalized (inhibition of variations in the voltage between terminals). Further, in the determination circuit of FIG. 2B, when the voltage (V3-V2) between terminals of the capacitor C2 is 0.01% or more higher than the voltage (V2-V1) between terminals of the capacitor C1, the switch SW2 is turned on. A signal (switch-on signal) is output. This conduction signal continues to be output until the voltage difference between the terminal voltage (V3-V2) of the capacitor C2 and the terminal voltage (V2-V1) of the capacitor C1 becomes smaller than 0.01%. The presence of the resistor R2 limits the amount of charge of the capacitor C2, and equalizes the voltage between the terminals of the capacitor C2 and the voltage between other terminals of the capacitor C2 (suppresses variation in the voltage between the terminals). . 2A and 2B stops the output of the continuity signal when the differential voltage is within the allowable range (the switch off signal is output to close the normally open switch). The normally open switch SW1 or SW2 in the closed state is opened.

  The switch control circuit 13 includes the same circuit as the determination circuit shown in FIGS. 2A and 2B for two adjacent capacitors. The determination circuit in FIG. 2 is an example, and it is needless to say that a determination circuit having another circuit configuration can be used. For example, one determination circuit may be provided for a plurality of capacitors, and a selective connection circuit that selectively connects the one determination circuit and two adjacent capacitors of the plurality of capacitors may be provided. With this configuration, the number of determination circuits can be minimized.

  When the capacitor module 5 is applied to a DC power supply device as in the above embodiment, it is desirable to separately install a battery for dark current backup. In this case, the generator for charging can be switched so that either the capacitor or the battery can be selected, or the capacitor and the battery can be connected in parallel to enable charging. Cost increase and equipment enlargement due to the installation of the vessel can be avoided.

  The DC power supply device of the present invention may be applied to an uninterruptible power supply for DC loads. In this case, since it is an uninterruptible power supply, a public AC power supply and an AC-DC converter are used as a charger. The DC power supply device can also be applied to an uninterruptible power supply for AC loads. In this case, an inverter may be disposed between the capacitor module shown in FIG. In general, since the inverter has a low conversion efficiency of about 90%, if the load can be used with a public AC power supply, the public AC power supply and the load may be directly connected without using the inverter except in an emergency.

  When the DC power supply device of the present invention is applied to a power source of a vehicle having a plug-in travel function, it is preferable to add a regenerative charging function in addition to the plug-in travel function. In order to add a regenerative charging function, a converter with a regenerative function that can regenerate a regenerative current to the power source side may be used as an inverter.

  When the voltage non-equalization suppression circuit 9 is used as in the present embodiment, the power consumed by the voltage non-equalization suppression circuit 9 may also be a problem. It is desirable to provide a function for stopping the operation. In the embodiment of FIG. 1, the consumption in the voltage non-uniformity suppression circuit 9 is reduced by reducing the sensitivity of the voltage non-equalization suppression circuit 9 by widening the above-described allowable range (± 1%) in the switch control circuit 13. Electric power can be reduced.

  A specific example of another embodiment of the present invention for an uninterruptible power supply (UPS) will be described below with reference to FIG. Also in this embodiment, as in the embodiment of FIG. 1, when the variation in the voltage between terminals of the plurality of capacitors C is large at the start of charging, the voltage between the terminals is higher than the voltage between the terminals of other capacitors. The normally open switch SW of the capacitor in the voltage non-equalization suppression circuit 29 that has become larger than the allowable range is closed, and equalization processing is performed. In this embodiment, a load for a 12V DC power source is assumed as the load L. As the capacitor module 25 of the produced uninterruptible DC power supply, a single cell having a rated 3.7V1000F lithium ion capacitor connected in series was used. As the AC-DC converter 23 for converting the trademark power supply AC into a direct current, one having a voltage of 13.8 V and a current of 10 A was used.

When the voltage across the capacitor module 25 becomes 14.8V or less, or when the voltage across the terminals of the four capacitors C exceeds a predetermined allowable range, the voltage non-uniformity suppression circuit 29 is It was set as a condition to start. When the switch control circuit 33 in the voltage non-uniformity suppression circuit 29 detects that the maximum value−minimum value ≧ 0.05 V of the voltage across the terminals of each capacitor C, 10 A, 14.8 V constant current constant voltage charging is performed. A command to start charging under the condition of is output to the charging / discharging circuit 27, and 14.8V is maintained for 3 hours in a state where the maximum value-minimum value <0.05V between the terminals of each capacitor C, A command to end is output to the charge / discharge circuit 27.
A timing chart in this case is shown in FIG. During charging stop and discharging, the normally-open switch SW is in the open state, so that the voltage non-uniformity suppression circuit 29 is disconnected, and during that time, the variation between the terminals of the capacitor C is expanded due to the self-discharge current variation between cells. To do. In FIG. 4, when intermittent charging is started, charging current flows through the plurality of capacitors C. The terminal voltage (module voltage) of the capacitor module 25 begins to rise. At this time, the voltage between the terminals of the plurality of capacitors C varies, and the capacitor C whose terminal voltage is higher than the allowable range among the plurality of capacitors C is correspondingly opened from the switch control circuit 33. A conduction signal for closing the switch SW is output. A “switch-on signal” in FIG. 4 indicates a conduction signal output from the switch control circuit 33 to the normally open switch SW. When the module voltage reaches the upper limit voltage and a predetermined time elapses, charging is stopped. In FIG. 4, the switch-off period is a period during which charging is stopped. During this period, the normally open switch SW is in an open state, the capacitor module 25 performs self-discharge, and the module voltage decreases. When the module voltage drops to a predetermined reference voltage, intermittent charging is started again.

  In FIG. 4, the period during which the current flows in the negative direction is the discharge period, and the current during this period is the discharge current. When the discharge current flows, the module voltage decreases, so that intermittent charging is started as soon as the discharge ends.

  ADVANTAGE OF THE INVENTION According to this invention, when the switch control circuit charges a capacitor module intermittently with a charging / discharging circuit, the dispersion | variation in the voltage between the terminals of a some capacitor can be made small. As a result, a situation in which a part of the capacitors is in an overdischarged state does not occur, and an advantage that a reduction in the lifetime of the capacitors can be prevented can be obtained.

DESCRIPTION OF SYMBOLS 1 DC power supply device 3 DC generator 5,25 Capacitor module 7,27 Charge / discharge circuit 9,29 Voltage non-equalization suppression circuit 11 Series circuit 13,33 Switch control circuit L Load C, C1-C5 Capacitor SW, SW1-SW5 Normally open switch R, R1-R5 resistor

Claims (5)

A capacitor module in which a plurality of capacitors are connected in series;
A power source for supplying power to the load;
When the capacitor module is intermittently charged between the power supply and the capacitor module and the supply of power from the power supply to the load is stopped, the charge is discharged from the capacitor module to the load. A charge / discharge circuit for supplying
A voltage non-uniformity suppressing circuit for suppressing variations in voltage between terminals of the plurality of capacitors,
The voltage non-equalization suppression circuit is
A plurality of series circuits each including a normally open switch and a resistor connected in parallel to the plurality of capacitors;
When charging the capacitor module, among the plurality of capacitors, the inter-terminal voltage is connected in parallel to one or more of the capacitors whose terminal voltage is higher than a predetermined allowable range than the inter-terminal voltage of the other capacitors. The normally open switch of the series circuit is closed, and the normally open switch in the closed state has a voltage difference between the terminal voltage of the one or more capacitors and the terminal voltage of the other capacitor within the allowable range. A DC power supply device comprising: a switch control circuit that is opened when a voltage is reached and that opens all the normally open switches when the capacitor module is in a non-charged state. The switch control circuit obtains a voltage difference between terminals of two adjacent capacitors of the plurality of capacitors, and determines that the voltage difference exceeds the allowable range. Outputting a signal to close the normally open switch of the series circuit connected in parallel to the higher capacitor;
2. The DC power supply device according to claim 1, further comprising a determination circuit that outputs a signal for opening the normally open switch when the difference voltage falls within the allowable range.   The DC power supply device according to claim 2, wherein the switch control circuit includes the determination circuit for each of two adjacent capacitors in the plurality of capacitors.   The DC power supply device according to claim 1, wherein the capacitor is a lithium ion capacitor, and the resistance value of the resistor is a value within a range of 10 ± 5Ω. When the capacitor module is arranged between a capacitor module in which a plurality of capacitors are connected in series and a power source for supplying power to the load to intermittently charge the capacitor module and the supply of power from the power source to the load is stopped, A method for suppressing voltage non-uniformity of a capacitor module that suppresses variations in voltage between terminals of a plurality of capacitors included in the capacitor module of a DC power supply device that supplies electric power by discharging electric charge from the capacitor module to the load. And
A plurality of series circuits composed of normally open switches and resistors are connected in parallel to the plurality of capacitors,
When charging the capacitor module, the terminals are connected in parallel to one or more of the plurality of capacitors whose terminal voltage is higher than the terminal voltage of other capacitors by a predetermined allowable range or more. When the normally open switch of the series circuit is closed, and then the voltage difference between the terminals of the one or more capacitors and the terminals of the other capacitors becomes a voltage within the allowable range, the normally open switch A method for suppressing voltage non-uniformization of a capacitor module, characterized in that, in a non-charged state, all the normally open switches are opened.

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