JP2007312558A - Discharger and power supply system using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a discharger, along with a power supply system using the same, which effectively uses capability of a power supply while avoiding variation in capacitance drops between parallel power supplies, to supply power. <P>SOLUTION: The power supply system supplies a DC power which a nickel hydrogen storage battery 1 outputs to a load 4 through a step-up circuit 2 and a step-down circuit 3 in this order. When the voltage of a nickel hydrogen storage battery 1 fluctuates between 7th setvalue V<SB>7</SB>and 8th set value V<SB>8</SB>, a switching element 8 of the step-up circuit 2 operates so that the output voltage of the step-up circuit 2 does not drop beyond 9th setvalue V<SB>9</SB>which is higher than V<SB>7</SB>but lower than V<SB>8</SB>, while a switching element 9 of the step-down circuit 3 operates so that the output voltage of the step-down circuit 3 does not exceed 10th setvalue V<SB>10</SB>which is higher than V<SB>7</SB>but lower than V<SB>8</SB>and higher than V<SB>9</SB>. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a discharger and a power supply system using the same, and more particularly to a discharger for supplying power output from a DC power supply to a load and a power supply system using the same.

  Nickel metal hydride storage batteries have a higher energy density than lead storage batteries and are characterized by long battery life and low environmental impact. Since it is lightweight, compact and convenient to carry, it has been rapidly spreading in recent years as an in-vehicle battery and a disaster countermeasure power source.

  When using a nickel-metal hydride storage battery as a power source, for example, one unit (average voltage 1.2 V, capacity 95 Ah) of 10 units called a single cell is used as one unit (hereinafter referred to as one module), and four modules are used. Two connected in series are used in parallel.

Patent Documents 1, 2, and 3 listed below describe a power supply device that includes a plurality of assembled batteries, a charge control unit, and a discharge control unit. Patent Document 1 describes the assembly based on the manufacturing date of the assembled battery. It is described that the battery usable period is calculated and the assembled battery replacement date is displayed, and Patent Document 2 describes that a battery monitoring unit for performing a discharge capacity test of the assembled battery is provided, and Patent Document 3 describes It is described that the battery monitoring means calculates the remaining capacity of the assembled battery and determines the auxiliary charging time of the assembled battery based on the result.
JP 2004-119112 A JP 2004-120856 A JP 2004-120857 A

  In order to cope with the recent increase in power demand of communication facilities, for example, a nickel-metal hydride storage battery system with an output of 30 kWh is required in order to increase the capacity by connecting battery series in parallel. In such a system, for example, 10 cells with a rating of 1.2 V are connected in series, this is taken as 1 module, and 4 modules are further connected in series, making this 1 system (corresponding to the following assembled battery), and 6 systems. Mount. Furthermore, a charger for performing intermittent charging, a discharger for keeping the battery voltage within the allowable voltage range of the load, and a control unit are provided. FIG. 5 shows a configuration diagram of the system.

  In FIG. 5, the plurality of assembled batteries 10 are charged by the output of the rectifier 11 via the charger 12, and supply power to the load 14 via the plurality of dischargers 13. The plurality of dischargers 13 are electrically connected at their output points, and the system can be expanded by adding the dischargers 13 and the assembled battery 10.

  The discharger 13 performs step-down by a converter when the battery voltage exceeds the allowable voltage range of the load (step-down mode), and bypasses the battery output without passing through the converter (bypass mode) when within the allowable voltage range. When the voltage is lower than the value, the voltage is boosted by the converter (boost mode).

  Furthermore, a 100 kWh class system can be realized by realizing the 30 kWh system described above and paralleling three such systems.

  However, in this 30 kWh nickel-metal hydride storage battery system, since the three dischargers 13 make determinations of boosting, bypassing, and stepping down, slight capacity variations of the assembled batteries 10 of each system cause the output voltage of the discharger 13 to A difference appears, and the timing at which the discharger 13 switches from the step-down mode to the bypass mode is different. Since the output voltage of the discharger 13 that has entered the bypass mode first becomes higher than the output voltage of the other dischargers 13 that are still in the step-down mode, much of the power supply to the load 14 is released before entering the bypass mode first. The electric appliance 13 is responsible. Therefore, the capacity of the battery line under the discharger 13 that has entered the bypass mode earlier is significantly lower than the others. After the series of the discharger 13 is disconnected first, the remaining series becomes heavy and exceeds the output capacity, so the remaining series is also disconnected, and as a result, a part of the dischargeable energy stored in the battery remains. As a result, power supply to the load is stopped, the time during which power can be supplied to the load at the time of a power failure is shortened, and it becomes necessary to add an extra storage battery, resulting in a problem of increasing the installation space and the cost for system construction.

  In order to avoid a shift in mode switching timing between the dischargers, it is possible to perform control so that the timing of the transition from step-down to bypass and from bypass to step-up is performed simultaneously for all the dischargers. This is a method of giving a transition command to all the dischargers on the system when a predetermined voltage value is reached while monitoring the battery voltage and the load voltage. This method can eliminate the shift in the timing of transition, but in a system in which the dischargers are configured in parallel, a communication line is laid between the dischargers and a logic control circuit for performing simultaneous control is added. Therefore, there is a problem that the cost increases and a failure rate increases due to the addition of a logic control circuit for performing simultaneous control.

  Note that the timing of transition between the operation modes is shifted, and as a result, the problem that the discharge of the system stops while leaving the remaining capacity of the battery is not limited to the case of the nickel metal hydride storage battery system, such as a lithium ion battery. A secondary battery system that has a plurality of assembled batteries formed by combining secondary batteries and supplies the power output from the assembled battery to a load via a plurality of converters, and further includes a plurality of batteries including a primary battery. A battery system that supplies power output from a plurality of assembled batteries to a load via a plurality of converters, and further includes a plurality of DC power supplies including a power storage capacitor. This is a problem that also occurs in a power supply system that supplies power output from the power supply to a load via a plurality of converters.

  The present invention has been made in view of the above-described problem that the timing of transition between operation modes is shifted, and as a result, the discharge of the system stops while leaving the remaining capacity of the battery. An object of the present invention is to provide a discharger that supplies power while avoiding variations in capacity reduction between parallel power supplies and effectively utilizing the power supply capability, and a power supply system using the same.

In order to solve the above problem, in the present invention, as described in claim 1,
In the discharger comprising a reactor, a diode, a capacitor, and a switching element, and having a booster circuit that boosts or directly outputs DC power, and outputs the input DC power via the booster circuit, When the voltage of the electric power fluctuates between the first set value and the second set value, the output voltage of the booster circuit is larger than the first set value and smaller than the second set value. The discharge element is configured such that the switching element operates so as not to fall below a set value.

In the present invention, as described in claim 2,
A discharger comprising a reactor, a diode, a capacitor, and a switching element, and having a step-down circuit that steps down or directly outputs DC power, and outputs the input DC power through the step-down circuit. When the voltage of the power fluctuates between the fourth set value and the fifth set value, the output voltage of the step-down circuit is larger than the fourth set value and smaller than the fifth set value. The discharge element is configured such that the switching element operates so as not to exceed a set value.

In the present invention, as described in claim 3,
Consists of a reactor, a diode, a capacitor, and a switching element, and includes a booster circuit that boosts or outputs DC power, and a reactor, a diode, a capacitor, and a switching element, and steps down DC power or as it is And a step-down circuit that outputs the input DC power to the step-up circuit, and outputs the power output from the step-up circuit through the step-down circuit. So that the output voltage of the booster circuit does not fall below the ninth set value that is larger than the seventh set value and smaller than the eighth set value. And the switching element of the booster circuit operates, and the output voltage of the step-down circuit is larger than the seventh set value and smaller than the eighth set value. , Constitutes a discharger, wherein the switching elements of the ninth step-down circuit so as not to exceed the greater tenth set value than the set value of the works.

In the present invention, as described in claim 4,
Consists of a reactor, a diode, a capacitor, and a switching element, and includes a step-down circuit that steps down DC power or outputs it as it is, and a reactor, a diode, a capacitor, and a switching element, boosts DC power, or And a step-up circuit that outputs the input DC power to the step-down circuit and outputs the electric power output from the step-down circuit through the step-up circuit. So that the output voltage of the step-down circuit does not exceed the thirteenth set value that is greater than the eleventh set value and smaller than the twelfth set value. The switching element of the step-down circuit operates, and the output voltage of the step-up circuit is greater than the eleventh set value and the twelfth set value. It is small, and constitutes a discharger, wherein the switching elements of the first 13 the boosting circuit so as not to fall below the lower 14th set value than the set value of the works.

In the present invention, as described in claim 5,
In the step-up circuit, the positive input terminal is connected to the first end of the reactor, and the second end of the reactor is connected to the positive side via the diode whose forward direction is from the input side to the output side. Connected to the output terminal, the negative input terminal is connected to the negative output terminal via a conductor, the second end of the reactor is connected to the conductor via the switching element, and the positive output terminal is connected to the capacitor. To the negative output terminal, and in the step-down circuit, the positive input terminal is connected to the first end of the switching element, and the second end of the switching element is connected to the positive output terminal via the reactor. The negative input terminal is connected to the negative output terminal by a conductive wire, and the second end of the switching element is connected to the conductive wire via the diode with the direction from the positive side to the negative side being the reverse direction. It continued, and the positive output terminal is characterized in that connected to the negative output terminal through the capacitor, constituting a discharger according to any one of claims 1 to 4.

In the present invention, as described in claim 6,
6. The discharger according to claim 1, wherein the discharger includes a DC power supply and a discharger, and supplies DC power output from the DC power supply to a load via the discharger. The power supply system characterized by the above is configured.

In the present invention, as described in claim 7,
The power supply system according to claim 6, wherein the DC power supply is a battery.

In the present invention, as described in claim 8,
The power supply system according to claim 7, wherein the battery is a secondary battery.

In the present invention, as described in claim 9,
A rectifier, a plurality of chargers, a plurality of battery packs, and a plurality of dischargers, wherein the battery pack is charged by the output of the rectifier through the charger and to the load through the discharger In the power supply system which supplies electric power, the said discharger is the discharger in any one of Claim 1 thru | or 5, and comprises the power supply system characterized by the above-mentioned.

In the present invention, as described in claim 10,
The power supply system according to claim 8 or 9, wherein the secondary battery or the assembled battery is a nickel metal hydride storage battery.

  By configuring the discharge device according to claim 1, 2, 3, 4 or 5, or the power supply system according to claim 6, 7, 8, 9 or 10, variation in capacity reduction between parallel power sources can be reduced. Thus, it is possible to provide a discharger that supplies power while effectively utilizing the capability of the power supply and a power supply system using the same.

  That is, when the discharger according to the present invention is configured in parallel, the output voltage is continuous at the time of mode switching (when switching from the step-down operation to the bypass operation, or from the bypass operation to the step-up operation), Even if the switching timing differs between the dischargers, if the DC power supply has a finite discharge capacity, the output voltage continuously changes without increasing. The timing of switching naturally aligns in a direction that balances the ability between electrical appliances. A current does not concentrate on a specific discharger, and a large discharge current is shared by a DC power supply having a large discharge remaining capacity. As the discharge progresses, the discharge discharge capacity of each DC power supply naturally becomes equal. After that, the remaining capacity of each DC power supply decreases with the same remaining capacity, and all the DC power supplies reach the discharge end voltage at the same time and the discharge stops, so that all the dischargeable energy stored in the DC power supply is loaded. Supplied to.

  In addition, since the discharge control is performed without applying an external signal line, it is easy to extend the system in parallel.

(Example of booster circuit)
An example of a booster circuit in a discharger according to the present invention is shown in FIG. In the figure, DC power is input to the booster circuit from the left side and output from the right side of the booster circuit. The booster circuit includes a reactor 5, a capacitor 6, a diode 7, and a switching element 8 (represented as a field effect transistor). The positive input terminal is connected to the first end of the reactor 5, and the second end of the reactor 5 is , Connected to the positive output terminal via a diode 7 whose forward direction is from the input side to the output side, the negative input terminal is connected to the negative output terminal by a conducting wire, and the second end of the reactor 5 is The switching element 8 is connected to the conducting wire, and the positive output terminal is connected to the negative output terminal via the capacitor 6.

The step-up operation is performed by the switching element 8 periodically repeating the on-off operation. When the ON time in one cycle of the ON-OFF operation in the switching element 8 is T _ON and the OFF time is T _OFF , the output voltage _VOUT of the booster circuit is (1 + T _ON / T _OFF ) of the input voltage _VIN of the booster circuit. Doubled and boosted.

  If the switching element 8 is kept off, the booster circuit outputs the input power as it is. In this case, since the booster circuit performs an operation equivalent to the bypass operation, this operation is simply referred to as a bypass operation.

In the booster circuit shown in FIG. 1, when the input voltage _{V IN} is varied at the first set value _{V 1} or the second set value _{V 2} less, increase the output voltage _{V OUT} of the step-up circuit, than _{V 1} V _The switching element 8 operates so as not to fall below the third set value V ₃ smaller than ₂ .

When a plurality of combinations of a DC power source having the same set values V ₁ and V ₂ and the above-described discharger having the same set value V ₃ are used in parallel connection, different sets have different times. be shifted from the bypass operation to the step-up operation, the output voltage V _OUT is only maintained at a voltage V ₃ at the operation proceeds time, no current is concentrated on particular discharger, DC power Co. In the case of having the discharge capacity, the power supply from the DC power supply via the discharger naturally shifts in the direction in which the remaining discharge capacity of each DC power supply becomes equal.

  In a power supply system having a DC power supply and a discharger and supplying DC power output from the DC power supply to a load via the discharger, the discharger is shown in FIG. A power supply system characterized by being a discharger having a booster circuit that operates can be configured.

(Example of step-down circuit)
An example of the step-down circuit in the discharger according to the present invention is shown in FIG. In the figure, DC power is input to the step-down circuit from the left side and output from the right side of the step-down circuit. The step-down circuit includes a reactor 5, a capacitor 6, a diode 7, and a switching element 9 (represented as a field effect transistor). A positive input terminal is connected to a first end of the switching element 9. The end is connected to the positive output terminal via the reactor 5, the negative input terminal is connected to the negative output terminal by a conducting wire, and the second end of the switching element is reverse in the direction from the positive side to the negative side The positive output terminal is connected to the negative output terminal via the capacitor 6.

The step-down operation is performed by the switching element 9 periodically repeating the on-off operation. On the switching element 9 - OFF operation one cycle of the on time _{T ON,} if the off-time _{T OFF,} the output voltage _{V OUT} of the step-down circuit _{T ON} / _{(T ON} + _T of the input voltage _{V IN} of the step-down circuit _OFF ), and the voltage is reduced.

  If the switching element 9 is kept on, the step-down circuit outputs the input power as it is. In this case, since the step-down circuit performs an operation equivalent to the bypass operation, this operation is simply referred to as a bypass operation.

In the step-down circuit shown in FIG. 2, when the input voltage _{V IN} is varied in the fifth set value _{V 5} following the fourth set value _{V 4} higher, the output voltage _{V OUT,} even greater than _{V 5} than _{V 4} small sixth switching element 9 so as not to exceed the set value V ₆ of works.

When a plurality of combinations of DC power sources having the same set values V ₄ and V ₅ and the above-described dischargers having the same set value V ₆ are used in parallel, different sets are used at different times. also shifts from the step-down operation to the bypass operation, since the output voltage V _OUT only decreases continuously from the voltage V ₆ at operation transition time, no current is concentrated on particular discharger, DC power Co. In the case of having the discharge capacity, the power supply from the DC power supply via the discharger naturally shifts in the direction in which the remaining discharge capacity of each DC power supply becomes equal.

  In a power supply system having a DC power supply and a discharger and supplying DC power output from the DC power supply to a load via the discharger, the discharger is shown in FIG. A power supply system characterized by being a discharger having a step-down circuit that operates can be configured.

(Example of discharger)
An example of a discharger according to the present invention is shown in FIG. In the figure, the discharger has a step-up circuit 2 and a step-down circuit 3. The DC power output from the nickel metal hydride storage battery 1 is input to the step-up circuit 2, and the power output from the step-up circuit 2 is passed through the step-down circuit 3. Supply to load 4.

  The configuration of the step-up circuit 2 is the same as the configuration of the step-up circuit shown in FIG. 1, and the configuration of the step-down circuit 3 is the same as the configuration of the step-down circuit shown in FIG.

  When this discharger performs the boosting operation, the switching element 9 is kept on, the step-down circuit 3 is in the bypass operation state, and the boosting circuit 2 performs the boosting operation by the on / off operation of the switching element 8.

  When this discharger performs a step-down operation, the switching element 8 remains off, the step-up circuit 2 enters a bypass operation state, and the step-down circuit 3 performs a step-down operation by the on / off operation of the switching element 9.

  When the discharger performs a bypass operation, the switching element 8 is kept off and the switching element 9 is kept on.

  Note that under the following operating conditions, the switching element 8 and the switching element 9 do not simultaneously turn on and off.

In the discharge device shown in FIG. 3, when the voltage of the input voltage V _IN That nickel-metal hydride storage battery 1 fluctuates below the seventh set value V ₇ or 8 of the set value V _8, the output voltage V _M of the booster circuit 2 but the switching element 8 so as not to fall below the ninth set value V ₉ smaller than larger V ₈ than V ₇ is operated.

In the discharger shown in FIG. 3, the output voltage V _OUT of the step-down circuit 3 does not exceed the tenth set value V ₁₀ which is larger than V ₇ but smaller than V ₈ and larger than V _9. Then, the switching element 9 operates.

By the operation of the switching elements 8 and 9 as described above, the output voltage V _OUT of the discharger becomes V ₉ or more and V ₁₀ or less, and is constant or continuously decreased as the remaining discharge capacity of the nickel metal hydride storage battery 1 decreases. , Never rise.

When a plurality of combinations of nickel hydride storage batteries 1 having the same set values V ₇ and V ₈ and the above dischargers having the same set values V ₉ and V ₁₀ are used in parallel connection, different sets are used. to different times, the transition from the step-down operation to the bypass operation, or even subjected to transition from the bypass operation to the step-up operation, the output voltage V _OUT in a voltage range of V ₉ or V ₁₀ or less, to increase Therefore, the current does not concentrate on a specific discharger, and the power supply to the load 4 naturally shifts in the direction in which the discharge remaining capacities of the nickel hydride storage batteries 1 become equal.

  In a power supply system having a DC power supply and a discharger and supplying DC power output from the DC power supply to a load via the discharger, the discharger is shown in FIG. A power supply system characterized by being a discharger that performs the above-described operation can be configured. FIG. 3 shows a power supply system in which the DC power supply is a nickel metal hydride storage battery 1.

  In such a power supply system, the output voltage of the discharger at the time of transition between operations becomes continuous, the above-mentioned problem in the power supply system in which a plurality of dischargers are configured in parallel, that is, the timing of transition between operations is shifted, and as a result As described above, the problem that the discharge of the system stops while leaving the remaining capacity of the battery is solved.

(Other examples of discharger)
The booster circuit 2 and the step-down circuit 3 in FIG. Such a configuration is shown in FIG. Of the description of the discharger shown in FIG. 4, the same part as the description of the discharger shown in FIG. 3 is omitted.

In the discharge device shown in FIG. 4, when the voltage of the input voltage V _IN That nickel-metal hydride storage battery 1 fluctuates twelfth set value V ₁₂ inclusive set value V ₁₁ of the first 11, the output voltage V _M of the step-down circuit 3 _but the switching element 9 so as not to exceed the set value _{V 13} of the smaller 13 than larger _{V 12} than _{V 11} is operated.

Further, in the discharge device shown in FIG. 4, the output voltage _{V OUT} of the step-up circuit 2 is _smaller than larger _{V 12} than _{V 11, and,} so as not to fall below the 14th set value _{V 14} is smaller than _{V 13} Then, the switching element 8 operates.

The operation of the switching elements 8 and 9 as described above, the output voltage V _OUT of the discharge vessel becomes V ₁₄ or V ₁₃ or less, with a decrease in the discharge remaining capacity of the nickel-hydrogen storage battery 1, constant either, or continuously decreases , Never rise.

Different sets are used when a plurality of combinations of the nickel hydride storage battery 1 having the same set values V ₁₁ and V ₁₂ and the above discharger having the same set values V ₁₃ and V ₁₄ are connected in parallel. to different times, the transition from the step-down operation to the bypass operation, or even subjected to transition from the bypass operation to the step-up operation, the output voltage V _OUT in a voltage range of V ₁₄ or V ₁₃ or less, to increase Therefore, the current does not concentrate on a specific discharger, and the power supply to the load 4 naturally shifts in the direction in which the discharge remaining capacities of the nickel hydride storage batteries 1 become equal.

  In a power supply system having a DC power supply and a discharger and supplying DC power output from the DC power supply to a load via the discharger, the discharger is shown in FIG. A power supply system characterized by being a discharger that performs the above-described operation can be configured. FIG. 4 shows a power supply system in which the DC power supply is a nickel metal hydride storage battery 1.

  In such a power supply system, the output voltage of the discharger at the time of transition between operations becomes continuous, the above-mentioned problem in the power supply system in which a plurality of dischargers are configured in parallel, that is, the timing of transition between operations is shifted, and as a result As described above, the problem that the discharge of the system stops while leaving the remaining capacity of the battery is solved.

  As described above, the embodiment of the present invention has been described by taking the case where the DC power source is a nickel hydride storage battery as an example, but the present invention is not limited to this.

  In general, in the power supply system illustrated in FIG. 5, it is possible to configure a power supply system characterized in that the discharger is a discharger according to the present invention. That is, it has a rectifier, a plurality of chargers, a plurality of assembled batteries, and a plurality of dischargers, and the assembled batteries are charged by the output of the rectifier through the chargers, and through the dischargers In the power supply system for supplying power to a load, the power discharge system according to the present invention can be configured as the discharger.

  Below, the effect produced by this invention is demonstrated.

  (1) In a system configured in parallel at the discharger output point, when there is a capacity deviation between battery series, the timing to enter step-down or step-up differs depending on the discharger. Therefore, due to the output voltage discontinuity when switching the mode of the discharger, The current concentrates on the discharger having the battery series with a small capacity, and the remaining battery series has a surplus power at the end of the discharge.

  According to the present invention, when the discharge devices are configured in parallel, the output voltage of the discharge devices is continuous at the time of mode switching. Therefore, even if the switching timing differs between the discharge devices, the DC power supply has a finite discharge capacity. Since the output voltage continuously changes without increasing, excessive discharge due to the increase of the output voltage does not occur, and the switching timing is naturally aligned in the direction of balancing the capabilities between the dischargers. The current does not concentrate on a specific discharger, and a large discharge current is shared by the DC power supply having a large discharge remaining capacity, so that the remaining discharge capacities of each series are naturally aligned. It is possible to effectively draw out the power supply capacity and increase the system capacity by the parallel configuration.

  (2) The addition of simultaneous control for operating a plurality of dischargers at the same time increases the cost for adding a logic control circuit for performing simultaneous control, and logic control for performing simultaneous control. There is a problem that the failure rate increases due to the addition of circuits.

  According to the present invention, since the discharge control is performed without applying an external signal line, it is easy to extend the system in parallel.

  (3) In the method of forcibly switching the electric circuit and the operation mode while measuring the battery voltage and the load voltage, the output voltage fluctuation at the time of mode switching is unavoidable, and this causes a sudden load fluctuation between the parallel dischargers, The power supply to the load equipment may become unstable.

  In the present invention, the method of forcibly switching the electric circuit by measuring the battery voltage or the load voltage is not used, so there is no voltage fluctuation at the time of switching. Since the output voltage at the time of mode transition does not rise or fall, there is no sudden fluctuation of the load between the parallel dischargers. Therefore, the power supply quality of the power supply to the load facility is improved.

It is a figure which shows an example of the step-up circuit in the discharger which concerns on this invention. It is a figure which shows an example of the pressure | voltage fall circuit in the discharger which concerns on this invention. It is a figure which shows an example of the discharger which concerns on this invention. It is a figure which shows the other example of the discharger which concerns on this invention. It is a block diagram of the battery system using a some assembled battery and a some discharger.

Explanation of symbols

1: nickel hydride storage battery, 2: booster circuit, 3: step-down circuit, 4: load, 5: reactor, 6: capacitor, 7: diode, 8, 9: switching element, 10: battery pack, 11: rectifier, 12: Charger, 13: Discharger.

Claims (10)

In a discharger comprising a reactor, a diode, a capacitor, and a switching element, having a booster circuit that boosts DC power or outputs the DC power as it is, and that outputs the input DC power via the booster circuit,
When the voltage of the DC power fluctuates between a first set value and a second set value, an output voltage of the booster circuit is larger than the first set value and smaller than the second set value. A discharger in which the switching element operates so as not to fall below a set value of 3. In a discharger that consists of a reactor, a diode, a capacitor, and a switching element, has a step-down circuit that steps down DC power or outputs it as it is, and outputs input DC power through the step-down circuit.
When the voltage of the DC power fluctuates between the fourth set value and the fifth set value, the output voltage of the step-down circuit is larger than the fourth set value and smaller than the fifth set value. The discharge element is characterized in that the switching element operates so as not to exceed a set value of 6. Consists of a reactor, a diode, a capacitor, and a switching element, and includes a booster circuit that boosts or outputs DC power, and a reactor, a diode, a capacitor, and a switching element, and steps down DC power or as it is In a discharger having an output voltage step-down circuit, inputting input DC power to the step-up circuit, and outputting electric power output from the step-up circuit through the step-down circuit,
When the voltage of the DC power fluctuates between the seventh set value and the eighth set value,
The switching element of the booster circuit operates so that the output voltage of the booster circuit does not fall below a ninth set value that is larger than the seventh set value and smaller than the eighth set value,
The step-down circuit so that the output voltage of the step-down circuit is larger than the seventh set value and smaller than the eighth set value and does not exceed the tenth set value larger than the ninth set value. A discharger in which a switching element of a circuit operates. Consists of a reactor, a diode, a capacitor, and a switching element, and includes a step-down circuit that steps down DC power or outputs it as it is, and a reactor, a diode, a capacitor, and a switching element, boosts DC power, or In a discharger having a booster circuit for outputting, inputting input DC power to the step-down circuit, and outputting power output from the step-down circuit via the step-up circuit,
When the voltage of the DC power fluctuates between the eleventh set value and the twelfth set value,
The switching element of the step-down circuit operates so that the output voltage of the step-down circuit does not exceed the thirteenth set value that is larger than the eleventh set value and smaller than the twelfth set value,
The boosting voltage is set so that an output voltage of the boosting circuit does not fall below a fourteenth set value that is larger than the eleventh set value and smaller than the twelfth set value and smaller than the thirteenth set value. A discharger in which a switching element of a circuit operates. In the step-up circuit, the positive input terminal is connected to the first end of the reactor, and the second end of the reactor is connected to the positive side via the diode whose forward direction is from the input side to the output side. Connected to the output terminal, the negative input terminal is connected to the negative output terminal via a conductor, the second end of the reactor is connected to the conductor via the switching element, and the positive output terminal is connected to the capacitor. Connect to the negative output terminal
In the step-down circuit, the positive input terminal is connected to the first end of the switching element, the second end of the switching element is connected to the positive output terminal via the reactor, and the negative input terminal is a conductor. To the negative output terminal, the second end of the switching element is connected to the conductor via the diode with the direction from the positive side to the negative side being the reverse direction, and the positive output terminal is the capacitor The discharger according to any one of claims 1 to 4, wherein the discharger is connected to a negative output terminal via a terminal. In a power supply system having a DC power supply and a discharger, and supplying DC power output from the DC power supply to a load via the discharger,
A power supply system, wherein the discharger is the discharger according to any one of claims 1 to 5.   The power supply system according to claim 6, wherein the DC power supply is a battery.   The power supply system according to claim 7, wherein the battery is a secondary battery. A rectifier, a plurality of chargers, a plurality of battery packs, and a plurality of dischargers, wherein the battery pack is charged by the output of the rectifier through the charger and to the load through the discharger In a power supply system that supplies power,
A power supply system, wherein the discharger is the discharger according to any one of claims 1 to 5.   The power supply system according to claim 8 or 9, wherein the secondary battery or the assembled battery is a nickel metal hydride storage battery.

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