JP2010252552A - Discharger, discharging method, and dc power system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a discharger which eliminates variation in discharge current between the systems connected in parallel, and efficiently utilizes the discharge capacity of a DC power supply during discharge, and to provide a discharging method and a DC power system. <P>SOLUTION: In the DC power system, battery packs 1a-1b are provided. Outputs of the battery packs 1a-1b are connected to dischargers 2a-2b, respectively. The dischargers 2a-2b are connected in parallel at the outputs to supply power to a load 4. The dischargers 2a-2b are provided with a means for measuring the input voltage, a means for measuring the output terminal voltage, and a means for setting the output voltage value. If the output terminal voltage is equal to or higher than a second predetermined voltage when the input voltage reaches a first predetermined voltage during power output and thereby power output is stopped by the dischargers 2a-2b, the output voltage set value is autonomously reduced. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a discharger, a discharge method, and a DC power supply system.

  Generally, in a DC power supply system that supplies power to a DC load device, a rectifier that receives commercial AC power and outputs DC power such as DC 48V is used. Furthermore, in order to maintain the power supply to the DC load device even when the commercial AC power fails, a backup battery system is provided with a storage battery and a charger for charging the storage battery at the output of the rectifier. The storage battery is an assembled battery connected in series so as to correspond to the operating voltage of the DC load device. However, since the voltage of the storage battery fluctuates due to charging and discharging, the voltage of the assembled battery does not match the input voltage range of the DC load device. Sometimes. For this reason, a discharger is inserted between the assembled battery and the DC load device, and the supply voltage is kept within an allowable range by performing step-up or step-down.

  Patent Documents 1 and 2 below describe a power supply system that supplies power output from a plurality of assembled batteries to a load via a discharger. Patent Document 1 discloses that the output voltage of the booster circuit falls below a set value V9. It is described that the switching element of the step-down circuit operates so that the output voltage of the step-down circuit does not exceed the set value V10. Patent Document 2 discloses a discharge stop signal, an input When either a voltage drop or overvoltage output is detected, the discharge to the load is stopped, and when the discharge stop signal is reset or the input voltage is restored, the discharge to the load is resumed. It is described that not only the output side but also the manual switch operation can be supplied from the discharger input side, and that the switching element is kept open during a power failure of the control unit.

JP 2007-31558 A JP 2008-092768 A

  FIG. 4 is a configuration diagram of a DC power supply system including a rectifier, a plurality of assembled batteries, a charger, and a discharger. In the figure, the assembled battery 1 (simply indicated by the assembled battery 1 when any of the six assembled batteries is not specified) includes 40 nickel-metal hydride storage cells (rated voltage 1.2 V, rated capacity 100 Ah). The battery packs are connected in series, and the battery packs 1a to 1f are mounted on each of the six systems (systems 1 to 6). Dischargers 2a-2f and chargers 3a-3f are connected to the assembled batteries 1a-1f, respectively. The rectifier 5 converts the power input from the AC power source 6 into DC power, outputs DC power of a predetermined voltage (for example, 51 V), and supplies the DC power to the load 4. The chargers 3a to 3f convert the power input from the AC power source 6 into DC power and charge the assembled batteries 1a to 1f, respectively. The discharge voltages of the dischargers 2a to 2f are set to a predetermined voltage (for example, 50V). Six systems of the dischargers 2a to 2f are connected in parallel at the output point, and are further connected in parallel to the electric circuit from the rectifier 5 to the load 4.

  In this DC power supply system, when the AC power supply 6 is valid, the power output from the rectifier 5 is supplied to the load 4, and the assembled batteries 1a to 1f are charged by the chargers 3a to 3f, respectively. When the AC power supply 6 is out of power, the electric power discharged from the assembled batteries 1a to 1f is supplied to the load 4 via the dischargers 2a to 2f, respectively.

  The six dischargers 2a to 2f have the same specifications, but due to output voltage errors and differences in wiring resistance from the discharger output point to the parallel connection point (difference in wiring diameter and wiring length) Dispersion of discharge current occurs.

  Even if the assembled batteries 1a to 1f of all the systems are charged equally before the start of discharge, the unevenness of the discharge current is inevitable. Therefore, the assembled battery 1 of the system where the current is most concentrated is ahead of the other systems. When the discharge end voltage is reached, the discharge stops. Thereafter, since the discharge output shared by the remaining systems increases, the shared discharge output is the output of the discharger 2 (indicated simply by the discharger 2 if any of the six dischargers is not specified). When the capacity is exceeded, the discharging operation of the entire system stops.

  As a result, power supply to the load 4 is stopped while a part of the dischargeable energy accumulated in the six systems of assembled batteries 1a to 1f remains, so that the load 4 is not damaged when the AC power supply 6 is powered off. This will shorten the time that power can be supplied. Therefore, it becomes necessary to add an extra storage battery, that is, the assembled battery 1, and a problem arises that the installation space for the DC power supply system and the cost required for construction increase.

  In order to eliminate the uneven discharge current, there is a method of measuring the discharge current of each system and adjusting the output current of the dischargers 2a to 2f. However, a separate control device is required. Since it is necessary to lay a communication line, another problem such as an increase in cost and a decrease in reliability occurs. In order to solve this problem, it is necessary for each system to perform discharge control independently and to suppress current bias.

  This problem is a problem that can occur not only in a system using a nickel metal hydride storage battery but also in a DC power supply system such as a system using another secondary battery or a primary battery, an electric double layer capacitor, or a fuel cell.

  As described above, the present invention has the problem that the discharge of the system stops while leaving the remaining capacity of the discharge capacity due to the output voltage error between the parallel dischargers and the wiring resistance difference from the discharger output point to the parallel connection point. The problem to be solved by the present invention is to eliminate variations in discharge current between systems connected in parallel and to fully utilize the discharge capability of a DC power supply during discharge. An object is to provide a discharger, a discharge method, and a DC power supply system.

In order to solve the above problems, the present invention provides a method as described in claim 1.
In a discharger that inputs DC power and steps down or boosts and outputs the power, it comprises means for measuring the input voltage, means for measuring the output terminal voltage, and means for setting the output voltage value, and is outputting power The output is stopped when the input voltage decreases to a predetermined first voltage or when the output power exceeds the output capacity.

In the present invention, as described in claim 2,
When the output terminal voltage is equal to or higher than a predetermined second voltage at the time when the input voltage decreases during power output and reaches the first voltage or when the output power exceeds the output capacity and the output stops. The output voltage setting value is reduced, and when the output voltage reaches the first voltage during power output and reaches the first voltage or when the output power exceeds the output capacity and the output stops, the output terminal voltage is 2. The discharger according to claim 1, wherein when the voltage is less than the second voltage, at least one of the control for increasing the output voltage set value is autonomously performed.

In the present invention, as described in claim 3,
In a discharger that receives DC power and steps down or boosts the output
A means for measuring an input voltage; a means for measuring an output terminal voltage; a means for setting an output voltage value; and a time measuring means. An output is stopped when the voltage is reached or when the output power exceeds the output capacity.

In the present invention, as described in claim 4,
The time from when the input voltage decreases during power output and reaches the first voltage or when the output power exceeds the output capacity and the output stops until the output terminal voltage becomes less than the predetermined second voltage. measured T _oN, when the measured T _oN is a first time or more predetermined, and controlled to lower the output voltage set value, the case measured T _oN is less than a predetermined second time Further, at least one of the control for increasing the output voltage set value is autonomously performed, and the discharger according to claim 3 is configured.

In the present invention, as described in claim 5,
5. The discharger according to claim 1, wherein the DC power output from the storage battery is used as an input.

In the present invention, as described in claim 6,
DC power is input, stepped down or boosted and output, and means for measuring the input voltage and means for measuring the output terminal voltage are provided. A discharge method using a discharger that stops output when a voltage is reached or when output power exceeds an output capacity, the input voltage of the discharger being reduced during power output of the discharger, and When the output voltage is equal to or higher than a predetermined second voltage when the first voltage is reached or the output power of the discharger exceeds the output capacity and the output of the discharger is stopped, the discharge is performed. A control for lowering the set value of the output voltage of the electric device, and during the power output of the discharger, the input voltage of the discharger decreases to reach the first voltage or the output power of the discharger exceeds the output capacity. When the output of the discharger stops, the output terminal voltage is If it is less than the second voltage, constituting the discharge method characterized by performing at least one of the control of the control to raise the output voltage set value of dissipating collector.

In the present invention, as described in claim 7,
DC power is input, stepped down or boosted and output to measure the input voltage, output terminal voltage measuring means, and time measuring means, and the input voltage is reduced during power output. A discharge method using a discharger that stops output when a predetermined first voltage is reached or when output power exceeds an output capacity,
From the time when the input voltage of the discharger decreases and reaches the first voltage during the power output of the discharger, or when the output power of the discharger exceeds the output capacity and the discharger stops the output. The time T _ON until the output terminal voltage becomes less than the predetermined second voltage is measured, and when the measured T _ON is equal to or longer than the predetermined first time, the control for lowering the output voltage set value; When the measured _TON is less than a predetermined second time, at least one of control for increasing the output voltage set value is performed.

In the present invention, as described in claim 8,
DC power is input, stepped down or boosted and output to measure the input voltage, output terminal voltage measuring means, and time measuring means, and the input voltage is reduced during power output. A discharge method in which a plurality of dischargers that stop outputting when a predetermined first voltage is reached or when output power exceeds an output capacity are connected in parallel, and each of the dischargers includes the discharger The output terminal voltage from the time when the input voltage of the discharger decreases and reaches the first voltage during the power output of the output or when the output power of the discharger exceeds the output capacity and the discharger stops the output. There is corresponding to dissipating collector to measure the time T _oN until less than a predetermined second voltage, the output voltage set value of each of the discharger, T _oN or more T _oN corresponding to dissipating Electric The output voltage setting value of the discharger corresponding to Sea urchin, it constitutes a discharge method comprising for setting the output voltage.

In the present invention, as described in claim 9,
9. The discharge method according to claim 6, 7 or 8, wherein the discharger receives DC power output from a storage battery as an input.

In the present invention, as described in claim 10,
There are provided a plurality of assembled batteries in which one or more storage batteries are connected in series, and a discharger is connected to the output of each of the assembled batteries, and the plurality of dischargers are connected in parallel at the output to supply power to the load. In the DC power supply system to supply
A DC power supply system is characterized in that the discharger is the discharger according to any one of claims 1 to 5.

  According to the discharger, the discharge method, and the DC power supply system of the present invention, the DC power supply can be discharged by changing the output voltage setting value at the next discharge according to the transition of the discharge operation of each system during the discharge. Since it is possible to use up a lot of energy, it is possible to reduce the number of direct-current power supplies to be installed, thereby saving cost and space.

It is a figure explaining the example of an embodiment of the invention. It is a figure which shows transition of the voltage of a battery system at the time of discharge, and discharge current. It is a flowchart explaining the discharge control of this invention. It is a block diagram of the direct-current power supply system which consists of a rectifier, a some assembled battery, a charger, and a discharger. It is a flowchart explaining the discharge control of this invention. It is a flowchart explaining the discharge control of this invention.

  In the present invention, in the system where the discharge current is concentrated, the discharger output voltage is set to be lowered at the next discharge, and in the system where the discharge current is small, the discharger output voltage is set to be raised at the next discharge. A discharger and a DC power supply system in which the discharger is connected to each of the parallel power supply systems are configured.

  Hereinafter, the case where the discharger according to the present invention is applied to a DC power supply system using a nickel-metal hydride storage battery as a DC power supply will be described as an example, but the present invention is not limited to this. Further, although the description will be made assuming that the discharger steps down and outputs the input DC power, the present invention is also applied to a discharger that steps up and outputs the input DC power.

  FIG. 1 is a diagram for explaining an embodiment of the present invention.

  In FIG. 1, an assembled battery 1 (indicated simply by the assembled battery 1 when one of the two assembled batteries is not specified), a discharger 2 (simply released when one of the two dischargers is not specified). The case where the discharge system comprised from 2) is shown is shown.

  In the DC power supply system of FIG. 1, a rectifier 5 (output voltage is 52 V) that converts AC power input from the AC power supply 6 to DC power and two systems of dischargers 2 a to 2 b are connected in parallel to supply power to the load 4. It is carried out.

  The assembled battery 1 is an assembled battery (rated voltage 72 V, rated capacity 100 Ah) in which 60 cells of nickel hydride storage batteries (rated voltage 1.2 V, rated capacity 100 Ah) are connected in series.

  Each of the dischargers 2a to 2b includes a converter that steps down the power input from each of the assembled batteries 1a to 1b and outputs it to the load 4. Further, the dischargers 2a to 2b include means for measuring the input voltage, means for measuring the output terminal voltage, means for setting the output voltage value, and time measuring means. When executing A1 and A2, no time measuring means is required.

  The load 4 is a load that operates with DC power, such as a communication device, and the upper limit of the allowable voltage is 53V.

  The chargers 3a to 3b charge the connected assembled batteries 1a to 1b, respectively. The assembled battery 1 reaches 90V when fully charged, and the end-of-discharge voltage is 60V. For this reason, the discharger 2 steps down the supply voltage to the load 4 to 50V. However, as will be described later, this output voltage is finely adjusted by a control method for suppressing discharge current variation, which is a feature of the present invention. Further, the discharger 2 has a function of stopping the discharge by interrupting the input when the input voltage reaches 60 V (the discharge end voltage of the assembled battery 1) in order to prevent the assembled battery 1 from being overdischarged. In addition, it has a function of stopping output when the output power exceeds the output capacity.

  In this DC power supply system, when the AC power supply 6 is effective, the power output from the rectifier 5 is supplied to the load 4, and when the AC power supply 6 is out of power, the power output from the assembled batteries 1a to 1b is discharged to the discharger 2a. Supplied to load 4 via ~ 2b.

  When the AC power supply 6 is in a power failure, the power output from the assembled batteries 1a to 1b is supplied to the load 4 through the dischargers 2a to 2b, respectively, but the discharge current assigned to each system is charged before the power failure. Variations occur depending on the state. Further, variations occur due to an output voltage error between the parallel dischargers 2a to 2b and a wiring resistance difference from the discharger output point to the parallel connection point. For this reason, when the discharge is started due to a power failure, the discharge proceeds in a state where the discharge current is biased, and in the discharge system where the current is concentrated, the discharge is stopped early, and the above-described problem occurs. For example, as shown in the transition of the output voltage and current of each system in FIG. 2, the output voltage of system 1 is slightly higher, so the burden of output current is greater than system 2, and system 1 stops discharging first. Thereafter, power is supplied to the load 4 by only the second system.

  Therefore, in the present invention, each discharger 2 detects the output voltage of the other system discharger 2 that appears on the output side even after its own system has stopped discharging, and the next discharge is performed according to its temporal transition. The output voltage setting is changed at, thereby suppressing power concentration.

  The discharger (for example, 2a) cuts off the input and stops the output when the voltage of the assembled battery 1a, which is the input voltage, reaches the final discharge voltage 60V or when the output power exceeds the output capacity. To do. Further, the output side voltage that is the output terminal voltage is monitored thereafter.

  Here, since the outputs of the dischargers 2a to 2b are electrically connected at the connection point, if the other discharger (here 2b) is still outputting, the output of its own discharger (here 2a) Since a voltage is applied to the end, it can be detected that the discharger 2b is discharging.

  In this embodiment, at least one of the following control methods is performed.

(Control method A1)
While the discharger (for example, 2a) is discharging, the input voltage reaches a predetermined first voltage V1 (for example, 60V which is the discharge end voltage of the assembled battery 1) or the output power exceeds the output capacity and is output. At the time when the discharge is stopped, the output terminal voltage of the discharger 2a is equal to or higher than a predetermined second voltage V2 (for example, 48V, a value lower than the output voltage when at least one of the dischargers 2a to 2b is discharging). If so, it indicates that the other discharger (here 2b) has left the discharge capacity and is supplying power to the load 4, so the discharger 2a autonomously sets its output voltage setting value. Control to lower. As a result, in the next discharge, the discharger 2a continues to discharge for a longer time, and the variation in the remaining discharge capacity becomes smaller.

(Control method A2)
Further, if the output terminal voltage of the discharger 2a is less than the second voltage V2 at the time when the discharger 2a stops outputting in the same manner as described above, the other discharger (here 2b) is connected to the discharger 2a. Since this indicates that the output was stopped earlier than before, the discharger 2a performs control to autonomously increase its output voltage set value. Thereby, in the next discharge, the discharger 2b continues to discharge for a longer time, and the variation in the remaining discharge capacity becomes smaller.

  In the control methods A1 and A2, time measurement is not necessary.

(Control method B1)
Each of the dischargers 2a to 2b includes a time measuring means.

While the discharger (for example, 2a) is discharging, the input voltage reaches a predetermined first voltage V1 (for example, 60V that is the discharge end voltage of the assembled battery 1) or the output power exceeds the output capacity. When the output terminal voltage of the discharger 2a is equal to or higher than the second voltage V2 (for example, 48V) at the time when the output is stopped, the time during which the output terminal voltage is maintained at V2 or higher ( _TON ) is measured. It shall be.

  Finally, the discharge is stopped in all the other discharge systems, and the voltage on the output side becomes less than the second voltage V2. Therefore, the time measurement thereafter is stopped.

Discharger 2a, the measurement result of the time T _ON to full lineage discharge stop from the own system is a discharge stop (output voltage second less than the voltage V2) becomes the predetermined first time T1 When it is (for example, 10 minutes) or more, the output voltage set value at the next discharge is autonomously lowered by ΔV (for example, 0.1 V). In the example of FIG. 2, the time from when the 1 system stops discharging until the entire system stops discharging is 1.75 hours, so the output voltage setting value of the 1 system discharger 2a is lowered by 0.1V. . As a result, in the next discharge, the discharger 2a continues to discharge for a longer time, and the variation in the remaining discharge capacity becomes smaller.

The above control of the dischargers 2a to 2b (control method B1) can be expressed by, for example, the flowchart shown in FIG. 3 (in the figure, the second voltage V2 and the first time T1 are V ₂ , T ₁ ).

In FIG. 3, for example, the output voltage of the battery pack 1a of the system 1 reaches a predetermined first voltage V1 (for example, 60V which is the discharge end voltage of the battery pack 1) or the output power exceeds the output capacity and the output of the system 1 If the output terminal voltage (V _out ) of the discharger 2b is equal to or higher than the second voltage (V ₂ ) at step 21 (represented by S21, the same applies hereinafter) Go to step 22; otherwise, go to step 24. In step 22, time Δt (here, 1 second) is added to the time (T _ON ) in which the output terminal voltage (V _out ) of the discharger 2 b is equal to or higher than the second voltage (V ₂ ), and the process proceeds to step 23. Note that _TON is reset to zero at the starting point. In step 23, the process waits for time Δt and returns to step 21. If it is determined in step 24 that T _ON is _equal to or longer than the first time (T ₁ ), the process proceeds to step 25; otherwise, the control is terminated. In step 25, the discharger 2a autonomously lowers its own output voltage set value by ΔV (for example, 0.1V) and ends the control.

  By performing such discharge control (control method B1) autonomously at each discharge, in each system where the discharge current is concentrated, the output voltage of the discharger 2 of that system decreases in the next discharge. Therefore, the burden on the discharge current is reduced, and current variations are suppressed. Furthermore, since this discharge control is independently performed by the dischargers 2a to 2b of each system, it is not necessary to provide a separate control unit.

  A second embodiment with six discharge systems will be described with reference to FIG.

  In the DC power supply system shown in FIG. 4, a rectifier 5 (output voltage is 52 V, for example) that converts AC power input from the AC power supply 6 into DC power, and six systems of dischargers 2a to 2f are connected in parallel, and the load 4 Is supplying electricity.

  The assembled batteries 1a to 1f are assembled batteries (rated voltage 72V, rated capacity 100Ah) in which 60 nickel-metal hydride storage battery cells (rated voltage 1.2V, rated capacity 100Ah) are connected in series.

  The dischargers 2a to 2f include a converter that steps down the power input from the assembled batteries 1a to 1f and outputs the voltage to the load 4. Furthermore, the dischargers 2a to 2f include means for measuring the input voltage, means for measuring the output terminal voltage, means for setting the output voltage value, and time measuring means. When carrying out A1 and A2, no time measuring means is required.

  The load 4 is a load that operates with DC power, such as a communication device, and the upper limit of the allowable voltage is, for example, 53V.

  The chargers 3a to 3f charge the connected assembled batteries 1a to 1f. The assembled batteries 1a to 1f reach a voltage of 90V when fully charged, and the end-of-discharge voltage is 60V. For this reason, the dischargers 2a-2f step down the supply voltage to the load 4 to, for example, 50V. However, this output voltage is finely adjusted by a control method for suppressing discharge current variation, which is a feature of the present invention. The dischargers 2a to 2f receive an input when the input voltage reaches the first voltage V1 (60V which is the discharge end voltage of the assembled battery 1) in order to prevent the assembled batteries 1a to 1f from being overdischarged. It has a function of shutting off and stopping discharge, and a function of stopping output when the output power exceeds the output capacity.

  In this DC power supply system, when the AC power supply 6 is effective, the power output from the rectifier 5 is supplied to the load 4, and when the AC power supply 6 is out of power, the power output from the assembled batteries 1a to 1f is discharged to the discharger 2a. Is supplied to the load 4 through 2f.

  In the present embodiment, as in the first embodiment, the control methods A1, A2, and B1 can be applied, and thereby control for suppressing the discharge current concentration can be performed. That is, for example, the control method B1 may be executed according to the flowchart shown in FIG.

  By performing such discharge control in each system, regardless of the number of systems, in the system in which the discharge current is concentrated, the output voltage of the discharger 2 of the system is reduced at the next discharge, so that the discharge current is shared. Becomes smaller and current variation is suppressed. Furthermore, since this discharge control is autonomously performed by the dischargers 2a to 2f of each system, it is not necessary to provide a separate control unit.

  In the first and second embodiments, in the control method B1, the control is performed to lower the discharger output voltage when the output terminal voltage of the discharger 2 after the discharge is stopped is longer than the constant value V2 for a predetermined time T1 or longer (control method). B1) has been described, but in the present embodiment, conversely, control for increasing the discharger output voltage when the time during which the output terminal voltage of the discharger 2 after the discharge stop is equal to or greater than a certain value V2 is short (control report B2 and Explain).

(Control method B2)
The power supply system configuration is the same as that of the second embodiment, and the time when the assembled battery 1 of the own system reaches the first voltage V1 (for example, 60 V which is the discharge end voltage of the assembled battery 1) or the output power exceeds the output capacity The output voltage setting method after the input is cut off is different. The system configuration is the same as in FIG.

  In systems where the discharge current is less than other systems due to variations in the discharge current, the discharge continues until the entire system finishes discharging. The voltage on the output side of the discharger 2 of the system having a small current becomes no voltage. That is, immediately after the discharge is stopped, the discharger 2 whose output side voltage has become non-voltage means that the burden is less than other systems, and this information is used to increase the output voltage at the next discharge.

The discharger 2 receives an input when the assembled battery 1 belonging to the same system reaches V1 (for example, 60V which is the discharge end voltage of the assembled battery 1) or when the output power exceeds the output capacity and the output of the system 1 is stopped. Shut off and stop output. Further, the output side voltage (output end voltage) is monitored thereafter. Here, the voltage of the output side when the second voltage V2 (e.g. 48V) or measures a time T _ON which it persists.

  Finally, the discharge of all other systems is also stopped, and the voltage on the output side becomes less than V2, so the measurement of the duration is stopped at this time.

Up to this point, the control method is the same as the control method B1 of the second embodiment. However, in the control method B2, the discharge device 2 is set to stop discharging (the output side voltage is less than V2) after all the systems stop discharging. measurement results of the time _{T ON} until is when it is less than the second time T2 (e.g. 10 seconds) the output voltage set value increase [Delta] V (e.g., 0.1 V).

The above control of the discharger 2 can be represented by, for example, the flowchart shown in FIG. 5 (in the figure, the second voltage V2 and the second time T2 are represented by V ₂ and T ₂ , respectively). ).

In FIG. 5, the assembled battery of its own system (for example, 1a) reaches a predetermined first voltage V1 (for example, 60V that is the discharge end voltage of the assembled battery 1), or the output power exceeds the output capacity and the system 1 If the output terminal voltage (V _out ) of the discharger 2 is equal to or higher than the second voltage (V ₂ ) in step 31, the process proceeds to step 32. If not, go to step 34. In step 32, time Δt (here, 1 second) is added to the time (T _ON ) in which the output terminal voltage (V _out ) of the discharger 2 is equal to or higher than the second voltage (V ₂ ), and the process proceeds to step 33. Note that _TON is reset to zero at the starting point. In step 33, the process waits for time Δt and returns to step 31. In step 34, when T _ON is less than the second time (T ₂ ), the process proceeds to step 35. Otherwise, the control is terminated. In step 35, the output voltage set value of the own system is autonomously increased by ΔV (for example, 0.1V) and the control is terminated.

  By performing such discharge control in each system, the output voltage of the discharger 2 is increased in the next discharge in a system in which the discharge current is smaller than in other systems, so that the sharing of the discharge current increases and current variation is suppressed. The Furthermore, since this discharge control is autonomously performed by the dischargers 2 of each system, it is not necessary to provide a separate control unit.

  In this embodiment, the output voltage of the discharger 2 is raised or lowered. That is, the control methods B1 and B2 are used in combination.

  The configuration is shown in FIG. 4 as in the second embodiment. When the assembled battery 1 of the own system reaches V1 (for example, 60V which is the discharge end voltage of the assembled battery 1) or the output power exceeds the output capacity, the input is performed. The output voltage setting method after shutting down and stopping output is different.

  In the system where the discharge current is concentrated, the next output voltage set value is increased according to the same control as in the first embodiment, and in the system where the discharge current is small, the next output voltage set value is decreased according to the same control as in the third embodiment. I will let you.

  The discharger 2 cuts off the input when the assembled battery 1 of its own system reaches the first voltage V1 (for example, 60V which is the discharge end voltage of the assembled battery 1) or the output power exceeds the output capacity, and outputs To stop. Thereafter, the voltage on the output side is monitored. Here, when the voltage on the output side is equal to or higher than the second voltage V2 (48V), the time during which it is maintained is recorded. Finally, the discharge of all other systems is also stopped, and the voltage on the output side becomes less than V2, so the measurement of the duration is stopped at this time.

  When the discharger 2 has a measurement result of 10 minutes (first time) or more after its own system stops discharging until all systems stop discharging (the output side voltage is less than V2). When the output voltage set value is lowered by 0.1 V, and it is less than 10 seconds (second time), the output voltage set value is raised by 0.1 V.

The above control of the discharger 2 can be expressed by, for example, the flowchart shown in FIG. 6 (in the figure, the second voltage V2, the first time T1, and the second time T2 are V ₂ , T ₂ , respectively). ₁ and T ₂ ).

In FIG. 6, the assembled battery of its own system (for example, 1a) reaches a predetermined first voltage V1 (for example, 60V which is the discharge end voltage of the assembled battery 1) or the output power exceeds the output capacity and the output is When the stop time (discharge stop time) is described as the starting point, in step 41, when the output terminal voltage (V _out ) of the discharger 2 is equal to or higher than the second voltage (V ₂ ), the process proceeds to step 42; If so, go to Step 44. In step 42, the time ΔT (here, 1 second) is added to the time (T _ON ) in which the output terminal voltage (V _out ) of the discharger 2 is equal to or higher than the second voltage (V ₂ ), and the process proceeds to step 43. Note that _TON is reset to zero at the starting point. In step 43, the process waits for time Δt and returns to step 41. In Step 44, when T _ON is _equal to or longer than the first time (T ₁ ), the process proceeds to Step 46, and otherwise, the process proceeds to Step 45. In step 45, when _TON is less than the second time (T ₂ ), the process proceeds to step 47, and otherwise, the control is terminated. In step 46, the output voltage set value of the own system is autonomously lowered by ΔV (0.1 V) and the control is terminated. In step 47, the output voltage set value of the own system is autonomously increased by ΔV (0.1V), and the control is terminated.

  Since each system autonomously performs such discharge control, in the system in which the discharge current is concentrated, the output voltage of the discharger 2 is reduced in the next discharge, so that the burden of the discharge current is lightened. In the system where there are few, since the output voltage of the discharger 2 increases in the next discharge, the burden of the discharge current increases, and current variation is suppressed. Furthermore, since this discharge control is performed independently by each system of the discharger 2, it is not necessary to provide a separate control unit.

  As described above, the embodiment of the present invention has been described by taking the DC power supply system using the nickel-metal hydride storage battery as an example, but the present invention is not limited to this. Instead of the nickel metal hydride storage battery, another secondary battery such as a lead battery or a lithium ion storage battery may be used. Furthermore, not only the secondary battery but also a DC power source such as a primary battery, an electric double layer capacitor, or a fuel cell can be used, and the discharge current variation can be eliminated. When a primary battery or a fuel cell is used as the direct current power source, a charger is not necessary.

  In each of the above embodiments, the first voltage V1 may be a preset voltage other than the discharge end voltage of the assembled battery, and the voltage V2 is the same. In addition, the first time T1, the second time T2, and the time Δt are set to predetermined values in advance and stored in a memory inside the discharger of each system.

In the above embodiment, the output voltage of the discharger is automatically set. However, this may be manually performed. For example, discharger only stores the above T _ON, without the configuration changes its output voltage, taking into account after power failure of the AC power source to the worker, the value of T _ON stored in discharger Then, the output voltage at the next discharge may be set manually.

In this case, each discharge vessel, made to correspond to T _ON, each stored, the output voltage set value of each of the discharger, the discharge corresponding to T _ON or more T _ON corresponding to dissipating Electric Set the output voltage so that it is equal to or higher than the output voltage setting value of the electric appliance.

Furthermore, for _example, calculates the average value _{T AV} between discharger _{T ON,} the output voltage set value of the discharge vessel which stores a longer _{T ON} than _{T AV,} depending on the size of the T ON _{-T AV} lower Te, an output voltage set value of the discharge vessel which stores the short T _oN than T _AV, etc. bring according to the size of the T _AV -T _oN, this method, although requiring manpower, automatic control Finer control than the case can be performed.

  Below, the effect produced by this invention is demonstrated.

  (1) In a DC power supply system in which a plurality of systems of dischargers are connected in parallel at the output, capacity variations occur between parallel systems due to differences in the arrangement of the dischargers and the state of the battery that is the input of the discharger, which is significant for a specific system. There is a problem that the load is shared, the discharge current between the systems is biased, the discharge of the system ends with the remaining energy that can be discharged, and it is necessary to install extra batteries, which increases cost and space is there.

  According to the present invention, capacity variation is eliminated, and the dischargeable energy stored in the battery is supplied to the load without any excess, so it is possible to reduce the number of extra storage batteries and save cost and space. It becomes.

  (2) There is a method of measuring the discharge current of each system and adjusting the output current of the discharger in order to eliminate the bias of the discharge current, but a separate control device is required, and there is a need for a connection between the control device and each system. Since it is necessary to lay a communication line, another problem such as an increase in cost and a decrease in reliability occurs.

  According to the present invention, if the discharger independently determines and autonomously controls the output voltage, a separate control device is not required, cost can be saved, and a highly reliable DC power supply system can be provided. .

  1: assembled battery, 2: discharger, 3: charger, 4: load, 5: rectifier, 6: AC power supply.

Claims (10)

In a discharger that receives DC power and steps down or boosts the output
Means for measuring the input voltage, means for measuring the output terminal voltage, and means for setting the output voltage value,
A discharger characterized in that the output is stopped when the input voltage decreases during power output and reaches a predetermined first voltage or when the output power exceeds the output capacity. When the output terminal voltage is equal to or higher than a predetermined second voltage at the time when the input voltage decreases during power output and reaches the first voltage or when the output power exceeds the output capacity and the output stops. , Control to lower the output voltage set value,
When the output voltage is less than the second voltage when the input voltage decreases during power output and reaches the first voltage, or when the output stops when the output power exceeds the output capacity, 2. The discharger according to claim 1, wherein at least one of the control for raising the output voltage set value is autonomously performed. In a discharger that receives DC power and steps down or boosts the output
A means for measuring an input voltage, a means for measuring an output terminal voltage, a means for setting an output voltage value, and a time measuring means,
A discharger characterized in that the output is stopped when the input voltage decreases during power output and reaches a predetermined first voltage or when the output power exceeds the output capacity. The time from when the input voltage decreases during power output and reaches the first voltage or when the output power exceeds the output capacity and the output stops until the output terminal voltage becomes less than the predetermined second voltage. measured T _oN, when the measured T _oN is a first time or more predetermined, and controlled to lower the output voltage set value,
4. The control according to claim 3, wherein when the measured _TON is less than a predetermined second time, at least one of the control to increase the output voltage setting value is autonomously performed. Discharger.   5. The discharger according to claim 1, wherein DC power output from the storage battery is input. DC power is input, stepped down or boosted and output, and means for measuring the input voltage and means for measuring the output terminal voltage are provided. A discharge method using a discharger that stops output when voltage is reached or when output power exceeds output capacity,
At the time when the input voltage of the discharger decreases and reaches the first voltage during the power output of the discharger, or when the output power of the discharger exceeds the output capacity and the output of the discharger stops. Control for lowering the output voltage set value of the discharger when the output terminal voltage is equal to or higher than a predetermined second voltage;
At the time when the input voltage of the discharger decreases and reaches the first voltage during the power output of the discharger, or when the output power of the discharger exceeds the output capacity and the output of the discharger stops. When the output terminal voltage is less than the second voltage, at least one of control for increasing the output voltage set value of the discharger is performed. DC power is input, stepped down or boosted and output to measure the input voltage, output terminal voltage measuring means, and time measuring means, and the input voltage is reduced during power output. A discharge method using a discharger that stops output when a predetermined first voltage is reached or when output power exceeds an output capacity,
From the time when the input voltage of the discharger decreases and reaches the first voltage during the power output of the discharger, or when the output power of the discharger exceeds the output capacity and the discharger stops the output. A control for lowering the output voltage set value when the time T _ON until the output terminal voltage becomes less than the predetermined second voltage is measured and the measured T _ON is equal to or longer than the predetermined first time;
When the measured _TON is less than a predetermined second time, at least one of control for increasing an output voltage set value is performed. DC power is input, stepped down or boosted and output to measure the input voltage, output terminal voltage measuring means, and time measuring means, and the input voltage is reduced during power output. A discharge method in which a plurality of dischargers that stop output at the time when a predetermined first voltage is reached or when the output power exceeds the output capacity are connected in parallel,
For each of the dischargers, during the power output of the discharger, the input voltage of the discharger decreases to reach the first voltage or the output power of the discharger exceeds the output capacity and the discharger outputs the measures the time T _oN from the time of stop until the output voltage is less than a predetermined second voltage in correspondence with the dissipating collector,
Wherein the output voltage set value of each of the discharger, such that said discharger output voltage set value or more corresponding to T _ON or more T _ON corresponding to dissipating collector, to carry out setting of the output voltage Discharge method.   The discharge method according to claim 6, 7 or 8, wherein the discharger receives DC power output from the storage battery as an input. There are provided a plurality of assembled batteries in which one or more storage batteries are connected in series, and a discharger is connected to the output of each of the assembled batteries, and the plurality of dischargers are connected in parallel at the output to supply power to the load. In the DC power supply system to supply
A DC power supply system, wherein the discharger is the discharger according to any one of claims 1 to 5.

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