Power supply stabilization device, power supply stabilization method, program and storage medium

Abstract

To provide a power supply stabilization device using a secondary battery.SOLUTION: A power supply stabilization device connected between AC power and an electrical apparatus has a first converter whose AC side is connected to the AC power and converting AC into DC, a second converter whose AC side is connected to the electrical apparatus and converting DC into AC, an output measurement part measuring output voltage of the second converter, a terminal part capable of attaching / detaching a secondary battery, a switching device connected to a DC link connecting a DC side of the first converter and the DC side of the second converter, and switching whether or not power stored in the secondary battery attached to the terminal part is supplied to the DC link, a charging amount measurement part measuring a charging amount of the secondary battery attached to the terminal part, and a control part controlling the switching device based on a measurement result by the output measurement part and the charging amount measurement part.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a power supply stabilizer device.

Background Art

[0002] Depending on the electrical equipment, there are devices with large output fluctuations and large changes in rated voltage depending on the usage method. For example, a welding machine. Using a power source with a small or unstable output for such devices will lead to deterioration of the product quality of the device due to a decrease in output. As a method of solving this problem, it is conceivable to use a socket near the primary power source or to increase the output of the power source. However, when it is necessary to use a socket near the primary power source, the area where the device can be used is limited. Also, increasing the output of the power source may require a lot of costs.

[0003] Also, there is a charger connected to an AC power source that supplies the higher output between the output of the AC power source and the output of a built-in secondary battery (Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the charger described in Patent Document 1 is for DC and does not support devices that use AC. Also, the above charger does not consider coping with fluctuations in the rated voltage. The present invention has been made in consideration of such circumstances, and one of the objects is to provide a stabilized power supply device using a secondary battery.

Means for Solving the Problems

[0006] The power stabilization device according to this invention employs the following configuration. (1) A power stabilization device according to one aspect of the present invention comprises: a first converter connected between an AC power source and an electrical device, the AC side of which is connected to the AC power source and converts AC to DC; a second converter, the AC side of which is connected to the electrical device and converts DC to AC; an output measuring unit for measuring the output voltage of the second converter; a terminal section to which a secondary battery can be attached and detached; a switching device connected to a DC link connecting the DC side of the first converter and the DC side of the second converter, for switching whether or not to supply power stored in the secondary battery attached to the terminal section to the DC link; a charge amount measuring unit for measuring the charge amount of the secondary battery attached to the terminal section; and a control unit for controlling the switching device based on the measurement results from the output measuring unit and the charge amount measuring unit.

[0007] (2) In the embodiment of (1) above, the device comprises a secondary battery attached to the terminal portion.

[0008] (3) In the embodiment of (1) or (2) above, the switching device is a DC / DC converter in which one terminal is connected to the terminal portion, and when supplying power stored in the secondary battery to the DC link, the output voltage of the other terminal is made higher than the voltage of the DC link.

[0009] (4) In any embodiment of (1) to (3) above, the second converter is provided with a switch that can change the set voltage of the output, and the control unit controls the switching device based on the set voltage.

[0010] (5) In any of the embodiments of (1) to (4) above, when the AC power supplied to the electrical equipment, as measured by the output measuring unit, increases and approaches a predetermined power, and the charge amount of the secondary battery, as measured by the charge amount measuring unit, is equal to or greater than a predetermined amount, the control unit controls the switching device so that power is supplied from the secondary battery to the second converter.

[0011] (6) In any embodiment of (1) to (5) above, the first converter supplies a DC current to the secondary battery, and the switching device adjusts the power supplied from the first converter to the secondary battery.

[0012] (7) In any of the embodiments described in (1) to (6) above, when the charge amount measuring unit is unable to measure the charge amount of the secondary battery, the control unit controls the switching device so that power is not supplied from the terminal to the second converter and from the first converter to the terminal.

[0013] (8) In any embodiment of (1) to (7) above, the output measuring unit detects whether the electrical equipment and the second converter are connected, and if the output measuring unit detects that the electrical equipment and the second converter are not connected, the control unit controls the switching device so that power is supplied from the first converter to the secondary battery. [Effects of the Invention]

[0014] According to embodiments (1) to (5), the increase in the voltage of the AC power supply can be suppressed by supplying power from the secondary battery based on the output voltage value and the charge level of the secondary battery. According to embodiments (6) and (8), the secondary battery can be charged by supplying power to the secondary battery from an AC power source based on the output voltage value and the charge level of the secondary battery. According to the embodiment of (7), when power cannot be supplied from the secondary battery, it is possible to supply power that is substantially the same as that supplied when connected to a normal AC power source. [Brief explanation of the drawing]

[0015] [Figure 1] This figure shows the configuration of the power stabilization device 1 according to the first embodiment. [Figure 2] This is a flowchart showing the operation of the control unit 22 according to the first embodiment. [Figure 3] This is an example of a timing chart for controlling the switching device 20. [Figure 4] It is a diagram showing the configuration of the power supply stabilization device 1 according to the second embodiment.

Embodiments for Carrying Out the Invention

[0016] Hereinafter, embodiments of the power supply stabilization device of the present invention will be described with reference to the drawings.

[0017] [Overall Configuration] <First Embodiment> FIG. 1 is a diagram showing the configuration of the power supply stabilization device 1 according to the first embodiment. The power supply stabilization device 1 includes a first converter 10, a DC link 11, a second converter 12, an output measurement unit 14, a DC link voltage measurement unit 15, a charge measurement unit 16, a terminal unit 18, a secondary battery 19, a switching device 20, and a control unit 22. The power supply stabilization device 1 has input terminals and output terminals. The input terminals are connected to the AC power supply 100. The output terminals are connected to the electrical equipment 200.

[0018] The first converter 10 converts the AC power supplied from the AC power supply 100 via the input terminals into DC power and supplies it to the DC link 11. The first converter 10 is, for example, an AC / DC converter. The DC link 11 connects the first converter 10, the second converter 12, and the switching device 20.

[0019] The second converter 12 converts the DC power supplied from the first converter 10 or the switching device 20 via the DC link 11 into AC power and supplies it to the electrical equipment 200 via the output terminals. The second converter 12 is, for example, a DC / AC inverter. The voltage of the power supplied by the second converter 12 to the electrical equipment 200 (hereinafter, the set voltage) is not limited to the same voltage as the voltage of the power supplied by the AC power supply 100. For example, when the AC power supply 100 supplies power with a voltage of 100V, the power supply stabilization device 1 may supply power with a voltage of 200V to the electrical equipment 200. Also, the set voltage may change according to an external input. For example, the power supply stabilization device 1 has a switch for setting the set voltage to 100V or 200V, and the set voltage changes by switching the switch.

[0020] The output measurement unit 14 measures the AC power supplied to the electrical device 200. The output measurement unit 14 is provided, for example, between the second converter 12 and the electrical device 200. The output measurement unit 14 includes, for example, a current sensor and a calculation unit. The calculation unit calculates the output power by multiplying the magnitude of the current measured by the current sensor by the set voltage of the second converter 12. The output measurement unit 14 uses the result of the calculation by the calculation unit as the output power.

[0021] The DC link voltage measurement unit 15 measures the voltage of the DC link 11 with respect to the ground.

[0022] The charge measurement unit 16 measures the charge amount of the secondary battery 19 attached to the terminal unit 18. The secondary battery 19 is detachable from the terminal unit 18 and can be repeatedly used by charging.

[0023] The switching device 20 is provided between the terminal unit 18 and the second converter 12. The switching device 20 is, for example, a buck-boost DC / DC converter. The switching device 20 includes a first terminal 31 and a second terminal 32. The first terminal 31 is connected to the terminal unit 18, and the second terminal 32 is connected to the DC link 11. The switching device 20 adjusts the voltage output from the first terminal 31. For example, the switching device 20 makes the voltage output to the second terminal 32 higher than the voltage of the DC link 11 (the output voltage of the first converter 10) so that power is supplied from the secondary battery 19 to the DC link 11. Also, for example, the switching device 20 makes the voltage output to the second terminal 32 lower than the voltage of the DC link 11 (the output voltage of the first converter 10) so that power is not supplied from the secondary battery 19 to the DC link 11.

[0024] The control unit 22 controls the switching device 20 based on the AC voltage measured by the output measurement unit 14, the charge amount of the secondary battery 19 attached to the terminal unit 18 measured by the charge amount measurement unit 16, and the voltage of the DC link 11 measured by the DC link voltage measurement unit 15. The control unit 22 is implemented, for example, by a hardware processor such as a CPU (Central Processing Unit) executing a program (software). Some or all of these components may be implemented by hardware (including circuitry) such as an LSI (Large Scale Integration), ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array), or GPU (Graphics Processing Unit), or by the cooperation of software and hardware. The program may be stored in advance in a storage device such as an HDD (Hard Disk Drive) or flash memory (a storage device with a non-transient storage medium), or it may be stored in a removable storage medium such as a DVD or CD-ROM (a non-transient storage medium) and installed when the storage medium is installed in a drive device.

[0025] For example, when the charge level of the secondary battery 19 attached to the terminal section 18 exceeds a predetermined amount, and the power value measured by the output measurement section 14 increases and approaches the power threshold, the control unit 22 controls the switching device 20 so that power is supplied from the secondary battery 19 to the second converter 12. The power threshold is, for example, the rated power of the AC power supply 100. Here, the power supplied from the secondary battery 19 to the second converter 12 changes depending on the voltage of the DC link 11.

[0026] Figure 2 is a flowchart showing the operation of the control unit 22 according to the first embodiment. First, the control unit 22 determines whether the power value measured by the output measurement unit 14 is greater than the switching threshold (step S102). The switching threshold is a value less than the power threshold by a predetermined value (P1). For example, P1 is power equivalent to 1% of the rated power. In other words, in this embodiment, by determining whether the power value measured by the output measurement unit 14 is greater than the switching threshold, it is determined whether the power value has increased and is approaching the power threshold. If the output power is greater than the switching threshold, the control unit 22 determines whether the charge amount of the secondary battery 19 measured by the charge amount measurement unit 16 is greater than a predetermined amount (step S104). If the charge amount of the secondary battery 19 is greater than a predetermined amount, the control unit 22 controls the switching device 20 so that the power of the secondary battery 19 is supplied to the second converter 12 (step S106).

[0027] The control unit 22 may control the switching device 20 when the power value measured by the output measurement unit 14 is below a switching threshold, or when the charge amount of the secondary battery 19 measured by the charge amount measurement unit 16 is below a predetermined amount, so that the power of the secondary battery 19 is not supplied to the second converter 12.

[0028] Figure 3 is an example of a timing chart when the control unit 22 controls the switching device 20. When the electrical device 200 is put into use, the AC power supplied to the electrical device 200 increases. The control unit 22 keeps the switching device 20 OFF until time T1 because the output power is less than the switching threshold (a value less than a predetermined value (P1) than the power threshold). When the output power reaches the switching threshold at time T1, the control unit 22 controls the switching device 20 to mitigate the increase in output power. As a result, the switching device 20 switches from OFF to ON and starts operating. The switching device 20 supplies power to the second converter 12 from the secondary battery 19 attached to the terminal section 18, so that the output power is kept constant after a certain period of time after the switching device 20 is turned ON, preventing it from exceeding the power threshold. Since power is supplied from the secondary battery 19 after time T1, the charge level of the secondary battery 19 decreases. Also, since power is supplied from the secondary battery 19 after time T1, the output of the AC power supply 100 does not change or decreases.

[0029] As a result, when the power supplied to the electrical equipment 200 increases and approaches the power threshold, the increase in power supplied from the AC power supply 100 to the first converter 10 is suppressed, preventing the power supplied from the AC power supply 100 from exceeding the rated power.

[0030] <Second Embodiment> Figure 4 shows the configuration of the power stabilization device 1 according to the second embodiment. The control unit 22 according to the second embodiment controls the switching device 20 based on the power value measured by the output measurement unit 14 and the charge amount of the secondary battery 19 attached to the terminal unit 18, as measured by the charge amount measurement unit 16, in addition to the control unit 22 according to the first embodiment. For example, when the charge amount of the secondary battery 19 attached to the terminal unit 18 is less than or equal to a predetermined amount and the power value measured by the output measurement unit 14 is less than a predetermined value, the control unit 22 controls the switching device 20 so that power is supplied from the first converter 10 to the terminal unit 18.

[0031] In the second embodiment, the power consumed by the electrical equipment 200 is less than the power that the AC power supply 100 can supply. The switching device 20 lowers the voltage output from the second terminal 32 to a voltage lower than the voltage of the DC link 11, thereby supplying power from the first converter 10 to the terminal section 18.

[0032] This allows power to be supplied to the terminal section 18 and the secondary battery 19 to be charged when the output to the electrical device 200 is low and the charge level of the secondary battery 19 is low. Therefore, there is no need to remove the secondary battery 19 and charge it separately.

[0033] <Other Embodiments> The output measurement unit 14 calculates the power value from the current value, but is not limited to this. For example, the output measurement unit 14 may measure the current value, and the control unit 22 may control the switching device 20 based on the measured current value. The output measurement unit 14 may also measure both the current value and the voltage value and calculate the power.

[0034] When the charge level measuring unit 16 cannot measure the charge level of the secondary battery 19 attached to the terminal unit 18, the control unit 22 may control the switching device 20 so that power is not supplied from the terminal unit 18 to the second converter 12 and from the first converter 10 to the terminal unit 18. The charge level measuring unit 16 cannot measure the charge level of the secondary battery 19 attached to the terminal unit 18 when, for example, the secondary battery 19 has been removed from the terminal unit 18 or the secondary battery 19 attached to the terminal unit 18 is faulty. Through the control of the switching device 20 by the control unit 22, the power supplied from the AC power supply 100 is converted by the first converter 10, converted by the second converter 12, and supplied to the electrical equipment 200. In other words, substantially the same power as the power supplied from the AC power supply 100 is supplied to the electrical equipment 200.

[0035] The power stabilization device 1 may have a function to determine whether or not the secondary battery 19 is attached to the terminal section 18. When it is determined that the secondary battery 19 has been removed from the terminal section 18, the control unit 22 controls the switching device 20 so that the power supplied from the AC power supply 100 is converted by the first converter 10, converted by the second converter 12, and supplied to the electrical equipment 200.

[0036] When the output measurement unit 14 cannot measure the power supplied to the electrical equipment 200, the control unit 22 may control the switching device 20 so that power is supplied from the first converter 10 to the terminal unit 18. The output measurement unit 14 cannot measure the power supplied to the electrical equipment 200 when, for example, the electrical equipment 200 is not connected to the second converter 12. Through the control of the switching device 20 by the control unit 22, the power supplied from the AC power source is converted by the first converter 10, converted again by the switching device 20, and supplied to the terminal unit 18. As a result, the secondary battery 19 attached to the terminal unit 18 is charged by the power supplied by the AC power source 100.

[0037] Furthermore, the power stabilization device 1 may have a function to determine whether or not the electrical equipment 200 is connected to the power stabilization device 1. When it is determined that the electrical equipment 200 is not connected to the power stabilization device 1, the control unit 22 controls the switching device 20 so that power is supplied from the first converter 10 to the secondary battery 19.

[0038] Although embodiments for carrying out the present invention have been described above using examples, the present invention is not limited in any way to these embodiments, and various modifications and substitutions can be made without departing from the spirit of the present invention. [Explanation of Symbols]

[0039] 1 Power stabilizer 10 First Converter 11 DC Link 12. Second Converter 14 Output measurement section 16 Charge amount measuring section 18 Terminal section 19 Secondary battery 20 Switching device 22 Control Unit 31 1st terminal 32 2nd terminal 100 AC power supply 200 Electrical equipment

Claims

1. A power supply stabilization device connected between an AC power supply and an electrical device, a first converter whose AC side is connected to the AC power supply and converts AC into DC; a second converter whose AC side is connected to the electrical device and converts DC to AC; an output measuring unit that measures an output voltage of the second converter; a terminal portion to which a secondary battery can be attached and detached; a switching device connected to a DC link connecting a DC side of the first converter and a DC side of the second converter, and configured to switch whether or not power stored in a secondary battery attached to the terminal portion is to be supplied to the DC link; a charge amount measuring unit that measures the charge amount of the secondary battery attached to the terminal unit; a control unit that controls the switching device based on the measurement results of the output measurement unit and the charge amount measurement unit; A power supply stabilizer comprising:

2. a secondary battery attached to the terminal portion; The power supply stabilizer according to claim 1 , comprising:

3. the switching device is a DC / DC converter having a first terminal connected to the terminal unit and a second terminal connected to the DC link, and when power stored in the secondary battery is supplied to the DC link, the switching device makes the output voltage of the second terminal higher than the voltage of the DC link; 3. The power supply stabilizer according to claim 1 or 2.

4. a switch capable of changing a set voltage output by the second converter; The control unit controls the switching device based on the set voltage. The power supply stabilizer according to any one of claims 1 to 3.

5. the AC power supplied to the electrical device measured by the output measuring unit increases and approaches a predetermined power, When the charge amount of the secondary battery measured by the charge amount measurement unit is equal to or greater than a predetermined amount, the control unit controls the switching device so that power is supplied from the secondary battery to the second converter. The power supply stabilizer according to claim 1 .

6. the value of the AC power supplied to the electrical device measured by the output measuring unit is smaller than a predetermined power, When the charge amount of the secondary battery measured by the charge amount measurement unit is equal to or less than a predetermined amount, the control unit controls the switching device so that power is supplied from the DC link to the secondary battery. The power supply stabilizer according to claim 1 .

7. When the charge amount measurement unit cannot measure the charge amount of the secondary battery, the control unit controls the switching device so that power is not supplied from the terminal unit to the second converter and from the first converter to the terminal unit. The power supply stabilizer according to claim 1 .

8. the output measuring unit detects whether the electrical device and the second converter are connected; When the output measurement unit detects that the electrical device and the second converter are not connected, the control unit controls the switching device so that power is supplied from the first converter to the secondary battery. The power supply stabilizer according to any one of claims 1 to 7.

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