Power supply device

Abstract

To reduce a capacity of a transformer.SOLUTION: A neutral node N3 is connected to a neutral line L20 of a power distribution facility 20. A first output node N4 is connected to a first power supply line L21 of the power distribution facility 20. A second output node N5 is connected to a second power supply line L22 of the power distribution facility 20. A transformer 16 has: a primary winding 16a connected between the first input node N1 and the second input node N2; and a secondary winding 16b connected between the neutral node N3 and the first output node N4, and is configured such that an output AC voltage between the neutral node N3 and the first output node N4 is in antiphase with respect to an input AC voltage between the first input node N1 and the second input node N2. A first connection line L1 connects the first input node N1 and the neutral node N3. A second connection line L2 connects the second input node N2 and the second output node N5.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a power supply device for checking electrical circuits. This power supply device includes an input plug that can be connected to a single-phase, two-wire temporary power outlet for construction work, a single-phase compound transformer with a single-phase, two-wire primary side and a single-phase, three-wire secondary side, a single-phase, three-wire output connector connected to the secondary side of the transformer, and breakers located before and after the transformer. This power supply device is used, for example, to check the electrical wiring in each dwelling unit in an apartment building or to check the performance of fans and other devices. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 4-87481 Summary of the Invention [Problem to be solved by the invention]

[0004] In the power supply device of Patent Document 1, it is preferable to reduce the capacity of the transformer for the purpose of weight reduction, etc. However, the configuration of Patent Document 1 uses a single-phase compound transformer with a single-phase two-wire system on the primary side and a single-phase three-wire system on the secondary side, making it difficult to reduce the capacity of the transformer.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a power supply device that can reduce the capacity of a transformer. [Means for solving the problem]

[0006] The present invention relates to a power supply device connected to a power distribution facility having a neutral conductor, a first power supply conductor, and a second power supply conductor. The power supply device includes a transformer having a first input node and a second input node to which an input AC voltage is supplied, a neutral node connected to the neutral conductor, a first output node connected to the first power supply conductor, a second output node connected to the second power supply conductor, a primary winding connected between the first input node and the second input node, and a secondary winding connected between the neutral node and the first output node, such that an output AC voltage applied between the neutral node and the first output node is in opposite phase to an input AC voltage applied between the first input node and the second input node, a first connecting wire connecting one end of the primary winding to one end of the secondary winding, and a second connecting wire connecting the other end of the primary winding to the second output node. [Effects of the Invention]

[0007] According to the present invention, both the primary side and the secondary side of the transformer can be single-phase two-wire, so the capacity of the transformer can be reduced compared to when a transformer whose primary side is single-phase two-wire and whose secondary side is single-phase three-wire is used. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a circuit block diagram illustrating a configuration of a power supply device according to an embodiment; [Figure 2] FIG. 10 is a circuit block diagram illustrating the configuration of a power supply device according to a modified example of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, the embodiments will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals and their description will not be repeated.

[0010] (power supply) 1 illustrates the configuration of a power supply device 10 according to an embodiment. The power supply device 10 is connected to a power distribution facility 20. The power distribution facility 20 has a neutral line L20, a first power line L21, and a second power line L22. For example, the power distribution facility 20 is a single-phase three-wire distribution board installed indoors (e.g., in a dwelling).

[0011] In this example, it is assumed that an AC voltage of "100V" is applied between the neutral conductor L20 and the first power conductor L21. Similarly, it is assumed that an AC voltage of "100V" is applied between the neutral conductor L20 and the second power conductor L22. It is also assumed that an AC voltage of "200V" is applied between the first power conductor L21 and the second power conductor. Note that an AC voltage of "100V (or 200V)" refers to an AC voltage with an amplitude of "100V (or 200V)."

[0012] For example, when the neutral wire L20, the first power supply wire L21, and the second power supply wire L22 are connected to an AC power source such as a pole-mounted transformer via a service line (not shown), an AC voltage of "100V" is applied between the neutral wire L20 and the first power supply wire L21, an AC voltage of "100V" is applied between the neutral wire L20 and the second power supply wire L22, and an AC voltage of "200V" is applied between the first power supply wire L21 and the second power supply wire L22.

[0013] In this example, the power supply device 10 is configured to be able to output an AC voltage of 100 V and an AC voltage of 200 V. These AC voltages are examples of multiple types of output AC voltages, each having a different amplitude. Specifically, the power supply device 10 is configured to apply an AC voltage of "100 V" between the neutral conductor L20 and the first power supply line L21 of the power distribution equipment 20, apply an AC voltage of "100 V" between the neutral conductor L20 and the second power supply line L22 of the power distribution equipment 20, and apply an AC voltage of "200 V" between the first power supply line L21 and the second power supply line L22 of the power distribution equipment 20.

[0014] In this way, the power supply device 10 is connected to the neutral wire L20, the first power supply wire L21, and the second power supply wire L22 of the power distribution equipment 20, and AC voltage is supplied from the power supply device 10 to the neutral wire L20, the first power supply wire L21, and the second power supply wire L22, thereby making it possible to test the power distribution equipment 20 and / or the load connected to the power distribution equipment 20.

[0015] The loads connected to the power distribution equipment 20 include loads driven by 100V AC voltage and loads driven by 200V AC voltage. Examples of loads include lighting fixtures, kitchen appliances, ventilation fans, and air conditioners. Examples of tests include a lighting test to check whether lighting fixtures are on, and a polarity test to check the polarity of an outlet. For example, the test disclosed in Japanese Patent No. 5883363 may be performed.

[0016] [Configuration of power supply device] The power supply device 10 includes a battery 11, a conversion unit 12, a power supply circuit 13, a memory unit 14, a control unit 15, a neutral connection line L10, a first power supply connection line L11, and a second power supply connection line L12. The battery 11, conversion unit 12, power supply circuit 13, memory unit 14, and control unit 15 are housed in a casing (not shown) of the power supply device 10. The neutral connection line L10, the first power supply connection line L11, and the second power supply connection line L12 are drawn out from the casing of the power supply device 10. The power supply device 10 constitutes a portable power source that can be carried around.

[0017] 〔battery〕 The battery 11 stores power. The battery 11 also supplies a DC voltage. In this example, the battery 11 is a rechargeable storage battery, and the power supply device 10 includes a charging mechanism (not shown) for charging the battery 11. Examples of the storage battery include a lead-acid battery and a lithium-ion battery.

[0018] [Conversion section] The conversion unit 12 converts the DC voltage supplied from the battery 11 into an input AC voltage. In this example, the conversion unit 12 has a pair of input terminals connected to the battery 11, a pair of output terminals connected to the power supply circuit 13, and a plurality of switching elements. The conversion unit 12 converts the DC voltage supplied to the pair of input terminals into an AC voltage by turning on and off (switching operation) the plurality of switching elements, and outputs the AC voltage from the pair of output terminals as an input AC voltage. For example, the conversion unit 12 is an inverter.

[0019] [Power circuit] The power supply circuit 13 includes a first input node N1, a second input node N2, a neutral node N3, a first output node N4, a second output node N5, a transformer 16, a first connecting line L1, a second connecting line L2, and a switch 17.

[0020] <First input node and second input node> An input AC voltage is supplied to the first input node N1 and the second input node N2. In this example, the first input node N1 and the second input node N2 are connected to the first output terminal and the second output terminal of the conversion unit 12, respectively, and the input AC voltage generated by the conversion unit 12 is applied between the first input node N1 and the second input node N2.

[0021] Neutral Node The neutral node N3 is connected to the neutral line L20. In this example, the neutral node N3 is connected to one end of the neutral connection line L10. The other end of the neutral connection line L10 is connected to the neutral line L20 of the power distribution facility 20 (for example, an end of the neutral line L20).

[0022] The neutral node N3 is grounded. For example, the neutral node N3 is connected to an external ground electrode (not shown) via a ground wire. Alternatively, the neutral node N3 may be grounded by being connected to the neutral line L20 (grounded neutral line L20) of the power distribution facility 20 via a neutral connection line L10.

[0023] <First output node> The first output node N4 is connected to the first power supply line L21. In this example, the first output node N4 is connected to one end of the first power supply connection line L11. The other end of the first power supply connection line L11 is connected to the first power supply line L21 of the power distribution facility 20 (for example, an end of the first power supply line L21).

[0024] <Second output node> The second output node N5 is connected to the second power supply line L22. In this example, the second output node N5 is connected to one end of the second power supply connecting line L12. The other end of the second power supply connecting line L12 is connected to the second power supply line L22 of the power distribution facility 20 (for example, an end of the second power supply line L22).

[0025] <transformer> The transformer 16 has a primary winding 16a and a secondary winding 16b. The primary winding 16a and the secondary winding 16b are magnetically coupled to each other, and when a voltage is applied to the primary winding 16a and a current flows through the primary winding 16a, a current flows through the secondary winding 16b and a voltage (a voltage corresponding to the voltage applied to the primary winding 16a) is generated in the secondary winding 16b.

[0026] In the following, the dotted end of the winding shown in Fig. 1 (the end with a dot) will be referred to as "one end" of the winding, and the non-dotted end of the winding shown in Fig. 1 (the end without a dot) will be referred to as "the other end" of the winding. In transformer 16, when a current flows from one end to the other end of primary winding 16a, a current flows from one end to the other end of secondary winding 16b in response to that current.

[0027] In the transformer 16, the primary winding 16a is connected between a first input node N1 and a second input node N2, and the secondary winding 16b is connected between a neutral node N3 and a first output node N4. The transformer 16 is configured so that an AC voltage applied between the neutral node N3 and the first output node N4 (hereinafter referred to as an "output AC voltage") is in opposite phase to an input AC voltage applied between the first input node N1 and the second input node N2.

[0028] In this way, both the primary side and the secondary side of the transformer 16 are configured as single-phase two-wire. Note that the input AC voltage is an AC voltage with the potential of the first input node N1 as a reference, and the output AC voltage is an AC voltage with the potential of the neutral node N3 as a reference.

[0029] In this example, the primary winding 16a and the secondary winding 16b are provided to have depolarized polarity. The other end (dot side) of the primary winding 16a is connected to a first input node N1 via a first wiring LN1. One end (non-dot side) of the primary winding 16a is connected to a second input node N2 via a second wiring LN2. One end of the secondary winding 16b is connected to a neutral node N3 via a third wiring LN3. The other end of the secondary winding 16b is connected to a first output node N4 via a fourth wiring LN4.

[0030] In this example, the amplitude of the output AC voltage output from the secondary winding 16b of the transformer 16 and applied between the neutral node N3 and the first output node N4 is equivalent to the amplitude of the input AC voltage applied between the first input node N1 and the second input node N2 and input to the primary winding 16a of the transformer 16. For example, the inductance value of the secondary winding 16b is equivalent to the inductance value of the primary winding 16a. Note that "equivalent" means that the two are substantially the same, and for example, indicates that the difference between them is within a predetermined tolerance (e.g., 5%) of the transformer 16.

[0031] <First connecting line> The first connection line L1 connects the first input node N1 and the neutral node N3. In this example, the first connection line L1 connects "a midpoint of the first wiring LN1 that connects the first input node N1 and the other end of the primary winding 16a" and "a midpoint of the third wiring LN3 that connects one end of the secondary winding 16b and the neutral node N3."

[0032] <Second connecting line> The second connection line L2 connects the second input node N2 and the second output node N5. In this example, the second connection line L2 connects "a midpoint of the second wiring LN2 that connects the second input node N2 and one end of the primary winding 16a" to "the second output node N5."

[0033] <switch> The switch 17 is configured to be switchable between a conductive state and a cut-off state. The conductive state is a state in which the second input node N2 and the first output node N4 are electrically connected. The cut-off state is a state in which the second input node N2 and the first output node N4 are electrically cut off.

[0034] In this example, one end of the switch 17 is connected to a midpoint of the fourth wiring LN4 that connects the other end of the secondary winding 16b and the first output node N4, and the other end of the switch 17 is connected to a midpoint of the second connection line L2 that connects the second input node N2 and the second output node N5.

[0035] <Various sensors> Furthermore, the power supply device 10 (particularly the power supply circuit 13) is provided with various sensors (not shown), such as a current sensor and a voltage sensor. Information obtained by these various sensors is sent to the control unit 15.

[0036] <Storage part> The storage unit 14 stores various types of information and data. For example, the storage unit 14 stores information used to control the power supply device 10 (for example, set values ​​such as thresholds), information obtained by various sensors (for example, measured values), information and data input from outside the power supply device 10, and the like.

[0037] <Control Unit> Control unit 15 is connected to each part of power supply device 10 via signal lines and is configured to be able to transmit signals between each part of power supply device 10. Control unit 15 controls each part of power supply device 10 based on instructions input from outside power supply device 10, information obtained by various sensors provided in power supply device 10, various information and data stored in storage unit 14, etc. For example, control unit 15 has a processor and a memory that stores various programs executed by the processor. Various processes (functions) of control unit 15 are realized by the processor executing the various programs.

[0038] In this example, the control unit 15 controls the conversion unit 12 so that an input AC voltage having a desired voltage is generated. The control unit 15 also controls the switch 17. The control of the switch 17 will be described in detail later.

[0039] The above-mentioned "instructions input from outside the power supply device 10" may be instructions input by operating an operation unit (not shown) provided in the power supply device 10, or instructions received by a communication unit (not shown) provided in the power supply device 10. Examples of the operation unit include a touch panel and operation buttons.

[0040] Furthermore, the memory of the control unit 15 may store part of the information (for example, set values ​​such as thresholds) used to control the power supply device 10. For example, the control unit 15 may include a microcontroller that executes predetermined control (calculation). The information used to control the power supply device 10 may be expressed as values ​​set in a program. Alternatively, the control unit 15 may include a dedicated circuit that executes predetermined control (calculation). The information used to control the power supply device 10 may be expressed as parameter values ​​of a computing element that constitutes the dedicated circuit. The control unit 15 may be realized solely by hardware such as a dedicated circuit, or may be realized by a combination of hardware and software such as a program.

[0041] [Neutral connection wire, first power supply connection wire, and second power supply connection wire] One end of the neutral connection line L10 is connected to the neutral node N3, and the other end of the neutral connection line L10 is configured to be connectable to a neutral line L20 of the power distribution facility 20. For example, the neutral connection line L10 is configured by a cable (an electric wire covered with an insulating member), and the other end of the neutral connection line L10 is configured by a clip such as an alligator clip.

[0042] One end of the first power supply connecting line L11 is connected to the first output node N4, and the other end of the first power supply connecting line L11 is configured to be connectable to the first power supply line L21 of the power distribution facility 20. One end of the second power supply connecting line L12 is connected to the second output node N5, and the other end of the second power supply connecting line L12 is configured to be connectable to the second power supply line L22 of the power distribution facility 20. For example, the configurations of the first power supply connecting line L11 and the second power supply connecting line L12 are similar to the configuration of the neutral connecting line L10.

[0043] [Basic operation of the power supply unit] Next, we will explain the basic operation of the power supply device 10. In this example, when the neutral connection line L10, the first power supply connection line L11, and the second power supply connection line L12 are connected to the neutral line L20, the first power supply line L21, and the second power supply line L22 of the power distribution facility 20, respectively, and the conversion unit 12 is started up to supply an input AC voltage to the input nodes (first input node N1 and second input node N2) of the power supply circuit 13, the following operation occurs.

[0044] In the power supply circuit 13, the transformer 16 outputs an output AC voltage from the secondary winding 16b according to the input AC voltage applied to the primary winding 16a. One end (the dotted side) of the secondary winding 16b is connected to the neutral node N3, and the other end (the non-dotted side) of the secondary winding 16b is connected to the first output node N4. Therefore, the output AC voltage (hereinafter referred to as the "first output AC voltage") applied between the neutral node N3 and the first output node N4 is an AC voltage according to the input AC voltage (an AC voltage of 100 V in this example). The first output AC voltage is an AC voltage based on the potential of the neutral node N3.

[0045] Since the first input node N1 is connected to the neutral node N3 via the first connection line L1, the neutral node N3 has the same potential as the first input node N1. Since the second input node N2 is connected to the second output node N5 via the second connection line L2, the second output node N5 has the same potential as the second input node N2. Therefore, the output AC voltage (hereinafter referred to as the "second output AC voltage") applied between the neutral node N3 and the second output node N5 is the input AC voltage (an AC voltage of 100 V in this example). The second output AC voltage is an AC voltage based on the potential of the neutral node N3.

[0046] The first output AC voltage applied between the neutral node N3 and the first output node N4 is in opposite phase to the input AC voltage applied between the first input node N1 and the second input node N2. The second output AC voltage applied between the neutral node N3 and the second output node N5 is in phase with the input AC voltage applied between the first input node N1 and the second input node N2. Therefore, the output AC voltage applied between the first output node N4 and the second output node N5 (hereinafter referred to as the "third output AC voltage") is an AC voltage (200 V in this example) having an amplitude equivalent to the sum of the amplitudes of the first output AC voltage and the second output AC voltage.

[0047] The neutral node N3, the first output node N4, and the second output node N5 are connected to the neutral conductor L20, the first power supply conductor L21, and the second power supply conductor L22 of the power distribution facility 20 by the neutral connection conductor L10, the first power supply connection conductor L11, and the second power supply connection conductor L12, respectively. As a result, the AC voltage applied between the neutral conductor L20 and the first power supply conductor L21 becomes the "first output AC voltage (100V AC voltage)" applied between the neutral node N3 and the first output node N4. The AC voltage applied between the neutral conductor L20 and the second power supply conductor L22 becomes the "second output AC voltage (100V AC voltage)" applied between the neutral node N3 and the second output node N5. The AC voltage applied between the first power supply line L21 and the second power supply line L22 becomes a "third output AC voltage (AC voltage of 200 V)" applied between the first output node N4 and the second output node N5.

[0048] [Switch control] Next, a description will be given of the control of the switch 17. When the power supply device 10 is operating (when the basic operation of the power supply device 10 is being performed), the control unit 15 performs the following processing.

[0049] The control unit 15 determines whether the output power between the neutral node N3 and the first output node N4 exceeds the capacity of the transformer 16. For example, the control unit 15 derives the output power between the neutral node N3 and the first output node N4 based on the product of the "current value (measured value) of the current flowing through the wiring (fourth wiring LN4) connecting the other end of the secondary winding 16b of the transformer 16 and the first output node N4" and the "amplitude (estimated value) of the AC voltage applied between the neutral node N3 and the first output node N4." Note that the capacity of the transformer 16 refers to the rated capacity of the transformer 16 (the maximum power at which the transformer 16 can be safely used).

[0050] The "current value of the current flowing through the wiring (fourth wiring LN4) connecting the other end of the secondary winding 16b of the transformer 16 and the first output node N4" may be detected by a current sensor provided on the fourth wiring LN4. The "amplitude of the AC voltage applied between the neutral node N3 and the first output node N4" and the "capacitance of the transformer 16" may be information stored in the storage unit 14. The control unit 15 may perform the above processing (deriving and determining the output power) based on the current value detected by the current sensor and the information stored in the storage unit 14.

[0051] When the output power between the neutral node N3 and the first output node N4 exceeds the capacity of the transformer 16, the control unit 15 switches the switch 17 from a cut-off state to a conductive state. As a result, the first output node N4 is connected to the second input node N2 via the conductive switch 17, and the first output node N4 has the same potential as the second input node N2. The neutral node N3 has the same potential as the first input node N1. Therefore, the output capacitance between the neutral node N3 and the first output node N4 changes from "a capacitance that depends on the capacitance of the transformer 16" to "a capacitance that depends on the larger of the capacitance of the transformer 16 and the input capacitance."

[0052] The above "output capacity" refers to the maximum power that can be output from the secondary winding 16b of the transformer 16. The above "input capacity" refers to the maximum power that can be input to the primary winding 16a of the transformer 16.

[0053] Then, when the output power between the neutral node N3 and the first output node N4 no longer exceeds the capacitance of the transformer 16, the control unit 15 switches the switch 17 from the conductive state to the cut-off state, thereby disconnecting the first output node N4 from the second input node N2, and the output capacitance between the neutral node N3 and the first output node N4 returns from "capacity dependent on the larger of the capacitance of the transformer 16 and the input capacitance" to "capacity dependent on the capacitance of the transformer 16."

[0054] When switch 17 is in a conductive state, first output node N4 and second output node N5 have the same potential, and therefore the voltage (potential difference) applied between first output node N4 and second output node N5 is zero. In this case, it becomes impossible to perform tests using "200V AC voltage" among tests on power distribution facility 20 and / or loads connected to power distribution facility 20.

[0055] Therefore, when switch 17 is turned on, control unit 15 may be configured to notify that a test using "200V AC voltage" will no longer be possible. For example, control unit 15 may cause a display unit (not shown) provided in power supply device 10 to display an image notifying the above. Alternatively, control unit 15 may cause an audio output unit (not shown) provided in power supply device 10 to output a sound notifying the above.

[0056] [Comparison between the embodiment and the comparative example] Next, the embodiment and a comparative example will be compared and explained. Below, a power supply device (such as the power supply device disclosed in Patent Document 1) including a transformer whose primary side is a single-phase two-wire system and whose secondary side is a single-phase three-wire system will be explained as a comparative example. Note that, for the sake of convenience, the following explanation uses the symbols of the components in the embodiment in the explanation of the components in the comparative example.

[0057] In the above comparative example, in a transformer whose primary side is a single-phase two-wire system and whose secondary side is a single-phase three-wire system, it is necessary to secure an output capacitance for generating a first output AC voltage applied between the neutral node N3 and the first output node N4, and an output capacitance for generating a second output AC voltage applied between the neutral node N3 and the second output node N5. Because output capacitance for two phases must be secured in this way, it is difficult to reduce the capacitance of the transformer.

[0058] On the other hand, in the power supply device 10 of the embodiment, in the transformer 16 in which both the primary side and the secondary side are single-phase two-wire, it is only necessary to ensure an output capacity (output capacity for one phase) for generating the first output AC voltage applied between the neutral node N3 and the first output node N4, and it is not necessary to ensure an output capacity for two phases. Therefore, it is possible to reduce the capacity of the transformer 16 compared to the comparative example.

[0059] [Effects of the embodiment] As described above, in the power supply device 10 of the embodiment, both the primary side and the secondary side of the transformer 16 can be single-phase two-wire, so the capacity of the transformer 16 can be reduced compared to when a transformer with a single-phase two-wire primary side and a single-phase three-wire secondary side is used. This allows the weight of the transformer 16 to be reduced, and therefore the weight of the power supply device 10 can be reduced.

[0060] In addition, in the power supply device 10 of the embodiment, the switch 17 is in a conductive state (a state in which the second input node N2 and the first output node N4 are electrically connected) when the output power between the neutral node N3 and the first output node N4 exceeds the capacity of the transformer 16.

[0061] With the above configuration, when the output power between the neutral node N3 and the first output node N4 exceeds the capacity of the transformer 16, the output capacity between the neutral node N3 and the first output node N4 can be changed from "capacity dependent on the capacity of the transformer 16" to "capacity dependent on the larger of the capacity of the transformer 16 and the input capacity." This makes it possible to increase the output capacity between the neutral node N3 and the first output node N4 compared to when the power supply device 10 does not include the switch 17.

[0062] Moreover, the power supply device 10 of the embodiment includes a battery 11 and a conversion unit 12 that converts a DC voltage supplied from the battery 11 into an input AC voltage (an AC voltage applied between a first input node N1 and a second input node N2).

[0063] The above configuration eliminates the need to prepare a temporary power source when testing the power distribution facility 20 and / or the load connected to the power distribution facility 20. This eliminates the need to prepare and remove the temporary power source, thereby reducing the time required to perform the above test.

[0064] (Modification of the embodiment) 2, the primary winding 16a and the secondary winding 16b may be provided to have additive polarity. One end (the dotted side) of the secondary winding 16b is connected to a neutral node N3 via a third wiring LN3. The other end (the non-dotted side) of the secondary winding 16b is connected to a first output node N4 via a fourth wiring LN4. In this example, the transformer 16 is also configured so that the output AC voltage applied between the neutral node N3 and the first output node N4 is in opposite phase to the input AC voltage applied between the first input node N1 and the second input node N2.

[0065] (Other embodiments) In the above description, the following configuration or processing may be performed.

[0066] The power supply device 10 does not necessarily have to include the battery 11 and the conversion unit 12. For example, instead of the battery 11 and the conversion unit 12, the power supply device 10 may include a power supply mechanism that is connected to an AC power source such as a temporary power source and supplies AC voltage supplied from the AC power source to the power supply circuit 13.

[0067] The power supply device 10 may include a mechanism for conducting tests on the power distribution equipment 20 and / or a load connected to the power distribution equipment 20. For example, the power supply device 10 may include components (such as a flicker timer and a neutral grounding confirmation outlet) provided for the tests disclosed in Japanese Patent No. 5,883,363.

[0068] The above embodiments may be combined as appropriate. The above embodiments are essentially preferred examples and are not intended to limit the scope of the present invention, its applications, or its uses. [Industrial Applicability]

[0069] INDUSTRIAL APPLICABILITY As described above, the present invention is useful as a power supply device (particularly as a power supply device for pre-power-receiving inspection). [Explanation of symbols]

[0070] 10 Power supply 11 Batteries 12 Conversion unit 13 Power circuit 14 Storage section 15 Control Unit 16 Transformer 16a Primary winding 16b Secondary winding 17 Switch 20 Power distribution equipment N1 First input node N2 Second input node N3 Neutral Node N4 First output node N5 Second output node L1 First connecting line L2 Second connecting line L10 Neutral connection wire L11 First power supply connection line L12 Second power supply connection line L20 neutral wire L21 1st power line L22 2nd power line

Claims

1. A power supply device connected to a power distribution facility having a neutral line, a first power line, and a second power line, a first input node and a second input node to which an input AC voltage is supplied; a neutral node connected to the neutral conductor; a first output node connected to the first power supply line; a second output node connected to the second power supply line; a transformer having a primary winding connected between the first input node and the second input node and a secondary winding connected between the neutral node and the first output node, wherein the transformer is configured so that an output AC voltage applied between the neutral node and the first output node is in opposite phase to an input AC voltage applied between the first input node and the second input node; a first connection line connecting the first input node and the neutral node; a second connection line connecting the second input node and the second output node; power supply.

2. 2. The power supply device of claim 1, a switch switchable between a conductive state in which the second input node and the first output node are electrically connected and a cut-off state in which the second input node and the first output node are electrically cut off; The switch is in the conducting state when the output power between the neutral node and the first output node exceeds the capacity of the transformer. power supply.

3. 3. The power supply device according to claim 1, Batteries and a conversion unit that converts the DC voltage supplied from the battery into the input AC voltage. power supply.

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