Electrical device

Abstract

To provide an electrical device capable of performing appropriate withstand voltage test without imparting unnecessary stress to the device.SOLUTION: An electrical device comprises: DC wiring connected to an output circuit that outputs DC power; a ground terminal; a ground fault detection circuit provided between the DC wiring and the ground terminal, and configured to detect a ground fault in the output circuit; a housing that houses at least a part of the DC wiring, the ground terminal, and the ground fault detection circuit; and a switching unit that is operable from outside the housing, and switches between electrical connection and non-connection between the DC wiring and the ground terminal.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to electrical devices. [Background technology]

[0002] A DC power supply circuit that supplies DC power is provided with a DC earth fault detection circuit for detecting earth faults in the DC power supply circuit. Patent Document 1, which will be described later, discloses such a circuit configuration. The DC earth fault detection circuit is provided in a voltage divider circuit that resistively divides the positive and negative poles of the DC bus of the DC power supply circuit, and the voltage division midpoint of the voltage divider circuit is grounded via a resistor.

[0003] Electrical equipment that requires the installation of a DC earth fault detection circuit may be required to have a certain withstand voltage performance. When a withstand voltage test is performed to check the withstand voltage performance with a DC earth fault detection circuit installed, leakage current flows in the DC earth fault detection circuit, adversely affecting the withstand voltage test. Furthermore, the leakage current causes the inconvenience of excessive stress on the DC earth fault detection circuit.

[0004] To avoid such inconvenience, it is permitted to perform the withstand voltage test with the DC earth fault detection circuit disconnected. In this case, the electrical equipment is disassembled to the extent that the DC earth fault detection circuit can be accessed, and then the DC earth fault detection circuit is disconnected. After the withstand voltage test is performed in this state, the electrical equipment is reassembled. The electrical equipment is then subjected to a functional inspection, packaged, and shipped. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-60726 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in such a conventional method, there is a risk that some defect (e.g., insulation failure) that affects the withstand voltage may occur during the reassembly process after the withstand voltage test, and such a defect cannot be detected during the withstand voltage test.

[0007] The present disclosure has been made to solve such problems, and one object of the present disclosure is to provide an electrical device that can be appropriately subjected to a voltage withstand test without applying unnecessary stress to the device. [Means for solving the problem]

[0008] An electrical device according to one aspect of the present disclosure includes a DC wiring connected to an output circuit that outputs DC power, a ground terminal, a ground fault detection circuit provided between the DC wiring and the ground terminal and detecting a ground fault in the output circuit, a housing that houses at least a portion of the DC wiring, the ground terminal, and the ground fault detection circuit, and a switching unit that is operable from outside the housing and switches between electrical connection and non-connection between the DC wiring and the ground terminal.

[0009] The present disclosure can be realized not only as an electric device including such a characteristic configuration, but also as other systems, devices, or testing methods including the electric device. Effect of the Invention

[0010] According to the present disclosure, it is possible to provide an electrical device that can be appropriately subjected to a withstand voltage test without applying unnecessary stress to the device. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram for explaining a problem with a withstand voltage test in a state in which a ground fault detection circuit is installed. [Diagram 2] FIG. 2 is a diagram for connecting the circuit configuration of the electric device shown in FIG. [Diagram 3] FIG. 3 is a diagram illustrating an example of a configuration of an electric device according to the first embodiment. [Figure 4]FIG. 4 is a diagram illustrating an example of the configuration of the high voltage circuit illustrated in FIG. [Diagram 5] FIG. 5 is a diagram for explaining a state during a withstand voltage test of the electric device shown in FIG. [Figure 6] FIG. 6 is a perspective view showing an example of the overall configuration of the electric device shown in FIG. [Figure 7] FIG. 7 is a diagram showing an example of the electrical device shown in FIG. 3 with the access cover removed. [Figure 8] FIG. 8 is a diagram showing an example of the configuration of an electric device according to a first modified example. [Figure 9] FIG. 9 is a diagram showing an example of the configuration of an electric device according to the second modification. [Figure 10] FIG. 10 is a diagram for explaining a problem that occurs when a control circuit is provided in the electric device shown in FIG. [Figure 11] FIG. 11 is a diagram illustrating an example of a configuration of an electric device according to the second embodiment. [Figure 12] FIG. 12 is a diagram illustrating an example of a configuration of an electric device according to the second embodiment. [Figure 13] FIG. 13 is a diagram illustrating an example of a configuration of an electric device according to the third embodiment. [Figure 14] FIG. 14 is a diagram illustrating an example of a configuration of an electric device according to the fourth embodiment. [Figure 15] FIG. 15 is a diagram illustrating an example of a configuration of an electric device according to the fourth embodiment. [Figure 16] FIG. 16 is a diagram illustrating a configuration example of a charger / discharger according to the fifth embodiment. [Figure 17] FIG. 17 is a diagram showing an example of the internal configuration of the charger / discharger shown in FIG. [Figure 18] FIG. 18 is a diagram showing a configuration example of an electric device according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] [Description of the embodiments of the present disclosure] Preferred embodiments of the present disclosure will be described below. At least a part of the embodiments described below may be combined in any combination.

[0013] (1) An electrical device according to one aspect of the present disclosure includes a DC wiring connected to an output circuit that outputs DC power, a ground terminal to which a ground wire is connected, a ground fault detection circuit provided between the DC wiring and the ground terminal and configured to detect a ground fault in the output circuit, a housing that houses at least a portion of the DC wiring, the ground terminal, and the ground fault detection circuit, and a switching unit operable from outside the housing for switching between electrical connection and disconnection between the DC wiring and the ground terminal.

[0014] The switching unit can switch between electrical connection and non-connection between the DC wiring and the ground terminal. The switching unit is provided so as to be operable from outside the housing. Therefore, the DC wiring can be disconnected from the ground terminal without disassembling the electrical device. This allows the withstand voltage test to be performed with the ground fault detection circuit disconnected, thereby preventing unnecessary or excessive stress from being applied to the electrical device. Furthermore, the above configuration eliminates the need for a reassembly process after the withstand voltage test, effectively preventing the occurrence of defects that may occur during the reassembly process and affect the withstand voltage. Therefore, according to the electrical device of the present disclosure, the withstand voltage test can be performed appropriately without applying unnecessary stress to the device.

[0015] (2) In the above (1), the housing may have an opening, the switching unit may be operable from outside the housing through the opening, and may further include a cover member that covers the opening. This allows the switching unit to be easily operated from outside the housing. Since the cover member that covers the opening is further included, it is also possible to prevent the user from touching the switching unit.

[0016] (3) In the above (1) or (2), the switching unit may include a switch that switches between electrical connection and disconnection between the DC wiring and the ground terminal by a short-circuiting member, the switch including a first terminal electrically connected to the DC wiring, a second terminal electrically connected to the ground terminal, and a short-circuiting member, such that when the short-circuiting member is inserted into the switch, the first terminal and the second terminal are short-circuited via the short-circuiting member, and when the short-circuiting member is removed from the switch, the first terminal and the second terminal are electrically disconnected. This allows the ground fault detection circuit to be easily disconnected during a withstand voltage test.

[0017] (4) In the above (2), the switching unit may include a switch that switches between electrical connection and non-connection between the DC wiring and the ground terminal by a short-circuiting member, the switch includes a first terminal electrically connected to the DC wiring, a second terminal electrically connected to the ground terminal, and a short-circuiting member, the short-circuiting member being attached to a cover member, the cover member being attached to a housing so that the short-circuiting member is inserted into the switch, and the first terminal and the second terminal are short-circuited via the short-circuiting member, and the cover member being removed from the housing so that the short-circuiting member is removed from the switch, and the electrical connection between the first terminal and the second terminal is cut off. In this way, by removing the cover member from the housing, the DC wiring can be disconnected from the ground terminal. That is, the ground fault detection circuit can be disconnected. Furthermore, since the short-circuiting member is inserted into the switch by attaching the cover member to the housing, it is possible to prevent forgetting to connect the short-circuiting member after a withstand voltage test.

[0018] (5) In the above (1) or (2), the switching unit may include a switch that switches between electrical connection and non-connection between the DC wiring and the ground terminal. This also makes it possible to easily disconnect the DC wiring from the ground terminal during a withstand voltage test.

[0019] (6) In the above (5), the cover member may be attached to the housing so that the switch is in the closed state. This allows the DC wiring to be connected to the ground terminal by attaching the cover member to the housing. Since this prevents the switch from being forgotten to be in the closed state after the voltage withstand test, the ground fault detection circuit can be reliably connected to the ground terminal after the voltage withstand test.

[0020] (7) In any of the above (1) to (6), the switching unit may be provided between the DC wiring and the ground fault detection circuit and configured to switch between electrical connection and non-connection between the DC wiring and the ground terminal via the ground fault detection circuit, thereby enabling the DC wiring to be disconnected from the ground terminal.

[0021] (8) In any of the above (1) to (7), the output circuit may include a conversion circuit that converts AC voltage into DC voltage and outputs the DC voltage to a DC wiring. This makes it possible to appropriately perform a withstand voltage test on an electric device including the conversion circuit without applying unnecessary stress to the device.

[0022] [Details of the embodiment of the present disclosure] Specific examples of electrical devices according to embodiments of the present disclosure will be described below with reference to the drawings. In the following embodiments, the same components are given the same reference numbers. They also have the same functions and names. Therefore, detailed descriptions thereof will not be repeated.

[0023] (First embodiment) [Problems with voltage withstand tests when a ground fault detection circuit is installed] 1, for example, an electric device including a DC wiring 150 connected to an output circuit as a DC power supply may be required to have a predetermined voltage resistance performance. The DC wiring 150 includes two wirings, a first DC wiring 152 and a second DC wiring 154. The first DC wiring 152 is, for example, a positive electrode (P) wire, and the second DC wiring 154 is, for example, a negative electrode (N) wire.

[0024] In such an electric device, it is desirable to install a DC ground fault detection circuit 210 (hereinafter referred to as the "ground fault detection circuit 210"). This can prevent a user from getting an electric shock when a ground fault occurs. The ground fault detection circuit 210 is connected to a voltage division midpoint of a voltage division circuit 160 that resistively divides the first DC wiring 152 (positive electrode) and the second DC wiring 154 (negative electrode). The ground fault detection circuit 210 is also connected to a ground terminal 220 via a ground wire 222 that is a ground conductor. The voltage division circuit 160 includes resistors 162 and 164 that are connected in series between the first DC wiring 152 and the second DC wiring 154. The ground fault detection circuit 210 is connected to a connection point between the resistors 162 and 164. When the ground fault detection circuit 210 detects the occurrence of a ground fault, it outputs a detection signal that notifies the occurrence of the ground fault. More specifically, a control device (not shown) of the electric device or the like receives the detection signal from the ground fault detection circuit 210 and cuts off the power supply to the DC wiring, thereby eliminating the risk of electric shock.

[0025] The withstand voltage test is, for example, an AC withstand voltage test, and inspects whether the equipment is damaged or the insulation performance is deteriorated. The withstand voltage tester 50 is connected to two DC wirings (the first DC wiring 152 and the second DC wiring 154) and the ground terminal 220, and applies a predetermined test voltage to the electric equipment. When the withstand voltage test is performed with the ground fault detection circuit 210 connected, a leakage current flows along the path indicated by the dashed arrow. This leakage current adversely affects the withstand voltage test. Specifically, the leakage current may cause a determination that the equipment does not have a predetermined withstand voltage performance (insulation performance). Furthermore, the leakage current may flow into the ground fault detection circuit 210, which may cause excessive stress on the ground fault detection circuit 210.

[0026] Therefore, as described above, in the withstand voltage test, it is sometimes permitted to carry out the withstand voltage test with the ground fault detection circuit 210 disconnected.

[0027] 2, the circuit configuration of the electric device shown in FIG. 1 includes a high voltage circuit 100 and a ground circuit 200. The high voltage circuit 100 includes, for example, an output circuit, a DC wiring 150, and a voltage dividing circuit 160. The ground circuit 200 includes, for example, a ground fault detection circuit 210 and a ground terminal 220. The disconnection point of the ground fault detection circuit 210 is a position where electrical insulation between the high voltage circuit 100 and the ground circuit 200 or the ground is ensured. Such a disconnection point may be a connection portion (point A) between the high voltage circuit 100 and the ground circuit 200, or a connection portion (point B) between the ground fault detection circuit 210 and the ground terminal 220 in the ground circuit 200. In this case, disconnection of the ground fault detection circuit 210 includes a configuration for disconnecting the ground fault detection circuit 210 from the high voltage circuit 100 (DC wiring 150) and a configuration for disconnecting the ground fault detection circuit 210 from the ground terminal 220.

[0028] [Overall configuration] With reference to FIG. 3, the electric device 20 according to the present embodiment includes a high voltage circuit 100, a ground circuit 200, a switching unit 300, and a housing 400. With reference to FIG. 4, the high voltage circuit 100 includes an output circuit 110 and a DC wiring 150 connected to the output circuit 110. The output circuit 110 is, for example, a DC power source that outputs DC power. When the output circuit 110 is the main circuit of the electric device 20, the DC wiring 150 can also be called a main circuit wiring. As described above, the DC wiring 150 includes a first DC wiring 152 (positive electrode) and a second DC wiring 154 (negative electrode). With reference again to FIG. 3, the high voltage circuit 100 further includes a voltage dividing circuit 160. As described above, the voltage dividing circuit 160 includes a resistor 162 and a resistor 164 connected in series between the first DC wiring 152 and the second DC wiring 154.

[0029] The ground circuit 200 includes a ground fault detection circuit 210 and a ground terminal 220. The ground circuit 200 may include a control power supply. A ground wire 222 is connected to the ground terminal 220, and the ground fault detection circuit 210 and the ground terminal 220 are electrically connected via the ground wire 222. The switching unit 300 switches between an electrical connection and a disconnection between the DC wiring 150 and the ground terminal 220. When the switching unit 300 is an object to be operated when switching between an electrical connection and a disconnection, it can also be called an "operation unit."

[0030] In this embodiment, the switching unit 300 separates the high voltage circuit 100 from the ground terminal 220 at a connection portion (point A shown in FIG. 2) between the high voltage circuit 100 and the ground circuit 200. The switching unit 300 includes a switch 310 that switches between electrical connection and non-connection between the DC wiring 150 (high voltage circuit 100) and the ground terminal 220 by inserting and removing a short pin 314 as a short-circuiting member. The switch 310 includes a switch body 312 and a short pin 314 that is inserted and removed from the switch body 312. The switch body 312 is provided with a first terminal 316 and a second terminal 318. The first terminal 316 is connected to a voltage division midpoint of the voltage division circuit 160 (a connection point between the resistor 162 and the resistor 164). That is, the first terminal 316 is electrically connected to the DC wiring 150 via the voltage division circuit 160. The second terminal 318 is connected to the ground fault detection circuit 210. That is, the second terminal 318 is electrically connected to the ground terminal 220 via the ground fault detection circuit 210.

[0031] The short pin 314 shorts the first terminal 316 and the second terminal 318 when inserted into the switch body 312. This causes the DC wiring 150 and the ground fault detection circuit 210 to be electrically connected to each other.

[0032] 5, when the short pin 314 (see FIG. 3) is removed from the switch body 312, the electrical connection between the first terminal 316 and the second terminal 318 is cut off (opened). This cuts off the electrical connection between the DC wiring 150 and the ground fault detection circuit 210. Therefore, the electrical connection between the DC wiring 150 and the ground terminal 220 is also cut off. That is, the high voltage circuit 100 is electrically insulated from the ground or the ground circuit 200. By performing a withstand voltage test in this state, the occurrence of leakage current via the ground fault detection circuit 210 is prevented.

[0033] 3 again, the switch 310 (switching unit 300) is provided so as to be operable from outside the housing 400. In other words, the short pin 314 in the switch 310 can be inserted and removed without disassembling the electric device 20. That is, the electric device 20 has a configuration in which the electrical connection between the DC wiring 150 and the ground terminal 220 can be cut off from outside the housing 400 in an assembled state. For example, a connector for connecting an interface (I / F) or a terminal block 320 may be provided near the switch 310.

[0034] Note that switch 310 is covered (protected) by access cover 410 to prevent the user from touching it, for example. Therefore, access cover 410 needs to be removed in order to operate switch 310. However, removal of access cover 410 is not included in disassembly of electric device 20 here. In other words, the state in which access cover 410 is removed can also be considered as the product assembly state.

[0035] The housing 400 houses at least a part of the DC wiring 150, the ground terminal 220, and the ground fault detection circuit 210. That is, the housing 400 houses the high voltage circuit 100 and the ground circuit 200. A part of the DC wiring 150 may be drawn out from the housing 400 to the outside. With reference to FIG. 6, the housing 400 has a rectangular box shape. The housing 400 has, for example, a front surface 420, a rear surface 422, side surfaces 424 and 426, a top surface (top surface) 428, and a bottom surface (bottom surface) 430. For example, the front surface 420 is formed of a front panel, and the front panel is removed when the electric device 20 is disassembled. For example, an opening 432 is provided in the side surface 426 of the housing 400.

[0036] 7, a terminal block 320 and the like are provided near an opening 432 inside the housing 400 for wiring on-site when the electrical device 20 is installed. A switch 310 (see FIG. 3) is also provided so as to be exposed from the opening 432. Therefore, the switch 310 can be operated from outside the housing 400 through the opening 432. An access cover 410 (see FIG. 6) is attached to the housing 400 so as to cover the opening 432. The access cover 410 can be attached, for example, by screwing.

[0037] [Procedure for voltage resistance test] When a withstand voltage test is performed, in the assembled product state shown in Fig. 3, the access cover 410 is removed and then the short pin 314 is pulled out. This disconnects the high voltage circuit 100 from the ground terminal 220. Referring to Fig. 5, in this state, an AC withstand voltage test is performed using a withstand voltage tester 50, thereby preventing leakage current from flowing through the ground fault detection circuit 210. This makes it possible to prevent unnecessary or excessive stress from being applied to the ground fault detection circuit 210. In addition, the withstand voltage test can be performed appropriately.

[0038] [Processing after voltage resistance test] 3, after the withstand voltage test is completed, the short pin 314 is inserted into the switch body 312, whereby the DC wiring 150 and the ground fault detection circuit 210 are electrically connected, and the ground fault detection circuit 210 is electrically connected to the ground terminal 220. As a result, when a ground fault occurs in the main circuit (the output circuit 110 (see FIG. 4)), the ground fault can be detected by the ground fault detection circuit 210.

[0039] As described above, according to the electric device 20 of the present embodiment, the switching unit 300 (switch 310) can switch between electrical connection and non-connection between the DC wiring 150 and the ground terminal 220. The switching unit 300 is provided so as to be operable from the outside of the housing 400. Therefore, the ground fault detection circuit 210 can be disconnected without disassembling the electric device 20, except for removing the access cover 410. Since the withstand voltage test can be performed with the ground fault detection circuit 210 disconnected, it is possible to prevent unnecessary or excessive stress from being applied to the electric device 20. Furthermore, since the above-mentioned configuration eliminates the need for a reassembly process after the withstand voltage test, it is possible to effectively prevent the occurrence of defects (e.g., insulation failure) that may occur in the reassembly process and affect the withstand voltage. Therefore, the withstand voltage test can be appropriately performed without applying unnecessary stress to the electric device 20.

[0040] The housing 400 has an opening 432, and the switching unit 300 is provided so as to be operable from outside the housing 400 via the opening 432. This opening 432 is covered by an access cover 410. This makes it possible to easily operate the switching unit 300 from outside the housing 400. Since a cover member that covers the opening is further included, it is also possible to prevent the user from touching the switching unit 300.

[0041] As the switching unit 300, a switch 310 that switches between electrical connection and non-connection between the DC wiring 150 and the ground terminal 220 by a short pin 314 can be used. The switch 310 includes a first terminal 316 electrically connected to the DC wiring 150, a second terminal 318 electrically connected to the ground terminal 220, and a short pin 314. When the short pin 314 is inserted into the switch 310 (switch body 312), the first terminal 316 and the second terminal 318 are short-circuited via the short pin 314. On the other hand, when the short pin 314 is removed from the switch 310 (switch body 312), the electrical connection between the first terminal 316 and the second terminal 318 is cut off. This makes it possible to easily disconnect the ground fault detection circuit 210 from the ground terminal 220 during a withstand voltage test.

[0042] The above-mentioned switch may use a short-circuiting member other than a short pin. For example, the switch may use a short-circuiting wire or a short-circuiting bus bar as the short-circuiting member. That is, the switch may be configured to switch between electrical connection and non-connection between the DC wiring 150 (high voltage circuit 100) and the ground terminal 220 by attaching and detaching the short-circuiting wire or the short-circuiting bus bar with a screw.

[0043] (First Modification) In the above first embodiment, an example has been shown in which the high voltage circuit is separated from the ground terminal at the connection portion between the high voltage circuit and the ground circuit (point A shown in FIG. 2). However, the present disclosure is not limited to such an embodiment. The separation point may be, for example, the connection portion between the ground fault detection circuit in the ground circuit and the ground terminal (point B shown in FIG. 2).

[0044] 8, an electric device 20A according to the first modification includes components similar to those of the above-described electric device 20 (see FIG. 3). However, the electric device 20A differs from the above-described first embodiment in the location that is disconnected by the switch 310.

[0045] Specifically, a first terminal 316 of the switch 310 is connected to the DC wiring 150 via the voltage divider circuit 160 and the ground fault detection circuit 210. A second terminal 318 of the switch 310 is connected to the ground terminal 220. In this configuration, when the short pin 314 is removed from the switch body 312, the electrical connection between the ground fault detection circuit 210 and the ground terminal 220 is cut off, and thus the electrical connection between the DC wiring 150 and the ground terminal 220 is cut off.

[0046] (Second Modification) The first embodiment may further include a control circuit that determines the occurrence of a ground fault based on the output from the ground fault detection circuit. Such a configuration will be described in the second modified example.

[0047] 9, an electric device 20B according to a second modification further includes a control circuit 240 in addition to the configuration of the above-described first embodiment. The control circuit 240 is connected to a ground fault detection circuit 210. The control circuit 240 is grounded. The ground fault detection circuit 210 outputs a detection signal to the control circuit 240. The control circuit 240 includes a processor such as a microcomputer, and determines the occurrence of a ground fault based on the detection signal from the ground fault detection circuit 210.

[0048] In this configuration, the electrical connection between the DC wiring 150 and the ground fault detection circuit 210 is cut off by removing the short pin 314 from the switch body 312. Since the control circuit 240 is connected to the ground fault detection circuit 210, the electrical connection between the DC wiring 150 and the control circuit 240 is also cut off. This cuts off the electrical connection between the DC wiring 150 and the ground terminal 220. In other words, the high voltage circuit 100 is electrically isolated from the ground or the ground circuit 200.

[0049] 8 to 10, terminal block 320 (see FIG. 3) and the like for connecting wires on-site during installation work of electrical equipment are omitted.

[0050] (Second embodiment) 11, electric device 22 according to the present embodiment differs from the first embodiment in that short pin 314 as a short-circuiting member is fixed to access cover 410. When access cover 410 is made of a conductive material such as a metal material, short pin 314 is attached in a state insulated from access cover 410. As an insulation method, for example, an insulating resin member may be interposed between short pin 314 and access cover 410.

[0051] 12, since the short pin 314 is fixed to the access cover 410, by removing the access cover 410, the short pin 314 is pulled out from the switch body 312. By simply removing the access cover 410, the high voltage circuit 100 (DC wiring 150) is disconnected from the ground terminal 220. This makes it possible to carry out a withstand voltage test.

[0052] Meanwhile, by attaching access cover 410 to housing 400, short pin 314 is inserted (plugged) into switch body 312. Therefore, simply by attaching access cover 410 after the withstand voltage test is performed, it becomes possible for ground fault detection circuit 210 to detect a ground fault.

[0053] In this manner, according to the electric device 22 of the present embodiment, by attaching the access cover 410 to the housing 400, the short pin 314 is inserted into the switch 310, and the first terminal 316 and the second terminal 318 are short-circuited via the short pin 314. On the other hand, when the access cover 410 is removed from the housing 400, the short pin 314 is removed from the switch 310, and the electrical connection between the first terminal 316 and the second terminal 318 is cut off. As a result, by removing the access cover 410 from the housing 400, the ground fault detection circuit 210 can be disconnected. Furthermore, since the short pin 314 is inserted into the switch 310 by attaching the access cover 410 to the housing 400, it is possible to prevent forgetting to connect the short pin 314 after the withstand voltage test.

[0054] Other configurations and effects are the same as those of the first embodiment. In the above embodiment, a short-circuiting member other than a short pin may be used as long as the short-circuiting member can short-circuit both terminals of the switch by attaching the access cover and can open both terminals of the switch by removing the access cover.

[0055] (Third embodiment) 13, electric device 24 according to the present embodiment includes a switching unit 300A instead of switching unit 300 (see FIG. 3). This switching unit 300A includes a switch 330 that is a switch that opens and closes (on / off) an electric circuit of a power circuit or an electric circuit. That is, electric device 24 according to the present embodiment differs from the first embodiment in that it includes a switch 330 that opens and closes an electric circuit instead of a switch that includes a short pin.

[0056] The switch 330 includes a first terminal 332 and a second terminal 334. The first terminal 332 is connected to a voltage division midpoint (a connection point between the resistor 162 and the resistor 164) of the voltage divider circuit 160. The second terminal 334 is connected to the ground fault detection circuit 210. That is, the second terminal 334 is electrically connected to the ground terminal 220 via the ground fault detection circuit 210.

[0057] When the switch 330 is turned on, the first terminal 332 and the second terminal 334 are electrically connected. This electrically connects the DC wiring 150 and the ground fault detection circuit 210. When the switch 330 is turned off, the electrical connection between the first terminal 332 and the second terminal 334 is cut off. This electrically disconnects the DC wiring 150 and the ground fault detection circuit 210. Therefore, the electrical connection between the DC wiring 150 and the ground terminal 220 is also cut off. That is, the high voltage circuit 100 is electrically isolated from the ground or the ground circuit 200.

[0058] In this manner, according to the electric device 24 of the present embodiment, the DC wiring 150 and the ground terminal 220 can be electrically connected and disconnected by operating the switch 330. The switch 330 is provided so as to be operable from the outside of the housing 400. Therefore, the ground fault detection circuit 210 can be disconnected without disassembling the electric device 24, except for removing the access cover 410. Since the withstand voltage test can be performed with the ground fault detection circuit 210 disconnected, it is possible to prevent unnecessary or excessive stress from being applied to the electric device 24. Furthermore, since the above-mentioned configuration eliminates the need for a reassembly process after the withstand voltage test, it is possible to effectively prevent the occurrence of defects (e.g., insulation failure) that may occur in the reassembly process and affect the withstand voltage. Therefore, the withstand voltage test can be appropriately performed without applying unnecessary stress to the electric device 24.

[0059] By turning on the switch 330, the DC wiring 150 and the ground fault detection circuit 210 are electrically connected, and the ground fault detection circuit 210 is electrically connected to the ground terminal 220. This allows the ground fault detection circuit 210 to detect a ground fault in the output circuit 110 (see FIG. 4).

[0060] The other configurations and effects are similar to those of the first embodiment.

[0061] (Fourth embodiment) 14, electrical device 24A according to the present embodiment differs from the third embodiment in that switch 330 is configured to be turned on (closed state) by attaching access cover 410 to housing 400.

[0062] A biasing member (biasing portion) 412 for biasing the switch of switch 330 to the ON side is provided inside access cover 410. When performing a withstand voltage test, access cover 410 is removed from housing 400, and switch 330 is turned OFF. This disconnects the electrical connection between first terminal 332 and second terminal 334, allowing the withstand voltage test to be performed in a state in which ground fault detection circuit 210 is disconnected.

[0063] 15, by attaching access cover 410 to housing 400, switch 330 is turned on (closed state) by biasing member 412. This shorts first terminal 332 and second terminal 334. Therefore, simply attaching access cover 410 after carrying out the withstand voltage test enables ground fault detection circuit 210 to detect a ground fault.

[0064] The other configurations and effects are the same as those of the third embodiment.

[0065] (Fifth embodiment) An example will be described in which the configuration of an electrical device according to the present disclosure is applied to a charger for charging an electric vehicle (e.g., an electric car). The charger has a function of charging the on-board storage battery of the electric vehicle. In addition to the charging function of charging the on-board storage battery of the electric vehicle, some chargers also have a discharging function of discharging the power of the on-board storage battery and supplying it to a household load or the like. Such a charger is called a "charger / discharger." A charger / discharger will be described below as a specific example of an electrical device.

[0066] 16, charger / discharger 26 according to this embodiment supplies DC power to, for example, on-board storage battery 72 of electric vehicle 70. Charger / discharger 26 includes a housing 400 and a charging cable 150A drawn out from housing 400 to the outside. Housing 400 has a rectangular box shape including a front panel 420A. A charging connector 170 is provided at the end of charging cable 150A. This charging connector 170 is connected to an inlet (not shown) of electric vehicle 70 when charging (or discharging) on-board storage battery 72 of electric vehicle 70.

[0067] A front panel 420A of the charger / discharger 26 is provided with an operation panel 440 for operating the charger / discharger 26.

[0068] 17, the charger / discharger 26 includes a high voltage circuit 100A, a ground circuit 200, a switching unit 300, and a housing 400. The high voltage circuit 100A includes a conversion circuit 120 as an output circuit, a control device 130 that controls the driving of the conversion circuit 120, a DC wiring 150 connected to the conversion circuit 120, and a voltage dividing circuit 160 that divides the voltage between the DC wiring 150. The conversion circuit 120 is a bidirectional power conversion circuit, and includes an AC / DC converter 122 and an isolated DC / DC converter 124. The AC / DC converter 122 side of the conversion circuit 120 is connected to the power system 140 via AC terminals 126 and 128. The isolated DC / DC converter 124 side of the conversion circuit 120 is connected to the DC wiring 150.

[0069] Charger / discharger 26 receives AC power of 100V AC or 200V AC from power system 140. AC / DC converter 122 of conversion circuit 120 converts the input AC power into DC power and outputs it to isolated DC / DC converter 124. Isolated DC / DC converter 124 converts (boosts) DC power from AC / DC converter 122 into DC power of a predetermined voltage (e.g., DC 400V) and outputs it to DC wiring 150. A part of DC wiring 150 is drawn out from housing 400 to the outside and used as charging cable 150A. The DC power output from conversion circuit 120 is supplied to electric vehicle 70 (see FIG. 15 ) via charging connector 170. As a result, on-board storage battery 72 of electric vehicle 70 is charged.

[0070] When the vehicle-mounted storage battery 72 (see FIG. 16) is discharged, the reverse operation to the above is performed. That is, DC power from the vehicle-mounted storage battery 72 is input to the isolated DC / DC converter 124 of the conversion circuit 120 via the DC wiring 150. The isolated DC / DC converter 124 steps down the voltage of the input DC power to a predetermined voltage and outputs it to the AC / DC converter 122. The AC / DC converter 122 converts the input DC power to AC power and outputs it to the power grid 140. The power of the vehicle-mounted storage battery 72 is supplied to household loads such as electrical appliances, for example.

[0071] As described above, the DC wiring 150 includes the first DC wiring 152 and the second DC wiring 154. The voltage dividing circuit 160 includes the resistors 162 and 164 connected in series between the first DC wiring 152 and the second DC wiring 154.

[0072] The ground circuit 200 includes a ground fault detection circuit 210 and a ground terminal 220. The ground fault detection circuit 210 is connected to the ground terminal 220 via a ground wire 222. The ground terminal 220 is grounded. A detection signal from the ground fault detection circuit 210 is input to, for example, a control device 130. The control device 130 includes a processor such as a microcomputer, and controls the driving of the AC / DC converter 122 and the isolated DC / DC converter 124, and determines the occurrence of a ground fault based on the detection signal from the ground fault detection circuit 210. The control device 130 may be configured to stop the conversion circuit 120 and cut off the connection to the on-board storage battery 72 of the electric vehicle 70 when the occurrence of a ground fault is detected based on the detection signal from the ground fault detection circuit 210.

[0073] As the switching unit 300, for example, a switch 310 is used. A first terminal 316 of the switch 310 is connected to a voltage division midpoint (a connection point between the resistor 162 and the resistor 164) of the voltage divider circuit 160. A second terminal 318 of the switch 310 is connected to the ground fault detection circuit 210. The short pin 314 shorts (shortens) the first terminal 316 and the second terminal 318 when inserted into the switch body 312. This electrically connects the DC wiring 150 and the ground fault detection circuit 210.

[0074] When the short pin 314 is removed from the switch body 312, the electrical connection between the first terminal 316 and the second terminal 318 is cut off (opened). This cuts off the electrical connection between the DC wiring 150 and the ground fault detection circuit 210. Therefore, the electrical connection between the DC wiring 150 and the ground terminal 220 is also cut off. In other words, the high voltage circuit 100A is electrically isolated from the ground or the ground circuit 200.

[0075] The switch 310 (switching unit 300) is provided so as to be operable from outside the housing 400. Specifically, the switch 310 (switching unit 300) is configured so as to be operable from outside the housing 400 through an opening provided in the housing 400. The switch 310 is covered (protected) by the access cover 410.

[0076] According to the charger / discharger 26 of this embodiment, the switching unit 300 (switch 310) can switch between electrical connection and non-connection between the DC wiring 150 and the ground terminal 220. Therefore, the withstand voltage test can be performed with the ground fault detection circuit 210 disconnected, so that unnecessary or excessive stress can be prevented from being applied to the charger / discharger 26. Furthermore, the above configuration eliminates the need for a reassembly process after the withstand voltage test, so that the occurrence of defects that may occur in the reassembly process and affect the withstand voltage (e.g., insulation failure) can be effectively prevented. Therefore, the withstand voltage test can be performed appropriately without applying unnecessary stress to the charger / discharger 26.

[0077] The other configurations and effects are similar to those of the first embodiment.

[0078] (Modification) In the above embodiment, an example in which the ground fault detection device is connected to the voltage dividing circuit has been described. However, the present disclosure is not limited to such an embodiment. For example, the ground fault detection device may be provided with a voltage dividing circuit.

[0079] In the above embodiment, an example has been shown in which the switching unit can be operated from outside the housing through an opening provided in the housing. However, the present disclosure is not limited to such an embodiment. For example, the switching unit may be installed on the outer surface of the housing without providing an opening in the housing.

[0080] In the above-described embodiment, the electrical device is not limited to a charger / discharger. The electrical device may be, for example, a charger other than a charger / discharger, or may be a device other than a charger / discharger and a charger.

[0081] In the above third embodiment, an example is shown in which a switch is provided near an opening provided in the housing so that the switch can be operated from outside the housing. However, the present disclosure is not limited to such an embodiment. For example, the switch may be installed inside the housing (for example, at a position away from the opening) and an electrical signal may be transmitted to control the switch. The instruction to transmit the electrical signal, i.e., the instruction to turn the switch on and off, may be performed, for example, by operating an operation panel provided outside the housing.

[0082] In the above fourth embodiment, an example in which the switch is closed by the biasing member provided on the access cover is shown. However, the present disclosure is not limited to such an embodiment. As long as the switch can be closed by attaching the access cover to the housing, a method other than the method using the biasing member may be used. For example, a switch may be provided that is turned on when the access cover is attached to the housing and turned off when the access cover is removed from the housing, and the switch may be turned on (closed state) or off (open state) by turning on and off the switch. As a result, when the access cover is removed from the housing, the switch is opened and the ground fault detection circuit is disconnected. On the other hand, when the access cover is attached to the housing, the switch is closed and the ground fault detection circuit is in a state in which it can detect a ground fault. In this case, the installation position of the switch is not particularly limited. For example, the switch may be installed inside the housing (for example, at a position away from the opening). Below, a configuration example of an electric device to which such a configuration is applied will be described.

[0083] 18, electric device 24B according to the modified example includes switching unit 300B instead of switching unit 300A (see FIG. 13). Switching unit 300B includes switch 330A. Switch 330A includes relay 302. Relay 302 is provided, for example, between voltage dividing circuit 160 and ground fault detection circuit 210. By turning relay 302 on and off, electrical connection and disconnection between DC wiring 150 and ground terminal 220 is switched. The on and off of relay 302 is controlled by switch 304. Switch 304 is provided, for example, in a portion covered by access cover 410.

[0084] When access cover 410 is attached to housing 400, switch 304 is turned on by pressing portion 414 of access cover 410. Turning switch 304 on turns on relay 302, and electrically connects DC wiring 150 and ground terminal 220. This enables detection of a ground fault by ground fault detection circuit 210. On the other hand, when access cover 410 is removed from housing 400, switch 304 is turned off. Turning switch 304 off turns relay 302 off, and DC wiring 150 is disconnected from ground terminal 220. This disconnects ground fault detection circuit 210.

[0085] In the fifth embodiment, a switch shorted by a short pin is used as the switching unit. However, the present disclosure is not limited to such an embodiment. The switching unit may have the configuration shown in the first to fourth embodiments.

[0086] The electric device, charger / discharger, or charger shown in the above embodiment can also be configured as the above-mentioned first or second modified example.

[0087] Embodiments obtained by appropriately combining the techniques disclosed above are also included in the technical scope of the present disclosure.

[0088] The embodiments disclosed herein are merely examples, and the present disclosure is not limited to the above-described embodiments. The scope of the present disclosure is indicated by the claims of the claims after taking into consideration the description of the detailed description of the invention, and includes all modifications within the meaning and scope equivalent to the wording described therein. [Explanation of symbols]

[0089] 20, 20A, 20B, 22, 24, 24A, 24B Electrical Equipment 26 Charger / discharger 50 Voltage resistance tester 70 Electric Vehicles 72 Vehicle storage battery 100, 100A high voltage circuit 110 Output circuit 120 Conversion circuit 122 AC / DC converter 124 Isolated DC / DC Converter 126, 128 AC terminal 130 Control device 140 Power system 150 DC wiring 150A charging cable 152 1st DC wiring 154 2nd DC wiring 160 Voltage divider circuit 162, 164 Resistor 170 Charging connector 200 Ground circuit 210 Earth fault detection circuit 220 Ground terminal 222 Ground wire 240 Control circuit 300, 300A, 300B Switching Unit 310 Switch 312 Switch body 314 Short pin 316, 332 1st terminal 318, 334 2nd terminal 320 terminal block 330, 330A switch 302 Relay 304 Switch 400 cabinet 410 Access Cover 412 Pressing member 414 Pressing part 420 front 420A Front Panel 422 Back 424, 426 Side 428 Top 430 Bottom surface 432 Opening 440 Operation Panel

Claims

1. A DC wiring connected to an output circuit that outputs DC power; A ground terminal; a ground fault detection circuit provided between the DC wiring and the ground terminal to detect a ground fault in the output circuit; a housing that houses at least a portion of the DC wiring, the ground terminal, and the ground fault detection circuit; a switching unit operable from outside the housing, the switching unit switching between electrical connection and disconnection between the DC wiring and the ground terminal.

2. The housing has an opening, the switching unit is operable from the outside of the housing through the opening, The electrical device according to claim 1 , further comprising a cover member covering the opening.

3. the switching unit includes a switch that switches between electrical connection and non-connection between the DC wiring and the ground terminal using a short-circuiting member, the switch includes a first terminal electrically connected to the DC wiring, a second terminal electrically connected to the ground terminal, and the short-circuit member; When the short-circuiting member is inserted into the switch, the first terminal and the second terminal are short-circuited via the short-circuiting member, 3 . The electric device according to claim 1 , wherein when the short-circuiting member is removed from the switch, the first terminal and the second terminal are electrically disconnected.

4. the switching unit includes a switch that switches between electrical connection and non-connection between the DC wiring and the ground terminal using a short-circuiting member, the switch includes a first terminal electrically connected to the DC wiring, a second terminal electrically connected to the ground terminal, and the short-circuit member; the short-circuit member is attached to the cover member, When the cover member is attached to the housing, the short-circuit member is inserted into the switch, and the first terminal and the second terminal are short-circuited via the short-circuit member. The electrical device according to claim 2 , wherein when the cover member is removed from the housing, the short-circuit member is pulled out from the switch, and the first terminal and the second terminal are electrically disconnected.

5. 3. The electric device according to claim 1, wherein the switching unit includes a switch that switches between electrical connection and disconnection between the DC wiring and the ground terminal.

6. The electrical device according to claim 5 , wherein the switch is in a closed state when the cover member is attached to the housing.

7. 3. The electric device according to claim 1, wherein the switching unit is provided between the DC wiring and the ground fault detection circuit and switches between electrical connection and non-connection between the DC wiring and the ground terminal via the ground fault detection circuit.

8. 3. The electric device according to claim 1, wherein the output circuit includes a conversion circuit that converts an AC voltage into a DC voltage and outputs the DC voltage to the DC wiring.

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