Power Conversion Equipment

Abstract

To provide a power conversion device capable of detecting electric leak of AC power on which power conversion is performed.SOLUTION: A power conversion device comprises an input unit 1, a power storage unit 2, a power conversion unit 3, an output unit 4, an output switching unit 5, a leakage current detection unit 6 and a control unit 7. First AC power is inputted from a commercial power source 200 to the input unit 1. The power storage unit 2 stores DC power. The power conversion unit 3 converts DC power into second AC power. A load is electrically connected to the output unit 4. The output switching unit 5 transfers the first AC power and the second AC power to the output unit 4 in a switchable manner. The leakage current detection unit 6 detects a leakage current of the second AC power. The control unit 7 detects electric leakage on the basis of a result of the leak current detection unit 6 and stops the power conversion unit 3 in a case where the electric leakage is detected.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates generally to a power conversion device, and more particularly to a power conversion device that switchably outputs AC power from a commercial power source and AC power that has been converted from the AC power. [Background technology]

[0002] Patent Document 1 discloses a power control device. This power control device includes an inverter, a first interconnection relay, a second interconnection relay, a reference potential relay, a voltage sensor, and a control unit. The control unit determines whether or not the state of each of the first interconnection relay and the second interconnection relay is normal based on a voltage value measured by the voltage sensor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-317598 A Summary of the Invention [Problem to be solved by the invention]

[0004] The power control device described in Patent Document 1 has a problem in that when a leakage occurs in the AC power converted by the inverter, the leakage cannot be detected.

[0005] An object of the present disclosure is to provide a power conversion device capable of detecting leakage current in AC power that has been converted. [Means for solving the problem]

[0006] A power conversion device according to an aspect of the present disclosure includes an input unit, a power storage unit, a power conversion unit, an output unit, an output switching unit, a leakage current detection unit, and a control unit. A voltage detection unit;The input unit receives a first AC power from a commercial power source. The power storage unit stores DC power. The power conversion unit converts the DC power to second AC power. The output unit is electrically connected to a load. The output switching unit transmits the first AC power and the second AC power to the output unit in a switchable manner. The leakage current detection unit detects a leakage current of the second AC power. The control unit detects a leakage current based on a result of the leakage current detection unit, and stops the power conversion unit when the leakage current is detected. The voltage detection unit detects an internal voltage of at least one of the output switching units. The output switching unit includes a first relay unit provided between the input unit and the output unit, and a second relay unit provided between the power conversion unit and the output unit. The first relay unit makes and breaks an electrical connection between the input unit and the output unit. The second relay unit makes and breaks an electrical connection between the power conversion unit and the output unit. The first relay unit includes a plurality of first contact units. The second relay unit includes a plurality of second contact units. The plurality of first contact units are connected in series between the input unit and the output unit. The plurality of second contact units are connected in series between the power conversion unit and the output unit. The voltage detection unit includes a first voltage detection unit and a second voltage detection unit. The first voltage detection unit detects a first internal voltage, which is a voltage of an electric path between a pair of first contact units among the plurality of first contact units, as the internal voltage. The second voltage detection unit detects, as the internal voltage, a second internal voltage which is a voltage of an electric path between a pair of second contact units among the plurality of second contact units. The control unit includes a signal generation unit, a first drive control unit, and a second drive control unit. The signal generation unit outputs a first control signal for controlling the first relay unit and a second control signal for controlling the second relay unit. The first voltage detection unit outputs a detection result of the first internal voltage as a first detection signal. The second voltage detection unit outputs a detection result of the second internal voltage as a second detection signal. The first drive control unit drives the plurality of first contact units based on the second detection signal and the first control signal. The second drive control unit drives the plurality of second contact units based on the first detection signal and the second control signal. Effect of the Invention

[0007] According to the present disclosure, there is an advantage that leakage current in AC power that has been converted can be detected. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram showing a schematic configuration of a power conversion device according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a more detailed circuit configuration diagram of the power conversion device. [Diagram 3] FIG. 3 is a flowchart showing operations from leakage current detection to stopping of the power conversion unit of the power conversion device. [Figure 4] FIG. 4 is a flowchart showing an operation of switching the output of the power conversion device from the first AC power to the second AC power. [Diagram 5] FIG. 5 is a flowchart showing an operation of switching the output of the power conversion device from the second AC power to the first AC power. [Figure 6] FIG. 6 is a block diagram showing a schematic configuration of a power conversion device according to a modification of the above embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (Embodiment) (1) Overview As shown in FIG. 1, the power conversion device 100 according to this embodiment includes an input unit 1, a power storage unit 2, a power conversion unit 3, an output unit 4, an output switching unit 5, a leakage current detection unit 6, and a control unit 7.

[0010] In the power conversion device 100 according to this embodiment, when the input unit 1 is electrically connected to the commercial power source 200, a first AC power is input from the commercial power source 200 to the input unit 1. Furthermore, the power conversion unit 3 converts the DC power stored in the power storage unit 2 into the second AC power. Thereafter, the output switching unit 5 transmits to the output unit 4, in a switchable manner, the first AC power input to the input unit 1 and the second AC power converted by the power conversion unit 3.

[0011] The leakage current detection unit 6 detects a leakage current of the second AC power, and the control unit 7 detects a leakage of the second AC power based on a detection result of the leakage current detection unit 6. When a leakage of the second AC power is detected, the control unit 7 stops the power conversion unit 3.

[0012] (2)Details The power conversion device 100 of this embodiment will be described in detail below with reference to Figures 1 and 2. The power conversion device 100 is used in each dwelling unit of an apartment building, a detached house, a factory, an office, and the like.

[0013] The input unit 1 can be electrically connected to the commercial power source 200. As shown in FIG. 2, when the input unit 1 is electrically connected to the commercial power source 200, a first AC power is input from the commercial power source 200 to the input unit 1. The input unit 1 includes a live input terminal 11 connected to a non-grounded electrode of the commercial power source 200, a neutral input terminal 12 connected to a grounded electrode of the commercial power source 200, and a ground input terminal 13 connected to a grounded electrode of the commercial power source 200. The power conversion device 100 further includes a first live electric circuit C11, a first neutral electric circuit C12, and a first ground electric circuit C13 connected to the live input terminal 11, the neutral input terminal 12, and the ground input terminal 13, respectively. The first ground electric circuit C13 is grounded to a housing of the power conversion device 100. The input unit 1 of this embodiment preferably includes an input plug. For example, the first AC power is input to the input unit 1 by inserting the input plug into an outlet provided in each dwelling unit of an apartment building, a detached house, a factory, an office, or the like. That is, it is preferable that the input unit 1 includes an input plug or a terminal, etc., and the electrical connection state between the input unit 1 and the commercial power source 200 can be switched between connected and disconnected.

[0014] The power storage unit 2 stores DC power. The power conversion unit 3 converts the DC power stored in the power storage unit 2 into second AC power. The power conversion unit 3 supplies the second AC power via the output unit 4. The magnitude of the voltage output by the power conversion unit 3 is the same as the rated voltage of the commercial power source 200. As shown in FIG. 2, the power conversion device 100 has a second live electric circuit C21 and a second neutral electric circuit C22 that are respectively connected to a pair of AC output terminals of the power conversion unit 3. The power storage unit 2 and the power conversion unit 3 of this embodiment constitute a stand-alone storage battery. The stand-alone storage battery is a storage device that outputs AC power that is not interconnected with the commercial power source 200 as the second AC power. The power storage unit 2 is preferably a secondary battery that can be repeatedly used by charging and discharging, such as a lithium ion battery or a solid-state battery.

[0015] The output unit 4 is electrically connected to a load. As shown in Figs. 1 and 2, the output unit 4 of the embodiment is electrically connected to an electric device 300 which is a load. The electric device 300 is, for example, an air conditioner or a television receiver.

[0016] The earth leakage current detection unit 6 detects an earth leakage current due to the second AC power. In this embodiment, the earth leakage current detection unit 6 is provided between the power conversion unit 3 and the output switching unit 5. In addition, the earth leakage current detection unit 6 in this embodiment is a zero-phase current transformer, and as shown in Fig. 2, the earth leakage current detection unit 6 is provided so as to penetrate the second live electric circuit C21 and the second neutral electric circuit C22 to which the second AC power output from the power conversion unit 3 is transmitted. The zero-phase current transformer measures the current difference between the second live electric circuit C21 and the second neutral electric circuit C22, and detects an earth leakage current due to the second AC power.

[0017] The control unit 7 includes a leakage current processing unit 71. The leakage current processing unit 71 detects leakage current based on the result of the leakage current detection unit 6. When the leakage current processing unit 71 detects leakage current, it outputs an operation stop signal A4 to the power conversion unit 3. As a result, the power conversion unit 3 stops the power conversion from DC power to the second AC power. As an example, when the output switching unit 5 breaks down, the second AC power may be transmitted to the input unit 1. In this case, when the person operating the power conversion device 100 touches the live input terminal 11, it is considered that the second AC power may leak.

[0018] The output switching unit 5 switchably transmits the first AC power transmitted from the input unit 1 and the second AC power transmitted from the power conversion unit 3 to the output unit 4. The output switching unit 5 includes a first relay unit 51 provided between the input unit 1 and the output unit 4, and a second relay unit 52 provided between the power conversion unit 3 and the output unit 4. The first relay unit 51 establishes and breaks the electrical connection between the input unit 1 and the output unit 4, and the second relay unit 52 establishes and breaks the electrical connection between the power conversion unit 3 and the output unit 4.

[0019] The power conversion device 100 further includes a third live electric circuit C31 and a third neutral electric circuit C32 as a pair of electric circuits electrically connected to the output unit 4. The third live electric circuit C31 is electrically connected or disconnected from the first live electric circuit C11 via the first relay unit 51, and is electrically connected or disconnected from the second live electric circuit C21 via the second relay unit 52. The third neutral electric circuit C32 is electrically connected or disconnected from the first neutral electric circuit C12 via the first relay unit 51, and is electrically connected or disconnected from the second neutral electric circuit C22 via the second relay unit 52.

[0020] 1, the first relay unit 51 includes a plurality of first contact parts 511, and the second relay unit 52 includes a plurality of second contact parts 521. The plurality of first contact parts 511 are connected in series between the input unit 1 and the output unit 4, and the plurality of second contact parts 521 are connected in series between the power conversion unit 3 and the output unit 4.

[0021] As shown in Fig. 2, the power conversion device 100 of this embodiment includes two first contacts 511a and 511b as the multiple first contacts 511. In the first relay unit 51, the two first contacts 511a and 511b are connected in series via a pair of internal electric circuits. That is, the first contact 511a conducts or cuts off the electrical connection between the first live electric circuit C11 and the first neutral electric circuit C12 and the pair of internal electric circuits of the first relay unit 51. The first contact 511b conducts or cuts off the electrical connection between the third live electric circuit C31 and the third neutral electric circuit C32 and the pair of internal electric circuits of the second relay unit 52.

[0022] 2, the power conversion device 100 includes two second contacts 521a and 521b as the plurality of second contacts 521. In the second relay unit 52, the two second contacts 521a and 521b are connected in series via a pair of internal electric circuits. That is, the second contact 521a establishes or breaks electrical connection between the second live electric circuit C21 and the second neutral electric circuit C22 and the pair of internal electric circuits of the second relay unit 52. The second contact 521b establishes or breaks electrical connection between the third live electric circuit C31 and the third neutral electric circuit C32 and the pair of internal electric circuits of the second relay unit 52.

[0023] The output switching unit 5 includes a voltage detection unit 53 that detects at least one internal voltage of the output switching unit 5. The control unit 7 controls the output switching unit 5 based on the at least one internal voltage detected by the voltage detection unit 53.

[0024] Specifically, the voltage detection unit 53 includes a first voltage detection unit 531 and a second voltage detection unit 532. The first voltage detection unit 531 detects a first internal voltage Vs1, which is a voltage of the internal electrical circuit between a pair of first contact parts 511a and 511b, as an internal voltage. Similarly, the second voltage detection unit 532 detects a second internal voltage Vs2, which is a voltage of the internal electrical circuit between a pair of second contact parts 521a and 521b, as an internal voltage. As shown in FIG. 2, the first voltage detection unit 531 of this embodiment is provided between the first contact part 511a and the first contact part 511b. The second voltage detection unit 532 of this embodiment is provided between the second contact part 521a and the second contact part 521b.

[0025] The first voltage detection unit 531 outputs the detection result of the first internal voltage Vs1 as a first detection signal A21. Specifically, if the first internal voltage Vs1 is equal to or higher than the threshold Vt1, the first voltage detection unit 531 sets the first detection signal A21 to an L level, and if the first internal voltage Vs1 is lower than the threshold Vt1, the first voltage detection unit 531 sets the first detection signal A21 to an H level.

[0026] The second voltage detection unit 532 outputs the detection result of the second internal voltage Vs2 as a second detection signal A22. Specifically, if the second internal voltage Vs2 is equal to or higher than the threshold Vt1, the second voltage detection unit 532 sets the second detection signal A22 to an L level, and if the second internal voltage Vs2 is lower than the threshold Vt2, the second voltage detection unit 532 sets the second detection signal A22 to an H level.

[0027] The control unit 7 drives the first relay unit 51 based on the second internal voltage Vs2. This is for the purpose of preventing the first AC power and the second AC power from being simultaneously transmitted to the third live electric circuit C31 and the third neutral electric circuit C32 when the first contact unit 511 is unintentionally brought into a conductive state due to welding or the like. Similarly, the control unit 7 drives the second relay unit 52 based on the first internal voltage Vs1. This is for the purpose of preventing the first AC power and the second AC power from being simultaneously transmitted to the third live electric circuit C31 and the third neutral electric circuit C32 when the second contact unit 521 is unintentionally brought into a conductive state due to welding or the like.

[0028] More specifically, the control unit 7 includes a signal generating unit 72, a first drive control unit 73, and a second drive control unit 74. The signal generating unit 72 generates and outputs a signal A11 that controls the first relay unit 51 and a signal A12 that controls the second relay unit 52.

[0029] The first drive control unit 73 drives the first contacts 511a and 511b based on the second detection signal A22 and the first control signal A11. The second drive control unit 74 drives the second contacts 521a and 521b based on the first detection signal A21 and the second control signal A12.

[0030] In this embodiment, the first drive control unit 73 is a first AND gate to which the second detection signal A22 and the first control signal A11 are input, and the second drive control unit 74 is a second AND gate to which the first detection signal A21 and the second control signal A12 are input.

[0031] When the second detection signal A22 and the first control signal A11 input to the first drive control unit 73 are all at H level (e.g., 5V), the first drive control unit 73 outputs an H-level first drive signal A31. On the other hand, when at least one of the second detection signal A22 and the first control signal A11 input to the first drive control unit 73 is at L level (e.g., 0V), the first drive control unit 73 outputs an L-level first drive signal A31.

[0032] Similarly, when the first detection signal A21 and the second control signal A12 input to the second drive control unit 74 are all at H level (e.g., 5V), the second drive control unit 74 outputs the second drive signal A32 at H level. On the other hand, when at least one of the first detection signal A21 and the second control signal A12 input to the second drive control unit 74 is at L level (e.g., 0V), the second drive control unit 74 outputs the second drive signal A32 at L level.

[0033] The control unit 7 further includes an abnormality determination unit 75. The abnormality determination unit 75 receives the first detection signal A21 from the first voltage detection unit 531 and the second control signal A12 from the signal generation unit 72. When the second control signal A12 is at H level and the state where the first detection signal A21 is at L level continues for a certain period of time, the abnormality determination unit 75 determines that an abnormality has occurred in which at least one of the first contacts 511a and 511b does not operate according to the first drive signal A31 due to a cause such as welding. Thereafter, the abnormality determination unit 75 outputs an abnormality stop signal A5 to the power conversion unit 3 to stop the operation of the power conversion unit 3. The power conversion unit 3 receives the abnormality stop signal A5 and stops the power conversion from the DC power stored in the power storage unit 2 to the second AC power.

[0034] Similarly, the abnormality determination unit 75 receives the second detection signal A22 from the second voltage detection unit 532 and the first control signal A11 from the signal generation unit 72. When the first control signal A11 is at H level and the second detection signal A22 is at L level for a certain period of time, the abnormality determination unit 75 determines that an abnormality has occurred in which at least one of the second contacts 521a and 521b does not operate according to the second drive signal A32 due to welding or the like. Thereafter, the abnormality determination unit 75 outputs an abnormality stop signal A5 to the power conversion unit 3 to stop the operation of the power conversion unit 3. The power conversion unit 3 receives the abnormality stop signal A5 and stops the power conversion from the DC power stored in the power storage unit 2 to the second AC power.

[0035] (3) Operation (3.1) From leakage current detection to shutdown of power conversion unit 3 Hereinafter, the operation from the detection of a ground fault to the stopping of the power conversion unit 3 in this embodiment will be described with reference to FIG.

[0036] First, the leakage processing unit 71 determines whether or not a leakage current has occurred in the second AC power (S11) based on the leakage current data detected by the leakage current detection unit 6. If the leakage processing unit 71 determines that a leakage current has not occurred (S11: NO), the leakage processing unit 71 again determines whether or not a leakage current has occurred in the second AC power after a predetermined time has elapsed (S11).

[0037] When the leakage processing unit 71 determines that a leakage current is occurring in the second AC power (S11: YES), the leakage processing unit 71 outputs an operation stop signal A4 to the power conversion unit 3 (S12).

[0038] The power conversion unit 3 receives the operation stop signal A4 and stops the power conversion from the DC power stored in the power storage unit 2 to the second AC power.

[0039] (3.2) Output switching from the first AC power to the second AC power Hereinafter, the operation of switching the output from the first AC power to the second AC power in this embodiment will be described with reference to Fig. 4. Moreover, the operation of turning off a signal means outputting a voltage of an L level (e.g., 0V) as a signal, and the operation of turning on a signal means outputting a voltage of an H level (e.g., 5V) as a signal.

[0040] First, the first control signal A11 is on, the second control signal A12 is off, the first detection signal A21 is off, and the second detection signal A22 is on. At this time, the first contact portion 511a and the first contact portion 511b are conductive, the second contact portion 521a and the second contact portion 521b are cut off, and the first AC power is output from the output portion 4 to the electric device 300 (S21).

[0041] Then, the signal generating unit 72 turns off the first control signal A11 (S22). As a result, the first drive control unit 73 turns off the first drive signal A31, and the first contact unit 511a and the first contact unit 511b are cut off. When a predetermined delay time has elapsed since the signal generating unit 72 turned off the first control signal A11, the signal generating unit 72 turns on the second control signal A12 (S23).

[0042] Next, the first voltage detection unit 531 detects the first internal voltage Vs1 of the first relay unit 51, and determines whether the first internal voltage Vs1 of the first relay unit 51 is less than the threshold voltage Vt1 (S24). The threshold voltage Vt1 is set to a value lower than the first internal voltage Vs1 of the first relay unit 51 detected when at least one of the first contact portion 511a and the first contact portion 511b is conductive, and higher than 0V.

[0043] If the first internal voltage Vs1 of the first relay unit 51 is less than the threshold Vt1 (S24: YES), the first voltage detection unit 531 turns on the first detection signal A21 and outputs the turned-on first detection signal A21 to the second drive control unit 74 (S25). If the first internal voltage Vs1 of the first relay unit 51 is equal to or greater than the threshold Vt1 (S24: NO), the first voltage detection unit 531 turns off the first detection signal A21 and outputs the turned-off first detection signal A21 to the second drive control unit 74 (S26).

[0044] The second drive control section 74 determines whether or not both of the input second control signal A12 and the input first detection signal A21 are on (S27).

[0045] When both the second control signal A12 and the first detection signal A21 are on (S27: YES), the second drive control unit 74 turns on the second drive signal A32 and outputs the turned-on second drive signal A32 to the second contact unit 521a and the second contact unit 521b. After that, the second contact unit 521a and the second contact unit 521b are all conductive, and the second AC power is output from the output unit 4 to the electric device 300 (S2A).

[0046] On the other hand, when the second control signal A12 is on and the first detection signal A21 is off (S27: NO), the second drive control unit 74 turns off the second drive signal A32 and outputs the turned-off second drive signal A32 to the second contact unit 521a and the second contact unit 521b (S29). When the second control signal A12 is on and the first detection signal A21 is off for a certain period of time, the abnormality determination unit 75 determines that an abnormality has occurred in which at least one of the first contact units 511a and 511b does not operate according to the first drive signal A31 due to welding or the like, and outputs an abnormality stop signal A5 to the power conversion unit 3 to stop the operation of the power conversion unit 3. The power conversion unit 3 receives the abnormality stop signal A5 and stops the power conversion from the DC power stored in the power storage unit 2 to the second AC power.

[0047] (3.3) Output switching from the second AC power to the first AC power Hereinafter, the operation of switching the output from the second AC power to the first AC power in this embodiment will be described with reference to Fig. 5. Moreover, the operation of turning off a signal means outputting a voltage of an L level (e.g., 0V) as a signal, and the operation of turning on a signal means outputting a voltage of an H level (e.g., 5V) as a signal.

[0048] First, the first control signal A11 is OFF, the second control signal A12 is ON, the first detection signal A21 is ON, and the second detection signal A22 is OFF. At this time, the first contact portion 511a and the first contact portion 511b are cut off, the second contact portion 521a and the second contact portion 521b are conductive, and the second AC power is output from the output portion 4 to the electric device 300 (S31).

[0049] Then, the signal generating unit 72 turns off the second control signal A12 (S32). As a result, the second drive control unit 74 turns off the second drive signal A32, and the second contact parts 521a and 521b are cut off. When a predetermined delay time has elapsed since the signal generating unit 72 turned off the second control signal A12, the signal generating unit 72 turns on the first control signal A11 (S33).

[0050] Next, the second voltage detection unit 532 detects the second internal voltage Vs2 of the second relay unit 52, and determines whether the second internal voltage Vs2 of the second relay unit 52 is less than the threshold voltage Vt2 (S34). The threshold voltage Vt2 is set to a value lower than the second internal voltage Vs2 of the second relay unit 52 detected when at least one of the second contact portion 521a and the second contact portion 521b is conductive, and higher than 0V.

[0051] If the second internal voltage Vs2 of the second relay unit 52 is less than the threshold Vt2 (S34: YES), the second voltage detection unit 532 turns on the second detection signal A22 and outputs the turned-on second detection signal A22 to the first drive control unit 73 (S35). If the second internal voltage Vs2 of the second relay unit 52 is equal to or greater than the threshold Vt2 (S34: NO), the second voltage detection unit 532 turns off the second detection signal A22 and outputs the turned-off second detection signal A22 to the first drive control unit 73 (S36).

[0052] The first drive control unit 73 determines whether or not both of the input first control signal A11 and second detection signal A22 are on (S37).

[0053] When both the first control signal A11 and the second detection signal A22 are on (S37: YES), the first drive control unit 73 turns on the first drive signal A31 and outputs the turned-on first drive signal A31 to the first contact unit 511a and the first contact unit 511b. After that, the first contact unit 511a and the first contact unit 511b are all conductive, and the first AC power is output from the output unit 4 to the electric device 300 (S3A).

[0054] On the other hand, when the first control signal A11 is on and the second detection signal A22 is off (S37: NO), the first drive control unit 73 turns off the first drive signal A31 and outputs the turned-off first drive signal A31 to the first contact unit 511a and the first contact unit 511b (S39). When the first control signal A11 is on and the second detection signal A22 is off for a certain period of time, the abnormality determination unit 75 determines that an abnormality has occurred in which at least one of the second contact units 521a and 521b does not operate according to the second drive signal A32 due to welding or the like, and outputs an abnormality stop signal A5 to the power conversion unit 3 to stop the operation of the power conversion unit 3. The power conversion unit 3 receives the abnormality stop signal A5 and stops the power conversion from the DC power stored in the power storage unit 2 to the second AC power.

[0055] (4) Variations The above-described embodiment is merely one of various embodiments of the present disclosure. The above-described embodiment can be modified in various ways depending on the design and the like as long as the object of the present disclosure can be achieved.

[0056] In the above-described embodiment, the leakage current detection unit 6 may be provided at a position where the leakage current of the second AC power can be detected, and may be provided between the input unit 1 and the output switching unit 5. Also, it may be provided between the output switching unit 5 and the output unit 4.

[0057] As shown in FIG. 6 , the first relay unit 51 in one embodiment may include a first weld detection unit 512 that detects welding of at least one first contact portion 511, and the second relay unit 52 in one embodiment may include a second weld detection unit 522 that detects welding of at least one second contact portion 521.

[0058] The control unit 7 preferably includes a computer system. In the computer system, a processor such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit) reads and executes a program stored in a memory, thereby realizing some or all of the functions of the control unit 7. The computer system includes a processor that operates according to a program as a main hardware configuration. The type of processor is not important as long as it can realize the function by executing the program. The processor is composed of one or more electronic circuits including a semiconductor integrated circuit (IC) or an LSI (Large Scale Integration). Although IC and LSI are referred to here, the name may change depending on the degree of integration, and may be called a system LSI, VLSI (Very Large Scale Integration), or ULSI (Ultra Large Scale Integration). A field programmable gate array (FPGA), which is programmed after the LSI is manufactured, or a reconfigurable logic device that can reconfigure the connection relationship inside the LSI or set up the circuit partition inside the LSI, can also be used for the same purpose. Multiple electronic circuits may be integrated into one chip or provided on multiple chips. The multiple chips may be integrated into one device, or may be provided in multiple devices.

[0059] (5) Summary As described above, the power conversion device (100) according to the first aspect includes an input unit (1), a power storage unit (2), a power conversion unit (3), an output unit (4), an output switching unit (5), a leakage current detection unit (6), and a control unit (7). The input unit (1) receives a first AC power from a commercial power source (200). The power storage unit (2) stores DC power. The power conversion unit (3) converts the DC power into a second AC power. The output unit (4) is electrically connected to a load. The output switching unit (5) transmits the first AC power and the second AC power to the output unit (4) in a switchable manner. The leakage current detection unit (6) detects a leakage current of the second AC power. The control unit (7) detects leakage based on a result of the leakage current detection unit (6), and stops the power conversion unit (3) when a leakage is detected.

[0060] According to this embodiment, there is an advantage that a leakage current in the second AC power can be confirmed.

[0061] In the power converter (100) according to the second aspect, in the first aspect, the leakage current detector (6) is provided between the power converter (3) and the output switch (5).

[0062] According to this embodiment, there is an advantage that it is possible to check for leakage of the second AC power in the electric path that transmits the second AC power.

[0063] In the power conversion device (100) according to the third aspect, in the first aspect, the leakage current detection section (6) is provided between the input section (1) and the output switching section (5).

[0064] According to this embodiment, there is an advantage that it is possible to check for leakage of the second AC power in the electric circuit on the input portion (1) side.

[0065] In the power conversion device (100) according to the fourth aspect, in the first aspect, the leakage current detection section (6) is provided between the output switching section (5) and the output section (4).

[0066] According to this embodiment, there is an advantage that it is possible to check for leakage of the second AC power in the electric circuit on the output portion (4) side.

[0067] In the power conversion device (100) according to the fifth aspect, in any of the first to fourth aspects, the output switching section (5) includes a first relay unit (51) provided between the input section (1) and the output section (4) and a second relay unit (52) provided between the power conversion section (3) and the output section (4). The first relay unit (51) establishes and breaks electrical connection between the input section (1) and the output section (4). The second relay unit (52) establishes and breaks electrical connection between the power conversion section (3) and the output section (4).

[0068] This embodiment has the advantage that it is possible to control both the electrical connection between the input unit (1) and the output unit (4) and the electrical connection between the power conversion unit (3) and the output unit (4).

[0069] In the power conversion device (100) according to the sixth aspect, in the fifth aspect, the first relay unit (51) includes a plurality of first contact portions (511), and the second relay unit (52) includes a plurality of second contact portions (521). The plurality of first contact portions (511) are connected in series between the input portion (1) and the output portion (4). The plurality of second contact portions (521) are connected in series between the power conversion portion (3) and the output portion (4).

[0070] According to this embodiment, even if one or more of the first contact parts (511) are welded, the remaining unwelded first contact parts (511) can control the electrical connection between the input part (1) and the output part (4). Similarly, even if one or more of the second contact parts (521) are welded, the remaining unwelded second contact parts (521) can control the electrical connection between the power conversion part (3) and the output part (4).

[0071] The power conversion device (100) according to the seventh aspect is the same as the sixth aspect, and further includes a voltage detection unit (53) that detects an internal voltage of at least one output switching unit (5). The control unit (7) controls the output switching unit (5) based on the at least one internal voltage.

[0072] This embodiment has the advantage that it is possible to check whether the contacts of the output switching unit (5) are welded or not.

[0073] In the power conversion device (100) according to the eighth aspect, in the seventh aspect, the voltage detection unit includes a first voltage detection unit (531) that detects, as an internal voltage, a first internal voltage (Vs1) which is a voltage of an electric path between a pair of first contact units (511) among the plurality of first contact units (511), and a second voltage detection unit (532) that detects, as an internal voltage, a second internal voltage (Vs2) which is a voltage of an electric path between a pair of second contact units (521) among the plurality of second contact units (521). The control unit (7) controls the first relay unit (51) based on the second internal voltage (Vs2) and controls the second relay unit (52) based on the first internal voltage (Vs1).

[0074] According to this embodiment, there is an advantage that it is possible to check whether or not the contacts of the first relay unit (51) and the second relay unit (52) are welded, for each of the first relay unit (51) and the second relay unit (52).

[0075] In the power conversion device (100) according to the ninth aspect, in the eighth aspect, the control unit (7) includes a signal generating unit (72), a first drive control unit (73), and a second drive control unit (74). The signal generating unit (72) outputs a first control signal (A11) for controlling the first relay unit (51) and a second control signal (A12) for controlling the second relay unit (52). The first voltage detecting unit (531) outputs a detection result of the first internal voltage (Vs1) as a first detection signal (A21), and the second voltage detecting unit (532) outputs a detection result of the second internal voltage (Vs2) as a second detection signal (A22). The first drive control section (73) drives the multiple first contact sections (511) based on the second detection signal (A22) and the first control signal (A11), and the second drive control section (74) drives the multiple second contact sections (521) based on the first detection signal (A21) and the second control signal (A12).

[0076] This aspect has the advantage that, when the first contact portion (511) is unintentionally brought into a conductive state due to welding or the like, the first AC power and the second AC power can be prevented from being transmitted simultaneously to the output portion (4). Similarly, it has the advantage that, when the second contact portion (521) is unintentionally brought into a conductive state due to welding or the like, the first AC power and the second AC power can be prevented from being transmitted simultaneously to the output portion (4).

[0077] In the power conversion device (100) according to the tenth aspect, in the ninth aspect, the first drive control unit (73) is a first AND gate to which the second detection signal (A22) and the first control signal (A11) are input, and the second drive control unit (74) is a second AND gate to which the first detection signal (A21) and the second control signal (A12) are input.

[0078] This embodiment has the advantage that the configuration of the first drive control section (73) and the second drive control section (74) can be simplified.

[0079] In the power conversion device (100) according to the eleventh aspect, in any of the sixth to tenth aspects, the first relay unit (51) includes a first weld detection unit (512) that detects welding of at least one first contact portion (511), and the second relay unit (52) includes a second weld detection unit (522) that detects welding of at least one second contact portion (521).

[0080] This embodiment has the advantage that welding of the first contact portion (511) and the second contact portion (521) can be detected.

[0081] In the power conversion device (100) according to the twelfth aspect, in any one of the first to eleventh aspects, the electricity storage unit (2) and the power conversion unit (3) are formed of stand-alone storage batteries.

[0082] According to this aspect, in a configuration including a stand-alone storage battery, there is an advantage that it is possible to check for leakage of the second AC power. [Explanation of symbols]

[0083] 100 Power conversion device 200 Commercial power supply 1 Input section 2. Power storage unit 3 Power conversion section 4 Output section 5 Output switching section 51 First Relay Unit 511 First contact part 512 First welding detection unit 52 Second Relay Unit 521 Second contact part 522 Second welding detection unit 53 Voltage detection section 531 First voltage detection unit 532 Second voltage detection unit 6. Leakage current detection section 7 Control section 72 Signal Generator 73 First drive control section 74 Second drive control section A11 First control signal A12 Second control signal A21 First detection signal A22 Second detection signal Vs1 First internal voltage Vs2 Second internal voltage

Claims

1. an input unit to which a first AC power is input from a commercial power source; a power storage unit that stores DC power; a power conversion unit that converts the DC power into a second AC power; an output section to which a load is electrically connected; an output switching unit that switchably transmits the first AC power and the second AC power to the output unit; a leakage current detection unit that detects a leakage current of the second AC power; a control unit that detects leakage current based on a result of the leakage current detection unit and stops the power conversion unit when the leakage current is detected; a voltage detection unit that detects an internal voltage of at least one of the output switching units, the output switching unit includes a first relay unit provided between the input unit and the output unit, and a second relay unit provided between the power conversion unit and the output unit, the first relay unit establishes and interrupts an electrical connection between the input section and the output section; The second relay unit establishes and interrupts an electrical connection between the power conversion unit and the output unit, the first relay unit includes a plurality of first contact portions; the second relay unit includes a plurality of second contact portions; the first contact portions are connected in series between the input portion and the output portion, the second contact portions are connected in series between the power conversion portion and the output portion, the voltage detection unit includes a first voltage detection unit that detects, as the internal voltage, a first internal voltage that is a voltage of an electric path between a pair of first contact portions among the plurality of first contact portions, and a second voltage detection unit that detects, as the internal voltage, a second internal voltage that is a voltage of an electric path between a pair of second contact portions among the plurality of second contact portions, the control unit includes a signal generating unit, a first drive control unit, and a second drive control unit; The signal generating unit outputs a first control signal for controlling the first relay unit and a second control signal for controlling the second relay unit; the first voltage detection unit outputs a detection result of the first internal voltage as a first detection signal; the second voltage detection unit outputs a detection result of the second internal voltage as a second detection signal; the first drive control unit drives the first contact units based on the second detection signal and the first control signal; The second drive control unit drives the second contact units based on the first detection signal and the second control signal. Power conversion equipment.

2. The leakage current detection unit is provided between the power conversion unit and the output switching unit. The power conversion device according to claim 1 .

3. The leakage current detection unit is provided between the input unit and the output switching unit. The power conversion device according to claim 1 .

4. The leakage current detection unit is provided between the output switching unit and the output unit. The power conversion device according to claim 1 .

5. The first drive control unit is a first AND gate to which the second detection signal and the first control signal are input, the second drive control unit is a second AND gate to which the first detection signal and the second control signal are input; The power conversion device according to any one of claims 1 to 4.

6. The first relay unit includes a first welding detection unit that detects welding of at least one of the first contact portions, The second relay unit includes a second welding detection unit that detects welding of at least one of the second contact portions. The power conversion device according to any one of claims 1 to 5.

7. The power storage unit and the power conversion unit are composed of stand-alone storage batteries. The power conversion device according to any one of claims 1 to 6.

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