Power conversion system and measuring device

Abstract

To provide a power conversion system and a measurement device capable of expanding a measurement range.SOLUTION: A power conversion system includes a power conversion unit, a measurement unit (a measurement unit 1), and a terminal unit 21. The power conversion unit performs power conversion between DC power and AC power. The measurement unit 1 measures at least one of DC power and AC power. The terminal unit 21 electrically connects the power conversion unit and the measurement unit 1.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure generally relates to a power conversion system and a measurement device, and more particularly to a power conversion system that performs power conversion between DC power and AC power, and a measurement device used in the power conversion system. [Background technology]

[0002] Patent Document 1 describes a grid-connected system (power conversion system). The grid-connected system described in Patent Document 1 includes a power conversion unit. The power conversion unit converts DC power supplied from a distributed power source into AC power. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-259170 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a power conversion system such as that described in Patent Document 1, power that cannot be measured by a smart meter is not subject to billing, and therefore it is desirable to expand the measurement range.

[0005] An object of the present disclosure is to provide a power conversion system and a measurement device that are capable of expanding the measurement range. [Means for solving the problem]

[0006] A power conversion system according to an aspect of the present disclosure includes a power conversion unit, a measurement unit, and a terminal unit. The power conversion unit performs power conversion between DC power and AC power. The measurement unit measures at least one of the DC power and the AC power. The terminal unit electrically connects the power conversion unit and the measurement unit. The power conversion unit and the measurement unit are integrated. The power conversion system further includes a plurality of inspection terminals and an inspection relay. The plurality of inspection terminals electrically connect an inspection device that inspects the measurement unit to the measurement unit. The inspection relay is switched to a first state in which the power conversion unit and the measurement unit are connected, or a second state in which the measurement unit is disconnected from the power conversion unit. The inspection relay is switched to the second state when the measurement unit is inspected by the inspection device.

[0007] A measurement device according to an aspect of the present disclosure functions as the measurement unit of the power conversion system, and is electrically connected to the power conversion unit by the terminal unit. Effect of the Invention

[0008] According to a power conversion system and a measurement device according to an aspect of the present disclosure, it is possible to expand the measurement range. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic configuration diagram showing an application example of a power conversion system according to an embodiment. [Diagram 2] FIG. 2 is a schematic circuit diagram showing a main part of the power conversion system. [Diagram 3] FIG. 3 is a schematic circuit diagram showing the above power conversion system. [Figure 4] Fig. 4A is a schematic circuit diagram showing a state where a measuring unit is connected to the power conversion system of the above embodiment, and Fig. 4B is a schematic circuit diagram showing a state where a measuring unit is not connected to the power conversion system of the above embodiment. [Diagram 5] 5A to 5C are schematic diagrams showing a sealing structure of the measurement unit. [Figure 6] FIG. 6 is a schematic circuit diagram showing a main part of a power conversion system according to a first modification of the embodiment. [Figure 7] Fig. 7A is a schematic block diagram showing a measurement unit used in a power conversion system according to a second modification of the embodiment. Fig. 7B is a schematic block diagram showing a measurement unit used in a power conversion system according to a third modification of the embodiment. [Figure 8] FIG. 8 is a schematic circuit diagram showing a power conversion system according to a fourth modification of the embodiment. [Figure 9] FIG. 9 is a schematic circuit diagram showing a main part of a power conversion system according to a fifth modification of the embodiment. [Figure 10]FIG. 10 is a schematic circuit diagram showing a method for inspecting a measuring unit used in the power conversion system. [Figure 11] FIG. 11 is a schematic configuration diagram showing an application example of a power conversion system according to the sixth modification of the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] (Embodiment) Hereinafter, the power conversion system and the measurement device according to this embodiment will be described with reference to FIGS.

[0011] However, the embodiment and modified examples described below are merely examples of the present disclosure, and the present disclosure is not limited to the following embodiment and modified examples. Various modifications other than the following embodiment and modified examples are possible according to the design, etc., as long as they do not deviate from the technical idea of ​​the present disclosure.

[0012] In addition, all of the drawings described in the following embodiments are schematic drawings, and the ratios of size and thickness of each component in each drawing do not necessarily reflect the actual dimensional ratios.

[0013] (1) Overview First, an overview of a power conversion system 100 and a measurement device 1 according to the present embodiment will be described with reference to FIGS. 1 to 3. FIG.

[0014] The power conversion system 100 according to the present embodiment is a system that performs power conversion between DC power and AC power. More specifically, the power conversion system 100 is a system that performs power conversion in at least one of a first direction in which DC power is converted into AC power and a second direction in which AC power is converted into DC power. As an example in the present embodiment, the power conversion system 100 is a system that is electrically connected to a DC power source 400 (see FIG. 1) such as a solar power generation facility, converts DC power output from the DC power source 400 into AC power, and outputs the AC power, and includes a power conditioner. That is, the power conversion system 100 is a unidirectional power conversion system that performs power conversion only in the first direction.

[0015] 2 and 3, a measurement device (measurement unit) 1 according to this embodiment is a device electrically connected to a power conversion system 100 to measure the power of the power conversion system 100. In this embodiment, as an example, the measurement device 1 is electrically connected to a path on the AC side of the power conversion system 100 to measure AC power. The measurement device 1 is configured to be detachable from the power conversion system 100. The power conversion system 100 includes a terminal section 21 (see FIG. 4A) that electrically connects the power conversion section 3 and the measurement device (measurement section) 1.

[0016] As described above, the power conversion system 100 according to this embodiment includes a power conversion unit 3, a measurement unit (measurement device) 1, and a terminal unit 21. The power conversion unit 3 performs power conversion between DC power and AC power. The measurement unit 1 measures at least one of the DC power and the AC power. The terminal unit 21 electrically connects the power conversion unit 3 and the measurement unit 1. Furthermore, the measurement device 1 according to this embodiment functions as the measurement unit 1 of the power conversion system 100 described above. The measurement device 1 is electrically connected to the power conversion unit 3 by the terminal unit 21.

[0017] In the power conversion system 100 and the measurement device 1 according to the present embodiment, as described above, the measurement device (measurement unit) 1 is electrically connected to the power conversion unit 3 of the power conversion system 100 by the terminal unit 21. This allows the measurement device 1 to measure at least one of DC power, which is the power on the DC side of the power conversion unit 3, and AC power, which is the power on the AC side of the power conversion unit 3. Therefore, it is possible to expand the measurement range compared to the conventional configuration in which AC power is measured by a smart meter. Also, in the power conversion system 100 and the measurement device 1 according to the present embodiment, as described above, the measurement device 1 is electrically connected to the power conversion unit 3 by the terminal unit 21. Therefore, the measurement device 1 can be attached to and detached from the power conversion system 100.

[0018] (2) Details Next, the power conversion system 100 and the measurement device 1 according to this embodiment will be described in detail with reference to FIGS. 1 to 4B.

[0019] (2.1) Premise In this embodiment, as described above, a case will be described in which the power conversion system 100 is a unidirectional power conversion system that converts DC power into AC power. In this embodiment, the measurement device 1 is installed in a facility F1 (see FIG. 1) together with the power conversion system 100. The facility F1 in which the measurement device 1 and the power conversion system 100 are installed is, for example, a residential facility such as a detached house or an apartment building, or a non-residential facility such as an office, a store, a school, a factory, a hospital, or a nursing home. In this embodiment, as an example, the facility F1 in which the measurement device 1 and the power conversion system 100 are installed is a detached house.

[0020] (2.2) Power Supply System First, a configuration of a power supply system 1000 including a power conversion system 100 according to the present embodiment will be described with reference to Fig. 1. As shown in Fig. 1, the power supply system 1000 includes the power conversion system 100, a distribution board 200, a smart meter 300, and a DC power supply 400. In the present embodiment, the power conversion system 100, the distribution board 200, the smart meter 300, and the DC power supply 400 are included as components of the power supply system 1000. However, it is not essential that the power supply system 1000 includes all of the power conversion system 100, the distribution board 200, the smart meter 300, and the DC power supply 400 as components.

[0021] In this embodiment, as an example, the DC power supply 400 is a solar power generation facility that outputs power according to the amount of solar radiation as generated power.

[0022] 1, the power conversion system 100 converts DC power P1 output from a DC power source 400 into AC power P2. The power conversion system 100 outputs AC power P21, which is a part of the converted AC power P2, to a distribution board 200 and supplies the AC power P21 to a load device via the distribution board 200. The "load device" referred to here is an apparatus (including an appliance, a facility, and a system) that is electrically connected to the distribution board 200 and used in the facility F1, such as a lighting fixture, an air conditioner, and a television receiver. The distribution board 200 is electrically connected to a smart meter 300, and the load device is supplied with AC power P3 from the smart meter 300 or AC power P21 from the DC power source 400 via the power conversion system 100.

[0023] Here, the power conversion system 100 is configured to be capable of being interconnected to a grid. In the present disclosure, "grid-interconnected" refers to a state in which a DC power source 400 consisting of a power generation facility such as a solar power generation facility is electrically connected to a commercial power system, and power can be supplied to a load device from both the DC power source 400 and the commercial power system. In other words, at least the power conversion system 100 supplies the generated power (output power) of the DC power source 400 consisting of a solar power generation facility to the load device, in addition to or instead of power from the commercial power system.

[0024] Particularly in this embodiment, the power conversion system 100 is capable of converting the power generated by the DC power source 400 into AC power and supplying the converted AC power to the commercial power system while being electrically connected to the commercial power system. In other words, in this embodiment, a system interconnection type capable of "reverse power flow" in which the power generated by the DC power source 400 is output to the commercial power system is assumed. Therefore, for example, when the power generated by the DC power source 400 is surplus to the power consumed by the load device, the power conversion system 100 is capable of "reverse power flow" in which this surplus power is output to the commercial power system. In the present disclosure, "surplus" refers to the difference between the power generated by the DC power source 400 and the power consumed by the load device in a situation in which the power generated by the DC power source 400 exceeds the power consumed by the load device and all of the power generated by the DC power source 400 cannot be consumed by the load device. The power conversion system 100 outputs AC power P22, which is surplus power excluding the AC power P21 output to the distribution board 200 from the converted AC power P2, to the commercial power system.

[0025] (2.3) Power Conversion System Next, the configuration of the power conversion system 100 according to this embodiment will be described with reference to FIGS. 2 to 4A.

[0026] As shown in FIG. 2, the power conversion system 100 according to the present embodiment includes an inverter 3 (hereinafter, also referred to as "power conversion unit 3") as a power conversion unit, a measurement unit 1 (hereinafter, also referred to as "measurement unit 1 or measurement device 1") as a measurement unit (measurement device), and a terminal unit 21 (see FIG. 4A). As shown in FIG. 3, the power conversion system 100 according to the present embodiment further includes an input capacitor C0, an output capacitor C1, a rectifier element D1, a DC / DC converter 2, a noise filter 4, a parallel-off relay 5, and an independent relay 6. The power conversion system 100 further includes an earth leakage breaker 7, a first current measurement unit 8 (see FIG. 4A), a voltage measurement unit 9, and a control unit 10. The measurement unit 1, the inverter 3, and the terminal unit 21 are all housed in a single first housing (housing) 101. The input capacitor C0, the output capacitor C1, the rectifier element D1, the DC / DC converter 2, the noise filter 4, the parallel-off relay 5, and the independent relay 6 are also housed in the first housing 101. The earth leakage breaker 7, the first current measuring unit 8, the voltage measuring unit 9, and the control unit 10 are also housed in the first housing 101.

[0027] 3, a DC power supply 400 is connected to the power conversion system 100. In this embodiment, the DC power supply 400 is a photovoltaic power generation facility including a solar cell. In the following description, the DC power supply 400 is not included in the components of the power conversion system 100. However, the DC power supply 400 may be included in the components of the power conversion system 100.

[0028] 3, the input capacitor C0 is connected between the DC power supply 400 and the DC / DC converter 2. A first electrode 111 of the input capacitor C0 is connected to a positive electrode 401 of the DC power supply 400 and a high-potential input terminal of the DC / DC converter 2. A second electrode 112 of the input capacitor C0 is connected to a negative electrode 402 of the DC power supply 400 and a low-potential input terminal of the DC / DC converter 2. The input capacitor C0 has a function of stabilizing the DC voltage output from the DC power supply 400.

[0029] The DC / DC converter 2 is a non-insulated step-up DC / DC converter. As shown in Fig. 3, the DC / DC converter 2 has an inductor L0, a diode D0, and a switching element Q0. A first end of the inductor L0 is connected to a high-potential input end of the DC / DC converter 2, and is further connected to a first electrode 111 of the input capacitor C0. A second end of the inductor L0 is connected to an anode of the diode D0. A cathode of the diode D0 is connected to a high-potential output end of the DC / DC converter 2, and is further connected to a first electrode 113 of the output capacitor C1.

[0030] The switching element Q0 is, for example, an enhancement type n-channel MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). The source of the switching element Q0 is connected to the low-potential input terminal and output terminal of the DC / DC converter 2, and is further connected to the second electrode 112 of the input capacitor C0. The drain of the switching element Q0 is connected to the connection point of the second terminal of the inductor L0 and the anode of the diode D0. The switching element Q0 is turned on / off by a control signal S0 provided by the control unit 10. The switching element Q0 is not limited to a MOSFET, and may be, for example, another semiconductor switch element such as an IGBT (Insulated Gate Bipolar Transistor) or a bipolar transistor.

[0031] The DC / DC converter 2 can boost the voltage across the input capacitor C0 by PWM (Pulse Width Modulation) control of the switching element Q0 by the control unit 10. Specifically, the control unit 10 boosts the voltage across the input capacitor C0 by switching control of the switching element Q0, and outputs the boosted DC voltage to the output capacitor C1 and the inverter 3.

[0032] 3, the output capacitor C1 is connected between the DC / DC converter 2 and the inverter 3. A first electrode 113 of the output capacitor C1 is connected to a high potential output terminal of the DC / DC converter 2 and a high potential input terminal of the inverter 3. A second electrode 114 of the output capacitor C1 is connected to an anode of the rectifier element D1 and a low potential input terminal of the inverter 3. The output capacitor C1 has a function of stabilizing the DC voltage output from the DC / DC converter 2.

[0033] 3, the anode of the rectifier element D1 is connected to the second electrode 114 of the output capacitor C1 and the low-potential input terminal of the inverter 3. The cathode of the rectifier element D1 is connected to the low-potential input terminal of the DC / DC converter 2 and is further connected to the source of the switching element Q0. The rectifier element D1 blocks current from flowing from the negative electrode 402 of the DC power supply 400 toward the output capacitor C1.

[0034] 3, the inverter 3 has four full-bridge-connected switching elements Q1 to Q4. Each of the switching elements Q1 to Q4 is, for example, a depletion-type n-channel MOSFET. Each of the switching elements Q1 to Q4 is not limited to a MOSFET, and may be, for example, an IGBT, a bipolar transistor, or another semiconductor switch element.

[0035] In the inverter 3, a series circuit of switching elements Q1 and Q3 and a series circuit of switching elements Q2 and Q4 are connected in parallel between both ends of an output capacitor C1. The drains of the switching elements Q1 and Q2 are both connected to the high potential output terminal of the DC / DC converter 2 and a first electrode 113 of the output capacitor C1. The sources of the switching elements Q3 and Q4 are both connected to the anode of the rectifier element D1 and a second electrode 114 of the output capacitor C1.

[0036] A connection point (first connection point) between the source of the switching element Q1 and the drain of the switching element Q3 is connected to the first voltage phase (phase "U" in FIG. 2) of the first system SY1 via the inductor L11 of the noise filter 4 and the first contact part 51 of the parallel-off relay 5. The first connection point is also connected to the first voltage phase (phase "L1" in FIG. 2) of the second system SY2 via the inductor L11 of the noise filter 4 and the first contact part 61 of the independent relay 6. A connection point (second connection point) between the source of the switching element Q2 and the drain of the switching element Q4 is connected to the second voltage phase (phase "W" in FIG. 2) of the first system SY1 via the inductor L12 of the noise filter 4, the measurement unit 1, and the second contact part 52 of the parallel-off relay 5. The second connection point is also connected to the second voltage phase (phase "L2" in FIG. 2) of the second system SY2 via the inductor L12 of the noise filter 4, the measurement unit 1, and the second contact part 62 of the independent relay 6. The first system SY1 is a power system that is connected to a commercial power system, and the second system SY2 is a power system that outputs AC power independently of the first system SY1.

[0037] The inverter 3 is a bidirectional DC / AC converter. In the inverter 3, the switching elements Q1 to Q4 are PWM-controlled by the control unit 10 to convert a DC voltage to an AC voltage or vice versa. That is, the inverter 3 has a function of converting the DC power from the output capacitor C1 to AC power and outputting it to the first system SY1, and a function of converting the AC power from the first system SY1 to DC power and outputting it to the output capacitor C1. In addition, the inverter 3 has a function of converting the DC power from the output capacitor C1 to AC power and outputting it to the second system SY2 when the parallel-off relay 5 is opened and the independent relay 6 is closed.

[0038] As shown in FIG. 3, the noise filter 4 has two inductors L11 and L12 and a capacitor C2. A first end of the inductor L11 is connected to a connection point (first connection point) between the source of the switching element Q1 and the drain of the switching element Q3. A second end of the inductor L11 is connected to a first contact 51 of the parallel-off relay 5 and a first contact 61 of the independent relay 6. A first end of the inductor L12 is connected to a connection point (second connection point) between the source of the switching element Q2 and the drain of the switching element Q4. A second end of the inductor L12 is connected to an input end of the measurement unit 1. An output end of the measurement unit 1 is connected to a second contact 52 of the parallel-off relay 5 and a second contact 62 of the independent relay 6. In addition, a capacitor C2 is connected between the second end of the inductor L11 and the second end of the inductor L12. The noise filter 4 has a function of removing high-frequency components of the AC voltage output from the inverter 3 and generating a sinusoidal voltage.

[0039] As shown in Fig. 3, the parallel-out relay 5 has a first contact unit 51 and a second contact unit 52. The first contact unit 51 and the second contact unit 52 are simultaneously turned on or off in response to a control signal S10 (see Fig. 2) provided from the control unit 10. The parallel-out relay 5 connects the inverter 3 in parallel with the first system SY1 when the first contact unit 51 and the second contact unit 52 are simultaneously turned on, and disconnects the inverter 3 from the first system SY1 when the first contact unit 51 and the second contact unit 52 are simultaneously turned off. In other words, the parallel-out relay 5 corresponds to the opening and closing unit 5 that opens and closes the first system SY1.

[0040] As shown in Fig. 3, the independent relay 6 has a first contact unit 61 and a second contact unit 62. The first contact unit 61 and the second contact unit 62 are simultaneously turned on or off in response to a control signal S20 (see Fig. 2) provided from the control unit 10. The independent relay 6 connects the inverter 3 in parallel with the second system SY2 when the first contact unit 61 and the second contact unit 62 are simultaneously turned on, and disconnects the inverter 3 from the second system SY2 when the first contact unit 61 and the second contact unit 62 are simultaneously turned off.

[0041] The earth leakage breaker 7 has a function of cutting off the second system SY2 when an earth leakage current flows in the second system SY2. The earth leakage breaker 7 also has a test switch. When an operator operates the test switch, an earth leakage current flows simulatively in the earth leakage breaker 7. This allows the operator to perform an operation test to check whether the earth leakage breaker 7 cuts off normally, that is, whether the earth leakage breaker 7 is operating normally.

[0042] The first current measurement unit 8 measures the current flowing through the AC side of the inverter 3. In this embodiment, as shown in Fig. 4A, the first current measurement unit 8 measures the current flowing through the first voltage phase ("U" phase) of the first system SY1 or the first voltage phase ("L1" phase) of the second system SY2. The result of measurement by the first current measurement unit 8 (measurement result) is input to the control unit 10.

[0043] The voltage measurement unit 9 measures the system voltage V0 of the first system SY1. In this embodiment, as shown in FIG. 2, the voltage measurement unit 9 measures a first system voltage V1, which is an inter-phase voltage between a first voltage phase ("U" phase) and a neutral phase ("0" phase), as the system voltage V0 of the first system SY1. In addition, the voltage measurement unit 9 measures a second system voltage V2, which is an inter-phase voltage between a second voltage phase ("W" phase) and a neutral phase ("0" phase), as the system voltage V0 of the first system SY1. The result measured by the voltage measurement unit 9 (measurement result) is input to the control unit 10.

[0044] The control unit 10 mainly comprises, for example, a computer system having one or more processors and one or more memories. That is, the functions of the control unit 10 are realized by one or more processors executing a program recorded in one or more memories of the computer system. The program may be pre-recorded in the memory, may be provided through a telecommunication line such as the Internet, or may be recorded and provided on a non-transitory recording medium such as a memory card. The control unit 10 may be composed of, for example, an FPGA (Field-Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit).

[0045] The control unit 10 outputs control signals S0-S4 for controlling the five switching elements Q0-Q4. The control signals S0-S4 are applied to the gates of the switching elements Q0-Q4 directly or via a drive circuit, and turn the switching elements Q0-Q4 on / off individually. The control unit 10 controls the switching elements Q0-Q4 by a PWM method that can adjust the duty ratio.

[0046] Furthermore, the control unit 10 outputs a control signal S10 for controlling the on / off of the first contact unit 51 and the second contact unit 52 of the parallel-off relay 5, and a control signal S20 for controlling the on / off of the first contact unit 61 and the second contact unit 62 of the independent relay 6. For example, in the event of an abnormality such as a power outage in the commercial power system, the control unit 10 causes the parallel-off relay 5 to be parallel-off from the first system SY1, and causes the independent relay 6 to be paralleled to the second system SY2. Then, in the event of an abnormality in the commercial power system, the control unit 10 controls the DC / DC converter 2 and the inverter 3 to perform an independent operation in which AC power is output from the inverter 3 to the second system SY2.

[0047] 2, the power conversion system 100 according to this embodiment further includes a grid terminal unit 22 and an independent terminal unit 23. A commercial power grid is connected to the grid terminal unit 22. In this embodiment, the grid terminal unit 22 and the independent terminal unit 23 are also housed in the first housing 101.

[0048] The system terminal unit 22 has a first system terminal, a second system terminal, and a third system terminal. The first system terminal is a terminal corresponding to a first voltage phase ("U" phase) of the first system SY1, and is connected to a first contact unit 51 of the parallel-off relay 5. The second system terminal is a terminal corresponding to a second voltage phase ("W" phase) of the first system SY1, and is connected to a second contact unit 52 of the parallel-off relay 5. The third system terminal is a terminal corresponding to a neutral phase ("0" phase) of the first system SY1, and is connected to ground.

[0049] The independent terminal unit 23 has a first independent terminal and a second independent terminal. The first independent terminal is a terminal corresponding to a first voltage phase ("L1" phase) of the second system SY2, and is connected to a first contact unit 61 of the independent relay 6 via the earth leakage breaker 7. The second independent terminal is a terminal corresponding to a second voltage phase ("L2" phase) of the second system SY2, and is connected to a second contact unit 62 of the independent relay 6 via the earth leakage breaker 7.

[0050] (2.4) Measurement Unit Next, the configuration of a measurement unit (measurement device) 1 according to this embodiment will be described with reference to FIG. 4A.

[0051] The measurement unit 1 according to this embodiment is configured to be detachable from the power conversion system 100 as described above. That is, the power conversion system 100 includes a terminal unit 21 that electrically connects the inverter 3 (power conversion unit) and the measurement unit 1 (measurement unit). In this embodiment, the measurement unit 1 can be electrically connected to a path between the noise filter 4 and the parallel-off relay 5 and the independent relay 6, as shown in FIG. 4A. That is, the measurement unit 1 can measure AC power in both the first system SY1 and the second system SY2 by being connected to the path between the noise filter 4 and the parallel-off relay 5 and the independent relay 6. In other words, the measurement unit (measurement unit) 1 is provided at a position where it can measure AC power in both the first system SY1 and the second system SY2. This makes it possible to measure both the AC power of the first system SY1 and the AC power of the second system SY2. For example, when the above-mentioned DC power supply 400 is rented, it is necessary to measure the amount of power (power generation amount) when the second system SY2 is operating independently during a power outage in the commercial power system, and this is effective in such a case.

[0052] As shown in Fig. 4A, the measurement unit 1 includes a second current measurement unit 11, a current detection unit 12, a voltage detection unit 13, a power supply unit 14, a control unit 15, a communication unit 16, a pulse generation unit 17, an attachment / detachment detection unit 18, and a memory unit 19. The second current measurement unit 11, the current detection unit 12, the voltage detection unit 13, the power supply unit 14, the control unit 15, the communication unit 16, the pulse generation unit 17, the attachment / detachment detection unit 18, and the memory unit 19 are housed in a single second housing 25 (see Fig. 5A). The second housing 25 is formed, for example, in a rectangular parallelepiped shape.

[0053] The second current measurement unit 11 measures the current flowing through the AC side of the inverter 3. In this embodiment, the second current measurement unit 11 measures the current flowing through the second voltage phase ("W" phase) of the first system SY1 or the second voltage phase ("L2" phase) of the second system SY2. The result of measurement by the second current measurement unit 11 (measurement result) is input to the current detection unit 12.

[0054] The current detection unit 12 has a function of converting an analog signal of the current measured by the second current measurement unit 11 into a digital signal. The digital signal converted by the current detection unit 12 is input to the control unit 15.

[0055] The voltage detection unit 13 has a function of measuring the correlation voltage between the first voltage phase ("U" phase) and the second voltage phase ("W" phase) of the first system SY1, or the correlation voltage between the first voltage phase ("L1" phase) and the second voltage phase ("L2" phase) of the second system SY2. The voltage detection unit 13 also has a function of converting the analog signal of the measured correlation voltage into a digital signal. The digital signal converted by the voltage detection unit 13 is input to the control unit 15.

[0056] The power supply unit 14 has, for example, an AC / DC converter. The power supply unit 14 converts the AC power output from the inverter 3 into DC power suitable for the operation of the control unit 15, etc. The power supply unit 14 outputs the generated DC power to the current detection unit 12, the voltage detection unit 13, the control unit 15, the communication unit 16, the pulse generation unit 17, and the storage unit 19.

[0057] The control unit 15 mainly comprises, for example, a computer system having one or more processors and one or more memories. That is, the functions of the control unit 15 (including the writing unit 151) are realized by one or more processors executing a program recorded in one or more memories of the computer system. The program may be pre-recorded in the memory, may be provided through a telecommunication line such as the Internet, or may be recorded and provided on a non-transitory recording medium such as a memory card. The control unit 15 may be composed of, for example, an FPGA or an ASIC.

[0058] The control unit 15 calculates (measures) an integrated value of AC power, which is the power on the AC side of the inverter 3, based on the detection result of the current detection unit 12 and the detection result of the voltage detection unit 13. Specifically, the control unit 15 calculates, for example, an integrated amount of power for 30 minutes (30-minute demand value). Here, as shown in FIG. 4A, the control unit 15 has a writing unit 151. The writing unit 151 performs a process of writing the 30-minute demand value calculated by the control unit 15 into the storage unit 19. That is, the writing unit 151 performs a process of writing the measurement result of the measurement unit 1 into the storage unit 19. The control unit 15 is also configured to control the communication unit 16 and the pulse generation unit 17 separately.

[0059] Incidentally, when the DC power supply 400 is interconnected with a commercial power system as in the power conversion system 100 according to the present embodiment, it is possible to supply power from the DC power supply 400 even during a power outage in the commercial power system. Therefore, in this case, the writing process by the writing unit 151 to the storage unit 19 may be delayed compared to when the DC power supply 400 is not interconnected with the commercial power system. In other words, when the DC power is equal to or greater than the threshold power, the writing unit 151 may delay writing to the storage unit 19 compared to when the DC power is less than the threshold power. When the DC power supply 400 is a solar power generation facility as in the present embodiment, it is preferable to set the delay time to about 30 minutes before sunset.

[0060] The communication unit 16 includes a communication interface for communicating with the external device 500. In the present embodiment, as an example, the communication unit 16 performs bidirectional wireless communication with the external device 500. The communication method between the communication unit 16 and the external device 500 is, for example, a wireless multi-hop method or an N wireless method. The external device 500 is, for example, a server device of an electric power company (electricity transmission and distribution business operator).

[0061] The pulse generating unit 17 has, for example, an infrared LED (Light Emitting Diode). The pulse generating unit 17 generates a pulse signal according to the power value of the AC power calculated by the control unit 15.

[0062] The attachment / detachment detection unit 18 detects whether or not the measuring unit 1 is attached to the power conversion system 100. In other words, the attachment / detachment detection unit 18 detects whether or not the inverter 3 and the measuring unit 1 are electrically connected. The control unit 15 determines whether or not the measuring unit 1 is attached (connected) to the power conversion system 100 according to the detection result of the attachment / detachment detection unit 18.

[0063] The storage unit 19 appropriately stores the 30-minute demand value calculated by the control unit 15 and the like. The storage unit 19 is realized by a rewritable non-volatile memory such as an EEPROM (Electrically Erasable Programmable Read-Only Memory). In this embodiment, it is preferable that the storage unit 19 further includes an area with special security (for example, a tamper-resistant area). The "area with special security" here means two cases: a case where one memory includes two areas, and a case where the memory has memories with physically different security. In this embodiment, an electronic certificate for connection with the external device 500 and measurement parameters are stored in the "area with special security" of the storage unit 19.

[0064] (3) Structure of the measuring unit Next, the structure of the measurement unit 1 according to this embodiment will be described with reference to Figures 4A and 4B. In Figures 4A and 4B, the voltage measurement section 9 and the control section 10 are omitted.

[0065] As described above, the measurement unit 1 is configured to be detachable from the power conversion system 100. More specifically, the measurement unit 1 is configured to be electrically connectable to the inverter 3 of the power conversion system 100 by the terminal unit 21. As shown in FIG. 4A, the terminal unit 21 has a pair of current connection terminals 211 and a pair of voltage connection terminals 212. The pair of current connection terminals 211 are terminals for connecting the second current measurement unit 11 and the current detection unit 12 to the power conversion system 100, and it is possible to measure the current flowing through the AC side of the inverter 3 via the pair of current connection terminals 211. The pair of voltage connection terminals 212 are terminals for connecting the voltage detection unit 13 to the current conversion system 100, and it is possible to measure the AC voltage applied to the AC side of the inverter 3 via the pair of voltage connection terminals 212.

[0066] Moreover, the measurement unit 1 according to the present embodiment includes the attachment / detachment detection unit 18 as described above. This makes it possible to determine whether the measurement unit 1 is normally attached to the power conversion system 100, that is, whether the measurement unit 1 is electrically connected to the power conversion system 100. Here, the measurement unit 1 according to the present embodiment includes the communication unit 16 as described above. Therefore, it is possible to notify the external device 500 via the communication unit 16 that the measurement unit 1 is normally attached to the power conversion system 100. Therefore, the external device 500 can know that the measurement unit 1 is normally attached to the power conversion system 100 without going to the facility F1 where the power conversion system 100 is installed.

[0067] Furthermore, when the measurement unit 1 is not connected to the power conversion system 100, the short-circuiting unit 20 can be connected to the power conversion system 100 to make the power conversion system 100 function, as shown in Fig. 4B. As shown in Fig. 4B, the short-circuiting unit 20 has a short-circuiting piece 201. A first end of the short-circuiting piece 201 is connected to one of a pair of current connection terminals 211, and a second end of the short-circuiting piece 201 is connected to the other of the pair of current connection terminals 211. Then, by connecting the short-circuiting unit 20 to the power conversion system 100 via the terminal portion 21, it becomes possible to normally connect paths between the noise filter 4 and the parallel-off relay 5 and the independent relay 6 (see Fig. 4B).

[0068] (4) Sealing structure of the measurement unit Since there is a possibility that the power measured by the measuring unit 1 may be subject to billing, it is preferable that the second housing 25 of the measuring unit 1 has sealing structures 251 to 253 to prevent tampering with the power. The sealing structures 251 to 253 of the second housing 25 will be described below with reference to Figs. 5A to 5C.

[0069] 5A includes a sealing portion 2511 and a sealing cap 2512. The sealing portion 2511 is, for example, in the shape of a round bar, and protrudes from a side surface of the second housing 25. The sealing cap 2512 is in the shape of a rectangular box with one surface (the surface facing the sealing portion 2511) open. In this sealing structure 251, the second housing 25 is sealed by covering the sealing portion 2511, which is inserted into the groove portion 2513 of the second housing 25, with the sealing cap 2512 when the second housing 25 is assembled.

[0070] 5B includes a first attachment portion 2521 and a second attachment portion 2522. In this sealing structure 252, when the second housing 25 is assembled, a protrusion provided on the first attachment portion 2521 fits into a hole provided on the second attachment portion 2522, thereby sealing the second housing 25.

[0071] 5C includes a sealing wire 2531 and a sealing member 2532. In this sealing structure 253, the second housing 25 is sealed by sealing both ends of the sealing wire 2531, which is inserted through a first member 254 and a second member 255 provided in the second housing 25, with the sealing member 2532.

[0072] Furthermore, the sealing structure may be formed, for example, of a special screw that requires a special tool, or a security seal (an anti-tamper seal, a sealing seal) that has a function of indicating that the package has been opened.

[0073] The above-described sealing structure can prevent the second housing 25 from being opened. In this case, the power conversion system 100 may or may not be stopped when the second housing 25 is opened.

[0074] The sealing structure may be formed of a seal or wire attached so as to straddle both the power conversion system 100 and the measurement unit 1 inside the first housing 101. In this case, it is possible to prevent the measurement unit 1 from being removed from the power conversion system 100.

[0075] (5) Effects (5.1) Power Conversion System As described above, the power conversion system 100 according to this embodiment includes the power conversion section (inverter) 3, the measurement section (measurement unit) 1, and the terminal section 21. The power conversion section 3 performs power conversion between DC power and AC power. The measurement section 1 measures at least one of the DC power and the AC power. The terminal section 21 electrically connects the power conversion section 3 and the measurement section 1.

[0076] As described above, in the power conversion system 100 according to this embodiment, the measurement unit 1 is electrically connected to the power conversion unit 3 of the power conversion system 100 via the terminal unit 21. This allows the measurement unit 1 to measure at least one of DC power, which is the power on the DC side of the power conversion unit 3, and AC power, which is the power on the AC side of the power conversion unit 3. Therefore, according to the power conversion system 100 according to this embodiment, it is possible to expand the measurement range compared to the conventional configuration in which the smart meter 300 measures AC power.

[0077] Moreover, in the power conversion system 100 according to this embodiment, as described above, the measurement unit 1 is electrically connected to the power conversion unit 3 by the terminal unit 21. Therefore, according to the power conversion system 100 according to this embodiment, it is possible to detachably connect the measurement unit 1.

[0078] (5.2) Measurement Equipment The measurement device (measurement unit) 1 according to this embodiment functions as the measurement section 1 of the above-mentioned power conversion system 100. The measurement device 1 is electrically connected to the power conversion section (inverter) 3 by a terminal section 21.

[0079] The measuring device 1 according to this embodiment is used in the above-described power conversion system 100, and therefore, the measuring range can be expanded and the measuring device 1 can be detachably connected to the power conversion system 100.

[0080] (6) 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. Below, modified examples of the above-described embodiment are listed. The modified examples described below can be applied in appropriate combination.

[0081] (6.1) Variation 1 A power conversion system 100 according to the first modification will be described with reference to Fig. 6. In Fig. 6, the voltage measurement unit 9 and the control unit 10 are omitted from the illustration.

[0082] 6, the power conversion system 100 according to the first modification is different from the power conversion system 100 according to the above-described embodiment in that the second current measurement unit 11 is provided near the grid terminal unit 22. Other configurations are similar to those of the power conversion system 100 according to the above-described embodiment, and the same components are denoted by the same reference numerals and will not be described.

[0083] In the power conversion system 100 according to the first modification, the measurement unit 1 has a second current measurement unit 11 as shown in Fig. 6. The second current measurement unit 11 measures a current flowing through the AC side of the inverter 3. As shown in Fig. 6, the second current measurement unit 11 is provided on a path between the parallel-off relay 5 and the grid terminal unit 22. In other words, the second current measurement unit 11 is provided on the grid terminal unit 22 side of the path between the inverter 3 and the grid terminal unit 22.

[0084] In the power conversion system 100 according to the first modification, the second current measurement unit 11 is provided at a position closer to the smart meter 300 than in the power conversion system 100 according to the above-described embodiment (see Figs. 4A and 6). Therefore, according to the power conversion system 100 according to the first modification, it is possible to obtain a measurement value closer to the measurement value in the smart meter 300 than in the power conversion system 100 according to the above-described embodiment.

[0085] (6.2) Variation 2 A power conversion system 100 according to the second modification will be described with reference to FIG. 7A.

[0086] The power conversion system 100 according to the second modification is different from the power conversion system 100 according to the above-mentioned embodiment in that the measurement unit 1a further includes a notification unit 30, as shown in Fig. 7A. The power conversion system 100 according to the second modification is also different from the power conversion system 100 according to the above-mentioned embodiment in that the control unit 15a further includes a tamper detection unit 152, as shown in Fig. 7A. Other configurations are the same as those of the power conversion system 100 according to the above-mentioned embodiment, and the same components are denoted by the same reference numerals and will not be described.

[0087] The tampering detection unit 152 detects at least one of tampering of the 30-minute demand value, which is the measurement result of the measurement unit 1, and tampering of the 30-minute demand value stored in the storage unit 19. In the present embodiment, as an example, the tampering detection unit 152 detects tampering of the 30-minute demand value stored in the storage unit 19. When the writing unit 151 writes the 30-minute demand value in the storage unit 19, the control unit 15a calculates a hash value based on the 30-minute demand value, and writes the 30-minute demand value and the hash value in the storage unit 19. Then, when reading the 30-minute demand value, the tampering detection unit 152 detects tampering of the 30-minute demand value by using the 30-minute demand value and the hash value. Note that the hash value may be written in the above-mentioned "specially secured area" of the storage unit 19. That is, the hash value may be written to a normal area of ​​the storage unit 19 (an area where special security is not ensured), or may be written to an area of ​​the storage unit 19 where special security is ensured.

[0088] The notification unit 30 includes, for example, a liquid crystal display. For example, when the tampering detection unit 152 detects tampering of the 30-minute demand value stored in the storage unit 19, the notification unit 30 displays the fact on the liquid crystal display. This makes it possible to notify a user (for example, a resident of the facility F1) that the 30-minute demand value has been tampered with. In addition, by transmitting the detection result of the tampering detection unit 152 to the external device 500 via the communication unit 16, it is also possible to notify an electric power company or the like that the 30-minute demand value has been tampered with.

[0089] Here, since the measuring unit 1a is composed of multiple electronic components, inspection or replacement may be required after a certain period of time (e.g., 10 years). Therefore, it is preferable that the notification unit 30 notifies the user that the measuring unit 1a needs to be inspected or replaced after the certain period of time has passed. Specifically, the notification unit 30 displays on the liquid crystal display that the measuring unit 1a needs to be inspected or replaced. This makes it possible to notify the user that the measuring unit 1a needs to be inspected or replaced.

[0090] Here, it is assumed that the measuring unit 1a is replaced. In this case, the measuring unit 1a may be replaced as a whole, or only the parts with a limited life span may be replaced. For example, if the EEPROM constituting the storage unit 19 is detachable, only the EEPROM may be replaced.

[0091] Furthermore, the fact that inspection and replacement of the measuring unit 1a is necessary may be displayed (notified) on, for example, a smartphone, tablet, or personal computer carried by the user.

[0092] (6.3) Variation 3 The power conversion system 100 according to the third modification will be described with reference to FIG. 7B.

[0093] 7B, the power conversion system 100 according to the third modification is different from the power conversion system 100 according to the second modification in that the control unit 15b further includes a disconnection detection unit 153. Other configurations are the same as those of the power conversion system 100 according to the above-described embodiment, and the same components are denoted by the same reference numerals and will not be described.

[0094] The disconnection detection unit 153 detects a disconnection in the measurement unit 1b. As an example, assume that a disconnection occurs in the second current measurement unit 11. In this case, the measurement result of the second current measurement unit 11 is no longer input to the control unit 15b, and the disconnection detection unit 153 determines that a disconnection has occurred based on the fact that the measurement result of the second current measurement unit 11 is no longer input to the control unit 15b.

[0095] In this case, it is preferable that the notification unit 30 notifies that a disconnection has occurred in the measurement unit 1b. That is, it is preferable that the notification unit 30 notifies that a disconnection has been detected in the measurement unit 1b by the disconnection detection unit 153. This makes it possible to notify the user that a disconnection has occurred in the measurement unit 1b.

[0096] (6.4) Variation 4 A power conversion system 100 according to the fourth modification will be described with reference to FIG.

[0097] 8, the power conversion system 100 according to the fourth modification is different from the power conversion system 100 according to the above-mentioned embodiment in that it further includes a communication unit 31. Note that other configurations are similar to those of the power conversion system 100 according to the above-mentioned embodiment, and the same components are denoted by the same reference numerals and description thereof will be omitted.

[0098] 8, the communication unit 31 includes a communication interface for communicating with the external device 500. In the fourth modification, as an example, the communication unit 31 performs wireless communication with the external device 500. The communication method between the communication unit 31 and the external device 500 is, for example, a wireless multi-hop method or an N wireless method. As described above, the external device 500 is, for example, a server device provided in an electric power company (electricity transmission and distribution business operator).

[0099] In this case, the power conversion system 100 is preferably configured to disconnect the parallel-off relay 5 in response to a parallel-off instruction from the external device 500. Specifically, the external device 500 creates an open signal including a parallel-off instruction for disconnecting the parallel-off relay 5, and transmits the created open signal to the communication unit 31 of the power conversion system 100. In the power conversion system 100, when the communication unit 31 receives the open signal, the control unit 10 outputs a control signal S10 for disconnecting the parallel-off relay 5 to the parallel-off relay 5 in accordance with the parallel-off instruction included in the open signal. The parallel-off relay 5 is disconnected in accordance with the control signal S10 from the control unit 10. This makes it possible to disconnect the DC power supply 400 from the commercial power system. In this way, the power conversion system 100 according to the fourth modification makes it possible to disconnect the parallel-off relay 5 by remote control. In the power conversion system 100 according to the fourth modification, the parallel-off relay 5 corresponds to the switching unit 5 for opening and closing the first system SY1 on the AC side of the inverter 3.

[0100] In the fourth modification, the communication between the communication unit 31 and the external device 500 is wireless communication, but it may be wired communication. In this case, it is preferable that the communication be power line communication (PLC) using the power lines of a commercial power system.

[0101] (6.5) Variation 5 A power conversion system 100 according to the fifth modification will be described with reference to FIGS.

[0102] The power conversion system 100 according to the fifth modification is different from the power conversion system 100 according to the above-mentioned embodiment in that a measuring unit 1c is integrally incorporated into the power conversion system 100. The power conversion system 100 according to the fifth modification is also different from the power conversion system 100 according to the above-mentioned embodiment in that the power conversion system 100 according to the fifth modification further includes a plurality of (three in the illustrated example) inspection terminals 41 to 43 and an inspection relay 24. Other configurations are the same as those of the power conversion system 100 according to the above-mentioned embodiment, and the same components are denoted by the same reference numerals and description thereof will be omitted.

[0103] The multiple inspection terminals 41 to 43 include a first inspection terminal 41, a second inspection terminal 42, and a third inspection terminal 43. The first inspection terminal 41 is connected to a second end of the first contact portion 241 of the inspection relay 24. The first end of the first contact portion 241 of the inspection relay 24 is connected to the noise filter 4. The second inspection terminal 42 is connected to a first end of the first contact portion 61 of the self-supporting relay 6. The second end of the first contact portion 61 of the self-supporting relay 6 is connected to the earth leakage breaker 7. The third inspection terminal 43 is connected to a first end of the second contact portion 62 of the self-supporting relay 6. The second end of the second contact portion 62 of the self-supporting relay 6 is connected to the earth leakage breaker 7.

[0104] The inspection relay 24 has a first contact portion 241 and a second contact portion 242. The first contact portion 241 and the second contact portion 242 are simultaneously turned on or off by a control signal provided from the control unit 10. When the first contact portion 241 and the second contact portion 242 are simultaneously turned on, the inspection relay 24 connects the inverter 3 to the first system SY1 or the second system SY2 in parallel, and when the first contact portion 241 and the second contact portion 242 are simultaneously turned off, the inspection relay 24 disconnects the inverter 3 from the first system SY1 and the second system SY2. Here, the inspection relay 24 is a relay for inspecting the measurement unit 1c integrally incorporated in the power conversion system 100, and the inspection relay 24 is disconnected only when the measurement unit 1c is to be inspected.

[0105] Next, a method for inspecting the measuring unit 1c will be described with reference to FIG.

[0106] First, the first inspection terminal 41, the second inspection terminal 42, the third inspection terminal 43, and the pulse generating unit 17 are connected to an inspection device 600 for inspecting the measuring unit 1c (see FIG. 10). In addition, the parallel-off relay 5, the independent relay 6, and the inspection relay 24 are each disconnected. This causes the measuring unit 1c to be separated from the power conversion system 100, and a closed circuit including the inspection device 600 is formed.

[0107] Next, the inspection device 600 is started. When the inspection device 600 is started, the inspection device 600 applies an AC voltage to the closed circuit and outputs an AC current. The inspection device 600 calculates AC power from the AC voltage and the AC current. The inspection device 600 also acquires a pulse signal corresponding to the AC power measured by the measurement unit 1c from the pulse generating unit 17. For example, the inspection device 600 compares the waveform of the AC power with the waveform of the pulse signal, and if the two match, it determines that the measurement unit 1c is normal, and if the two do not match, it determines that the measurement unit 1c is abnormal. The term "match" here includes not only the case where the two comparison targets are completely the same, but also the case where the two comparison targets are different enough to be considered to be the same.

[0108] According to the power conversion system 100 of the fifth modification, even if the measuring unit 1c is integrated into the power conversion system 100, the inspection device 600 can inspect the measuring unit 1c.

[0109] Furthermore, when both the first current measuring unit 8 and the second current measuring unit 11 are provided, as in the power conversion system 100 of variant example 5, it is also possible to inspect the current measuring units by comparing the measurement results of the first current measuring unit 8 and the measurement results of the second current measuring unit 11.

[0110] (6.6) Variation 6 A power conversion system 100a according to the sixth modification will be described with reference to FIG.

[0111] The power conversion system 100a according to the sixth modification differs from the power conversion system 100 according to the above-described embodiment in that the power conversion system 100a converts AC power supplied from a commercial power system into DC power for the battery of the electric vehicle 700. That is, the power conversion system 100a according to the sixth modification is a unidirectional power conversion system that performs power conversion only in the second direction.

[0112] The power conversion system 100a according to the sixth modification is supplied with AC power P31 excluding AC power P32 consumed by load devices from AC power P3 supplied from a commercial power system via a smart meter 300. The power conversion system 100a then converts the AC power P31 into DC power and outputs the converted DC power to a battery of the electric vehicle 700.

[0113] In the power conversion system 100a according to the sixth modification, a measurement unit incorporated in the power conversion system 100a makes it possible to measure the AC power P31 used to charge the battery of the electric vehicle 700. In this case, the measurement unit is connected to the AC side of the power conversion section included in the power conversion system 100a.

[0114] (6.7) Other Modifications The power conversion system 100 in the present disclosure includes a computer system in the control unit 10, for example. The computer system is mainly composed of a processor and a memory as hardware. The processor executes a program recorded in the memory of the computer system, thereby realizing the function of the power conversion system 100 in the present disclosure. The program may be pre-recorded in the memory of the computer system, may be provided through an electric communication line, or may be provided by being recorded in a non-transitory recording medium such as a memory card, an optical disk, or a hard disk drive that can be read by the computer system. The processor of the computer system is composed of one or more electronic circuits including a semiconductor integrated circuit (IC) or a large-scale integrated circuit (LSI). The integrated circuits such as IC or LSI here are called by different names depending on the degree of integration, and include integrated circuits called system LSI, VLSI (Very Large Scale Integration), or ULSI (Ultra Large Scale Integration). Furthermore, a field-programmable gate array (FPGA) that is programmed after the manufacture of the LSI, or a logic device that can reconfigure the connection relationship inside the LSI or the circuit partition inside the LSI, can also be adopted as a processor. The electronic circuits may be integrated in one chip or distributed among multiple chips. The chips may be integrated in one device or distributed among multiple devices. The computer system referred to here includes a microcontroller having one or more processors and one or more memories. Thus, the microcontroller is also composed of one or more electronic circuits including a semiconductor integrated circuit or a large-scale integrated circuit.

[0115] Furthermore, it is not essential for the power conversion system 100 that multiple functions are concentrated in one housing. The components of the power conversion system 100 may be distributed across multiple housings. Furthermore, at least some of the functions of the power conversion system 100, for example, the functions of the control unit 10, may be realized by the cloud (cloud computing) or the like.

[0116] Furthermore, it is not essential for the measurement unit 1 that multiple functions are integrated into one housing. The components of the measurement unit 1 may be distributed across multiple housings. Furthermore, at least some of the functions of the measurement unit 1, for example, the functions of the control unit 15, may be realized by the cloud (cloud computing) or the like.

[0117] In the above-described embodiment, the measurement unit 1 has the second current measuring unit 11, but is not limited to this. The measurement unit 1 may measure AC power based on the current measured by the first current measuring unit 8, for example. In other words, the first current measuring unit 8 may also serve as the current measuring unit of the measurement unit 1. This eliminates the need for the second current measuring unit 11, making it possible to reduce the number of parts.

[0118] In the above embodiment, the measurement unit 1 measures AC power, which is the power on the AC side of the inverter 3, but this is not limited to the above. The measurement unit 1 may measure DC power, which is the power on the DC side of the inverter 3, or may measure both AC power and DC power.

[0119] In the above embodiment, the power conversion system 100 is a unidirectional power conversion system that performs power conversion only in a first direction, but is not limited thereto. The power conversion system 100 may be a bidirectional power conversion system that performs power conversion in both the first and second directions.

[0120] In the above-described embodiment, the measurement unit 1 is built into the first housing 101, but this is not limiting. The measurement unit 1 may be provided separately from the first housing 101. In other words, the measurement unit (measurement section) 1 may be located outside the first housing 101 while being connected to the terminal section 21. This makes it possible to retrofit the measurement unit 1 to an existing power conversion system 100.

[0121] In the above embodiment, the attachment / detachment detection unit 18 detects attachment / detachment of the measurement unit 1 from the power conversion system 100, but this is not limited thereto. For example, when the measurement unit 1 is detached from the power conversion system 100, the power supply from the power supply unit 14 stops, and the communication unit 16 cannot communicate with the external device 500. Therefore, the external device 500 can determine that the measurement unit 1 has been detached from the power conversion system 100 when communication with the communication unit 16 becomes impossible. In other words, the measurement unit 1 may be detected as being detached from the power conversion system 100 when communication between the external device 500 and the communication unit 16 becomes impossible.

[0122] In the above embodiment, there is one first current measuring unit 8, but there may be more than one. Also, in the above embodiment, there is one second current measuring unit 11, but there may be more than one. Since the possibility of multiple current measuring units being disconnected at the same time is low, even if any one of the current measuring units is disconnected, it is possible for the remaining current measuring units to continue measuring the current.

[0123] In the above embodiment, at least one of the 30-minute demand value, which is the measurement result of the measurement unit 1, and the 30-minute demand value stored in the storage unit 19 is subject to tampering, but this is not limiting. For example, at least one of the electronic certificate for connection with the external device 500 (server device) and the measurement parameters may be subject to tampering.

[0124] In the above embodiment, the sealing structures 251 to 253 are provided in the second housing 25 that houses the measurement unit 1, but the sealing structures may be provided in the first housing 101, for example.

[0125] (Aspect) The following aspects are disclosed from the above-described embodiment and modified examples.

[0126] A power conversion system (100; 100a) according to a first embodiment includes a power conversion unit (3), a measurement unit (1), and a terminal unit (21). The power conversion unit (3) performs power conversion between DC power and AC power. The measurement unit (1) measures at least one of the DC power and the AC power. The terminal unit (21) electrically connects the power conversion unit (3) and the measurement unit (1).

[0127] According to this aspect, at least one of the DC power, which is the power on the DC side of the power conversion unit (3), and the AC power, which is the power on the AC side of the power conversion unit (3), is measured. This makes it possible to expand the measurement range compared to the conventional configuration in which the smart meter (300) measures AC power.

[0128] The power conversion system (100; 100a) according to the second aspect is the same as the first aspect, and further includes a housing (101). The housing (101) houses the power conversion unit (3) and the measurement unit (1).

[0129] According to this embodiment, the measuring unit (1) can also be housed within the housing (101).

[0130] The power conversion system (100; 100a) according to the third aspect is the same as the first aspect, and further includes a housing (101). The housing (101) houses the power conversion unit (3). The measurement unit (1) is located outside the housing (101) in a state where it is connected to the terminal unit (21).

[0131] According to this embodiment, it is possible to retrofit the measuring unit (1) to an existing power conversion system (100; 100a).

[0132] The power conversion system (100; 100a) according to the fourth aspect is the power conversion system according to the second or third aspect, and further includes a second housing (25). The second housing (25) is different from the first housing (101) as the housing (101). The second housing (25) has a sealing structure (251-253). The sealing structure (251-253) prevents the second housing (25) from being opened while the measuring unit (1) is stored therein.

[0133] According to this embodiment, it is possible to prevent the second housing (25) from being opened.

[0134] A power conversion system (100; 100a) according to a fifth aspect is any one of the first to fourth aspects, further including a current measurement unit (8). The current measurement unit (8) measures a current flowing through an AC side of the power conversion unit (3). The measurement unit (1) measures AC power based on the current measured by the current measurement unit (8).

[0135] According to this embodiment, the current measuring unit (8) of the power conversion unit (3) can be used as well, thereby making it possible to reduce the number of parts.

[0136] A power conversion system (100; 100a) according to a sixth aspect is any one of the first to fourth aspects, further including a grid terminal unit (22). The grid terminal unit (22) is provided on the AC side of the power conversion unit (3) and is connectable to a commercial power system. The measurement unit (1) has a current measurement unit (11). The current measurement unit (11) measures a current flowing on the AC side of the power conversion unit (3). The current measurement unit (11) is provided on the grid terminal unit (22) side in a path between the power conversion unit (3) and the grid terminal unit (22).

[0137] According to this embodiment, it is possible to measure AC power at a location close to the smart meter (300).

[0138] In a power conversion system (100; 100a) according to a seventh aspect, in any one of the first to fourth aspects, the measurement unit (1) is provided at a position capable of measuring AC power in both the first system (SY1) and the second system (SY2). The first system (SY1) is a system connected to a commercial power system on the AC side of the power conversion unit (3). The second system (SY2) is a system that outputs AC power independently of the first system (SY1) on the AC side of the power conversion unit (3).

[0139] According to this embodiment, it is possible to measure both the AC power of the first system (SY1) and the AC power of the second system (SY2).

[0140] A power conversion system (100; 100a) according to an eighth aspect is any one of the first to seventh aspects, and further includes a storage unit (19) and a writing unit (151). The writing unit (151) writes the measurement result of the measuring unit (1) into the storage unit (19). When the DC power is equal to or greater than a threshold power, the writing unit (151) delays writing into the storage unit (19) compared to when the DC power is less than the threshold power.

[0141] According to this embodiment, it is possible to change the timing of writing to the storage unit (19).

[0142] A power conversion system (100; 100a) according to a ninth aspect is the same as the eighth aspect, and further includes a tamper detection unit (152) and a notification unit (30). The tamper detection unit (152) detects at least one of tampering of the measurement results of the measurement unit (1) and tampering of the measurement results stored in the memory unit (19). The notification unit (30) notifies that the tampering detection unit (152) has detected tampering of the measurement results.

[0143] According to this aspect, it is possible to notify that at least one of the measurement results of the measurement unit (1) and the measurement results stored in the memory unit (19) has been tampered with.

[0144] The power conversion system (100) according to a tenth aspect is any one of the first to ninth aspects, further including a notification unit (30). The notification unit (30) notifies that inspection of the measurement unit (1) or replacement of the measurement unit (1) is required.

[0145] According to this aspect, it is possible to notify that inspection of the measuring unit (1) or replacement of the measuring unit (1) is necessary.

[0146] A power conversion system (100; 100a) according to an eleventh aspect is any one of the first to tenth aspects, further including a disconnection detection unit (153) and a notification unit (30). The disconnection detection unit (153) detects a disconnection in the measurement unit (1). The notification unit (30) notifies that the disconnection detection unit (153) has detected the disconnection in the measurement unit (1).

[0147] According to this embodiment, it is possible to notify of a disconnection in the measuring unit (1).

[0148] A power conversion system (100; 100a) according to a twelfth aspect is any one of the first to eleventh aspects, and further includes a communication unit (31), a switch unit (5), and a control unit (10). The communication unit (31) communicates with the outside (external device 500). The switch unit (5) opens and closes the power system (SY1) on the AC side of the power conversion unit (3). The control unit (10) controls the switch unit (5). The communication unit (31) receives an open signal to open the switch unit (5). The control unit (10) opens the switch unit (5) based on the open signal received by the communication unit (31).

[0149] According to this embodiment, the opening / closing section (5) can be opened by remote control.

[0150] A measurement device (1) according to the thirteenth aspect functions as a measurement section (1) of the power conversion system (100; 100a) according to any one of the first to twelfth aspects. The measurement device (1) is electrically connected to the power conversion section (3) by a terminal section (21).

[0151] According to this aspect, at least one of the DC power, which is the power on the DC side of the power conversion unit (3), and the AC power, which is the power on the AC side of the power conversion unit (3), is measured, making it possible to expand the measurement range compared to the conventional configuration in which AC power is measured by a smart meter.

[0152] The configurations according to the second to twelfth aspects are not essential for the power conversion system (100; 100a) and can be omitted as appropriate. [Explanation of symbols]

[0153] 1. Measurement unit (measurement section, measurement device) 3. Inverter (power conversion section) 5. Parallel-off relay (switching section) 8 First current measuring unit (current measuring unit) 10 Control section 11 Second current measurement unit (current measurement unit) 19 Memory section 30. Notification Department 31 Communications Department 21 Terminal section 22 System terminal section 25 Second cabinet 100,100a power conversion system 101 1st cabinet (cabinet) 151 Writing section 152 Tampering detection unit 153 Disconnection detection unit 251~253 Sealing structure 500 External device SY1 1st system (power system) SY2 2nd system

Claims

1. a power conversion unit that performs power conversion between DC power and AC power; a measurement unit that measures at least one of the DC power and the AC power; a terminal unit electrically connecting the power conversion unit and the measurement unit, The power conversion unit and the measurement unit are integrated together, a plurality of inspection terminals for electrically connecting an inspection device that inspects the measurement unit to the measurement unit; an inspection relay that is switched to a first state in which the power conversion unit and the measurement unit are connected, or a second state in which the measurement unit is disconnected from the power conversion unit; The inspection relay is switched to the second state when the inspection device inspects the measurement unit. Power conversion systems.

2. Further comprising a housing for housing the power conversion unit and the measurement unit. The power conversion system of claim 1 .

3. Further comprising a housing for housing the power conversion unit, the power conversion unit and the measurement unit are integrated via the terminal unit, The measurement unit is located outside the housing while being connected to the terminal unit. The power conversion system of claim 1 .

4. Further comprising a current measuring unit that measures a current flowing through an AC side of the power conversion unit, The measurement unit measures the AC power based on the current measured by the current measurement unit. The power conversion system according to any one of claims 1 to 3.

5. The power converter further includes a system terminal unit provided on an AC side of the power converter and capable of connecting to a commercial power system, The measurement unit has a current measurement unit that measures a current flowing through an AC side of the power conversion unit, The current measuring unit is provided on the side of the grid terminal unit in a path between the power conversion unit and the grid terminal unit. The power conversion system according to any one of claims 1 to 3.

6. The measurement unit is provided at a position capable of measuring the AC power in both a first system connected to a commercial power system on the AC side of the power conversion unit and a second system outputting the AC power independently of the first system on the AC side of the power conversion unit. The power conversion system according to any one of claims 1 to 3.

7. A memory unit; A writing unit that writes the measurement result of the measuring unit into the memory unit, the writing unit delays writing to the storage unit when the DC power is equal to or greater than a threshold power, compared to when the DC power is less than the threshold power. The power conversion system according to any one of claims 1 to 6.

8. A tamper detection unit that detects at least one of tampering with the measurement results of the measurement unit and tampering with the measurement results stored in the memory unit; and a notification unit that notifies that the tampering detection unit has detected tampering of the measurement result. The power conversion system of claim 7.

9. Further comprising an alarm unit that notifies that inspection of the measuring unit or replacement of the measuring unit is necessary. The power conversion system according to any one of claims 1 to 8.

10. A disconnection detection unit that detects a disconnection of the measurement unit; and a notification unit that notifies that a break in the measurement unit has been detected by the break detection unit. The power conversion system according to any one of claims 1 to 9.

11. A communication unit for communicating with the outside; A switching unit that switches the power system on the AC side of the power conversion unit; A control unit that controls the opening and closing unit, The communication unit receives an open signal to open the opening / closing unit, The control unit opens the opening / closing unit based on the open signal received by the communication unit. The power conversion system according to any one of claims 1 to 10.

12. A measurement device that functions as the measurement unit of the power conversion system according to any one of claims 1 to 11, The terminal portion is electrically connected to the power conversion unit. Measuring equipment.

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