Power supply system

Abstract

To realize a power supply system that provides a stable supply of power to a distribution board within a home with a simple configuration.SOLUTION: A power supply system 10 according to the present invention includes a connection terminal to which a solar panel 20 and a storage battery 30 are connected, an input terminal connected to a commercial power system, and an output terminal to supply AC power to a distribution board within the home, and is configured to selectively supply power from the commercial power system and power from the solar panel 20 or the storage battery 30 to the distribution board within the home by controlling the relays within the power supply system 10.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power supply system equipped with a solar panel and a storage battery. [Background technology]

[0002] BACKGROUND ART Conventionally, there has been provided a power supply system that includes solar panels and a storage battery, converts DC power generated by the solar panels into AC power and supplies it to a load system in order to save on utility costs during the day, and charges the storage battery with surplus power generated by solar power during the day and supplies that power to a load at night.

[0003] In such a power supply system, when the amount of power generated by the solar panels is low due to cloudy weather or the like, the amount of power used in the home may be greater than the amount of power generated, and there may not be enough surplus power to charge the storage battery with the power generated during the day. Furthermore, even when the power charged in the storage battery is insufficient, it is necessary to provide a stable power supply to important load systems such as refrigerators. To meet this demand, power supply systems that use solar panels and storage batteries to provide a stable power supply to homes have been proposed (see, for example, Patent Documents 1-7).

[0004] For example, the power supply system of Patent Document 4 includes a solar cell array and a storage battery system that charges the power generated by the solar cell array, and the storage battery system is connected to a distribution board and a critical load system within the home, and the power generated by the solar cell array is supplied to the distribution board or critical load system within the home via the storage battery system. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-055059 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-027849 [Patent Document 3] Japanese Patent Application Laid-Open No. 2014-183716 [Patent Document 4] Japanese Patent Application Laid-Open No. 2014-192986 [Patent Document 5] Japanese Patent Application Laid-Open No. 2014-195401 [Patent Document 6] Japanese Patent Application Publication No. 2017-055565 [Patent Document 7] Japanese Patent Application Publication No. 2018-011476 Summary of the Invention [Problem to be solved by the invention]

[0006] The power supply system of Patent Document 4 requires a breaker that is installed in the distribution board between the system power supply and the battery system and that opens in the event of a power outage, and an emergency changeover switch that is installed between the important load system and the distribution board and the battery system and that connects the distribution board and the battery system under normal conditions and connects the battery system and the important load system in the event of a power outage, which results in a complex configuration of the power supply system and poses the problem that the user must switch the changeover switch in the event of a power outage.

[0007] The present invention has been made to solve the above-mentioned problems, and has an object to realize a power supply system with a simple configuration that stably supplies power to a load system within a home. [Means for solving the problem]

[0008] In order to achieve the above object, the power supply system of the present invention includes a solar panel connection terminal connected to a solar panel, a storage battery connection terminal connected to a storage battery, a commercial power input terminal connected to a commercial power grid, an AC power output terminal for supplying AC power to a distribution board in a home, a DC / AC inverter that converts DC current from the solar panel and / or the storage battery into AC current and supplies the AC power output terminal, a first relay provided between an output terminal of the DC / AC inverter and the AC power output terminal, a second relay provided between an output terminal of the first relay and the commercial power input terminal, a detection circuit that detects the current and / or voltage of the commercial power grid, and a controller that controls the voltage and / or current output by the DC / AC inverter and controls the first relay and the second relay, and the controller is configured to control the first relay and the second relay in accordance with the detection result of the detection circuit and the output of the DC / AC inverter.

[0009] In a configuration example of the power supply system according to the present invention, the controller turns the first relay on and the second relay off when the current and / or voltage of the commercial power grid falls below a predetermined value, and turns the first relay off and the second relay on when the output of the DC / AC inverter falls below a predetermined value. The added items are not described here because they overlap with the items described in the latter half of the embodiment. This paragraph corresponds to claim 2.

[0010] An example configuration of the power supply system according to the present invention includes a third relay that is an UVR that is provided between the commercial power input terminal and the AC power output terminal and monitors the output voltage of the DC / AC inverter, and when a hang-up of the power supply system is detected based on the output voltage of the DC / AC inverter, the third relay is turned on and connects the commercial power input terminal to the AC power output terminal.

[0011] In the configuration example of the power supply system according to the present invention, when the hang-up of the power supply system is resolved, the controller resets the third relay to an OFF state. [Effects of the Invention]

[0012] The power supply system of the present invention is equipped with connection terminals for connecting the solar panel and the storage battery, an input terminal for inputting AC power from the commercial power system, and an output terminal for outputting AC power to the load system within the home, and is configured to selectively supply power from the commercial power system and power from the solar panel or the storage battery to the load system within the home by controlling the relay within the power supply system.This makes it possible to realize a power supply system that provides a stable supply of power to the load system within the home with a simple configuration, and a full-load power supply system can be realized. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram showing the configuration of a power supply system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing the configuration of the power supply system according to the first embodiment of the present invention (when solar power generation is performed). [Figure 3] FIG. 3 is a diagram showing the configuration of the power supply system according to the first embodiment of the present invention (when solar power generation is performed). [Figure 4] FIG. 4 is a diagram showing the configuration of a power supply system according to a second embodiment of the present invention (when power is supplied from a commercial power system). [Figure 5] FIG. 5 is a diagram showing the configuration of a power supply system according to a second embodiment of the present invention (when power is supplied from a commercial power system). [Figure 6] FIG. 6 is a diagram showing the configuration of a power supply system according to a third embodiment of the present invention (when a failure occurs in the power supply system). [Figure 7] FIG. 7 is a diagram showing the configuration of a power supply system according to the third embodiment of the present invention (when the power supply system is restored). DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. <Power supply system configuration> FIG. 1 is a diagram showing the configuration of a power supply system according to an embodiment of the present invention.

[0015] The power supply system 10 according to the embodiment of the present invention includes a solar panel connection terminal 104 connected to the solar panel 20, a storage battery connection terminal 105 connected to the storage battery 30, a commercial power input terminal 106 connected to a commercial power system, an AC power output terminal 107 (single-phase three-wire, 100V-N-100V with a midpoint of V0-N-V1) for supplying AC power to a distribution board in a home, and a DC / AC inverter for converting DC current from the solar panel 20 and / or the storage battery 30 into AC current and supplying the AC power output terminal. The power supply system includes a first relay 110, a first relay 111 provided between the output terminal of the DC / AC inverter 110 and an AC power output terminal 107, a second relay 112 provided between the output terminal of the first relay 111 and a commercial power input terminal 106, a detection circuit (CT / VT) 40 that detects the current and / or voltage of the commercial power system, and a controller 101 that controls the AC power output by the DC / AC inverter 110 and also controls the relays (111, 112) and switch 114, etc., in the power supply system.

[0016] The power supply system according to the embodiment of the present invention includes a DC / AC inverter 110 that converts DC current from the solar panel 20 and / or the storage battery 30 into AC current and supplies the AC current to an AC power output terminal. The DC / AC inverter 110 supplies AC power of V0-N-V1 (single-phase, 100V-N-100V) with N as the midpoint to the AC power output terminal 107.

[0017] For example, a typical power supply system for selling low-voltage electricity (output of 10 kW or less) outputs AC power with an output value of 100 V-N-100 V. In this case, if two DC-AC 100 V inverters are connected in series in the DC / AC inverter 110 and the connection point of the two serially connected inverters is set as the midpoint (N) of the AC power, AC power with V0-N-V1 of 100 V-N-100 V with N as the midpoint can be supplied to the AC power output terminals without using a transformer.

[0018] 1, breaker 50, which is placed between the power supply system and the commercial power system, and breaker 60, which is placed between the power supply system and the load system, are breakers for preventing overcurrent and ensuring safety during installation and maintenance. Either an ELB (Earth Leakage Circuit Breaker) or an MCB (Molded Case Circuit Breaker) may be used as the breaker.

[0019] The MPPT 108 and the DC / DC converter 109 have the function of converting the DC power of the solar panel 20 and the storage battery 30 into DC power suitable for input to the DC / AC inverter 110. The MPPT (Maximum Power Point Tracking) 108 can maximize the output power of the solar panel 20.

[0020] The DC / DC converter 109 is a bidirectional inverter that can also convert DC power from the solar panel 20 or the DC / AC inverter 110 into DC power suitable for input to the storage battery 30. This function is used when charging the storage battery 30 with power from the solar panel 20 or the commercial power system.

[0021] The controller 101 is configured to control the voltage and / or current output by the DC / AC inverter 110 and to selectively supply power from the commercial power system and power from the solar panel 20 and the storage battery 30 to the load system (distribution board inside the home) by controlling the relays in the power supply system 10.

[0022] The first relay 111 is provided between the output terminal of the DC / AC inverter 110 and the AC power output terminal 107, and is a relay for supplying the output power of the DC / AC inverter 110 to the load system.

[0023] The second relay 112 is provided between the output terminal of the first relay 111 and the commercial power input terminal 106, and is a relay for supplying power supplied from the commercial power system to the load system.

[0024] The controller 101 is configured to control the first relay 111 and the second relay 112 in accordance with the detection result of the detection circuit 40 and output information of the DC / AC inverter 110. The detection result of the detection circuit 40 is provided via an I / F 103 of the power supply system 10.

[0025] For example, if the detection result of the detection circuit 40 indicates that the current and / or voltage of the commercial power system is equal to or lower than a predetermined value (for example, the voltage is 90 V), the controller 101 turns the first relay 111 to the "ON state" and the second relay 112 to the "OFF state," converts the DC current supplied from the solar panel 20 to AC current, and supplies it to the load system (distribution board in the home) via the AC power output terminal 107. If a power outage or the like occurs in the commercial power system, the detection circuit 40 can detect this and automatically switch the power supply to the load system (distribution board in the home) from the commercial power system to the DC / AC inverter 110.

[0026] At this time, if there is surplus power generated by solar power generation, it can be used to charge the storage battery 30. Even if the solar panel 20 is unable to generate sufficient power, such as at night or in bad weather, the DC power supplied from the storage battery 30 can be converted into AC power and supplied to the load system (distribution panel inside the home).

[0027] On the other hand, when the solar panel 20 cannot generate enough power and the storage battery 30 cannot supply enough power, such as at night or in bad weather, the controller 101 turns the first relay 111 to the "OFF state" and the second relay 112 to the "ON state" to supply power from the commercial power system to the load system (distribution board in the home). This allows for a stable power supply to the load system in the home.

[0028] The power supply system may also include a third relay 113 that is an under voltage relay (UVR) that is provided between the commercial power input terminal and the AC power output terminal and monitors the output voltage of the DC / AC inverter 110.

[0029] The third relay 113 turns to the "ON state" when it detects a hang-up of the power supply device based on the output voltage of the DC / AC inverter 110, and can connect the commercial power input terminal to the AC power output terminal. Therefore, even if a failure occurs in the power supply system and the system goes into a hang-up state, it becomes possible to supply power from the commercial power system to the load system (distribution board inside the home).

[0030] As described above, according to the power supply system 10 of the present embodiment, it is possible to realize a power supply system with a simple configuration that can stably supply power to a distribution board in a home.

[0031] First Embodiment <When power is supplied from solar panels / storage batteries: Figures 2 and 3> 2 and 3 are diagrams showing the configuration of the power supply system according to the first embodiment of the present invention (when solar power generation is performed).

[0032] As shown in FIG. 2, when the detection circuit 40 detects that the current and / or voltage of the commercial power system is equal to or lower than a predetermined value (for example, the voltage is 90 V), the power supply system 10 switches the first relay 111 to the "ON state" and the second relay 112 to the "OFF state," disconnecting the load system from the commercial power system, converting the DC power generated by the solar panel 20 into AC power using the DC / AC inverter 110, and supplying it to the load system (a distribution board inside the home).

[0033] Furthermore, even when the solar panel 20 is unable to generate sufficient power, such as at night or in bad weather, if the storage battery 30 is sufficiently charged, the DC power supplied from the storage battery 30 via the DC / DC converter can be converted into AC power by the DC / AC inverter 110 and supplied to the load system.

[0034] As shown in FIG. 3, if there is surplus power generated by solar power generation, the DC power generated by the solar panel 20 can be converted into AC power and supplied to the load system (distribution panel inside the home), while the surplus power generated by solar power generation can be used to charge the storage battery 30 via a DC / DC converter.

[0035] <Second embodiment> <When power is supplied from a commercial power grid: Figures 4 and 5> At night or in bad weather, when the solar panel 20 is unable to generate sufficient power and the storage battery is not sufficiently charged, the first relay 111 is set to the "OFF state" and the second relay 112 is set to the "ON state," as shown in FIG. 4, so that power can be supplied from the commercial power grid to the load grid. This allows for a stable power supply to the important load grid. In actual equipment, a long relay switching time can cause flickering, so the relay switching time is important. Theoretically, at 50 Hz, switching should be completed within 20 msec, but in practice, it is desirable for switching to be completed within a switching time of about 10 msec.

[0036] In this case, as shown in Fig. 4, the power generated by the solar panel 20 may be charged into the storage battery 30. Alternatively, as shown in Fig. 5, the first relay 111 may be set to the "ON state" so that the power supplied from the commercial power grid is charged into the storage battery 30.

[0037] <Third embodiment> <When the power supply system fails: Figures 6 and 7> If some kind of trouble occurs in the power supply system 10, such as a failure of the controller 101, and the power supply system 10 hangs up and is unable to control the power supply, power cannot be supplied to the load system, and the output voltage of the DC / AC inverter 110, i.e., the voltage between the terminals of the AC power output terminal 107, becomes "0V."

[0038] To prepare for such a case, the power supply system 10 may include a third relay 113 provided between the commercial power input terminal and the AC power output terminal, as shown in Fig. 6. The third relay 113 is a UVR that monitors the output voltage of the DC / AC inverter 110 and turns "ON" if it detects a hang-up in the power supply system.

[0039] The third relay 113 turns to the "ON state" when the output voltage of the DC / AC inverter 110 becomes "0 V" and a hang-up of the power supply system 10 is detected, and the commercial power input terminal 106 can be connected to the AC power output terminal 107. Therefore, even if a failure occurs in the power supply system 10 and the power supply system 10 goes into a hang-up state, it becomes possible to supply power from the commercial power system to the load system (distribution board in the home). Supplying power from the commercial power system to the load system via the power supply system 10 is called "pass-through."

[0040] In this way, regardless of whether it is day or night, if the power supply system 10 hangs up, switching to the commercial power system is automatically performed without human intervention, and power can be supplied from the commercial power system to the load system, so it is possible to avoid a situation in which power cannot be supplied to the load system if the power supply system 10 hangs up.

[0041] Furthermore, as shown in FIG. 7, when the power supply system 10 recovers to a normal state and the hang-up state is resolved, the controller 101 can reset the third relay 113 to the "OFF state," thereby restoring the system to a state in which it can control the supply of power to the load system.

[0042] In this case, if the amount of power supplied by the solar panel 20 and the storage battery 30 is sufficient for the demand of the load system, as described in Figure 2, the first relay 111 is set to the "ON state" and the second relay 112 is set to the "OFF state", and the power supplied by the solar panel 20 and the storage battery 30 is supplied to the load system.

[0043] On the other hand, if the amount of power supplied by the solar panel 20 or the storage battery is insufficient for the demand of the load system, as explained in FIG. 4, the first relay 111 is set to the "OFF state" and the second relay 112 is set to the "ON state" so that the power supplied from the commercial power system can be supplied to the load system. [Explanation of symbols]

[0044] 10...Power supply system, 20...Solar panel, 30...Storage battery, 40...Detection circuit (CT / VT), 50, 60...Breaker.

Claims

1. a solar panel connection terminal to be connected to the solar panel; a battery connection terminal connected to the battery; a commercial power input terminal connected to a commercial power system; an AC power output terminal for supplying AC power to a distribution board in the home; a DC / AC inverter that converts a direct current from the solar panel and / or the storage battery into an alternating current and supplies the alternating current to the AC power output terminal; a first relay provided between an output terminal of the DC / AC inverter and the AC power output terminal; a second relay provided between the output terminal of the first relay and the commercial power input terminal; a detection circuit for detecting a current and / or a voltage of the commercial power system; a controller that controls the voltage and / or current output by the DC / AC inverter and also controls the first relay and the second relay; Equipped with The controller The first relay and the second relay are controlled in accordance with the detection result of the detection circuit and the output of the DC / AC inverter. Power supply system.

2. The controller when the current and / or voltage of the commercial power system becomes equal to or lower than a predetermined value, the first relay is turned on and the second relay is turned off; When the output of the DC / AC inverter becomes equal to or lower than a predetermined value, the first relay is turned off and the second relay is turned on. The power supply system according to claim 1 .

3. a third relay that is an UVR that is provided between the commercial power input terminal and the AC power output terminal and monitors an output voltage of the DC / AC inverter; When a hang-up of the power supply system is detected based on the output voltage of the DC / AC inverter, the third relay is turned on to connect the commercial power input terminal to the AC power output terminal. The power supply system according to claim 1 .

4. The controller When the hang-up of the power supply system is resolved, the third relay is reset to an OFF state. The power supply system according to claim 3 .

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