JP6299514B2 - Power supply system - Google Patents

Description

  The present invention relates to a power supply system that controls power generation of a fuel cell and storage / discharge amount of the storage battery.

  2. Description of the Related Art Conventionally, in a power supply system provided in a house, power from the grid power can be charged in a storage battery, and the power is supplied to the electrical load of the house. Moreover, not only a storage battery but also a power supply system that links a fuel cell or the like is disclosed. In such a power supply system, in order to prevent reverse power flow during combined operation of the storage battery and the fuel cell, the distribution board is divided into two, and the load discharged from the storage battery and the load generated by the fuel cell are separated (for example, patents) Reference 1).

  A distributed power supply system in which a fuel cell and a storage battery are provided in one distribution board is also disclosed. However, attention is focused on realizing more energy-saving and more economical energy management (for example, Patent Document 2). reference).

JP 2014-64351 A JP 2014-50233 A

  The technology described in Patent Document 1 described above is configured so that the reverse power does not occur in hardware, so the configuration of two distribution boards increases the size of the distribution board, increases the number of parts, and manufacturing costs. There is a problem of increase.

  In the technique described in Patent Document 2 described above, when the load is consuming electric power due to discharge from the storage battery and power generation of the fuel cell, a reverse power flow occurs when the load suddenly changes and power consumption is reduced. There is a fear. In addition, in order to prevent reverse power flow, when a fuel cell is stopped urgently, it is necessary to have a specialized contractor work until it returns to the normal state from the emergency stop state. There is a problem that it takes.

  Therefore, the present invention has been made in view of the above-described problems, and even if the power consumption of the electric load suddenly changes and decreases, the power that prevents the fuel cell from stopping while preventing the occurrence of reverse power flow. The purpose is to provide a supply system.

  The present invention employs the following technical means in order to achieve the aforementioned object.

According to the present invention, the storage / discharge amount of the storage battery (33) and the power generation of the fuel cell (15) are controlled in accordance with the amount of power consumption, and the power generation stoppage is controlled. Control means (31) for controlling to be preferentially consumed by the load,
The control means controls so that the storage battery stores electricity when both the fuel cell and the storage battery are discharged to the wiring, and the change amount acquired by the acquisition means is larger than the upper limit value of the storage battery. This is a power supply system characterized by that.

  According to the present invention, the storage battery discharge amount and the fuel cell power generation or power generation stoppage are controlled in accordance with the amount of power consumption, and the storage battery and fuel cell power is supplied to the electrical load rather than the power from the power system. It is controlled so that it is consumed preferentially. As a result, the power storage amount of the storage battery and the power generation amount of the fuel cell are preferentially consumed, and the power consumption from the power system can be suppressed.

  In the present invention, the amount of change in power consumption is acquired by the acquisition means. When both the fuel cell and the storage battery are discharged to the wiring, if the amount of change in power consumption increases, reverse power flow may occur. Therefore, in the present invention, when the amount of change in power consumption is larger than the upper limit value of the response speed of the storage battery, the storage battery is controlled by the control means so as to store power. When the storage battery stores electricity, the power of the wiring is consumed by the electricity storage, so that the power consumption increases. Even if the power consumption changes suddenly and decreases due to this, it is possible to prevent reverse power flow by intentionally increasing the power consumption by storing electricity. Therefore, even when the power consumption suddenly decreases, it is possible to prevent the fuel cell from being stopped urgently while preventing the occurrence of reverse power flow.

  In addition, the code | symbol in the bracket | parenthesis of each above-mentioned means is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

1 is a block diagram showing a simplified power supply system 10. FIG. It is a flowchart which shows the process of control ECU31. It is a graph for demonstrating the variation | change_quantity of power consumption. It is a graph which shows the 1st example of electric power change. It is a graph which shows the 2nd example of electric power change.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. The power supply system 10 is a system capable of supplying supply power supplied from a power supply source power system to an electric load connected to an AC power line L in a building based on a power supply contract. In the power supply system 10 of the present embodiment, one (single) power supply contract is concluded in which the power cost in the midnight time zone, for example, from 24:00 to 7:00, is lower than the power cost in other time zones. doing. An hourly watt hour meter (not shown) is disposed on the AC power line L for introducing purchased power supplied from the power system of the power company into the building.

  As shown in FIG. 1, the power supply system 10 includes, for example, an AC power line L wired in a building that is a house, a power storage unit 11, a solar power generator 12, a residential load 13, a distribution board 14, a fuel cell 15, A power sensor unit 16 is provided. The AC power line L wired in the building is, for example, a single-phase three-wire power line consisting of one neutral line and two voltage lines, and the power from the power system of the power company is divided. It is supplied via the board 14.

  The distribution board 14 is provided with a main breaker 21, a storage battery current sensor 22, and a fuel cell current sensor 23. The main breaker 21 is a breaker with a leakage detection function that regulates the upper limit value of the current flowing through the AC power line L. Moreover, the main breaker 21 is connected to the solar PCS 12a of the solar power generator 12, and also functions as a breaker that regulates the upper limit value of the current flowing from the solar PCS 12a.

  In the distribution board 14, the AC power line L is branched from the power storage unit 11, the fuel cell 15, the home load 13, and the power sensor unit 16 via the main breaker 21. As described above, the AC power line L is connected to the in-house load 13 of various electric devices and can supply power to the in-house load 13.

  The storage battery current sensor 22 and the fuel cell current sensor 23 detect the current of the AC power line L immediately after the main breaker 21. The storage battery current sensor 22 provides the storage unit 11 with information on the detected current. The fuel cell current sensor 23 provides the fuel cell 15 with information on the detected current. The power storage unit 11 calculates a current based on the information given from the storage battery current sensor 22, and gives information related to the calculated current value to the control ECU 31. The power sensor unit 16 detects the power in the distribution board 14 and transmits the detected power amount to each device.

  Next, the solar power generator 12 will be described. The solar power generator 12 is a solar power generation means that generates power using sunlight, and supplies power outside the system to the AC power line L. The solar power generator 12 includes a solar panel 12b and a solar PCS 12a. The solar panel 12b is provided on the roof of a building, for example, and generates power using sunlight. The solar panel 12b supplies the generated solar power to the solar PCS 12a. The sunlight PCS 12a is electrically connected to the AC power line L via the main breaker 21, converts the DC power from the solar panel 12b into AC power, and discharges it to the AC power line L. Although not shown, the solar PCS 12a is connected to a LAN (local area network) and configured to be communicable with each unit.

  Next, the fuel cell 15 will be described. The fuel cell 15 generates electric power through a chemical reaction and can discharge the generated electric power to the wiring. The fuel cell 15 includes a plurality of fuel cells that use hydrogen or methanol as fuel. The power generation voltage of the fuel cell 15 varies depending on the model of the fuel cell 15 and the like. The fuel cell 15 has a fuel cell PCS inside, and is electrically connected to the AC power line L in parallel via the fuel cell PCS.

  The fuel cell PCS converts the DC power from the fuel cell 15 into AC power and discharges it to the AC power line L. Therefore, the fuel cell 15 can discharge the generated DC power to the AC power line L. The fuel cell 15 is communicably connected to other devices by a fuel cell monitoring ECU (not shown) mounted on the fuel cell 15. The fuel cell 15 is connected to the fuel cell current sensor 23, the HEMS monitor 32, and the like, and can exchange information (information transmission) with each other.

  Next, the power storage unit 11 will be described. The power storage unit 11 is installed outside a building, for example, and is also referred to as a power storage device, a power storage system, or an “e-Station”. The power storage unit 11 is electrically connected to the AC power line L. The power storage unit 11 includes a home energy management system (HEMS) monitor 32, a control ECU 31, and a storage battery 33.

  The storage battery 33 is a power storage means capable of storing and discharging electric power, and is an aggregate obtained by combining a plurality of unit batteries made of secondary batteries such as lithium ion batteries. Storage battery 33 has storage battery PCS inside, and is electrically connected in parallel to AC power line L via storage battery PCS.

  The storage battery PCS converts the AC power from the AC power line L into DC power and supplies it to the storage battery 33. The storage battery PCS converts the DC power from the storage battery 33 into AC power and discharges it to the AC power line L. Therefore, the storage battery 33 can charge the AC power from the AC power line L, or discharge the stored DC power to the AC power line L. As described above, the storage battery 33 can store the solar power generated by the solar power generator 12 and the supply power supplied from the power system, and can discharge the stored power to the AC power line L.

  The storage battery 33 is communicably connected to other devices by a storage battery monitoring ECU (not shown) mounted on the storage battery 33. The storage battery 33 is connected to the storage battery current sensor 22, the control ECU 31, the HEMS monitor 32, and the like via a LAN, and can exchange information (information transmission) with each other.

  The storage battery 33 also functions as a power storage control unit that controls charging and discharging. The power storage unit 11 includes a relay (not shown) therein, and can switch the connection state between the AC power line L and the storage battery 33 between the connection state and the disconnection state by switching the connection state of the relay. Therefore, when the AC power line L and the storage battery 33 are in a disconnected state, the discharge from the storage battery 33 to the AC power line L is stopped.

  Next, the HEMS monitor (storage battery operating unit) 32 will be described. The HEMS monitor 32 functions as notifying means for displaying the state of each part and operating means for operating each part. The HEMS monitor 32 is, for example, remote operation means (so-called remote control) disposed in a building. As described above, the HEMS monitor 32 is LAN-connected to each unit and can communicate with the external center server 40. The HEMS monitor 32 includes a display unit corresponding to notification means and an operation switch for operating each unit. On the display unit, for example, the storage state of the storage battery 33, the power generation amount of the solar cell, the power generation state of the fuel cell 15, the amount of power used by the home load 13 and the like are displayed. Further, by operating the operation switch, it is possible to instruct the storage battery 33 to store power and make various settings. The HEMS monitor 32 can acquire predetermined information by communicating with the center server 40.

  Next, the control ECU 31 will be described. Although not shown in the figure, the control ECU 31 includes an input circuit to which a communication signal and a detection signal from a power sensor unit and the like are input, a microcomputer that executes various calculations using signals from the input circuit, and a microcomputer. And an output circuit for outputting a control signal for controlling each part based on the calculation by the above. The microcomputer has a ROM (Read-Only Memory: abbreviated ROM), a ram (Random Access Memory: abbreviated RAM), etc. as storage means for storing various data, calculation results, and the like. An updatable control program is stored. The control ECU 31 executes a control program stored in the storage means and executes each process described later. As with the HEMS monitor 32, the control ECU 31 is LAN-connected to each part. The control ECU 31 gives a control command to each unit so that each unit operates in accordance with an instruction input by the operation switch of the HEMS monitor 32. In addition, the control ECU 31 controls the display unit of the HEMS monitor 32 so as to display information according to the state of each unit.

  Each of the storage battery 33 and the fuel cell 15 has an upper limit value of the response speed that can follow the fluctuation of the power consumption in the house. This upper limit value is stored in the ROM or RAM of the control ECU 31 as the characteristic value ab of the storage battery 33 and the characteristic value as of the fuel cell 15 at the time of manufacture. In the present embodiment, the characteristic value ab of the storage battery 33 is larger than the characteristic value as of the fuel cell 15. Therefore, since the large upper limit value when the upper limit value of the storage battery 33 is compared with the upper limit value of the fuel cell 15 is the characteristic value ab of the storage battery 33 in this embodiment, the maximum upper limit value is the characteristic value ab. As a result, the storage battery 33 is easier to control the output power than the fuel cell 15 and can easily follow fluctuations in power consumption in the house.

  For example, the control ECU 31 operates the power storage unit 11 in the midnight time zone when power is inexpensive, and causes the storage battery 33 to store power. As a result, a new amount of electricity is added to the storage battery 33. The storage battery 33 is charged up to, for example, a full charge amount (limit charge amount) that is an upper limit amount to be stored in the midnight time zone.

  Further, the control ECU 31 controls the storage / discharge amount of the storage battery 33 and the power generation amount of the fuel cell 15 according to the amount of power consumption of the home load 13. Therefore, the control ECU 31 controls power generation or power generation stop of the fuel cell 15. And control ECU31 is controlled so that the electric power of the storage battery 33 and the fuel cell 15 is preferentially consumed by the residential load 13 rather than the electric power from an electric power grid | system. As a result, midnight power can be used effectively. Furthermore, when the solar power generator 12 is generating electric power, the control ECU 31 performs control so that the electric power generated by the solar light is used most preferentially. This makes it possible to effectively use the photovoltaic power generation with the lowest cost.

  Next, control of the control ECU 31 will be described with reference to FIG. The flow shown in FIG. 2 is a process that is repeatedly executed in a short time in a state where the storage battery 33 and the fuel cell 15 are discharged.

  In step S1, the characteristic value ab of the storage battery 33 is read, and the process proceeds to step S2. The characteristic value is stored in advance in the ROM of the control ECU 31.

  In step S2, the current power consumption in the house is acquired from the power sensor unit 16, and the process proceeds to step S3. The acquired power consumption is stored in the RAM of the control ECU 31 together with the acquired time.

  In step S3, the current power consumption change amount a is calculated, and the process proceeds to step S4. Here, the change amount a will be described with reference to FIG. The amount of change is a value in which the power consumption changes per unit time. Therefore, for example, as shown in FIG. 3, the amount of change a1 when the power consumption decreases by y1 during time t1 is y1 / t1. Similarly, the amount of change a2 when the power consumption decreases by y2 during time t2 is y2 / t2. Therefore, in step S3, the difference between the previous power consumption stored this time and the current power consumption is obtained using the value obtained by the control ECU 31 periodically, and divided by the measurement cycle. Is used to calculate the current change amount a.

  In step S4, it is determined whether or not the change amount a is larger than the characteristic value ab of the storage battery 33. If the change amount a is larger, the process proceeds to step S5. Since the characteristic value ab of the storage battery 33 is larger than the characteristic value as of the fuel cell 15 and the maximum upper limit value, when the amount of change a is larger than the maximum upper limit value, the voltage control of the storage battery 33 changes the power consumption in the house. I cannot follow.

  In step S5, since the change amount a is larger than the characteristic value ab of the storage battery 33, the discharge mode in which the storage battery 33 is discharged is changed to the storage mode for storing power, and this flow ends. As described above, the voltage control of the storage battery 33 cannot follow the fluctuations in the power consumption in the house. Therefore, the fuel cell 15 needs to be urgently stopped to prevent the reverse power flow from occurring. Therefore, in order to increase power consumption in the home, the storage battery 33 is switched to the power storage mode. As a result, the power consumption increases due to the storage of the storage battery 33, so that a sudden drop in power consumption can be suppressed. Therefore, the emergency stop of the fuel cell 15 can be prevented.

  Next, the power change when the power consumption in the home fluctuates will be described with reference to FIGS. 4 and 5. FIG. 4 shows three waveforms, each of which shows the power consumption of the home load 13, the discharge power of the storage battery 33, and the power generation of the fuel cell 15. Therefore, the fuel cell 15 and the storage battery 33 are discharged to the wiring. The fuel cell 15 has a constant output voltage and is unlikely to fluctuate. When the power consumption in the home fluctuates, the discharge power of the storage battery 33 is controlled so that reverse power flow does not occur.

  For example, when the power consumption decreases at time t41 in FIG. 4, control is performed so that the discharge power of the storage battery 33 decreases at time t42 so as to follow the power consumption. The amount of change in decrease from time t41 is small and a gradual change. Therefore, since the change amount a is smaller than the characteristic value ab of the storage battery 33, it can be followed by controlling the discharge power of the storage battery 33.

  Further, when the power consumption increases at time t43, control is performed so that the discharge power of the storage battery 33 increases from time t44 so as to follow similarly. This is also a gradual change and can be followed. As a result, the power consumption in the house can be covered by the generated power of the fuel cell 15 and the discharged power of the storage battery 33.

  Similarly, FIG. 5 shows three waveforms, each showing the power consumption of the home load 13, the discharge power of the storage battery 33, and the power generation of the fuel cell 15. When the power consumption decreases at time t51 in FIG. 5, control is performed so that the discharge power of the storage battery 33 decreases at time t52 so as to follow the power consumption. However, the amount of change from the time t51 is large and is a sudden decrease. Therefore, the change amount a is larger than the characteristic value ab of the storage battery 33, and it is difficult to follow even if the discharge power of the storage battery 33 is controlled. Therefore, at time t52, control is performed such that the storage battery 33 is switched from the discharge mode to the storage mode. As a result, the discharge power of the storage battery 33 disappears, and instead, the power consumption increases due to the storage. Thereby, it is possible to prevent the sum of the discharged power of the storage battery 33 and the generated power of the fuel cell 15 from exceeding the power consumption. Therefore, it is possible to prevent the fuel cell 15 from being urgently stopped while preventing reverse power flow.

  As described above, the power supply system 10 of the present embodiment acquires the amount of change in power consumption by the control ECU 31 that is an acquisition unit. When both the fuel cell 15 and the storage battery 33 are discharged to the wiring, if the amount of change in power consumption increases, reverse power flow may occur. Therefore, in the present embodiment, when the amount of change in power consumption is larger than the characteristic value ab, which is the upper limit value of the response speed of the storage battery 33, the control ECU 31 controls the storage battery 33 to store power. When the storage battery 33 stores electricity, the power of the wiring is consumed by the electricity storage, so that the power consumption increases. Even if the power consumption changes suddenly and decreases due to this, it is possible to prevent reverse power flow by intentionally increasing the power consumption by storing electricity. Therefore, even if the power consumption suddenly decreases, it is possible to suppress the emergency stop of the fuel cell 15 while preventing the occurrence of reverse power flow.

  In other words, conventionally, when the load suddenly changes, the discharge power of the storage battery 33 follows the load, whereas the fuel cell 15 has a slow follow-up speed. Therefore, it is possible to achieve both the discharge of the storage battery 33 and the power generation from the fuel cell 15 with a single distribution board 14, and no reverse power flow will occur even if the power consumption in the house suddenly fluctuates and the equipment will not be urgently stopped. It was rare. In the present embodiment, a mode in which a sudden change in the home load 13 in a short cycle is detected and switched to the power storage mode, whereby the fuel cell 15 is urgently stopped, for example, a reverse power relay (RPR) is disconnected and calls a serviceman. It can be avoided from becoming a state.

  In the present embodiment, the upper limit value of the storage battery 33 and the upper limit value of the fuel cell 15 are compared, the larger upper limit value is set as the maximum upper limit value, and the amount of change in power consumption is greater than the characteristic value ab, which is the maximum upper limit value. When it is larger, the control ECU 31 controls the storage battery 33 so as to store power. As a result, even if there are a plurality of devices that are discharged on the wiring, it is possible to switch between storage and discharge of the storage battery 33 by determining whether or not the change in power consumption can be followed.

  Furthermore, in the present embodiment, the upper limit value stored in the control ECU 31 is set when the power supply system 10 is initially set. Since the upper limit value is a value that does not change with the unique value of the product, the upper limit value can be reliably set by being set at the time of initial setting.

  In the present embodiment, the control ECU 31 functions as a communication unit that communicates with the outside, and can communicate with the center server 40. Therefore, the upper limit value stored in the control ECU 31 may be acquired from the center server 40 when the power supply system 10 is initially set. Thereby, for example, the characteristic value can be acquired from the product number of each device connected to the control ECU 31. This eliminates mistakes compared to the case where the user manually sets, and can be easily set. Further, it is effective at the time of resetting such as when the storage battery 33 connected to the power supply system 10 is replaced or when the setting is initialized.

(Other embodiments)
The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  The structure of the said embodiment is an illustration to the last, Comprising: The scope of the present invention is not limited to the range of these description. The scope of the present invention is indicated by the description of the scope of claims, and further includes meanings equivalent to the description of the scope of claims and all modifications within the scope.

  In the first embodiment described above, only one storage battery 33 is provided, but the number of storage batteries 33 is not limited to one, and a plurality of storage batteries 33 may be provided. In this case, if there is a characteristic value in which a plurality of storage batteries 33 are collectively regarded as one storage battery 33, it is preferable to use the characteristic value.

  In the first embodiment described above, the control ECU 31 calculates the amount of change, and the control ECU 31 functions as an acquiring unit by acquiring the calculated amount of change. However, the present invention is not limited to such a configuration. The control ECU 31 may acquire a value calculated by another arithmetic device other than the control ECU 31 through communication or the like.

  In the first embodiment described above, the storage battery 33 is fully charged during the midnight time period, but the storage battery 33 is not limited to the full charge, and may be controlled to charge the required amount of time excluding the midnight time period. . For example, the control device predicts the weather for energy saving and low running cost, predicts the amount of solar power generation in the daytime based on the weather forecast, etc. You may make it determine the estimated electrical storage amount of the late-night charge time zone.

  In the first embodiment described above, the building is a house, but the present invention is not limited to this. For example, the building may be a store, a factory, a warehouse, or the like.

  In the first embodiment described above, the specific time zone is a midnight time zone (a time zone from 24:00 to 7 o'clock), but is not limited to such a time zone, and is appropriately changed according to the power supply contract. Is.

  In the first embodiment described above, the solar power generator 12 is included. However, the solar power generator 12 may be replaced with a wind power generator, or these power generators may not be included. .

  In the first embodiment described above, the power storage unit 11 is configured to be fixed outside the building, for example, but is not limited to such a configuration. Storage battery 33 may be, for example, a plug hybrid (PHV) vehicle equipped with an in-vehicle storage battery, or may be an electric vehicle. Moreover, if it is a vehicle carrying the storage battery 33, it will not be limited to what uses the electric power stored in the storage battery 33 for the drive of a vehicle. Such a vehicle can be connected to the wiring, and the in-vehicle storage battery can be controlled in the same manner as the storage battery 33 of the first embodiment.

10 ... Power supply system 13 ... Home load (electric load)
DESCRIPTION OF SYMBOLS 14 ... Distribution board 15 ... Fuel cell 22 ... Current sensor for storage batteries 23 ... Current sensor for fuel cells 31 ... Control ECU (memory | storage means, acquisition means, control means, communication means)
32 ... HEMS monitor 33 ... Storage battery 40 ... Center server

Claims (5)

A power supply system (10) capable of supplying power supplied to a building from a power supply source power system based on a power supply contract to an electrical load (13) connected to the wiring of the building,
A storage battery (33) connected to the wiring and capable of storing the supplied power supplied from the power system and capable of discharging the stored power to the wiring;
A fuel cell (15) capable of generating electric power by chemical reaction and discharging the generated electric power to the wiring;
Storage means (31) in which the upper limit value of the response speed of the electric power of the storage battery is stored;
Acquisition means (31) for acquiring a change amount per unit time when power consumption in the wiring decreases;
According to the amount of power consumption, the storage / discharge amount of the storage battery and the power generation amount of the fuel cell are controlled, and the power of the storage battery and the fuel cell is prioritized by the electric load over the power from the power system. Control means (31) for controlling to be consumed by
When the change amount acquired by the acquisition unit is larger than the upper limit value of the storage battery when both the fuel cell and the storage battery are discharged to the wiring, the control unit Is controlled so as to store electricity. The storage means stores an upper limit value of the response speed of the power of the fuel cell together with an upper limit value of the storage battery,
Comparing the upper limit value of the storage battery and the upper limit value of the fuel cell, the value of a large upper limit value as the maximum upper limit value,
When the change amount acquired by the acquisition unit is larger than the maximum upper limit when both of the fuel cell and the storage battery are discharged to the wiring, the control unit The power supply system according to claim 1, wherein the power supply is controlled to be stored.   The power supply system according to claim 1, wherein the upper limit value stored in the storage unit is set at the time of initial setting of the power supply system. A communication means (31) for communicating with the outside;
The said upper limit value memorize | stored in the said memory | storage means is acquired and set from the outside by the said communication means at the time of the initial setting of the said electric power supply system, The setting of any one of Claims 1-3 characterized by the above-mentioned. Power supply system.   The acquisition means acquires the amount of change periodically by acquiring the amount of power consumption and dividing the difference between the previous power consumption amount and the current power consumption by the measurement period. The power supply system according to any one of 1 to 4.

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