Power generation control device and power generation control program

Abstract

To make a determination as to follow a load or maintain the status quo in order to achieve optimal primary energy consumption efficiency in a case where a prescribed difference is generated between a power load and the current output of generated power.SOLUTION: In a case where, over the range of a generated power output, a relation with respect to the quantity of used gas does not have a stable characteristic (direct proportional relation having a positive inclination) such as that around a rating (e.g. 400 W in FIG. 4(A) and (B)) but follows a load, primary energy may be increased. In order to avoid such a situation, the necessity to follow the load is determined on the basis of resultant values (following primary energy A, current primary energy B, and sales primary energy C) of respective communication intervals. Accordingly, power generation control suitable for a characteristic of a generated power output-the quantity of used gas can be performed not only around the rating, but in the entire power generation range.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a power generation control device for a distributed power generation facility, and more particularly to a power generation control device and a power generation control program for controlling power generation output in accordance with the power load in a household fuel cell cogeneration system, which is an example of a distributed power generation facility. [Background technology]

[0002] A conventional power generation control method for fuel cell systems is load following operation control, which changes the power generation output in accordance with the power load. By changing the power generation output to follow changes in the load, it is possible to minimize excess or deficiency in the amount of power generated relative to the power load.

[0003] As a prior document regarding follow-up operation, Patent Document 1 describes a method and system for controlling the operation of a fuel cell using power load follow-up, which can quickly follow load fluctuations by using feedforward control when the load fluctuations are large during fuel cell operation.

[0004] Patent Document 1 describes that in a fuel cell, the actual power generation output is Pac(n), the target power generation output is Pac(n+1), and the difference between the actual power generation output Pac(n) and the target power generation output Pac(n+1) is ΔP, and when a certain threshold value P1 is set, feedback control is performed when the absolute value of ΔP is equal to or less than P1, and feedforward control is performed when the absolute value of ΔP is greater than P1.

[0005] Furthermore, Patent Document 2, a prior document that describes efficient load-following operation, describes a household cogeneration system that is provided with a power load processing means that calculates and stores deviations in sampled power load values ​​at predetermined time intervals, an operation pattern provisional determination means that calculates the power generation output, power generation efficiency, heat recovery rate, amount of purchased power, and amount of heat recovered when the fuel cell is operated in load-following mode based on the power load and power load deviation read out under predetermined conditions, and provisionally determines the start and stop times of the fuel cell, an energy consumption amount calculation means that calculates the amount of energy consumed in the provisionally determined operation pattern, and an operation pattern selection means that selects an operation pattern that minimizes energy consumption. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-233439 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-030211 Summary of the Invention [Problem to be solved by the invention]

[0007] The relationship between the amount of gas used, which is the energy source for generating electricity in a fuel cell, and the power output is theoretically a linear proportional relationship (positive slope) in which the amount of gas used increases as the power output increases.

[0008] Here, when the energy source for generating electricity in the fuel cell is gas, the amount of primary energy used is calculated using the following formula.

[0009] Primary energy = (amount of gas used to generate electricity from fuel cells × gas calorific value) + (amount of purchased electricity × primary energy conversion coefficient)

[0010] If the relationship between power generation output and gas consumption is a theoretically linear proportional relationship, then continuous tracking operation can result in a reduction in primary energy consumption.

[0011] However, the relationship between power generation output and gas consumption does not necessarily maintain a linear proportional relationship. In extreme cases, a positive correlation and a negative correlation may coexist.

[0012] In a region where the relationship between power generation output and gas consumption has a negative correlation slope, increasing power generation output may reduce gas consumption.

[0013] That is, from the perspective of primary energy, depending on the current power load and the situation of the power load increasing or decreasing from the current power load, there are cases where primary energy consumption can be reduced by not following the load.

[0014] For example, a power generator has a rating (400W or 700W, etc.) and is usually designed to generate maximum capacity (including fuel consumption) at this rating. In other ranges (e.g., 40W to 200W), the relationship between power output and gas consumption is not directly proportional and may exhibit nonlinear characteristics. In such unstable ranges, adjusting the amount of power generated to follow the required power load may actually worsen fuel consumption (increase gas consumption).

[0015] As an example, as shown in FIG. 4(A), assume that the load at a certain time is 40 W and the power generation device is also generating 40 W.

[0016] Assume that the load at the next time is 80W.

[0017] In this case, if the power generation output is changed to 80W to follow the load, gas consumption will increase.

[0018] On the other hand, if the power generation output is maintained at 40W without load following, the amount of gas used will not change, but the amount of electricity purchased from commercial power sources will increase by 40W.

[0019] When following load or maintaining power generation output, the primary energy consumption may differ depending on the current power generation characteristics shown in Figure 4(A) or the characteristics shown in Figures 4(A) and (B), etc.

[0020] The object of the present invention is to provide a power generation control device and a power generation control program that, when a predetermined difference occurs between the power load and the current power generation output, can determine whether to follow the load or maintain the status quo so as to achieve optimal primary energy consumption efficiency. [Means for solving the problem]

[0021] The power generation control device of the present invention is a power generation control device that controls the operation of a power generation device that is grid-connected to a commercial power source, and has a basic control unit that adjusts the power generation amount of the power generation device in accordance with increases or decreases in load so as to maintain the output of the commercial power source at a predetermined value, and a judgment unit that, when a difference occurs between the load power requiring the power generation amount of the power generation device and the current power generation output, selectively uses a first usage amount, which is the amount of primary energy usage when the power generation amount is adjusted to match the difference based on the control of the basic control unit, a second usage amount, which is the amount of primary energy usage at the current power generation output, and a third usage amount, which is the amount of primary energy usage when the difference is obtained by using electricity from the commercial power source.

[0022] In the present invention, when the required load power is equal to or greater than the current power generation output, the determination unit compares the first usage amount with the total value of the second usage amount and the third usage amount, and when the first usage amount is equal to or greater than the total value, maintains the current power generation output, and when the first usage amount is less than the total value, causes the power generation output to follow the required power load based on the control of the basic control unit.

[0023] In the present invention, when the determination unit determines that the required load power is less than the current power generation output, the determination unit compares the first usage amount with the second usage amount. If the first usage amount is greater than or equal to the second usage amount, the current power generation output is maintained. If the first usage amount is less than the second usage amount, the power generation output is made to follow the required load power based on the control of the basic control unit.

[0024] In the present invention, when the determination unit determines not to follow the power generation output by the basic control unit and to maintain the current power generation output, surplus power is consumed by the internal power consumption equipment constituting the power generation device. When reverse power flow occurs even with the consumption by the internal power consumption equipment, the power generation output is made to follow the basic control unit.

[0025] The power generation control program according to the present invention causes a computer to operate as the above-described power generation control device.

[0026] According to the present invention, when there is a difference between the power load required for the power generation amount of the power generation device and the current power generation output, the first usage amount, which is the amount of primary energy when the difference is made to follow the power generation amount based on the control of the basic control unit, the second usage amount, which is the amount of primary energy in the current power generation output, and the third usage amount, which is the amount of primary energy when the difference is supplied with power from a commercial power source, are selectively used to determine whether to execute the following of the power generation output by the basic control unit. When a predetermined difference occurs between the power load and the current power generation output, it is possible to determine whether to follow the load or maintain the current state so as to achieve an optimal primary energy consumption efficiency.

[0027] For example, defining the primary energy of the gas usage amount when following the load as A, the primary energy of the gas usage amount at the current power generation output as B, and the primary energy of (power load - current power generation output) as C, and obtaining the power load. When it is determined that the power load required for the power generation amount of the power generation device is greater than or equal to the current power generation power, if A ≥ B + C, the current power generation output is maintained, and if A < B + C, the power generation output is changed (followed) to match the power load.

[0028] Also, when the power load is acquired and it is determined that the power load required by the power generation device is less than the current power generation power, if A≥B, the current power generation output is maintained, and if A<B, the power generation output is changed (followed) to match the power load.

Advantages of the Invention

[0029] As described above, according to the present invention, when a predetermined difference occurs between the power load and the current power generation output, it is possible to determine whether to follow the load or maintain the current state so as to achieve the optimum consumption efficiency of primary energy.

Brief Description of the Drawings

[0030] [Figure 1] It is a schematic diagram of a cogeneration device according to the present embodiment and a house in which the cogeneration device is installed (when power information is acquired by a wireless method). [Figure 2] It is a control block diagram of a controller of a cogeneration device according to the present embodiment. [Figure 3] It is a functional block diagram specialized for a power generation control function in a controller of a cogeneration device according to the present embodiment. [Figure 4] (A) and (B) are power generation output - gas consumption characteristic diagrams of different cogeneration devices applicable to the present embodiment, respectively. [Figure 5] It is a flowchart showing a power generation control routine of a cogeneration device according to the present embodiment. [Figure 6] It is a flowchart showing a power generation control routine of a cogeneration device according to Modification 1. [Figure 7] It is a schematic diagram of a cogeneration device according to Modification 3 and a house in which the cogeneration device is installed (when power information is acquired by a wired method).

Embodiments for Carrying Out the Invention

[0031] 1 shows a schematic diagram of a household fuel cell cogeneration system (hereinafter, in this embodiment, simply referred to as "cogeneration system 10") as an example of a distributed power generation facility according to this embodiment. The cogeneration system 10 in FIG. 1 is configured to obtain power information wirelessly.

[0032] As shown in Fig. 1, the cogeneration system 10 is a system in which a tank unit and a fuel cell unit are installed side by side. Note that "side by side" does not necessarily mean that they are physically adjacent to each other, but rather that they are interconnected. In other words, the tank unit and the fuel cell unit may be installed separately and connected by piping, electrical wiring, etc.

[0033] The cogeneration system 10 is installed along the outer wall of the house 12, and workers go to the site to carry out the installation work.

[0034] FIG. 1 shows a state in which the installation work has been completed, the test run has been completed, and the system is ready for steady operation in cooperation with various facilities (electrical equipment, hot water supply facilities, etc.) in the house 12.

[0035] Although not shown, the cogeneration system 10 includes a hot module, a power conditioner, an exhaust heat recovery device, a heat storage tank, a radiator, a heat exchanger, etc., each of which is controlled by the controller 14 in cooperation with each other via a hot water supply-related control unit 27 and a power generation-related control unit 29 shown in FIG. 2.

[0036] The hot module extracts hydrogen in a fuel processor, supplies the extracted hydrogen to a fuel cell stack, and generates DC power using oxygen in the air.

[0037] The power conditioner converts the generated DC power into AC power and supplies it to the house.

[0038] The exhaust heat recovery device recovers heat from the exhaust gas generated by power generation.

[0039] The heat storage tank can store the heat recovered via the heat medium at a high temperature, and the stored heat is used to supply hot water.

[0040] The radiator dissipates heat and cools the heat transfer medium, but the radiator is not essential.

[0041] The heat exchanger uses the high-temperature heat medium from the heat medium tank to heat the tap water. The heat exchanger is not essential.

[0042] The cogeneration system 10 can also send the generated power to a heat source machine 16 via a power line 15. The heat source machine 16 further heats the hot water heated by the cogeneration system 10 by burning city gas (e.g., 13A) as needed and supplies the water to the house 12.

[0043] As shown in FIG. 2, the controller 14 includes a microcomputer 28 that is configured from a CPU 18, a RAM 20, a ROM 22, an I / O 24, and a bus 26 such as a data bus or a control bus that connects these components.

[0044] A hot water supply related control section 27 and a power generation related control section 29 are connected to the I / O 24, and operations relating to hot water supply and power generation are controlled by the controller 14.

[0045] In addition, a large-scale storage device 30 is connected to the I / O 24, which stores processing programs related to power generation and hot water supply executed by the controller 14, as well as historical information based on power generation (for example, in this embodiment, communication interval adjustment information, etc.).

[0046] Furthermore, a remote control 32 is connected to the I / O 24. The remote control 32 is installed inside the house 12 in which the cogeneration system 10 is to be installed, and has functions such as allowing a user to input commands regarding the cogeneration system 10 (and the heat source machine 16) and displaying the status of the cogeneration system 10.

[0047] (Configuration of distributed power sources) As shown in FIG. 1, in the distributed power supply according to this embodiment, a commercial power source 34 to which power is supplied via a power line 38 and power generated by a cogeneration system 10 are used as power sources for a house 12.

[0048] The distribution board 40 is provided with a service breaker 42, an earth leakage breaker 46, and a safety breaker 48 in this order from the upstream side.

[0049] The service breaker 42 is a circuit breaker for determining the contract capacity, but may not be installed.

[0050] The earth leakage breaker 46 is a circuit breaker that quickly detects and cuts off leakage current in the internal wiring or electrical equipment of the house 12, thereby preventing electrical accidents.

[0051] The safety breaker 48 is attached to each branch circuit that transmits power from the distribution board 40 to each point of use in the house 12, and is a circuit breaker that automatically protects the circuit when it detects a short circuit caused by an electrical equipment failure or when power usage above a certain level is detected.

[0052] Here, the electricity generated by the cogeneration system 10 is merged with the commercial power source 34 via a dedicated safety breaker 48A installed in the distribution board 40, and can be used as a power source for electrical equipment inside the house 12.

[0053] Although not shown in the figure, the cogeneration system 10 is provided with a power line dedicated to use in the event of a power outage from the commercial power source 34, so that in a situation where power is not supplied from the commercial power source 34 due to a power outage, the power generated by the cogeneration system 10 can be supplied via a dedicated power outage outlet installed in part of the house 12.

[0054] Here, the controller 14 of the cogeneration system 10 acquires power information such as the current flowing through the power line and controls the amount of power generated in accordance with the load power based on the acquired power information in order to follow and control the power generation in accordance with the ever-changing power consumption in the house 12. This control of power generation in accordance with the load power is called load following control.

[0055] (Wireless power information acquisition configuration) 1, the commercial power supply 34 is connected to a smart meter 36. The smart meter 36 measures power information such as the current, power, and power consumption of the commercial power supply 34, and can transmit the measured information to a specific communication destination via communication paths A, B, and C.

[0056] That is, route A is a communication path connecting the smart meter 36 and the electric power company, route B is a communication path connecting the smart meter 36 and equipment installed in the house 12 (for example, the controller if a HEMS is installed), and route C is a communication path for providing data acquired by the electric power company via route A to a third party (such as a retail electricity supplier).

[0057] A power line 38 output from the smart meter 36 is wired to a distribution board 40 installed in the house 12 .

[0058] In the wireless system, the interval for obtaining power information from the smart meter 36 via the communication path of Route B is set to once every 30 seconds as a standard. This interval allows for control that roughly tracks the ever-changing power usage in the house 12 and approximates load transitions without violating various standards for wireless communication.

[0059] Here, the load following control described above contributes to reducing primary energy consumption, based on the premise that the relationship between the output from power generation (power generation output) and the amount of city gas (hereinafter simply referred to as gas) used for power generation is directly proportional (the larger the power generation output, the greater the amount of gas used).

[0060] However, the relationship between power generation output and gas consumption does not necessarily maintain a linear proportional relationship.

[0061] 4(A) and 4(B) are graphs showing the power generation output vs. gas usage amount characteristics of different cogeneration systems 10 with the same specifications (for example, rated power of 400 W).

[0062] The slopes of the *1 portions shown in Figures 4(A) and 4(B) are different. It can be seen that the slope in the 100W range is steeper than the slope in the 200W range. This means that when increasing power generation in the 100W range, more gas is used than in the 200W range. In some cases, the primary energy of the gas used in load following in the 100W range is greater than the primary energy of the power purchased from the commercial power source 34 (purchased power). This can also occur with different specifications (see the *2 portion between Figures 4(A) and 4(B)).

[0063] Also, in a comparison between Figure 4(A) and Figure 4(B), in the *3 part, there are cases where the gas consumption, which increases the power generation output, increases (Figure 4(A)), and cases where it decreases (Figure 4(B)).

[0064] That is, from the perspective of primary energy, depending on the current power load and the situation of the power load increasing or decreasing from the current power load, there are cases where primary energy consumption can be reduced by not following the load.

[0065] Therefore, in this embodiment, the device to be controlled (power generation control) is controlled by comparing the current power generation with the load power (required power load) required for consumption by the load, and taking into consideration the current primary energy obtained by calculation, the partial energy during tracking, and the primary energy during power purchase, and determining whether it is better to maintain the current power generation output and purchase power from the commercial power source 34, or to make the power generation output follow the load so that the power generation output matches the power load.

[0066] 3 is a functional block diagram for power generation control in the controller 14 of the cogeneration system 10. Each block in this functional block diagram is classified by function, and in this embodiment, the CPU 18 operates based on a communication interval adjustment program stored in the ROM 22, and the control is executed as software control. Note that the operation programs shown in some or all of the functional blocks may be incorporated into an IC chip such as an ASIC and run on the chip.

[0067] 3, the wireless communication unit 50 establishes a communication protocol for acquiring power information via the communication path of Route B of the smart meter 36. The wireless communication unit 50 establishes the communication protocol at a predetermined communication interval (in this embodiment, the default communication interval is once every 30 seconds).

[0068] The wireless communication unit 50 is connected to the power information acquisition unit 52. When a communication protocol is established (successfully) in the wireless communication unit 50, the power information acquisition unit 52 acquires current power information from the smart meter 36 via the communication path of Route B.

[0069] The power information acquisition unit 52 is connected to a required power load calculation unit 54, and calculates a required power load Pr based on the acquired power information. The calculation result of the required power load calculation unit 54 is sent to a situation comparison unit 56.

[0070] The status comparison unit 56 reads the current generated power Pg from the current generated power acquisition unit 58 every time the wireless communication unit 50 acquires power information.

[0071] In the first comparison, the situation comparison unit 56 compares the current generated power Pg with the required power load Pr. This first comparison determines whether the required power load Pr is insufficient or in excess of the current generated power Pg.

[0072] On the other hand, the required power load calculation unit 54 is connected to the load following gas usage acquisition unit 60 and the power purchase energy calculation unit 62, and the calculation result (required power load Pr) is sent to the load following gas usage acquisition unit 60 and the power purchase energy calculation unit 62.

[0073] (Specifying the follow-up primary energy A) The load-following primary energy A is the primary energy of the gas consumption when load-following.

[0074] The load following gas usage acquisition unit 60 is connected to the power generation output-gas usage table memory 64, and reads out the power generation output-gas usage characteristics (for example, Figure 4(A) or Figure 4(B)), which are characteristics unique to the cogeneration device 10. The load following gas usage acquisition unit 60 acquires the gas usage amount at the required power load Pr (gas usage amount at load following) based on the read characteristic diagram, and sends it to the load following primary energy calculation unit 66 .

[0075] The follow-up primary energy calculation unit 66 calculates the follow-up primary energy A by integrating it with the gas calorific value, and sends it to the situation comparison unit 56.

[0076] (Currently identifying primary energy B) Current primary energy B is the primary energy of gas consumption at the current power generation output.

[0077] Here, the current generated power acquisition unit 58 is connected to the current gas usage amount acquisition unit 68 and sends the current generated power Pg to the current gas usage amount acquisition unit 68.

[0078] The current gas usage acquisition unit 68 is connected to the power generation output-gas usage table memory 64, and reads out the power generation output-gas usage characteristics (for example, Figure 4(A) or Figure 4(B)), which are characteristics unique to the cogeneration device 10.

[0079] The current gas usage amount obtaining unit 68 obtains the gas usage amount (current gas usage amount) for the current power generation Pg based on the read characteristic diagram, and sends it to the current primary energy calculation unit 70.

[0080] The current primary energy calculation unit 70 calculates the current primary energy B by integrating it with the gas calorific value, and sends it to the situation comparison unit 56.

[0081] (Identification of purchased primary energy C) Purchased primary energy C is the primary energy obtained by subtracting the current power generation output from the power load.

[0082] The purchased electricity energy calculation unit 62 is connected to the purchased electricity primary energy conversion coefficient memory 72, and converts the electricity when the required electricity is purchased from the commercial power source 34 using the purchased electricity primary energy conversion coefficient to calculate the purchased electricity primary energy C, and sends it to the situation comparison unit 56.

[0083] Based on the result of the first comparison described above, the situation comparison unit 56 uses the follow-up primary energy A, the current primary energy B, and the purchased primary energy C to select whether it is better to follow up and control the amount of power generation in response to the required power load, or to maintain the current amount of power generation and purchase power from the commercial power source 34.

[0084] (Comparison of factors for selection) If it is determined in the first comparison that the current generated power Pg is greater than or equal to the required power load Pr, the current generated power is insufficient and the power must be increased.

[0085] In this case, as a second comparison, it is necessary to determine whether to respond to the increased power by load following or by power purchased from commercial power source 34, and a comparison is made between the following primary energy A and the sum of the current primary energy B and purchased primary energy C (A:B+C).

[0086] On the other hand, if it is determined in the first comparison that the required power load Pr<the current generated power Pg, the current generated power is in excess and therefore needs to be reduced.

[0087] In this case, since there is no need to purchase power from the commercial power source 34, a comparison is made between the follow-up primary energy A and the current primary energy B (A:B) as the third comparison.

[0088] The situation comparison unit 56 sends the result of the first comparison, the second comparison, or the third comparison to the power generation adjustment unit 74. Based on the comparison result, the power generation adjustment unit 74 determines whether to maintain the current power generation output or to change (follow) the power generation output to match the power load, and sends the determination result (control instruction) to the system operation control unit 76.

[0089] The system operation control unit 76 calculates the power generation output (maintaining or increasing power generation, etc.) based on the acquired control instructions, and sends a control instruction signal to the necessary controlled devices of the cogeneration system 10. As a result, the cogeneration system 10 is operated with a power generation output that generally follows the power consumption of the house 12, while taking primary energy into consideration and determining whether or not following is necessary.

[0090] The operation of this embodiment will be described below with reference to the flowchart of FIG.

[0091] In step 100, power information is acquired in accordance with the communication interval of the wireless communication unit 50 (when communication is successful), and the process proceeds to step .

[0092] In step 102, a first comparison is made, ie, a comparison between the required power load Pr and the current generated power Pg.

[0093] If it is determined in step 102 that the required power load Pr is equal to or greater than the current generated power Pg (Pr≧Pg), it is determined that the current generated power Pg is insufficient for the required power load P, and the process proceeds to step 104.

[0094] In step 104, it is determined whether to handle the increasing power by load following or by the power purchased from the commercial power supply 34. For this determination, a second comparison is executed.

[0095] That is, in step 104, a comparison between the follow-up primary energy A and the sum of the current primary energy B and the purchased power primary energy C is executed (A: B + C).

[0096] If an affirmative determination (A ≥ B + C) is made in this step 104, it is determined that if load following is performed, the primary energy will instead increase, and the process proceeds to step 106, where the current power generation output is maintained and the process returns to step 100. As a result, power is purchased (power purchase) from the commercial power supply 34.

[0097] Also, if a negative determination (A < B + C) is made in step 104, it is determined that if load following is performed, the primary energy will decrease more than in the case of power purchase, and the process proceeds to step 108, where the power generation output is changed (followed) to match the power load, and the process returns to step 100.

[0098] On the other hand, if it is determined in step 102 that the required power load Pr is less than the current power generation power Pg (Pr < Pg), it is determined that the current power generation power Pg is excessive with respect to the required power load P, and the process proceeds to step 110.

[0099] In step 110, it is determined whether to handle the decrease by load following or to reduce the power purchased from the commercial power supply 34. For this determination, a third comparison is executed.

[0100] That is, in step 110, a comparison between the follow-up primary energy A and the current primary energy B is executed (A: B).

[0101] Normally, it is common (positive slope) that the gas consumption decreases as the power generation amount decreases, as shown in *3 of FIG. 4(B).* In the *3 part, since it has a negative slope, when the power generation amount is decreased, the gas consumption will increase. Thus, depending on the current power generation output range, there may be cases where it does not have a positive slope, so the actual values are used for comparison.

[0102] In this step 110, if an affirmative determination (A≧B) is made, it is determined that the primary energy will increase instead when following the load, and the process proceeds to step 106, where the current power generation output is maintained and the process returns to step 100. As a result, the surplus power will be consumed inside the cogeneration device 10 (e.g., a heater).

[0103] Also, in step 110, if a negative determination (A<B) is made, it is determined that the primary energy will decrease when following the load, and the process proceeds to step 108, where the power generation output is changed (followed) to match the power load, and the process returns to step 100.

[0104] As described above, in this embodiment, throughout the entire range of the power generation output, the relationship with the gas consumption does not have stable characteristics (a directly proportional relationship with a positive slope) like near the rated value (e.g., 400W in FIGS. 4(A) and (B)). To avoid the situation where the primary energy increases instead when following the load, the necessity of load following is determined based on the actual values (followed primary energy A, current primary energy B, and purchased power primary energy C) for each communication interval. For this reason, power generation control that conforms to the power generation output - gas consumption characteristics can be realized not only near the rated value but also in all power generation regions.

[0105] (Modification Example 1 "Reverse Power Flow Suppression") When maintaining the current power generation output, the surplus is consumed inside the fuel cell (e.g., a heater). Even so, if a reverse power flow occurs, reverse power flow suppression is given top priority and the maintenance of the current power generation output this time is aborted.

[0106] The operation of the first modification will be described below with reference to the flowchart of Fig. 6. Note that the same steps as those in this embodiment (see Fig. 5) are given the same reference numerals, and the description thereof will be omitted.

[0107] As shown in FIG. 6, in step 110, a comparison is made between the follow-up primary energy A and the current primary energy B (A:B). If a positive determination is made (A≧B), it is determined that load following would actually increase the primary energy, and the process proceeds to step 112.

[0108] In step 112, it is determined whether or not the surplus power will be reversely flowed even if it is consumed inside the cogeneration system 10 (for example, by a heater).

[0109] In many cases, the propriety of reverse power flow is determined in advance, for example, by a contract, etc. Therefore, if the determination at step 112 is affirmative, reverse power flow will be performed while maintaining the current power generation, so even if A≧B, the process proceeds to step 108, where the power generation output is changed (tracked) to match the power load, and the process returns to step 100.

[0110] If the determination in step 112 is negative, the process proceeds to step 106, where the current power generation output is maintained, and the process returns to step 100. As a result, the surplus power is consumed inside the cogeneration system 10 (for example, in a heater).

[0111] (Variation 2: Variation of wireless system) The controller 14 of the cogeneration system 10 according to this embodiment is configured to acquire power information directly from the smart meter 36 installed in the house 12 via route B.

[0112] Here, a HEMS may be installed in the house 12. The HEMS manages and saves electricity and gas used in the house 12 in real time, and is also useful for combating global warming, such as reducing carbon dioxide emissions. By connecting home appliances to the HEMS and managing the electricity and gas usage on a monitor, visualization (monitor display) is realized and the home appliances are automatically controlled.

[0113] The HEMS obtains the data it manages from smart meters. In other words, the HEMS obtains the same power information as a smart meter.

[0114] Therefore, in a modified example, a communication protocol may be established between the controller 14 of the cogeneration device 10 and the HEMS using a communication means such as Wi-SUN HAN wireless communication, Wi-SUN Enhanced HAN wireless communication, specific low power wireless communication, or LPWA (Low Power Wide Area), and power information may be obtained from the HEMS.

[0115] (Variation 3: "Wired Variation") In this embodiment, the power information is acquired wirelessly, but it may be acquired via a wired system.

[0116] A cogeneration system 10A according to Modification 3 will be described with reference to Fig. 7. Note that the same components as those in the cogeneration system 10 of this embodiment (see Fig. 1) are given the same reference numerals, and description of their configurations will be omitted.

[0117] As shown in FIG. 7, in the cogeneration system 10A, a clamp-type current sensor 78 (hereinafter referred to as a CT clamp 50) is attached to the distribution board 40 (power line 38) inside the house 12.

[0118] The CT clamp 78 detects power information such as the current, power, and amount of power flowing through the power line 80. The detected power information is sent to the controller 14 of the cogeneration system 10 via the signal line 52.

[0119] In this case, since the CT clamp 78 is installed inside the house 12 and the cogeneration device 10 is installed outdoors, the signal line 80 necessarily needs to be passed through the wall of the house 12, and is wired through the penetration section 12A constructed by wall penetration work.

[0120] Even when power information is acquired by a wired method according to the above-described modified example, the power generation control of the present invention (power generation control based on the determination of the necessity of power generation by load following) can achieve the same effect. [Explanation of symbols]

[0121] 10 Cogeneration equipment 12 Houses 12A Penetration 14 Controller 15 Power line 16 Heat source machine 18 CPU 20 RAM 22 ROM 24 I / O 26 Bus 27 Hot water supply related control unit 28 Microcomputer 29 Power generation related control section 30 Mass storage 32 Remote Control 34 Commercial power supply 36 Smart Meters 38 Power line 40 Distribution board 42 Service breaker 46 Earth leakage breaker 48 Safety Breaker 48A safety breaker 50 Radio Communication Department 52 Power information acquisition section 54 Required power load calculation section 56 Situation comparison section (judgment section) 58 Current Power Generation Acquisition Department 60 Load following gas usage acquisition unit 62 Purchased electricity energy calculation unit 64 Power generation output-gas consumption table memory 66 Tracking primary energy calculation unit 68 Current gas usage acquisition unit 70 Current Primary Energy Calculation Unit 72 Purchased electricity primary energy conversion coefficient memory 74 Power generation adjustment unit (basic control unit) 76 System Operation Control Unit

Claims

1. A power generation control device that controls operation of a power generation device that is grid-connected to a commercial power source, a basic control unit that controls the amount of power generated by the power generation device in response to an increase or decrease in load so as to maintain the output of the commercial power source at a predetermined value; a determination unit that, when a load power requiring the amount of power generated by the power generation device is equal to or greater than a current power generation output, compares a difference between the load power and the current power generation output with a first usage amount, which is the usage amount of primary energy when the power generation amount is made to follow the difference based on control of the basic control unit, a second usage amount, which is the usage amount of primary energy at the current power generation output, and a third usage amount, which is the usage amount of primary energy when the difference is made to use power from the commercial power source, and maintains the current power generation output when the first usage amount is equal to or greater than the total value, and makes the power generation output follow the required power load based on control of the basic control unit when the first usage amount is less than the total value; A power generation control device having the same.

2. A power generation control device that controls the operation of a power generation device that is grid-connected to a commercial power source, a basic control unit that controls the amount of power generated by the power generation device in response to an increase or decrease in load so as to maintain the output of the commercial power source at a predetermined value; a determination unit that, when a load power requiring the amount of power generated by the power generation device is less than a current power generation output, compares a first usage amount, which is the amount of primary energy used when the amount of power generated is made to follow the difference between the load power and the current power generation output under the control of the basic control unit, with a second usage amount, which is the amount of primary energy used at the current power generation output, and maintains the current power generation output when the first usage amount is equal to or greater than the second usage amount, and makes the power generation output follow the required load power under the control of the basic control unit when the first usage amount is less than the second usage amount; A power generation control device having the same.

3. Computer, Operated as the power generation control device according to claim 1 or 2, Power generation control program.

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