JP2014200120A - Hybrid independent power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hybrid independent power generation system capable of performing stable power supply even when an electricity storage device having a smaller capacity is included, and capable of smoothing short-period output fluctuations in a solar power generation device, the hybrid independent power generation system comprising a combination of a solar power generation device, a thermal power generation device and an electricity storage device.SOLUTION: A hybrid independent power generation system includes a solar power generation device, an electricity storage device, a fuel-utilizing power generation device, and a power generation control device, and is connected to a load. In the hybrid independent power generation system, the power generation control device smooths short-period fluctuations in the amount of power generated by the solar power generation device using the electricity storage device, and supplies electrical power from the fuel-utilizing power generation device according to the electrical power demanded by the load.

Description

  The present invention relates to a solar power generation device, and more particularly to a combined self-sustaining power generation system using a combination of a thermal power generation device and a power storage device.

  In recent years, due to environmental problems and problems such as exhaustion of fossil fuels in the future, a power generation system using natural energy, such as solar power generation using solar energy, has attracted attention.

  However, solar power generation has a problem that the output fluctuates. The output decreases when it is cloudy or rainy. Also, it cannot generate electricity at night. Therefore, in order to perform stable power supply, it is necessary to smooth the output fluctuation.

  On the other hand, Patent Document 1 discloses a combined self-sustaining power generation system in which a natural energy power generation device such as solar power generation, a fuel-use power generation device such as thermal power generation, and a power storage device are combined. FIG. 11 illustrates the configuration of the composite self-supporting power generation system described in Patent Document 1, and will be described using this. In Patent Document 1, the combined self-sustained power generation system is called a self-sustained hybrid power generation system.

  A composite self-sustaining power generation system 101 illustrated in FIG. 11 includes a natural energy power generation device 102, a thermal power generation device 103, a power storage device 104, and a control device 105. The natural energy power generation apparatus 102 includes a solar power generation apparatus 106 and the like. The control device 105 operates the natural energy power generation device 102 as the main power generation device, and stores the surplus power in the power storage device 104 out of each power obtained by operating the thermal power generation device 103 as the auxiliary power generation device. Electric power is supplied to each load by the required amount while stabilizing the electric energy. When the power for the load is insufficient, the power stored in the power storage device 104 is used, and when the power stored in the power storage device 104 is also insufficient, the micro gas turbine power generation device 108 constituting the thermal power generation device 103 is changed. Using the electric power obtained by the auxiliary operation, power feeding is continued while eliminating the power shortage with respect to the load.

JP 2002-135879 A

  However, in the combined self-sustained power generation system described in Patent Document 1, since the power storage device 104 is used for the purpose of storing surplus power, there is a problem that a large-capacity power storage device is required.

  Moreover, there are various factors in the output fluctuation of solar power generation. For example, there is an output fluctuation that occurs when a cloud blocks the sunlight irradiated to the photovoltaic power generation apparatus. This occurs with a short period of a few seconds at the shortest. For example, when a solar power generation device is installed so as to face the sun at noon, the amount of power generation is greatest at noon, and the amount of power generation decreases in the morning and evening. In addition, no electricity can be generated at night. This output fluctuation is a cycle of several hours to one day. Furthermore, there is a difference in solar altitude between summer and winter, resulting in a difference in power generation. This output fluctuation is a one-year cycle. Thus, in photovoltaic power generation, there are output fluctuations of various periods depending on the factor.

  However, in the combined self-supporting power generation system described in Patent Document 1, there is a problem that smoothing of output fluctuations with a short cycle as described above in solar power generation is not considered.

  The invention of the present application solves the above-described problem, and in a combined self-sustained power generation system that combines a solar power generation device, a thermal power generation device, and a power storage device, stable power supply can be performed even with a smaller capacity power storage device. An object of the present invention is to provide a combined self-sustaining power generation system capable of smoothing output fluctuations in a short cycle of a solar power generation apparatus.

  In order to solve the above problems, according to one aspect of the present invention, a composite self-sustained power generation system of the present invention includes a solar power generation device, a power storage device, a fuel-use power generation device, and a power generation control device. A power generation control device connected to a load, wherein the power generation control device smoothes short cycle fluctuations in the amount of power generated by the photovoltaic power generation device using the power storage device, and the demand for the load Electric power is supplied from the fuel-use power generator according to the amount of electric power.

  According to another aspect of the present invention, the short period fluctuation of the power generation amount of the solar power generation apparatus in the previous period may be a period fluctuation that is difficult to follow in the fuel-use power generation apparatus.

  According to another aspect of the present invention, the power generation control device increases the power generation amount of the fuel-use power generation device when the power generation amount of the combined self-sustaining power generation system is less than the demand power amount of the load, When the power generation amount of the combined self-sustaining power generation system is larger than the demand power amount of the load, the power generation amount of the fuel-use power generation apparatus may be reduced.

  According to another aspect of the present invention, the power generation control device supplies power from the fuel-use power generation device when the power storage amount of the power storage device is equal to or lower than a first power storage amount reference value. When the power storage device is charged and the power storage amount of the power storage device becomes equal to or greater than a second power storage amount reference value that is greater than the first power storage amount reference value, the power storage device may be discharged.

  According to another aspect of the present invention, even if the power generation control device controls the power generation amount of the fuel-use power generation device to a minimum, the power generation amount of the combined self-sustained power generation system is the demand power of the load. When the amount is larger than the amount, the amount of power output from the solar power generation device to the load may be limited.

  According to another aspect of the present invention, the combined self-sustained power generation system is connected to an electric power system, and the power generation control device is configured such that the power generation amount of the combined self-supporting power generation system is greater than the demand power amount of the load. When there are many, surplus electric power may be made to flow backward to the electric power system.

  According to another aspect of the present invention, the power generation control device has a first frequency reference value lower than a standard frequency of an output of the combined self-sustained power generation system and a second frequency reference value higher than the standard frequency. And determining that the power generation amount of the composite self-sustained power generation system is less than the demand power amount of the load when the output frequency from the composite self-sustainable power generation system to the load is lower than the first frequency reference value. When the output frequency is higher than the second frequency reference value, it may be determined that the power generation amount of the combined self-sustaining power generation system is larger than the demand power amount of the load.

  According to another aspect of the present invention, a control method for a combined self-sustained power generation system according to the present invention controls a combined self-supported power generation system that supplies power generated by a solar power generation device and a fuel-use power generation device to a load. A method of smoothing short cycle fluctuations in the amount of power generated by the photovoltaic power generation device using a power storage device, and supplying power from the fuel-use power generation device according to the demand power amount of the load And a step of performing.

  According to another aspect of the present invention, the short period fluctuation of the power generation amount of the solar power generation apparatus in the previous period may be a period fluctuation that is difficult to follow in the fuel-use power generation apparatus.

  According to another aspect of the present invention, when the power generation amount of the combined self-sustained power generation system is less than the demand power amount of the load, the step of increasing the power generation amount of the fuel-use power generation apparatus; And a step of reducing the power generation amount of the fuel-use power generation apparatus when the power generation amount of the power generation system is larger than the demand power amount of the load.

  According to another aspect of the present invention, when the power storage amount of the power storage device is equal to or lower than a first power storage amount reference value, supplying power from the fuel-use power generation device and charging the power storage device And a step of discharging from the power storage device when the power storage amount of the power storage device becomes equal to or greater than a second power storage amount reference value greater than the first power storage amount reference value.

  According to another aspect of the present invention, even when the power generation amount of the fuel-use power generation apparatus is controlled to a minimum, when the power generation amount of the combined self-sustained power generation system is larger than the demand power amount of the load, You may have the step which restrict | limits the electric energy output to the said load from the said solar power generation device.

  According to another aspect of the present invention, when the power generation amount of the combined self-sustained power generation system is larger than the demand power amount of the load, the surplus power is reversely flowed to the power system connected to the composite self-supporting power generation system. You may have the step to make.

  According to another aspect of the present invention, when the output frequency from the combined self-sustained power generation system to the load is lower than a first frequency reference value lower than the standard frequency of the output of the combined self-supporting power generation system, Determining that the power generation amount of the composite self-sustained power generation system is less than the demand power amount of the load; and when the output frequency is higher than a second frequency reference value higher than the standard frequency, the composite self-sustained power generation Determining that the power generation amount of the system is greater than the demand power amount of the load.

  According to the above means, the composite self-sustained power generation system according to the present invention can perform stable power supply even with a smaller capacity power storage device, and smooth the output fluctuation in a short cycle of the solar power generation device. There is an effect that it can be performed.

It is a figure explaining the concept of control of the electric power generation amount of the composite type independent power generation system by this invention. It is a figure which shows the structure of the composite independent electric power generation system which concerns on a 1st Example. It is a figure which shows the control flow of the composite type self-supporting electric power generation system which concerns on a 1st Example. It is a figure which shows the state mode of the control of the electrical storage apparatus in 1st Example, and its transition. It is a figure which shows the structure of the composite independent electric power generation system which concerns on a 2nd Example. It is a figure which shows the control flow of the composite independent electric power generation system which concerns on a 2nd Example. It is a figure which shows the state mode of control of the electrical storage apparatus in a 2nd Example, and its transition. It is a figure explaining the example of the electrical storage amount control of the electrical storage apparatus in a 2nd Example. It is a figure which shows the structure of the composite independent electric power generation system which concerns on a 3rd Example. It is a figure which shows the control flow of the composite independent electric power generation system which concerns on a 3rd Example. It is a figure which shows the example of the conventional composite type self-supporting electric power generation system.

  First, the basic concept of the present invention will be described.

  As described above, in photovoltaic power generation, there are output fluctuations of various periods depending on the factor. On the other hand, there are various devices that can be used for smoothing output fluctuations of photovoltaic power generation, and they have various characteristics. For example, since a power storage device can generally charge and discharge electricity quickly, output fluctuations in a short cycle can be smoothed. However, since the power storage device itself does not generate electricity and the storage capacity is limited, for example, power supply at night when solar power generation is impossible is performed with the power stored in the power storage device in the daytime. If this is the case, a large-capacity power storage device is required. On the other hand, since the fuel-use power generator can generate power and can adjust the amount of power generation, it can smooth out fluctuations in output with a long cycle of solar power generation. However, the output adjustment of the fuel-use power generation apparatus can be performed only in units of minutes at the fastest, and such a quick output adjustment increases the failure rate, which is not desirable. Therefore, it is difficult to smooth the output fluctuation of the short cycle of photovoltaic power generation.

  In the present invention, the following control is performed in a combined self-sustained power generation system that combines a solar power generation device, a power storage device, and a fuel-use power generation device. First, the short-cycle output fluctuation of the solar power generation device is smoothed by the power storage device. Next, the power generation amount of the fuel-use power generation device is controlled so that the output power amount of the photovoltaic power generation device smoothed and smoothed by the power storage device and the demand power amount of the load are balanced.

  The concept of how the power generation amount of the solar power generation device and the fuel-use power generation device is controlled by the above control will be described with reference to FIG. Fig.1 (a) shows the conceptual diagram of the time change of the electric power generation amount of a solar power generation device. The horizontal axis is time, and represents the change in the amount of power generation per day. The vertical axis represents power. The same applies to other drawings in FIG. As shown to Fig.1 (a), the output electric energy of a solar power generation device has a fine fluctuation | variation by conditions, such as a weather. In addition, the amount of power generation is large during the daytime and cannot be generated at night.

  On the other hand, the conceptual diagram of the time change of the electric power generation amount after performing the smoothing process of the output electric energy of the solar power generation device by an electrical storage apparatus is shown in FIG.1 (b). The smoothing process eliminates the short period fluctuations in the amount of power generation shown in FIG. In other words, long-period fluctuations remain, such as a decrease in the amount of power generated by the solar power generation device when the cloudy weather continues and a change in the amount of power generated due to the altitude of the sun.

  Furthermore, the time change of the total power generation amount that combines the output power amount of the solar power generation device and the power generation amount of the fuel-use power generation device is shown in FIG. The curve of the upper thick line is the total power generation amount, and the power generation amount of the fuel-use power generator is controlled so that this is equal to the demand power amount of the load. The difference between the total power generation amount and the power generation amount of the solar power generation device after smoothing is the power generation amount by the fuel-use power generation device. In FIG. 1C, it is indicated by an upward arrow. That is, it is made to follow the fluctuation | variation of the long period of the electric power generation amount of a solar power generation device, and the fluctuation | variation of load by adjustment of the electric power generation amount of a fuel-use power generation device. As described above, since the change in the amount of power generation required for the fuel-use power generation device becomes slow, the power generation amount can be controlled without imposing an excessive burden on the fuel-use power generation device.

  As described above, in the present invention, control is performed so that the fluctuation factors to be smoothed are clearly divided and shared in accordance with the characteristics of the power storage device and the fuel-use power generation device. Thus, stable power supply can be performed even with a power storage device having a smaller capacity than that of a conventional combined self-sustained power generation system.

  Hereinafter, a method for specifically realizing the above concept will be described.

  The first embodiment of the present invention is a combined self-sustaining power generation system that combines solar power generation, thermal power generation, and a power storage device. This will be described below with reference to the drawings.

  FIG. 2 is a block diagram showing the configuration of the composite self-sustaining power generation system 1A according to the first embodiment. The combined self-sustaining power generation system 1A includes a solar power generation device 2, a power storage device 3, a thermal power generation device 4, and a power generation control device 5A. The power generation control device 5A supplies power to an external load. In FIG. 2, a solid line indicates a flow of direct current (DC), a double line indicates a flow of alternating current (AC), and a dotted line indicates a flow of information indicating the state of each part and control information for controlling each part.

  The solar power generation device 2 is a device that generates power using sunlight, and is connected to the DC / DC converter 6 in the power generation control device 5A.

  The power storage device 3 is configured by a device that stores electric power, such as a storage battery or a capacitor, and is connected to the charge controller unit 8A. A storage battery is a battery that can store and release electricity using a chemical reaction. There are lead storage batteries, nickel-cadmium storage batteries, lithium ion secondary batteries, and the like. A capacitor is a passive element that can store and discharge charges by electrostatic capacitance. Also called a capacitor. Examples of large storage capacities include electrolytic capacitors and electric double layer capacitors. The electric double layer capacitor has a larger capacity. In general, a capacitor has a smaller internal resistance than a storage battery, and can be charged and discharged at high speed. In general, a storage battery has a larger storage capacity per unit volume than a capacitor, but the difference is being reduced.

  The thermal power generation device 4 is a fuel-use power generation device that generates power using heat generated by burning fuel. Oil, coal, natural gas, waste, etc. can be used as the fuel. Moreover, the scale is various. The output is connected to the line to the load in the power generation control device 5A. The thermal power generation apparatus 4 has a power generation capacity sufficient to cover the maximum demand power of the load so that stable power supply can be performed even when there is no output of the solar power generation apparatus 2 such as in bad weather. In consideration of the time required for restarting the thermal power generation apparatus 4, the combined self-sustained power generation system 1A is not completely stopped during operation, and the minimum output capable of maintaining stable operation is Always generate electricity.

  The power generation control device 5 </ b> A is connected to the solar power generation device 2, the power storage device 3, and the thermal power generation device 4, controls them, and supplies the generated power to the load. At this time, the short cycle fluctuation of the output of the solar power generation device 2 is smoothed by using the power storage device 3, and the supply and demand balance between the power generation amount of the combined self-sustained power generation system 1A and the demand power amount of the load is maintained. To work. The power generation control device 5A further includes a DC / DC converter 6, a DC / AC converter 7, a charge controller 8A, and a controller 9A.

  The DC / DC conversion unit 6 is connected to the solar power generation device 2, the DC / AC conversion unit 7, and the charge controller unit 8A. In accordance with the power generation characteristics of the solar power generation device 2, the power generation point is controlled so as to obtain the maximum energy. This control is generally called MPPT (Maximum Power Point Tracking). Furthermore, it has the function to restrict | limit the output electric energy from the solar power generation device 2 to the DC / AC conversion part 7. FIG.

  The DC / AC converter 7 is a part that converts the direct current electricity obtained from the DC / DC converter 6 and the charge controller 8A into an alternating current. Also called an inverter. The output of the DC / AC converter 7 is connected to a load.

  The charge controller unit 8 </ b> A is a part that controls discharging from the power storage device 3 to the DC / AC conversion unit 7 or charging from the DC / DC conversion unit 6 to the power storage device 3. Further, the amount of power stored in the power storage device 3 is monitored.

  The DC / DC converter 6 and the DC / AC converter 7 may be collectively referred to as a PCS (Power Conditioning System) unit or a power conditioner unit.

  The control unit 9A is connected to the thermal power generation device 4, the DC / DC conversion unit 6, the DC / AC conversion unit 7, and the charge controller unit 8A, and obtains information representing the state of each device and each unit. Moreover, the information of the output electric energy of the DC / DC converter 6 and the frequency of the output from the power generation control device 5A to the load is obtained. Using these pieces of information, the operation of each device and each part is controlled.

  Next, control of the combined self-sustained power generation system 1A according to the first embodiment will be described.

  First, an overview. In the first embodiment of the present invention, short cycle fluctuations in the amount of output power of the photovoltaic power generator 2 are smoothed by the power storage device 3. Moreover, absorption of the slow fluctuation | variation of the output electric energy of the solar power generation device 2 and the tracking to the fluctuation | variation of the demand electric energy of load are performed by controlling the output of the thermal power generation apparatus 4. FIG. As described above, the thermal power generation apparatus 4 takes into account that it takes time to restart, and the combined self-sustained power generation system 1A is not completely stopped during operation, and is the minimum that can maintain stable operation. The output is always generated. The combined self-sustaining power generation system 1A takes out the maximum amount of power generation from the solar power generation device 2 and controls the thermal power generation device 4 to compensate for the shortage, but the demand power of the load is the minimum output of the thermal power generation device 4. When the output of the solar power generation device 2 is less than the sum, it is also necessary to limit the amount of output power from the solar power generation device 2 to the load.

  The details of the control flow of the hybrid self-sustained power generation system 1A will be described with reference to FIG.

  Immediately after the start of the system operation, first, the thermal power generation apparatus 4 is set to the minimum output and the power generation of the solar power generation apparatus 2 is started (S1: S represents a step, and so on). Specifically, the control unit 9A activates the thermal power generation apparatus 4 and issues an instruction to set the output to the minimum. In addition, DC / DC conversion and MPPT control are started to the DC / DC converter 6 and an instruction to supply power is issued.

  Next, it is determined whether there is a need to stop the system (S2). In the case of Yes, that is, in the case of stopping, system stop processing is performed (S3).

  In the case of No in S2, that is, when there is no need to stop the system, output smoothing of the solar power generation device 2 by the power storage device 3 and control of the amount of power stored in the power storage device 3 are performed (S4).

  The output smoothing of the solar power generation device 2 is performed as follows. 9 A of control parts monitor the output electric energy of the solar power generation device 2 which passed through the DC / DC conversion part 6, ie, the output electric energy of the DC / DC conversion part 6, and when the output electric energy increases suddenly, Then, the controller 8A controls the charge controller unit 8A so that the increased amount of electric power is accumulated in the power storage device 3. Conversely, when the output power amount of the DC / DC conversion unit 6 suddenly decreases, the charge controller unit 8 </ b> A is controlled so that the decrease in power is discharged from the power storage device 3 to the DC / AC conversion unit 7. By performing such control, the power input to the DC / AC conversion unit 7 has only a gradual variation with smooth fluctuations in the short period of the output power amount of the DC / DC conversion unit 6. Become. Therefore, in the subsequent processing, it is only necessary to adjust the power generation amount so as to absorb only moderate fluctuations.

  Further, the amount control of the power storage device 3 is performed as follows. 9 A of control parts monitor the electrical storage amount of the electrical storage apparatus 3, and control the charge controller part 8A and the DC / DC conversion part 6 so that the electrical storage amount may not become zero or a full charge state. If the amount of stored electricity is zero, power cannot be supplied from the power storage device 3 when the output power amount of the DC / DC converter 6 suddenly decreases, and if the amount of stored power is fully charged, This is because when the output power amount of the DC converter 6 suddenly increases, the increase cannot be accumulated in the power storage device 3. The amount of power stored in the power storage device is generally referred to as State Of Charge (SOC).

  Details of the control of the amount of power stored in the power storage device 3 in the process of S4 will be described later.

  After the process of S4 is performed, it is next determined whether the output frequency of the power generation control device 5A is less than F1 (S5). This is a process for determining whether the amount of supplied power is insufficient with respect to the amount of demand power of the load. Specifically, the control unit 9A measures the frequency F of the output part from the power generation control device 5A to the load and compares it with a reference value. In general, in an AC power system, the frequency decreases when the load demand power amount becomes larger than the supply power amount, and the frequency increases when the load demand power amount becomes smaller than the supply power amount. For this reason, it is possible to determine whether the amount of power supplied from the power generation system to the load is excessive or insufficient by monitoring frequency fluctuations. In the present embodiment, the reference value when the supply power amount is insufficient is the first frequency reference value F1, and the reference value when it is excessive is the second frequency reference value F2. The relationship between these frequency reference values and the AC standard frequency (60 Hz in Kansai and 50 Hz in Kanto) is F1 <standard frequency <F2. In the case of F <F1, it is determined that the output frequency decreases and the amount of power supplied is insufficient with respect to the amount of power demanded by the load. In the case of F1 ≦ F ≦ F2, it is determined that the output frequency is within the allowable range, that is, the supplied power amount is within the allowable range without excess or deficiency with respect to the demand power amount of the load. In the case of F> F2, it is determined that the output frequency increases and the amount of power supplied is excessive with respect to the amount of power demanded by the load.

  In the case of Yes in S5, that is, when the output frequency of the power generation control device 5A is less than F1, the supply power amount is insufficient with respect to the demand power amount of the load, and thus it is necessary to increase the supply power amount. Then, next, it is determined whether the output of the solar power generation device 2 is being restricted (S6).

  In the case of Yes in S6, that is, when the output of the solar power generation device 2 is being limited, the output limit amount of the solar power generation device 2 is decreased (S7). Specifically, the control unit 9 </ b> A controls the DC / DC conversion unit 6 so as to reduce the output limit amount of the solar power generation device 2. As a result, the amount of power supplied from the solar power generation device 2 to the load increases, and the system is controlled in a direction to solve the shortage of the power supply. When the process of S7 ends, the process returns to the determination process of S2.

  On the other hand, when it is No in S6, that is, when the output of the solar power generation device 2 is not being limited, the output of the thermal power generation device 4 is increased (S8). Specifically, the control unit 9A performs control to increase the output of the thermal power generation apparatus 4. The fact that the solar power generation device 2 is not in the output limit is because it is necessary to increase the output of the thermal power generation device 4 because the amount of power supplied from the solar power generation device 2 to the load cannot be increased any more. is there. As a result, the amount of power supplied from the thermal power generation apparatus 4 to the load increases, and the system is controlled in a direction to solve the shortage of the power supply. When the process of S8 ends, the process returns to the determination process of S2.

  As described above, the determination process of S6 and the processes of S7 and S8 are performed based on the output of the thermal power generation apparatus 4 in order to compensate for the shortage when the supply power amount is insufficient with respect to the demand power amount of the load. Is also controlled so that the output of the photovoltaic power generation device 2 is preferentially supplied to the load.

  If the answer is No in S5, that is, if the output frequency of the power generation control device 5A is F1 or higher, at least the supplied power amount is not insufficient with respect to the demand power amount of the load. Therefore, next, it is determined whether the output frequency of the power generation control device 5A exceeds F2 (S9). Specifically, the control unit 9A measures the frequency F of the output portion from the power generation control device 5A to the load, and compares this with F2. This is a process for determining whether the amount of supplied power is excessive relative to the amount of power demanded by the load.

  In the case of No in S9, when combined with the determination result in S5, F1 ≦ output frequency F ≦ F2 of the power generation control device 5A, and as described above, the output frequency is within the allowable range, that is, the amount of supplied power is a load. Therefore, it is within the allowable range without excess or deficiency with respect to the demand power amount. Accordingly, nothing is done as it is, and the process returns to the determination process of S2.

  If Yes in S9, that is, if the output frequency of the power generation control device 5A exceeds F2, the amount of power supplied is excessive with respect to the amount of power demanded by the load. In this case, it is necessary to reduce the amount of power supplied. Then, next, it is determined whether the output of the thermal power generator 4 is the minimum level (S10).

  If Yes in S10, that is, if the output of the thermal power generation device 4 is at a minimum level, the output of the thermal power generation device 4 cannot be reduced any more, so the output limit amount of the solar power generation device 2 is increased. (S11). Specifically, the control unit 9 </ b> A controls the DC / DC conversion unit 6 so as to increase the output limit amount of the solar power generation device 2. If output limitation has not been performed so far, output limitation is started. As a result, the amount of power supplied from the solar power generation device 2 to the load decreases, and the system is controlled in a direction to eliminate the excess of the amount of power supplied. When the process of S11 ends, the process returns to the determination process of S2.

  On the other hand, if the answer is No in S10, that is, if the output of the thermal power generation apparatus 4 is not the minimum level, the output of the thermal power generation apparatus 4 is decreased (S12). Specifically, the control unit 9A controls to reduce the output of the thermal power generation device 4. As a result, the amount of power supplied from the thermal power generation apparatus 4 to the load decreases, and the system is controlled in a direction to eliminate the excess of the amount of power supplied. When the process of S12 ends, the process returns to the determination process of S2.

  In this way, the determination process of S10 and the processes of S11 and S12, when the supplied power amount is excessive with respect to the demand power amount of the load, in order to reduce the excess amount, Control is performed so that priority is given to limiting, in other words, the output of the photovoltaic power generation device 2 is supplied to the load with priority as much as possible.

  Detailed contents of the control of the amount of power stored in the power storage device 3 in the process of S4 will be described with reference to FIG.

  FIG. 4 is a diagram illustrating the three modes used for controlling the amount of power stored in the power storage device 3 according to the present embodiment and the transition thereof.

  The normal mode is a state in which the amount of power stored in the power storage device 3 is not excessively large or small, and the fluctuation can be smoothed with any increase or decrease in the short period of the output power amount of the solar power generation device 2. It is a mode indicating that.

  The discharge prohibition mode is a mode in which only the charge is possible in order to prevent overdischarge because the storage amount of the power storage device 3 is insufficient. When in the discharge inhibition mode, smoothing is possible when the output power amount of the solar power generation device 2 suddenly increases, but smoothing is not possible when the output power amount of the solar power generation device 2 suddenly decreases. .

  The charge prohibition mode is a mode in which only a discharge is possible in order to prevent overcharge because the amount of power stored in the power storage device 3 is excessive. Smoothing can be performed when the output power amount of the solar power generation device 2 suddenly decreases, but smoothing cannot be performed when the output power amount of the solar power generation device 2 suddenly increases.

  The arrows (1) to (4) in FIG. 4 indicate transitions between modes. Transition is performed by comparing the amount of power stored in the power storage device 3 with a predetermined reference value. Four reference values are used: SOCmax, SOCmin, a, and b. SOCmax is the maximum power storage amount allowed in the power storage device 3, and SOCmin is the minimum power storage amount allowed in the power storage device 3. The setting differs depending on the type of power storage device. For example, when a storage battery is used as the power storage device, there is a problem that the storage battery is vulnerable to overcharge and overdischarge. For this reason, SOCmax is set with a little allowance from the upper limit value of the storage amount of the power storage device, and SOCmin is set with a slight allowance from 0 as the lower limit value of the storage amount of the power storage device, that is, 0. The relationship between these values including a and b is determined to satisfy SOCmax> b> a> SOCmin. When a capacitor is used as the power storage device, the capacitor has no problem of overdischarge or overcharge. Therefore, even if SOCmax is set to the upper limit value of the power storage amount of the power storage device and SOCmin is set to 0, which is the lower limit value of the power storage amount of the power storage device. good.

  (1) of FIG. 4 shows the transition from the normal mode to the discharge inhibition mode. This transition occurs when the amount of power stored in the power storage device 3 becomes SOCmin or less. In contrast, (2) of FIG. 4 shows a transition from the discharge inhibition mode to the normal mode. This transition occurs when the amount of power stored in the power storage device 3 is greater than or equal to a. As described above, the reference value used to determine the transition between the normal mode and the discharge inhibition mode differs depending on the transition direction, and a> SOCmin as described above. This is because hysteresis is provided to prevent frequent mode transitions when the amount of electricity stored in the electricity storage device 3 fluctuates near the reference value.

  (3) in FIG. 4 shows a transition from the normal mode to the charge inhibition mode. This transition occurs when the amount of power stored in power storage device 3 is equal to or higher than SOCmax. On the other hand, (4) in FIG. 4 shows a transition from the charge inhibition mode to the normal mode. This transition occurs when the amount of power stored in the power storage device 3 is equal to or less than b. As described above, the reference value used for determining the transition between the normal mode and the charge inhibition mode differs depending on the transition direction, and SOCmax> b as described above. This is because, similarly to the above, hysteresis is provided in order to prevent frequent mode transitions when the amount of electricity stored in the electricity storage device 3 fluctuates near the reference value.

  In this way, three control modes are defined, the mode is changed according to the state of the power storage amount of the power storage device 3, and an appropriate smoothing process is performed in each mode.

  As described above, in the present embodiment, short cycle fluctuations in the output power amount of the solar power generation device 2 are smoothed by the power storage device 3. Thereby, it has the effect that the output fluctuation of the short period by the weather peculiar to a solar power generation device can be suppressed effectively. Moreover, absorption of the slow fluctuation | variation of the output electric energy of the solar power generation device 2 and the tracking to the fluctuation | variation of the demand electric energy of load are performed by controlling the output of the thermal power generation apparatus 4. FIG. As a result, the power storage device 3 only needs to smooth out fluctuations in the short period of the output power amount of the solar power generation device 2, and its power storage capacity is small compared to the case where power storage of surplus power is intended. It has the effect that it can be done. This also has the effect of being able to construct a composite independent power generation system at a lower cost. In addition, even a power generation system based on natural energy, such as sunlight, which fluctuates due to weather or the like, has an effect that a stable output can be obtained. Furthermore, the thermal power generation device 4 only needs to absorb the fluctuation of the slow output power amount of the solar power generation device 2 and follow the fluctuation of the demand power amount of the load, and adjust the output of the thermal power generation device 4 in a short cycle. Since it does not need to be calculated | required, it has the effect that the burden to an apparatus is small and leads to reliability improvement.

  In the present embodiment, the output power of the solar power generation device 2 is controlled to be supplied to the load with priority over the output power of the thermal power generation device 4. Moreover, the solar power generation device 2 always performs MPPT control except when the output of the solar power generation device 2 is limited because the supplied power amount is too large compared to the demand power amount. As a result, even if the output power amount of the solar power generation device 2 changes every moment due to the weather or the like, the output power can be supplied to the load without being wasted as much as possible. In other words, it is possible to minimize the amount of power supplied by the thermal power generation apparatus 4 used in combination, and to minimize the fuel necessary for the operation of the thermal power generation apparatus 4.

  Further, in this embodiment, the thermal power generation device 4 has a power generation capacity sufficient to cover the maximum demand power of the load so that stable power supply can be performed even when there is no output of the solar power generation device 2 such as in bad weather. I have it. From this, it is possible to easily convert to an existing thermal power generation apparatus by adding a solar power generation apparatus and the above-described controller to a combined self-sustaining power generation system as in this embodiment. It has the effect. Furthermore, since the added solar power generation device can be used even with a small capacity, there is an effect that it is possible to start using the solar power generation device after the installation is completed.

  Further, the control flow of the combined self-sustained power generation system 1A in the present embodiment does not depend on the size of the thermal power generation system 4. Therefore, it has an effect that it can be widely applied from a small scale to a large scale.

  Furthermore, in the present embodiment, the output of the solar power generation device 2 is smoothed in advance by the power storage device 3, so that it is possible to balance the power supply and demand by simply measuring the frequency of the output portion from the power generation control device 5A to the load. It is possible to determine and adjust the output of the thermal power generator 4. As described above, there is an effect that it is easy to adjust the supply and demand balance of electric power while being a combined self-sustaining power generation system combining a solar power generation device and a thermal power generation device.

  As in the first embodiment, the second embodiment of the present invention is a combined self-sustained power generation system that combines solar power generation, thermal power generation, and a power storage device. This will be described below with reference to the drawings.

  FIG. 5 is a block diagram showing a configuration of a combined self-sustaining power generation system 1B according to the second embodiment. The difference from the first embodiment is that an AC / DC converter 10 is added. Therefore, in the following, description of the same part is omitted, and only different parts are described.

  The power generation control device 5B is connected to the solar power generation device 2, the power storage device 3, and the thermal power generation device 4, and controls them and supplies the generated power to the load. At this time, the short cycle fluctuation of the output of the solar power generation device 2 is smoothed by using the power storage device 3, and the supply and demand balance between the total power generation amount of the combined self-sustaining power generation system 1B and the demand power amount of the load is maintained. To work. The power generation control device 5B includes a DC / DC conversion unit 6, a DC / AC conversion unit 7, a charge controller unit 8B, a control unit 9B, and an AC / DC conversion unit 10.

  The charge controller unit 8B is different from the charge controller unit 8A of the first embodiment in that it has an input of power from the AC / DC conversion unit 10. The charge controller unit 8B is a part that controls discharging from the power storage device 3 to the DC / AC conversion unit 7 or charging from the DC / DC conversion unit 6 and the AC / DC conversion unit 10 to the power storage device 3. Further, the amount of power stored in the power storage device 3 is monitored.

  The control unit 9B is connected to the thermal power generation device 4, the DC / DC conversion unit 6, the DC / AC conversion unit 7, the charge controller unit 8B, and the AC / DC conversion unit 10, and obtains information indicating the status of each device and each unit. ing. Moreover, the information of the output electric energy of the DC / DC converter 6 and the frequency of the output from the power generation control device 5B to the load is obtained. Using these pieces of information, the operation of each device and each part is controlled.

  The AC / DC conversion unit 10 converts the output power of the thermal power generation apparatus 4 that is alternating current into direct current, and supplies the direct current to the charge controller unit 8B.

  As described above, the second embodiment is different from the first embodiment. Due to these differences, the biggest difference between the first embodiment and the second embodiment is that the power required for charging the power storage device 3 is only the power from the solar power generation device 2 in the first embodiment. In contrast, the second embodiment is configured such that the electric power from the thermal power generator 4 can also be used. In said 1st Example, in the smoothing of the output of the photovoltaic power generation apparatus 2 by the electrical storage apparatus 3, when the electrical storage apparatus 3 is in discharge prohibition mode, the output of the photovoltaic power generation apparatus 2 decreases suddenly. Smoothing is not possible. Further, when the power storage device 3 is in the charge prohibition mode, smoothing is not possible when the output of the solar power generation device 2 suddenly increases. As described above, in the first embodiment, there is a case where the output smoothing of the solar power generation device 2 by the power storage device 3 cannot be performed. The second embodiment further solves this problem.

  Next, control of the combined self-sustaining power generation system 1B according to the second embodiment will be described.

  The control flow of the combined self-sustained power generation system 1B will be described in detail with reference to FIG. Compared with the control flow of the composite independent power generation system 1A shown in FIG. 2, S4 is changed to S104, S5 is changed to S105, and S9 is changed to S109. Since the other processes are the same, the description is omitted and only the changed and added processes are described.

  Regarding S105 and S109, only the change due to the change of the power generation control device 5A in the first embodiment to the power generation control device 5B in the second embodiment is the same as the processing itself in S5 and S9.

  As described above, S4 is changed to S104 because the power for charging the power storage device 3 is changed to use the power from the thermal power generation device 4 in addition to the power from the solar power generation device 2. This is because. Detailed contents of the control of the amount of power stored in the power storage device 3 in the process of S104 will be described with reference to FIG.

  FIG. 7 is a diagram illustrating three modes used for controlling the amount of power stored in the power storage device 3 according to the present embodiment and transitions thereof. This is slightly different from the processing mode in the first embodiment described with reference to FIG.

  The normal mode is a state in which the amount of power stored in the power storage device 3 is not excessively large or small, and the fluctuation can be smoothed with any increase or decrease in the short period of the output power amount of the solar power generation device 2. It is a mode indicating that. This is the same as the normal mode in the first embodiment.

  The charging mode is a mode that represents a state where the amount of power stored in the power storage device 3 is insufficient. The output of the solar power generation device 2 is smoothed in the same manner as in the normal mode, but in addition to that, the power supplied from the thermal power generation device 4 by the AC / DC conversion unit 10 is used for the shortage of the storage amount. The charging process is performed at the same time. When such processing is performed, the amount of power supplied to the load from the combined self-sustainable power generation system 1B decreases, but this is adjusted by processing for balancing the demand power amount of the load and the power supply amount after S105. . The charge mode corresponds to the discharge inhibition mode in the first embodiment. In the discharge prohibition mode, the amount of power stored in the power storage device 3 is insufficient and no further discharge is possible, so discharging is prohibited. However, in the charge mode, the shortage of the power storage amount in the power storage device 3 is detected from the thermal power generation device 4. By charging with electric power, further discharge is possible.

  The discharge mode is a mode that represents a state where the power storage amount of the power storage device 3 is excessive. The smoothing of the output of the solar power generation device 2 is performed in the same manner as in the normal mode. In addition, the charge controller 8B is controlled in response to the excessive storage amount, and the excess is DC / AC converted. The part 7 is discharged. That is, more power is output than when only smoothing is performed. At this time, if the discharge amount is suddenly increased, the balance between the demand power amount of the load and the supply power amount is greatly lost, so the discharge amount is slowly increased. When such a process is performed, the amount of power supplied to the load from the combined self-sustainable power generation system 1B increases, but this is adjusted by a process of balancing the demand power amount of the load and the power supply amount after S105. . The discharge mode corresponds to the charge inhibition mode in the first embodiment. In the charge prohibition mode, charging is prohibited because the amount of power stored in the power storage device 3 is excessive and cannot be further charged. However, in the charge mode, the excessive amount of power stored in the power storage device 3 is converted into a DC / AC converter. By discharging to 7, it is possible to charge further.

  The arrows of (5) to (8) in FIG. 7 indicate transitions between modes. Transition is performed by comparing the amount of power stored in the power storage device 3 with a predetermined reference value. In addition to SOCmax and SOCmin as in the first embodiment, a total of six reference values c1, c2, d1, and d2 are used. The relationship between these reference values is determined so that SOCmax> d1> d2> c2> c1> SOCmin.

  (5) in FIG. 7 shows a transition from the normal mode to the charging mode. This transition occurs when the amount of power stored in the power storage device 3 is equal to or less than c1. (6) in FIG. 7 shows the transition from the charging mode to the normal mode. This transition occurs when the amount of power stored in the power storage device 3 is equal to or greater than c2. As described above, the reference value used for determining the transition between the normal mode and the charging mode differs depending on the transition direction, and c2> c1 as described above. This is because hysteresis is provided to prevent frequent mode transitions when the amount of electricity stored in the electricity storage device 3 fluctuates near the reference value.

  (7) in FIG. 7 shows a transition from the normal mode to the discharge mode. This transition occurs when the amount of power stored in the power storage device 3 becomes d1 or more. On the other hand, (8) in FIG. 7 shows a transition from the discharge mode to the normal mode. This transition occurs when the amount of power stored in the power storage device 3 becomes d2 or less. As described above, the reference value used for determining the transition between the normal mode and the discharge mode differs depending on the transition direction, and d1> d2 as described above. This is because, similarly to the above, hysteresis is provided in order to prevent frequent mode transitions when the amount of electricity stored in the electricity storage device 3 fluctuates near the reference value.

  In this way, three control modes are defined, the mode is changed according to the state of the power storage amount of the power storage device 3, and an appropriate smoothing process is performed in each mode.

  An example of a change in the amount of power stored in the power storage device 3 by the above control will be described with reference to FIG. The horizontal axis represents time, and the vertical axis represents the amount of power stored in the power storage device 3. In the figure, p1 to p6 indicate characteristic time points in the change in the amount of power stored in the power storage device 3, and the phenomenon and operation at each time point will be described in order.

  First, at p1, the control of the power storage device 3 is performed in the normal mode, and it is assumed that the output of the solar power generation device 2 suddenly decreases. For example, it is a case where clouds block sunlight from the solar power generation device 2. Due to this smoothing of the output drop, the amount of electricity stored in the electricity storage device 3 decreases rapidly.

  At the time of p2, the amount of power storage becomes c1 or less, and the control of the power storage device 3 shifts to the charging mode. In the charging mode, charging is performed using the electric power supplied from the thermal power generation device 4 by the AC / DC conversion unit 10, so that the amount of stored electricity is recovered from p2 to p3. The amount of stored electricity does not recover immediately after p2, because the thermal power generation device 4 cannot increase or decrease its output suddenly as described above, and the output actually increases after performing control to increase the output. This is because there is a time lag before doing. Even during this time lag, the amount of power storage may further decrease and become c1 or less for smoothing. Therefore, c1 is set higher than SOCmin so as to provide a margin for the amount of power storage.

  At p3, since the amount of power stored in the power storage device 3 has recovered until it reaches c2, the control of the power storage device 3 shifts to the normal mode. Thus, c2 is set to a value larger than c1, and since hysteresis is provided in the transition between the normal mode and the charging mode, the mode is frequently changed, and the thermal power generator 4 is frequently adjusted. This is done so that it does not happen. This is because if the thermal power generation device 4 is frequently adjusted, its efficiency deteriorates.

  Next, it is assumed that the output of the solar power generation device 2 suddenly increases at the time of p4. For example, this is a case where clouds that have blocked the sunlight to the solar power generation device 2 have passed and the sunlight has recovered. In order to smooth this increase, the amount of power stored in the power storage device 3 increases rapidly.

  At the time of p5, the charged amount becomes d1 or more, and the control of the power storage device 3 shifts to the discharge mode. In the discharge mode, the charge controller 8 </ b> B is controlled to discharge the excessive charged amount to the DC / AC converter 7. At this time, if the discharge amount is suddenly increased, the balance between the demand power amount of the load and the supply power amount is greatly lost, so the discharge amount is slowly increased. In this way, the amount of electricity stored in the electricity storage device 3 cannot be reduced suddenly, and during that time, the amount of electricity stored may further increase due to smoothing and become d1 or more. D1 is set to be lower than SOCmax so that a margin is provided.

  At p6, since the amount of power stored in the power storage device 3 has recovered until d2 or less, the control of the power storage device 3 shifts to the normal mode. In this way, d2 is set to a value smaller than d1, and hysteresis is provided in the transition between the normal mode and the discharge mode, so that the mode does not frequently change. If the mode change frequently occurs, the amount of stored electricity from the charge controller 8B is frequently turned on / off. As a result, the output power amount of the smoothed photovoltaic power generation apparatus 2 frequently fluctuates, and it is necessary to frequently adjust the thermal power generation apparatus 4 to absorb the fluctuation, and the efficiency of the thermal power generation apparatus 4 deteriorates. It is to do.

  In the first embodiment, SOCmin is used as the reference value for the transition from the normal mode to the discharge inhibition mode, and SOCmax is used as the reference value for the transition from the normal mode to the charge inhibition mode. In contrast, in this embodiment, c1 is used as a reference value for transition from the normal mode to the charging mode, and c1> SOCmin. Further, d1 is used as a reference value for the transition from the normal mode to the discharge mode, and the relationship is SOCmax> d1. The reason for this difference is as follows.

  In the discharge prohibition mode in the first embodiment, since discharge is prohibited, the amount of power stored in the power storage device 3 never falls below the reference value for mode transition. Therefore, there is no particular problem even if SOCmin is used as a reference value for transition from the normal mode to the discharge inhibition mode. On the other hand, as described above, in the present embodiment, the charged amount may further decrease in the charging mode and become c1 or less, so c1 is set higher than SOCmin so that the charged amount can be provided. It is.

  Similarly, since charging is prohibited in the charge prohibition mode in the first embodiment, the amount of power stored in the power storage device 3 does not exceed the reference value for mode transition. Therefore, there is no particular problem even if SOCmax is used as a reference value for transition from the normal mode to the charge inhibition mode. On the other hand, in the present embodiment, as described above, in the discharge mode, there is a possibility that the charged amount further increases and becomes d1 or more. Therefore, d1 is set lower than SOCmax so as to allow a margin for the charged amount. It is.

  Thus, in the first embodiment, the power storage device 3 is used in the range from SOCmax to SOCmin, whereas in this embodiment, the power storage device 3 is used in the range from d1 to c1, and the range from SOCmax to SOCmin. Narrower. At first glance, it seems that this embodiment is less efficient in using the storage capacity of the power storage device 3, in other words, requires a larger capacity power storage device 3. However, actually, the storage capacity of the power storage device 3 may be smaller in this embodiment. The reason is as follows.

  In the first embodiment, as described above, positive control is not performed so as to restore the bias of the amount of power stored in the power storage device 3, and smoothing cannot be performed in some cases. In order to prevent the state where smoothing cannot be performed as much as possible, it is necessary to increase the storage capacity of the power storage device 3. On the other hand, in this embodiment, when the amount of electricity stored in the electricity storage device 3 is less than or equal to c1, or more than d1, the amount of electricity stored is actively controlled to return it to the normal state. Therefore, smoothing can always be performed. For this reason, smoothing equivalent to or higher than that of the first embodiment can be performed with a smaller storage capacity.

  As described above, in this embodiment, when the power storage amount of the power storage device 3 is insufficient, the power storage device 3 is charged using the power generated by the thermal power generation device 4. As a result, when the amount of power supplied to the load becomes insufficient, the power generation amount of the thermal power generation apparatus 4 is increased. Further, when the amount of power stored in the power storage device 3 becomes excessive, excessive power is discharged. As a result, when the amount of power supplied to the load becomes excessive, the power generation amount of the thermal power generation apparatus 4 is decreased.

  The present embodiment has the same effect as the first embodiment, and also has the following new effects by the above processing.

  By the processing of the present embodiment, the amount of power stored in the power storage device 3 can always be kept appropriate, and overdischarge and full charge can be prevented. Moreover, it has the effect that the output fluctuation | variation of the short period of the solar power generation device 2 can always be smoothed. In the first embodiment, as described above, depending on the state of the amount of power stored in the power storage device 3, the solar power generation device 2 may not be smoothed.

  In the first embodiment, as described above, when the control of the power storage device 3 is in the discharge prohibition mode, smoothing when the output of the solar power generation device 2 suddenly decreases cannot be performed. When the control is in the charge prohibition mode, smoothing was not possible when the output of the solar power generation device 2 suddenly increased. Among these, the former is difficult to deal with, but the latter can be dealt with by limiting the output of the solar power generation device 2 in the DC / DC converter 6. However, a part of the output of the solar power generation device 2 is discarded. On the other hand, in the present embodiment, smoothing is not impossible, and therefore, the possibility that the output of the solar power generation device 2 is limited is lowered, and MPPT control can be performed for a longer time. For this reason, it has the effect that the electric power generated by the solar power generation device 2 can be used more efficiently. In addition, since this reduces the operation of the thermal power generation apparatus 4, the fuel consumption of the thermal power generation apparatus 4 is further reduced.

  Further, as described above, according to the present embodiment, the storage capacity of the power storage device 3 can be equalized or smoothed with a smaller storage capacity than that of the first embodiment. Therefore, the power storage capacity of the power storage device 3 can be further reduced.

  As in the second embodiment, the third embodiment of the present invention is a combined self-sustained power generation system that combines solar power generation, thermal power generation, and a power storage device, but compared to the second embodiment, The difference is that it is connected to the power system and allows reverse power flow. The surplus power generated by the solar power generation device is allowed to flow backward to the power system, so that the power generation amount of the solar power generation device can be used effectively. In this embodiment, reverse power flow to the power system is performed, but no power is received from the power system.

  The present embodiment will be described below with reference to the drawings.

  FIG. 9 is a block diagram showing a configuration of a combined self-sustaining power generation system 1C according to the third embodiment. The difference from the second embodiment is that a reverse power flow control device 11 is added. Therefore, in the following, description of the same part is omitted, and only different parts are described.

  The power generation control device 5 </ b> C is connected to the solar power generation device 2, the power storage device 3, the thermal power generation device 4, and the reverse power flow control device 11, controls them, and outputs the generated power to the reverse power flow control device 11. At this time, the short cycle fluctuation of the output of the solar power generation device 2 is smoothed by using the power storage device 3, and the supply and demand balance between the total power generation amount of the combined self-sustaining power generation system 1C and the demand power amount of the load is maintained. To work. Furthermore, the power generation control device 5C includes a DC / DC conversion unit 6, a DC / AC conversion unit 7, a charge controller unit 8B, a control unit 9C, and an AC / DC conversion unit 10.

  The control unit 9C is connected to the thermal power generation device 4, the DC / DC conversion unit 6, the DC / AC conversion unit 7, the charge controller unit 8B, the AC / DC conversion unit 10, and the reverse power flow control device 11, and each device and each unit Information indicating the state is obtained. In addition, information on the output power amount of the DC / DC converter 6 and the frequency of the output from the power generation control device 5C to the reverse power flow control device 11 is obtained. Using these pieces of information, the operation of each device and each part is controlled.

  The reverse power flow control device 11 receives the power from the power generation control device 5C and outputs it to the load and the power system. At this time, when the output power amount from the power generation control device 5C is larger than the demand power amount of the load, the surplus power is caused to flow backward to the power system. The basic operation of reverse power flow is to make a reverse power flow when there is surplus power. In this embodiment, it is assumed that such a basic operation is performed. Moreover, the reverse power flow control device 11 restricts not to receive power from the power system. Further, the reverse power flow control device 11 detects whether or not a reverse power flow is generated toward the power system.

  As mentioned above, the third embodiment is different from the second embodiment. Due to these differences, the biggest difference between the second embodiment and the third embodiment is that, as described above, when surplus of power generated by the combined self-sustaining power generation system 1C occurs, the second embodiment In the third embodiment, the output of the photovoltaic power generator 2 is limited, that is, the surplus power is discarded. In the third embodiment, the surplus power can be reversely flowed to the power system. Is a point. This is particularly effective when the solar power generation device 2 is large and surplus power is likely to be generated. In the present embodiment, as described above, reverse power flow to the power system is performed, but power reception from the power system is not performed. The amount of power supplied to the load is all covered by the power generation of the combined self-sustaining power generation system 1C.

  Next, control of the hybrid self-sustaining power generation system 1C according to the third embodiment will be described.

  The details of the control flow of the combined self-sustained power generation system 1C will be described with reference to FIG. Compared with the control flow of the combined self-sustained power generation system 1B shown in FIG. 7, the processing after S104 is greatly changed. Therefore, only this part will be described.

  Regarding S205, the power generation control device 5B in the second embodiment is only changed due to the change to the power generation control device 5C in the third embodiment, and the process itself is the same as S105. However, for the sake of easy understanding, the processing from S205 will be described.

  In S205, it is determined whether the output frequency from the power generation control device 5C to the reverse power flow control device 11 is less than F1. This is a process for determining whether the amount of supplied power is insufficient with respect to the amount of demand power of the load. Specifically, the control unit 9C measures the frequency F of the output portion from the power generation control device 5C to the reverse power flow control device 11, and compares this with F1.

  In the case of Yes in S205, that is, when the output frequency from the power generation control device 5C to the reverse power flow control device 11 is less than F1, the supplied power amount is insufficient with respect to the demand power amount of the load. It is necessary to increase the amount of power supply. For this reason, the output of the thermal power generator 4 is increased (S8). Specifically, the control unit 9 </ b> C performs control to increase the output of the thermal power generation apparatus 4. As a result, the amount of power supplied from the thermal power generation apparatus 4 is increased, and the system is controlled in a direction to eliminate the shortage of power supply. When the process of S8 ends, the process returns to the determination process of S2.

  In the second embodiment, after the process of S105 corresponding to S205, it is determined whether the output of the solar power generation device 2 is being restricted (S6). However, in the present embodiment, since the reverse power flow is performed when surplus power is generated, the output of the solar power generation device 2 is not limited, so the determination process of S6 is not necessary.

  If No in S205, that is, if the output frequency from the power generation control device 5C to the reverse power flow control device 11 is F1 or more, at least the supplied power amount is not insufficient with respect to the demand power amount of the load. become. Therefore, it is next determined whether the composite self-sustained power generation system 1C is performing reverse power flow to the power system (S13). Specifically, the control unit 9 </ b> C acquires information about whether or not a reverse power flow is occurring from the reverse power flow control device 11.

  In the case of No in S13, it means that reverse power flow is not performed. In the present embodiment, as described above, when there is surplus power, the power flows backward without permission. From this, the fact that reverse power flow is not performed means that surplus power is not generated. When combined with the determination result of S205, the supplied power amount is neither insufficient nor excessive with respect to the load demand power amount. Accordingly, nothing is done as it is, and the process returns to the determination process of S2.

  If Yes in S13, that is, if reverse power flow to the power system is being performed, surplus power is generated. The present embodiment is not intended to actively reverse flow, but is intended to reduce the amount of power generated by the thermal power generator 4 as much as possible to suppress fuel consumption. For this reason, if surplus power is generated, it is necessary to first attempt to reduce the amount of power generated by the thermal power generation apparatus 4. Then, next, it is determined whether the output of the thermal power generator 4 is the minimum level (S10).

  If Yes in S10, that is, if the output of the thermal power generation device 4 is at the minimum level, the output of the thermal power generation device 4 cannot be reduced any further, so nothing is done, and the determination process of S2 is resumed. Return.

  On the other hand, if the answer is No in S10, that is, if the output of the thermal power generation apparatus 4 is not the minimum level, the output of the thermal power generation apparatus 4 is decreased (S12). Specifically, the control unit 9C performs control so as to decrease the output of the thermal power generation apparatus 4. As a result, the amount of power supplied from the thermal power generation apparatus 4 is reduced, and the system is controlled to reduce the reverse power flow to the power system. When the process of S12 ends, the process returns to the determination process of S2.

  Thus, the determination process of S10 and the process of S12 are thermal power as a method for reducing the reverse power flow when the supplied power amount is excessive with respect to the demand power amount of the load and the reverse power flow is generated. The priority is given to limiting the output of the power generation device 4, in other words, the output of the solar power generation device 2 is controlled as much as possible to be supplied to the load and the power system.

  By having the above-described configuration and processing, this embodiment has the same effects as the first and second embodiments, and also has the following effects.

  In the present embodiment, in the combined self-sustaining power generation system 1C, the power generation amount of the thermal power generation apparatus 4 is controlled to be a necessary minimum so as not to generate surplus power as much as possible, and when surplus power is generated The power is reversely flowed to the power system. Thereby, the electric power generated by the solar power generation device 2 is always efficiently extracted by the MPPT control, and is supplied to the load or the electric power system without being wasted at all.

  In the present embodiment, surplus power is not stored in the power storage device 3 but is reversely flowed to the power system. Therefore, even when the facilities of the solar power generation device 2 are increased, the power storage capacity of the power storage device 3 is extremely reduced. The increase in the storage capacity of the power storage device 3 does not need to be increased, and it has the effect that the increase in the output smoothing capability required by the increase in the power generation capacity of the solar power generation device 2 can be covered.

  In addition, in order to preferentially adjust the amount of power generation in the combined self-sustaining power generation system 1C, the reverse power flow to the power system does not frequently occur, and the output of the solar power generation device 2 is smoothed by the power storage device 3. As a result, the power with relatively moderate fluctuations flows backward. Therefore, it has an effect that the influence on the power system is small.

  In said 1st-3rd Example, it has described regarding control of the composite type independent electric power generation system which combined the solar power generation device, the electrical storage apparatus, and the fuel-use type power generation device. This is not only for solar power generators, but also for wind energy generators, wave power generators, etc., as with solar power generators, the use of natural energy that causes output fluctuations of various periods due to various factors, especially output fluctuations of short periods. The present invention can be applied to the power generation device in general.

  Although the first to third embodiments have been specifically described above, the present invention is not limited to them. Embodiments obtained by appropriately combining the technical means disclosed in the three embodiments described above are also included in the technical scope of the present invention.

  In the above-described embodiments, the configuration illustrated in the accompanying drawings is merely an example, and is not limited thereto, and can be appropriately changed within a range in which the effect of the present invention is exhibited. It is. In addition, various modifications can be made without departing from the scope of the object of the present invention.

  In the description of the above embodiment, each component for realizing the function of the present invention is described as being a different part. However, in actuality, there is a part that can be clearly separated and recognized in this way. It doesn't have to be. The composite self-sustained power generation system that realizes the functions of the above-described embodiments may be configured such that each component for realizing the function is actually configured using different parts, for example, or all the components May be implemented in one part. That is, what kind of mounting form should just have each component as a function.

  In addition, a program for realizing the functions described in the present embodiment is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed to execute processing of each unit. You may go. Here, the “computer system” includes an OS and hardware such as peripheral devices.

  Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used.

  The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory in a computer system serving as a server or a client in that case, and a program that holds a program for a certain period of time are also included. The program may be a program for realizing a part of the above-described functions, or may be a program that can realize the above-described functions in combination with a program already recorded in a computer system.

  The present invention can be used for a composite self-sustained power generation system, a control method for composite self-sustained power generation, and the like.

DESCRIPTION OF SYMBOLS 1A Combined type independent power generation system 1B Combined type independent power generation system 1C Combined type independent power generation system 2 Solar power generation device 3 Power storage device 4 Thermal power generation device 5A Power generation control device 5B Power generation control device 5C Power generation control device 6 DC / DC conversion unit 7 DC / AC conversion unit 8A Charge controller unit 8B Charge controller unit 9A Control unit 9B Control unit 9C Control unit 10 AC / DC conversion unit 11 Reverse power flow control device

Claims (14)

A solar power generation device, a power storage device, a fuel-use power generation device, a power generation control device, and a combined self-sustained power generation system connected to a load,
The power generation control device smoothes short cycle fluctuations of the power generation amount of the solar power generation device using the power storage device, and generates power from the fuel-use power generation device according to the demand power amount of the load. A combined self-sustaining power generation system characterized by supply.   The combined self-sustaining power generation system according to claim 1, wherein the short-term fluctuation of the power generation amount of the solar power generation apparatus is a fluctuation of a period that is difficult to follow in the fuel-use power generation apparatus.   The power generation control device increases the power generation amount of the fuel-use power generation device when the power generation amount of the combined self-sustained power generation system is less than the demand power amount of the load, 3. The combined self-sustaining power generation system according to claim 1, wherein the power generation amount of the fuel-use power generation apparatus is decreased when the amount of power demand is greater than the load demand power amount.   The power generation control device supplies power from the fuel-use power generation device to charge the power storage device when the power storage amount of the power storage device is equal to or lower than a first power storage amount reference value, and stores the power of the power storage device. The composite type according to any one of claims 1 to 3, wherein when the amount becomes equal to or greater than a second storage amount reference value that is larger than the first storage amount reference value, the storage device is discharged. Independent power generation system.   Even if the power generation control device controls the power generation amount of the fuel-use power generation device to a minimum, the power generation control device can reduce the solar power generation device when the power generation amount of the combined self-sustained power generation system is larger than the demand power amount of the load. The combined self-sustained power generation system according to any one of claims 1 to 4, wherein the amount of power output from the power source to the load is limited. The combined self-sustaining power generation system is connected to a power system,
5. The power generation control device according to claim 1, wherein when the power generation amount of the combined self-sustained power generation system is larger than the demand power amount of the load, the surplus power is caused to flow backward to the power system. 6. The combined self-sustaining power generation system according to crab. The power generation control device has a first frequency reference value lower than the standard frequency of the output of the combined self-sustained power generation system, and a second frequency reference value higher than the standard frequency,
When the output frequency from the composite self-sustained power generation system to the load is lower than the first frequency reference value, it is determined that the power generation amount of the composite self-sustained power generation system is less than the demand power amount of the load,
When the output frequency is higher than the second frequency reference value, it is determined that the power generation amount of the combined self-sustained power generation system is larger than the demand power amount of the load,
The composite self-supporting power generation system according to any one of claims 1 to 6. A control method for a combined self-sustaining power generation system that supplies power generated by a solar power generation device and a fuel-use power generation device to a load,
Smoothing short cycle fluctuations in the amount of power generated by the photovoltaic power generation device using a power storage device;
Supplying power from the fuel-use power generator according to the amount of power demand of the load;
A control method for a combined self-sustained power generation system, comprising:   The method for controlling a combined self-sustained power generation system according to claim 8, wherein the short-term fluctuation of the power generation amount of the solar power generation apparatus in the previous period is a fluctuation of the period that is difficult to follow in the fuel-use power generation apparatus. . Increasing the power generation amount of the fuel-use power generation apparatus when the power generation amount of the combined self-sustaining power generation system is less than the demand power amount of the load;
Reducing the power generation amount of the fuel-use power generator when the power generation amount of the combined self-sustaining power generation system is greater than the demand power amount of the load;
10. The control method for a combined self-sustaining power generation system according to claim 8, wherein: When the power storage amount of the power storage device is equal to or less than a first power storage amount reference value, supplying power from the fuel-use power generation device to charge the power storage device;
Discharging from the power storage device when the power storage amount of the power storage device is greater than or equal to a second power storage amount reference value greater than the first power storage amount reference value;
The method for controlling a combined self-sustaining power generation system according to any one of claims 8 to 10, wherein:   Even if the power generation amount of the fuel-based power generation device is controlled to the minimum, when the power generation amount of the combined self-sustained power generation system is larger than the demand power amount of the load, the solar power generation device outputs to the load The method for controlling a combined self-sustaining power generation system according to any one of claims 8 to 11, further comprising a step of limiting the amount of electric power.   When the amount of power generated by the combined self-sustained power generation system is larger than the amount of power demanded by the load, the method includes a step of causing a surplus power to flow backward to an electric power system connected to the composite self-supporting power generation system. Item 12. A control method for a combined self-sustaining power generation system according to any one of Items 8 to 11. When the output frequency from the composite self-sustained power generation system to the load is lower than a first frequency reference value lower than the standard frequency of the output of the composite self-supporting power generation system, the power generation amount of the composite self-supporting power generation system is Determining that it is less than the amount of power demand of the load;
When the output frequency is higher than a second frequency reference value higher than the standard frequency, determining that the power generation amount of the combined self-sustained power generation system is greater than the demand power amount of the load;
14. The method for controlling a combined self-sustained power generation system according to claim 8, wherein