JP2016220396A - Distributed power supply system and distributed power supply system control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a distributed power supply system that can keep an engine generator such as a diesel generator to have a high power generation efficiency while suppressing loss of power generated by the engine generator.SOLUTION: A distributed power supply system 100 includes a natural energy power supply device 110 which has a natural energy power generation device 111 for generating electric power by using natural energy, a power supply circuit 112, a power storage battery 113, and an inverter 114, and outputs power converted by an inverter 114 to a power line to which a load 200 is connected, an engine generator 120 that generates electric power by using an internal combustion engine and outputs the electric power generated by using the internal combustion engine to the power line, and a controller 130 for controlling the output amount of the natural energy power supply device 110 and the output amount of the engine generator 120 so that the output amount of the engine generator 120 is maintained within a limited range.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a distributed power supply system that supplies power to a load.

  Conventionally, a secondary battery is connected between the power generation facility and the load, and the power generation facility is operated at the rated output by compensating for the excess or deficiency between the generated power and the load demand power with the charge and discharge of the secondary battery. Has been proposed (see Patent Document 1).

  In addition, it has been proposed to suppress power fluctuation within a range that can be followed by the governor for the generator by controlling charging / discharging of the power storage unit (see Patent Document 2).

  Further, it has been proposed to charge surplus power from a solar cell and surplus power from a diesel generator and to discharge the charged power as necessary (see Patent Document 3).

JP 2007-82311 A JP 2007-228737 A JP-A-3-74147

  However, in the technique described in Patent Document 1, even when power generation is performed with high fuel efficiency, when power is supplied to the load via the secondary battery, AC-DC conversion, charging, discharging, and DC- A loss occurs in power due to AC conversion or the like.

  In the technique described in Patent Document 2, power fluctuation is suppressed within a range that can be followed by the generator governor, but the power generator may generate power with low power generation efficiency.

  Moreover, in the technique described in Patent Document 3, the power generation amount of the diesel generator is not maintained within a certain range, and the power generation efficiency may be reduced.

  Accordingly, an object of the present invention is to provide a distributed power supply system or the like that can maintain a high power generation efficiency of an engine generator while suppressing a loss of power generated by an engine generator such as a diesel generator. To do.

  In order to achieve the above object, a distributed power supply system according to one aspect of the present invention is a distributed power supply system that supplies power to a load, and a natural energy power generation device that generates power using natural energy; A power supply circuit that generates power of a predetermined voltage from the power generated by the natural energy power generation device, a storage battery that is charged with the power obtained from the power supply circuit, and the charged power is discharged, and the power supply circuit and the storage battery A natural energy power supply device comprising: an inverter that converts electric power obtained from the inverter into AC power; a natural energy power supply device that outputs the power converted by the inverter to a power line connected to the load; and an internal combustion engine An engine generator that generates electric power using the internal combustion engine and outputs the electric power generated using the internal combustion engine to the power line; and An output amount of the natural energy power supply device so that the output amount of the engine generator is maintained within a predetermined limit range as a range for making the power generation efficiency of the generator higher than a predetermined power generation efficiency; and And a controller for controlling the output amount of the engine generator.

  A distributed power system control method according to an aspect of the present invention is a distributed power system control method for supplying power to a load, and the distributed power system uses natural energy to generate power. An energy power generation device, a power supply circuit that generates power of a predetermined voltage from the power generated by the natural energy power generation device, a storage battery in which power obtained from the power supply circuit is charged, and the charged power is discharged, A natural energy power supply device comprising an inverter that converts electric power obtained from the power supply circuit and the storage battery into AC power, and outputs the electric power converted by the inverter to a power line to which the load is connected. And an apparatus for generating electric power using the internal combustion engine and outputting the electric power generated using the internal combustion engine to the power line. The distributed power supply system control method includes the engine generator output within a limit range that is predetermined as a range for making the power generation efficiency of the engine generator higher than a predetermined power generation efficiency. And a control step of controlling the output amount of the natural energy power supply device and the output amount of the engine generator so that the power amount is maintained.

  The distributed power supply system and the like according to one embodiment of the present invention can maintain high power generation efficiency of the engine generator while suppressing loss of power generated by the engine generator such as a diesel generator.

The block diagram which shows the structure of the distributed power supply system in embodiment The graph which shows the output amount of the engine generator in embodiment The graph which shows the power generation efficiency of the engine generator in embodiment The graph which shows the time change of the output amount of the natural energy power supply device and engine generator in embodiment The graph which shows the time change of the output amount of the engine generator in embodiment The graph which shows the time change of the electric power demand amount and electric power supply amount in embodiment The flowchart which shows operation | movement of the natural energy power supply device in embodiment The flowchart which shows operation | movement of the engine generator in embodiment. The flowchart which shows operation | movement of the controller in embodiment Block diagram showing the configuration of the distributed power supply system in the reference example The graph which shows the time change of the output amount of the natural energy power unit and engine generator in a reference example The flowchart which shows operation | movement of the controller in the modification 1 of embodiment. The graph which shows the time change of the output amount of the natural energy power supply device and engine generator in the modification 1 of embodiment. The graph which shows the time change of the output amount of the engine generator in the modification 1 of embodiment. The graph which shows the time change of the remaining capacity in the modification 1 of embodiment. The graph which shows the time change of the electric power generation amount in the modification 2 of embodiment The graph which shows the time change of the output amount of the natural energy power supply device and engine generator in the modification 3 of embodiment. The graph which shows the time change of the electric power demand amount in the modification 3 of embodiment, and an electric power supply amount

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that each of the embodiments described below shows a comprehensive or specific example. Numerical values, shapes, materials, components, arrangement positions and connection forms of components, order of operations, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept are described as arbitrary constituent elements.

(Embodiment)
FIG. 1 is a block diagram showing a distributed power supply system according to the present embodiment. The distributed power supply system 100 shown in FIG. 1 includes a natural energy power supply device 110, an engine generator 120, and a controller 130, and supplies power to a load 200.

  The natural energy power supply device 110 includes a natural energy power generation device 111, a power supply circuit 112, a storage battery 113, and an inverter 114. In addition, the natural energy power supply apparatus 110 outputs power to a power line to which the load 200 is connected.

  The natural energy power generation device 111 generates electric power using natural energy such as sunlight, wind power or geothermal heat. For example, the natural energy power generation device 111 may be a solar cell that generates power using sunlight, or may be a solar power generation device including a solar cell. The amount of power generated by the natural energy power generation device 111 varies depending on the state of natural energy. Therefore, the fluctuation of the power generation amount of the natural energy power generation apparatus 111 is large. In the present embodiment, the natural energy power generation device 111 generates DC power and outputs the generated DC power.

  The power supply circuit 112 is a power supply circuit that generates power of a predetermined voltage, and specifically, a DC power supply circuit that generates DC power of a predetermined voltage. For example, the power supply circuit 112 may be a DC-DC converter that generates DC power having a predetermined voltage by converting DC power into DC power having a predetermined voltage. Further, the power supply circuit 112 may be a charger that suppresses overcurrent and generates DC power of a predetermined voltage in which the overcurrent is suppressed.

  In the present embodiment, the power supply circuit 112 generates DC power (for example, 12 V DC power) having a predetermined voltage from DC power (for example, 24 V DC power) generated by the natural energy power generation device 111.

  The predetermined voltage is not necessarily a constant voltage. The predetermined voltage may be a voltage included in a predetermined voltage range such as a voltage included in a range from 11 V to 13 V, for example.

  The storage battery 113 is a secondary battery for charging and discharging power. The storage battery 113 is charged with power generated by the power supply circuit 112. Further, the power charged in the storage battery 113 is discharged from the storage battery 113. The storage battery 113 has a role for accumulating the electric power generated by the natural energy power generation device 111 having a large fluctuation in the amount of power generation and stably supplying the electric power according to demand.

  The inverter 114 converts electric power into AC electric power. In the present embodiment, inverter 114 converts power (DC power) obtained from power supply circuit 112 and storage battery 113 into AC power, and outputs AC power to a power line to which load 200 is connected.

  For example, when the power generated by the power supply circuit 112 is larger than the power to be converted by the inverter 114, the power to be converted by the inverter 114 among the power generated by the power supply circuit 112 is input to the inverter 114. The remaining power is charged in the storage battery 113. When the power generated by the power supply circuit 112 is smaller than the power to be converted by the inverter 114, the power corresponding to the shortage is discharged from the storage battery 113, and the power generated by the power supply circuit 112 and the storage battery 113 are discharged. Power is input to the inverter 114.

  When the power generated by the power supply circuit 112 is equal to the power to be converted by the inverter 114, the power generated by the power supply circuit 112 is input to the inverter 114. The power input to the inverter 114 is converted into AC power and output.

  Further, the inverter 114 may be a bidirectional inverter. In this case, the inverter 114 converts power (AC power) obtained from the power line to which the load 200 is connected into DC power.

  For example, the engine generator 120 is connected to the power line to which the load 200 is connected, and the inverter 114 converts the power obtained from the engine generator 120 via the power line into DC power. The inverter 114 charges the storage battery 113 with DC power. Thereby, the surplus power of the engine generator 120 with respect to the demand power of the load 200 is charged in the storage battery 113.

  Further, the inverter 114 may operate as a voltage source that generates a voltage and outputs electric power of the generated voltage. That is, the inverter 114 may operate as a voltage source inverter. Thereby, the inverter 114 can perform a self-sustained operation without depending on other electric power systems.

  Further, the inverter 114 may operate as a virtual synchronous generator by outputting electric power by simulating the output characteristics of the synchronous generator. Specifically, the inverter 114 calculates the phase of the rotor in the virtual synchronous generator based on the output amount of the inverter 114, and outputs AC power using the calculated phase as the phase of the AC voltage.

  More specifically, the inverter 114 calculates the difference between the output amount of power that is actually output by the inverter 114 and the output amount of power that the inverter 114 should output, as a change in the angular velocity of the rotor in the virtual synchronous generator. The angular velocity of the rotor is calculated using the value indicating the quantity. Then, the inverter 114 integrates the angular velocity of the rotor and calculates the angular phase of the rotor. Inverter 114 uses the calculated angular phase as the phase of the AC power voltage.

  Thereby, the inverter 114 can operate like a synchronous generator. In parallel operation of the inverter 114 and the engine generator 120, the inverter 114 can output power stably in synchronization with the engine generator 120.

  Moreover, the inverter 114 may output electric power according to droop control. That is, the inverter 114 may output AC power according to a correspondence relationship between an increase in output amount and a decrease in frequency or voltage (at least one of frequency and voltage). Specifically, the inverter 114 may adapt the output amount and the frequency or voltage to a predetermined correspondence relationship. More specifically, the inverter 114 may match the output amount and the frequency or voltage with a predetermined correspondence.

  For example, the engine generator 120 may have an output characteristic in which the frequency or voltage of the AC power output from the engine generator 120 decreases as the amount of AC power output from the engine generator 120 increases. In this case, the inverter 114 may detect the frequency or voltage of the AC power output from the engine generator 120 from the power line to which the engine generator 120 is connected. Then, the inverter 114 may output electric power corresponding to the output amount associated with the detected frequency or voltage.

  As a result, the output amount of the inverter 114 increases as the output amount of the engine generator 120 increases. Therefore, the inverter 114 and the engine generator 120 can output power in cooperation with the power demand amount of the load 200.

  Further, for example, the engine generator 120 may have an output characteristic in which the output amount of the AC power output from the engine generator 120 increases as the frequency or voltage of the AC power output from the engine generator 120 decreases. is there. In this case, the inverter 114 may decrease the frequency or voltage of the AC power output from the inverter 114 as the output amount of the AC power output from the inverter 114 increases.

  As a result, the output amount of the engine generator 120 increases as the output amount of the inverter 114 increases. Therefore, the inverter 114 and the engine generator 120 can output power in cooperation with the power demand amount of the load 200.

  That is, the inverter 114 can adjust the output amount and the voltage or frequency based on a predetermined correspondence by droop control, and can output power in cooperation with the engine generator 120. In the above description, an increase in output amount is associated with a decrease in frequency or voltage, but an increase in output amount may be associated with an increase in frequency or voltage.

  The engine generator 120 generates electric power using an internal combustion engine (not shown). For example, the engine generator 120 is a diesel engine generator, a gas engine generator, a gas turbine engine generator, or the like. The engine generator 120 outputs power to the power line to which the load 200 is connected.

  The controller 130 controls the output amount of the natural energy power supply device 110 and the output amount of the engine generator 120. That is, the controller 130 adjusts the output amount of the natural energy power supply device 110 and the output amount of the engine generator 120. Then, the controller 130 adapts the total output amount that is the sum of the output amount of the natural energy power supply device 110 and the output amount of the engine generator 120 to the power demand amount of the load 200.

  For example, the controller 130 controls the output amount of the natural energy power supply device 110 and the output amount of the engine generator 120 by transmitting a power command value to the natural energy power supply device 110 and the engine generator 120. .

  Specifically, the controller 130 transmits an output command value indicating the output amount of the natural energy power supply device 110 to the natural energy power supply device 110 via the communication line. The natural energy power supply device 110 receives the output command value and outputs power according to the output amount indicated by the output command value. Thereby, the controller 130 controls the output amount of the natural energy power supply device 110.

  Similarly, the controller 130 transmits an output command value indicating the output amount of the engine generator 120 to the engine generator 120 via the communication line. The engine generator 120 receives the output command value and outputs power according to the output amount indicated by the output command value. Thereby, the controller 130 controls the output amount of the engine generator 120.

  The controller 130 may transmit an output command value to the inverter 114 included in the natural energy power supply device 110. Then, inverter 114 may receive the output command value and output power according to the output amount indicated by the output command value. Thereby, the controller 130 can control the output amount of the natural energy power supply device 110.

  The controller 130 may control the other by controlling one of the output amount of the natural energy power supply device 110 and the output amount of the engine generator 120.

  For example, the controller 130 controls the output amount of the natural energy power supply device 110 by transmitting an output command value to the natural energy power supply device 110. Then, the engine generator 120 outputs power corresponding to the difference between the output amount (power supply amount) of the natural energy power supply device 110 and the power demand amount of the load 200. Specifically, the engine generator 120 outputs a shortage of electric power that has not been applied to the electric power demand of the load 200 with the electric power supply amount of the natural energy power supply device 110.

  Based on the above operation, the controller 130 can control the output amount of the engine generator 120 by controlling the output amount of the natural energy power supply device 110.

  Furthermore, the controller 130 maintains the output amount of the natural energy power supply device 110 within the allowable output range of the natural energy power supply device 110. For example, the allowable output range of the natural energy power supply device 110 is determined based on the capabilities of the storage battery 113 and the inverter 114. In addition, the controller 130 maintains the output amount of the engine generator 120 within a predetermined limit range as a range in which high power generation efficiency can be obtained in the engine generator 120. Thereby, in the engine generator 120, the state where power generation efficiency is high is maintained.

  The controller 130 may be a dedicated or general-purpose information processing circuit, for example. The controller 130 may be a processor or a computer including a processor.

  The load 200 is one or more electric devices that consume power. The load 200 is connected to a power line to which the natural energy power supply device 110 and the engine generator 120 are connected. The load 200 is supplied with electric power output from the natural energy power supply device 110 and the engine generator 120. Regarding the power demand amount of the load 200, basically, a power demand amount larger than the lower limit of the limit range for the output amount of the engine generator 120 is assumed.

  FIG. 2 is a graph showing the output amount of the engine generator 120 shown in FIG. The maximum output amount and the minimum output amount are predetermined as ratings for the engine generator 120. For example, the maximum output amount is the maximum output amount in the output allowable range, and the minimum output amount is the minimum output amount in the output allowable range. In the present embodiment, the maximum output amount is 10 kW, and the minimum output amount is 0 kW. The maximum output amount and the minimum output amount of the engine generator 120 are not limited to this example, and may be different values.

  The limit range shown in FIG. 2 is a range in which the controller 130 maintains the output amount of the engine generator 120. For example, the upper limit of the limit range is lower than the maximum output amount, and the lower limit of the limit range is higher than the minimum output amount.

  Specifically, the limited range is a range that is predetermined as a range for making the power generation efficiency of the engine generator 120 higher than a predetermined power generation efficiency. In other words, it is a range in which it is assumed that the power generation efficiency higher than the predetermined power generation efficiency can be obtained in the engine generator 120. The predetermined power generation efficiency may be an average power generation efficiency of the engine generator 120, for example. The predetermined power generation efficiency may not be determined as a specific numerical value, and may be, for example, power generation efficiency at 60% of the maximum output amount.

  Further, the limited range may be a range in which the power generation efficiency is estimated to be high based on the maximum output amount. Specifically, when the power generation efficiency of the engine generator 120 is assumed to be higher than a predetermined power generation efficiency (for example, power generation efficiency at the maximum output amount) in a range from 60% to 80% of the maximum output amount, The limit range may be a range from 60% to 80% of the maximum output amount. Further, the limit range may be a range defined as the vicinity of the output amount at which the maximum power generation efficiency is obtained, such as 10% before and after the output amount at which the maximum power generation efficiency is obtained.

  In the present embodiment, the upper limit of the limit range is 8 kW, and the lower limit of the limit range is 6 kW. The upper and lower limits of the limit range are not limited to this example, and may be different values.

  FIG. 3 is a graph showing the power generation efficiency of the engine generator 120 shown in FIG. In the present embodiment, the power generation efficiency of the engine generator 120 increases as the output amount of the engine generator 120 increases from 0 kW. The maximum power generation efficiency can be obtained at an output amount of 7 kW. Thereafter, the power generation efficiency decreases as the output amount increases. The power generation efficiency at the maximum output amount of 10 kW is about 30%.

  In the present embodiment, a power generation efficiency of 40% or more can be obtained with an output amount of 6 kW to 8 kW included in the limit range. Thus, the limit range is determined so that high power generation efficiency can be obtained in the engine generator 120.

  FIG. 4 is a graph showing temporal changes in the output amounts of the natural energy power supply device 110 and the engine generator 120 shown in FIG. In FIG. 4, the output amount of the engine generator 120 is added to the output amount of the natural energy power supply device 110. That is, FIG. 4 shows the total output amount of the output amount of the natural energy power supply device 110 and the output amount of the engine generator 120. The load 200 is supplied with electric power corresponding to the total output amount.

  The controller 130 determines the output amount of the natural energy power supply device 110 and the engine so that the total output amount of the output amount of the natural energy power supply device 110 and the output amount of the engine generator 120 matches the power demand amount of the load 200. The output amount of the generator 120 is controlled. Further, the controller 130 maintains the output amount of the natural energy power supply device 110 within the output allowable range of the natural energy power supply device 110, and the engine generator falls within a predetermined limit range in which high power generation efficiency can be obtained in the engine generator 120. The output amount of 120 is maintained.

  In the present embodiment, the upper limit of the allowable output range of the natural energy power supply device 110 is 2 kW, and the lower limit of the allowable output range of the natural energy power supply device 110 is 0 kW. Therefore, the controller 130 maintains the output amount of the natural energy power supply device 110 within the range from 0 kW to 2 kW. The upper and lower limits of the output allowable range of the natural energy power supply device 110 are not limited to this example, and may be different values.

  Further, when the inverter 114 is a bidirectional inverter, a negative output amount may be used as the output amount of the natural energy power supply device 110. The negative output amount corresponds to the amount of power that the inverter 114 converts from AC power to DC power, and corresponds to the amount of power that the inverter 114 charges to the storage battery 113. Therefore, when the inverter 114 is a bidirectional inverter, the lower limit of the output allowable range of the natural energy power supply device 110 may be a negative output amount.

  FIG. 5 is a graph showing changes over time in the output amount of the engine generator 120 shown in FIG. The output amount of the engine generator 120 shown in FIG. 5 corresponds to the output amount of the engine generator 120 shown in FIG. As shown in FIG. 5, the output amount of the engine generator 120 is maintained within a predetermined limit range.

  That is, the controller 130 maintains the output amount of the engine generator 120 within the limit range from 6 kW to 8 kW.

  6 shows the power demand amount of the load 200 shown in FIG. 1, the power supply amount of the natural energy power supply device 110 shown in FIG. 1, and the power supply amount of the engine generator 120 shown in FIG. It is a graph which shows a time change. The power supply amount of the natural energy power supply device 110 shown in FIG. 6 corresponds to the output amount of the natural energy power supply device 110 shown in FIG. The power supply amount of the engine generator 120 shown in FIG. 6 corresponds to the output amount of the engine generator 120 shown in FIG.

  6 corresponds to the sum of the power supply amount of the natural energy power supply apparatus 110 and the power supply amount of the engine generator 120. That is, the power demand amount of the load 200 corresponds to the total output amount of the output amount of the natural energy power supply device 110 and the output amount of the engine generator 120.

  As shown in FIG. 6, the controller 130 maintains the output amount (power supply amount) of the engine generator 120 within a predetermined limit range. In addition, the controller 130 maintains the output amount (power supply amount) of the natural energy power supply device 110 within the output allowable range of the natural energy power supply device 110. Then, the controller 130 adapts the total output amount of the output amount of the natural energy power supply device 110 and the output amount of the engine generator 120 to the power demand amount of the load 200.

  For example, the controller 130 maintains the output amount of the natural energy power supply device 110 within a range from 0 kW to 2 kW, and maintains the output amount of the engine generator 120 within a range from 6 kW to 8 kW. Then, the controller 130 adapts the total output amount of the output amount of the engine generator 120 and the output amount of the natural energy power supply apparatus 110 to the power demand amount of the load 200 in the range from 6 kW to 10 kW.

  The controller 130 distributes the total output amount with respect to the power demand amount of the load 200 to the natural energy power supply device 110 and the engine generator 120 according to the output allowable range of the natural energy power supply device 110 and the limit range of the engine generator 120. For example, in the example of the present embodiment, the power demand amount of the load 200 is expressed by L (kW), the output amount of the natural energy power supply device 110 is expressed by R (kW), and the output amount of the engine generator 120 is When expressed in E (kW), R and E are derived from Equation 1 below.

<Formula 1>
R = (L-6) / 2
E = (L−6) / 2 + 6
(However, 6 ≦ L ≦ 10)

  Furthermore, when the lower limit of the output allowable range of the natural energy power supply device 110 is expressed as Ra, the upper limit is Rb, the lower limit of the limit range of the engine generator 120 is expressed as Ea, and the upper limit is expressed as Eb, Expression 1 is expressed by Expression 2 below. It is expressed as follows.

<Formula 2>
R = (L−Ra−Ea) × (Rb−Ra) / (Rb−Ra + Eb−Ea) + Ra
E = (L−Ra−Ea) × (Eb−Ea) / (Rb−Ra + Eb−Ea) + Ea
(However, Ra + Ea ≦ L ≦ Rb + Eb)

  The controller 130 distributes the total output amount with respect to the power demand amount of the load 200 to the natural energy power supply device 110 and the engine generator 120 based on the above formula.

  As a result, the controller 130 maintains the output amount of the natural energy power supply device 110 within the allowable output range, and maintains the output amount of the engine generator 120 within the limit range, while reducing the total output amount to the power demand amount of the load 200. Can be adapted. Therefore, the controller 130 can maintain the power generation efficiency of the engine generator 120 in a high state.

  Moreover, the fluctuation | variation of the output amount of the natural energy power supply device 110 and the fluctuation | variation of the output amount of the engine generator 120 can be suppressed with respect to the fluctuation | variation of the electric power demand amount of the load 200. FIG. Therefore, the controller 130 can suppress deterioration of the storage battery 113 and the like.

  The above distribution method is an example, and other distribution methods may be applied. For example, the controller 130 may cause the natural energy power supply device 110 to output excess power only when the power demand of the load 200 exceeds the limit range of the engine generator 120. Thereby, the use frequency of the storage battery 113 decreases and deterioration of the storage battery 113 is suppressed.

  Further, the controller 130 may keep the output amount of the engine generator 120 constant and cause the output amount of the natural energy power supply device 110 to follow the fluctuation of the power demand amount of the load 200. The controller 130 may change the output amount of the engine generator 120 only when the power demand amount of the load 200 changes beyond the allowable output range of the natural energy power supply device 110. Thereby, the controller 130 can maintain the power generation efficiency of the engine generator 120 in a higher state when the fluctuation of the power demand amount of the load 200 is small.

  In the present embodiment, it is assumed that the power demand of load 200 is within the range covered by both the allowable output range of natural energy power supply device 110 and the limited range of engine generator 120. When the power demand of the load 200 is within this assumed range, the power generation efficiency of the engine generator 120 is maintained at a high level, and the loss of power generated by the engine generator 120 is suppressed.

  When the power demand amount of the load 200 is not within the assumed range, the controller 130 may not maintain the output amount of the engine generator 120 within the limit range. That is, in this case, the controller 130 may cause the engine generator 120 to output power corresponding to the output amount within the allowable output range of the engine generator 120 without being within the limit range.

  Thereby, the controller 130 can change the power supply amount largely with respect to the large change in the power demand amount of the load 200.

  Next, operations of the natural energy power supply device 110, the engine generator 120, and the controller 130 included in the distributed power supply system 100 illustrated in FIG. 1 will be described with reference to FIGS.

  FIG. 7 is a flowchart showing the operation of the natural energy power supply apparatus 110 shown in FIG.

  First, the natural energy generator 111 generates electric power using natural energy (S111). Next, the power supply circuit 112 generates power of a predetermined voltage from the power generated by the natural energy power generation device 111 (S112).

  Next, the power generated by the power supply circuit 112 is charged in the storage battery 113, and the charged power is discharged from the storage battery 113 (S113). The inverter 114 converts the power discharged from the storage battery 113 into AC power (S114). The power generated by the power supply circuit 112 may be converted into AC power by the inverter 114 without charging the storage battery 113. Then, the inverter 114 outputs the converted power to the power line to which the load 200 is connected (S115).

  FIG. 8 is a flowchart showing the operation of the engine generator 120 shown in FIG. First, the engine generator 120 generates electric power using the internal combustion engine provided in the engine generator 120 (S121). Then, the engine generator 120 outputs the generated power to the power line to which the load 200 is connected (S122).

  FIG. 9 is a flowchart showing the operation of the controller 130 shown in FIG. The controller 130 controls the output amount of the natural energy power supply device 110 and the output amount of the engine generator 120 (S131). That is, the controller 130 adjusts the output amount of the natural energy power supply device 110 and the output amount of the engine generator 120.

  Then, the controller 130 maintains the output amount of the natural energy power supply device 110 within the output allowable range of the natural energy power supply device 110. Further, the controller 130 maintains the output amount of the engine generator 120 within a predetermined limit range (S131). Then, the controller 130 adapts the total output amount of the output amount of the natural energy power supply device 110 and the output amount of the engine generator 120 to the power demand amount of the load 200.

  The power demand amount of the load 200 may reflect the power supply amount of another power source different from the natural energy power supply device 110 and the engine generator 120. That is, when power is supplied to the load 200 from another power source, the power supply amount of the other power source may be subtracted from the power demand amount of the load 200. In this case, the controller 130 adapts the total output amount of the natural energy power supply device 110 and the engine generator 120 to the power demand amount obtained by subtracting the power supply amount of the other power source.

  In the present embodiment, natural energy power supply device 110 and engine generator 120 are connected to load 200 in parallel. Then, by controlling the output amount of the natural energy power supply device 110 and the output amount of the engine generator 120, the output amount of the engine generator 120 is maintained within the limit range. Thereby, there is little loss of the electric power generated with the engine generator 120, and the power generation efficiency of the engine generator 120 is maintained high.

  Next, an example different from the example in the present embodiment will be described as a reference example. The following reference example is an example in which high power generation efficiency cannot be obtained.

  FIG. 10 is a block diagram illustrating a distributed power supply system according to a reference example. The distributed power supply system 100a shown in FIG. 10 includes a natural energy power supply device 110a, an engine generator 120a, a controller 130a, and a switch 140a. The natural energy power supply device 110a, the engine generator 120a, and the controller 130a are components corresponding to the natural energy power supply device 110, the engine generator 120, and the controller 130 in FIG.

  The natural energy power supply device 110a includes a natural energy power generation device 111a, a power supply circuit 112a, a storage battery 113a, and an inverter 114a. The natural energy power generation device 111a, the power supply circuit 112a, the storage battery 113a, and the inverter 114a are components corresponding to the natural energy power generation device 111, the power supply circuit 112, the storage battery 113, and the inverter 114 in FIG.

  The distributed power supply system 100a in the present reference example switches between power supply from the natural energy power supply apparatus 110a to the load 200 and power supply from the engine generator 120a to the load 200 by the switch 140a.

  For example, when the amount of power generated by the natural energy power generation apparatus 111a is large, or when the remaining capacity of the storage battery 113a is large, the natural energy power supply apparatus 110a supplies power to the load 200. Conversely, when the amount of power generated by the natural energy generator 111a is small and the remaining capacity of the storage battery 113a is small, the engine generator 120a supplies power to the load 200.

  Then, while the engine generator 120a supplies power to the load 200, the power supply circuit 112a charges the storage battery 113a with the power generated by the natural energy power generation device 111a. And if the remaining capacity of the storage battery 113a becomes large, the switch 140a will switch the electric power supply source to the load 200 from the engine generator 120a to the natural energy power supply device 110a.

  That is, when the natural energy power supply device 110 a can supply sufficient power to the load 200, the natural energy power supply device 110 a supplies power to the load 200. When the natural energy power supply device 110 a cannot supply sufficient power to the load 200, the natural energy power supply device 110 a accumulates power to be supplied to the load 200. Meanwhile, the engine generator 120a supplies power to the load 200.

  Thereby, the natural energy power supply device 110a and the engine generator 120a can cooperate with each other to supply power to the load 200.

  FIG. 11 is a graph showing temporal changes in the output amounts of the natural energy power supply device 110a and the engine generator 120a shown in FIG. In this reference example, electric power is supplied from one of the natural energy power supply device 110a and the engine generator 120a. That is, the natural energy power supply device 110a and the engine generator 120a do not supply power at the same time. Therefore, the amount of power supplied to the load 200 is reduced.

  Further, the natural energy power supply device 110a and the engine generator 120a cannot share the power supply to the load 200. Therefore, it is difficult to control the output amount of the natural energy power supply device 110a within the allowable output range and to control the output amount of the engine generator 120a within a predetermined limit range.

  Further, a momentary power failure occurs in switching between power supply from the natural energy power supply device 110a to the load 200 and power supply from the engine generator 120a to the load 200.

  As described above, in the distributed power supply system 100a of the present reference example, the power generation efficiency of the engine generator 120a is not maintained in a high state. In addition, sufficient power is not supplied to the load 200. Furthermore, a momentary power failure occurs at the time of switching.

  On the other hand, in the distributed power supply system 100 of the present embodiment, the power generation efficiency of the engine generator 120 is maintained at a high level. In addition, sufficient power is supplied to the load 200. Furthermore, there is no instantaneous interruption associated with switching.

  Next, a plurality of modifications of the present embodiment will be described. In a plurality of modifications described below, some operations are changed with respect to the present embodiment.

(Modification 1)
First, Modification 1 will be described. The basic configuration of this modification is the same as the configuration of the distributed power supply system 100 shown in FIG. Therefore, the configuration of the distributed power supply system 100 shown in FIG.

  In the present modification, the output amount of the engine generator 120 is maintained within the limit range only when a predetermined condition is satisfied. When the predetermined condition is not satisfied, the output amount of the engine generator 120 is not maintained within the limit range. That is, the restriction is released.

  FIG. 12 is a flowchart showing the operation of the controller 130 in this modification. First, the controller 130 acquires an evaluation target value (S141). The evaluation target value is, for example, the remaining capacity of the storage battery 113 or the amount of power generated by the natural energy power generation device 111.

  Specifically, in this modification, the controller 130 acquires the remaining capacity of the storage battery 113 as an evaluation target value. The remaining capacity of the storage battery 113 corresponds to the state of charge (SOC: State Of Charge) of the storage battery 113.

  For example, the storage battery 113 or the natural energy power supply device 110 measures the remaining capacity of the storage battery 113 based on the charge / discharge amount of the storage battery 113. Alternatively, the storage battery 113 or the natural energy power supply device 110 may measure the remaining capacity of the storage battery 113 based on the voltage of the storage battery 113. The controller 130 communicates with the storage battery 113 or the natural energy power supply device 110 to acquire the remaining capacity of the storage battery 113.

  Next, the controller 130 determines whether or not the evaluation target value satisfies a predetermined condition (S142). Specifically, in this modification, the controller 130 determines whether or not the remaining capacity of the storage battery 113 satisfies a predetermined condition. More specifically, the predetermined condition is that the remaining capacity of the storage battery 113 is larger than the predetermined remaining capacity.

  When the evaluation target value satisfies the predetermined condition (Yes in S142), the controller 130 maintains the output amount of the engine generator 120 within the predetermined limit range (S143). This operation is the same as S131 in FIG.

  On the other hand, when the evaluation target value does not satisfy the predetermined condition (No in S142), the controller 130 does not maintain the output amount of the engine generator 120 within the predetermined limit range. In this case, the controller 130 reduces the output amount of the natural energy power supply device 110 (S144).

  For example, when the evaluation target value does not satisfy a predetermined condition, the controller 130 reduces the output amount of the natural energy power supply device 110 by stopping the output of the natural energy power supply device 110. Specifically, the controller 130 stops the output of the natural energy power supply device 110 when the remaining capacity of the storage battery 113 is not larger than a predetermined remaining capacity.

  That is, when it is assumed that the natural energy power supply device 110 can supply sufficient power to the load 200, the natural energy power supply device 110 supplies power to the load 200. When it is assumed that the natural energy power supply device 110 cannot supply sufficient power to the load 200, the natural energy power supply device 110 stops supplying power to the load 200 and supplies it to the load 200. Accumulate power for. Meanwhile, the engine generator 120 supplies power to the load 200 without being limited to the limited range.

  For example, when the remaining capacity of the storage battery 113 is small, it is assumed that the natural energy power supply device 110 cannot supply sufficient power to the load 200. Moreover, when the remaining capacity of the storage battery 113 is small, the storage battery 113 may deteriorate due to overdischarge.

  Therefore, in this case, the controller 130 stops the power supply from the natural energy power supply device 110 to the load 200. Instead, the controller 130 releases the restriction on the output amount of the engine generator 120 and increases the output amount of the engine generator 120. Thereby, sufficient electric power is supplied to the load 200.

  FIG. 13 is a graph showing temporal changes in the output amounts of the natural energy power supply device 110 and the engine generator 120 shown in FIG. In this example, the period from time T1 to time T2 is a period in which the evaluation target value does not satisfy a predetermined condition. For example, during this period, the remaining capacity of the storage battery 113 is less than or equal to a predetermined remaining capacity. Therefore, during this period, the output amount of the natural energy power supply device 110 is reduced.

  Specifically, in the period from time T1 to time T2, the controller 130 stops the output of the natural energy power supply device 110. Instead, the controller 130 releases the restriction on the output amount of the engine generator 120 and increases the output amount of the engine generator 120.

  FIG. 14 is a graph showing the change over time of the output amount of the engine generator 120 shown in FIG. The output amount of the engine generator 120 shown in FIG. 14 corresponds to the output amount of the engine generator 120 shown in FIG. As described above, the period from time T1 to time T2 is a period in which the evaluation target value does not satisfy the predetermined condition. During this period, the restriction on the output amount of the engine generator 120 is released.

  In the example of FIG. 14, in particular, in the first half of the period from time T1 to time T2, the electric power is output from the engine generator 120 exceeding the limit range. Thereby, sufficient electric power is supplied to the load 200.

  FIG. 15 is a graph showing the change over time of the remaining capacity of the storage battery 113 shown in FIG. In the present modification, the remaining capacity of the storage battery 113 is used as an evaluation target value for determining whether or not the output amount of the engine generator 120 is maintained within the limit range. In FIG. 15, the remaining capacity of the storage battery 113 is expressed in a charged state.

  For example, electric power is supplied from the natural energy power supply device 110 to the load 200 until time T1. With this power supply, the remaining capacity of the storage battery 113 decreases. And at time T1, since the remaining capacity of the storage battery 113 became 50% or less, the power supply from the natural energy power supply device 110 to the load 200 is stopped.

  After the power supply is stopped, the remaining capacity of the storage battery 113 is increased by the power generated by the natural energy power generation device 111. And at time T2, since the remaining capacity of the storage battery 113 became larger than 75%, the electric power supply from the natural energy power supply device 110 to the load 200 is restarted.

  In this example, when power is supplied from the natural energy power supply device 110 to the load 200, 50% is used as a threshold for the remaining capacity of the storage battery 113. In addition, when power is not supplied from the natural energy power supply device 110 to the load 200, 75% is used as a threshold for the remaining capacity of the storage battery 113. Thus, the threshold for the remaining capacity of the storage battery 113 may be changed according to the situation. The frequency of occurrence of switching between restriction and release is suppressed, and the power supply operation is stably performed.

  In this modification, when a predetermined condition is satisfied, the output amount of the engine generator 120 is limited, and when the predetermined condition is not satisfied, the restriction on the output amount of the engine generator 120 is released. In particular, in this modification, when the remaining capacity of the storage battery 113 satisfies a predetermined condition, the output amount of the engine generator 120 is limited, and when the remaining capacity of the storage battery 113 does not satisfy the predetermined condition, The restriction on the output amount is released.

  Therefore, when it is assumed that sufficient power can be supplied from the natural energy power supply device 110, the output amount of the engine generator 120 is limited. On the other hand, when it is assumed that sufficient power cannot be supplied from the natural energy power supply device 110, the restriction on the output amount of the engine generator 120 is lifted.

  The distributed power supply system 100 according to the present modification limits the output amount of the engine generator 120 within a range of high power generation efficiency, and adaptively releases the restriction based on the state of the natural energy power supply device 110, thereby reducing the load. Sufficient power can be supplied to 200.

  The predetermined condition for the remaining capacity of the storage battery 113 is not limited to the condition that the remaining capacity of the storage battery 113 is larger than a predetermined threshold (lower limit). The predetermined condition for the remaining capacity of the storage battery 113 may be a condition that the remaining capacity of the storage battery 113 is smaller than a predetermined threshold (upper limit).

  That is, when the remaining capacity of the storage battery 113 is smaller than a predetermined threshold (upper limit), the output amount of the engine generator 120 may be maintained within the limit range. And when the remaining capacity of the storage battery 113 is more than a predetermined threshold value (upper limit), the output amount of the engine generator 120 may not be maintained within the limit range.

  Thereby, for example, when the natural energy power supply device 110 can supply sufficient power, the controller 130 can make the output amount of the engine generator 120 smaller than the lower limit of the limit range. Thereby, the controller 130 can suppress the consumption of fuel in the engine generator 120.

(Modification 2)
Next, Modification 2 will be described. The basic configuration of this modification is the same as the configuration of the distributed power supply system 100 shown in FIG. Therefore, the configuration of the distributed power supply system 100 shown in FIG. The basic operation of this modification is the same as that of Modification 1 shown in FIGS. In this modification, the power generation amount of the natural energy power generation device 111 is used as the evaluation target value.

  Specifically, in FIG. 12, when the controller 130 acquires the evaluation target value (S141), the controller 130 acquires the power generation amount of the natural energy power generation apparatus 111 as the evaluation target value. For example, the natural energy power generation apparatus 111 or the natural energy power supply apparatus 110 measures the power generation amount of the natural energy power generation apparatus 111 using a power sensor. The controller 130 communicates with the natural energy power generation apparatus 111 or the natural energy power supply apparatus 110 to acquire the power generation amount of the natural energy power generation apparatus 111.

  Alternatively, in the case where the natural energy power generation device 111 is a solar power generation device that generates power using sunlight, the controller 130 uses the solar energy generation device based on the solar radiation amount or the date (at least one of the solar radiation amount and the date). A power generation amount of 111 may be predicted. For example, the controller 130 measures the amount of solar radiation via a solar radiation sensor. When the measured amount of solar radiation is large, the controller 130 may predict that the amount of power generated by the natural energy power generation device 111 is large.

  Further, for example, based on the date, the controller 130 may predict that the amount of power generated by the natural energy power generation device 111 is large in summer, and may predict that the amount of power generation of the natural energy power generation device 111 is small in winter.

  Then, the controller 130 determines whether or not the power generation amount of the natural energy power generation device 111 satisfies the predetermined condition in the determination of whether or not the evaluation target value satisfies the predetermined condition (S142). More specifically, the predetermined condition is that the power generation amount of the natural energy power generation apparatus 111 is larger than the predetermined power generation amount.

  When the power generation amount of the natural energy power generation device 111 is small, it is assumed that the remaining capacity of the storage battery 113 is also small. Therefore, it is assumed that the natural energy power supply device 110 cannot supply sufficient power to the load 200.

  Therefore, when the power generation amount of the natural energy power generation device 111 is equal to or less than the predetermined power generation amount, the controller 130 reduces the output amount of the natural energy power supply device 110 (S144). Basically, in this case, the controller 130 stops the output of the natural energy power supply device 110. In this case, the controller 130 does not limit the output amount of the engine generator 120 within the limit range. As a result, the output (power supply) of the engine generator 120 is applied to the power demand of the load 200.

  On the other hand, when the power generation amount of the natural energy power generation device 111 is large, it is assumed that the remaining capacity of the storage battery 113 is also large. Therefore, it is assumed that the natural energy power supply device 110 can supply sufficient power to the load 200.

  Therefore, when the power generation amount of the natural energy power generation device 111 is larger than the predetermined power generation amount, the controller 130 causes the natural energy power supply device 110 to output power and keeps the output amount of the engine generator 120 within the limit range. (S143). Thereby, high power generation efficiency is maintained in the engine generator 120.

  FIG. 16 is a graph showing the change over time in the amount of power generated by the natural energy power generation device 111 shown in FIG. The power generation amount shown in FIG. 16 may be a measured power generation amount or a predicted power generation amount. In the example of FIG. 16, 1 kW is used as the threshold value.

  For example, the power generation amount of the natural energy power generation device 111 is greater than 1 kW until time T1. Therefore, until time T1, the controller 130 causes the natural energy power supply device 110 to output power and maintains the output amount of the engine generator 120 within the limit range.

  In the period from time T1 to time T2, the amount of power generated by the natural energy power generation device 111 is 1 kW or less. Therefore, in the period from time T1 to time T2, the controller 130 stops the output of the natural energy power supply device 110 and releases the restriction on the output amount of the engine generator 120.

  In the period after time T2, the amount of power generated by the natural energy power generation apparatus 111 is greater than 1 kW. Therefore, in the period after time T2, the controller 130 causes the natural energy power supply device 110 to output power and maintains the output amount of the engine generator 120 within the limit range.

  As described above, in the example of FIG. 16, 1 kW is used as the threshold value. The threshold value is not limited to this example, and may be another value. Further, like the threshold described in FIG. 15, the threshold may be changed according to the situation.

  In this modification, when the power generation amount of the natural energy power generation device 111 satisfies a predetermined condition, the output amount of the engine generator 120 is limited, and when the power generation amount of the natural energy power generation device 111 does not satisfy the predetermined condition, the engine The restriction on the output amount of the generator 120 is released.

  Therefore, when it is assumed that sufficient power can be supplied from the natural energy power supply device 110, the output amount of the engine generator 120 is limited. On the other hand, when it is assumed that sufficient power cannot be supplied from the natural energy power supply device 110, the restriction on the output amount of the engine generator 120 is lifted.

  Similar to the first modification, the distributed power supply system 100 according to the present modification limits the output amount of the engine generator 120 within a range of high power generation efficiency, and adaptively limits the output based on the state of the natural energy power supply device 110. Is released. Thereby, sufficient electric power is supplied to the load 200.

  Even when the remaining capacity of the storage battery 113 is small, the amount of power generated by the natural energy power generation device 111 may be large. In such a case, the natural energy power supply device 110 may be able to sufficiently supply power to the load 200. Therefore, in such a case, the distributed power supply system 100 according to the present modification maintains the power generation efficiency of the engine generator 120 in a high state by maintaining the output amount of the engine generator 120 within a predetermined limit range. be able to.

  Note that the predetermined condition for the power generation amount of the natural energy power generation device 111 is not limited to the condition that the power generation amount of the natural energy power generation device 111 is larger than a predetermined threshold (lower limit). The predetermined condition for the power generation amount of the natural energy power generation device 111 may be a condition that the power generation amount of the natural energy power generation device 111 is smaller than a predetermined threshold (upper limit).

  That is, when the power generation amount of the natural energy power generation apparatus 111 is smaller than a predetermined threshold (upper limit), the output amount of the engine generator 120 may be maintained within the limit range. And when the electric power generation amount of the natural energy power generation apparatus 111 is more than a predetermined threshold value (upper limit), the output amount of the engine generator 120 may not be maintained within the limit range.

  Thereby, for example, when the natural energy power supply device 110 can supply sufficient power, the controller 130 can make the output amount of the engine generator 120 smaller than the lower limit of the limit range. Thereby, the controller 130 can suppress the consumption of fuel in the engine generator 120.

(Modification 3)
Next, Modification 3 will be described. The basic configuration and operation of this modification are the same as the configuration and operation of the distributed power supply system 100 shown in FIG. Therefore, the configuration and operation of the distributed power supply system 100 shown in FIG.

  In the above embodiment, the output amount of the engine generator 120 is basically larger than the output amount of the natural energy power supply device 110. However, the output amount of the natural energy power supply device 110 may be larger than the output amount of the engine generator 120.

  In this modification, the upper limit of the output allowable range of the natural energy power supply device 110 is 12 kW, and the lower limit is 0 kW. Therefore, the controller 130 maintains the output amount of the natural energy power supply device 110 within a range from 0 kW to 12 kW.

  FIG. 17 is a graph showing temporal changes in the output amounts of the natural energy power supply device and the engine generator in the present modification. FIG. 17 shows the same contents as FIG. 4, but in the example of FIG. 17, the output amount of the natural energy power supply device 110 varies within a range from 0 kW to 12 kW. That is, the controller 130 can greatly vary the output amount of the natural energy power supply device 110 compared to the example of FIG.

  FIG. 18 is a graph showing changes in power demand and power supply over time in this modification. Specifically, FIG. 18 shows temporal changes in the power demand amount of the load 200, the power supply amount of the natural energy power supply device 110, and the power supply amount of the engine generator 120, as in FIG.

  The power supply amount of the natural energy power supply device 110 shown in FIG. 18 corresponds to the output amount of the natural energy power supply device 110 shown in FIG. The power supply amount of the engine generator 120 shown in FIG. 18 corresponds to the output amount of the engine generator 120 shown in FIG.

  Also, the power demand amount of the load 200 shown in FIG. 18 corresponds to the sum of the power supply amount of the natural energy power supply device 110 and the power supply amount of the engine generator 120, as in the example of FIG. That is, the power demand amount of the load 200 corresponds to the total output amount of the output amount of the natural energy power supply device 110 and the output amount of the engine generator 120.

  Similarly to the example of FIG. 6, the controller 130 maintains the output amount (power supply amount) of the engine generator 120 within a predetermined limit range. In addition, the controller 130 maintains the output amount (power supply amount) of the natural energy power supply device 110 within the output allowable range of the natural energy power supply device 110. Then, the controller 130 adapts the total output amount of the output amount of the natural energy power supply device 110 and the output amount of the engine generator 120 to the power demand amount of the load 200.

  In this modification, the controller 130 maintains the output amount of the natural energy power supply device 110 within a range from 0 kW to 12 kW, and maintains the output amount of the engine generator 120 within a range from 6 kW to 8 kW. Then, the controller 130 adapts the total output amount of the output amount of the engine generator 120 and the output amount of the natural energy power supply device 110 to the power demand amount of the load 200 in the range from 6 kW to 20 kW.

  In other words, when the output amount (output allowable range) of the natural energy power supply device 110 is large, the controller 130 greatly varies the output amount of the natural energy power supply device 110, so that the power demand amount of the load 200 is largely varied. The overall output amount can be followed.

  In this modification, the output amount of the natural energy power supply device 110 may be reduced according to a predetermined condition as in Modification 1 or Modification 2. However, when the output of the natural energy power supply device 110 is stopped, even if the restriction on the output amount of the engine generator 120 is released, sufficient power is not supplied to the load 200 due to the allowable output range of the engine generator 120. there is a possibility.

  Therefore, the output amount of the natural energy power supply device 110 may be reduced based on the amount that the engine generator 120 can newly output power by releasing the restriction. Alternatively, an engine generator 120 having a large output allowable range may be used. For example, the engine generator 120 whose predetermined limit range with high power generation efficiency is a range from 6 kW to 8 kW and whose output allowable range is from 0 kW to 20 kW may be used. Thereby, sufficient electric power is supplied to the load 200.

  As described above, the distributed power supply system 100 according to the present invention has been described based on the embodiments (including modifications), but the present invention is not limited to the embodiments. Embodiments obtained by subjecting the embodiments to modifications conceived by those skilled in the art and other embodiments realized by arbitrarily combining a plurality of components in the embodiments are also included in the present invention.

  For example, another component may execute a process executed by a specific component. In addition, the order in which the processes are executed may be changed, or a plurality of processes may be executed in parallel.

  In addition, the present invention can be realized not only as a distributed power supply system 100 but also as a method including steps (processes) performed by each component constituting the distributed power supply system 100.

  For example, these steps may be executed by a computer (computer system) included in the distributed power supply system 100. The present invention can be realized as a program for causing a computer to execute the steps included in these methods. Furthermore, the present invention can be realized as a non-transitory computer-readable recording medium such as a CD-ROM on which the program is recorded.

  For example, when the present invention is realized by a program (software), each step is executed by executing the program using hardware resources such as a CPU, a memory, and an input / output circuit of a computer. . That is, each step is executed by the CPU obtaining data from a memory or an input / output circuit or the like, and outputting the calculation result to the memory or the input / output circuit or the like.

  In addition, a plurality of components included in the distributed power supply system 100 and the like may be realized as dedicated or general-purpose circuits, respectively. These components may be realized as a single circuit or may be realized as a plurality of circuits.

  A plurality of components included in the distributed power supply system 100 and the like may be realized as an LSI (Large Scale Integration) that is an integrated circuit (IC: Integrated Circuit). These components may be individually made into one chip, or may be made into one chip so as to include a part or all of them. The LSI may be referred to as a system LSI, a super LSI, or an ultra LSI depending on the degree of integration.

  The integrated circuit is not limited to an LSI, and may be realized by a dedicated circuit or a general-purpose processor. A programmable programmable gate array (FPGA) or a reconfigurable processor in which connection and setting of circuit cells inside the LSI can be reconfigured may be used.

  Furthermore, if integrated circuit technology that replaces LSI emerges as a result of advances in semiconductor technology or other derived technology, naturally, using that technology, a plurality of components included in the distributed power supply system 100 can be integrated. It may be broken.

  Finally, a plurality of modes such as the distributed power supply system 100 are shown as examples. These aspects may be appropriately combined. Moreover, the arbitrary structure etc. which were shown by said embodiment (a modification is included) may be added.

(First aspect)
A distributed power supply system 100 according to an aspect of the present invention includes a natural energy power supply device 110, an engine generator 120, and a controller 130, and supplies power to a load 200. The natural energy power supply device 110 includes a natural energy power generation device 111, a power supply circuit 112, a storage battery 113, and an inverter 114, and outputs the electric power converted by the inverter 114 to a power line to which the load 200 is connected.

  The natural energy power generation device 111 generates electric power using natural energy. The power supply circuit 112 generates power having a predetermined voltage from the power generated by the natural energy power generation device 111. The storage battery 113 is charged with electric power obtained from the power supply circuit 112, and the electric power charged in the storage battery 113 is discharged from the storage battery 113. Inverter 114 converts electric power obtained from power supply circuit 112 and storage battery 113 into AC electric power.

  The engine generator 120 generates electric power using an internal combustion engine. Further, the engine generator 120 outputs electric power generated using the internal combustion engine to a power line to which the load 200 is connected. The controller 130 controls the output amount of the natural energy power supply device 110 and the output amount of the engine generator 120 so that the output amount of the engine generator 120 is maintained within the limit range. Here, the limited range is a range that is predetermined as a range for making the power generation efficiency of the engine generator 120 higher than a predetermined power generation efficiency.

  Thereby, the distributed power supply system 100 can maintain the power generation efficiency of the engine generator 120 high. Furthermore, the distributed power supply system 100 can adjust both the output amount of the natural energy power supply device 110 and the output amount of the engine generator 120 with respect to the power demand amount of the load 200. Therefore, since the distributed power supply system 100 can supply the power output from the engine generator 120 to the load 200 without charging, the loss of the power output from the engine generator 120 can be suppressed.

(Second embodiment)
For example, the controller 130 outputs the natural energy power supply device 110 and the engine generator 120 so that the output amount of the engine generator 120 is maintained within the limit range only when the remaining capacity of the storage battery 113 satisfies a predetermined condition. The competence may be controlled.

  As a result, the distributed power supply system 100 reduces the output amount of the engine generator 120 only when it is assumed that the natural energy power supply device 110 can appropriately output power based on the remaining capacity of the storage battery 113. It can be kept within the limits. And when it is assumed that the natural energy power supply device 110 cannot output electric power appropriately, the distributed power supply system 100 can release the restriction on the output amount of the engine generator 120.

  Therefore, the distributed power supply system 100 can supply sufficient power to the load 200 even when the natural energy power supply device 110 is assumed to be unable to output power appropriately.

(Third aspect)
For example, the predetermined condition may be that the remaining capacity of the storage battery 113 is larger than the predetermined remaining capacity. Then, the controller 130 allows the natural energy power supply device 110 and the engine generator 120 to maintain the output amount of the engine generator 120 within the limit range only when the remaining capacity of the storage battery 113 is larger than the predetermined remaining capacity. May be controlled.

  Thereby, the distributed power supply system 100 maintains the power generation efficiency of the engine generator 120 high when it is assumed that the remaining capacity of the storage battery 113 is large and the natural energy power supply device 110 can appropriately output power. can do. The distributed power supply system 100 can supply sufficient power to the load 200 even when it is assumed that the remaining capacity of the storage battery 113 is small and the natural energy power supply device 110 cannot output power appropriately. it can.

(4th aspect)
For example, the controller 130 allows the natural energy power supply device 110 and the engine generator to maintain the output amount of the engine generator 120 within the limited range only when the power generation amount of the natural energy power generation device 111 satisfies a predetermined condition. The output amount of 120 may be controlled.

  As a result, the distributed power supply system 100 can be used only when the natural energy power supply device 110 is assumed to be able to output power appropriately based on the power generation amount of the natural energy power generation device 111. The output amount can be maintained within the limit range. And when it is assumed that the natural energy power supply device 110 cannot output electric power appropriately, the distributed power supply system 100 can release the restriction on the output amount of the engine generator 120.

  Therefore, the distributed power supply system 100 can supply sufficient power to the load 200 even when the natural energy power supply device 110 is assumed to be unable to output power appropriately.

(5th aspect)
For example, the predetermined condition may be that the power generation amount of the natural energy power generation apparatus 111 is larger than the predetermined power generation amount. Then, the controller 130 may control the output amount so that the output amount is maintained within the limit range only when the power generation amount of the natural energy power generation apparatus 111 is larger than the predetermined power generation amount. Specifically, only in this case, the controller 130 may control the output amounts of the natural energy power supply device 110 and the engine generator 120 so that the output amount of the engine generator 120 is maintained within the limit range. .

  Thereby, in the distributed power supply system 100, when it is assumed that the amount of power generated by the natural energy power generation apparatus 111 is large and the natural energy power supply apparatus 110 can appropriately output power, the power generation efficiency of the engine generator 120 is Can be kept high. The distributed power supply system 100 supplies sufficient power to the load 200 even when it is assumed that the amount of power generated by the natural energy power generation device 111 is small and the natural energy power supply device 110 cannot output power appropriately. can do.

(Sixth aspect)
For example, the natural energy power generation apparatus 111 may generate power using sunlight. And the controller 130 may estimate the electric power generation amount of the natural energy power generation apparatus 111 based on the amount of solar radiation or a date. Then, only when the predicted power generation amount is larger than the predetermined power generation amount, the controller 130 allows the natural energy power supply device 110 and the engine generator 120 to maintain the output amount of the engine generator 120 within the limit range. May be controlled.

  Thereby, the distributed power supply system 100 maintains the power generation efficiency of the engine generator 120 high when it is assumed that the natural energy power supply device 110 can appropriately output power based on the prediction of the power generation amount. can do. The distributed power supply system 100 can supply sufficient power to the load 200 even when it is assumed that the natural energy power supply device 110 cannot output power appropriately based on the prediction of the power generation amount. it can.

(Seventh aspect)
The control method according to an aspect of the present invention is a control method for the distributed power supply system 100 that supplies power to the load 200.

  The distributed power supply system 100 includes a natural energy power supply device 110 and an engine generator 120. The natural energy power supply device 110 includes a natural energy power generation device 111, a power supply circuit 112, a storage battery 113, and an inverter 114, and outputs the electric power converted by the inverter 114 to a power line to which the load 200 is connected.

  The natural energy power generation device 111 generates electric power using natural energy. The power supply circuit 112 generates power having a predetermined voltage from the power generated by the natural energy power generation device 111. The storage battery 113 is charged with electric power obtained from the power supply circuit 112, and the electric power charged in the storage battery 113 is discharged from the storage battery 113. Inverter 114 converts electric power obtained from power supply circuit 112 and storage battery 113 into AC electric power.

  The engine generator 120 generates electric power using an internal combustion engine. And the engine generator 120 outputs the electric power generated using the internal combustion engine to the power line to which the load 200 is connected.

  The control method of the distributed power supply system 100 is a control step of controlling the output amount of the natural energy power supply device 110 and the output amount of the engine generator 120 so that the output amount of the engine generator 120 is maintained within the limit range. (S131). The restriction range is a range that is predetermined as a range for making the power generation efficiency of the engine generator 120 higher than a predetermined power generation efficiency.

  Thereby, the power generation efficiency of the engine generator 120 is maintained high. Furthermore, it is possible to adjust both the output amount of the natural energy power supply device 110 and the output amount of the engine generator 120 with respect to the power demand amount of the load 200. Therefore, the electric power output from the engine generator 120 can be supplied to the load 200 without charging, and the loss of the electric power output from the engine generator 120 can be suppressed.

DESCRIPTION OF SYMBOLS 100 Distributed power supply system 110 Natural energy power supply device 111 Natural energy power generation device 112 Power supply circuit 113 Storage battery 114 Inverter 120 Engine generator 130 Controller 200 Load

Claims (7)

A distributed power supply system for supplying power to a load,
A natural energy power generation device that generates power using natural energy, a power supply circuit that generates power of a predetermined voltage from the power generated by the natural energy power generation device, and the power obtained from the power supply circuit are charged, A natural energy power supply device comprising: a storage battery from which charged power is discharged; and an inverter that converts the power obtained from the power supply circuit and the storage battery into AC power, wherein the power converted by the inverter is the load A natural energy power supply that outputs power to the connected power line,
An engine generator that generates electric power using an internal combustion engine and outputs the electric power generated using the internal combustion engine to the power line;
The output amount of the natural energy power supply device is maintained so that the output amount of the engine generator is maintained within a predetermined limit range as a range for making the power generation efficiency of the engine generator higher than a predetermined power generation efficiency. And a controller for controlling the output amount of the engine generator. The controller includes the output amount of the natural energy power supply device and the engine so that the output amount of the engine generator is maintained within the limit range only when the remaining capacity of the storage battery satisfies a predetermined condition. The distributed power supply system according to claim 1, wherein the output amount of the generator is controlled. The predetermined condition is that a remaining capacity of the storage battery is larger than a predetermined remaining capacity,
The controller includes an output amount of the natural energy power supply device so that an output amount of the engine generator is maintained within the limit range only when a remaining capacity of the storage battery is larger than the predetermined remaining capacity, and The distributed power supply system according to claim 2, wherein an output amount of the engine generator is controlled. The controller is configured to maintain the output amount of the natural energy power supply device so that the output amount of the engine generator is maintained within the limit range only when the power generation amount of the natural energy power generation device satisfies a predetermined condition. The distributed power supply system according to claim 1, wherein an output amount of the engine generator is controlled. The predetermined condition is that a power generation amount of the natural energy power generation device is larger than a predetermined power generation amount,
The controller controls the output of the natural energy power supply device so that the output amount of the engine generator is maintained within the limit range only when the power generation amount of the natural energy power generation device is larger than the predetermined power generation amount. The distributed power supply system according to claim 4, wherein the power amount and the output amount of the engine generator are controlled. The natural energy power generation device generates power using sunlight,
The controller is
Based on the amount of solar radiation or date, predict the amount of power generated by the natural energy generator,
Only when the predicted power generation amount is larger than the predetermined power generation amount, the output amount of the natural energy power supply device and the engine so that the output amount of the engine generator is maintained within the limit range. The distributed power supply system according to claim 5, wherein the output amount of the generator is controlled. A method for controlling a distributed power supply system for supplying power to a load, comprising:
The distributed power supply system includes:
A natural energy power generation device that generates power using natural energy, a power supply circuit that generates power of a predetermined voltage from the power generated by the natural energy power generation device, and the power obtained from the power supply circuit are charged, A natural energy power supply device comprising: a storage battery from which charged power is discharged; and an inverter that converts the power obtained from the power supply circuit and the storage battery into AC power, wherein the power converted by the inverter is the load A natural energy power supply that outputs power to the connected power line,
An engine generator that generates electric power using an internal combustion engine, and outputs the electric power generated using the internal combustion engine to the power line;
The control method of the distributed power supply system includes:
The output amount of the natural energy power supply device is maintained so that the output amount of the engine generator is maintained within a predetermined limit range as a range for making the power generation efficiency of the engine generator higher than a predetermined power generation efficiency. And a control method of the distributed power supply system including a control step of controlling an output amount of the engine generator.

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