JP2013062927A - Photovoltaic power generation system and power supply controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photovoltaic power generation system capable of combinedly achieving standby power reduction, effective use of surplus power and prevention of battery overcharging/overdischarging.SOLUTION: Usually, photovoltaic power generation power of a solar battery 1 is supplied to an AC load 5 through an inverter 4 and charged into a battery 3. The power supply controller 6, when an AC current value running through an AC load 5 is less than a current threshold value and a predetermined time elapses, stops the inverter 4 to reduce standby power and suppress overcharging of the battery 3. A battery charge monitoring circuit 16 always monitors a charging state of the battery 3 and surplus power after the battery 3 completes charging is supplied to a heater 18 through an output switching circuit 17 to store heat in hot water in a hot-water tank 19 and is supplied to a hot-water supply apparatus 20 and an air-conditioning apparatus 21. Otherwise, surplus power is stored in a cooling apparatus 22 as cold energy and supplied to a cold-temperature supply apparatus 23. Thus, effective use of surplus power can be achieved.

Description

  The present invention relates to a photovoltaic power generation system and a power supply control device.

  FIG. 6 is a block diagram showing a configuration of a general stand-alone photovoltaic power generation system. As shown in FIG. 6, in a general stand-alone photovoltaic power generation system, DC power generated by the solar battery 101 is charged to the battery 103 and supplied to the inverter 104 via the charging circuit 102. . This DC power is converted into AC power having a desired voltage by the inverter 104 and supplied to an AC load 105 such as a home appliance. Further, when the solar cell 101 is not generating power in rainy weather or at night, the DC power charged in the battery 103 is supplied to the inverter 104, converted into AC power by the inverter 104, and supplied to the AC load 105.

  Here, when the solar cell 101 is not generating power and the power supplied to the AC load 105 is zero, the battery 103 is disconnected and the power consumption of the inverter 104 is minimized so that the power consumption is wasted. Reduction. Further, during the daytime when the solar cell 101 generates power, the power (DC power) that has not been consumed by the AC load 105 is charged from the solar cell 101 to the battery 103 via the charging circuit 102, thereby generating power generated by the solar cell 101. Is recovered to the battery 103 without waste. Further, although not shown in FIG. 6, a first converter that boosts the power generation voltage of the solar cell and a second converter that boosts the voltage of the battery are connected in parallel to the inverter, so that the solar cell supplies the inverter. There is also disclosed a technique for preventing the conversion efficiency of the generated power of the solar cell from being lowered only once by converting the generated power voltage once (see, for example, Patent Document 1).

JP 2003-153464 A

  However, the independent photovoltaic power generation system disclosed in FIG. 6 and Patent Document 1 described above does not depend on the load state of the AC load 105 (that is, even if the AC load 105 is in an unloaded state). Is always working. For this reason, since the inverter 104 continuously consumes standby power, wasteful power consumption increases in the stand-alone photovoltaic power generation system, and the battery 103 may be overdischarged. In addition, since the electric power that is not consumed by the AC load 105 during the power generation of the solar battery 101 is continuously charged to the battery 103, the battery 103 may be overcharged and the life of the battery 103 may be reduced. . Further, the surplus power after the completion of charging of the battery 3 is not effectively used.

  That is, in the conventional stand-alone photovoltaic power generation system, reduction of standby power when the AC load 105 is unloaded, avoidance of life reduction of the battery 103 caused by overcharging during power generation of the solar battery 101, and power generation The surplus power usage method after the completion of charging from the solar cell 101 to the battery 103 is not considered at all. In other words, in the conventional technology, power resources in an independent solar power generation system that does not use commercial power from an electric power company are consumed wastefully, and the life of the battery is reduced. In the above conventional example, the stand-alone photovoltaic power generation system has been described. However, in a general photovoltaic power generation system including a grid-connected photovoltaic power generation system that is grid-connected to commercial power, standby power Reduction, effective use of surplus power, and avoidance of battery life reduction are not considered.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an easy-to-use solar power generation system.

  In order to achieve the above object, the present invention provides a photovoltaic power generation system in which photovoltaic power generated by a solar cell is supplied to an AC load via an inverter and charged to a battery. Current detection means for detecting an AC current value flowing from the AC load to the AC load, and controlling the start / stop of the inverter based on a comparison result between the AC current value detected by the current detection means and a current threshold, Provided is a solar power generation system including power control means for reducing power.

  As a preferred mode, the power supply control means automatically stops the inverter to reduce the standby power when the alternating current value is less than the current threshold value and a predetermined time has elapsed. Further, the power supply control means periodically operates the inverter intermittently while reducing the standby power, and automatically starts the inverter when the AC current value becomes equal to or greater than the current threshold value.

  Further, according to the present invention, an easy-to-use solar power generation system can be provided.

  According to the present invention, when the AC load is not used, it is possible to prevent overdischarge of the battery by reducing the standby power of the entire photovoltaic power generation system including the inverter. Further, by storing the surplus power after the charging of the battery is completed as heat or cold, it is possible to realize both the extension of the battery life by preventing overcharge and the effective use of the surplus power.

It is a block diagram which shows the structure of the stand-alone photovoltaic power generation system applied to 1st Embodiment of this invention. In the stand-alone photovoltaic power generation system shown in FIG. 1, it is the time chart which showed the operation state of each part until an inverter stops automatically. In the stand-alone photovoltaic power generation system shown in FIG. 1, it is the time chart which showed the operation state of each part until an inverter starts automatically. 2 is a flowchart showing a flow of operation of a power supply control device for reducing standby power of an inverter in the stand-alone photovoltaic power generation system shown in FIG. 1. In the stand-alone photovoltaic power generation system shown in FIG. 1, it is the time chart which showed the operation state of each part until it heat-stores with surplus electric power. It is a block which shows the structure of a general independent type solar power generation system.

"Overview"
In the embodiment of the present invention, an independent solar power generation system that completes a power system system of a solar cell by an independent power system without performing grid connection with commercial power will be described as a solar power generation system. That is, in the stand-alone photovoltaic power generation system according to the embodiment of the present invention, referring to FIG. 1, basically, the photovoltaic power generation generated by the solar cell 1 is similar to the conventional stand-alone photovoltaic power generation system. The electric power is supplied to the AC load 5 as AC power via the inverter 4, and the power that is not used by the AC load 5 (that is, the difference power between the photovoltaic power and AC power) is used as battery charging power. The battery 3 is configured to be charged.

  In the stand-alone photovoltaic power generation system of this embodiment, in addition to such a basic configuration, as shown in FIG. 1, when the AC load 5 is stopped, the inverter 4 is automatically stopped and the AC load 5 is restarted. An automatic stop / automatic start function for automatically starting the inverter 4 is added at the time of startup. Thus, when the AC load 5 is stopped, the inverter 4 is stopped to reduce standby power, thereby preventing unnecessary overdischarge of the battery 3.

  Further, surplus power that is not consumed by the AC load 5 and not stored by the completion of charging of the battery 3 is supplied to the hot water tank 19 as hot water by supplying power to the heater 18. A hot water supply function for storing heat and supplying hot water from the hot water supply device 20 and the cooling / heating device 21 is added. Further, a cooling / heating supply function for supplying the above-described surplus power to the cooling device 22 to store the cooling energy and supplying the cooling energy from the cooling / heating supply device 23 is added. With these functions, it is possible to prevent the battery 3 from being overcharged by surplus power and to effectively use surplus power.

  That is, the stand-alone photovoltaic power generation system according to the present embodiment effectively uses the inverter's automatic stop / automatic start function for reducing standby power and surplus power, compared to the conventional stand-alone photovoltaic power generation system. By adding the hot water supply function and the cold heat supply function for the purpose, reduction of standby power, effective use of surplus power, and prevention of battery overcharge / overdischarge can be realized in combination.

  Hereinafter, an embodiment of a stand-alone photovoltaic power generation system according to the present invention will be described in detail with reference to the drawings.

<< First Embodiment >>
<Configuration of stand-alone photovoltaic power generation system>
First, the configuration of the stand-alone photovoltaic power generation system according to the first embodiment of the present invention will be described. FIG. 1 is a block diagram showing a configuration of an independent photovoltaic power generation system applied to the first embodiment of the present invention. In other words, FIG. 1 shows a stand-alone photovoltaic power generation system according to the first embodiment of the present invention. Reduction of standby power of the entire system including the inverter 4, effective use as a heat source by storing surplus power, and battery 3 shows a configuration of a combined stand-alone photovoltaic power generation system that is configured to realize a combination of 3 overcharge / overdischarge prevention and the like.

  As shown in FIG. 1, the stand-alone photovoltaic power generation system applied to the first embodiment of the present invention is connected from the solar cell 1 to the output switching circuit 17 via the charging circuit 2. The first output terminal of the output switching circuit 17 is connected to the inverter 4 and is connected to the battery 3 via the battery charge monitoring circuit (battery charge monitoring means) 16. The output side of the inverter 4 is connected to an AC load 5 via a CT (current detection means) 7. Furthermore, the first output terminal of the output switching circuit 17 is connected to a power control device (power control means) 6 that controls the entire stand-alone photovoltaic power generation system.

  Further, the second output terminal of the output switching circuit 17 is connected to a heater (heating means) 18 and a cooling device (cooling means) 22 in the hot water tank 19. Furthermore, a hot water supply device 20 and a cooling / heating device 21 are connected from the hot water tank 19, and a cooling / heating supply device 23 is connected from the cooling device 22. The output switching circuit 17 is connected to a charge / heat storage mode manual switch 24 that can manually switch between the charge mode and the heat storage mode.

  Further, CT 7, inverter operation contact 8, manual return contact (manual return means) 9, and external return contact (external return means) 10 are connected from the power supply control device 6. The power supply control device 6 receives the current monitoring value of the AC current value flowing to the AC load 5 detected by the CT 7, the signal of the manual return contact 9, and the signal of the external return contact 10 to operate the inverter operation contact 8. The inverter 4 has a function for starting / stopping.

  The current monitoring control circuit 11 in the power supply control device 6 counts the current monitoring function for monitoring the AC current value flowing to the AC load 5 and the energization time of the AC current flowing from the inverter 4 to the AC load 5 via CT7. A timer function is provided, and a signal indicating the operation state of the AC load 5 is transmitted to the continuous operation command circuit 12. The power supply of the power supply control device 6 is supplied from the battery 3.

  Further, the current monitoring control circuit 11 provided in the power supply control device 6 has a function of outputting an activation signal to the periodic operation command circuit (periodic operation command means) 13 to cause the inverter 4 to intermittently operate. The periodic operation command circuit 13 is supplied with power from the periodic operation command circuit power supply 15. The two diodes 14 in the figure have a function of preventing the signals amplified by the continuous operation command circuit 12 and the periodic operation command circuit 13 from flowing into the other amplifier circuit, and the continuous operation command circuit 12 and the periodic operation command circuit 13 are provided to maintain the independence of the operations.

  That is, in the independent solar power generation system of this embodiment, in addition to the conventional independent solar power generation system, the current monitoring control circuit 11 of the power supply control device 6 has an AC current value ( (Current monitoring value) is monitored by CT7, and when the alternating current value is less than the current threshold value and a predetermined time has elapsed, the inverter 4 is automatically stopped to reduce standby power.

  Further, in order for the continuous operation command circuit 12 of the power supply control device 6 to automatically restart the inverter 4, the inverter 4 is periodically intermittently operated, and the AC current value flowing through the AC load 5 at that time is the current threshold value. In the case described above, the inverter 4 is automatically switched to the continuous operation.

  In addition, in order to be able to use the AC load 5 arbitrarily, the inverter 4 is provided with a manual return contact 9, and the manual return contact 9 is manually operated to start the inverter 4 arbitrarily, and the external return The contact 10 is configured to have a function of automatically starting the inverter 4 in conjunction with a start switch (not shown) of the AC load 5. Here, the external return contact 10 is provided on the AC load 5 side. When the signal from the external return contact 10 is received by the continuous operation command circuit 12 of the power supply control device 6, the inverter operation contact 8 is operated. Thus, the inverter 4 can be automatically started.

  That is, the stand-alone photovoltaic power generation system according to the present embodiment includes power that is not used as AC power by the AC load 5 among the photovoltaic power generated by the solar cell 1 (that is, solar power and AC power). In addition to the basic configuration of charging the battery 3 as the battery charging power, a battery charge monitoring circuit 16, an output switching circuit 17, a heater 18, a hot water tank 19, and a cooling device 22 are provided. Have been added. As a result, surplus power after completion of charging of the battery 3 is supplied to the heater 18 to heat the water in the hot water tank 19 to be stored as hot water, and can be used as a hot heat source for the hot water supply equipment 20 and the air conditioning equipment 21. It is configured as follows. The surplus power is supplied to the cooling device 22 so that it can be stored as cold heat such as cold water or ice and supplied to the cold temperature supply device 23 as a cold heat source.

<Operation of independent solar power generation system>
Next, the operation of the stand-alone photovoltaic power generation system according to this embodiment shown in FIG. 1 will be described. FIG. 2 is a time chart showing the operating state of each part until the inverter automatically stops in the stand-alone photovoltaic power generation system shown in FIG. That is, in FIG. 2, the horizontal axis is the time axis, and the vertical axis indicates the waveform of the inverter 4 in the operating / stopped state, the AC load 5 in the operating / stopped state, the approximate waveform of the alternating current value at each time, and the current threshold from the top. It shows. Therefore, with reference to the time chart of FIG. 2, the operation | movement outline | summary for the standby power reduction of the inverter 4 in the stand-alone photovoltaic power generation system shown in FIG. 1 is demonstrated.

  As shown in FIG. 2, in the operation / stop state of the inverter 4 and the AC load 5 after the time t0, the AC load 5 is stopped during the period from the time t1 to the time t2 and during the period from the time t3 to the time t4. The alternating current value is smaller than the current threshold. However, since each period (t1 to t2, t3 to t4) is shorter than a predetermined time set in advance, the inverter 4 continues to operate. However, in the period from time t5 to t6, the AC load 5 stops, the AC current value becomes smaller than the current threshold value, and the time during which the AC current value is smaller than the current threshold value is longer than the predetermined time. The inverter 4 stops.

  That is, during the continuous operation of the AC load 5 (time t0 to t1), when the AC current value (current monitoring value) monitored by CT7 is equal to or greater than the current threshold, the inverter 4 is continuously operated. Further, during the intermittent operation of the AC load 5 (time t1 to t4), even if the AC current value monitored by CT7 is less than the current threshold, the AC load 5 is stopped (time t1 to t2 and time). When t3 to t4) are equal to or shorter than a predetermined time (in FIG. 2, one scale and two scales on the time axis), the inverter 4 is continuously operated as it is.

  However, when the AC load 5 stops at time t5, the AC current value monitored by CT7 becomes less than the current threshold value, and a predetermined time or more (time of 3 scales from time t5 to t6) has elapsed, time t6 Then, the inverter 4 is stopped. Thereby, the standby power of the inverter 4 can be reduced after the time t6. Here, the current threshold value to be compared with the AC current value of the AC load 5 monitored by the CT 7 is set to a value that exceeds the standby current of the AC load 5, so that the stable use of the stand-alone photovoltaic power generation system can be achieved. Sex can be secured.

  Next, the standby power amount that can be reduced by the stand-alone photovoltaic power generation system of the present invention will be described. For example, when the rated output power of the inverter 4 is 500 W and the power conversion efficiency is 90%, the standby power amount that can be reduced when it is assumed that about 50% of the power conversion loss is standby power will be described.

  The standby power of the inverter 4 is (500 W × (1-0.9)) / 2 = 25 W. Therefore, when 10 hours have passed since the AC load 5 is stopped, the standby power amount of 25 W × 10 h = 250 Wh can be reduced. Here, when the independent solar power generation system uses the battery 3 of 12V, the electric energy of the battery 3 of (25W / 12V) × 10h = 21 Ah can be reduced.

  Next, a method of automatically starting the inverter 4 according to the load state of the AC load 5 while maintaining the reduced state of the standby power of the inverter 4 with respect to the inverter 4 stopped to reduce the standby power Will be described with reference to FIG. FIG. 3 is a time chart showing an operation state of each part until the inverter 4 is automatically activated in the stand-alone photovoltaic power generation system shown in FIG.

  That is, in FIG. 3, the horizontal axis is the time axis, and the vertical axis indicates from the upper stage, the operation / stop state of the inverter 4, the operation / stop state of the AC load 5, and the approximate waveform and current threshold value of the AC current value at each time. It shows. In this figure, the periodic operation command circuit 13 of the power supply control device 6 causes the inverter 4 to be intermittently operated periodically, and the current (AC current value) flowing through the AC load 5 at that time is monitored by the current monitoring control circuit 11. It shows that the operation / stop state of the AC load 5 is detected and the operation / stop state of the inverter 4 is switched. In other words, the current monitoring control circuit 11 provided in the power supply control device 6 outputs a start signal to the periodic operation command circuit 13 to cause the inverter 4 to operate intermittently.

  As shown in FIG. 3, the inverter 4 is intermittently operated intermittently, and the alternating current value of the alternating current load 5 is as shown in the periods t1 to t2, t3 to t4, t5 to t6, and t7 to t8. If it is less than the current threshold, the inverter 4 is set to the periodic operation mode (that is, the standby power reduction state due to the pseudo stop state). Then, when the AC load 5 starts operation at time t9 and the AC current value flowing to the AC load 5 becomes equal to or greater than the current threshold value at time t10, the inverter 4 is turned on by the continuous operation command circuit 12 of the power supply control device 6. Let it run continuously. In addition, the broken line from the time t9 to t10 in the figure shows the period from the start of operation of the AC load 5 until the inverter 4 is automatically started.

  With the above operation, after time t10 when the inverter 4 starts continuous operation, the periodic operation command circuit power source 15 shown in FIG. Stop operation. Thereby, the power consumption of the power supply control device 6 during the continuous operation of the AC load 5 can be reduced, and the standby power can be reduced.

  Further, in addition to the function of automatically starting the inverter 4 as described above, a manual return contact 9 can be provided as shown in FIG. That is, the manual return contact 9 can realize a function of manually setting the inverter 4 to a continuous operation state. In addition, an external return contact 10 is provided on the AC load 5, and a function for automatically starting the inverter 4 is realized by connecting the start contact of the AC load 5 to the external return contact 10 and interlocking with the external return contact 10. It can also be made. In addition, by directly inputting the signals of the manual return contact 9 and the external return contact 10 to the continuous operation command circuit 12 of the power supply control device 6, the inverter 4 can be reliably operated at an arbitrary timing.

  FIG. 4 is a flowchart showing an operation flow of the power supply control device for reducing the standby power of the inverter in the stand-alone photovoltaic power generation system shown in FIG. Therefore, an operation flow for reducing the standby power of the inverter 4 will be described with reference to FIG. First, when the inverter 4 is in continuous operation (step S1), the power supply control device 6 determines whether or not the AC current value flowing to the AC load 5 is less than the current threshold and a predetermined time has elapsed ( Step S2).

  Here, when the alternating current value is not less than the current threshold value, or when the predetermined time has not elapsed even though the alternating current value is less than the current threshold value (No in step S2), the determination in step S2 is continued. On the other hand, in step S2, when the AC current value flowing to the AC load 5 is less than the current threshold and a predetermined time has elapsed (Yes in step S2), the power supply control device 6 automatically stops the inverter 4 (step S3). . Thereby, the standby power of the inverter 4 can be reduced.

  Thereafter, the power supply control device 6 starts a periodic operation mode in which the inverter 4 is intermittently operated intermittently (step S4). Then, the power supply control device 6 determines whether or not the manual return contact 9 of the inverter 4 is turned on (step S5). If the manual return contact 9 is not turned on (No in step S5). ), It is determined whether or not the external return contact 10 of the inverter 4 is turned on (step S6).

  Here, if the external return contact 10 of the inverter 4 is not ON (No in step S6), the power supply control device 6 continues the periodic operation of the inverter 4 (step S7), and the alternating current flowing to the alternating load 5 It is determined whether or not the value is greater than or equal to the current threshold (step S8). At this time, if the alternating current value is not equal to or greater than the current threshold value (No in step S8), the process returns to step S5 and repeats the processes of steps S5 to S8 described above. The power supply control device 6 resumes the continuous operation of the inverter 4 (Yes in S8) (step S9).

  When the manual return contact 9 is ON in step S5 (Yes in step S5) or when the external return contact 10 of the inverter 4 is ON in step S6 (Yes in step S6), The power supply control device 6 immediately restarts the continuous operation of the inverter 4 (step S9).

  FIG. 5 is a time chart showing an operation state of each part until heat is stored by surplus power in the stand-alone photovoltaic power generation system shown in FIG. That is, in FIG. 5, the horizontal axis is the time axis, and the vertical axis is, from the top, the solar power generated by the solar cell 1, the AC power output from the inverter 4 to the AC load 5, and the solar cell 1 to battery 3 shows the battery charging power charged to 3 and the heat storage power supplied to the heater 18 and the cooling device 22 as surplus power.

  Therefore, the mechanism of heat conversion and heat storage using surplus power will be described with reference to FIG. As shown in FIG. 5, after the solar cell 1 starts generating power at time t <b> 1 and solar power generation power is generated, the solar power generation power is charged to the battery 3 as battery charging power. Then, during the period until the AC load 5 starts at time t2 and stops at time t3, the difference power obtained by subtracting the AC power consumed by the AC load 5 from the photovoltaic power generated by the solar cell 1 is charged by the battery. The battery 3 is charged with electric power.

  Further, during the period from time t3 to time t4, the AC load 5 is stopped and the AC power becomes zero, so that all the photovoltaic power generated by the solar cell 1 is charged to the battery 3 as battery charging power. Is done.

  Here, the battery charge monitoring circuit 16 shown in FIG. 1 detects the charging state of the battery 3 in real time by constantly monitoring the charging voltage and charging current of the battery 3. Therefore, after the battery charge monitoring circuit 16 detects the completion of charging of the battery 3 at time t4, the power supply control device 6 switches the path of the output switching circuit 17 from the output switching circuit 17 using the solar power generation power as surplus power. Power is supplied to the heater 18 or the cooling device 22.

  That is, after the time t4 when the charging from the solar cell 1 to the battery 3 is completed and surplus power is generated, the solar power generation power is all surplus power during the period until the time t5 when the power generation of the solar cell 1 is stopped. This surplus power is supplied to the heater 18 or the cooling device 22 as heat storage power. Thereby, warm water is stored in the warm water tank 19 by heating of the heater 18, and cold heat is stored in the cooling device 22 as cold water or ice.

  To summarize the above, FIG. 5 shows the photovoltaic power generated by the solar cell 1, the AC power supplied to the AC load 5, the battery charging power charged to the battery 3, the heater 18 and the cooling device 22. The solar power generated by the solar cell 1 is charged to the battery 3 as battery charging power when the AC load 5 is stopped. (Time t1 to t2). Next, when the AC load 5 is activated at time t2, a part of the photovoltaic power is consumed by the AC load 5 as AC power, and the difference power between the photovoltaic power and the AC power is used as the battery charging power. (Time t2 to t3).

  After that, when the AC load 5 is stopped again and the AC power becomes zero at time t3, all the photovoltaic power is converted into battery charging power and charged to the battery 3 (time t3 to t4).

  After the battery charge monitoring 16 detects the completion of charging of the battery 3 based on the charging voltage and charging current of the battery 3 (after time t4), all the photovoltaic power generation becomes surplus power, and the output switching circuit 17 is Then, power is supplied as heat storage power to the heater 18 or the cooling device 22. Further, the heater 18 heats the water in the hot water tank 19 to be used as a heat source, and the cooling device 22 stores and uses the cold heat source as cold water or ice (time t4 to t5).

  Here, since the charging of the battery 3 is completed after the time t4, the power supply control device 6 performs the battery charging monitoring circuit 16 that monitors the charging state of the battery 3 after the time t4 when the charging of the battery is completed. The power supply may be shut off. As a result, the power consumed by the battery charge monitoring circuit 16 can be reduced, so that the standby power of the entire photovoltaic power generation system can be reduced.

  FIG. 5 shows a state in which the surplus power after the completion of charging of the battery 3 is detected at time t4 as the heat storage power after the AC load 5 is stopped at time t3. Therefore, after time t4, all of the photovoltaic power generation power becomes surplus power and is used as heat storage power.

  However, when the AC load 5 is operating until the time after the time t4 and the AC power is supplied to the AC load 5 until the time after the time t4, the photovoltaic power generation power is generated after the time t4. The power obtained by subtracting the AC power from the power becomes surplus power and is used as the heat storage power.

  Further, when the AC load 5 is restarted, power supply from the battery 3 to the AC load 5 is started. When the battery charge monitoring circuit 16 detects a decrease in the charge capacity of the battery 3, the photovoltaic power generated by the solar cell 1 is again sent to the inverter 4 and the battery 3 by switching the output switching circuit 17. Can be supplied automatically.

  The charge / heat storage mode manual changeover switch 24 shown in FIG. 1 is a switch that enables selection of priority switching between the charge mode for the battery 3 and the heat storage mode for the heater 18 and the cooling device 22. Therefore, by operating the charge / heat storage mode manual changeover switch 24, the battery 3 can be charged manually by switching to the charge mode manually, or the heater 18 and the cooling device 22 can be fed by switching to the heat storage mode. It becomes possible to do.

  As described above, surplus power is supplied to the heater 18 as heat storage power, and the hot water stored in the hot water tank 19 is used as a heat source by the hot water supply device 20 and the cooling / heating device 21. Further, by supplying surplus power as heat storage power to the cooling device 22, cold water or ice stored in the cooling device 22 is used as a cold heat source by the cold temperature supply device 23. In this way, the surplus power of the photovoltaic power can be effectively used as a heat source regardless of day or night. In particular, in an independent solar power generation system in which power resources are scarce compared to a grid-connected solar power generation system, the use of such surplus power significantly increases the effect of effectively using natural resources.

  That is, the stand-alone photovoltaic power generation system according to the present embodiment has a battery 3 that reduces standby power, improves usability, and optimally distributes surplus power as compared to a general stand-alone photovoltaic power generation system. It is possible to prevent overcharge / overdischarge and to extend the service life. As a result, it is possible to extend the life and improve the reliability of the entire stand-alone photovoltaic power generation system.

  Moreover, as one of the effective uses of surplus power, the surplus power is converted into thermal energy, whereby heat is stored in the hot water tank 19 as heat, and heat is stored in the cooling device 22 as cold energy. By supplying the hot water supply device 20, the cooling / heating device 21, and the cooling / heating device 23, the surplus power of the photovoltaic power can be used as a heat source regardless of day or night.

  As described above, according to the stand-alone photovoltaic power generation system of the present embodiment, the standby power of the inverter 4, the periodic operation command circuit 13, the battery charge monitoring circuit 16, and the like is reduced, so Can be prevented. Further, by supplying surplus power to the heater 18 and the cooling device 22, it is possible to prevent the battery 3 from being overcharged, and to prevent the life of the battery 3 from being reduced, thereby extending the life of the stand-alone photovoltaic power generation system. Can be planned. Furthermore, surplus power generated by the completion of charging of the battery 3 without being consumed by the AC load 5 among the photovoltaic power generated by the solar cell 1 is supplied to the heater 18 to store it as hot heat, or the cooling device 22 It can be used by supplying power to and storing it as cold energy. Thereby, the surplus power can be effectively used as a heat source for the hot water supply device 20 and the air conditioning device 21 and can be effectively used as a cold heat source by the cold temperature supply device 23.

<< Second Embodiment >>
In the second embodiment of the present invention, an application example of a method of using surplus power generated secondarily by a solar power generation system or a wind power generation system will be described. In other words, not only the stand-alone solar power generation system and the grid-connected solar power generation system, but the surplus power generated by the natural energy power generation system such as solar power generation and wind power generation is stored as hot or cold heat and stored. Thermal energy can be used in various fields as hot water supply equipment, air conditioning equipment, and industrial heat sources.

Incidentally, in the photovoltaic power generation system of FIG. 1, the heater 18 is described as an image of an electric heater. However, instead of an electric heater, a first refrigeration cycle such as a so-called Ecocute (registered trademark) system having a heat pump function is used. The method for using surplus power described in the embodiment can be applied. In other words, a system that recovers surplus power as heat energy at a relatively low cost by supplying surplus power extracted by the technique described in the first embodiment to a compressor of a refrigeration cycle such as an eco-cute system is constructed. can do.
Note that the refrigeration cycle can be used for both a hot water heater and a chiller by using a condenser and an evaporator (not shown), and can also be used for an air conditioner for air conditioning.

<Summary>
As described above, the solar power generation system according to the present invention has been specifically described by taking the embodiment of the stand-alone solar power generation system as an example, but the present invention is not limited to the contents of the above-described embodiment, Needless to say, various modifications can be made without departing from the scope of the invention. That is, the present invention is not limited to a stand-alone photovoltaic power generation system, but also in a grid-connected photovoltaic power generation system that is linked to a commercial power grid, reduction of standby power, effective use of surplus power, and battery overcharging. / It can be applied to overdischarge prevention. Further, the present invention can be similarly applied to a natural energy power generation system including a wind power generation system and a tidal power generation system as well as the independent / interconnection type solar power generation system.

  In particular, the present invention can be effectively used as a stand-alone photovoltaic power generation system installed on the sea, a remote island, a mountain hut or the like where commercial power cannot be received. Even in the grid-connected solar power generation system, the standby power can be effectively reduced, the surplus power can be effectively used, and the battery can be overcharged / overdischarged. Moreover, it can utilize not only in a solar power generation system but in a natural energy power generation system including a wind power generation system and a tidal power generation system.

DESCRIPTION OF SYMBOLS 1 Solar cell 2 Charging circuit 3 Battery 4 Inverter 5 AC load 6 Power supply control apparatus (power supply control means)
7 CT (current detection means)
8 Inverter operation contact 9 Manual return contact (manual return means)
10 External return contact (external return means)
11 current monitoring control circuit 12 continuous operation command circuit 13 periodic operation command circuit (periodic operation command means)
14 Diode 15 Periodic operation command circuit power supply 16 Battery charge monitoring circuit (battery charge monitoring means)
17 Output switching circuit 18 Heater (heating means)
19 Hot water tank 20 Hot water supply equipment 21 Air conditioning equipment 22 Cooling device (cooling means)
23 Cooling / Cooling Equipment 24 Charging / Heat Storage Mode Manual Switch

Claims (14)

A photovoltaic power generation system in which photovoltaic power generated by a solar cell is supplied to an AC load via an inverter and charged to a battery,
Current detection means for detecting an AC current value flowing from the inverter to the AC load;
A photovoltaic power generation system comprising: power supply control means for controlling start / stop of the inverter based on a comparison result between an alternating current value detected by the current detection means and a current threshold value, and reducing standby power .   2. The power supply control unit according to claim 1, wherein when the AC current value is less than the current threshold and a predetermined time has elapsed, the inverter is stopped to reduce the standby power. Solar power system.   3. The power supply control unit according to claim 2, wherein the power supply control unit periodically and intermittently operates the inverter while the standby power is reduced, and starts the inverter when the AC current value is equal to or greater than the current threshold value. The described solar power generation system.   The said power supply control means reduces the said stand-by power by interrupting | blocking the power supply of the periodic operation command means which makes this inverter operate | move intermittently after starting the said inverter. Solar power system.   The power supply control means reduces the standby power by cutting off the power supply of the battery charge monitoring means for monitoring the state of charge of the battery after the charging of the battery is completed. 4. The solar power generation system according to any one of 4.   The photovoltaic power generation system according to any one of claims 1 to 5, further comprising manual return means for manually starting the inverter during the reduction of the standby power.   The solar power generation system according to any one of claims 1 to 6, further comprising external return means for starting up the inverter during the reduction of the standby power.   6. The surplus power of the photovoltaic power generation is supplied to a heating unit and stored in a hot water tank when the charging state of the battery monitored by the battery charge monitoring unit is complete. The solar power generation system in any one of thru | or 7.   The solar energy power generation system according to claim 8, wherein the thermal energy stored in the hot water tank is supplied to at least one of a hot water supply device and an air conditioning device.   The surplus power of the photovoltaic power generation is fed to a cooling means and stored as cold heat when the charging state of the battery monitored by the battery charge monitoring means is complete. The solar power generation system in any one of.   The solar energy power generation system according to claim 10, wherein the heat energy stored by the cooling unit as cold heat is supplied to a cold temperature supply device.   The solar power according to claim 8, wherein the surplus power fed to the heating unit or the cooling unit can be switched to a feeding system to the AC load and the battery at an arbitrary timing. Photovoltaic system.   13. The solar power generation system according to claim 1, wherein the solar battery power system is configured as an independent solar power generation system completed by an independent power system. Solar power generated by a solar battery is a power supply control device in a solar power generation system that is supplied to an AC load via an inverter and charged to a battery,
An AC current value flowing from the inverter to the AC load is detected;
A power supply control device that controls start / stop of the inverter based on a comparison result between the detected AC current value and a current threshold value, and reduces standby power.

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