JP2001069688A - Independent photovoltaic power generation system and power generation method - Google Patents

Abstract

(57) [Problem] An object of the present invention is to charge a storage battery safely and efficiently with a desired current and voltage without using a large-capacity solar cell, and to reduce the size and cost of a charger. An object of the present invention is to provide a stand-alone photovoltaic power generation system and a power generation method that can realize price reduction. The present invention relates to a solar cell that generates electric power by sunlight, a converter connected to an output of the solar cell, an electric double layer capacitor connected to an output of the converter, and a converter. Chargers 6-1 to 6-p to 6-n connected to the output of
And a plurality of Ni-MH storage batteries 7-1 to 7-q to 7 connected to chargers 6-1 to 6-p to 6-n, respectively.
-N and a plurality of Ni-MH storage batteries 7-1 to 7-q to 7-
and a load 5 connected to the n output.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stand-alone photovoltaic power generation system for supplying electric power generated by a photovoltaic power generator to a load or a power converter, and a power generation method.

[0002]

2. Description of the Related Art FIG. 2 shows a block diagram of a conventional stand-alone photovoltaic power generation system. 11 is a solar power generator, 15
-1, 15-2 and 15-3 are reverse current blocking diodes, 12
Is a load or power converter, 14 is a power storage device, 13
Is a charger.

The power generated by the photovoltaic power generator 11 is supplied to a power storage device 14 via a backflow prevention diode 15-1 and a charger 13, and is also supplied to a load or power converter via a backflow prevention diode 15-2. It is supplied to the device 12. When the power generated by the photovoltaic power generation device 11 is lower than the load or the power consumption of the power conversion device 12, the shortage power is supplied from the power storage device 14 via the backflow prevention diode 15-3 to the load or the power conversion device 12. To supply.

[0004] By using the above configuration, even when the power generated by the photovoltaic power generator 11 falls below the power consumption of the load or the power converter 12 due to nighttime, irregular weather, or the like, the load or the power converter 12 is supplied to the load or power converter 12. Power can be supplied from the power storage device 14, and a highly reliable independent solar power generation system can be constructed.

[0005]

SUMMARY OF THE INVENTION In a stand-alone photovoltaic power generation system, in order to supply a stable power to a load or a power converter even in the case of nighttime or long-term irregular weather,
A large-capacity backup power storage device is required. Since the rated capacity of the power storage device is designed to be larger than the rated capacity of the photovoltaic power generator, for example, the number of days of continuous insolation compensation is set to 1
When the system is designed in about 0 days, the amount of charge per hour for the power storage device is about 3% (0.03C) of the capacity of the power storage device, and the current value is a low rate even during the daytime when the weather is fine. . When a storage battery, particularly a nickel-metal hydride storage battery or a lithium ion storage battery, is used as the power storage device, charging efficiency at such a low rate of charging is greatly reduced, and the power storage device may not be fully charged. However, there arises a problem that desired reliability cannot be exhibited.

In order to solve this problem, a method of increasing the charging power by setting the capacity of the photovoltaic power generation device to a large value can be considered. A switching element, a reactor, which constitutes a charger due to an increase in current flowing through the charger,
A problem arises in that the size of the capacitor and the like must be increased and the price of the charger must be increased accordingly.

Further, the power generated by the photovoltaic power generator fluctuates with the amount of solar radiation, and it is difficult to always charge the power storage device with a stable current and voltage using only the power generated from the photovoltaic power generator. When charging is performed using such unstable current and voltage, the voltage and temperature of the power storage device fluctuate irregularly, and it is difficult to detect full charge when a storage battery is used as the power storage device. As a result, deterioration and destruction of the power storage device due to overcharging, and a reduction in system reliability due to insufficient charging of the power storage device are inevitable.

[0008] The present invention has been made in view of the above circumstances, and a solar power generation apparatus in which the generated power is not constant, such as a solar cell having a large capacity by temporarily storing the generated power of the solar cell in an electric double layer capacitor. Without using it, it is possible to charge storage batteries safely and efficiently with desired current and voltage, reduce the power flowing through multiple chargers, and realize smaller and less expensive chargers. It is an object to provide a solar photovoltaic power generation system and a power generation method.

[0009]

In order to achieve the above object, a stand-alone photovoltaic power generation system according to the present invention is connected to a photovoltaic power generator for generating electric power by sunlight and an output of the photovoltaic power generator. A power conversion device, a power storage device connected to the output of the power conversion device, a plurality of chargers connected to the output of the power conversion device and the power storage device, respectively corresponding to the charger. It is characterized by comprising a plurality of storage batteries connected, and a load connected to outputs of the plurality of storage batteries.

Further, the present invention is the above-mentioned independent type solar power generation system, wherein a load is connected to outputs of a plurality of storage batteries via switches.

The present invention also relates to the above-mentioned stand-alone photovoltaic power generation system, wherein a load is connected to outputs of a plurality of storage batteries via a backflow prevention diode.

The present invention also relates to the above-mentioned stand-alone type photovoltaic power generation system, wherein the power conversion device has a maximum power follow-up control function for causing the photovoltaic power generation device to perform a power generation operation under the condition that the photovoltaic power generation device converts the sunlight into power most efficiently. It is characterized by doing.

Further, the present invention is the above-mentioned stand-alone type photovoltaic power generation system, wherein the power converter has means for preventing overcharging of the power storage device when the power storage device is fully charged. It is characterized by the following.

Further, the present invention is the above-mentioned stand-alone type photovoltaic power generation system, wherein an arbitrary number of storage batteries are selected from a plurality of storage batteries, and a charger having an output connected to the arbitrary number of storage batteries is operated. And means for charging the battery.

Further, the present invention is the above-mentioned stand-alone photovoltaic power generation system, wherein charging of an arbitrary number of storage batteries is performed by changing the number of storage batteries to be selected according to the amount of power generated by the photovoltaic power generation device. Things.

Further, the present invention is the above-mentioned independent type photovoltaic power generation system, wherein charging of an arbitrary number of storage batteries is performed by sequentially selecting another storage battery when the storage battery to be charged is fully charged. , For all storage batteries.

Further, the present invention is the above-mentioned stand-alone photovoltaic power generation system, wherein the power storage device is either an electric double layer capacitor or an electrolytic capacitor, and the plurality of storage batteries are N
Either an i-MH storage battery or a Ni-Cd storage battery, and the plurality of chargers include means for performing constant current charging.

Further, the present invention is the above-mentioned stand-alone photovoltaic power generation system, wherein the power storage device is either an electric double layer capacitor or an electrolytic capacitor, and the plurality of storage batteries are L
a means for performing constant current charging when the storage battery voltage is equal to or lower than the optimum charging voltage, and performing constant voltage charging when the storage battery voltage reaches the optimum charging voltage, which is either an i-ion storage battery or a lead storage battery; It is characterized by having.

Further, in the stand-alone photovoltaic power generation method of the present invention, after the power storage device for storing the power generated by the photovoltaic power generation device is fully charged, the amount of power stored in the power storage device is determined in advance. During the period until the discharge
The plurality of chargers charge an arbitrary number of storage batteries to be charged with a constant current according to a current value at which the storage batteries are most efficiently charged by the power supplied from the solar power generation device or the power storage device. If the amount of power stored in the power storage device reaches a predetermined discharge stop power amount, by stopping the charging of the arbitrary number of storage batteries to be charged by the plurality of chargers, A so-called intermittent pulse for charging the power storage device and, when the power storage device is fully charged, starting charging the arbitrary number of storage batteries to be charged again by the plurality of chargers. It is characterized by performing constant current charging.

Further, in the stand-alone photovoltaic power generation method according to the present invention, after the power storage device for storing the generated power of the photovoltaic power generation device is fully charged, the amount of power stored in the power storage device is determined in advance. During the period until the discharge
The plurality of chargers charge an arbitrary number of storage batteries to be charged at a constant voltage according to a voltage value at which the storage batteries are most efficiently charged by the power supplied from the solar power generation device or the power storage device. If the amount of power stored in the power storage device reaches a predetermined discharge stop power amount, by stopping the charging of the arbitrary number of storage batteries to be charged by the plurality of chargers, A so-called intermittent pulse for charging the power storage device and, when the power storage device is fully charged, starting charging the arbitrary number of storage batteries to be charged again by the plurality of chargers. It is characterized by performing constant current charging.

Further, in the stand-alone photovoltaic power generation method of the present invention, after the power storage device for storing the generated power of the photovoltaic power generation device is fully charged, the amount of power stored in the power storage device is determined in advance. A period in which the plurality of chargers charge an arbitrary number of storage batteries to be charged at a constant current by the power supplied from the photovoltaic power generation device or the power storage device until the discharge stop power amount is reached. And when the amount of power stored in the power storage device reaches a predetermined amount of power to stop discharging, the charging of the arbitrary number of storage batteries to be charged by the plurality of chargers is stopped, and the power Charging the storage device; selecting a desired number of storage batteries to be charged by a plurality of chargers when the power storage device is fully charged; and starting charging; Removing the fully charged storage batteries from the arbitrary number of storage batteries to be charged from the charging targets, selecting a new storage battery to be charged from the storage batteries that have not been charged, and starting charging. It is characterized by having.

According to the present invention, in the above-mentioned independent solar power generation method, power is supplied to a load by turning on a switch connected to an output side of a storage battery other than an arbitrary number of storage batteries to be charged. It is characterized by the following.

Further, according to the present invention, in the above-mentioned independent solar power generation method, when power is supplied to the load, when the storage battery to be charged is charged, the power is supplied to the output side of the storage battery to be charged. It is performed by turning on the connected switch, and when the storage battery to be charged is not charged, the switch connected to the output side of the storage battery to be charged is turned off, It is performed by turning on a switch connected to the output side of a storage battery other than the storage battery to be charged.

[0024]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram of a stand-alone photovoltaic power generation system according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a solar cell as an example of a photovoltaic power generator, and reference numeral 2 denotes a power converter. Converter, 3 is a power detector, 4 is an electric double layer capacitor (EDL) as an example of a power storage device.
C), 5 is a load, 6-1 to 6-p to 6-n are chargers, 7
-1 to 7-q to 7-n are Ni-MH batteries (nickel-metal hydride batteries), 8-1 to 8-r to 8-n are backflow blocking diodes, and 9-1 to 9-s to 9-n are switches It is. n is the number of connected storage batteries.

That is, the solar cell 1 generates electric power by sunlight. The output side of solar cell 1 is connected to the input side of converter 2, and the output side of converter 2 is connected to EDLC 4 and chargers 6-1 to 6-p to 6-n via power detector 3.
Of the chargers 6-1 to 6 are connected in parallel, respectively.
The output sides of -p to 6-n correspond to Ni-MH, respectively.
Storage batteries 7-1 to 7-q to 7-n are connected. The Ni
-Loads are applied to the MH storage batteries 7-1 to 7-q to 7-n via the corresponding reverse current blocking diodes 8-1 to 8-r to 8-n and the switches 9-1 to 9-s to 9-n. 5 are commonly connected.

The converter 2 has a maximum power follow-up control function for constantly changing the voltage and the current so that the maximum power can be obtained from the solar cell 1.
Has a function to generate electricity under the condition that converts sunlight into electric power most efficiently. Converter 2 also has a function of making the output voltage a desired constant voltage.

After the EDLC 4 is fully charged, the EDLC 4
During the period until the voltage of the battery 4 reaches the predetermined discharge stop voltage V1, the chargers 6-1 to 6-p to 6-n
Alternatively, Ni-
Of the MH storage batteries 7-1 to 7-q to 7-n, m (1 ≦ m ≦ n) Ni-MH storage batteries to be charged are charged at a constant current or a constant voltage, and the voltage of the EDLC 4 is predetermined. When the discharge stop voltage V1 is reached, charging of the m Ni-MH storage batteries 7-1 to 7-q to 7-n to be charged is stopped. Thereby, the Ni-MH storage batteries 7-1 to 7-q to 7
When −n is not charged, the power generated by the solar cell 1 is consumed for charging the EDLC 4,
When the EDLC 4 is fully charged, the chargers 6-1 to 6-
It is characterized by executing so-called intermittent pulsed constant-current charging, in which m m Ni-MH storage batteries 7-1 to 7-q to 7-n to be charged from p to 6-n are charged again. I do.

If at least one of the m Ni-MH storage batteries to be charged has reached a full charge, it is excluded from the charging target and another Ni-MH storage battery not to be charged. Are sequentially charged in order.

The power supply to the load 5 is performed by the Ni-MH storage battery 7-
When charging of 1 to 7-q to 7-n is not performed, n
Out of the Ni-MH storage batteries 7-1 to 7-q to 7-n which are not to be charged, the reverse current blocking diodes 8-1 to 8-r to 8-n; This is performed via the switches 9-1 to 9-s to 9-n. When the Ni-MH storage batteries 7-1 to 7-q to 7-n are being charged, the chargers 6-1 to 9-n are simultaneously operated. Power is supplied to the load 5 from 6-p to 6-n.

The capacity of the solar cell 1 and the chargers 6-1 to 6-p
6-n and Ni-MH storage batteries 7-1 to 7-q to 7-n
, The number of individual Ni-MH storage batteries, the number m of Ni-MH storage batteries to be charged at one time, and the like are set as follows, for example.

When the capacity of the load 5 is, for example, 30 W and power supply is required all night, the capacity of the solar cell 1 needs to be about 350 W. If the number of days of continuous sunshine compensation is 15 days, Ni-
The total capacity of the MH storage batteries 7-1 to 7-q to 7-n is 10.8.
kWh (12V-900Ah). Chargers 6-1 to
When 6-p to 6-n can be formed using inexpensive and small parts, the current value is about 9.0 A, and the Ni-MH storage battery 7-
When the amount of current that can most efficiently charge 1 to 7-q to 7-n is 0.1 CA, the capacity of each Ni-MH storage battery is 12 V-90 Ah, and n = 10.

When the solar cell 1 generates power at the rated power, the current used for charging is 320 W minus the load power, and about 130 W is required to charge one Ni-MH storage battery (12 V, 90 Ah) by 0.1 CA. Because
In order to always use solar cells efficiently without generating excess generated power, it is necessary to satisfy the following condition: (generated power of solar cell) <(load power, power required for charging) ≧ 3 (1
30W × 3 = 390W).

Next, the operation of the stand-alone photovoltaic power generation system when m = 3 will be described with reference to FIG. 3, FIG. 4, and FIG. FIG. 3 is a characteristic diagram showing a relationship between a power generation amount of a solar cell and a charge / discharge operation of an electric double layer capacitor and a storage battery in a stand-alone photovoltaic power generation system according to an embodiment of the present invention. It is a flowchart which shows the charging / discharging operation | movement of Ni-MH storage battery and EDLC in the stand-alone photovoltaic power generation system which is one Example of this invention.

A maximum of 35 from the solar cell 1 during the daytime in fine weather
0W generated power is obtained. Ni-MH storage battery 7-1
7-q to 7-n are each 12V-90Ah. N
Charge order f of i-MH storage batteries 7-1 to 7-q to 7-n_n
(N is the Ni-MH storage battery number),
When the values of m and n are m = 3 and n = 10, respectively,
Ni-MH batteries to be charged in the initial state are 7-1 to 7-
3, the charging order f _nIs f₁= 1, f_Two=
2, f_Three= 3, while the Ni-MH charge to be discharged
The pond is 7-4 to 7-10, and the charging order f_nAre each
f_Four= 4 to f_Ten= 10.

[0036] switch corresponding to the Ni-MH battery is 7-4～7-10 a charging order f _n ≧ 4 9-4~9-1
0 is turned on (ON) (step ST2 in FIG. 4), and power is supplied to the load 5 (period A in FIG. 3). The converter 2 is operated in the maximum power follow-up control (MPPT mode) (step ST3).
The EDLC 4 of V-50F is charged (period A in FIG. 3). When the output power P of the solar cell 1 is 350 W, the EDLC 4 reaches a full charge in about one minute. EDL
Full charge of C4 is determined by the fact that the EDLC voltage Ve has become equal to the maximum rated voltage Vh (step ST4). N
The power required to supply power to the i-MH storage battery and the load falls below the power generation P of the solar cell 1, and the power detector 3 measures the generated power P so that the generated power is not lost, and performs charging at the same time. The number of Ni-MH batteries is determined (step S
T5). The operation in the maximum power follow-up control (MPPT mode) is performed because the generated power P of the solar cell 1 is not constant as shown in FIG. 3, so that the current and voltage are controlled so that the power can be maximized at each time. To do that.

At step ST5, the power generated by the solar cell 1
Is less than the power required to charge the load and the two Ni-MH batteries.
If it is determined to be above (P> 310W), three Ni-MH
Charge order f for charging storage batteries simultaneously_n≦ 3
Operate the charger corresponding to the existing Ni-MH storage battery (ON)
(Step ST6), and the generated power P is supplied to the load.
Charging order f_nNi-MH storage battery with ≦ 3
Is turned on (ON) (step S
T7). Supplied from solar cell 1 or EDLC4
Charge order f by electric power₁~ F_ThreeNi-MH storage battery 7
-1 ~ 7-3 Is charged at a constant current (period B in FIG. 3),
Load 5 also has a reverse current blocking diode 8-1 8-3 and Sui
Switch 9-1 -9-3.

In step ST8, the Ni-MH storage battery 7-1 having a charging order of f _{1 to} f ₃ is stored. If the EDLC voltage Ve becomes equal to or lower than the discharge suspending voltage V1 in step ST9 before 〜7-3 reaches the full charge, the charging order is N or less.
The switch corresponding to the i-MH storage battery is turned off (OFF) (step ST10), and the Ni-M having a charging order of 3 or less is set.
The charger corresponding to the H storage battery is stopped (OFF) (step ST11). Thereby, the EDLC 4 is charged again (period A in FIG. 3), and after the EDLC 4 is fully charged (step ST4), the number of Ni-MH storage batteries to be simultaneously charged again is determined in step ST5.

On the other hand, in step ST8, the charging order is changed from f ₁ to f ₁ .
If at least one of Ni-MH battery 7-1 to 7-3 is a f ₃ is fully charged, Ni-M, which is fully charged
A charger that corresponds to H-acid battery and off (OFF) (step ST12), the charging rank f _n of Ni-MH battery that is fully charged and f _n = 10 (step ST13).
Also for all Ni-MH battery that did not reach the fully charged, it gives again 1-9 charging order from ascending order of charging rank f _n (step ST14), new charging rank f _n =
The charger corresponding to the Ni-MH storage battery that has become 3 is turned on (ON) (step ST15). By performing such control, the number of Ni-MH storage batteries to be charged is always fixed at three, and it is possible to charge and discharge all Ni-MH storage batteries in order.

If it is determined in step ST5 that P.ltoreq.310W, the number of rechargeable batteries to be charged again is determined in step ST16.
The process proceeds to step ST17 to step ST28 in the same manner as in step ST6 to step ST15. If the number is one, the process proceeds to step ST29, and step ST29 to step ST40 are performed in step ST6 to step ST40.
The processing is performed in the same manner as in step ST15.

By performing the repetitive charge / discharge control as described above, a plurality of Ni-MH storage batteries 7-1 to 7-q to 7-n
Can be intermittently charged with a desired current and voltage, so that the Ni-MH storage batteries 7-1 to 7-q to 7
−n becomes easy to detect full charge, and the Ni-MH storage battery 7−
It is possible to avoid dangers of overcharging and insufficient charging of 1 to 7-q to 7-n. Also, by dividing the Ni-MH storage battery, the current flowing through the charger can be reduced, and the size and cost of the charger can be reduced.

Although the embodiments of the present invention have been described above, the present invention is not necessarily limited to the above-described means and methods, but a range that achieves the object of the present invention and has the effects of the present invention. Can be appropriately changed and implemented.

[0043]

As described above, according to the present invention, a large-capacity photovoltaic power generator is provided because the power generated by the photovoltaic power generator is temporarily stored in the electric double layer capacitor and then a plurality of storage batteries are charged. It becomes possible to charge a plurality of storage batteries with a desired current / voltage without using them. Therefore, detection of full charge becomes easy, and dangers such as overcharging and insufficient charging of a plurality of storage batteries can be avoided. Also, dividing the storage battery reduces the current flowing through the charger,
It is also possible to reduce the size and cost of the charger.

[Brief description of the drawings]

FIG. 1 is a block diagram of a stand-alone photovoltaic power generation system according to an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional stand-alone photovoltaic power generation system.

FIG. 3 is a characteristic diagram showing a relationship between a power generation amount of a solar cell and a charge / discharge operation of an electric double layer capacitor and a storage battery in a stand-alone photovoltaic power generation system according to an embodiment of the present invention.

FIG. 4 is a flowchart showing a charge / discharge operation of a Ni-MH storage battery and an electric double layer capacitor of the stand-alone photovoltaic power generation system according to one embodiment of the present invention.

FIG. 5 is a flowchart showing a charging / discharging operation of the Ni-MH storage battery and the electric double layer capacitor of the stand-alone photovoltaic power generation system according to one embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 solar cell 2 converter 3 power detector 4 electric double layer capacitor 5 load 6-1 to 6-p to 6-n charger 7-1 to 7-q to 7-n Ni-MH storage battery 8-1 to 8- r ~ 8-n Backflow prevention diode 9-1 ~ 9-s ~ 9-n Switch 11 Photovoltaic power generator 12 Load or power converter 13 Charger 14 Power storage device 15-1, 15-2, 15-3 Backflow Blocking diode

Continuing on the front page (72) Inventor Yosuke Nozaki 2-3-1 Otemachi, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Kenji Tanino 1-1-18-1 Takada, Toshima-ku, Tokyo Origin Inside Electric Co., Ltd. (72) Inventor Makoto Yamamoto 1-18-1 Takada, Toshima-ku, Tokyo Origin Electric Co., Ltd. F-term (reference) 5F051 BA11 JA07 JA17 KA03 5G003 AA06 BA04 DA05 DA18 5G065 BA06 DA07 EA03 NA06

Claims (15)

[Claims] A power generation device connected to an output of the power generation device; a power storage device connected to an output of the power generation device; A plurality of chargers connected to the output of the power conversion device and the power storage device, a plurality of storage batteries respectively connected to the chargers, and a load connected to the outputs of the plurality of storage batteries. A stand-alone photovoltaic power generation system. 2. The stand-alone photovoltaic power generation system according to claim 1, wherein the load is connected to outputs of the plurality of storage batteries via switches. 3. The stand-alone photovoltaic power generation system according to claim 1, wherein the load is connected to outputs of the plurality of storage batteries via a backflow prevention diode. 4. The stand-alone photovoltaic power generation system according to claim 1, wherein the power converter performs a power generation operation under a condition where the photovoltaic power generator converts sunlight into power most efficiently. An independent photovoltaic power generation system having a tracking control function. 5. The stand-alone photovoltaic power generation system according to claim 1, wherein the power converter is overcharged when the power storage device is fully charged. A stand-alone photovoltaic power generation system, comprising: 6. The stand-alone photovoltaic power generation system according to claim 1, wherein the plurality of storage batteries are provided.
A stand-alone photovoltaic power generation system comprising means for selecting an arbitrary number of storage batteries and operating a charger having an output connected to the arbitrary number of storage batteries to perform charging. 7. The stand-alone photovoltaic power generation system according to claim 6, wherein charging of an arbitrary number of storage batteries is performed by changing the number of storage batteries to be selected according to the amount of power generated by the photovoltaic power generation device. Independent photovoltaic power generation system. 8. The stand-alone photovoltaic power generation system according to claim 6, wherein charging of an arbitrary number of storage batteries sequentially selects another storage battery when the storage battery to be charged is fully charged. A stand-alone photovoltaic power generation system characterized by being executed for all of the plurality of storage batteries. 9. The stand-alone photovoltaic power generation system according to claim 1, wherein the power storage device is one of an electric double layer capacitor and an electrolytic capacitor, and the plurality of storage batteries are Ni-MH. Storage battery or Ni-Cd
A stand-alone photovoltaic power generation system, which is any one of storage batteries, wherein the plurality of chargers include means for performing constant current charging. 10. The stand-alone photovoltaic power generation system according to claim 1, wherein the power storage device is one of an electric double layer capacitor and an electrolytic capacitor, and the plurality of storage batteries are Li-ion storage batteries. Alternatively, the plurality of chargers include means for performing constant current charging when the storage battery voltage is equal to or lower than the optimum charging voltage, and performing constant voltage charging when the storage battery voltage reaches the optimum charging voltage. A stand-alone photovoltaic power generation system characterized in that: 11. A period from when a power storage device that stores power generated by a photovoltaic power generation device is fully charged to when the amount of power stored in the power storage device reaches a predetermined discharge suspension power amount. In addition, the plurality of chargers, by the power supplied from the solar power generation device or the power storage device, a constant number of storage batteries to be charged at a constant current by the current value at which the storage battery is most efficiently charged Charging, when the amount of power stored in the power storage device reaches a predetermined discharge stop power amount, stopping charging of the arbitrary number of storage batteries to be charged by the plurality of chargers; By charging the power storage device,
When the power storage device is fully charged, the plurality of chargers execute so-called intermittent pulsed constant-current charging to start charging the arbitrary number of storage batteries to be charged again. Independent solar power generation method. 12. A period from when the power storage device for storing the generated power of the photovoltaic power generation device is fully charged to when the amount of power stored in the power storage device reaches a predetermined discharge suspension power amount. In addition, a plurality of chargers, by the power supplied from the photovoltaic power generation device or the power storage device, a constant number of storage batteries to be charged at a constant voltage by the voltage value at which the storage batteries are most efficiently charged. Charging, when the amount of power stored in the power storage device reaches a predetermined discharge stop power amount, stopping charging of the arbitrary number of storage batteries to be charged by the plurality of chargers; By charging the power storage device,
When the power storage device is fully charged, the plurality of chargers execute so-called intermittent pulsed constant-current charging to start charging the arbitrary number of storage batteries to be charged again. Independent solar power generation method. 13. A period from when the power storage device for storing the generated power of the photovoltaic power generation device is fully charged to when the amount of power stored in the power storage device reaches a predetermined discharge stop power amount. A plurality of chargers, by the power supplied from the solar power generation device or the power storage device,
Charging an arbitrary number of storage batteries to be charged with a constant current; and, when the amount of power stored in the power storage device reaches a predetermined discharge stop power amount, the plurality of battery chargers Stopping charging of any number of storage batteries to be charged and charging the power storage device; and, when the power storage device is fully charged, any charging target by a plurality of chargers. Selecting the number of storage batteries and starting charging; removing the fully charged storage batteries from the arbitrary number of storage batteries to be charged from the charging targets, and newly selecting from the storage batteries that were not to be charged. Selecting a storage battery to be charged and starting charging. 14. The power supply to a load is performed by turning on a switch connected to an output side of a storage battery other than an arbitrary number of storage batteries to be charged.
14. The independent solar power generation method according to 1, 12, or 13. 15. The power supply to the load is performed by turning on a switch connected to the output side of the storage battery to be charged when the storage battery to be charged is charged. When the storage battery to be charged is not charged, a switch connected to the output side of the storage battery to be charged is turned off, and the output of storage batteries other than the storage battery to be charged is turned off. 14. The method according to claim 11, 12 or 13, wherein the method is performed by turning on a switch connected to the side.