JP2000181556A - Solarlight power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar battery power generation system that can stably supplying power corresponding to the operation of the load even when the quantity of solar radiation is decreased and that can improve the reliability by avoiding the unwanted operation stop of a load. SOLUTION: On the rear side of a solar battery 11 for transducing solar energy to power, a storage battery 14, bidirectional power converting circuit 16 and diode 17 are provided. The bidirectional power converting circuit 16 converts input power from the solar battery 11 and storage battery 14 to AC power and outputs it to the outside. Further, the circuit 16 converts the input power from the outside into DC power and outputs it toward the storage battery 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photovoltaic power generation system provided with a solar cell for converting solar energy into electric power, converting the output of the solar cell into AC power, and supplying it to a commercial AC power supply or a load.

[0002]

2. Description of the Related Art There is a so-called AC module which converts solar energy into DC power by a solar cell, converts the DC power into AC power by an inverter, and supplies the AC power to a commercial AC power supply or a load. An example is shown in FIG.

FIG. 1 shows the structure of the back side of a solar cell (the side not exposed to sunlight), on which an output terminal 2 is provided, an inverter 3 is mounted, and an output terminal 2 is provided.
An electric path is formed from the power supply to the inverter 3 via the diode 4. A commercial AC power supply or an AC load is connected to an output terminal of the inverter 3.

[0004] As an operation mode of the AC module, there are an interconnection operation for supplying electric power to a commercial AC power supply and an independent operation for supplying electric power to an AC load.

[0005]

In the conventional system, in the case of self-sustaining operation, when the amount of solar radiation decreases, the power generated by the solar cell becomes smaller than the current consumption of the AC load, and the operation of the AC load stops. is there.

[0006] The present invention has been made in view of the above circumstances,
The aim is to provide a stable power supply commensurate with the operation of the load even when the amount of solar radiation decreases,
An object of the present invention is to provide a solar cell power generation system capable of avoiding unnecessary operation stop of a load and improving reliability.

[0007]

According to a first aspect of the present invention, there is provided a solar cell power generation system comprising: a solar cell for converting sunlight energy into electric power; a storage battery connected to the solar cell;
A function of having a first terminal connected to the solar cell and the storage battery and having a second terminal for external connection, converting input power to the first terminal into AC power, and outputting the AC power from the second terminal; Bidirectional power conversion means having a function of converting input power to the second terminal into DC power and outputting from the first terminal.

According to a second aspect of the present invention, in the solar cell power generation system according to the first aspect of the present invention, the storage battery and the bidirectional power conversion means are attached to the back side of the solar cell via a heat insulating material.

According to a third aspect of the present invention, there is provided a solar cell power generation system, comprising: a solar cell that converts sunlight energy into electric power;
It has a storage battery connected to the solar cell, a first terminal connected to the solar cell and the storage battery, and a second terminal for external connection, and converts input power to the first terminal into AC power. Bi-directional power conversion means having a function of outputting the DC power from the second terminal and a function of converting the input power to the second terminal into DC power and outputting the DC power from the first terminal, and energizing the storage battery when the storage battery is fully charged. Storage battery monitoring means for shutting off the power supply.

According to a fourth aspect of the present invention, in the solar cell power generation system according to the first aspect, the storage battery, the bidirectional power conversion means, and the storage battery monitoring means are attached to the back side of the solar cell via a heat insulating material.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 11 denotes a solar cell which converts sunlight energy into DC power. The figure shows the configuration of the back side (the side not exposed to sunlight) of the solar cell 11,
The output terminal 12 is led out to the back surface, and a plate-like heat insulating material 13 is attached.

FIG. 2 is a side view of FIG. 1, and a storage battery 14, a storage battery monitoring circuit 15, and a bidirectional power conversion circuit 16 are mounted on a heat insulating material 13. Although a diode 17 to be described later is detached from the heat insulating material 13 in the drawing, it is actually mounted on the heat insulating material 13.

The heat insulating material 13 includes a storage battery 14, a storage battery monitoring circuit 15, a bidirectional power conversion circuit 16, and a diode 1.
7 is prevented from increasing in temperature due to the heat generated by the solar cell 1, and deterioration of each component due to heat is prevented.

The storage battery 14 is connected to the output terminal 12 via a storage battery monitoring circuit 15, and a diode 17 is inserted and connected between the connection between the storage battery monitoring circuit 15 and the output terminal 12.
The diode 17 is connected to the storage battery 14 or the bidirectional power conversion circuit 1.
The flow of current from 6 to the solar cell 11 is prevented. By this prevention, reverse charging of the solar cell 11 is prevented, and deterioration of the solar cell 11 is prevented.

The storage battery monitoring circuit 15 monitors the state of charge of the storage battery 14 and, when fully charged, notifies the user by lighting of the attached light emitting diode (LED) 15a and cuts off the power supply to the storage battery 14. Light emitting diode 15a
Is mounted on the outer peripheral surface of the housing of the storage battery monitoring circuit 15 in an exposed state.

The bidirectional power conversion circuit 16 includes an output terminal 12
(Anode of the diode 17) and a first terminal 16a connected to the storage battery 14 (storage battery monitoring circuit 15) and a second terminal 16b for external connection. The input power to the first terminal 16a is converted into AC power. Convert to the second terminal 16
b) and the function of the inverter operation output from the first terminal 16b and the input power to the second terminal
It has a function of a charging operation (rectifying operation) output from a. Among them, the inverter operation includes a system interconnection operation when supplying power to a commercial AC power supply and an independent operation when supplying power to an AC load.

The bidirectional power conversion circuit 16 includes a changeover switch 16c for selectively setting any one of an inverter operation corresponding to a system interconnection operation, an inverter operation corresponding to an independent operation, and a charging operation (rectifying operation). Prepare.

The second terminal 16b of the bidirectional power conversion circuit 16
Is connected to a commercial AC power supply or an AC load.

Next, the operation of the above configuration will be described.

(1) As shown in FIG. 3, in the interconnection operation in which the commercial AC power supply 20 is connected to the second terminal 16b of the bidirectional power conversion circuit 16, the changeover switch 16c is operated to enable the system interconnection operation. Inverter operation is set.

When the solar cell 11 is exposed to sunlight, DC power is generated from the solar cell 11. This DC power is supplied to the storage battery 14 via the diode 7 and the storage battery monitoring circuit 15.
And is input to the bidirectional power conversion circuit 16 via the diode 7.

In the bidirectional power conversion circuit 16, the input DC power is converted into AC power by switching.
Is output. This output is supplied to the commercial AC power supply 20.

The state of charge of the storage battery 14 is determined by the storage battery monitoring circuit 1.
When the battery is fully charged, the light emitting diode 15a of the storage battery monitoring circuit 15 is turned on and the power supply to the storage battery 14 is cut off. This lighting gives a notification that the battery is fully charged, and prevents overcharging by shutting off the power supply.

When the storage battery 14 is not fully charged, the light emitting diode 15a is turned off and the power supply to the storage battery 14 is restarted.

(2) As shown in FIG. 4, in the independent operation in which the AC load 21 is connected to the second terminal 16b of the bidirectional power conversion circuit 16, the operation of the changeover switch 16c sets the inverter operation corresponding to the independent operation. Is done.

When the solar cell 11 is exposed to sunlight, DC power is generated from the solar cell 11. If the generated power is equal to or larger than the power consumption of the AC load 21, the generated power is equal to the diode 7 and the storage battery monitoring circuit 1.
5, and is input to the bidirectional power conversion circuit 16 via the diode 7.

In the bidirectional power conversion circuit 16, the input DC power is converted into AC power by switching.
Is output. This output is supplied to the AC load 21.

The state of charge of the storage battery 14 is determined by the storage battery monitoring circuit 1.
When the battery is fully charged, the light emitting diode 15a of the storage battery monitoring circuit 15 is turned on and the power supply to the storage battery 14 is cut off. This lighting gives a notification that the battery is fully charged, and prevents overcharging by shutting off the power supply.

When the storage battery 14 is not fully charged, the light emitting diode 15a is turned off, and the power supply to the storage battery 14 is restarted.

When the power generated by the solar cell 11 becomes smaller than the power consumption of the AC load 21 (including the generated power "zero") due to a decrease in the amount of solar radiation, the storage battery 14 is used to compensate for the shortage.
Is discharged, and the discharged power is input to the bidirectional power conversion circuit 16 together with the generated power of the solar cell 11.

In the bidirectional power conversion circuit 16, the input DC power is converted into AC power by switching.
Is output. This output is supplied to the AC load 21.

Thus, irrespective of the decrease in the amount of solar radiation, stable power required for the operation of the AC load 21 is supplied, and unnecessary stoppage of the operation of the AC load 21 is prevented.

(3) As shown in FIG. 5, when the commercial AC power supply 20 is connected to the second terminal 16b of the bidirectional power conversion circuit 16 to perform the charging operation on the storage battery 14, the charging operation is performed by operating the changeover switch 16c. Is set.

That is, in the bidirectional power conversion circuit 16,
AC power input from the commercial AC power supply 20 is converted to DC power and output to the storage battery 14. This DC power is charged in the storage battery 14.

The state of charge of the storage battery 14 is determined by the storage battery monitoring circuit 1.
When the battery is fully charged, the light emitting diode 15a of the storage battery monitoring circuit 15 is turned on and the power supply to the storage battery 14 is cut off. This lighting gives a notification that the battery is fully charged, and prevents overcharging by shutting off the power supply.

When the storage battery 14 is no longer fully charged, the light emitting diode 15a is turned off and power supply to the storage battery 14 is resumed.

(4) As described above, in the self-sustained operation performed by connecting the AC load 21, even if the amount of solar radiation decreases, stable power supply to the AC load 21 is continued by discharging from the storage battery 14. Therefore, unnecessary operation stop of the AC load 21 can be avoided, and high reliability can be secured.

Regarding charging of the storage battery 14, the solar cell 1
In addition to charging from 1, the charging can be performed from the commercial AC power supply 20 by performing the charging operation of the bidirectional power conversion circuit 16. Therefore, a sufficient amount of power can always be stored in the storage battery 14 without being affected by the amount of solar radiation. That is, in the case of the self-sustaining operation, the AC load 2
1, it is possible to continuously supply highly reliable power for a long time.

Since the storage battery monitoring circuit 15 can prevent the storage battery 14 from being overcharged, the life of the storage battery 14 can be extended, which is economical.

The heat insulating material 13 can prevent the temperature of the storage battery 14, the storage battery monitoring circuit 15, the bidirectional power conversion circuit 16, and the diode 17 from rising due to the heat generated by the solar cell 1, so that the heat generated by the respective components Deterioration can be prevented, and the life of the device can be extended.

The present invention is not limited to the above embodiment, but can be variously modified without changing the gist.

[0043]

As described above, according to the present invention, a solar cell for converting sunlight energy into electric power, a storage battery connected to the solar battery, and a first terminal connected to the solar battery and the storage battery are provided. Having a second terminal for external connection, converting input power to the first terminal into AC power and outputting from the second terminal, and converting input power to the second terminal into DC power. Since bidirectional power conversion means having a function of outputting from the first terminal is provided, even if the amount of solar radiation is reduced, stable power supply matching the operation of the load can be performed, and unnecessary stoppage of operation of the load is avoided. Thus, a solar cell power generation system capable of improving reliability can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment.

FIG. 2 is a side view of FIG. 1;

FIG. 3 is a diagram showing a flow of electric power during the interconnection operation of the embodiment.

FIG. 4 is a diagram showing a flow of electric power during the self-sustaining operation of the embodiment.

FIG. 5 is a diagram showing a flow of power during a charging operation of the embodiment.

FIG. 6 is a diagram showing a configuration of a conventional device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Solar cell 12 ... Output terminal 13 ... Heat insulation material 14 ... Storage battery 15 ... Storage battery monitoring circuit 16 ... Bidirectional power conversion circuit 20 ... Commercial AC power supply 21 ... AC load

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahiro Hashiwaki 3-4-1 Shibaura, Minato-ku, Tokyo Inside NTT Facilities, Inc. (72) Inventor Yuji Kawagoe 3-chome Shibaura, Minato-ku, Tokyo No. 1 F-term in NTT Facilities Co., Ltd. (reference) 5G003 AA06 BA01 CC01 DA06 FA01 GB06 5G066 HA30 HB06 HB09 JA01 JB03 5H420 BB03 BB14 CC03 CC06 DD03 EB39 LL10

Claims (4)

[Claims] 1. A solar cell for converting solar energy into electric power, a storage battery connected to the solar cell, and a second terminal for external connection having a first terminal connected to the solar cell and the storage battery And has a function of converting input power to the first terminal into AC power and outputting it from the second terminal, and a function of converting input power to the second terminal into DC power and outputting it from the first terminal. A solar cell power generation system, comprising: bidirectional power conversion means. 2. The solar cell power generation system according to claim 1, wherein the storage battery and the bidirectional power converter are mounted on the back side of the solar cell via a heat insulating material. 3. A solar cell for converting solar energy into electric power, a storage battery connected to the solar cell, and a second terminal for external connection having a first terminal connected to the solar cell and the storage battery. And has a function of converting input power to the first terminal into AC power and outputting it from the second terminal, and a function of converting input power to the second terminal into DC power and outputting it from the first terminal. A solar cell power generation system comprising: a bidirectional power conversion unit; and a storage battery monitoring unit that shuts off power supply to the storage battery when the storage battery is fully charged. 4. The solar cell power generation system according to claim 3, wherein the storage battery, the bidirectional power conversion unit, and the storage battery monitoring unit are mounted on a back side of the solar cell via a heat insulating material. Solar power generation system.