JP2001045677A - Power supplying device using solar cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively utilize sunlight and a rechargeable battery by optimum charge and discharge by charging a specific pair of rechargeable batteries with the output of a solar cell, by discharging a specific rechargeable battery in the other pairs, and by providing a charge and discharge control circuit for changing the rechargeable battery to be charged or discharged at specific time. SOLUTION: When one of rechargeable batteries 1 and 2 is charged by a charge and discharge control circuit 4, the other supplies power to a DC load 5. When charge is started by a solar cell 3 after the sun rises, the rechargeable battery with a smaller amount of recharge out of the rechargeable batteries 1 and 2 is charged. When the first rechargeable battery (for example, the rechargeable battery 1) is fully charged, or the amount of recharge of the rechargeable battery (for example, the rechargeable battery 2) during discharge becomes zero due to consumption by the DC load 5, the rechargeable battery 1 being charged is switched to discharge and the rechargeable battery 2 being discharged is switched to discharge, thus achieving optimum charge and discharge, and hence increasing the utilization efficiency of the rechargeable battery and sunlight.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device using a solar cell, and more particularly to a power supply device using a solar cell, which charges a storage battery with a solar cell and supplies power from the storage battery to a load.

[0002]

2. Description of the Related Art As a conventional storage battery charger, Japanese Patent Application Laid-Open No.
Japanese Patent Application Laid-Open No. 7-88836 discloses one storage battery that uses a first charger that inputs a solar cell and a second charger that inputs a commercial AC. Further, Japanese Patent No. 2884187 discloses a solar cell utilizing device provided with an additional connecting portion for deriving an electromotive force of the solar cell in order to add a secondary storage battery to the parent storage battery. .

[0003]

However, in the former technique, since only one storage battery is charged by the solar battery, if the storage amount of the storage battery is reduced, the power from the storage battery cannot be used. There was a problem that it would.

In the latter technique, the storage battery of the master unit and the storage battery of the slave unit are connected in parallel and charge and discharge at the same timing. There was a problem that it became impossible to use. The present invention has been made in view of such a problem, and an object of the present invention is to provide a solar cell-based power supply device that enables effective use of sunlight and a storage battery through optimal charging and discharging. .

[0005]

According to the present invention, there is provided a power supply apparatus utilizing solar cells, wherein a predetermined set of the storage batteries is charged by a solar cell, a plurality of sets of storage batteries, and the output of the solar cells.
And a charge / discharge control circuit for changing the storage battery to be charged or discharged at a predetermined time by discharging the storage battery of the other set.

[0006] Also, by converting the alternating current of the commercial power supply to direct current,
By providing the AC / DC converter that supplies the charge / discharge control circuit, when the solar cell is insufficiently charged, the charge amount can be supplemented with commercial power. Further, by providing a DC-AC converter that converts the DC output of the storage battery discharged under the control of the charge / discharge control circuit into AC and supplies the AC load to an AC load, solar cells, time-limited power such as midnight power,
It can always be used for ordinary power lines and the like.

[0007]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. [First Embodiment] FIG. 1 is a diagram showing a configuration of a solar cell power supply device according to an embodiment of the present invention. The solar cell 3 and the two storage batteries 1 and 2 are connected to a charge / discharge control circuit 4, and a DC load 5 is connected to the charge / discharge control circuit 4 as a load.

The charge amounts of the two storage batteries 1 and 2 are monitored by a charge / discharge control circuit 4, so that optimal charge / discharge is performed. When one of the storage batteries 1 and 2 is in a charged state, the other supplies power to the DC load 5. When the solar battery 3 starts charging as the sun goes up, the charging is performed from the one with the smaller amount of charge of the two storage batteries 1 and 2.

When the first storage battery (for example, storage battery 1) is fully charged due to sufficient sunlight, or the amount of storage of the storage battery (for example, storage battery 2) consumed by the DC load 5 and being discharged becomes zero. In this case, the storage battery 1 that has been charged is switched to discharging, and the storage battery 2 that has been discharged is switched to charging. Similarly, when the storage battery 2 is fully charged, or when the storage amount of the storage battery 1 being consumed by the DC load 5 and being discharged becomes 0, the charged storage battery 2 is discharged to discharge. The storage battery 1 that has been operated is switched to charging. FIG. 2 is a time chart for explaining the operation of the first embodiment. The numbers 0 to 18 indicate time, and 1
The day indicates the fine weather and the second day is cloudy, and the width of the rectangle of “photovoltaic power generation” conceptually indicates the amount of power generated by the solar cell 3.

On the first day, the storage battery 1 is discharged until 0 to 6 o'clock, and when the storage amount of the storage battery 1 becomes 0 without waiting for the morning (6 o'clock), the storage battery 2 is switched to discharge. When the sun rises after 6:00 and charging by the solar cell 3 starts,
Since the storage amount of the storage battery 1 remains 0 and the storage amount of the storage battery 1 is smaller, the storage battery 1 is charged by the solar battery 3 in the daytime after 6:00 to 18:00, and the storage battery 1 is around 15:00.
Since the solar charge of the battery has reached 100%, the storage battery 2 is charged and, at the same time, the storage battery 1 is switched to discharge. On the second day, since the storage amount of the storage battery 2 is smaller, charging of the storage battery 2 by solar power generation is started. At this time, the discharge in the storage battery 1 has been continued from the first day. In FIG. 2, the storage batteries 1 and 2 may be exchanged.

[Second Embodiment] In addition to the first embodiment, a commercial power source (AC200V) 6 with a midnight power contract
An AC / DC converter 7 for use as a charging power source for the power supply is connected to the charge / discharge control circuit 4. In the midnight power time zone, the storage battery (for example, the storage battery 1) having the larger storage amount is charged with the midnight power from the viewpoint of preferential use of solar power generation. When the storage battery that has been charged is fully charged, charging by midnight power is stopped. When the charged amount of the discharged storage battery (for example, storage battery 2) becomes 0, or when the chargeable time by the solar cell is reached, the charged or fully charged storage battery 1 is discharged to discharge. The storage battery 2 that has been used is switched to charging and operated.

FIG. 3 is a time chart for explaining the operation of the second embodiment. FIG. 3 also shows a case where the first day is fine weather and the second day is cloudy. On the first day, when charging with midnight power is started, the storage battery 1 with a small storage amount is discharged, and the storage battery 2 with a large storage amount is discharged at midnight power by 10%.
Charge to 0%. When power generation by the solar cell 3 becomes possible after 6:00, the storage battery 1 is charged and the storage battery 2 is switched to discharge. At about 15:00, when the storage battery 1 is fully charged by solar charging, the storage battery 2 is charged next, and the storage battery 1 is simultaneously switched to discharge. At around 17:00, when solar power generation ends,
The discharge of the storage battery 1 is switched to the discharge of the storage battery 2. This is because the storage battery having a small amount of stored power is first discharged to use solar power generation effectively. On the second day, the storage battery 1 having a large storage amount is charged at 100% with midnight power, and when solar power generation starts after 6:00, the storage battery 1 is switched to discharge and storage battery 2.
And this day, when the solar power generation ends, the storage battery 1
Continue discharging. This is because on this day, the storage amount of the storage battery 1 is small, and the storage battery 1 with the small storage amount is first discharged to effectively utilize the solar power generation. In FIG. 3, the storage batteries 1 and 2 may be exchanged.

Third Embodiment In addition to the first and second embodiments, a general home appliance load 9 is connected to the charge / discharge control circuit 4 via a DC / AC converter 8 as a load. A commercial power supply 10 is connected between the DC / AC converter 8 and the general home appliance load 9 via a changeover switch 11. The storage battery output from the charge / discharge control circuit 4 is converted to AC 100 V AC by the DC / AC converter 8 and can be used in the same manner as a normal power line. When the output of the storage battery is insufficient, the operation is continued by switching to the commercial power supply 10 by the changeover switch 11.

The solar cell power supply device of the present invention is not limited to the above-described embodiment, but can be changed as appropriate. For example, the storage batteries 1 and 2 may have a configuration in which a plurality of single storage batteries are connected to form a storage battery group. Further, the present invention is not limited to the two sets of the storage batteries 1 and 2, and an arbitrary plurality of sets of three or more sets of storage batteries may be charged and discharged in order.

[0015]

As described in detail above, according to the present invention, optimal charging / discharging can be performed, the utilization efficiency of a storage battery and sunlight can be improved, and unstable power such as a solar cell can be converted into stable power. Can supply.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a solar cell-based power supply device according to first, second, and third embodiments of the present invention.

FIG. 2 is a time chart for explaining the operation of the first embodiment.

FIG. 3 is a time chart for explaining the operation of the second embodiment.

[Explanation of symbols]

 1, 2 Storage battery 3 Solar cell 4 Charge / discharge control circuit 6, 10 Commercial power supply 7 AC / DC converter 8 DC / AC converter 9 General home appliance load

Claims (3)

[Claims] Claims: 1. A solar cell, a plurality of sets of storage batteries, and charging of a predetermined set of storage batteries by an output of the solar battery;
And a charge / discharge control circuit for changing the storage battery to be charged or discharged at a predetermined time by discharging the predetermined storage battery in the other set. 2. The power supply device using solar cells according to claim 1, further comprising an AC / DC converter for converting AC of commercial power into DC and supplying the DC to the charge / discharge control circuit. 3. A DC / AC converter for converting a DC output of a storage battery discharged under the control of the charge / discharge control circuit into an AC and supplying the AC to an AC load.
Or the power supply device using a solar cell according to 2.