JPH1146455A - Solar cell power supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply from which voltage can be obtained with stability even in a day with less sunshine and which is capable of supplying a load with voltage with stability for a long time. SOLUTION: A plurality of power storage devices 2 with a small capacity relative to the energy generated in a solar cell 1 are installed, and the terminal voltage of each of the power storage devices 2 is kept detected through a voltage detection circuit 4. Based on the detected terminal voltages, the charging state of each of the power storage devices 2 is judged, and a switching circuit 5 connected in series with the power storage devices 2 is controlled. Through this control, the power storage devices 2 are charged with power from the solar cell 1 one by one so that the terminal voltage becomes a reference value or above when charging. When a load is in operation, the charged power storage devices 2 are sequentially made to output one by one, thereby continuously inputting a voltage equal to or above the reference value to a constant voltage circuit 6. The voltage is there boosted to a certain value, and supplied to the load 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar cell type power supply suitably used for a self-luminous road tack or a road sign using a light emitting diode or the like.

[0002]

2. Description of the Related Art Conventionally, a solar cell type power supply device used for a self-luminous road tack or a road sign using a light emitting diode or the like directly supplies power output from a solar cell to a load such as a light emitting diode. Instead, generally, the power output from the solar cell is once charged into a power storage device, and the output voltage from the charging device is input to a constant voltage circuit, and the constant voltage circuit boosts the voltage to a stable constant voltage to load the load. To be supplied. As such a solar battery type power supply device, a device which charges all the power of a solar battery to one large-capacity power storage device or a plurality of small-capacity power storage devices connected in parallel to increase the capacity is used. Some power storage devices are charged at the same time. Further, in the solar battery type power supply device as described above, in order to boost the load voltage required by the load by the constant voltage circuit, the voltage input to the constant voltage circuit from the power storage device, that is, the terminal voltage of the power storage device is used. The load voltage must be equal to or higher than the reference value. If the terminal voltage of the power storage device becomes equal to or lower than the reference value and the voltage difference between the terminal voltage of the power storage device and the load voltage increases, the voltage cannot be boosted well.

[0003]

However, when the capacity of a power storage device is increased for both a device that stores all power in one power storage device and a device that stores power in a plurality of power storage devices connected in parallel at the same time, discharge occurs. Although the time until the battery becomes unusable becomes longer, it takes time to charge until the terminal voltage exceeds the reference value at which the constant voltage circuit operates well, especially when the sunshine is low on consecutive days. There is a problem that the terminal voltage does not exceed the reference value and a stable voltage cannot be obtained during that time. Conversely, when the capacitance is reduced, the charging time is shortened until the terminal voltage becomes higher than the reference value.However, when the voltage is reduced by discharging in a short time and the voltage becomes lower than the reference value, the constant voltage circuit operates well. Therefore, there is a problem that a stabilized voltage cannot be obtained.

Accordingly, the present invention solves the above-mentioned problems, and provides a solar cell type power supply device which can obtain a stable voltage even on a day with a small amount of sunlight and can supply a stable voltage to a load for a long time. It will not be provided.

[0005]

In order to achieve the above object, the present invention has the following arrangement. That is, in the solar battery type power supply device according to the present invention, the power output from the solar battery is charged in the power storage device, the output voltage from the power storage device is input to the constant voltage circuit, and the voltage is made constant by the constant voltage circuit. A solar battery type power supply device adapted to be supplied to a load, wherein a plurality of power storage devices having a small capacity with respect to the amount of power generated by the solar cell are provided, and a switch circuit is connected to each power storage device in series, and A voltage detection circuit is provided for detecting a terminal voltage of each power storage device to determine a state of charge, a switch circuit is controlled based on the terminal voltage detected by the voltage detection circuit, and a terminal voltage is applied to each power storage device. The power of the solar cells is charged one by one in order so that is equal to or higher than the reference value, and the voltage equal to or higher than the reference value is continuously output by outputting the charged power storage devices one by one in order. It is characterized in that adapted to be inputted to the road.

The reference value is a lower limit voltage in a range of an input voltage that can be boosted to a constant voltage by a constant voltage circuit, and depends on a load voltage required by a load and characteristics of the constant voltage circuit. However, the rated voltage of the power storage device used may be set as the reference value. When the voltage from the power storage device input to the constant voltage circuit is equal to or higher than the reference value, the voltage can be boosted to a constant voltage by the constant voltage circuit, and when the voltage is lower than the reference value, the voltage cannot be stably increased.

According to the present invention, a plurality of power storage devices having a small capacity with respect to the amount of power generated by a solar cell are provided, and the terminal voltage of each of the power storage devices is constantly detected by a voltage detection circuit. The state of charge of each power storage device is determined based on the detected terminal voltage, and a switch circuit connected in series to each power storage device is controlled. By this control, at the time of charging, the power of the solar cells is sequentially charged one by one so that the terminal voltage of each power storage device becomes equal to or higher than the reference value. In addition, during the operation of the load, the charged power storage devices are sequentially output one by one so that a voltage equal to or higher than the reference value is continuously input to the constant voltage circuit and supplied to the load.

Therefore, even on a day when the amount of sunlight is small, the terminal voltages of all the power storage devices do not become voltages higher than the reference value. The power storage devices are charged one by one so as to have a voltage equal to or higher than the reference value one by one, and the power storage devices thus charged at or above the reference value are connected to one power storage device in accordance with the load consumption. The charging power is continuously supplied to the load from the power storage device to other power storage devices one by one.

As described above, a plurality of power storage devices having a small capacity with respect to the amount of power generated by the solar cell are provided, and when charging, each of the power storage devices is charged one by one, and the charged power is supplied to a load. In this case, the charging power is supplied to the load one by one, so that a stable voltage can be obtained even when the amount of sunlight is small, and a stable voltage can be supplied to the load for a long time. it can.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention.

In the drawings, reference numeral 1 denotes a solar cell, and a suitable solar cell such as a monocrystalline or polycrystalline crystalline silicon solar cell, an amorphous amorphous silicon solar cell, or a compound semiconductor solar cell is used. It is not limited.

Reference numeral 2 denotes a power storage device for charging the electric power output from the solar cell 1, which is generally a lead storage battery or Ni-
A storage battery such as a Cd battery or a capacitor such as an electric double layer capacitor is used. A plurality of power storage devices 2 each having a capacity smaller than the power generation amount of the solar cell 1 are used. In general, the total capacity of the plurality of power storage devices 2 is approximately equivalent to the power generation amount of the solar cell 1. However, the present invention is not particularly limited.
Are charged one by one without charging them at the same time. Therefore, any power storage device 2 can be charged as quickly as possible.

Reference numeral 3 denotes a backflow prevention diode connected between the solar cell 1 and the power storage device 2, such as at night when the voltage output from the solar cell 1 becomes lower than the voltage of the power storage device 2.
This is for preventing a current from flowing backward from the power storage device 2 to the solar cell 1 side.

Reference numeral 4 denotes a voltage detection circuit connected to each power storage device 2, which detects a terminal voltage of each power storage device 2, respectively.
The state of charge of each power storage device 2, that is, the necessity of charging is determined by comparing with a preset reference value.

Reference numeral 5 denotes a switch circuit, which is connected in series to each power storage device 2, and each power storage device 2 is individually controlled by the switch circuit 5. That is, based on the terminal voltage of each power storage device 2 detected by voltage detection circuit 4, switch circuit 5 is controlled for each power storage device 2. And
When charging, the power storage device 2 whose terminal voltage is equal to or lower than the reference value
Are determined, and the power of the solar cells 1 is sequentially charged from one power storage device 2 to another power storage device 2 one by one such that the terminal voltage becomes equal to or higher than the reference value.

Also, when supplying the charging power to the load, the power storage devices 2 whose terminal voltage is equal to or higher than the reference value are determined, and for those power storage devices 2, first, the output voltage of one power storage device 2 will be described later. It is input to the constant voltage circuit 6 and the load 7
Supplied to When the power of the one power storage device 2 is consumed by the load 7 and the voltage detection circuit 4 determines that the terminal voltage has become equal to or lower than the reference value, the switch circuit 5
The output voltage of another power storage device 2 whose terminal voltage is equal to or higher than the reference value is input to the constant voltage circuit 6 and supplied to the load 7. The power storage device 2 thus charged
Are sequentially output from one power storage device 2 to another power storage device 2 one by one, so that the voltage equal to or higher than the reference value continues until the power of all charged power storage devices 2 is consumed. The signal is input to the circuit 6 and supplied to the load 7. Note that the reference value may be set to a lower limit voltage within a range of an input voltage that can be supplied to the load 7 by boosting the voltage to a constant voltage by the constant voltage circuit 6 operating satisfactorily. The voltage may be set, and the voltage value is set as appropriate.

Reference numeral 6 denotes a constant voltage circuit including a diode 61 and a coil 62, and reference numeral 7 denotes a load such as a light emitting diode.
The constant voltage circuit 6 detects a voltage fluctuation of the charging power input from the power storage device 2 with a transistor or the like, stabilizes the voltage, constantly boosts the voltage to a constant voltage, and supplies the voltage to the load 7. It can operate stably with the constant voltage.

In this embodiment, with such a configuration, based on the terminal voltage detected by the voltage detection circuit 4, the power storage device 2 whose terminal voltage is equal to or lower than the reference value is switched from one power storage device 2 to another according to the amount of sunlight. The power storage devices 2 are charged one by one so that the voltage becomes higher than the reference value. In addition, as for the power storage devices 2 that have been charged to the reference value or more, the charging power is sequentially transferred from the one power storage device 2 to the other power storage devices 2 one by one in accordance with the load consumption. Supplied.

[0019]

According to the present invention, a plurality of power storage devices having a small capacity with respect to the amount of power generated by a solar cell are provided, and when charging, each of the power storage devices is charged one by one and the charged power is reduced. When supplying power to the load, the charging power is supplied to the load one by one, so that a stable voltage can be obtained even on a day with little sunlight, and a stable voltage can be obtained for a long time. Can be supplied to the load.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 solar cell 2 power storage device 3 backflow prevention diode 4 voltage detection circuit 5 switch circuit 6 constant voltage circuit 7 load

Claims (1)

[Claims] An electric power output from a solar battery is charged in a power storage device, an output voltage from the power storage device is input to a constant voltage circuit, and a constant voltage is supplied to the load by the constant voltage circuit. A solar powered power supply made,
A plurality of power storage devices having a small capacity with respect to the amount of power generated by the solar cell are provided, a switch circuit is connected to each power storage device in series, and a voltage for detecting a terminal voltage of each power storage device to determine a charging state. A detection circuit is provided, the switch circuit is controlled based on the terminal voltage detected by the voltage detection circuit, and the power of the solar cells is sequentially charged one by one so that the terminal voltage becomes equal to or higher than the reference value for each power storage device. And a power supply device that outputs charged power storage devices one by one in order, so that a voltage equal to or higher than a reference value is continuously input to a constant voltage circuit.