JP2018151857A - Power supply device and power supply control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply device capable of efficiently using solar energy over a wide range from a low illuminance region to a high illuminance region, and a power supply control method.SOLUTION: A power supply device comprises: a solar cell; a voltage detecting unit which detects a voltage of the solar cell; a switching unit which compares the voltage detected by the voltage detecting unit with a voltage threshold value and switches a set voltage which is associated with a prescribed ratio of an open voltage of the solar cell on the basis of the comparison results; a control unit which sets the set voltage to a maximum power point voltage and stores power in a storage battery by performing a maximum power point follow-up control; and a storage battery in which generated power of the solar cell is stored by control of the control unit.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power supply device and a power supply control method.

  In recent years, attention has been focused on energy harvesting that stores energy obtained from the environment and operates equipment. Although the electric power obtained in such environmental power generation greatly depends on the environment, the electric power generated is weak on the order of μW to mA. For this reason, it is necessary to supply power to the device to be operated as efficiently as possible. Therefore, in general, a power supply circuit design with little loss is required, such as selecting an IC (integrated circuit) with low self-consumption.

In equipment that supplies power generated by solar cells to storage batteries and loads, the generated power is supplied directly to the storage batteries and loads, or power is supplied to the storage batteries and loads via the charge control circuit with a circuit configuration that has a power conversion function. Method is used.
For example, in Patent Document 1, a DC / DC converter (direct current voltage-direct current voltage converter) is stopped at low illuminance, and the generated power is supplied to a load without conversion, and at high illuminance, DC / DC It is disclosed that control is performed so that the output power of the solar cell is maximized by turning on the converter.

Japanese Patent Laid-Open No. 11-46457

  However, in the technique described in Patent Document 1, when the illuminance is low, the output voltage of the solar cell also decreases. Therefore, in the case where the output of the solar cell falls below the voltage of the storage battery, it may fall into a state where it cannot be stored. there were. Further, in the technique described in Patent Document 1, since the voltage value fluctuates because the DC / DC converter is not used at the bottom illuminance, the storage battery cannot be efficiently stored.

  The present invention has been made in view of the above problems, and provides a power supply device and a power supply control method capable of more efficiently using solar energy over a wide range from a low illuminance region to a high illuminance region. The purpose is to provide.

  In order to achieve the above object, a power supply device (1) according to an aspect of the present invention includes a solar cell (10), a voltage detection unit (20) that detects the voltage of the solar cell, and the voltage detection unit The switching unit (switching unit) that compares the set voltage with the voltage threshold (Ref1) and switches a set voltage (voltage of the setting terminal SET) that is a predetermined ratio of the open-circuit voltage of the solar cell based on the comparison result 30, the comparison unit 31, the switch 40, the resistor R1, the resistor R2, and the resistor R3), and a control for storing the storage battery (60) by setting the set voltage to the maximum power point voltage and performing the maximum power point tracking control. Unit (DC / DC converter 50) and a storage battery (60) in which the generated power of the solar cell is stored by the control of the control unit.

Moreover, in the power supply device according to an aspect of the present invention, the switching unit acquires the voltage of the solar cell when the control unit does not open the connection between the solar cell and the control unit,
At the measurement timing, the control unit opens the connection between the solar cell and itself and measures the open voltage, and performs the maximum power point tracking control based on the measured open voltage and the set voltage. You may do it.

  Further, in the power supply device according to one aspect of the present invention, the switching unit divides the voltage value of the solar cell by switching connection of a plurality of resistors, whereby the first set voltage and the second voltage are changed. The set voltage may be switched.

  In the power supply device according to one embodiment of the present invention, the first set voltage is a voltage value based on an open voltage at a first illuminance, and the second set voltage is greater than the first illuminance. The voltage value may be based on the open circuit voltage at the first illuminance with high illuminance.

  In the power supply device according to one embodiment of the present invention, the solar cell may be a dye-sensitized solar cell.

  In order to achieve the above object, a power supply control method according to an aspect of the present invention is a power supply control method in a power supply device that stores and operates generated power generated by a solar battery in a storage battery, and the voltage detection unit includes: The voltage detection procedure for detecting the voltage of the solar cell, and the switching unit compares the voltage detected by the voltage detection procedure with a voltage threshold, and based on the comparison result, the open circuit voltage of the solar cell A switching procedure for switching the set voltage at a predetermined ratio, and a control procedure in which the control unit sets the set voltage to the maximum power point voltage and stores the power in the storage battery by performing the maximum power point tracking control.

  ADVANTAGE OF THE INVENTION According to this invention, sunlight energy can be utilized more efficiently over the wide range from a low illumination intensity area to a high illumination intensity area.

It is a block diagram which shows the structural example of the power supply device which concerns on this embodiment. It is a figure which shows the state of the power supply device in the case of high illumination intensity which concerns on this embodiment. It is a figure for demonstrating the maximum power point of a solar cell. It is a block diagram of the structural example of the power supply device which concerns on a prior art. It is a figure which shows the example of a characteristic of the voltage versus current in a solar cell in case illumination intensity is 200lux. It is a figure which shows the example of a characteristic of the voltage versus current in a solar cell in case illumination intensity is 10,000lux. It is a figure which shows the example of a characteristic of the ratio of the illumination intensity versus MPPT in white LED light and pseudo-sunlight. It is a flowchart of the process which the power supply device which concerns on this embodiment performs.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram illustrating a configuration example of a power supply device 1 according to the present embodiment. The power supply device 1 supplies power to the load and operates the load.

  As shown in FIG. 1, the power supply device 1 includes a solar cell 10, a voltage detection unit 20, a switching unit 30 (switching unit), a switch 40 (switching unit), a DC / DC converter 50 (control unit), a storage battery 60, a resistance. R1 (switching unit), resistor R2 (switching unit), and resistor R3 (switching unit) are provided. The switching unit 30 includes a comparison unit 31 (switching unit).

The output side of the solar cell 10 is connected to the input terminal IN of the DC / DC converter 50 and one end of the resistor R1 through the voltage detection unit 20.
The voltage detection unit 20 has a detection voltage value output terminal connected to the input side of the switching unit 30.
The switching unit 30 has a switching output terminal connected to the control terminal CNT of the switch 40.
The switch 40 has a terminal a connected to one end of the resistor R3, and a terminal b connected to the other end of the resistor R1, one end of the resistor R2, and a setting terminal SET of the DC / DC converter 50.
The other end of the resistor R2 is grounded. The other end of the resistor R3 is grounded.
The output side of the storage battery 60 is connected to the storage battery connection terminal of the DC / DC converter 50.

  The solar cell 10 has a high illuminance intensity under outdoor sunlight (eg, 10 [lux]) from an environment where the illuminance intensity is low (eg, 10 [lux]) such as under a fluorescent lamp where sufficient power generation efficiency cannot be obtained with a general solar cell. For example, it is a dye-sensitized solar cell that can efficiently generate power up to (lux) environment.

  The voltage detection unit 20 detects the voltage value V <b> 1 output from the solar cell 10 and outputs the detected voltage value V <b> 1 to the switching unit 30.

  The switching unit 30 controls the switch 40 according to the result of the comparison unit 31 comparing the voltage value V1 detected by the voltage detection unit 20 and the threshold voltage Ref1. When the voltage value V1 is less than the threshold voltage Ref1, the switching unit 30 controls the switch 40 to be in an open state (off state). In this case, the illuminance is less than the predetermined illuminance. When the voltage value V1 detected by the voltage detection unit 20 is equal to or higher than the threshold voltage Ref1, the switching unit 30 controls the switch 40 to be in a closed state (on state). In this case, the illuminance is greater than or equal to a predetermined illuminance. The switching unit 30 compares the voltage value V1 detected by the voltage detection unit 20 and the threshold voltage Ref1 during a period in which the measurement signal output from the DC / DC converter 50 indicates that the solar cell 10 is not opened. The switch 40 may be controlled according to the result of the comparison made by 31.

The comparison unit 31 stores a predetermined threshold voltage Ref1 set in advance according to the illuminance. The comparison unit 31 compares the voltage value V1 detected by the voltage detection unit 20 with the threshold voltage Ref1. The threshold voltage Ref1 is a voltage value when the illuminance is, for example, 10,000 [lux]. As an example, if the voltage value at 100,000 [lux] is about 2.7 [V], the threshold voltage Ref1 is about 2.16 [V] (= 2.7 × 80%).
The switch 40 is switched between a closed state and an open state according to the control of the switching unit 30.

  The DC / DC converter 50 converts the DC voltage input from the solar cell 10 into a different DC voltage, and supplies the converted DC power to the load. The DC / DC converter 50 converts a DC voltage input from the solar battery 10 into a DC voltage, and stores the converted DC power in the storage battery 60. The DC / DC converter 50 opens the connection between the solar cell 10 and the DC / DC converter 50 for a short time (for example, 256 [ms]) at a predetermined measurement timing (for example, once every several tens of seconds). The open-circuit voltage of the battery 10 is measured, and control is performed by a maximum power point tracking control (MPPT) method, which will be described later, based on the measured open-circuit voltage and the voltage value (set voltage) of the setting terminal SET. The DC / DC converter 50 may output an open signal indicating the timing at which the open voltage of the solar cell 10 is measured to the switching unit 30. The open signal is, for example, an H (high) level during a battery open period, and an L (low) level during other periods.

  The storage battery 60 is, for example, a lithium ion capacitor having a capacity of 40 F (Farad). The storage battery 60 stores the electric power generated by the solar battery 10 under the control of the DC / DC converter 50.

Next, the case where the illuminance is low (low illuminance) will be described with reference to FIG.
The low illuminance is, for example, illuminance less than 10,000 [lux]. In this case, the voltage value V2 of the open circuit voltage of the solar cell 10 is less than the voltage threshold value Ref1. For this reason, the switching unit 30 controls the switch 40 to be in the open state.
Thereby, the voltage value of following Formula (1) into which the voltage of the solar cell 10 was divided | segmented by resistance R1 and resistance R2 is input into the setting terminal SET of the DC / DC converter 50.

Next, the case of high illuminance (high illuminance) will be described with reference to FIG.
FIG. 2 is a diagram illustrating a state of the power supply device 1 in the case of high illuminance according to the present embodiment.
The high illuminance is, for example, illuminance of 10,000 [lux] or more. In this case, the voltage value V2 of the open circuit voltage of the solar cell 10 is not less than the voltage threshold value Ref1. For this reason, the switching unit 30 controls the switch 40 to be in a closed state.
Thereby, the voltage value of following Formula (2) into which the voltage of the solar cell 10 was divided | segmented by resistance R1, resistance R2, and resistance R3 is input into the setting terminal SET of the DC / DC converter 50.

Here, the maximum power point for effectively using the power generated by the solar cell will be described.
FIG. 3 is a diagram for explaining the maximum power point of the solar cell. In FIG. 3, the horizontal axis represents the voltage of the solar cell, the left vertical axis represents current, and the right vertical axis represents power. Waveform g1 is a change in voltage versus current. Waveform g2 is a change in voltage versus power.
As shown in waveform g1, a current value when the voltage 0 is I1, a current value when the voltage value V _M is I1 smaller I2, the current value when the voltage value V _O is 0.
Further, as shown in waveform g2, 0 is the power value when the voltage 0 is the power value when the voltage value V _M is P1, the power value when the voltage value V _O is 0.
Voltage value V _O is the open voltage, the voltage value V _M, a voltage capable of generating the greatest power, i.e. the maximum power point voltage.
As will be described later, the characteristics shown in FIG. 3 change depending on the illuminance irradiated on the solar cell. For the same voltage, the current value increases as the illuminance increases. Further, the open circuit voltage increases to a predetermined value according to the magnitude of the illuminance.

Thus, in order to use the electric power generated by the solar cell to the maximum and effective, it is necessary to control the maximum power point voltage.
As a method for controlling the maximum power point voltage, for example, a maximum power point tracking control method using a hill climbing method or the like is known. Such an MPPT control method is used, for example, in a power conditioner of a solar power generation system. However, the configuration in which the MPPT method is frequently controlled is expensive, and the power consumed by the MPPT method is large. For this reason, in this embodiment, the open-circuit voltage is measured every predetermined time (for example, once every several tens of seconds), and simple MPPT control is performed according to the measured open-circuit voltage and the voltage of the setting terminal SET. I do.

Here, an operation example of the power supply device in the conventional power supply device will be described.
FIG. 4 is a block diagram of a configuration example of a power supply device 900 according to the related art.
As shown in FIG. 4, the power supply device 900 includes a solar cell 910, a DC / DC converter 950, a storage battery 960, a resistor R901, and a resistor R902.

The solar cell 910 is, for example, a general amorphous solar cell.
The DC / DC converter 950 stores the electric power generated by the solar cell 910 in the storage battery 960 according to the voltage value obtained by dividing the voltage value generated by the solar cell 910 by the resistor R901 and the resistor 902. The voltage is divided by the resistors 901 and 902 to about 80% of the open circuit voltage. The DC / DC converter 950 measures the open circuit voltage. Subsequently, the DC / DC converter 950 controls the measured open circuit voltage so as to be a voltage set by dividing the resistance 901 and the resistor 902, that is, 80% of the open circuit voltage. The reason for setting to 80% is that the maximum power point voltage is about 80% of the open circuit voltage.

That is, in the conventional power supply device 900, the percentage of the open circuit voltage to be controlled is determined by the resistance ratio of the external resistors R901 and R902 of the DC / DC converter 950. Amorphous solar cells are generally suitable for use under electric light, but when used in an environment exceeding 1000 [lux], for example, the amorphous solar cells deteriorate light. For this reason, in the conventional power supply device 900, the range of the illumination intensity irradiated to the solar cell 910 was limited.
As described above, when the illuminance applied to the solar cell 910 used in the power supply device 900 is substantially constant, the solar cell 910 can be operated by setting about 80% of the open-circuit voltage as the maximum power point voltage as in the prior art. The electric power generated by the battery 910 could be used efficiently to some extent.

However, when the power supply device 1 is used for energy harvesting (environmental power generation), operation in a wide illuminance range from low illuminance to high illuminance is desired.
For this reason, in the power supply device 1 of this embodiment, the dye-sensitized solar cell which can respond also to wide illumination intensity is used for the solar cell 10. FIG. In order to effectively use the electric power generated by the dye-sensitized solar cell, it is important to set the maximum power point voltage. However, the maximum power point voltage varies depending on the illuminance as shown in FIGS.

FIG. 5 is a diagram illustrating an example of voltage versus current characteristics in the solar cell 10 when the illuminance is 200 [lux]. FIG. 6 is a diagram illustrating a voltage-current characteristic example in the solar cell 10 when the illuminance is 10,000 [lux]. 5 and 6, the horizontal axis represents voltage, and the vertical axis represents current.
As shown in FIG. 5, when the illuminance is 200 [lux], the open circuit voltage is about 2200 [mV], and when the voltage is 0 V, the current is about 135 [μA]. The maximum power point voltage when the illuminance is 200 [lux] is about 1760 [mV] (= 2200 × 80%).
As shown in FIG. 6, when the illuminance is 10,000 [lux], the open circuit voltage is about 2700 [mV], and when the voltage is 0 V, the current is about 9400 [μA]. The maximum power point voltage when the illuminance is 10,000 [lux] is about 2160 [mV] (= 2700 × 80%).

As shown in FIGS. 5 and 6, the maximum power point voltage differs depending on the illuminance.
For this reason, in the case of the conventional power supply device shown in FIG. 4, when the values of the resistors R901 and R902 are set in accordance with the high illuminance, the operation cannot be performed at the optimum maximum power point voltage at the low illuminance. Conversely, when the values of the resistors R901 and R902 are set in accordance with the low illuminance, the operation cannot be performed with the optimum maximum power point voltage at the high illuminance. In the case of a conventional power supply device, depending on the environment in which it is used, the change in illuminance is small and the range of illuminance that can be generated by the solar cell is narrow. Therefore, as shown in FIG. Even if each value of R902 is set, there is a case where it can be operated.

However, energy harvesting requires a system that can generate and operate effectively over a wide range of illuminance from illumination to sunlight.
In response to such a request, the power supply device 1 of the present embodiment uses a dye-sensitized solar cell for the solar cell 10 that can effectively generate power with a wide range of illuminance from illumination light to sunlight.
And in this embodiment, according to the detected voltage of the solar cell 10, the first set voltage set to be the maximum power point voltage at the time of low illuminance, and the maximum power point voltage at the time of high illuminance The second set voltage set as described above is switched by the switch 40. That is, as shown in FIG. 1, the voltage of the formula (1) in which the voltage V1 of the solar cell 10 is divided by the resistors R1 and R2 is the first set voltage for low illuminance (for example, 1760 [mV]). ). Further, as shown in FIG. 2, the voltage of the formula (2) in which the voltage V1 of the solar cell 10 is divided by the resistor R1, the resistor R2, and the resistor R3 is the second set voltage (for example, 2160) for high illuminance. [MV]).

Next, a characteristic example of the ratio of illuminance to MPPT in white LED (light emitting diode) light and pseudo-sunlight will be described.
FIG. 7 is a diagram illustrating a characteristic example of the ratio of illuminance versus MPPT in white LED (light emitting diode) light and pseudo-sunlight. The ratio of MPPT is the ratio of the maximum power point voltage to the open circuit voltage, where 1 is 100% and 0.8 is 90%. In FIG. 7, the horizontal axis indicates illuminance, and the vertical axis indicates the MPPT ratio (1 is 100%). Moreover, a rhombus is white LED light and a square is pseudo sunlight. In addition, the open circuit voltage of each plot point changes with illumination intensity. The maximum power point voltage varies depending on the illuminance. Therefore, the values of the MPPT ratio on the vertical axis are values calculated by measuring the maximum power point voltage and the maximum voltage for each illuminance on the horizontal axis and dividing the maximum power point voltage by the maximum voltage.

As shown in FIG. 7, the ratio of MPPT is about 0.8 (80%) below about 4000 [lux] and 0.65 (65%) above about 10,000 [lux].
As shown in FIG. 7, when the power supply device 1 is used in an environment other than a constant illuminance environment, the ratio of illuminance to MPPT is converted according to the illuminance. In particular, when one solar cell 10 is used in a wide illuminance range from low illuminance (several hundred [lux]) to high illuminance (tens of thousands [lux]), the MPPT ratio setting is changed according to the illuminance. Can be used efficiently. For this reason, in this embodiment, the voltage of the setting terminal SET is switched according to the illuminance.

For example, the designer of the power supply device 1 measures open voltages of about 200 [lux] and about 10,000 [lux] at the time of design. The designer of the power supply device 1 measures the maximum power point voltage of low illuminance, for example, about 200 [lux], and sets the measured maximum power point voltage to the first set voltage. The designer of the power supply device 1 sets the resistance value at which the divided voltage of the open voltage of the solar cell by the resistor R1 and the resistor R2 becomes the first set voltage. For example, the resistance value is set to 80% of the measured voltage value V1 of the solar cell.
The designer of the power supply device 1 measures the maximum power point voltage of high illuminance, for example, about 10,000 [lux], and sets the measured maximum power point voltage as the second set voltage. The designer of the power supply device 1 sets the resistance value at which the divided voltage of the open voltage of the solar cell by the resistors R1, R2, and R3 becomes the second set voltage. For example, the resistance value is set to 65% of the measured voltage value V1 of the solar cell.

Next, an example of a processing procedure performed by the power supply device 1 will be described.
FIG. 8 is a flowchart of processing performed by the power supply device 1 according to the present embodiment.
(Step S1) The switching unit 30 acquires the voltage value V1 of the solar cell 10 detected by the voltage detection unit 20 when the measurement signal output from the DC / DC converter 50 indicates that the solar cell is not opened.
(Step S2) The comparison unit 31 compares the acquired voltage value V1 with the voltage threshold value Ref1.

  (Step S <b> 3) The switching unit 30 determines whether or not the voltage value V <b> 1 is equal to or higher than the voltage threshold value Ref <b> 1 according to the comparison result of the comparison unit 31. When the switching unit 30 determines that the voltage value V1 is greater than or equal to the voltage threshold value Ref1 (step S3; YES), the switching unit 30 proceeds to the process of step S4 and determines that the voltage value V1 is less than the voltage threshold value Ref1 (step S3). NO), the process proceeds to step S5.

(Step S4) The switching unit 30 controls the switch 40 so as to be in the on state. That is, the switching unit 30 switches the switch 40 to the second set voltage for high illuminance. After processing, switching part 30 advances to processing of Step S6.
(Step S5) The switching unit 30 controls the switch 40 so as to be in an off state. That is, the switching unit 30 switches the switch 40 to the first set voltage for low illuminance. After processing, switching part 30 advances to processing of Step S6.

  (Step S6) At the measurement timing, the DC / DC converter 50 opens the connection between the solar cell 10 and the DC / DC converter 50 for a short time (for example, 256 [ms]), and measures the open voltage of the solar cell 10. To do. Subsequently, the DC / DC converter 50 performs MPPT control based on the measured open circuit voltage and the voltage of the setting terminal SET. After the process, the DC / DC converter 50 returns to the process of step S1.

  The power supply device 1 repeats the processing of step S1 to step S6 every predetermined time. The predetermined time may be set according to the power consumption of the load to which the power supply device 1 supplies power. The predetermined time may be set according to the environment (illuminance, illuminance change cycle) in which the power supply device 1 is installed. For example, in an environment such as an office where the time when the illuminance change is expected in the environment to be used is known in advance, a voltage value is acquired every minute, for example, during the time zone when the illuminance is expected to change. For example, a voltage value may be acquired every hour in a time body in which no change is predicted. The predetermined time for performing the process may be a predetermined time.

  Moreover, although this embodiment demonstrated the example which divides the voltage of the solar cell 10 by resistance, it is not restricted to this. For example, a first setting voltage for low illuminance and a second setting voltage for high illuminance may be generated using a Zener diode or the like.

  In this embodiment, an example in which the first setting voltage for low illuminance and the second setting voltage for high illuminance are switched has been described. However, for example, three or more setting voltages (for example, low illuminance) , Medium illuminance, high illuminance). In this case, two voltage thresholds are set, and the switching unit 30 switches to the first set voltage when it is less than the first voltage threshold, and when it is greater than or equal to the first voltage threshold and less than the second voltage threshold. It is possible to switch to the second set voltage and switch to the third set voltage when the voltage is equal to or higher than the second voltage threshold. For example, in FIG. 7, a voltage threshold value may be set and switched for each section (diamond or square) plotted from 0 to 20,000 [lux].

  In addition, although this embodiment demonstrated the example which uses light as an example of energy harvesting and uses a solar cell as an example of a power generation element, it is not restricted to this. The solar cell may be another power generation element (for example, vibration, geothermal heat, etc.) whose maximum power point voltage varies depending on the environment.

As described above, according to the present embodiment, a wide range from the low illuminance region to the high illuminance region can be obtained by switching the setting voltage for setting the maximum power point voltage based on the voltage value of the solar cell according to the illuminance. The solar energy can be used more efficiently.
Thus, by switching the set voltage in accordance with the illuminance, the efficiency is improved by about twice in the best case as compared with the case where the set value is not switched.

  A program for realizing all or part of the functions of the switching unit 30 and the DC / DC converter 50 in the present invention is recorded on a computer-readable recording medium, and the program recorded on the recording medium is stored in a computer system. You may perform the process which the switching part 30 and the DC / DC converter 50 perform by reading and performing. Here, the “computer system” includes an OS and hardware such as peripheral devices. The “computer system” includes a WWW system having a homepage providing environment (or display environment). The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Further, the “computer-readable recording medium” refers to a volatile memory (RAM) in a computer system that becomes a server or a client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. In addition, those holding programs for a certain period of time are also included.

  The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, what is called a difference file (difference program) may be sufficient.

DESCRIPTION OF SYMBOLS 1 ... Power supply device, 10 ... Solar cell, 20 ... Voltage detection part, 30 ... Switching part, 31 ... Comparison part, 40 ... Switch, 50 ... DC / DC converter, 60 ... Storage battery, R1, R2, R3 ... Resistance, V1 ... Voltage value of detected solar cell, V2 ... Open voltage of solar cell

Claims (6)

Solar cells,
A voltage detector for detecting the voltage of the solar cell;
A switching unit that compares the voltage detected by the voltage detection unit with a voltage threshold and switches a set voltage that is a predetermined ratio of the open-circuit voltage of the solar cell based on the comparison result;
A control unit configured to store in the storage battery by setting the set voltage to a maximum power point voltage and performing maximum power point tracking control;
A storage battery in which the generated power of the solar battery is stored by the control of the control unit;
A power supply device comprising: The switching unit acquires the voltage of the solar cell when the control unit does not open the connection between the solar cell and the control unit,
At the measurement timing, the control unit opens the connection between the solar cell and itself and measures the open voltage, and performs the maximum power point tracking control based on the measured open voltage and the set voltage. The power supply device according to claim 1. The switching unit is
3. The power supply device according to claim 1, wherein the voltage value of the solar cell is switched by dividing a connection of a plurality of resistors to switch between the first set voltage and the second set voltage. 4. . The first set voltage is a voltage value based on an open voltage at the first illuminance,
The power supply device according to claim 3, wherein the second set voltage is a voltage value based on an open-circuit voltage when the first illuminance is higher than the first illuminance.   The power supply device according to any one of claims 1 to 4, wherein the solar cell is a dye-sensitized solar cell. A power supply control method in a power supply device that stores and operates generated power generated by a solar battery in a storage battery,
A voltage detection unit for detecting a voltage of the solar cell;
The switching unit compares the voltage detected by the voltage detection procedure with a voltage threshold value, and based on the comparison result, a switching procedure for switching a set voltage that is a predetermined ratio of the open-circuit voltage of the solar cell;
A control unit sets the set voltage to the maximum power point voltage and stores the power in the storage battery by performing maximum power point tracking control; and
Power supply control method including.

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