JPH0233525B2 - KANKISOCHI - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a ventilation device powered by solar cells, and is particularly designed to efficiently supply the generated output to a motor. .

[Conventional technology] Conventionally, when a car is parked in the hot sun for a long time,
The radiation from the solar cells causes the interior of the vehicle to reach an extremely high temperature, which not only causes great discomfort to the driver and passengers when reboarding the vehicle, but also increases the cooling load on the air conditioner. In response to this problem, the inventors of the present invention have previously filed a patent application
In No. 53915 (Japanese Unexamined Patent Publication No. 53-140731), we proposed a ventilation system for automobiles using solar cells. This prior invention ventilates the interior of the vehicle by driving a fan using the output electrical energy generated by the solar cells installed on the vehicle body when the vehicle is parked, thereby preventing the temperature from rising. The stronger the power, the greater the output electrical energy, that is, the amount of power generated, and the rotation speed of the fan increases accordingly, making it possible to increase the amount of ventilation air.Special control is required to adapt this rotation speed to changes in the weather. This has the advantage that ventilation capacity can be automatically controlled according to sunlight intensity without requiring any equipment.

[Problems to be Solved by the Invention] However, on the other hand, due to the relationship between the load current characteristics with respect to the fan voltage and the output current characteristics with respect to the output voltage of the solar cell, it is difficult to always operate the solar cell optimally regardless of the strength of solar radiation. It cannot be used under certain conditions. To explain this with Figure 1, first, when solar radiation is strong, the series-connected solar cells exhibit a V-I characteristic as shown in B, and the output power increases accordingly.
It exhibits characteristics similar to B′. As an example, when a fan having a VI characteristic such as a load current of A is used, the operating point is the intersection a of A and B, and the point a' is the maximum output point in that case. However, when the solar radiation becomes weak, the solar cell exhibits characteristics like C and C', the operating point becomes the intersection point b of A and C, and the output power becomes point b', which deviates from the maximum output point. It ends up. As described above, even if the device is adapted to operate at the optimal operating point when solar radiation is strong, it will deviate from the optimal operating point when solar radiation becomes weak. Conversely, even if the optimal operating point is achieved when solar radiation is weak, if solar radiation becomes strong, the optimal operating point will deviate. In either case, it is difficult to always operate the fan in an optimal state. Further, for example, for automobiles, a particular problem is how to install solar cells. In general, one of the difficulties when installing solar cells in a car with this type of device is that the direction of the car when parked does not change from moment to moment with respect to the direction of the sun, so it cannot be used in all cases. The optimal location for installing solar cells cannot be determined unambiguously, and furthermore, there is no easy method for installing solar cells. For example, as shown in FIGS. 2 and 3, solar cells SC _A and SC _B are connected to the front board 10, respectively.
Considering the case where the solar cells SC A and SC B are installed separately on the upper and rear boards 11, if the sun 200B is located directly above the car, the sunlight 210B will be incident on both the solar cells SC _A and SC _B. , when the sun is at a tilt of 200A or 200C, the solar rays 210A and 210C are SC A or SC _A or 210C, respectively.
Only SC _B will be incident. In such a case,
Solar cells SC _A and SC _B are connected in series, and a fan 20
When trying to drive SC _A or SC _B , the internal resistance of the solar cell that does not receive sunlight increases (current does not flow), and the solar cell that receives sunlight well increases its internal resistance. There is a problem in that the operating voltage of the device decreases, making it impossible to output effectively as a whole. This problem can be solved to some extent by installing the solar cell in a location that will not be in the shadow of the car, such as on the roof, regardless of the direction of the sun. However, even in this case, the following problem occurs. In other words, if a part of the solar cell is attached to an object other than the automobile,
For example, it may be in the shadow of leaves or buildings, so in such cases, it becomes difficult to extract effective output as in the case described above. In order to solve the above problem, the following ideas can be considered. In other words, the solar cell is divided into multiple parts and used in parallel with the load. According to this method, even if a part of the solar cell is in the shade, there is little effect on the load. However, the problem with this method is that the maximum voltage is small.
Another problem is that a large number of solar cells must be installed in anticipation of shade.

The present invention has been made in view of the above-mentioned problems, and is a solar radiation system that can supply optimal power to the motor of a ventilation system, regardless of the strength of solar radiation, its temporal changes, and fluctuations. It is an object of the present invention to provide a ventilation device configured to be powered by a photovoltaic device.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes at least two or more solar power generation means that convert outdoor light into electric power, and a system that is supplied with electric power from the solar power generation means. , a motor that drives a fan that ventilates indoor and outdoor spaces; a switching device that switches the connection of the solar power generation means to the motor to a series connection or a parallel connection; control means for controlling the switching means and switching the connection of the solar power generation means to a series connection or a parallel connection so that the solar power generation means generates a maximum output near the operating point of the motor; Use proper ventilation.

[Operations and Effects] According to the configuration of the present invention described above, the intensity of sunlight incident on the solar power generation means fluctuates, and the operating point of the fan of the ventilation device to which power is supplied from the solar power generation means fluctuates. When the operating point moves away from the maximum output point of the solar power generation means, the maximum output point of the solar power generation means can be adjusted by switching between series connection and parallel connection of the solar power generation means. It can be moved to closely follow the fluctuations in the operating point.

Therefore, it is possible to efficiently supply the power generated by the solar power generation means to the motor with a simple configuration, and to obtain a ventilation system that can efficiently utilize the output of the solar power generation means regardless of fluctuations in solar radiation. Can be done.

[Example] Hereinafter, the present invention will be explained with reference to Examples shown in the drawings.

First, a first embodiment will be described based on FIGS. 4 and 5. FIG. 4 shows the rear half of the vehicle body 1, in which solar cells SC _A and SC _B are fitted into a back visor 3 attached to the upper part of the rear window 2. Furthermore, a photodiode PD is attached to the center of the back visor, which is the position of the average solar radiation incident on the two solar cells SC _A and SC _B , which generates a current according to the light intensity of sunlight. Also,
A fan 20 (not shown) is attached to the rear floor of the vehicle body, which sucks cold outside air under the vehicle body as shown by arrow A and discharges it into the passenger compartment as shown by arrow B. The outside air A introduced into the vehicle interior becomes an airflow B, removes heat from the vehicle interior, and is discharged to the outside of the vehicle from an opening (for example, a front ventilator) not shown. Each of the solar cells SC _A and SC _B has a structure in which a large number of solar cell elements are connected in series inside a transparent acrylic container, as shown in FIG. 3, for example.

Figure 5 shows a solar cell that forms the main part of the present invention.
This figure shows an example of a means for switching between a series connection and a parallel connection of SC _A and SC _B. A load resistor R _L is connected in series to the photodiode PD.
It converts the generated current into a voltage signal.

COMP is a comparator that compares and outputs the voltage generated across the load resistor R _L and the reference voltage determined by the resistance ratio of the reference resistors R ₁ and R ₂ and the voltage of the constant voltage power supply V _cc . . The output of COMP is
When the solar radiation is strong, it becomes "0" and when it is weak, it becomes "1", and accordingly, the transistor Tr is made conductive and the relay coil 5 is energized. There are three contacts SW _A , SW _B , and SW _C driven by the relay coil 5, which switch the connection of the output terminals of the solar cells SC _A and SC _B. Furthermore, 4 is a drive motor for the fan 20.

The operation of the above circuit will be explained below with reference to FIGS. 1 and 5. In Figure 5, when solar radiation is strong,
Photodiode PD generates a large current and turns transistor Tr off. In this case, the contacts SW _A and SW _B are in an open state, the contact SW _C is in a closed state, and the solar cells SC _A and SC _B are connected in series. At this time, the solar cell exhibits the characteristics of B and B' in Figure 1, the current is at point a, and the output power is at the maximum output point.
It becomes point a′. Next, when solar radiation is weak, the photodiode PD generates only a small current, and the transistor
The Tr becomes conductive. Therefore, the contacts SW _A and SW _B
is in the closed state, contact SW _C is in the open state,
Solar cells SC _A and SC _B are connected in parallel. At this time,
The solar cell exhibits the characteristics D and D' in FIG. 1, the current is at point c, which is the intersection of A and D, and the output power is at point c', which is the maximum output point. The output at point c′ is significantly larger than point b′, which is the output point of the series connection when solar radiation is weak. As described above, by switching solar cells to series connection or parallel connection according to the strength of solar radiation, the output of the solar cells can be effectively used for ventilation by the fan 20, which is an excellent effect. is obtained.

In this example, the solar cell is divided into two independent containers, but the solar cell elements arranged in the same container can be divided into two parts by means such as electrical wiring or vapor deposition. Naturally, the same effect can be obtained even if it is divided and used.

Furthermore, as the light intensity detection means, it is also possible to use a solar cell element instead of the photodiode PD, or a phototransistor may be used.

As mentioned above, by switching the solar cells divided into two into series connection or parallel connection according to the intensity of solar radiation, the solar cells can always be used at the optimal output point, and the maximum output can be achieved with the limited number of solar cells. It is possible to obtain a cooling effect in the vehicle interior.

A second embodiment of the present invention will be described based on FIGS. 2, 3, and 6. In FIG. 2, on the front board 10 and rear board 11 of the vehicle body 1, solar cells SC _A and SC _B having the structure shown in FIG.
Sun 200 using hinge 30 as a bending member
A, 200B, and 200C are attached so that the elevation angle can be adjusted freely. Further, an elevation angle fixing member 31 is attached to the solar cells S _A and S _B to fix the solar cells S _A and S _B at a manually set desired elevation angle. The solar cells SC _A and SC _B have a structure in which a large number of solar cell elements 32 are connected in series and housed inside a transparent acrylic container 33 . 32
a and 32b are the output terminals of the solar cells SC _A and SC _B on the + side and - side, respectively. In addition, in the acrylic container 33, like the solar cell element 32,
Photodiodes PD _A and PD _B serve as light intensity detection means
is housed therein, and generates a current signal from the output terminal 34 according to the intensity of sunlight. 20 is
Solar cells installed on floor 21 of the trunk room
This is a fan driven by SC _A and SC _B , and the intake side is equipped with a wire mesh 22 to prevent small stones from entering the vehicle while driving, and the discharge side is equipped with a wire mesh 22 to prevent small items in the trunk from falling outside the vehicle. Wire mesh 2 to prevent
3 is installed.

Figure 6 shows a solar cell that forms the main part of the present invention.
This figure shows an example of means for switching between a series connection and a parallel connection of SC _A and SC _B. Photodiodes PD _A and PD _B have load resistances RL _A and RL _B, respectively.
are connected in series and convert the generated current into a voltage signal. NOR is a NOR circuit that logically determines whether the outputs of COMP A and COMP B are "1" or "0", and when both of its inputs are "0", that is, the photodiodes PD _A ,
When both PD _B output more than the set value (insolation is strong), the output becomes "1", the transistor (Tr) becomes conductive, and the relay coil 5 is energized. SW _A , SW _B , driven by relay coil 5
There are three contacts SW _C , which switch the connection of the output terminals of the solar cells SC _A and SC _B.

The operation of the above circuit will be explained based on FIGS. 2, 3, 6, and 7. Case 1 in the table of Fig. 7 shows the case where the sun is at the position 200B shown in Fig. 2, and the solar cells SC _A ,
SC _B is both receiving strong solar radiation, and photodiodes PD _A and PD _B have large outputs. Therefore, the relay coil 5 is energized and the contacts SW _A ,
SW _B is in an open state, and contact SW _C is in a closed state. At this time, the solar cells SC _A and SC _B and the fan drive motor 4 are connected in series as shown in the table of FIG. At this time, the drive motor 4 of the fan 20 is supplied with a high voltage and a large current, so the drive motor 4 of the fan 20 rotates at a high speed, resulting in a large air volume and an increased cooling effect in the vehicle interior. 7th
Case 2 or 3 in the table of the figure indicates a case where either one of the solar cells is in the shade or the sunlight is significantly reduced, the relay coil 5 is in a non-energized state, and the contacts SW _A and SW _B are in the non-energized state. It becomes a closed state,
Contact SW _C becomes open. Therefore, as shown in the table of FIG. 7, the solar cells SC _A and SC _B are connected in parallel. At this time, the drive motor 4 of the fan 20 has
A medium voltage and a current determined by the intensity of solar radiation received by the solar cell are supplied, and the drive motor 4 of the fan 20 rotates at a medium speed to ventilate the inside and outside of the vehicle with a corresponding air volume. Case 4 in the table of FIG. 7 indicates a case where both solar cells SC _A and SC _AB are in the shade or the intensity of solar radiation is significantly reduced, and the relay coil 5 is in case 2 or 3. Similarly, it becomes de-energized, and as a result, SC _A and SC _B are connected in parallel. At this time as well, a medium voltage should be supplied to the drive motor 4 of the fan 20, but since the internal resistance of both solar cells increases, the current becomes extremely small, and the drive motor 4 of the fan 20
will rotate at a low speed. Therefore, at this time, ventilation is performed with a small amount of air, but as long as neither of the two solar cells receives solar radiation, the temperature inside the vehicle does not rise significantly, so no major inconvenience occurs.

Next, a third embodiment will be described below based on FIG. 8. FIG. 8 shows a third embodiment of the present invention, in which solar cells _SC'A and _SC'B are arranged side by side on a back visor 40. In this case, photodiodes PD' _A and PD' _B are arranged at the center positions of solar cells SC' _A and SC' _B , respectively, and 20' indicates a fan. The feature of the embodiment shown in FIG. 8 is that the solar cells SC' _A and SC' _B are arranged approximately horizontally on the back visor 40 so as not to be in the shadow of the car and not to be affected by the direction of the sun. Since it is installed, when one of the solar cells is parked and gets behind a leaf or a building, it will be detected reliably and the connection between both solar cells will be immediately switched from series connection to parallel connection, making it more effective. It is possible to obtain a cooling effect in the vehicle interior. Note that as the light intensity detection means, a solar cell element or a phototransistor may be used instead of the photodiode.

The effect of the third embodiment is that a means is provided to separately and reliably detect the solar radiation state or shaded state of each of the two solar cells, and to switch to series connection or parallel connection based on the detection result. Therefore, optimal ventilation can be achieved and an effective cooling effect can be obtained.

Next, regarding the fourth example, from FIG.
This will be explained below based on FIG. In the fourth embodiment shown in FIGS. 9 to 12, the terminal voltage of the drive motor 4 of the fan 20 driven by the output of the solar cell is controlled by the solar cell without installing a special photodiode as a light intensity detection means. This method takes advantage of the fact that the incident light intensity changes. 9 and 10 show an example of the installation of the solar cell of this embodiment, in which a P layer 301 and an N layer 302 are formed on the inner surface of the rear window 200 on the passenger compartment side by vacuum evaporation. A large number of amorphous solar cells (for details, please refer to Morikita Publishing, ``Solar Power Generation'', edited by Kiyoshi Takahashi et al.) are installed at intervals that do not significantly obstruct the driver's vision. , SC _A and aluminum connection electrode 303
Connect to SC _B in two groups, lead wires 100 and 101, and 102 and 103.
They were connected to form the electric circuit shown in FIG. 12. In addition, 301, 302,
303 has its surface coated with reinforced resin. Next, the principle of operation will be explained based on FIG. When the radiation intensity of sunlight is strong, the drive motor 4 of the fan 20 is connected in parallel with the solar cell, and as the radiation intensity gradually becomes stronger, the voltage increases as indicated by arrow a in the figure. When the radiation intensity reaches W ₁ , the solar cells switch to series connection, and as the radiation intensity decreases, the voltage drops along arrow b, and when the radiation intensity decreases to W ₂ , they switch to parallel connection, and as shown by arrow c.
The voltage drops along. In other words, the series connection and parallel connection are centered on the voltage V _REF at the intersection of the series connection curve and the parallel connection curve, with a hysteresis width V _H determined by the upper limit value V _N and the lower limit value V _N ′. Switch between the two depending on the radiation intensity of the sun's rays. By providing hysteresis in this way, when the range of change in solar radiation intensity is small, etc.
It is possible to prevent chattering during the switching operation between series connection and parallel connection of solar cells, and there is no need for a special sensor to detect the incident intensity of sunlight.

A supplementary explanation will be given below regarding FIG. 11.

(1) When solar cells are connected in parallel: A large amount of current can be supplied even when the radiation intensity of sunlight is low, and the voltage of the solar cells is less likely to drop, so parallel connection is better than series connection. drives the drive motor 4 of the fan 20 with a relatively high voltage, but as the radiation intensity increases, there is a limit to the voltage that can rise, so the voltage becomes saturated.

(2) When solar cells are connected in series: Contrary to case (1), as the radiation speed increases, not only can more current be supplied, but the voltage also increases. 4 can be driven, and therefore the air volume can be increased compared to parallel connection.

FIG. 12 shows the electric circuit of the fourth embodiment, which includes a voltage follower OP ₁ that generates a reference voltage set by resistors R _a and R _b and a constant voltage power supply V _cc , and V _REF The main part is a comparator OP ₂ having a capacitor C that provides a hysteresis width V _H determined by P _c and R _d and a time delay. One input of comparator OP ₂ is
The + terminal of the drive motor 4 of the fan 20, that is,
It is connected to the + terminal 100 of the solar cell SC _A.
Therefore, when the radiation intensity of sunlight is weak and the voltage generated by the solar cell is low, the transistor Tr is in a conductive state and the relay coil 5 is energized, thereby closing SW _A and SW _B , and SW _C is released.
Therefore, solar cells SC _A and SC _A are connected in parallel. After that, the radiation intensity of the sun's rays increases, +
When the voltage at terminal 100 increases, the transistor
The Tr changes from a conductive state to a non-conductive state, and the contacts SW _A , SW _B , which are driven by the relay coil 5
SW _C is in the state shown in Figure 12, and solar cell SC _A
and SC _B are connected in series.

In this example, the solar cell was divided into two parts, but it is naturally possible to divide the solar cell into four, six, or eight parts and connect them in combination, and the greater the number of divisions, the finer the detail. Control becomes possible.
Moreover, a control circuit such as a comparator can also be incorporated into the solar cell as an integrated circuit.

In the above embodiments, the case where the ventilation device of the present invention was adopted for automobiles was explained, but the present invention is not limited to automobiles, and can also be effectively used for other purposes, such as for ventilation of houses. It is possible.

[Brief explanation of drawings]

Figure 1 is a solar cell load characteristic diagram showing the relationship between the strength of solar radiation, the connection between two systems of solar cells, and the output current, output voltage, and output power of the solar cell obtained based on the connection. FIG. 2 is an explanatory diagram schematically showing the arrangement of the constituent elements of the device of the present invention, and FIG.
A perspective view showing the configuration of the solar cell used in the present invention, FIG. 4 is an explanatory view schematically showing the arrangement of the constituent elements of the device according to the first embodiment of the present invention, and FIG.
A circuit diagram showing an electric circuit of a first embodiment of the present invention,
FIG. 6 is a circuit diagram showing the electric circuit of the second embodiment of the present invention, and FIG. 7 shows the state of change in the connection of the solar cell of the second embodiment of the present invention under various solar radiation conditions. The explanatory diagram shown in FIG. 8 is the third embodiment of the present invention.
9 and 10 are explanatory diagrams schematically showing the arrangement of the constituent elements of the apparatus of the fourth embodiment, and FIG. 11 is an explanatory diagram schematically showing the arrangement of the constituent elements of the apparatus of the fourth embodiment. is a characteristic diagram showing the relationship between the radiation intensity of sunlight, the terminal voltage of the drive motor 4 of the fan 20, and the change in the connection of the solar cell in the fourth embodiment;
FIG. 2 is a circuit diagram showing an electric circuit according to a fourth embodiment of the present invention. Explanation of symbols, 1...Vehicle body, SC _A , SC _B ...Solar cell, PD _A , PD _B ...Photodiode, 20...
Juan.

Claims (1)

[Scope of Claims] 1. At least two or more solar power generation means that convert outdoor light into electric power; A motor that is supplied with electric power from the solar power generation means and drives a fan that ventilates indoor and outdoor spaces; a switching means for switching the connection of the solar power generation means to a series connection or a parallel connection; and controlling the switching means according to the intensity of incident light to the solar power generation means, so that the solar power generation means operates the motor. 1. A ventilation system comprising: a control means for switching the connection of the solar power generation means to a series connection or a parallel connection so as to generate a maximum output near a point. 2. The control means is configured to connect the solar power generation means in series as the intensity of the incident light increases, and to connect the solar power generation means in parallel as the intensity of the incident light decreases. The ventilation device according to claim 1, characterized in that: