JPH0754768Y2 - Sun tracking sensor - Google Patents

Description

[Detailed Description of the Invention] <Industrial application field> The present invention is provided in a device for automatically tracking the sun, such as a solar tracking solar collector and a solar power generation device, and detects the direction of the sun. Regarding

<Prior art> In order to always match the direction of the sun and the direction of the sun that automatically tracks the sun, such as a solar tracking type solar collector and solar power generation device, these devices are equipped with a sun tracking system that detects the direction of the sun. A sensor is provided.

Then, as the sun tracking sensor, one having a photoconductive sensor or a sunshine meter disposed on both sides of the partition plate has been devised. That is, when the surface including the partition plate does not match the direction of the sun, the partition plate blocks the sunlight and the sunlight does not enter the photoconductive sensor or the sunshine meter on either side of the partition plate. The resistance value of the photoconductive sensor or the generated voltage of the sunshine meter changes. This is utilized to detect the direction of the sun.

<Problems to be solved by the invention> The photoconductive sensor has a characteristic that temperature depends on temperature and a dark current flows.Therefore, when a temperature difference occurs between the elements on both sides of the partition plate, the temperature changes greatly. Has different characteristics. Therefore, the sun tracking sensor using the photoconductive sensor cannot reliably detect the direction of the sun. Further, if exposed to sunlight for a long time, the element performance is deteriorated and the life is shortened. Further, the photoconductive sensor requires a constant voltage power source in order to detect a change in resistance value by applying a predetermined voltage from the outside.

The sunshine meter has stable characteristics against temperature changes,
It has low light detection sensitivity, large shape, and is expensive. Therefore, the sun tracking sensor using the sunshine meter becomes large and expensive.

<Means for Solving the Problems> Therefore, the present invention was made to solve the above-mentioned problems, and it is possible to provide a small and inexpensive solar tracking sensor that can be installed outdoors for reliable detection. It is intended to be provided.

That is, a hemispherical cup provided inside a casing having an opening in the upper part, the opening surface of which is directed upward, and the inner surface of the hemispherical cup is divided into left and right parts, and a light reflecting portion formed on one of the inner surfaces and the other. A light-absorbing portion formed on the inner surface of the hemispherical cup, a light-collecting portion provided substantially at the center of the opening surface of the hemispherical cup, a light-shielding plate that seals the opening of the casing excluding the light-collecting portion, and an inner surface of the light-shielding plate A plurality of light receivers, each of which is composed of a light receiving element provided on the side and above the light reflecting portion,
Among the light receivers arranged in parallel, adjacent light receivers are
It is characterized in that the respective light reflecting portions are arranged facing each other or in the back.

<Operation> The output signal of each light receiving element changes depending on the direction of the sun tracking sensor with respect to the direction of the sun.

That is, since the adjacent light receivers have their light reflectors facing each other or arranged back to back, when the direction of the sun with respect to the sun tracking sensor changes, a deviation occurs in the traveling direction of the light transmitted through each light collector. The amount of light incident on one of the light reflection parts,
There is a difference between the amount of light incident on the other light reflecting portion. Therefore, there is a difference in the amount of light incident on both light receiving elements above the light reflecting portion. Therefore, a difference occurs in the output signal of each light receiving element, and the direction of the sun is detected by comparing these output signals.

Further, the light receiving element is provided inside the light shielding plate and the casing is sealed, so that the light receiving element is protected from rain, dust and the like.

<Embodiment> An embodiment of the present invention will be described with reference to the drawings.

The sun tracking sensor 1 shown in FIG. 1 comprises, for example, two light receivers 2 (2a, 2b) arranged side by side.

In the light receiver 2, a hemispherical cup 4 is provided inside a casing 3 having an opening at the top, with its opening surface 7 facing upward.

The inner surface of the sphere of the hemisphere cup 4 is divided into left and right parts, one of which is formed as a light reflecting portion 5 and the other of which is formed as a light absorbing portion 6. The light reflecting portion 5 is formed by applying white paint that reflects sunlight. Alternatively, it may be formed on a mirror surface where sunlight is reflected. The light absorbing portion 6 is formed by applying a black paint that absorbs sunlight.

The open surface 7 of the hemispherical cup is the open end 8 of the casing 3.
Is roughly matched with.

Then, the casing 3 is provided with a light condensing portion 10 substantially at the center of the opening surface 7 of the hemispherical cup without impairing the sealed state of the casing 3.

That is, the light shielding plate 9 closes the opening of the casing 3 except for the light converging portion 10.

The condensing unit 10 uses a fish-eye lens that emits vertically incident sunlight toward the front surface of the hemispherical cup 4.

Further, on the inner surface side of the light shielding plate 9 and above the light reflecting portion 5, a light receiving element is provided at a position where the reflected sunlight is collected.
11 (11a, 11b) are attached.

As the light receiving element 11, a silicon solar cell of a photovoltaic sensor, which has a small dark current and has little deterioration with time even if it is irradiated with sunlight for a long time, is used. Alternatively, a silicon photodiode can be used. The photovoltaic sensor has a feature that it does not require a constant voltage power source in order to detect an electromotive force generated by light irradiation.

The two adjacent light receivers 2a and 2b are arranged side by side with the light reflecting portion 5 (5a) of the light receiver 2a and the light reflecting portion 5 (5b) of the light receiver 2b facing back as shown in the figure. Has been done. In this case, both light absorbing parts 6 and 6 are in a state where their inner (spherical) surfaces face each other.

On the other hand, contrary to the example shown in the figure, if the two light reflecting portions 5 (5a) and 5 (5b) are arranged in parallel so as to face each other, the both light absorbing portions 6 and 6 will be in the state of facing back. It is possible in any of the juxtaposed states.

Next, the sun tracking sensor 1 that changes depending on the direction of the sun
The output signals of the two adjacent light receivers arranged side by side with both reflecting portions facing back will be described with reference to FIGS. 2 to 4.

Each of the light receiving elements 11a and 11b has a negative electrode and a negative electrode connected to each other,
The potentials Ea and Ed of both positive electrodes are compared as output signals of the light receiving elements 11a and 11b.

First, as shown in FIG. 2, when the sunlight L-1 is vertically incident on the sun tracking sensor 1, each light reflecting portion 5
The amount of light incident on and reflected by a and 5b is equal,
The amounts of light incident on a and 11b are also equal. Therefore, the light receiving element 1
The potential Ea of 1a and the potential Eb of the light receiving element 11b become equal. Therefore, the output signal becomes Ea−Eb = 0, and the potential difference between the two becomes zero.

Next, as shown in FIG. 3, when the sunlight L-2 is incident on the sun tracking sensor 1 while being inclined to the left, the light reflecting portion
Since the amount of light that is incident on and reflected by the light reflecting portion 5a is greater than that of 5b, the amount of incident light on the light receiving element 11a is greater than the amount of incident light on the light receiving element 11b. Therefore, the potential Ea of the light receiving element 11a becomes higher than the potential Eb of the light receiving element 11b. Therefore, the output signal is E
It becomes a-Eb> 0 and shows a positive potential difference.

Further, as shown in FIG. 4, when the sunlight L-3 is incident on the sun tracking sensor 1 while being inclined to the right, the amount of incident light from the light reflecting portion 5a to the light reflecting portion 5b is reversed, contrary to the above. Grows.
Therefore, the potential Ea of the light receiving element 11a becomes smaller than the potential Eb of the light receiving element 11b. Therefore, the output signal becomes Ea-Eb <0, which shows a negative potential difference.

Therefore, the direction of the sun with respect to the direction of the sun tracking sensor is detected by comparing and calculating the output signals of the light receiving elements 11a and 11b. Since the sun tracking sensor 1 has a closed structure, it can be installed outdoors. Moreover, since the photo-electric sensor that generates less dark current is used for the light receiving element 11, the direction of the sun can be reliably detected even outdoors where the temperature changes greatly. Further, each light receiving element 11 is connected to a heat conduction plate to make the temperature of each light receiving element 11 equal,
When the hemispherical cups 4 are communicated with each other by the air passage so that the temperatures inside the hemispherical cups 4 are equalized, the detection of the direction of the sun becomes more reliable.

Further, the sun tracking sensor 1 detects the direction of the sun. However, if the sun tracking sensor is installed in a state of facing the direction of change of the elevation angle of the sun, the elevation angle of the sun can also be detected.

If the sun tracking sensor for detecting the direction and the sun tracking sensor for detecting the elevation angle are used, the sun can be tracked regardless of the season or time.

<Advantages of the Invention> As described above, according to the present invention, the sun tracking sensor can be provided by installing it in the direction of movement of the sun, and a small and highly durable sun tracking sensor can be provided.

[Brief description of drawings]

FIG. 1 is a vertical sectional view for explaining an embodiment of the present invention, and FIGS. 2 to 4 are optical path diagrams for explaining sunlight incident on a hemispherical cup. 1 ... Sun tracking sensor, 2 (2a, 2b) ... Photo receiver, 3 ... Casing, 4 ... Hemispherical cup, 5 (5a, 5b) ... Light reflecting part, 6 ... Light absorbing part,
7 ... Aperture surface, 9 ... Shading plate, 10 ... Light condensing part, 11 (11a, 11b) ... Light receiving element.

Claims (1)

[Scope of utility model registration request] 1. A hemispherical cup provided inside a casing having an opening at an upper part, and an opening surface facing upward, and an inner surface of the hemispherical cup, which is divided into left and right parts, and a light reflection formed on one of the inner surfaces. And a light absorbing part formed on the inner surface of the other part, a light collecting part provided substantially in the center of the opening surface of the hemispherical cup, a light shielding plate that seals the opening of the casing excluding the light collecting part, and the light blocking A plurality of light receivers each comprising a light receiving element provided on the inner surface side of the plate and above the light reflecting portion are arranged in parallel, and among the light receivers arranged in parallel, adjacent light receivers are mutually adjacent. ,
A sun tracking sensor, characterized in that the respective light reflecting parts are arranged facing each other or in the back.