JPH0157768B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic tracking device capable of broadly and accurately following the movement of a light source that can be clearly distinguished from other objects such as the sun or the moon.

In recent years, we have entered an era of energy conservation, and solar energy has been attracting attention as one of the next energy sources, and research and development is being actively conducted in various fields on its effective and effective use.

The present invention was made as part of this effort, and in particular, a lens system for concentrating solar energy is moved to follow the movement of the sun, so that solar energy can always be collected in the most efficient manner. However, it will be easily understood from the following description that the present invention is capable of tracking not only the movement of the sun but also the movement of the moon and other light-emitting or reflective objects.

FIG. 1 is a diagram for explaining the operating principle of the present invention. In the figure, 1 is a lens system for focusing sunlight SL, for example, a Fresnel lens. 2 is a light pipe, a photoelectric converter or a photothermal converter for collecting the solar energy focused by the lens system 1, e.g. The light is guided to a location where it can be used as is, as illumination light, or converted into electrical energy or thermal energy. 3
are the lens system 1, solar energy collecting means 2,
And photodetection means 4x ₁ , 4x ₁ ', 4y ₁ , which will be described later.
4y ₁ ', and the support frame 3 is normally controlled by a device not shown so as to follow the movement of the sun. As an example of such a sunlight tracking method, a method has conventionally been proposed in which a solar energy detection device is provided and the entire condensing device, that is, the support frame, follows the movement of the sun based on the output of this solar energy detection device. However, this method has the disadvantage that sunlight is blocked by clouds, etc., and once the tracking point is lost, subsequent tracking becomes extremely difficult. In order to avoid this drawback, a method has been considered in which the movement of the sun is predicted in advance and the entire condensing device follows the movement of the sun using a clock mechanism.
According to this method, it is unclear whether or not the solar energy collecting means accurately matches the focal position of the lens system 1, and in the worst case, a situation where no light can be collected may continue. It was hot.

In this regard, as shown in FIG. Pair of photodetecting elements 4x ₁ , 4
By providing x ₁ '; 4y ₁ and 4y ₁ ', the position of the sun in a wide area can be detected and the concentrator can be made to follow the direction of the sun. That is, FIGS. 2 and 3 are diagrams for explaining the operation of the automatic tracking device shown in FIG.
_The shaded area S in FIG. 2 is _a solar image in _the plane shown in _FIG . It is set up.

FIG. 3 is a diagram showing the relationship between the angle of incidence of sunlight on the plane of the lens system 1 and the focal position. When the angle is 0°, the solar image is formed on the solar energy collecting means 2. However, as the angle of incidence of sunlight on the lens system 1 shifts, its imaging (focal point) position also shifts.
When the angle is 30°, the image is formed at the A ₃₀ position, and when it is 60°, the image is formed at the A ₆₀ position. Therefore, in FIG. 3, when the photodetecting elements 4x ₁ and 4x ₁ ' are arranged at the positions shown, the photodetecting elements 4x ₁ are placed at an angle of approximately 0° to 30° to the right with respect to the lens system 1. Detects sunlight when the sun is within range,
At this time, since the photodetecting element 4x ₁ ' does not receive sunlight, the differential amplifier 5X detects the difference in the outputs of these photodetecting elements, rotates the servo motor 6X, and rotates the support frame shown in Figure 1. 3 is rotated to face the sun, the output signal from the photodetector element _4x1 disappears, the input signal to the differential amplifier 5X becomes balanced, and the servo motor 6X stops. After that, servo motor 6X
is controlled so that the outputs of the photodetecting elements 4x ₁ and 4x ₁ ' are balanced, and the solar light condensing device always faces the direction of the sun and can reliably collect solar energy. Note that during tracking, there are often cases where sunlight is temporarily blocked by clouds, etc.
In such a case, the amount of incident light on the photodetecting elements 4x ₁ and 4x ₁ ' will be equal, so during that time the tracking operation will remain stable in an equilibrium state, and after a predetermined period of time, the clouds will break and sunlight will be received again. Then, if the movement of the sun during that time is within 30 degrees in the case of the illustrated example, one of the photodetecting elements 4x ₁ and 4x ₁ ' will receive sunlight and the other will not, so it will be the same as above. Then, the servo motor 6X operates so that both inputs of the differential amplifier 5X are balanced, and the sun's position is tracked again. Note that in the above, the photodetecting elements 4x ₁ , 4
Although we have explained an example in which x ₁ ' is placed near the outside of the periphery of the light beam focused by lens system 1, it works similarly even if it is placed near the inside of the periphery or on the boundary line of the periphery. It may be configured to follow the position. However, when installing near the outside of the peripheral area, the servo motor is operated to prevent sunlight from entering the photodetecting elements 4x ₁ and 4x ₁ ', so there is no risk of the photodetecting elements being burned out by the solar energy they receive. There's no fear. Moreover, as described above, a pair of photodetecting elements 4
We have explained an example of following the movement of the sun during the day using the photodetecting elements 4x 1 and 4x _{1 '} , but as shown in the figure, the photodetecting elements 4x ₁ and 4x ₁ ' A pair of photodetecting elements 4y ₁ and 4y ₁ ' are provided, and the difference in the outputs of these photodetecting elements 4y ₁ and 4y ₁ ' is simultaneously detected by the differential amplifier 5Y to control the servo motor 6Y. It can also be made to follow the height of the sun during the four seasons, and can be made to follow the movement of the sun throughout the year.

Therefore, if the photodetecting elements 4x ₁ and 4x ₁ ' are located at the periphery of the light beam focused by the lens system 1,
It can be placed at any desired position between the lens system 1 and the light collecting means 2, and the closer it is to the lens system 1, the more the position of the sun can be detected within a wider range. On the other hand, the closer the light collecting means 2 is, the narrower the range in which the sun's position is detected, but the sun's position can be tracked more accurately.

The present invention has been made from the above-mentioned viewpoints, and FIG. 4 is a diagram for explaining an embodiment of the automatic tracking device according to the present invention, and FIG. This is a diagram showing the views seen from above side by side, and the shaded area _S1 in Figure 5 is the fourth
In the figure, the sun image on the - plane, the shaded area S ₂ is -
4y ₁ , 4y _{1 ' and 4x 2 , 4x 2 '; 4y 2 , 4y 2 ' are} arranged around the solar images. Ori,
The outputs of the photodetecting elements 4x ₁ and 4x ₂ are sent to one input terminal of the differential amplifier 5X through an OR circuit 4x ₁₂ , and the outputs of 4x ₁ ' and 4x ₂ ' are sent to one input terminal of the differential amplifier 5X through an OR circuit 4x' ₁₂ . Connected to another input terminal. Similarly, the outputs of the photodetecting elements 4y ₁ and 4y ₂ are passed through the OR circuit 4y ₁₂ to one input terminal of the differential amplifier 5Y, and the outputs of 4y ₁ ′ and 4y ₂ ′ are connected to the OR circuit 4
It is connected to the other input terminal of the differential amplifier 5Y through _y'12 . Therefore, according to this example:
The photodetecting elements 4x ₁ , 4x ₁ ′; 4y ₁ , 4y ₁ ′ detect the position of the sun within a wider range and cause the concentrator to approximately follow the direction of the sun.
x ₂ , 4x ₂ ′; 4y ₂ , 4y ₂ ′ allows for more accurate tracking of the sun's position. In addition, in the present invention, the photodetecting elements 4x ₂ , 4x ₂ '; 4y ₂ , 4
Since y ₂ ' is arranged near the focal point of lens system 1,
The amount of light received is large and there is a risk of burnout, but in that case, if a heat and light attenuation member such as a heat absorber or reflector is provided in front of the photodetector, the photodetector 4x ₁ , 4x ₁ ′; 4y ₁ , 4y ₁ ′ and 4x ₂ , 4x ₂ ′; 4
The same material can be used for y ₂ and 4y ₂ '. In addition, in FIG. 5, photodetecting elements 4x ₁ and 4x ₂
The output of is passed through OR circuit 4x ₁₂ to differential amplifier 5x
and leads to one input terminal of the photodetector element 4.
An example has been shown in which the outputs of x ₁ ' and 4x ₂ ' are led to the other input terminal of the differential amplifier _5X through the OR circuit 4x _{' 12} . At the same time, the difference between the outputs of the photodetecting elements 4x ₂ and 4x ₂ ' is determined using a second differential amplifier, and the OR output of these first and second differential amplifiers It is easy to understand that the servo motor 6X may be driven, and the outputs of the photodetecting elements 4y ₁ , 4y ₁ ′; 4y ₂ , 4y ₂ ′ may be similarly configured to drive the servo motor 6Y. .

Although an example in which the present invention is applied to a solar energy collection device has been described above, it will be easily understood from the above description that the present invention can be used to automatically track light sources other than sunlight. It is also possible to use the automatic tracking device according to the present invention by mounting it on a moving object that moves irregularly, but as explained above, the automatic tracking device according to the present invention can detect light sources within a wide area. For example, even if the position of the light source is temporarily lost due to the irregular movement of a moving object, the position of the light source can be immediately detected and the position of the light source can be accurately detected. The effect is particularly great when this device is installed at offshore facilities or the like.

As is clear from the above description, according to the present invention, the position of a light source within a wide area can be easily detected with a simple configuration, and the light detecting element can be used to detect the light beam focused by the lens system. Since it is provided near the outside of the periphery, there is no fear that the photodetecting element will be burned out by the energy of the light source that it receives, and it can accurately follow the movement of the light source.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram for explaining the animal principle of the automatic tracking device according to the present invention, and FIG.
3 is an optical diagram for explaining the animal principle of the present invention, and FIG. 4 is a schematic diagram for explaining the embodiment of the present invention. The configuration diagram, FIG. 5, is a plan view and an electric circuit diagram seen from the - plane and - plane of FIG. 4. 1... Lens system, 2... Light collection means, 3... Support frame,
4x ₁ , 4x ₁ ′; 4y ₁ , 4y ₁ ′; 4x ₂ , 4x ₂ ′, 4y ₂ ,
4y ₂ ′...Photodetection element, 5X, 5Y...Differential amplifier,
6X, 6Y...Servo motor.

Claims (1)

[Claims] 1 a lens system for focusing light from a tracked object; a first light detection means disposed on a first plane at a position between the lens system and the focal point of the lens system; a second light detection means disposed on a second plane at a position different from the first plane between the lens system and the focal point of the lens system; The first and second light detecting means are comprised of an integral structure integrally configured with a light detection means, and a driving means for directing the lens system of the integrated structure in the direction of the tracked object, and the first and second light detection means teeth,
each has at least one pair of photodetecting elements located near the outside of the periphery of the light beam focused by the lens system and at symmetrical positions with respect to the central axis of the lens system; The voltage difference between the output signals of the pair of photodetecting elements in the detection means and the output signal of the pair of photodetecting elements of the second photodetecting element disposed in the same direction as the first pair of photodetecting elements. An automatic tracking device characterized in that the lens system is directed toward the tracked object by being controlled by the drive means so that the differential voltages are balanced.