JPH0575610U - Solar tracking device - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention aims to detect the position of sunlight with high detection accuracy with little change over time, and thus to track sunlight with high accuracy. [Structure] Horizontal sunlight passing through the slits 15A and 15B,
CCD / linear sensors 14A and 14B for vertical detection
And a position data detection circuit that obtains position data in the horizontal and vertical directions of sunlight based on the outputs of both sensors 14A and 14B, and a horizontal direction based on preset position data in the horizontal direction and position data in the horizontal direction of sunlight. A subtraction circuit that calculates a displacement amount to be supplied to the drive device, and a subtraction circuit that calculates a displacement amount to be supplied to the vertical direction drive device based on preset position data in the vertical direction and position data in the vertical direction of sunlight. It is characterized by being composed of.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a sunlight tracking device that detects the position of sunlight and tracks the sunlight, and more particularly to a solar tracking device that performs sunlight tracking by digital processing.

[0002]

[Prior Art]

 In the solar tracking device that performs solar tracking, it is necessary to detect the position of the sunlight, and therefore the solar position detection device is used. The conventional sunlight position detecting device mainly uses two or a plurality of photosensors such as photodiodes and detects the position by differentially using these analog outputs. However, since this differential type detection device performs detection by analog signal processing, there is a problem in that the accuracy of detection decreases as the sensor element undergoes considerable changes over time, such as output drop and drift.

Further, if a correction circuit for correcting these secular changes is provided, the entire configuration becomes complicated and the price of the device becomes expensive, which is a new problem. Further, in such a differential type detection device, it is necessary to precisely set the positional relationship between the sun and the sensor.

Further, conventionally, there is a device using a PSD (Position Sensitive Dev ice) in addition to the above-mentioned differential type detection device, but in this case as well, since detection is performed by analog signal processing, there is a secular change or There is a problem such as drift due to temperature.

[0005]

[Problems to be solved by the device]

 As described above, in the related art, since the detection process is performed in an analog manner, there is a drawback that the detection error becomes large and the accuracy decreases.

The present invention has been made in consideration of the above circumstances, and its purpose is to detect the position of sunlight with high detection accuracy with little change over time, and thus to track solar light with high accuracy. It is to provide a solar light tracking device capable of performing.

[0007]

[Means for Solving the Problems]

 The solar light tracking device of this invention is installed in a dark box having first and second dark chambers, first and second slits provided in the first and second dark chambers, and in the first dark chamber. A first one-dimensional solid-state imaging device composed of a plurality of pixels for horizontally detecting sunlight passing through the first slit; and a second dark room installed in the second dark room. Second one-dimensional solid-state imaging device composed of a plurality of pixels for vertically detecting sunlight passing through the slit, and the sun based on the outputs of the first and second one-dimensional solid-state imaging devices. First and second position data detection circuits for obtaining position data in the horizontal and vertical directions of light, and preset position data in the horizontal direction and sunlight obtained by the first position data detection circuit. Based on the position data in the horizontal direction, provide it to the horizontal direction drive device. Based on the first displacement amount calculating means for calculating the displacement amount for adjusting the vertical position and the preset position data in the vertical direction and the position data in the vertical direction of the sunlight obtained by the second position data detection circuit. A second displacement amount calculation means for calculating a displacement amount to be supplied to the driving device, wherein each of the first and second position data detection circuits sequentially outputs pixels of the one-dimensional solid-state imaging device. A comparison circuit that generates a pulse signal by comparing a signal obtained by reading and scanning with a predetermined threshold level, a frequency division circuit that divides the output pulse signal of the comparison circuit by ½, and the one-dimensional solid state. When the read signal level of the image pickup device is less than or equal to the threshold level, the signal corresponding to the synchronization signal used when reading the signal from the one-dimensional solid-state image pickup device is counted to perform the one-dimensional solid-state image pickup. After the device of the readout signal level is equal to or higher than the threshold level is characterized by being composed of a counter circuit for counting an output pulse signal from the frequency divider.

[0008]

[Action]

 In the solar light tracking device of the present invention, the first and second position data detection circuits are used for reading a signal from the one-dimensional solid-state imaging device when the read signal level of the one-dimensional solid-state imaging device is less than or equal to a predetermined threshold value. The number of pixels from the pixel at one end of the one-dimensional solid-state imaging device to the end of the area where sunlight of a predetermined light amount or more is radiated is obtained by counting the signal corresponding to the synchronized signal by the counter circuit. Is obtained. After the read signal level from the 1-dimensional solid-state imaging device exceeds the threshold value, the counter circuit counts the pulse signals from the frequency dividing circuit to irradiate the 1-dimensional solid-state imaging device with more than the predetermined amount of sunlight. The number of pixels up to the center of the displayed area is obtained. The number of both pixels is the position data of sunlight in the horizontal and vertical directions, and the position data of sunlight in the horizontal and vertical directions obtained by the first and second position data detection circuits is the same as the preset position data. The displacement amounts are supplied to the first and second displacement amount calculation means, and the displacement amounts to be supplied to the horizontal and vertical direction drive devices are calculated by these first and second displacement amount calculation means.

[0009]

【Example】

 The present invention will be described below with reference to the drawings.

First, the principle will be described before the description of the embodiments of the present invention. FIG. 4 is a diagram for explaining the principle of the solar light tracking device according to the present invention. In the figure, 14 is a one-dimensional sensor in which a plurality of pixels SC are arranged in a line, and 16 is a slit plate. Here, the sensor 14 is irradiated with the sunlight 18 through the slit plate 16. At this time, the slit width of the slit plate 16 is S, the incident angle of the sunlight 18 is θ, the distance between the slit plate 16 and the light receiving surface of the sensor 14 is d, and the viewing angle of the sun is α (viewed from the viewpoint). It is the apparent size of the sun, usually about 0.54 °), the photosensitive width on the sensor is b, the number of pixels of the sensor 14 is N, the slit center of the slit plate 16 is C, the slit center C is on the sensor. The photosensitive width b on the sensor is given by the following equation, where C'is the orthogonal projection of C and Cs is the center of the sunlight incident from the slit on the sensor. However, at this time, the diffraction effect at the slit edge is ignored. b = S + d [cot {θ− (α / 2)} − cot {θ + (α / 2)] = S + d · sinα / [sin {θ− (α / 2)} · sin {θ + (α / 2)] … 1

As is clear from the above formula 1, the photosensitive width b is a function of the slit width S and the viewing angle α of sunlight, and has a peak having a certain width (plateau). However, this width is sufficiently larger than the value calculated by the diffraction effect at the slit edge. Then, by detecting the sensor center Cs, which is the center of the above-mentioned photosensitive width b, the distance between C ′ and Cs can be obtained, and the incident angle θ of sunlight can be determined from the relationship between this distance and the distance d. You can ask. The position of the sunlight can be detected by providing the detecting means for such an angle θ in the horizontal direction and the vertical direction, respectively. Next, an embodiment of the solar light tracking device of the present invention will be described.

3A and 3B show the external appearance of the entire sunlight position detecting device used in the solar light tracking device according to the present invention. FIG. 3A is a perspective view, FIG. (C) is a top view which shows the upper part of this sunlight position detection apparatus open.

In the figure, 10 is a dark box. Inside the dark box 10, a dark room 12 partitioned by a partition plate 11 is provided. Furthermore, this dark chamber 12 is divided into two chambers 12A and 12B by a separator 13, and in order to detect sunlight in the horizontal direction (X direction) on the partition plate 11 in one chamber 12A, A one-dimensional solid-state imaging device, for example, a CCD / linear sensor 14A, which is configured by arranging a plurality of pixels in a line, is installed. Similarly, a CCD linear sensor 14B for detecting sunlight in the vertical direction (Z direction) is installed on the partition plate 11 in the other chamber 12B.

In front of the dark room 12, as shown in FIG. 3B, an X-direction slit 15A and a Z-direction sensor 15A extending in a direction orthogonal to the pixel array of the X-direction sensor 14A are provided. A slit plate 16 provided with a Z-direction slit 15B extending in a direction orthogonal to the 14B pixel array is arranged, and in front of this slit plate 16, a light attenuation glass made of a heat ray reflecting glass or a heat ray absorbing glass or the like. Filter 17 is arranged. Then, when detecting the sunlight position, the front of the dark box 10 is installed so as to face the sunlight.

FIG. 1 is a circuit diagram showing a configuration of an electric circuit for processing a signal obtained by the X-direction sensor 14A or the Z-direction sensor 14B, and FIG. 2 is a timing chart thereof. Since this electric circuit has the same configuration for both the X and Z direction sensors, only one of the circuits will be described below.

The sensor 14 includes a transfer pulse φT, a reset pulse φR, two-phase shift pulses φA and φB, and their inversion pulses / φA and / φB (however, as shown in FIG. 2). In 2, the inversion pulses / φA and / φB are driven by not shown. That is, the sensor 14 sequentially reads the signals of each pixel in synchronization with the two-phase shift pulses φA and φB and their inversion pulses / φA and / φB after the transfer pulse φT is supplied, and the pixels for which reading has been completed Signal is reset based on the reset pulse φR. As a result, as shown in FIG. 2, the sensor 14 sequentially outputs the voltage signal SO corresponding to the irradiation light amount of sunlight for each pixel. That is, the voltage signal SO output from the sensor 14 is a comb signal having a voltage corresponding to the sunlight level for each pixel.

The signal SO is supplied to the comparator 21, which is given a predetermined threshold voltage. The comparator 21 outputs the "1" level signal only when the level of the signal SO is higher than the level of the threshold value Vth. Therefore, as shown in FIG. 2, the comparator 21 outputs a pulsed signal CO when the signal SO is equal to or higher than the Vth level.

The signal CO from the comparator 21 is supplied to the frequency dividing circuit 22 and the signal detecting circuit 23. The frequency dividing circuit 22 divides the signal CO by 1/2 and supplies the signal .phi.a as shown in FIG. 2 to the digital multiplexer 24 as one input. The signal detection circuit 23 generates the detection signal φD which becomes the "1" level at the timing when the signal CO rises to the "1" level for the first time.

The other input of the digital multiplexer 24 is supplied with the OR pulse / φR of the reset pulse φR and the inverted pulse / φT of the transfer pulse φT / φR · / φT. The signal φD is supplied to the multiplexer 24 as a selection control signal, and the multiplexer 24 selects the signal / φR / φT when the signal φD is at “0” level, and the signal φD is at “1” level. In this case, the signal φa is selected.

The selection output φci from the multiplexer 24 is counted by the counter circuit 25. The counter circuit 25 is reset at a predetermined cycle based on the reset pulse φSR. The count output Ncl is supplied to the latch circuit 26.

The detection signal φD is supplied to the latch circuit 26 in addition to the count output Ncl of the counter circuit 25, and these are latched based on the latch pulse φL. The count value Ncl latched by the latch circuit 26 is supplied to the arithmetic circuit 27. The arithmetic circuit 27 calculates the incident angle θ of the sunlight in the direction (X direction or Z direction) from the count value Ncl from the latch circuit 26 and various values given in advance.

Here, when the voltage signal SO of each pixel read from the sensor 14 is lower than the threshold voltage (Vth level), the synchronization signal / φR · corresponding to each pixel of the sensor 14 is input to the counter circuit 25. / ΦT is supplied. For this reason, in this period, the counter circuit 25 counts the number of pixels from the pixel at one end of the sensor 14 to the end of the region where sunlight having a predetermined light amount or more (corresponding to the voltage level Vth) is irradiated. It will be. Further, when the signal SO becomes higher than the threshold voltage level, φ a is supplied as the input of the counter circuit 25. Since this signal φa is a 1/2 frequency-divided signal of the signal SO output corresponding to each pixel, the counter circuit 25 is illuminated by the sensor 14 with more sunlight than the predetermined amount of light during this period. The number of pixels from the edge pixel to the central pixel of the area is counted.

Therefore, the count value Ncl of the counter circuit 25 corresponds to the number of pixels from the end portion of the sensor 14 to the central portion of the area where sunlight having a predetermined light amount or more is irradiated. That is, if the number of the pixel located at the end of the sensor 14 on the A side in the principle diagram of FIG. 4 is na and the number of the last pixel exceeding the threshold voltage level Vth is nb, Ncl is given by the following equation. Given in. Ncl = na-1 + {(na + nb + 1) / 2} ... 2

The value Ncl given by this equation is the number of the pixel Cs in FIG. This value is the center value of the sunlight incident on the slit 15 on the sensor 14, and is not affected by the width of the slit 15.

Further, the arithmetic circuit 27 has a distance d (distance between the slit plate and the light receiving surface of the sensor) in FIG. 4, a width a of one pixel of the sensor, and a projection of the slit center C on the sensor. The number Nc 'of the pixel C'at the position corresponding to is given in advance. By the way, the above d, a, Ncl, Nc ′ and the incident angle θ of sunlight have a relationship such as d tan θ = (Ncl−Nc ′). Therefore, the arithmetic circuit 27 calculates the incident angle θ on the basis of the following three expressions derived from the above relationship. θ = tan ^-1 (a / d) (Ncl-Nc) ... 3

Further, the output φD from the signal detection circuit 23 enables distinction between fine weather and cloudy weather and detection of the presence or absence of sunlight. That is, the light incident from the slit 15 is a mixture of direct light from the sun and scattered light. When there are many direct light components, a large peak appears in the sensor output. (A), (b), and (c) of FIG. 5 are fine weather, sunset or sunrise, and cloudy weather (the cloudy weather here means that there is no direct light from the sun and only scattered light components are incident. It is a figure which shows the sensor output waveform in each case. In addition, e in FIG. 5 is a scattered light component. Therefore, if a predetermined threshold voltage level Vth is set by the comparator 21 and the signal φD from the signal detection circuit 23 rises to the "1" level, it means that it is either fine weather, sunset, or sunset. On the other hand, if the signal φD does not rise to the “1” level and remains at the “0” level, it can be determined that it is cloudy.

In this sunlight position detecting device, since the detecting means for the angle θ is provided in two systems, one for the horizontal direction and the other for the vertical direction, it is necessary to recognize the position of the sunlight based on the detected angle θ in both means. You can The minimum measurable angle θ min in this embodiment is given by the following equation near Nc ′. θ min = tan ^-1 (a / d) ... 4

The measurable range is given by tan ⁻¹ (a / d) (1-Nc ′) to tan ⁻¹ (a / d) (N−Nc ′). Especially when Nc 'is in the center of the sensor, it becomes approximately ± tan ^-1 (a / 2d) N. That is, when N and a are constant, the minimum measurable angle and measurable range can be determined by appropriately setting d.

FIG. 6 is a sectional view in the length direction of the slit. The vertical sensitivity of the sensor 14 depends on l and d, where l is the length of the slit. When the sensor 14 is placed at the center of the slit, the measurable range is about ± tan ^-1 (l / 2 d) with respect to the vertical direction of the sensor, and the range can be freely adjusted by setting l. be able to.

As described above, in the sunlight position detecting device having the above-described configuration, since the signal processing after the comparator 21 is digitally performed, compared with the conventional case where all analog processing is performed. The secular change is small and the error is small, which can improve the detection accuracy.

Next, an embodiment of the solar light tracking device of the present invention using the solar light position detecting device having the above-mentioned configuration will be described. FIG. 7 is a block diagram showing a partial configuration of the solar light tracking device. The position data based on the angle θ 1 of sunlight in the X direction obtained by the sunlight position detecting device is supplied to the subtraction circuit 31 as one input. The subtraction circuit 31 is supplied with preset position data as the other input. Then, the X-direction displacement amount calculated by the subtraction circuit 31 is supplied to an X-axis drive device (not shown). Similarly, the position data based on the angle θ of the sunlight in the Z direction obtained by the sunlight position detecting device is supplied to the subtraction circuit 32 as one input and the preset position data as the other input. Then, the Z-direction displacement amount calculated by the subtraction circuit 32 is supplied to a Z-axis drive device (not shown). In this way, by controlling the operation of the drive unit based on the difference between the preset position data and the current position data, sunlight will enter the position determined by the preset position data of the sensor, Optical tracking is realized.

Since this tracking operation is controlled only by digital numerical calculation processing, ambiguity such as drift is eliminated as compared with the case where the operation is controlled based on the analog value. Moreover, since the relative positional relationship between the sensor and the sun is also determined by the preset position data, complicated adjustments such as alignment are unnecessary. Further, if a position encoder is provided in the drive device that operates based on the difference between the preset position data and the current position data, the absolute position of the sun can be detected. Furthermore, if the sensor is fixed, the absolute position of the sun can be calculated within the sensor measurable range by a numerical value calculation process. Furthermore, if a lens or the like is placed in front of the sensor, a wider range of measurement becomes possible.

It is needless to say that the present invention is not limited to the above embodiment and various modifications can be made. For example, in the above-mentioned embodiment, the case where the sensor 14 is a CCD / linear sensor has been described, but a line sensor having the same operation as a CCD sensor such as a MOS type may be used.

[0034]

[Effect of the device]

 As described above, according to the present invention, it is possible to provide a sunlight tracking device capable of detecting the position of sunlight with high detection accuracy with little change over time and capable of tracking sunlight with high accuracy. it can.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of an electric circuit of a sunlight position detecting device used in the sunlight tracking device of the present invention.

FIG. 2 is a timing chart of the electric circuit of FIG.

3A and 3B are external views of the sunlight position detecting device, wherein FIG. 3A is a perspective view, FIG. 3B is a front view, and FIG.

FIG. 4 is a diagram for explaining the principle of the solar light tracking device according to the present invention.

5 shows a sensor output waveform of the electric circuit of FIG.
(A) is a waveform diagram at the time of fine weather, (b) is a waveform diagram at the time of sunset or sunrise, (c) is a waveform diagram at the time of cloudy weather.

FIG. 6 is a diagram showing a relationship between a slit and a sensor in the sunlight position detecting device.

FIG. 7 is a block diagram showing a partial configuration of the solar light tracking device of the present invention.

[Explanation of symbols]

10 ... dark box, 14 ... CCD / linear sensor, 15 ... slit,
21 ... Comparator, 22 ... Frequency divider circuit, 23 ... Signal detection circuit,
24 ... Digital multiplexer, 25 ... Counter circuit, 26
... Latch circuit, 27 ... Arithmetic circuit, 31, 32 ... Subtraction circuit.

Claims (1)

[Scope of utility model registration request] 1. A dark box having first and second dark chambers, first and second slits provided in the first and second dark chambers, and a dark box installed in the first dark chamber. A first one-dimensional solid-state imaging device including a plurality of pixels that horizontally detect sunlight passing through one slit, and is installed in the second dark room, and passes through the second slit. A second one-dimensional solid-state imaging device including a plurality of pixels for detecting sunlight in the vertical direction, and horizontal and vertical directions of the sunlight based on the outputs of the first and second one-dimensional solid-state imaging devices. First and second position data detection circuits for obtaining position data in the horizontal direction, and horizontal drive based on preset position data in the horizontal direction and position data in the horizontal direction of sunlight obtained by the first position data detection circuit. Displacement amount to supply to the device First displacement amount calculating means for calculating, and vertical position data for the sunlight based on the preset position data in the vertical direction and the position data in the vertical direction of the sunlight obtained by the second position data detection circuit. A second displacement amount calculating means for calculating a displacement amount, wherein each of the first and second position data detection circuits reads a signal obtained by sequentially reading and scanning pixels of the one-dimensional solid-state imaging device. A comparison circuit that generates a pulse signal by comparing with a predetermined threshold level, a frequency division circuit that divides the output pulse signal of the comparison circuit into 1/2, and a read-out signal level of the one-dimensional solid-state imaging device is the threshold value. When the level is lower than the level, the signal corresponding to the synchronization signal used when reading the signal from the one-dimensional solid-state imaging device is counted, and the read signal level of the one-dimensional solid-state imaging device is counted. A solar tracking device comprising: a counter circuit that counts the output pulse signal from the frequency divider circuit after the bell becomes equal to or higher than the threshold level.