Solar servo control tracking device

A solar servo control tracking device is disclosed. The device includes: an integrated control device having a solar cell sensor unit detecting luminance at a solar azimuth, and an integrated control panel transmitting a control signal at a maximal solar azimuth, calculated by comparing a solar azimuth from the luminance at a solar azimuth; and solar tracking devices, respectively having a tracking device controller receiving the control signal via a wireless link, a high torque driving unit with an AC single phase inductor to generate driving torque by the control signal from the tracking device controller, solar module assemblies driven by the high torque driving unit to track the solar azimuth in accordance with the control signal, and an operating angle sensor unit installed to the high torque driving unit to detect operating angles of the solar module assemblies that track the sun by the control signal.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a solar servo control tracking device, and more particularly, to a solar servo control tracking device remotely servo-controlling and remotely monitoring a solar module assembly and being smoothly driven in accordance with a solar azimuth.

2. Description of the Related Art

An existing solar tracking device uses a power transmission including a direct current (DC) motor and a worm gear to provide a driving force to a photo-conductive cell (CdS) and a solar module assembly by measuring luminance and a proximity sensor to detect a rotation angle of the tracking device.

However, the related art has the following disadvantages:

Since the existing CdS type light sensor is fixed to top of the solar module assembly to detect a solar azimuth entered in a specific azimuth, it is difficult to detect the solar azimuth when weather is changeable, that is, alternating cloudy and clear.

The existing CdS type light sensors are attached to the top of every solar module assembly one by one so that cost increases, and due to characteristics of the CdS, the solar azimuth detected by the tracking device in a power station has a large error range.

A drive unit using an existing DC motor has insufficient driving torque to drive more than six solar module assemblies.

Since a DC motor is employed as a driving source of the solar module assembly and a switching mode power supply converting commercial AC 220V into DC power is required, that becomes an economic burden.

Since a driven angle of the solar module assembly is estimated by counting pulses generated per one revolution using a proximity sensor in order to detect the driven angle of the solar module assembly, it is difficult to precisely control the driven angle of the solar module assembly.

Artificial manipulation is required in order to maintain the horizontal stability of the solar module assembly in order to prevent damage from, for instance, a typhoon at the site to which a typhoon is coming.

Since the solar module assembly is independently driven and there is no function of monitoring the same, an operator must visit the site at which the solar module assembly is installed to inspect it. Therefore, it is expensive to maintain the solar module assembly.

SUMMARY OF THE INVENTION

Therefore, the present invention has been made in view of the above problems, and the present invention provides a solar servo control tracking device performing remote servo-control and remote monitoring of a plurality of solar module assemblies through remote communication by a control signal in accordance with a solar azimuth measured by a single solar cell sensor, and smoothly driving six or more solar module assemblies in which a plurality of solar panels is arranged in the form of a matrix to produce a maximal electric power with a single power transmission, so that expense can be cut down and efficiency of generating electricity from the solar energy can be maximized.

In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of a solar servo control tracking device comprising: an integrated control device including: a single solar cell sensor unit detecting luminance of sunrays with respect to a solar azimuth; and an integrated control panel remotely transmitting a control signal based on a maximal solar azimuth that is calculated by comparing a solar azimuth based on the luminance of sunrays detected by the solar cell sensor unit with a solar azimuth measured in real time; and a plurality of solar tracking devices, each of the solar tracking devices including: a tracking device controller remotely receiving the control signal through a wireless communication; a high torque driving unit having an AC single phase inductor to generate a driving torque by servo-control of the tracking device controller in accordance with the control signal; a plurality of solar module assemblies driven by the high torque driving unit to track the solar azimuth in accordance with the control signal; and an operating angle sensor unit installed to the high torque driving unit to detect a plurality of operating angles of the solar module assemblies that track the sun in accordance with the control signal.

The integrated control panel and each of the tracking device controllers further include a wireless communication module, a TCP/IP communication module, and either an RF communication module or a Bluetooth communication module to remotely monitor operating states of the solar module assemblies and the solar cell sensor unit with respect to the solar azimuth through the wireless communication modules-and to remotely control the integrated control panel and the tracking device controllers through the TCP/IP communication modules and either the RF communication modules or the Bluetooth communication modules when the solar module assemblies and the solar cell sensor unit cannot track the sun in accordance with the solar azimuth.

Each of the high torque driving units is installed at the middle of the solar module assemblies, and comprises: an AC single phase inductor driven by a servo-control performed by the tracking device controller; a cooling fan attached to the AC single phase inductor to cool the AC single phase inductor; a primary reducer, a secondary reducer, and a third worm reducer, sequentially connected to the AC single phase inductor to generate a high torque, the third worm reducer having a pinion and a worm wheel to which the adjusting shaft of the solar module assembly is installed.

The operating angle sensor unit comprises: a sensor pinion connected to the pinion; a sensor worm wheel connected to the sensor pinion; and an operating angle sensor installed to the rotation shaft of the sensor worm wheel.

The operating angle detected by the operating angle sensor is transmitted to the integrated control panel through the tracking device controller.

The solar cell sensor unit comprises: a stepping motor providing rotary power in order to measure an incident angle of sunrays entering at a maximal luminance such that a solar cell scans luminance of 30° to 150°; a solar cell rotation shaft transmitting the rotary power of the stepping motor; a rotation angle sensor measuring an azimuth with respect to the luminance of the sunrays; a solar cell installed to the solar cell rotation shaft to measure the luminance of the sunrays; a base plate having supports to which the stepping motor, the solar cell rotation shaft, and the rotation angle sensor are installed; a case installed on the base plate to enclose and protect the stepping motor, the solar cell, the solar cell rotation shaft, and the rotation angle sensor; a transparent semi-spherical body installed on the top of the case to protect the components from moisture; and from water from entering the case and a water-proof connector installed to the case to connect an electric power wire and a control signal wire for input from the integrated control panel to the stepping motor and for output of the signal from the rotation angle sensor.

The integrated control panel measures the luminance of sunrays in a range of 30 degrees to 150 degrees through the solar cell sensor unit, analyses the measured luminance of sunrays with respect to the operating angle detected by the operating angle sensor units to set an operation angle range for the maximum luminance, and compares the solar azimuth measured in real time with the operating angle range at the maximum luminance to calculate an operating angle control signal of the solar module assemblies and to transmit the operating angle control signal to the tracking device controllers via a wireless line. Each of the tracking device controllers receives the operating angle control signal from the integrated control panel to calculate an error of the operating angle measured by the operating angle sensor unit, performs the compensation by the proportional-integral-derivative (PID) servo-control using the calculation to drive the AC single phase inductor so as to drive the solar module assembly, and transmits the operating angle of the solar module assembly and the phase current signal of the AC single phase inductor to the integrated control panel via a wireless link when the solar module assembly malfunctions in being unable to track in accordance with the operating angle control signal.

The integrated control panel receives the operating angles of the solar module assemblies and the measured phase currents of the AC single phase inductors from the tracking device controllers via a wireless link to transmit the operating angle control signals to the tracking device controllers to be operated by the operating angle control signals, or to transmit control signals to the tracking device controllers to stop the solar module assemblies when the AC single phase inductors are in an over current state.

Each of the solar module assemblies comprises solar panels of a 4*4 matrix array and the number of the solar module assemblies is at least six.

The integrated control panel comprises: a manual/automatic mode switch selected by an operator; a real time counter to which a period is set to measure the solar azimuth in real time; a first buffer circuit to which a rotation angle of the solar cell sensor unit is input through the manual/automatic mode switch selected by the operator; a second buffer circuit to which the luminance of sunrays, measured at the rotation angle by the solar cell sensor unit by the selection of the manual/automatic mode switch, is input; a microcomputer receiving the rotation angles of the first and second buffer circuits and the luminance of sunrays to output a rotation angle control signal through Darlington transistors to the solar cell sensor unit, and outputting an operating angle control signal with respect to a maximal solar azimuth calculated by comparing the solar azimuth with respect to the luminance of sunrays with a solar azimuth that is measured in real time in accordance with the period of the real time counter; a wireless communication module transmitting the operating angle control signal to the tracking device controllers; a memory in which data of phase current of the AC single phase and the operating angles of the solar module assemblies received from the tracking device controllers through the wireless communication module are stored; and a TCP/IP communication module transmitting the phase current and operating angle data read and outputted from the memory by the microcomputer.

Each of the tracking device controllers comprises: a manual/automatic mode switch selected by an operator; a buffer circuit to which the operating angle of the solar module assembly detected by the operating angle sensor unit is inputted when the automatic mode of the manual/automatic mode switch is selected by the operator; wireless communication modules receiving an operating angle control signal remotely transmitted by the integrated control panel; a microcomputer having a memory storing the operating angle and the phase current of the AC single phase inductor and outputting a servo-control signal for a proportional-integral-derivative (PID) servo-control of the solar module assembly to the AC single phase inductor of the high torque driving unit through a forward relay and a reverse relay in accordance with a value calculated from the operating angle inputted through the buffer circuit and the operating angle control signal inputted through the wireless communication modules to control the operating angle of the solar module assembly; and either an RF communication module or a Bluetooth communication module remotely transmitting data on the operating angle and the phase current of the AC single phase inductor stored in the memory.

The microcomputer of the integrated control panel further outputs a maximal solar azimuth; the wireless communication module of the integrated control panel remotely transmits the outputted maximal solar azimuth to the tracking device controllers; each of the tracking device controllers further comprises: a real time counter in which a period is set to measure the solar azimuth by time period in real time; the wireless communication modules of the respective tracking device controllers which remotely receive the maximal solar azimuth. Each of the microcomputers of the tracking device controllers compares the maximal solar azimuth remotely received through the wireless communication modules with the solar azimuth calculated by a real time azimuth equation using the real time counter, and outputs only the verified operating angle control signal to the AC single phase inductors of the high torque driving units.

The integrated control panel further comprises: a horizontal position angle correction mode switch that initially sets the horizontal angles of the solar module assemblies; and a time setting mode switch that sets an initial time of the integrated control panel in real time.

Each of the tracking device controllers further comprises: a horizontal position angle correction mode switch that initially sets the horizontal angles of the solar module assemblies; and a time setting mode switch that sets an initial time of each of the tracking device controllers in real time.

According to the present invention, since accuracy, rapid response, and tracking accuracy with respect to the operating angle control performed for the solar module assemblies are improved, efficiency of photovoltaic power generation can be optimized, and a plurality of solar module assemblies can be controlled in an optimized state, at once, by a single solar cell sensor unit. The high torque driving unit can generate a high torque to drive the solar module assemblies with 20% higher weight than the existing solar module assemblies so that efficiency of the photovoltaic power generation can be maximized.

In other words, the photovoltaic power generation can be maximized by the high torque driving unit capable of tracking sun rays while loaded with the proposed solar module assemblies with 20% more weight than the existing ones, the integrated control panel calculating an optimal solar azimuth, and the integrated control panel and the tracking device controllers installed with remote communication modules remotely monitoring the operating angles of the solar module assemblies and the operation states of the AC single phase inductors in order to track the sunrays and perform remote servo-control.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 to 11illustrate a technical configuration of an integrated control device and a solar servo-control tracking device according to an embodiment of the present invention, in which:FIG. 1is a view illustrating technical configuration of a solar servo-control tracking device according to an embodiment of the present invention;FIG. 2is a plan view illustrating an assembly of a single solar module assembly of the solar servo-control tracking device according to the embodiment of the present invention;FIG. 3is a front view illustrating a solar tracking device according to the embodiment of the present invention; andFIG. 4is a side view of the solar tracking device inFIG. 3and illustrating an operating range of a driving angle.

FIG. 5is a detailed front view illustrating the structure of a power transmission of the solar tracking device,FIG. 6is a right-side view of a power driving unit of the solar servo-control tracking device inFIG. 5,FIG. 7is a left-side view of the power driving unit of the solar servo-control tracking device inFIG. 5,FIG. 8is an enlarged view illustrating an operating angle sensor unit inFIG. 5, andFIG. 9is an enlarged view illustrating the operating angle sensor unit inFIG. 7.

FIG. 10is a photograph illustrating an actual appearance of a solar cell sensor unit of the solar servo-control tracking device according to the embodiment of the present invention, andFIG. 11is a photograph illustrating an actual structure of the solar cell sensor unit of the solar servo-control tracking device according to the embodiment of the present invention.

The solar servo-control tracking device according to an embodiment of the present invention, as illustrated inFIG. 1, includes an integrated control device having a single solar cell sensor unit300and an integrated control panel500, and plural solar tracking devices respectively having a tracking device controller70, a high torque driving unit20, a plurality of solar module assemblies10, and an operating angle sensor unit50(SeeFIG. 5).

The solar cell sensor unit300of the integrated control device detects solar luminance with respect to a solar azimuth, and the integrated control panel500remotely transmits a control signal with respect to a maximal solar azimuth that is calculated by comparing a solar azimuth detected by the solar cell sensor unit300with a solar azimuth measured by an azimuth equation in real time to the tracking device controller70via a wireless communication.

The solar azimuth A may be obtained from the following azimuth equation by using time H and declination δ.

Each of the tracking device controllers70of the solar tracking devices (1 to N inFIG. 1) receives a control signal from the integrated control panel500with respect to the solar azimuth via a wireless line, the high torque driving units20are respectively installed in the tracking devices 1 to N to provide driving forces to the tracking devices 1 to N through AC single phase inductors21generating a driving torque by a servo-control of the tracking device controllers70in accordance with the control signal, each of the solar module assemblies10is driven by the high torque driving unit20to track the solar azimuth in accordance with the control signal, and each of the operating angle sensor units50is installed to the respective high torque driving units20to detect the operating angles of the solar module assemblies tracking the sun in accordance with the control signal.

In this case, the control signal from the integrated control panel500is an operating angle controlling signal to implement an operating angle servo-control of the solar module assemblies10of the solar tracking devices in accordance with the solar azimuth measured by the solar cell sensor unit300.

On the other hand, the integrated control panel500and each of the tracking device controllers70respectively include wireless communication modules, TCP/IP communication modules, RF communication modules or Bluetooth communication modules to enable an operator to remotely monitor operating states of the solar module assemblies10and the solar cell sensor unit300with respect to the solar azimuth through the wireless communication modules and to remotely control the integrated control panel500and the tracking device controllers70through the TCP/IP communication modules, the RF communication modules, or the Bluetooth communication modules when the solar module assemblies10and the solar cell sensor unit300malfunction and cannot track the sun in accordance with the solar azimuth. Thus, unlike the related art, it is not necessary for the operator to directly manipulate at the site in such a way as to make the solar module assemblies be horizontal when a typhoon is coming, to make the solar module assemblies be vertical when it snows, to check the solar module assemblies for maintenance, etc.

Each of the solar module assemblies10, as illustrated inFIG. 2, include 16 solar panels in a 4*4 matrix array with 20% more weight than the existing 12 solar panels to maximize photovoltaic power generation. A single solar tracking device includes six solar module assemblies1,2,3,4,5, and6respectively each with 16 solar panels (at least 6 solar module assemblies, that is, six or more solar module assemblies) such that the high torque driving unit20(FIG. 5) is installed between third and fourth solar module assemblies3and4, that is, in the middle of the six solar module assemblies to effectively drive the six solar module assemblies at once.

In order to maximize the photovoltaic power generation per unit area, the solar module assemblies1,2,3,4,5, and6with increased weight more than 20%, as illustrated inFIGS. 3 and 4, are supported by and fixed to a solar module assembly adjusting shaft7through which a driving torque is transmitted from the high torque driving unit20. The solar module assembly adjusting shaft7is supported by an A-shaped support9fixed on a concrete structure8on the ground for the steady support of the solar module assemblies.

FIG. 4is a side view of the solar tracking device inFIG. 3and shows that the solar module assemblies1to6may be driven in an operating angle of 30 degrees to 150 degrees. The solar module assemblies1to6are servo-controlled in the operating angle range of 30 degrees to 150 degrees by the tracking device controllers70. In this case, the operating angles are detected by the operating angle sensor units50respectively attached to sides of the high torque driving units20.

Unlike the related art, in order to drive the solar module assemblies that are 20% heavier, high torque driving units20are needed. Each of the high torque driving units20is installed at the middle of each of the solar module assemblies, and as illustrated inFIG. 5, includes an AC single phase inductor21, a cooling fan23, a primary reducer22, a secondary reducer35, and a third worm reducer25and30. A reference numeral36indicates a second reducer fixture.

The AC single phase inductors21are driven through the servo-control performed by the tracking device controllers70in accordance with the control signal from the integrated control panel500, and the cooling fans23are attached to the AC single phase inductors21to cool heat generated by the AC single phase inductors21. To each of the AC single phase inductors21, the primary reducer22, the secondary reducer35, and the third worm reducer25and30are sequentially connected such that a pinion25of the third reducer is connected to the secondary reducer35and a worm wheel30is connected to the pinion25in a sequential manner to generate maximal driving torque. The solar module assembly adjusting shaft7to which the solar module assembly is fixed is installed on the worm wheel30.

In order to fix the pinion25of the third worm reducer, a worm gear upper fixture24, a worm gear left fixture26, a worm gear right fixture27, a worm gear left cover28, and a worm gear right cover29, as illustrated inFIG. 5, are provided. The driving force of the pinion25of the third worm reducer is transmitted to the worm wheel30at a gear ratio of 55:1, and the worm wheel30is coupled with a power transmission rotary shaft31and a power transmission shaft33and is fixed thereto by fixing pins inserted into power transmission shaft fixing holes32.

As illustrated inFIGS. 6 and 7, the solar module assembly adjusting shaft7ofFIG. 2is coupled to the left attaching hole37and right attaching hole38of the power transmission shaft33to drive the solar module assembly. The high torque driving unit20is fixed to a base plate34.

The high torque driving unit20provides a driving force for an increased load and employs the AC single phase inductor21capable of generating a driving force without a switching mode power supply (SMPS) additionally required when the existing DC motor is employed so that power consumption can be minimized, costs can be reduced, and durability of the solar tracking device can be improved.

As illustrated inFIGS. 8 and 9, in order to perform the servo-control of rotation angle of the solar module assemblies, the operating angle sensor unit50, detecting an absolute operating angle of the solar module assembly, must be installed on the driving unit. The operating angle sensor unit50includes a sensor pinion51, a sensor worm wheel52, and an operating angle sensor59. The sensor pinion51is connected to the pinion25of the third worm reducer of the driving unit20, the sensor worm wheel52is connected to the sensor pinion51, and the operating angle sensor59is installed to the rotation shaft of the sensor worm wheel52. An operating angle detected by the operating angle sensor59is transmitted to the integrated control panel500via the tracking device controller70through a wireless communication link.

As such, the operating angle sensor unit50having the same gear ratio (55:1) as the power transmission shaft33of the driving unit20is coupled with the pinion25of the third worm reducer so that the operating angle of the solar module assembly can be detected as a continuous absolute angle.

In other words, since a gear ratio between the pinion25and the worm wheel30is 55:1, when a gear ratio between the sensor pinion51and the sensor worm wheel52is set to 55:1, an operating angle of the power transmission shaft33to which the solar module assemblies are coupled is exactly the same as that of the sensor worm wheel52. To this end, the sensor pinion51meshed with the pinion25will rotate smoothly due to a bearing53fixed to a left side of the pinion and a bearing54fixed to a right side of the pinion.

Referring toFIG. 8, the sensor pinion51transmits the gear ratio to the sensor worm wheel52, and the sensor worm wheel52rotates smoothly due to a bearing55fixed to the upper side of the worm wheel52and a bearing56fixed to the lower side of the worm wheel52as illustrated inFIG. 9. An operating angle sensor59capable of detecting 360 degrees is installed on a rotation shaft of the sensor worm wheel52to detect an absolute rotation angle.

The solar cell sensor unit300, as illustrated inFIGS. 10 and 11, includes a stepping motor320, a solar cell rotation shaft360, a rotation angle sensor330, a solar cell310, a base plate400having supports380and390, a case340, a transparent semi-spherical body410, and a water-proof connector420.

The stepping motor320provides rotary power in order to measure an incident angle of sunrays entering at a maximum luminance such that the solar cell310can scan luminance of 30 degrees to 150 degrees. The solar cell rotation shaft360transmits the rotary power of the stepping motor320. The rotation angle sensor330measures an azimuth with respect to the luminance of the sunrays. The solar cell310is installed to the solar cell rotation shaft360to measure the luminance of the sunrays. On the base plate400, a left support380and a right support390to which the stepping motor320, the solar cell rotation shaft360, and the rotation angle sensor330are installed. The case340is installed on the base plate400to enclose and protect the stepping motor320, the solar cell310, the solar cell rotation shaft360, and the rotation angle sensor330. The transparent semi-spherical body410is installed on the top of the case340to protect the components in the case from entering water and from moisture. The water-proof connector420is installed to the case340to connect an electric wire providing electric power, and wires to input the control signal from the integrated control panel500to the stepping motor320and to output a signal from the rotation angle sensor330. A reference numeral350indicates a bolt fixture attaching the case340to the base plate400.

FIG. 12is a schematic diagram illustrating a measurement of a solar azimuth performed by the integrated control panel,FIG. 13shows circuit diagrams of the integrated control panel,FIG. 14is a schematic diagram illustrating an operating angle servo-control of the solar module assembly of the solar servo-control tracking device according to the embodiment of the present invention, andFIG. 15is a circuit diagram illustrating a tracking device controller.

As illustrated inFIG. 12, the solar cell sensor unit300measures luminance of sunrays at a solar azimuth to detect a maximal solar azimuth of the sunrays entering at a maximal incident angle. A solar cell rotation control signal511of 30 degrees to 150 degrees is periodically input to the solar cell sensor unit300. A rotation angle calculator521compares a rotation angle signal580detected and amplified by a rotation angle sensor570with the solar cell rotation angle control signal511. An error of the solar cell rotation angle is compensated by a proportional-integral-derivative (PID) servo controller530and is applied to a stepping motor driver540. The stepping motor driver540drives the stepping motor550and in this case the rotation angle560is detected by the rotation angle sensor570to be fed back to the rotation angle calculator521. A rotation angle of a solar cell590fixed to the stepping motor550is controlled by the stepping motor550and continuously scans luminance600every rotation angle of the solar cell590so that maximal luminance of the sunrays with respect to the rotation angle can be detected.

FIG. 13shows circuit diagrams of the integrated control panel500detecting the maximal luminance as depicted inFIG. 12, and the integrated control panel500includes a manual/automatic mode switch SW1selected by an operator, a real time counter (DS1307) U5to which a period is set to measure the solar azimuth by time period in real time, a first buffer circuit U2to which a rotation angle of the solar cell sensor unit300is input through the manual/automatic mode switch selected by the operator, a second buffer circuit U3to which the luminance of sunrays, measured at the rotation angle by the solar cell sensor unit300by the selection of the manual/automatic mode switch, is input, a microcomputer U1receiving the rotation angles of the first and second buffer circuits and the luminance of sunrays to output a rotation angle control signal through Darlington transistors U7and U8to the solar cell sensor unit300and outputting an operating angle control signal with respect to a maximal solar azimuth calculated by comparing the solar azimuth with respect to the luminance of sunrays with a solar azimuth that is measured in real time in accordance with the period of the real time counter, a wireless communication module U9transmitting the operating angle control signal to the tracking device controllers70, a memory U6in which data of the phase current of the AC single phase and the operating angles of the solar module assemblies received from the tracking device controllers70through the wireless communication module U9are stored, and a TCP/IP communication module U11transmitting the phase current and operating angle data read and outputted from the memory U6by the microcomputer U1.

The integrated control panel500further includes a second switch as a horizontal position angle correction mode switch SW2correcting initial position angles of the solar module assemblies and a third switch as a time setting mode switch SW3for real time setting in addition to the first switch as the manual/automatic mode selecting switch SW1. Selecting signals of the first, second, and third switches attached to the outer side of the case are inputted to the microcomputer U1via a connector W2.

The horizontal position angle correction mode switch SW2is used to initially set horizontal angles of the solar module assemblies after the rotation angle sensor330is installed to the solar cell sensor unit300. In this case, the rotation angle sensor330has the same capacity as that of the operating angle sensor59of the operating angle sensor unit50to output absolutely same rotation angles with respect to displacement. That is, the rotation angle sensor330sets a solar cell rotation angle of the solar cell sensor unit300to be equal to an operating angle of the operating angle sensor unit50. The time setting mode switch SW3sets the time of the integrated control panel500in an initial state.

Signals of the first, second, and third switches, SW1, SW2and SW3, are supplied to the microcomputer U1through a pull-up resistor. AC electric power of 220V is inputted through the connector W1and is converted into smoothed DC power by means of a transformer TS1and bridge diodes U15. In order to supply electric power suitable for driving respective circuits, electric power of +15V DC and +5V DC is supplied to the stepping motor320and the microcomputer U1through a +15 VDC regulator U13and a +5 VDC regulator U14, respectively. The electric power is supplied to the wireless communication module U9and the TCP/IP communication module U11by a +3.6 VDC regulator U12.

In order to control the rotation angle of the stepping motor320, the microcomputer U1outputs the rotation angle control signal to the stepping motor320of the solar cell sensor unit300using the Darlington transistors U7and U8and connectors W6and W7. Moreover, an analog input signal is inputted to an analog-digital converter of the microcomputer U1to provide a function of measuring an environmental factor.

In other words, in order to detect the rotation angle of the solar cell as the analog input signal, the rotation angle sensor330is connected to the connector W3such that the first buffer circuit U2performs the signal processing of the rotation angle, the solar cell output signal as the analog input signal is supplied to the second buffer circuit U3via a connector W4such that the second buffer circuit U3performs a signal processing of luminance, and in order to protect the solar module assemblies from typhoon, an output signal of an anemometer as an analog input signal is supplied to the third buffer circuit U4via a connector W5such that the third buffer circuit U4performs signal processing of wind velocity. Moreover, an oscillator U16applies a clock signal to the microcomputer U1.

The wireless communication module receives an optimal solar azimuth, transmits the operating angle control signal and a control signal for maintaining the solar module assemblies in a horizontal state when a natural calamity such as a typhoon or a fire is generated, and receives the operating angle of the solar module assemblies and an operation state of the AC single phase inductor.

The wireless communication module U9is an RS232C module and is interfaced by the TCP/IP communication module U11and an interface IC U10. The RS232C, that is, the wireless communication module U9, is connected to the operator's computer via a connector W8such that the operator remotely monitors the operational state of the integrated control panel. The operator controls the integrated control panel500from a long distance using the TCP/IP communication module U11interfaced with the RS23C module U9and the interface IC U10.

The phase current of the AC single phase inductor and information on the operating angles of the solar module assemblies are stored in the memory U6such that data stored in the memory U6are read to be transmitted when the remote monitoring is performed.

FIG. 14is a schematic diagram illustrating an operating angle servo-control of the solar module assemblies, in order to control the operating angles of the six or more solar module assemblies. As illustrated in the drawing, each of the tracking device controllers70performs the operating angle servo-control, and an automatic mode and a manual mode are provided by the manual/automatic mode selector140.

The automatic mode is activated when the photovoltaic generation is performed, and in the automatic mode, the operation angle control signal110is received from the integrated control panel500to perform the operation angle servo-control of the solar module assemblies. The operating angle control signal110of the integrated control panel500and operating angle output signals220of the solar module assemblies detected and amplified by the operating angle sensor210are compared by the operating angle processor120such that error of the operating angle of the solar module assemblies is compensated by a proportional-integral-derivative control performed by a PID servo-controller130and is supplied to an AC single phase inductor driver150by the manual/automatic mode selector140to drive the AC single phase inductor170and an operating angle200for driving the solar module assemblies is outputted through a contact B of a relay180. In this case, the phase current of the AC single phase inductor170is detected by a current sensor160to be compared with a reference phase current230. When the phase current is greater than the reference phase current, the relay180is switched from the contact B to a contact A to interrupt the electric power supplied to the AC single phase inductor170driving the solar module assemblies.

The manual mode is used when maintenance of the solar tracking device is performed and is selected by the operator manipulating the manual/automatic mode selector140to open the operating angles of the solar module assemblies. The manual/automatic mode selector140is switched to the manual mode such that a driving command is supplied to the AC single phase inductor driver150to drive the AC single phase inductor170and to control the output of the operation angles of the solar module assemblies.

FIG. 15is a circuit diagram illustrating the tracking device controllers that implement the operation angle servo-control. Each of the tracking device controllers includes: a manual/automatic mode switch S1selected by an operator; a buffer circuit J2to which the operating angle of the solar module assembly detected by the operating angle sensor unit is inputted when the automatic mode of the manual/automatic mode switch S1is selected by the operator; wireless communication modules J5and J6which receive an operating angle control signal remotely transmitted by the integrated control panel; a microcomputer J1having a memory storing the operating angle and the phase current of the AC single phase inductor and outputting a servo-control signal for the PID servo-control of the solar module assembly to the AC single phase inductor of the high torque driving unit20, through a forward relay K1and a reverse relay K2in accordance with a value calculated from the operating angle inputted through the buffer circuit J2and the operating angle control signal inputted through the wireless communication modules J5and J6, to control the operating angle of the solar module assembly; and an RF communication module or a Bluetooth communication module J7remotely transmitting data on the operating angle and the phase current of the AC single phase inductor stored in the memory.

In addition to the first switch, the manual/automatic mode switch S1, there is a second switch, the horizontal position angle correction mode switch S2correcting an initial position angle of the solar module assembly, and a third switch, the time setting mode switch S3for real time setting. Selection signals of the first, second, and third switches attached to the outer side of the case are inputted to the microcomputer J1through a connector P5.

The horizontal position angle correction mode switch S2is used to initially set a horizontal angle of the solar module assembly after the operating angle sensor59of the solar module assembly is installed to the high torque driving unit20. The time setting mode switch S3sets time of the tracking device controller70in an initial state.

Signals of the first, second, and third switches S1, S2, and S3are supplied to the forward relay K1and the reverse relay K2via the connector P1, to be connected to the AC single phase inductor through the connector P4. In addition, a relay driving IC J4is used to excite the relays.

AC electric power of 220V is converted into smoothed DC power by means of a transformer TS2and bridge diodes J11. Electric power of +15V DC and +5V DC are supplied to the buffer circuit J2and the microcomputer J1through a +15 VDC regulator J8and a +5 VDC regulator J9, respectively. The electric power is supplied to the wireless communication modules J5and J6and the RF communication module or the Bluetooth communication module J7by a +3.6 VDC regulator J10.

The wireless communication modules J5and J6include an RS232C module J5and an RS232C module J6and are interfaced with the RF communication module or the Bluetooth communication module J7and an interface IC J13. The RS232C modules J5and J6, the wireless communication modules, are connected to an operator's computer via a connector P2such that the operator remotely monitors the operational state of the tracking device controller. The operator controls the tracking device controller70from a distance using the RF communication module or the Bluetooth communication module J7interfaced with the RS23C modules J5and J6and the interface IC J13.

When the AC single phase inductor170is continuously operated due to malfunction of the solar module assembly, a signal inputted through a current sensor connector P3is used by the buffer circuit J2to detect the phase current of the AC single phase inductor170and to compare an operating time with the reference phase current to determine whether the solar module assembly has malfunctioned.

On the other hand, in order to verify the precision and reliability of the operating angle control signal remotely received and inputted from the integrated control panel500through the wireless communication modules J5and J6, the tracking device controller70includes a real time counter (DS1307) J3by which a period for measuring the solar azimuth by time period in real time can be measured.

The microcomputer U1of the integrated control panel500remotely outputs the operating angle control signal (with respect to the maximal solar azimuth) and the maximal solar azimuth to the tracking device controllers70through the wireless communication module U9. Each of the microcomputers J1of the tracking device controllers70compares the maximal solar azimuth remotely received through the wireless communication modules J5and J6with the solar azimuth calculated by a real time azimuth equation using the real time counter (DS1307) J3and outputs only the verified operating angle control signal to the AC single phase inductors21of the high torque driving units20.

FIG. 16is a flowchart illustrating the control performed by the integrated control panel and the tracking device controllers.FIG. 17is a view illustrating response characteristics of the solar cell sensor unit with respect to the solar azimuth where X-axis represents a solar azimuth and Y-axis represents luminance measured by the solar cell sensor unit, andFIG. 18is a view illustrating a time response operation characteristic of the solar module assembly where X-axis represents time and Y-axis represents a driving angle of the solar module assembly.

FIG. 16shows a control program implementing remote control and remote monitoring smoothly performed between the integrated control panel500and the tracking device controllers70. As illustrated in the drawing, the integrated control panel500measures the luminance of sunrays in a range of 30 degrees to 150 degrees through the solar cell sensor unit300(800), analyses the measured luminance of sunrays with respect to the operating angle detected by the operating angle sensor units50to set an operation angle range of the maximal luminance (810), and compares the solar azimuth calculated by the azimuth equation (820) with the operating angle range of the maximal luminance (830) to calculate the operating angle control signal for the solar module assemblies (850) and to transmit the operating angle control signal to the tracking device controllers70through the wireless communication module via a wireless link (860).

On the other hand, the integrated control panel500receives the operating angles of the solar module assemblies and the measured phase currents of the AC single phase inductors from the tracking device controllers70via a wireless link (840) to transmit the operating angle control signals to the solar module assemblies to track sun rays in accordance with the operating angle control signals, or to transmit control signals to the tracking device controllers70to stop the solar module assemblies when the AC single phase inductors are in an over-current state.

Each of the tracking device controllers70receives the operating angle control signal from the integrated control panel500(900) to calculate an error of the operating angle measured by the operating angle sensor unit50, performs the compensation by the PID servo-control using the calculation (910) to drive the AC single phase inductor (920) so as to drive the solar module assembly (930), and in this case measures the phase current of the AC single phase inductor (940) and the operating angle of the solar module assembly to implement the servo-position angle control. When the solar module assembly malfunctions in being unable to track in accordance with the operating angle control signal (950), the tracking device controller70transmits the operating angle of the solar module assembly and the phase current signal of the AC single phase inductor to the integrated control panel via a wireless link (960). The operator can check by remote monitoring through the TCP/IP communication module whether the solar tracking device malfunctions and can take emergency measures.

FIG. 17is a view illustrating a characteristic curve of luminance continuously determined in relation to the solar azimuth in a range of 24.3 degrees to 153 degrees by the solar cell sensor unit300. For example, when a solar azimuth of 72.3 degrees at the maximal luminance is detected, the integrated control panel500transmits the operating angle control signal to the multiple tracking device controllers70of the solar tracking devices. The solar cell sensor unit300can detect the optimal solar azimuth as in the characteristic curve.

FIG. 18is a view illustrating a time response operation characteristic of the solar module assemblies when the operating angle control signal of 30 degrees to 90 degrees is applied at the initial position. Therefore, it can be confirmed that a precise operating angle servo-control is implemented using the operating angle sensor unit50. As known from this result, each of the tracking device controllers70receives the optimal operating angle control signal from the integrated control panel500to precisely perform the operating angle servo-control so that efficiency of photovoltaic power generation can be improved by 5% to 10%.