SOLAR PANEL ALIGNMENT APPARATUS

FIELD OF THE INVENTION

This invention relates to an apparatus to facilitate the installation and directional alignment of a solar panel.

BACKGROUND OF THE INVENTION

For solar powered applications, it is preferable that the solar panels be aligned at installation for maximum sun exposure. It is therefore known to install rotating or tracking solar panels, in order to enable the cells to follow the sun as it moves across the sky. This maximizes the cell's exposure to sunlight throughout the day. Examples of solar tracking arrangements include U.S. Patent Nos. 4,625,709; 6,960,717 and 6,680,693.

The costs associated with installation and maintenance of these relatively complex systems can be prohibitive. The equipment associated with the tracking system can be heavy and cumbersome to deal with, and can be very expensive to transport to remote locations. If the tracking system is motorized, it can consume a portion of the power meant to be collected by the photovoltaic cells. In situations where smaller, simpler lights or lighting systems are required, such as in arrays of fixed solar- powered lights, such tracking technology is unnecessarily costly.

It is therefore preferable in some situations to fix the solar panels in an orientation designed to maximize the degree of sun exposure without tracking the movement of the sun. In the northern hemisphere, this generally means directing the solar panels towards true South, while true North is the preferred orientation in the southern hemisphere. Installations comprising several solar panels are also more visually appealing if they are correctly aligned and facing in the same direction. Directional alignment of various other devices has been achieved by linking to a feedback signal whereby the alignment is confirmed by reaction to the strength of the signal. U.S. Patent Nos. 6,795,033 and 6,683,581 describe methods to align the antenna associated with a satellite dish with the desired satellite. U.S. Patent Nos. 6,937,188 and 7,432,868 each disclose a portable apparatus by which an antenna may be adjusted in order to achieve maximum signal strength from a satellite. However, where the goal is simply to align a solar panel in a fixed optimal direction having regard to the sun's path through the sky over the day and through the year, there is no signal strength on which to base an immediate feedback mechanism.

It can be very difficult for an installer to accurately and consistently achieve proper alignment by simply "eyeballing" true North or true South. The resulting misalignment represents losses in solar power. It is known for installers to use a manual compass, sitting on or otherwise attached to the solar panel support, to assist in the alignment process. In this situation, it can be difficult to properly align the solar panel direction with the compass and it can be very difficult to physically manipulate the solar panel, which often requires two hands, while also handling and verifying the readings from the manual compass, especially if the panel is being mounted overhead or at arm's length from the installer. In situations where a solar panel is located in an elevated spot, such as on top of a pole, in order to ensure that it is free of obstructions from nearby trees and other structures, these issues are even more complex. In such circumstances, the installer is often working from a ladder or a mobile bucket, decreasing his physical mobility and compromising his manual dexterity and personal safety. All of these factors further increase the time and cost of the initial installation, and of any maintenance visits.

In addition, a manual compass, by its nature, finds magnetic North and South. An installer is therefore required to either know how many degrees true North or South deviates from magnetic North or South at the installation location and to compensate accordingly, or to accept that degree of misalignment and corresponding lack of efficiency from the solar panel. It is therefore the object of the present invention to simplify the alignment process for an installer, making the process repeatable and accessible even if the installer cannot freely use both hands or cannot freely move around the solar panel.

This and other objects of the invention will be better understood by reference to the detailed description of the preferred embodiment which follows. Note that not all of the objects are necessarily met by all embodiments of the invention described below or by the invention defined by each of the claims.

SUMMARY OF THE INVENTION

According to one aspect of the invention, a solar unit includes a solar panel and a digital compass that is fixable in relation to the solar panel. Feedback means of some sort provide feedback to the installer indicative of how closely aligned the solar panel is with a predetermined desired heading, for example true North or true South.

In a more particular aspect of the invention, the feedback comprises an audible repeating tone whose intervals are indicative of proximity to the desired heading.

In a further aspect, the solar unit includes a solar-powered light source and the feedback consists of strobing the light with the frequency of the strobe being indicative of proximity to the desired heading.

In another aspect of the invention, a processing unit in the solar unit, or alternatively the digital compass itself, compensates for the declination or variation between magnetic North or South and true North or South based on GPS coordinates and a reference table. The GPS receiver is preferably included in the solar unit.

In a further aspect, a processor stores a predetermined desired heading and a reference table of declinations (for at least one location). The processor establishes a correction for the declination, compares the sensed magnetic heading with the predetermined desired hearing, and controls the feedback. In yet another aspect of the invention, the solar unit comprises means to detect manual tapping of the housing of the solar unit and to recognize a predetermined tap pattern to activate an alignment or orientation configuration mode for the solar unit.

The foregoing was intended as a broad summary only and of only some of the aspects of the invention. It was not intended to define the limits or requirements of the invention. Other aspects of the invention will be appreciated by reference to the detailed description of the preferred embodiment and to the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described by reference to the detailed description of the preferred embodiment and to the drawings thereof in which:

Fig. 1 is a perspective view of the preferred embodiment of a solar unit according to the invention;

Fig. 2 is a schematic of the alignment components of the preferred embodiment, which would typically be within the housing of the solar unit;

Fig. 3a is a perspective view of a solar unit adapted for an alternative embodiment of the invention;

Fig. 3b is a perspective view of the solar unit of Fig. 3a with a removable alignment module attachable to a mounting mechanism on the housing in accordance with an alternative embodiment of the invention;

Fig. 4 is a perspective view of a solar unit adapted for an alternative embodiment of the invention; and

Fig. 5 is a perspective view of a solar unit adapted for an alternative embodiment of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to Fig. 1 , the preferred embodiment is a solar unit 10 that includes a housing 12 for a solar engine, a solar panel 14 and a post 16 for mounting the housing 12 and the solar panel 14.

For optimal energy absorption, solar panel 14 should be aligned with a preferred heading A. For most installations in the northern or southern hemispheres, preferred heading A will be true South or true North respectively.

As shown in Fig. 2, the components preferably contained within housing 12 (not shown) include a battery, power management circuitry, and a microcontroller 18 for controlling various power management, user settings and other functions of the solar unit. As discussed below, microcontroller 18 is also used to detect an installer request to enter the alignment configuration mode, to detect and calculate the actual heading of the solar panel and to control feedback to the installer. In the preferred embodiment, an MSP-430 series processor from Texas Instruments® is used because of its low power consumption, but any suitable microcontroller may be used.

Housing 12 also preferably includes a GPS module 20, a digital compass 22 and a shock sensor 24, each of whose outputs is directed to the microcontroller 18.

The GPS module 20 may be any suitable GPS device, such as the GPS2058 from DeLorme®, which supplies date, longitude, latitude and altitude to the microcontroller 18. In the case where the ultimate destination of the solar unit 10 is not programmed at the factory, the latitude information enables the unit to determine whether true North or true South will be the default predetermined desired heading.

Digital compass 22 can be realized in a number of ways, including the use of a plurality of single-axis sensors, a dual axis sensor or a three-axis sensor. In the preferred embodiment, a two-axis Hall sensor is used. The magnetic direction can be determined by reference to the outputs of the two magnetic sensors, provided the sensor is flat as compared to the surface of the Earth. In some applications, the solar unit housing 12 will be designed to be mounted on a properly vertical support in which case the two-axis sensor 22's attitude to the horizontal within the housing 12 can be reliably estimated for manufacturing purposes. In cases where the supplier of the solar unit 10 cannot predict the final orientation and attitude of the housing 12, a three-axis sensor or two two-axis sensors is preferred.

Digital compass 22 is fixed within housing 12 so as to align its reference heading with heading B of the solar panel 14.

A database 26 contains a reference table with magnetic declination data drawn from a suitable source, such as the International Geomagnetic Reference Field series of models. The data and method of calculating true heading based on the magnetic heading and a known location is widely available for reference. For example, the National Geophysical Data Center has the information and updates at http://www.ngdc.noaa.gov.

In the case where the installation location of the solar unit 10 is known to the manufacturer, the microcontroller 18 can be pre-programmed for the amount of declination to apply to the magnetic bearing. Alternatively, where a GPS module 20 is not incorporated into the solar unit, the location of the solar unit 10 can be programmed into the solar unit 10 through an appropriate user interface.

In yet another alternative, the GPS module 20 may still be incorporated into the solar unit 10, but database 26 is not. In such a case, the installer may manually enter a magnetic declination for the solar unit 10 prior to beginning the installation and alignment process.

In yet a further alternative, solar unit 10 may be provided with wireless capability, enabling it to receive location and declination information wirelessly, for example from another solar unit in an array of solar units. This capability may also be included in separate removable alignment modules, in order to allow the module to compensate for changes in the location of true North or true South over time.

Shock sensor 24 may be for example the SQ-ASB-010 from Signalquest, Inc. which comprises normally closed acceleration switches. Alternatively the SQ-SEN-200 series omnidirectional tilt and vibration sensors can be used. The shock sensor 24 enables the detection of an impact to the housing 12, such as the installer rapping or tapping the side of the housing 12. Preferably, the shock sensor 24 is mounted directly or indirectly on an exterior wall of the housing 12 and a sign or other appropriate markings on the exterior of the housing 12 indicates to the installer where to tap the housing when he wishes the solar unit 10 to enter into the alignment configuration mode.

To begin the alignment procedure, the installer raps on or taps a designated area on the wall of the housing 2 behind which the shock sensor 24 is attached to the wall, either directly or indirectly, such as through a mounting or circuit board containing the shock sensor 24 that is attached to the wall. Shock sensor 24 reacts to the shocks caused by the rap or taps, and the microcontroller 18 analyzes the output of the sensor 24.

Preferably, microcontroller 18 only determines an intentional triggering of the alignment configuration mode when the sensor 24 detects a specified number of consecutive taps within a predetermined time frame, such as two taps within one second. Microcontroller 18 is further programmed to validate only those inputs that indicate a range between a minimum and a maximum threshold, such that light taps, wind gusts or solid bumps will not activate the alignment configuration mode.

In the alignment configuration mode, the microcontroller 18 causes an audible signal to be generated by a tone generator 28, thereby signalling to the installer that the alignment feedback process will begin. In order to avoid wasting power in the case of false starts, microcontroller 18 is programmed to exit the alignment configuration mode if no changes in the solar panel 14 bearing B are detected by the digital compass 22 within a predetermined time, such as 30 seconds. Upon exiting the configuration mode, the tone generator 28 emits another audible tone or tones indicative of shut down.

Microcontroller 18 receives the readings from compass 22, indicating the changing bearing B of the solar panel 14 as it is moved towards desired heading A. Microcontroller 18 then begins emitting tones through tone generator 28. As the solar panel bearing B approaches heading A, the frequency of the tones emitted will increase. Eventually, as the solar panel bearing B converges with heading A, a steady tone will be emitted, signalling that alignment is complete.

In order to exit the alignment mode prior to the default inactivity period for exiting that mode, a simple log-off procedure, such as another series of taps, may be employed.

Thus, the invention enables the installer to quickly and positively align the solar panel in the optimal position for sun exposure, with much less uncertainty and room for error than would be the case with a manual compass or a visual approximation of the solar panel position. Further, the operator is free to use his hands to orient the solar panel, rather than fidgeting with a manual compass or other parts of the solar panel.

In the alternative embodiments illustrated in Figs. 3a and 3b, the operational components of the alignment system (microcontroller, digital compass, shock sensor, tone generator, GPS module and associated power source) may be provided as a separate removably attachable module for use with a plurality of solar units. This has the potential of reducing costs and space requirements in some solar units, for example in the case of a large array of small solar-powered lights.

Referring to Fig. 3a, housing 40 is provided with a mounting mechanism 42 for removably attaching a separate alignment module 44 in a fixed relative position and orientation in relation to the housing 40. Mounting mechanism 42 may be of any suitable configuration to connect to a corresponding portion of the removable alignment module, such as a sleeve, pin, clasp, clamp, plug, bracket or receptacle to provide a mating reference portion of the housing 40. Removable module 44 includes a shock sensor 46 that detects tapping on the module 44. The operation of the removable module embodiment is otherwise similar to the preferred embodiment with minor modifications as may be suitable. In an alternative embodiment, best shown in Fig, 3b, mounting mechanism 42 may be mounted on an inner surface of a panel 62 in housing 12 which is opened by the installer, such that opening up panel 62 provides a surface of known orientation, such as horizontal, on which to mount removable module 44. In a further alternative embodiment, best shown in Fig. 4, the solar unit 10 powers a beacon or light separately 48A or integrally 48B associated with the unit 10. Flashing of the light 48A or 48B is substituted for the generation of audible tones, thereby taking advantage of the inherent features of the unit. The light 48A or 48B may be made to flash at an increasing frequency as the bearing B of the solar panel 14 converges with the predetermined desired heading A. Eventually, as the bearing B of solar panel 14 approaches heading A, the frequency of the flashes increases until a steady light is emitted once the desired heading is reached.

It will be understood that the embodiment shown in Fig. 4 may alternatively include a removable alignment module, as in the embodiments shown in Figs. 3a and 3b, incorporating a beacon or light as a visual feedback mechanism.

The feedback mechanism is not limited to audible tones and lights. Vibration or other tactile feedback is also contemplated, as is wireless signalling to the installer.

In yet a further alternative embodiment, best shown in Fig. 5, the solar unit 10 is provided with the capability for the installer to manually adjust not only the direction of the solar panel 14, but also its angle to the horizontal. By including an inclinometer 50 in the housing 12 and feeding its output to the microcontroller 18, a user feedback can be provided as to the angle (to the horizontal) that the panel 14 is in at any given time. Such user feedback can produce an audible sound, for example reciting the degrees of inclination. The inclinometer information can be calculated from the output of a 3-axis sensor, such as that commonly used in cellular phones.

An inclinometer 60 may be attached to the post 16 that supports the solar unit 10, or to the housing 12 that contains the digital compass 22 (not shown) to provide user feedback informing the installer when the entire unit 10 is in the desired vertical orientation. This facilitates reliable readings of the digital compass 22 for alignment purposes particularly if a single two-axis digital compass is used that requires its attitude to be flat in relation to the surface of the Earth. In difficult terrain, correct vertical positioning of the entire solar unit 10 may not be easy without assistance. In both of the foregoing embodiments, the panel inclination configuration mode and the solar unit vertical alignment mode, the alignment feedback mechanism is triggered substantially in the same way as previously described, namely by rapping or tapping on the side of the housing 12 or module 44. Such embodiments preferably further contemplate a menu approach to select between the panel inclination configuration, solar unit vertical alignment and panel heading configuration modes.

It will be understood that the embodiment shown in Fig. 5 may alternatively comprise a separate removable alignment module, as in the embodiments shown in Figs. 3a and 3b, through which the panel heading configuration may be carried out.

It will be appreciated by those skilled in the art that the preferred and alternative embodiments have been described in some detail but that other modifications may be practiced without departing from the principles of the invention.