TECHNICAL FIELD

The present disclosure relates generally to LED lighting systems. More particularly the disclosure relates to a system that detects failure of a particular LED panel and provides appropriate feedback.

BACKGROUND

Currently, the world is ever demanding and expectation of high performance from every product is common. The existing technology does not use LED based lighting system which can reduce the power consumption to a large extent and it does not have any means of failure detection and feedback system.

In places where there are huge installations of lighting; monitoring the performance, detection of faulty lights and replacement of the same are some commonly seen problems. Also, in general for most of components of the lighting fixtures as well as drivers performance drops due to ageing. Further, most likely failing components have been identified which are used in the LED drivers and in few cases the LED tails fails as well. There is a need for a system which monitors, detects failure and provides feedback.
Hence, the present disclosure is developed to overcome the above mentioned issues.

SUMMARY

The shortcomings of the prior art are overcome and additional advantages are provided through the provision of a method and system as described in the description.
The present disclosure solves the limitations of background by providing a system and a method for detecting fault or failures of a particular LED panel and providing appropriate feedback. On detection of a particular fault the system shall send a Short Message Service (SMS) via the GSM (Global System for Mobile Communications) module to the service engineer. The SMS contain the information of what kind of fault or failure and the location where the fixture is placed. The system uses a protocol and hardware for communication between GSM module and fixtures that optimizes the cost to a large extent. A level of intelligence is added that could accurately detect different kinds of faults.

In one embodiment, the system to detect a failure in a lighting fixture comprises of at least one lighting fixture, each lighting fixture consist of a plurality of tiles, each tile consists of plurality of light emitting diodes (LED), each tile is connected with a predetermined sensor to sense current flowing through the LEDs. A driver circuit to drive each tile, said driver circuit is connected with plurality of sensors to sense the current flowing into and out of the driver circuit. A microcontroller is interfaced with the lighting fixtures to receive values sensed by the sensors. The microcontroller consists of a look-up table with predetermined values of each lighting fixture to compare the sensed values periodically. The look-up table also consists of each lighting fixture location. A GSM module is interface with the microcontroller to receive a fault signal from the microcontroller and to generate a preconfigured message about the failure. The fault signal is generated by the microcontroller if the compared value exceeds a predefined threshold value

BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES

The novel features and characteristics of the disclosure are set forth in the appended claims. The embodiments of the disclosure itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures in which:

Figure 1 illustrates the block diagram of GSM based failure feedback system for lighting
fixtures.

Figure 2 illustrates LED lighting fixture.

Figure 3 illustrates the LED lighting tile structure, as one embodiment.

Figure 4 illustrates LED driver circuit interface with the microcontroller using sensors, as
one embodiment.

Figure 5 illustrates a connection of all the lighting fixtures to a single GSM module.
The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative
embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION

The foregoing has broadly outlined the features and technical advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter which form the subject of the claims of the disclosure. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the disclosure as set forth in the appended claims. The novel features which are believed to be characteristic of the disclosure, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of Figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure.

Exemplary embodiments of the present disclosure provide a method and a system for GSM based failure feedback system for LED's lighting fixtures.

In one embodiment, the disclosure provides an inexpensive mode of monitoring degradation in performance, failure and notification of the same to a service engineer for replacement or repair. The disclosure aims at providing an optimized inexpensive solution to the customers. The innovation lies in the estimation of the kind of fault based on the various measured parameters. The fixture also houses backup batters to make sure the system runs reliably. On detection of a particular fault the system shall send a Short Message Service (SMS) via the GSM (Global System for Mobile Communications) module to the service engineer. The SMS contain the information of what kind of fault or failure and the location where the fixture is placed. The disclosure uses a specifically
developed protocol and hardware for communication between GSM module and fixtures that optimizes the cost to a large extent. A level of intelligence is added that could accurately detect different kinds of faults.

In one embodiment the disclosure uses light emitting diode (LED) lighting fixture with 4 LED tiles. The LED tiles provide the flexibility in redesigning the LED lighting fixture as required depending on the power consumption and the required LUX output. The LED lighting fixtures has a good life only when maintained at a constant current. A special driver is using the latest SMPS based technology is used to shrink the size and improve the performance as compared to conventional drivers. As all devices and components these fixtures and drives performance drops due to ageing. Also, few common problems and most likely failing components have been identified which are used in the LED drivers. Also in few cases it was observed that sometimes the LED tails fails as well. The disclosure implants sensors in critical areas and monitor the same. This could increase the cost of the product. The challenge is to implement the same with the least possible cost.

Also the produce demanded for a simple protocol for communication between GSM module and micro-controller. Also to provide more reliability some level of intelligence is added into the system.

Figure 1 illustrates the system block diagram. The system has a LED light fixture which is made of housing and 4 LED tiles as shown in the figure 1. The LED tile structure provides flexibility to modify the LUX output and power consumption as required. This also reduces TTM for a given product and helps in fast customizing as required by the customer. Each tile contains a series parallel combination of LED which makes sure that a single LED failure does not lead to the failure of the entire tile.

The tiles are powered from a SMPS based driver. The driver has a feedback making sure there is a constant current flowing through the tile. In case some of the LED's fail in one of the tail the current in the rest of the tails increases. This property is observed closely to identify any kind of fault in the led tiles. A standard 2x2 LED light fixture contains 4 LED tiles in a 2x2 fashion as shown in figure 2.

The LED tile is made of a about 120 LEDs in a series parallel combination circuit (30 in parallel making a string and 4 such strings in series) as shown in Figure 3. This combination ensures that even if one LED fails it does not affect the entire tile. But it is seen that if one of the LED fails, the overall current flowing in all the other tiles increases. Though it is rare but once an entire tile fails there is a 33.3% of increase in current seen in rest of the tiles. The entire system is designed to work with a about 14 V and this combination consumes approximately 2.4 Ampere of current which means that each tile consumes approximately 600mA of current.

In one embodiment of the disclosure, current sensors placed at the input of each tile of the LED lighting fixture and the output of it is fed to a microcontroller. Overall there are four current sensors measuring the current flowing in each tile. The crucial points which can be classified as fault and these values are stored in a lookup table in a microcontroller. Once this point reaches the microcontroller will automatically send an SMS to the service engineer indicating which LED tile has failed or if a considerable number of LED's have failed in a single tile.

Also, failures of LEDs in the LED lighting fixture have very less probability and the components in the driver are more prone to failure. There are few commonly observed faults in a driver such as failure of current feedback resistor due to short circuit in the output and fuse failure due to surges at input. The voltage across fuse and the voltage across the feedback sensor both are monitored periodically and once it crosses the predefined values appropriate messages will be sent through a GSM module. The figure 4 illustrates the monitoring of LED driver circuit using by the microcontroller using the current sensors.

The system as shown in the figures 1 and 5 a 20mQ resistor is used as a current sensor and 2.4A of current flows through it. Hence, the voltage across the current sensor is about 0.048V. As this voltage is very small an amplifier is designed to get a voltage range between 0 to 5V and then it is then fed to a controller. Under normal working conditions there is some amount of voltage seen across this resistor and once it fails the voltage drops to 0V indicating a short circuit in the output of the driver.

Also, a fuse is provided at the input of the driver which protects the driver from surges. During surges this fuse fails protecting the driver. The fuse is again monitored and the signal is sent to a controller or a control unit. Depending on its values appropriate messages shall be sent. It is to be noted that in either case of the faults the fixture fails to work and it shall take some time to test the same and rectify. But with the features provided here the preliminary diagnosis is already done and a report indicating the problem which shall reduce the time of service to a large extent.

The controller used in the system is an inexpensive low power microcontroller. The microcontroller does a routine check throughout the day and the readings are saved in its memory. One could get the readings by sending an SMS to this system, on the other hand if any kind of fault occurs it shall automatically send a message containing the information about what the fault is and the location of the light fixture. In case, the microcontrollers finds differed readings not matching with any default values in the memory/database the microcontroller shall send the same to a service engineer asking what kind of a fault it is and once it gets a message from the service engineer it will log the same as a new fault. This is an iterative method which learns and becomes more robust as it ages. One of these boards is attached with each fixture and a group of lights report to a single GSM module. This configuration reduces the cost of the entire system considerably and makes it more reliable.

Figure 5 shows the system architecture as one embodiment in which all the lighting fixtures are connected to a controller module which is in turn connected to the GSM module. This architecture is followed so that only one GMS module would be sufficient for a number of fixtures.

Each lighting fixture is connected with a microcontroller board which does the diagnosis and takes appropriate actions. The main parts of the microcontroller board are a power supply circuit, microcontroller, communication interface circuit, sensor interface circuit, power on indicator and booting indicator, which is as shown in the figure 5. The microcontroller is a low power device running at a low voltage (about 3.3V). To get the

required voltage a 5V regulator is used to first step down the driver output voltage from I4V to 5V. This is then regulated to 3.3V using a predefined regulator. The microcontroller was selected based on the required peripherals. A low cost robust microcontroller, PIC18F2520 is used in one embodiment. It has 32KB of programmable memory which was much required for creating the look-up table having all kinds of faults and the parameter values that indicate the values. The system also ensures it has enough place so it can extend its look up table on the run.

As shown in the figure 5, the system architecture uses a single GSM module and a number of light fixtures are connected to a single GSM module. For example one single GSM module can be used for an entire floor of light installments. As the distance may vary and would always be more that a meter TTL logic level for communication cannot be used. So we use RS485 physical layer with a customized protocol to communicate the information over long distances.

The selected microcontroller has an inbuilt ADC and the sensors can be directly interfaced to the same. It has 6 channels ADC which was the exact requirement. There are few indicator LED provided to know the working status of the board.

The present disclosure is not to be limited in terms of the particular embodiments described in this application, which are intended as illustrations of various aspects. Many modifications and variations can be made without departing from its spirit and scope, as will be apparent to those skilled in the art. Functionally equivalent methods and devices within the scope of the disclosure, in addition to those enumerated herein, will be apparent to those skilled in the art from the foregoing descriptions. Such modifications and variations are intended to fall within the scope of the appended claims. The present disclosure is to be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.

With respect to the use of any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.

In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.
While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

We claim:

1. A system to detect a failure in a lighting fixture comprising of:
at least one lighting fixture, each lighting fixture consist of a plurality of tiles, each tile consists of plurality of light emitting diodes (LED), each tile is connected with a predetermined sensor to sense current flowing through the LEDs; and a driver circuit to drive each tile, said driver circuit is connected with plurality of sensors to sense the current flowing into and out of the driver circuit;
a microcontroller interfaced with the lighting fixtures to receive values sensed by the sensors, said microcontroller consists of a look-up table with predetermined values of each lighting fixture to compare the sensed values periodically, said look-up table also consists of each lighting fixture location; and
GSM module receives a fault signal from the microcontroller to generate a preconfigured message about the failure, said fault signal is generated by the microcontroller if the compared value exceeds a predefined threshold value.

2. The system as claimed in claim 1, wherein a switched-mode power supply (SMPS) power supply provides power to the lighting fixture and the microcontroller.

3. The system as claimed in claim 1, wherein the predetermined sensor is a current sensor.

4. The system as claimed in claim 1, wherein the preconfigured message generated by the GSM module is a Short Message Service (SMS).

5. The system as claimed in claim 1, wherein the driver circuit is provided with a fuse to protect said driver circuit from current surges.

6. The system as claimed in claims 1 and 6, wherein the sensors of the driver circuit monitor the current through the fuse.

7. The system as claimed in claim 1, wherein the microcontroller is provided with an artificial intelligence module to generate a fault signal if the sensed value by the sensors do not match with the values in the look-up table.

8. The system as claimed in claim 1, wherein the preconfigured message generated by the GSM modules consists of the location of the lighting fixture and the fault message.

9. A method for detecting of failure in a lighting system comprises acts of:
sensing current values periodically using predetermined sensors;
comparing the sensed current values with predefined values stored in a look-up table of a microcontroller;
generating a fault signal if the compared value exceeds a predefined threshold value by the microcontroller; and
generating a preconfigured message about the failure by the GSM module.

10. The method as claimed in claim 9, wherein the predefined threshold value stored in the look-up table are the current values of the lighting fixtures under normal operating conditions without any failures.

11. The method as claimed in claim 9, wherein the preconfigured message generated by the GSM modules consists of the location of the lighting fixture and the fault message.