kata kunci: LED lighting, energy measurement, ambient light sensing, sensors, G3-PLC, powerline communication, LED driver, efficiency, energy, power savings, DALI

  

APPLICATION NOTE 5383

Adding Intelligence to LED Lighting By:  David Andeen, Director of Applications, Maxim Integrated

Abstract: How smart is your LED lighting system? While LED lighting holds the promise of reducing energy consumption and maintenance costs, smart LED lighting designs improve system performance in both areas, achieving higher performance per watt and reducing cost in the long term. Energy measurement, ambient light sensing, and communication serve as the cornerstones of smart LED lighting design. Energy measurement provides system health and consumption information. Ambient light sensing reduces an LED's on-time, conserving energy and extending diode lifetime. Communication links together each luminaire for identification of maintenance and system level coordination. The contribution of components to the overall system performance will be explored. 

A similar version of this article appears on EDN, June 12, 2012.

Introduction

Imagine a marathon on a very hot, dusty day when saving every ounce of energy matters to the outcome. This race isn't half over, but the winner seems certain. The lead looks insurmountable, because this runner can do more with less energy. This runner shines brighter. In the face of heat and competition, this runner stays cool. So far, so good. Yet, will this competitor set the pace and hold the lead in the second half of the race? In a world of athletes who all train and compete intelligently, talent and potential only go so far. Great—and wasted—potential litters the road to success. Will the current leader dig deep, run a smart race, respond to the elements, and live up to expectations? Time, and intelligence, will tell.

Now you ask me, "What does a marathon have to do with LEDs? Do you really know what you're talking about?" I think so. Like a strong runner leading a marathon, LEDs hold promise in the world's race to produce more energy-efficient lighting. A major technological advance over both incandescent and fluorescent lighting, LEDs use less energy, last longer, and allow more control of color and direction of light.

In 2010, lighting consumed an estimated 19% of U.S. electricity.1 By the year 2030, lighting could consume a full 767 terawatt-hours (TWh) annually.2 What an opportunity for that lead runner in our fanciful marathon! LEDs for lighting could reduce that electricity consumption by 25% by 2030.2 Moreover, LEDs could ease the quantity and type of solid waste generated by lighting, because they last up to five times longer than other lighting solutions and contain no toxic materials. Eventually replacing LEDs will not necessarily occur because of lamp failure, but simply as the result of architectural style. Furthermore, the ability to fine-tune color with red, green, and blue (RGB) LEDs adds new options for performance and creativity. Ultimately, LEDs will function well beyond illuminating a space. They will simply look and fit better with new styles and fixtures.

LED Intelligence—Essential for Winning the Race

How will LEDs fulfill their tremendous potential? Undoubtedly, the first hurdle is price. LEDs currently cost an order of magnitude more than existing lighting solutions. Saving energy is often not enough to convince price-conscious businesses and consumers to make the more expensive purchase. Manufacturing savings and volume production will likely reduce prices over time, but will costs drop enough and can it come fast enough to win over users? Those trends are uncertain and entirely debatable. Admittedly, they are beyond the scope of this article. Consider also availability, which affects price. Go to any two hardware stores and try to find the same LED lamp. It's tough. Many retailers do not stock sufficient variety or quantity of LED lamps to pull in the casual consumer. Why? It comes back to price and efficient inventory turns. So where does that leave us, as engineers, innovators, and creative thinkers? How do we enable LED lighting to reach its potential? To win the marathon?

Let's give LED lights intelligence, make them smart. Let's give these lights eyes, a voice, and the ability to count. Designing high-value semiconductors into lighting applications will optimize energy efficiency, maximize lamp lifetime, and reduce maintenance costs. Then LEDs will run the rest of the race, hard and strong, and they will win the race by running smart.

Essential Elements of LED Intelligence

Ambient light sensing, communications, and energy measurement make up the critical components of an intelligent lighting system. Ambient light sensing allows lights to dim when other sources of light already light a space sufficiently. In addition, sensors that detect the color of ambient light permit color tuning of advanced RGB LED lighting systems. Communication permits remote control and central networking of both small and large lighting installations. Energy measurement provides accurate accounting of consumed power and system insight for predictive maintenance. All of these features—ambient light sensing, communication, and energy measurement—translate into energy conservation and lower operating costs. In this application note, I explore the critical design considerations of adding ambient light sensing, communication (both wireless and powerline), and energy measurement to LED lighting systems. Reference design examples are presented.

An ambient light sensor (ALS) detects the amount of light in the proximity of the sensor. These simple devices become the "eyes" of an LED lighting system, and also the throttle. When there is already light in the room, lighting is completely unnecessary. The lamps can be dimmed or turned off completely, reducing power consumption and increasing lamp lifetime. Features critical to an ALS include current consumption, lux range, and IR and UV blocking. These sensors must quietly exist in the system; they cannot pull excess energy that defeats their purpose of conserving system energy. Excellent ALSs perform with less than 1µA of current. Lux range must exceed typical ranges of lux for a given outdoor application. A range from 0.1lx to 100,000lx generally encompasses most applications. A slightly higher band may be necessary for system robustness. IR and UV blocking remove any unwanted light in the nonvisible spectrum from the actual system readings.

Light Sensing

Figure 13 shows the placement of an ALS in a luminaire. The sensor must reside beyond the light of the lamp itself to prevent artificial light from affecting the ambient measurement. In this design, the ALS resides on a separate board and receives shade from the beam supporting the lamp. This straightforward design enables the ALS to turn off the lamp when morning light exceeds a preprogrammed value. RGB sensors can add even more "character" to a lighting application. LED systems like the one pictured here that are equipped with RGB LEDs and ALSs can dynamically tune their color output for application-specific requirements, such as mood lighting on a terrace or department store lighting for a display.

APLIKASI CATATAN 5383

Menambahkan Intelijen untuk LED Lighting

Oleh: David Andeen, Direktur Aplikasi, Maxim Integrated

Abstrak: Bagaimana cerdas sistem pencahayaan LED Anda? Sementara pencahayaan LED memegang janji mengurangi konsumsi energi dan biaya pemeliharaan, pintar desain pencahayaan LED meningkatkan kinerja sistem di kedua daerah, mencapai kinerja yang lebih tinggi per watt dan mengurangi biaya dalam jangka panjang. pengukuran energi, penginderaan cahaya ambient, dan komunikasi berfungsi sebagai pilar desain pencahayaan LED cerdas. pengukuran energi menyediakan sistem kesehatan dan informasi konsumsi. penginderaan cahaya ambient mengurangi sebuah LED pada waktu, menghemat energi dan memperpanjang dioda seumur hidup. Komunikasi link bersama setiap luminer untuk identifikasi koordinasi pemeliharaan dan sistem tingkat. Kontribusi komponen untuk kinerja sistem secara keseluruhan akan dieksplorasi.

Sebuah versi yang sama dari artikel ini muncul di EDN, 12 Juni 2012.

pengantar

Bayangkan maraton pada sangat panas, hari berdebu ketika menyimpan setiap ons hal energi untuk hasil. ras ini tidak setengah lebih, tapi pemenang tampaknya tertentu. memimpin terlihat dapat diatasi, karena pelari ini dapat melakukan lebih banyak dengan sedikit energi. pelari ini bersinar terang. Dalam menghadapi panas dan kompetisi, pelari ini tetap dingin. Sejauh ini bagus. Namun, akan pesaing ini mengatur kecepatan dan terus memimpin di paruh kedua balapan? Dalam dunia atlet yang semua kereta dan bersaing secara cerdas, bakat dan potensi hanya pergi sejauh ini. Besar-dan terbuang-potensi tandu jalan menuju sukses. Akan pemimpin saat menggali lebih dalam, menjalankan ras cerdas, menanggapi unsur-unsur, dan memenuhi harapan? Waktu, dan kecerdasan, akan memberitahu.

Sekarang Anda bertanya kepada saya, "Apa memang memiliki maraton dilakukan dengan LED? Apakah Anda benar-benar tahu apa yang Anda bicarakan?" Aku pikir begitu. Seperti pelari yang kuat terkemuka maraton, LED menjanjikan dalam lomba dunia untuk menghasilkan pencahayaan lebih hemat energi. Sebuah kemajuan teknologi utama lebih baik pijar dan lampu neon, LED menggunakan lebih sedikit energi, tahan lama, dan memungkinkan kontrol yang lebih dari warna dan arah cahaya.

Pada tahun 2010, pencahayaan dikonsumsi diperkirakan 19% dari AS electricity.1 Pada tahun 2030, pencahayaan bisa mengkonsumsi penuh 767 terawatt-jam (TWh) annually.2 Apa kesempatan untuk itu pelari memimpin dalam maraton fantastis kami! LED untuk penerangan bisa mengurangi konsumsi listrik sebesar 25% oleh 2.030,2 Selain itu, LED bisa meringankan jumlah dan jenis limbah padat yang dihasilkan oleh pencahayaan, karena mereka bertahan hingga lima kali lebih lama dari solusi pencahayaan lain dan tidak mengandung bahan beracun. Akhirnya menggantikan LED tidak akan selalu terjadi karena kegagalan lampu, tetapi hanya sebagai akibat dari gaya arsitektur. Selanjutnya, kemampuan untuk menyempurnakan warna dengan (RGB) LED merah, hijau, dan biru menambahkan pilihan baru untuk kinerja dan kreativitas. Pada akhirnya, LED akan berfungsi dengan baik di luar menerangi ruang. Mereka hanya akan terlihat dan lebih cocok dengan gaya baru dan perlengkapan.

LED Intelligence-penting untuk Memenangkan Race

Bagaimana LED akan memenuhi potensi yang luar biasa mereka? Tidak diragukan lagi, rintangan pertama adalah harga. LED saat ini biaya urutan besarnya lebih dari solusi pencahayaan yang ada. Menghemat energi sering tidak cukup untuk meyakinkan usaha sadar-harga dan konsumen untuk melakukan pembelian lebih mahal. tabungan manufaktur dan volume produksi kemungkinan akan menurunkan harga dari waktu ke waktu, tetapi akan biaya cukup drop dan dapat itu datang cukup cepat untuk memenangkan pengguna? Mereka tren tidak pasti dan seluruhnya bisa diperdebatkan. Diakui, mereka berada di luar lingkup artikel ini. Pertimbangkan juga ketersediaan, yang mempengaruhi harga. Pergi ke dua toko perangkat keras dan mencoba untuk menemukan lampu LED yang sama. Itu sulit. Banyak pengecer tidak saham berbagai atau kuantitas lampu LED yang cukup untuk menarik konsumen kasual. Mengapa? Muncul kembali ke harga dan perputaran persediaan efisien. Jadi bagaimana meninggalkan kita, sebagai insinyur, inovator, dan pemikir kreatif? Bagaimana kita mengaktifkan pencahayaan untuk mencapai potensinya LED? Untuk memenangkan maraton?

Mari kita beri lampu LED intelijen, membuat mereka cerdas. Mari kita beri mata ini lampu, suara, dan kemampuan untuk menghitung. Merancang semikonduktor bernilai tinggi ke dalam aplikasi pencahayaan akan mengoptimalkan efisiensi energi, memaksimalkan seumur hidup lampu, dan mengurangi biaya pemeliharaan. Kemudian LED akan menjalankan sisa balapan, keras dan kuat, dan mereka akan memenangkan perlombaan dengan menjalankan pintar.

Elemen penting dari LED Intelijen

Ambient light sensor, komunikasi, dan pengukuran energi membentuk komponen penting dari sistem pencahayaan cerdas. penginderaan cahaya ambient memungkinkan lampu redup ketika sumber cahaya lain sudah menyalakan ruang yang cukup. Selain itu, sensor yang mendeteksi warna ambient warna tala izin cahaya canggih RGB LED sistem pencahayaan. Komunikasi memungkinkan remote control dan jaringan pusat dari kedua instalasi pencahayaan kecil dan besar. pengukuran energi memberikan akuntansi akurat dikonsumsi kekuasaan dan sistem wawasan bagi mai prediksi

Figure 1. The ALS is mounted on a separate PCB and placed underneath the shadow of the luminaire's support beam. This prevents the sensor from reading light from the lamp itself.

Communications

Now let's talk about smart communication in LEDs. Ears and a voice are the next most critical features to make an LED light intelligent. By simply networking lights, you can turn them on and off, or dim them, via the network. This operation alone will reduce energy consumption. Communication also provides quick feedback for outages, necessary maintenance, and emergency situations. This information will save overall system maintenance costs. Both wireless and wired communication methods work effectively in various situations, depending on the network size and geography. Wireless works well in small indoor and larger outdoor applications with a continuous line of sight, available frequency bands, and sufficient headroom for transmission power. Powerline communication (PLC) uses the existing power lines to provide the communication. PLC works extremely well in large municipal-style lighting installations, tunnels, and indoor parking garages where line of sight is not possible because of geography or building walls. In all communication applications, reliability and robustness are critical. If communication fails, the system provides no benefits.

In wireless applications, signals may run over Wi-Fi®, ZigBee®, or other standard and proprietary protocols often in, but not limited to, the industrial, scientific, and medical (ISM) radio bands. Limiting power consumption provides network flexibility and is critical if endpoints use batteries. Figure 2 shows a unique application in which a light switch is equipped with an energy-harvesting RF transceiver. The system harvests the energy used to flick the switch, resulting in a usable DC voltage that powers the radio communication over < 1GHz RF to the light fixture. This switch can be placed anywhere in a room, provided that the signal reaches the luminaire. Without the need to wire the light switch, room design becomes more flexible and lighting control more dynamic.

Figure 2. A building automation application in which the light switch contains an unwired, energy-harvesting RF transceiver that controls the LED lighting.

PLC control of lighting uses the existing lines that already deliver power, thus making this method a cost-effective choice. PLC eliminates concerns such as sharing communication frequencies, performance in bad weather, and network maintenance, because communication occurs over maintained lines already delivering power. Range, speed, and robustness are the critical design considerations with PLC. Powerlines carry a tremendous amount of noise, which affects system robustness. G3-PLC™ communication is a new OFDM-based PLC standard that provides excellent communication over power lines. This standard allows for speeds up to 300kbps, mesh networking capability, and robust mode for high-noise situations. OFDM-based, PLC-controlled lighting networks similar to G3-PLC already exist. Figure 3 shows the PLC installation for a tunnel lighting network by Nyx Hemera Technologies.4 This system has already saved 25% in energy and 30% in reduction of maintenance. This large-scale installation supports up to 1022 lights on a single system and communicates over distances of up to 3km.

Figure 3. An example of a municipal streetlight network using PLC.4

Energy Measurement

Finally, smart LED lights need the ability to count watts. Each smart grid installation, from smart meters to voltage controllers to electric vehicle chargers, features energy measurement that gives utilities and customers accurate knowledge of power use in real time. Major lighting installations that report back their consumption provide finer granularity about building and municipal lighting situations. In this way, they can ensure that utilities only charge for the exact amount of energy used. By dimming or turning these lights off when not in use, they become responsive to user demand. Furthermore, variation in the energy consumption of specific lamps can signal a need for system repair, maintenance, or replacement. There is no doubt that with many lighting installations in areas difficult to access, optimizing maintenance will save money. To produce usable data in a smart grid, energy-measurement designs must provide a high level of accuracy across a wide current range. Furthermore, limiting or eliminating calibration time reduces overall system cost. Figure 4 shows a flexible LED lighting reference design featuring energy measurement.5 The energy-measurement chip also provides system dimming and a DALI interface.

Many municipalities are currently installing LED lighting without intelligent features. This will generate tremendous future opportunity for retrofit modules that enhance the performance of LED lights. To be upgradeable, these systems need interfaces that permit links to the intelligent lighting system. Given the cost and volume of LEDs, merely replacing relatively new and efficient LEDs will not be cost effective. Simple interfaces, such as DALI, will allow future addition of ALS, communications, and energy measurement.

Figure 4. A complete smart LED lighting reference design, featuring energy measurement, ambient light sensing, and communication.

The Finish Is Most Promising

Where does this leave us? The race for industry and consumers to transition to LEDs will be a long one. It is clear that LED lighting holds the potential to transform lighting and save tremendous amounts of energy. Adding the critical elements of "intelligent" lighting—ALS, communication, and energy measurement—will make LEDs far more useful and appealing. The measurement data supplied by smart LEDs will further reduce the energy consumption of that lighting system. It will lower operational and maintenance costs. With intelligence, LEDs can reach their full potential and beat out traditional forms of lighting in the race that is already being run every day.

References

1. Navigant Consulting, "2010 U.S. Lighting Market Characterization," January 2012, page xii, (http://apps1.eere.energy.gov/buildings/publications/pdfs/ssl/2010-lmc-final-jan-2012.pdf).
2. Navigant Consulting, "Energy Savings Potential of Solid-State Lighting in General Illumination Applications 2010 to 2030," February 2010, page 36, (http://apps1.eere.energy.gov/buildings/publications/pdfs/ssl/ssl_energy-savings-report_10-30.pdf).
3. Kannisto, Marko, and Simpson, Dan, "Intelligent Lighting Controller Measures Ambient Light and Knows the Time," Smart Energy DesignLine, March 2012.
4. Application note 5347, "Powerline Communications Automating Street Lighting."
5. Unterkofler, Klaus, 2011 Light Fair International demonstration, Maxim Integrated.

G3-PLC is a trademark of Maxim Integrated Products, Inc.

Wi-Fi is a registered certification mark of Wi-Fi Alliance Corporation.

ZigBee is a registered trademark and registered service mark of the ZigBee Alliance.