Prognostics and health management of light emitting diodes

Prognostics is an engineering process of diagnosing, predicting the remaining useful life and estimating the reliability of systems and products. Prognostics and Health Management (PHM) has emerged in the last decade as one of the most efficient approaches in failure prevention, reliability estimation and remaining useful life predictions of various engineering systems and products. Light Emitting Diodes (LEDs) are optoelectronic micro-devices that are now replacing traditional incandescent and fluorescent lighting, as they have many advantages including higher reliability, greater energy efficiency, long life time and faster switching speed. Even though LEDs have high reliability and long life time, manufacturers and lighting systems designers still need to assess the reliability of LED lighting systems and the failures in the LED. This research provides both experimental and theoretical results that demonstrate the use of prognostics and health monitoring techniques for high power LEDs subjected to harsh operating conditions. Data driven, model driven and fusion prognostics approaches are developed to monitor and identify LED failures, based on the requirement for the light output power. The approaches adopted in this work are validated and can be used to assess the life of an LED lighting system after their deployment based on the power of the light output emitted. The data driven techniques are only based on monitoring selected operational and performance indicators using sensors whereas the model driven technique is based on sensor data as well as on a developed empirical model. Fusion approach is also developed using the data driven and the model driven approaches to the LED. Real-time implementation of developed approaches are also investigated and discussed

DESAIN BARU PADA PENERANGAN JALAN DENGAN PENDEKATAN HOMOGENIUSES LUMINAIRES DAN NON-HOMOGENIUSES

Proses pergantian teknologi penerangan jalan umum (PJU) dari lampu high pressure sodium (HPS) menjadi lampu Light Emitting Diode (LED) sering kali mengalami kesalahan desain, yang berakibat tidak menghasilkan efisiensi energi yang sesuai harapan. Penelitian ini bertujuan untuk melakukan proses desain ulang PJU yang sudah menggunakan teknologi LED dengan menggunakan pendekatan Homogeniuses dan Non-Homogeniuses Luminaires. Studi dilakukan pada sebuah ruas jalan di kota Bandung yang memiliki Panjang 734 meter, dengan jumlah tiang lampu LED sebanyak 16 buah. Proses desain ulang menggunakan perangkat lunak open source DIALux Evo 8. Simulasi yang dilakukan memberikan hasil bahwa pendekatan Homogeniuses Luminaires lebih baik dalam hal penggunaan energi dan lebih ekonomis dari pendekatan Non-Homogeniuses Luminaires, karena dapat mereduksi kebutuhan jumlah tiang yang diperlukan, dan menghasilkan pencahayaan yang sesuai SNI. Proses desain PJU yang baik harus mempertimbangkan aspek teknis dan pembiayaan yang tepat dapat memberikan keuntungan bagi pengguna jalan dan pemerintah kota. The process of changing roadway lighting technology from high pressure sodium lamps to Light Emitting Diode (LED) lamps often experiences design errors, which results in not producing energy efficiency as expected. This study aims to conduct a process of redesigning PJU that has used LED technology using a homogeniuses and non-homogeniuses luminaire approach. The study was carried out on a road in the city of Bandung that has a length of 734 meters, with the number of LED light poles as many as 16. The simulation results show that the Homogeniuses Luminaires approach is better in terms of energy use and more economical than the Non-Homogeniuses Luminaires approach, because it can reduce the need for the number of poles needed, and produce lighting that according to SNI. A good PJU design process must consider the technical aspects and the right financing can benefit road users and the city government

Sustainable Development (SD) Design of an Electrical System A Case Study of Asiaflex Products Sdn B lid

Sustainable development (SD) is a simple way of ensuring a better quality of life for everyone, now and for generation to conic. It refers to a perspective that considers all three aspects which are social, economic and the environmental. Designing an electrical system with sustainability refers to an approach that considers the use of renewable energy, energy efficiency, conservation and nlnmising usage of natural resources

Novel Offline Switched Mode Power Supplies for Solid State Lighting Applications

In recent years, high brightness light emitting diodes (HBLEDs) have increasingly attracted the interest of both industrial manufacturers and academic research community. Among the several aspects that make LED technology so attractive, the most appreciated characteristics are related to their robustness, high efficiency, small size, easy dimming capability, long lifetime, very short switch-on/switch-off times and mercury free manufacturing. Even if all such qualities would seem to give to solid state lighting a clear advantage over all the other kinds of competing technologies, the issues deriving from the need of LED technology improvement, on one hand, and of the development of suitable electronic ballasts to properly drive such solid state light sources, on the other, have so far hindered the expected practical applications. The latter problem, in particular, is nowadays considered the main bottleneck in view of a widespread diffusion of solid state technology in the general lighting market, as a suitable replacement of the still dominant solutions, namely halogen and fluorescent lamps. In fact, if it is true that some aspects of the devices’ technology (e.g. temperature dependent performance, light quality, efficiency droop, high price per lumen, etc…) still need further improvements, it is now generally recognized that one of the key requirements, for a large scale spread of solid state lighting, is the optimization of the driver. In particular, the most important specifications for a LED lamp ballast are: high reliability and efficiency, high power factor, output current regulation, dimming capability, low cost and volume minimization (especially in domestic general lighting applications). From this standpoint, the main goal is, therefore, to find out simple switched mode power converter topologies, characterized by reduced component count and low current/voltage stresses, that avoid the use of short lifetime devices like electrolytic capacitors. Moreover, if compactness is a major issue, also soft switching capability becomes mandatory, in order to enable volume minimization of the reactive components by increasing the switching frequency in the range of the hundreds of kHz without significantly affecting converter’s efficiency. It is worth mentioning that, in order to optimize HBLED operation, also other matters, like the lamp thermal management concern, should be properly addressed in order to minimize the stress suffered by the light emitting devices and, consequently, the deterioration of the light quality and of the expected lamp lifetime. However, being this work focused on the issues related to the research of innovative driving solutions, the aforementioned thermal management problems, as also all the topics related to the improvement of solid state devices’ technology, will be left aside. The main goal of the work presented in this thesis is, indeed, to find out, analyze and optimize new suitable topologies, capable of matching the previously described specifications and also of successfully facing the many challenges dictated by the future of general lighting. First of all, a general overview of solid state lighting features, of the state of the art of lighting market and of the main LED driving issues will be provided. After this first introduction, the offline driving concern will be extensively discussed and different ways of approaching the problem, depending on the specific application considered, will be described. The first kind of approach investigated is based on the use of a simple structure relying on a single power conversion stage, capable of concurrently ensuring: compliance with the standards limiting the input current harmonics, regulation of the load current and also galvanic isolation. The constraints deriving from the need to fulfil the EN 61000-3-2 harmonics standard requirements, when using such kind of solution for low power (<15W) LED driving purposes, will be extensively discussed. A low cost, low component count, high switching frequency converter, based on the asymmetrical half bridge flyback topology, has been studied, developed and optimized. The simplicity and high compactness, characterizing this solution, make it a very good option for CFL and bulb replacement applications, in which volume minimization is mandatory in order to reach the goal of placing the whole driving circuitry in the standard E27 sockets. The analysis performed will be presented, together with the design procedure, the simulation outcomes and the different control and optimization techniques that were studied, implemented and tested on the converter's laboratory prototype. Another interesting approach, that will be considered, is based on the use of integrated topologies in which two different power conversion stages are merged by sharing the same power switch and control circuitry. In the resulting converter, power factor correction and LED current regulation are thus performed by two combined semi-stages in which both the input power and the output current have to be managed by the same shared switch. Compared with a conventional two-stages configuration, lower circuit complexity and cost, reduced component count and higher compactness can be achieved through integration, at cost of increased stress levels on the power switch and of losing a degree of freedom in converter design. Galvanic isolation can be provided or not depending on the topologies selected for integration. If non-isolated topologies are considered for both semi-stages, the user safety has to be guaranteed by assuring mechanical isolation throughout the LED lamp case. The issue, deriving from the need of smoothing the pulsating power absorbed from the line while avoiding the use of short lifetime electrolytic capacitors, will be addressed. A set of integrated topologies, used as HBLED lamp power supplies, will be investigated and a generalized analysis will be presented. Their input line voltage ripple attenuation capability will be examined and a general design procedure will be described. Moreover, a novel integrated solution, based on the use of a double buck converter, for an about 15W rated down-lighting application will be presented. The analysis performed, together with converter design and power factor correction concerns will be carefully discussed and the main outcomes of the tests performed at simulation level will be provided. The last kind of approach to be discussed is based on a multi-stage structure that results to be a suitable option for medium power applications, like street lighting, in which compactness is not a major concern. By adopting such kind of solution it is, indeed, possible to optimize converter’s behavior both on line and on load side, thereby guaranteeing both an effective power factor correction at the input and proper current regulation and dimming capability at the output. Galvanic isolation can be provided either by the input or the output stage, resulting in a standard two stage configuration, or by an additional intermediate isolated DC-DC stage (operating in open loop with a constant input/output voltage conversion ratio) that namely turns the AC/DC converter topology into a three stage configuration. The efficiency issue, deriving from the need of multiple energy processing along the path between the utility grid and the LED load, can be effectively addressed thanks to the high flexibility guaranteed by this structure that, relaxing the design constraint, allows to easily optimize each stage. A 150W nominal power rated ballast for street solid state lighting applications, based on the latter (three stage) topology, has been investigated. The analysis performed, the design procedure and the simulations outcomes will be carefully described, as well as the experimental results of the tests made on the implemented laboratory prototype

Increase Sustainability in Buildings Through Public Procurements: The PROLITE project for Lighting Retrofit in Schools

The Public Procurement has always been a demand-side policy measure with great opportunities in terms of spurring innovation at the scale of products and/or services. A support for a sustainable development in the field of energy and buildings may came from different types of Public Procurement: Green Public Procurement (GPP), Sustainable Public Procurement (SPP) and Public Procurement of Innovation (PPI). Within this framework, the paper presents a case study where PPI has been used to promote the development of innovative solutions for upgrading school buildings in terms of increased energy efficiency and sustainability

Reducing the Carbon Footprint of Data Centers

Data centers use a significant amount of energy and indirectly produce greenhouse gases which have a major impact on the environment. Architecture 2030 is a challenge to new buildings to build 100% carbon neutral buildings by the year 2030. The design achieved by this project can make headway in the right direction. The energy consumption of data centers can be dramatically reduced by implementing modern technology and rethinking the engineering behind traditional data centers. This is achieved by analyzing the traditional data center designs, and determining where the highest energy loses can be reduced and recouped. Techniques implemented include using liquid immersed servers, phase changing material infused building components, Stirling engines, and air-side economizers

Creating a Plan to Convert Streetlights in Southeast Michigan to Energy Efficient LED's by 2025

Street lighting plays an important role in the human landscape, providing public safety and place-making benefits. However, it is also the largest energy expense for many municipalities and accounts for significant environmental impacts. By converting their street lighting to LED bulbs, communities throughout Southeast Michigan have a great opportunity to save money, reduce their environmental impacts, and realize safety and aesthetic benefits for residents. However, municipalities’ participation in street lighting conversion projects has thus far been limited due to lack of information and communication about available community lighting options. This report, prepared on behalf of the Southeast Michigan Regional Energy Office (SEMREO), explores the following perspectives of the proposed LED streetlight conversion projects: technical feasibility, street lighting policy, environmental impact analysis, social and community analysis, and financial analysis of available funding mechanisms. For the technology analysis section, we performed a literature review of available street lighting technologies, with a focus on highlighting the energy and cost benefits of LED conversion project implementation. With their high efficacy and long lifetimes relative to conventional bulbs, LEDs were proven the best option for streetlight upgrades in Southeast Michigan. We also performed a policy analysis, examining policy incentives and disincentives for LED street lighting conversion projects in the state of Michigan, including utility incentives, legislative activities, and federal policy drivers. For our environmental analysis, we quantified the emissions reductions attributed to the demand reduction from the LED conversion project, and determined its potential as a cost-effective emissions reduction mechanism. In addition, we met with community members and identified the needs and preferences of the Eastpointe community, a SEMREO member, and found that participants were interested in the possibilities of solar-powered streetlights. Finally, we evaluated financing options and discussed financial barriers for undergoing such projects. This comprehensive analysis includes a simple streetlight This comprehensive analysis includes a simple streetlight conversion plan for communities in Southeast Michigan region and several recommendations for municipalities participating in SEMREO’s Street Lighting Consortium. First, we found this conversion plan to be economically favorable, saving municipalities an average of 55% of energy savings and 32% of annual expenses savings, with an average simple payback period of 3.7 years. For our recommendations, we emphasize that upgrading streetlights to LEDs creates significant economic, environmental and social benefits: communities should continue being Consortium members, take advantages of economies of scale, and remain active in public consultation processes. Additionally, we recommend that the Consortium continue to advocate for energy efficiency-friendly policies, such as stricter energy optimization standards and inclusion of LED conversion projects in the State Carbon Implementation Plan (SCIP), and that the Consortium style itself as an advocacy and resource organization with dues-based membership. Finally, it is recommended that SEMREO members increase their outreach opportunities with the public to gain more support for streetlight conversions. An integrated approach such as the one laid out in this report could accelerate LED implementation process, assess the benefits, and help to increase participation in future programs. Our results could also be applied to municipalities in Michigan outside of SEMREO’s target region, but further large-scale data analysis would be needed to support this project at a state-level scale.Master of ScienceNatural Resources and EnvironmentUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/117633/1/Final Report - Creating_A_Plan__to_Convert_Streetlights_SE_MI.pd