Estimation the Amount of Heat Generated by LEDs under Different Operating Conditions (original) (raw)

Thermal Management of Power LED System

LEDs are used in many areas today. Street lighting is one of them and high-power LEDs are utilized in this area. Electrical energy is converted into light with an efficiency in 10-25% range. The rest is converted into heat. The generated heat is largely caused from LED chip. Furthermore, Driver circuit would also causes heat rise. Removing of this heat from the system is important in order to LED system efficiency because increasing of temperature causes a reduction of luminous flux. Excellent thermal management plays a significant role in terms of efficiency, reliability and durability. In this study, losses are caused from the LED chip and the heat sink which are part of the LED lighting systems are examined. These elements are thermally analyzed. The impacts of these losses on efficiency will be presented.

A General Photo-Electro-Thermal Theory for Light Emitting Diode (LED) Systems

IEEE Transactions on Power Electronics, 2009

The photometric, electrical, and thermal features of LED systems are highly dependent on one another. By considering all these factors together, it is possible to optimize the design of LED systems. This paper presents a general theory that links the photometric, electrical, and thermal behaviors of an LED system together. The theory shows that the thermal design is an indispensable part of the electrical circuit design and will strongly influence the peak luminous output of LED systems. It can be used to explain why the optimal operating power, at which maximum luminous flux is generated, may not occur at the rated power of the LEDs. This theory can be used to determine the optimal operating point for an LED system so that the maximum luminous flux can be achieved for a given thermal design. The general theory has been verified favorably by experiments using high-brightness LEDs.

Design Methodology For Led Lighting Systems Based On Photo-electro-thermal Interrelationships

Eletrônica de Potência, 2018

This paper presents a design methodology for LED (Light-Emitting Diode) lighting systems based on photo-electro-thermal (PET) interrelationships. The proposed methodology uses only LED datasheet information, which makes experimental tests unnecessary to obtain the design parameters. The methodology allows identifying several design specifications, such as, luminous efficacy, heatsink thermal resistance, LED junction temperature and forward current, essential aspects to produce a satisfactory lighting system. Thus, it is possible to define the lighting system features based on standards requirements to obtain the desired system results. Initially, a review of several PET theories is presented, and a new mathematical analysis is performed, in order to highlight the main contributions of the methodology. An LED bulb lamp design is presented to exemplify the methodology. Finally, experimental tests with the proposed LED lamp resulted in a luminous flux of 1271 lm, with a luminous efficacy of 112 lm/W, and LED junction temperature of 79.67 ºC. The errors between calculated and measured luminous flux, luminous efficacy and LED junction temperature were 3.70%, 1.88%, and 3.85%, respectively. These results validate the proposed methodology.

Influence of temperature in the performance of the LED lamp

Revista Brasileira de Aplicações de Vácuo, 2020

In this work, we analyze the temperature of the LED lamp of white emission with 9 W with or without the influence of the cooling process using a fan. The investigation was carried out by seven different methods: (1) Analysis of temperature close to LEDs inside the bulb (diffuser); (2) Analysis of temperature on LEDs without bulb; (3) Analysis of temperature on LEDs without bulb with cooling using a fan; (4) Analysis of temperature on LEDs board out of body lamp without bulb; (5) Analysis of temperature on LEDs board out of body lamp without bulb with cooling using a fan. This last analysis 5 exhibited better results, decreasing the significant temperature on the LED surface from ≈130ºC (found in analysis 2) to ≈45ºC. Due to good results exhibited in analysis 5, it was used in the illuminance measurements of the LED lamp without cooling in the analysis 6, and with a fan as analysis 7. Both results compared showed that using a fan had a great influence, and difference on the illuminance values by elapsed time from ≈47,000 lux without a fan (analysis 6) to ≈55,300 lux with fan (analysis 7), and also the use of a fan exhibited the lowest time of stabilization in 1 minute only.

Analysis of Thermal and Luminous Performance of MR-16 LED Lighting Module

IEEE Transactions on Components and Packaging Technologies, 2010

Light emitting diode (LED) with a long lifetime, low power consumption, and low pollution has been successfully applied in many products. However, due to its low electro-optical conversion efficiency, high percentage of input power transformed to redundant heat, thus increasing the LED temperature. This phenomenon decreases the luminous flux, changing light color, and useful life span of LED. Therefore, thermal management becomes an important issue in high power LED. In this paper, the variation of luminous flux and light color for different LED lighting modules under long time operation has been measured and discussed. In addition, a detailed finite element model of LED lighting module, MR-16, with a corresponding input power and suitable boundary conditions is established by using the ANSYS finite element analysis program. Furthermore, to validate the simulation results, the current-voltage-temperature method for characterization of a diode is utilized to measure the junction temperature of LED chip indirectly and compare with simulation results. After the simulation is validated, various thermal performance assessments under the different design parameters of the LED package and lighting module are also investigated in this paper. The methodology and analysis results of this paper can provide a guideline for the LED lighting module such as MR-16 design in the future. Index Terms-Finite element analysis, light emitting diode, light emitting diode (LED) lighting module, thermal management.

Thermal Simulation and Analysis of the Single LED Module

JST: Smart Systems and Devices, 2021

Light Emitting Diodes (LED) shows an important role in replacing traditional lamps due to their longevity, high efficiency, and environment-friendly operation. However, a large portion of the electricity applied on LED converts to heat, raising up the p-n junction working temperature, and lowering the output-light quality and the LED lifetime as well. Therefore, thermal management for LED is one of the key issues in LEDs lighting application. In order to investigate the impact of each component of the LED module on the junction temperature of the LED, we have performed thermal simulations of a typical single LED module by using the finite element method. Effects of thermal conductivity and thickness of each module’s components on junction temperature were analyzed systematically. The results provided a detailed understanding of thermal behavior of a single LED module and established a crucial insight into thermal management design for high-power white LED lamp. Thermal-interface-mat...

Design and Thermal Analysis of High Power LED Light

2021

In the development of lighting technologies, light emitting diode (LED) technology plays an important role due to its high efficiency. LED lightening is the future of indoor and outdoor illumination solutions that all around of the world there is a widespread transition to save energy and have better quality illumination via LED-based solutions. On other hand, cooling of high power LED is crucial factor to utilize LED in high performance. In addition, finned heat sink could not be efficient based on the its geometry and usage areas due to the powder, the rain and the muds effects. In this study, an un-finned heat sink LED armature consisting of aluminum sheet metal was designed using a computer-aided-design (CAD) program. Furthermore, manufacturing of the heat sinks from sheet metal plates with bending machines enables to increase variety of LED armatures cheaply according to design requirements. Then, the thermal analysis of the system was conducted for the case of natural heat con...

Thermal management of multiple LEDs for high-power lighting applications

International Journal of Experimental Research and Review, 2023

Power LED lighting has suffered from substantial heat generated, leading to significant performance degradation. Consequently, achieving an optimal distribution of LEDs is essential to ensure high luminance efficiency. Implementing effective thermal treatment is important to prevent any potential degradation in the performance of the LED lighting system. Optimizing the arrangement of individual LEDs is a promising approach to mitigating heat accumulation issues. In this paper, we propose a reasonable approach to obtaining the optimal distribution of LED lighting systems under DC biasing and PWM operating conditions. The thermal analysis simulation was performed based on the theoretical assumption to evaluate the thermal distribution of a single LED. Thermal analysis was conducted on an LED lighting system with 20 LEDs, and the distance between LEDs ranged from 4 mm to 24 mm. The simulated analysis showed that the maximum temperature could be controlled from 65.1 ℃ to 58.7 ℃. We discussed the optimum arrangement of LEDs and how heat generated by an LED influences the system. In addition, the LED lighting was operated in PWM mode to mitigate the thermal issues. The relationship between luminance efficiency and operation condition is discussed. Thus, the luminance efficiency improved from 114.8 lm/W to 126.8 lm/W, and the thermal relaxation time was no longer than 0.013 s. The process of determining the optimal distance between LEDs was very effective in achieving an optimized power operating condition and LEDs distribution in the module for a compact volume and enhanced performance.

LED lamp - design and thermal management investigations

2012 35th International Spring Seminar on Electronics Technology, 2012

The aims of this work are connected with development of new method of LEDs' mounting onto the heat sink in lighting equipment. The technique involves usage of copper pins instead of standard MCPCBs. LEDs are soldered on copper pins. Mounting of LEDs demands boring holes in the heat sink and fixing copper pins into the holes by thermal conductive epoxy resin only. LED lamp is made using new technology and LEDs' thermal performance investigations are made at various ambient conditions (air temperatures from 20ºC to 45ºC) and different current values through LEDsup to 600 mA. Temperature regimes of operation of power LEDs soldered on MCPCBs and on copper pins (and mounted on heat sink) are experimentally tested and compared. Experimental results show that utilization of copper pins underneath LED thermal pads ensures good dissipation of heat, good manufacturability, enables varied designs of light equipment and is cost effective.