Development of Chip Temperature and Cost-Based Optimum Design for a Radial Heat Sink Cooling High Power LEDs

Abstract

High power Light Emitting Diodes (LED)s are preferred in places that produce intense light output and have overheating problems because they work with high currents. Therefore, efficient thermal management is essential to ensure optimal performance and longevity. In the present study, a numerical analysis is conducted on a high-power Light Emitting Diode (LED) circuit with a Circuit on Board (COB) design featuring a radial heat sink. Additionally, a multi-objective optimization approach using the Desirability Function Approach (DFA) is introduced for the modeled radial heat sink. Two performance parameters, namely the maximum junction temperature and the cost of the radial heat sink, are defined as the objective functions, and the aim is to minimize both of these parameters. The independent variables for the objective functions are the geometrical parameters of the radial heat sink, namely the base radius (R), fin length (L), and heat sink height (H). The Response Surface Method (RSM) is applied to minimize sample numbers of the Design of Experiment (DOE) while still obtaining accurate response values. Furthermore, Analysis of Variance (ANOVA) is utilized to assess the fitting of the real response equations with the representative answer equations. The minimum prediction R2 is calculated to be 0.9748%, indicating a good agreement between the models. The optimum design for the radial heat sink is obtained, with the following dimensions: R=25 mm, L=15 mm, and H=55.36 mm. The response values for this optimal design are validated with a low error rate of 0.25% using numerical analysis.

Keywords

• High power LEDs
• thermal management
• optimization
• numerical analysis

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