Design and Development of an Efficient, High Power Factor, Low-Cost, RGB LED System for Tuneable Lighting Application

Abstract

Branded smart red (R) – green (G) – blue (B) light emitting diode (LED) products commercially available in developing countries are too costly to afford for most of the population, especially for household applications. Locally manufactured cheaper alternatives of such products suffer from poor power factor and reduced circuit efficiency. To address these technical issues, a smart RGB LED system is presented here which offers high input power factor, good circuit efficiency, and at the same time lower fabrication cost and user-friendly control interface. The unique features of the proposed system are the front-end AC/DC converter is a constant-voltage, multiple-output flyback converter that mitigates the need of multiple drivers and inductors. The second is that the same converter is operated in discontinuous conduction mode to achieve a high input power factor. The third is that for dimming and colour tuning, pulse width modulation (PWM) control of the MOSFET switches is accomplished by an Arduino Mega 2560 microcontroller instead of other costlier and more sophisticated options. And the fourth is that the microcontroller gets its command signal from a smartphone or computer through an HC‑05 Bluetooth module. Through laboratory testing, it is confirmed that the LED system offers close-to-unity input power factor (0.928–0.985) and high efficiency of (88.14–95.46) % for a wide range of colour and luminous intensity. A comparative study reveals that the developed system is a better option than the earlier reported prototypes of multicolour LED systems in terms of the bill of material, economy, power factor, and efficiency.