A new approach to design EMI filter for two stage power LED driver

Abstract

Nowadays, the incadescent, florescent, and high-pressure mercury lamps was replaced by the LED (Light-Emitting-diode) …due to the high efficiency, enviromenttally friendly and long lifetime. Design the LED driver according to the industry standard for mass production is a matter of concern of goverment. However, the design of LED driver will be meet some difficulties due to comply with many standards as efficiency, harmonic, power factor, voltage/current ripple and EMI. In Vietnam, the study of EMI was not received the consideration because of difficulties in building a laboratory for measuring EMI as well as the cost of measurement of the qualified test center is quite high. In this paper, we investigate the design of EMI filter for LED driver which is bulit based on two-stage topology: Boost-PFC stage and LLC resonant half-bridge DCDC converter. Futhermore, this paper proposed new EMI filter by reducing the fitler coil. As comapre to the conventional method, the size and cost of the EMI filter in this paper is dramatically reduced. The experimental resutls are proved that the performance of proposed LED driver are complied with Vietnam Standard. In order to demonstrate the effectiveness of the proposed method, an experimental setup was built in laboratory. Three case studies with difference EMI fitler was shown and compared. We have received certificate for EMI with the proposed LED driver topology.