ANonisolated Wide Input Series Resonant Converter for Automotive LED Lighting System

Abstract

—In this article, a reconfigurable nonisolated buck boost (BB) integrated full-bridge series resonant converter (FB SRC)basedlight emitting diode (LED) driver is proposed for wide input voltage automotive lighting applications. The proposed LED driver is derived by the integration of BB operation with FBSRC. It can be reconfigured into three different resonant converter topologiessuchasBBintegratedFBSRC,BBintegratedhalf-bridge series resonant converter (BB-HBSRC), and conventional HBSRC and, hence, produces three levels of voltage gains. By transfor mation from one topology to other based on the input voltage range and with asymmetrical pulsewidth modulation control, it can operate for wide input voltage range while maintaining the soft switching. The main advantages of the proposed configuration are smooth transformation into three different topologies without anyadditionalswitchingdevices,notopologicaltransitionswithina switching cycle in steady state, use of simple proportional–integral controller, soft switching, and wider voltage gain with buck/boost operation. In addition, dimming control is also achieved using pulsewidth modulation technique. Detailed theoretical analysis of the proposed converter is presented. To verify the analysis and performance,aprototypeof22.7W,22.5VLEDdriverisdesigned, simulated, and tested for a wide input voltage range of 18 to 120 V.