I-V Mode Integrated Droop PI Controller for Automotive LED Applications

Abstract

Light-Emitting Diodes (LED) lights are the most economical choice of lighting scheme in terms of lumens per Watt and several other factors when compared with their traditional counterparts. This paper used control theory to model, simulate and analyze an LED driver adapted from the idea of synchro-droop cascaded PI controller (CDPI) used in its reduced DC form. The control method was applied to all the classic non-isolated versions of DC-DC converters and the behavior was then investigated in the time domain to prove its supremacy against a conventional PI controller (CPI). The simulation results obtained for these configurations under voltage and current control modes (I-V) show the efficacy of a boost converter as the topology, CDPI as the control technique, and boost as the gain mode. Among the basic DC converter topologies, the boost converter seems less affected by multiple disturbances in the line, reference voltage, and LED load transient changes with the CDPI control than with its single-stage CPI counterpart. Experimental analysis using a prototype hardware model powering up a 24/30 V, 200 mA, 27 W LED automotive dual string lamp load confirmed the simulation results