Modeling and Controller Design for a GaN-based AC-DC LED Driver

This paper presents the modeling and controller design for an AC/DC LED driver using Gallium Nitride (GaN) switching semiconductors. The proposed configuration integrates a full-bridge rectifier with a dc/dc Sepic converter. Firstly, the detailed modeling of the Sepic converter in discontinuous conduction mode (DCM) is presented. To facilitate the small-signal modeling process, the PWM averaging method is employed. A closed-loop controller is then implemented to ensure system stability. To establish a baseline for comparison, the controller parameters are tuned manually and via the Genetic Algorithm (GA). Simulation results confirm the accuracy of the modeling and demonstrate the effectiveness of the proposed controller design framework. Finally, the GaN switch is replaced by Silicon Carbide (SiC) and conventional Silicon (Si) to assess the driver efficiency. Simulation in the PLECS environment highlight the high efficiency of GaN switch and lower heat generation compared to SiC and Si, reducing the need for extensive cooling and potentially extending the converter's lifespan.