Design and Realization of 1 kW LLC converter : Design of PCB and simulation

Sammanfattning

This thesis presents the design, simulation, and evaluation of a 1 kW LLC resonant converter incorporating a center-tapped transformer and synchronous rectification on the secondary side. The work builds upon a previous master’s thesis, which optimized the primary side using a planar transformer and unbalanced flux core. In contrast, this study focuses on enhancing the secondary side by replacing conventional diode rectifiers with low-RDS(on) MOSFETs driven by an IR1168 controller, aiming to reduce conduction losses and improve efficiency under high current loads. The methodology involves reusing the validated primary-side design while developing a new synchronous rectified secondary stage. The complete circuit was designed in KiCad, simulated in MATLAB Simulink, and electromagnetically modeled using COMSOL Multiphysics to evaluate current distribution, core loss, and magnetic behavior. Simulation results confirm a regulated 48 V output at approximately 21 A, achieving soft switching and reduced conduction losses. The transformer design, winding configuration, and PCB layout were optimized to mitigate parasitic effects and thermal stress. The findings demonstrate that integrating a center-tapped transformer with synchronous rectification significantly improves converter performance while preserving resonant operation. This validates the approach as a viable solution for compact, high-efficiency power conversion in modern electronic systems.