Steady-State Analysis of Asymmetrical Pulse-Width-Modulated Series Resonant Converter for Light Load Condition

This paper proposes a steady-state analysis of the asymmetrical pulse-width-modulated series resonant converter, commonly employed under light load conditions for effective voltage regulation. The proposed method achieves precise and explicit converter waveforms by applying the Laplace-based theorem to the converter’s ordinary differential equation with periodic and discontinuous inputs, without relying on approximations. By numerically determining the intermediate variables that define converter waveforms, the analysis provides accurate steady-state results based on system parameters. Furthermore, it derives an analytical solution to identify the load conditions suitable for asymmetrical pulse-width modulation operation, as well as the boundary load conditions for discontinuous conduction mode within this mode. The mathematical expressions derived for the converter waveforms and operational modes are validated through simulations using a switching model in PSIM software, as well as through experimental results.