Sliding-Mode Input–Output Linearization Controller for the DC/DC ZVS CLL-T Resonant Converter

A sliding-mode input-output linearization controller for the dc/dc zero-voltage switching (ZVS) CLL-T resonant converter is presented. The proposed controller significantly improves the transient response and disturbance rejection of the converter while preserving the closed-loop stability. An averaged large-signal dynamic model of the converter operating with a novel discrete ZVS modulation technique is developed and used as starting point for the controller design. Since the model derivation process does not include small signal approximations, it can be used for large-signal analysis, providing accurate predictions of the converter dynamic behavior. The combination of the proposed controller and modulation technique provides ZVS operation over a wide load range, narrowed regulating frequency range, robustness, and fast transient response against transient load changes. Experimental and simulation results are reported to validate the theoretical predictions and to confirm the superior performance of the nonlinear controller when it is compared with a conventional linear controller.