Resonant converters: nonlinear analysis and control

The current trends in development and deployment of advanced switching converters have facilitated the unified activities in topology design, nonlinear analysis, optimization, and control. In this paper, by using nonlinear models of resonant converters, bounded controllers are designed to ensure a spectrum of performance objectives required. To attain high efficiency and power density, new converter topologies were developed. It is recognized that advanced closed-loop configurations must be designed to guarantee a spectrum of specifications and requirements imposed on the converter dynamics. The output voltage of converters is regulated by changing the duty ratio, which is constrained by lower and upper limits. In this paper, to approach design tradeoffs and analyze converter performance (settling time, overshoot, stability margins, and other quantities), the constraints and nonlinearities are thoroughly examined. Innovative controllers are synthesized to ensure performance improvements. To illustrate the control laws designed and to validate these algorithms, analytical and experimental results are presented and discussed. In particular, nonlinear analysis and design with experimental verification are performed and documented for a resonant converter with zero-current-switching.