Analysis and experimentation with dissipative nonlinear controllers for series resonant DC/DC converters

The paper describes practical experience and analytical advances in a nonlinear controller design methodology for series resonant DC/DC converters. The control goal is to maintain the output voltage in the presence of large load perturbations by varying the switching frequency. The proposed methodology utilizes large scale, nonlinear switched and generalized averaged models, and the resulting closed-loop system is exponentially convergent under typical operating conditions. The designer has a direct handle over the convergence rate, and the nonlinear controller requires only the usual output voltage measurements, while the load variations are estimated. In this paper, the previously reported results are extended in two directions: (1) a dissipativity-based nonlinear controller is implemented in affordable analog circuitry, and evaluated experimentally; and (2) the control structure is generalized to allow for both resistive and current loads