A dissipativity-based controller for series resonant DC/DC converters

This paper describes a controller design methodology for series resonant DC/DC power converters. The control goal is to maintain the output voltage in the presence of large load perturbations by varying the switching frequency. This 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. When compared to fixed, robust linear compensators, the performance is greatly improved as the duration of a transient is decreased more than an order of magnitude, while size of the output voltage excursion is less than half of the one typically achievable with linear compensators. The nonlinear compensator is fairly simple, as it comprises a static nonlinearity, a saturable integrator, and a few linear and logic elements.