Switching Control in DC-DC Converter Circuits: Optimizing Tracking-Energy Tradeoffs

This paper concerns the problem of optimal switching control in voltage converter circuits, where the objective is to minimize a cost-performance function comprised of the sum of a tracking-related measure and the switching energy. Most of the existing approaches to optimal switching are based on continuous-parameter optimization and optimal control techniques, which are mostly suitable to continuous-parameter functions such as tracking-related performance metrics. On the other hand, the switching-energy cost performance is inherently a discontinuous function dependent on the number of switchings, and hence its inclusion in the problem often is done in ad-hoc ways. This paper explores a systematic approach to optimizing performance - energy tradeoffs by extending an algorithm for optimizing tracking, developed by the authors, to include the energy performance via an averaging technique. The problem is posed in the setting of Pulse Width Modulation, and the controlled variables are the cycle time and duty ratios at each cycle. Extensive simulation results suggest the potential generality of the proposed approach.