PWM current controller design for multi-level DC-DC converter via singular perturbation technique

The problem of current regulation for a multilevel DC-DC converter is discussed. The paper addresses PI control with an additional low-pass filtering and a high-frequency pulse-width modulation (PWM) in control loop. The problem of controller design is reduced to the continuous-time controller design based on the Filippov´s average model of the multi-level DC-DC converter. The design methodology of PI controller via singular perturbation technique is presented where two-time-scale motions are artificially induced in the closed-loop system. The method of singular perturbations is used throughout the paper. Numerical simulations are included.