Passivity-based PI control of switched power converters

This paper addresses the practically important question of when a nonlinear system can be asymptotically stabilized with a linear PI control, and show that it is possible if the system can be passified with constant control actions. This result is used to propose a constructive methodology to design PI schemes for switched power converters, which are viewed from a novel perspective: with the switches acting as effective “port variables” that establish a passive mapping with suitably defined outputs. Detailed calculations are given for a three-phase rectifier and simulations with a realistic model compares the performance of the proposed PI with other linear and nonlinear designs.¹