Augmented State Approach in Quasi-Sliding-Mode Controlled PEBB-Based Power Converters

Abstract

Abstract A wide class of high power converters have modular structures as they are constituted of the connection of two-level modules, according to the power electronic building block (PEBB) concept. Moreover, the intrinsic variable structure nature of PEBBs makes sliding mode control an attractive solution. When complex configurations are considered the number of PEBBs can be different from the number of switching relations, and modularity concept is not still valid at control level. The present paper proposes and discusses a general and systematic approach which makes it possible to have a one-to-one correspondence between the number of PEBBs and the switching control laws. It makes it possible to preserve the modularity of PEBB allowing to have an embedded modulation strategy. In such a way, standard current-tracking algorithm can be applied at PEBB level. The approach is based on augmented state method and makes it possible to verify separately for each PEBB both sliding and reaching conditions. The proposed approach is verified and supported through simulation tests.