A Lifting Approach for Stability and Controller Design of Power Electronics with Constant Power Loads

A lifting approach is proposed for the modeling and controller design of nonlinear power electronics converters with Constant Power Loads (CPLs). The analysis of converters with active loads is challenging due to the nonlinear CPL disturbance, which is modeled as a rational function. An extra state is proposed to transform the system into polynomial form more suitable for stability and controller design using linear matrix inequalities and sum of squares methods. The proposed approach ensures the lifted system represents the original model without approximation errors. Methods are then developed for the estimation of the region of attraction and controller design using sum of squares programming. Real time simulation results are presented to demonstrate the performance and feasibility of implementation of the proposed controller.