Advanced Discrete-Time Modeling and State Feedback Control of an Interleaved Buck Converter

Onboard DC micro grids in electric transport is a demanding application that requires high quality steady-state and transient performance of the power converters and their control. To address this, a three-phase interleaved DC-DC converter together with an advanced observer-based control scheme are used in this paper. To enable implementation of this control, a practical discrete-time model of the converter is proposed that reduces a fourth order system to a second order, without a significant loss of accuracy. The proposed model provides closedform solutions for all associated coefficients and gains. Based on this model, observer-based state feedback control is tested in this paper by simulation and shows superior performance to PI control. Experimental validation in underway.