Modelling and Nonlinear Control of a Magnetically Coupled Multiport DC-DC Converter for Automotive Applications

Abstract

This work presents a nonlinear control strategy for a magnetically coupled multiport dc-dc converter aimed at automotive applications. First, a behavioural dynamic model, based on averaging the power flowing among the ports, is derived. Then, a control algorithm, based on feedback linearization techniques, is proposed. Essentially, the controller ensures decoupling and a linear dynamic behaviour thanks to a transformation of control and state variables, and a conventional PI action is devised to render asymptotic stability, as well as robustness to load uncertainties. The inversion of the control transformation, which involves nonlinear terms, is carried out using linear approximations with no significant performance decay. Hence, simplicity and efficiency are the main features of the control design. The proposed controller is validated via experimental results.

Keywords

• Isolated multiport dc-dc converter
• bidirectional power flow
• nonlinear control
• feedback linearization
• decoupling
• phase-shifted pulse width modulation