Multileg Interleaved Buck Converter for EV Charging: Discrete-Time Model and Direct Control Design
Stefania Cuoghi, Riccardo Mandrioli, Lorenzo Ntogramatzidis, Gabriele Grandi
Abstract
This paper presents the modeling and the implementation of the digital control of a multileg interleaved DC-DC buck converter for electrical vehicle (EV) charging. Firstly, we derive a discrete averaged model of an n-leg interleaved buck converter (IBC). Secondly, we present a direct tuning procedure for one primary discrete PIDF (PID + filter) and multiple secondary PI controller. The objective of the control system is to regulate the current flow in each leg of the converter. This task is accomplished by introducing a novel control paradigm that simultaneously addresses two aims: on the one hand, the control scheme must guarantee an acceptable level of robustness under load variations; while on the other, an even distribution of power on each leg must be ensured at any operational condition. The proposed strategy hinges on a technique that combines simplicity and precision in the fulfillment of design frequency specifications. We use simulations and a digital signal processor (DSP) based experimental implementation of the design technique to validate the proposed methodology.