Interleaved Current Control for Multiphase Converters with High Dynamics Mean Current Tracking

Abstract

This paper presents a current control for high-power multiphase converters, where fast and precise current reference tracking is required, and limited switching frequency is present. The proposed control is based on a synchronization signal and current error comparison bands per phase. The control calculates the switching time that adjusts the phase current error zero-crossing points with the synchronization signal to control the current mean value and provide the correct phase shift among phases. The aforementioned comparison bands allow us to determine the current error slopes required to calculate the switching instants. This methodology permits the precise current reference tracking regardless the load voltage and the voltage drop in the semiconductor devices and in the series resistance of the phase inductors. Additionally, band-crossing information allows the fast detection of major changes in the current error, and the optimal system behavior decision, minimizing the transient time. Furthermore, the current control is stable in the complete duty cycle range, which is evaluated by means of a small-signal model. Experimental tests on a low-scale four-phase buck converter validate the proposal.