Design and implementation of a four-phase converter with digital current sharing control for battery charger

Abstract

This paper designs and implements a charger with high output current for EV batteries, the structure of the charger is formed of a four-phase interleaved buck converter with synchronous rectification and associated with the digital controller, in which the current sharing control is realized. The interleaved control scheme can reduce the output ripple and decrease the power component stress in battery charger application. In addition, synchronous rectification is utilized to improve power efficiency of the interleaved buck converter. This paper uses TMS32F28035 by TI as the digital controller to control the implemented four-phase buck converter to perform interleaved control, charging function and current sharing control. The specification of the used Yttrium Lithium battery is 20V/40Ah for experiments. The validity of the charger formed of the designed interleaved buck converter is conducted with the experiment results for constant current 40A output and the verification of current sharing control.