A novel average current-mode controller based optimal battery charger for automotive applications

This paper presents an average current-mode controller with a feedback clamp circuit based optimal bidirectional battery charger for automotive applications. The proposed controller forces the converter to work as a controlled current source when the battery state-of-charge (SOC) is below a predefined reference level and automatically reverts to controlled voltage source when the battery SOC exceeds the predefined reference level. The controller avoids the use of independent voltage and current loops and extra switching circuits to achieve current clamping in the proposed implementation is not based on saturation of the error amplifier, it is alway feedback controlled and the transition between constant current to constant voltage mode is smooth. The proposed implementation adapts well to Reflex™ charging technique. Experimental and simulation results are presented to verify the proposed algorithm.