Implementation of control and protection logics for a bidirectional DC/DC converter

Abstract

In this paper, a control strategy for a bidirectional DC/DC power converter is discussed, and the logics to guarantee the operation correctness in various operative modes and for safety requirements are considered. In Buck (or step- down) mode, a voltage PI regulator is proposed, whereas in Boost (or step-up) mode an inner current control loop is introduced to guarantee a more effective current tracking, and to avoid damages due to overcurrents. Furthermore, a Finite State Machine (FSM) approach has been adopted to model the converter behavior and, in particular, to describe the protection logics for both Buck and Boost working modes, along with a special configuration called “Buffer control”, easily described using the FSM approach as composition of states. Numerical simulations results and real measurements show the effectiveness of the control strategy combined with a FSM logic description, rising up as a flexible approach to control a power converter device and to define its behavior in a desired working mode, as for buffer control.