Compensating measurement delays in decoupling blocks of dq control technique for multiple active bridge converter

Multiple port DC/DC converters have applications such as hybrid energy storage systems, DC microgrids and multi-level and multi-modular inverters which need multiple DC sources. This paper analyzes the control loops of an isolated multiport converter, the multiple active bridge converter, using the first harmonic approximation and the dq-decomposition at switching frequency. This allows using decoupling blocks which aid for controlling the power flows independently. However, as the measurements provided to the decoupling blocks are delayed by the filters in the acquisition system, this can lead to decreasing or even violation of the stability margins. This paper is focused in the analysis and design of such control loops in order to eliminate the effect of the measurement filters on the decoupling blocks. For that, the paper proposed a feed-forward technique with compensators which improve the stability of the converter without sacrificing the time response. The method is validated through extensive simulations.

I. Introduction

Many applications need a multi-port converter, such as hybrid energy storage systems [1], solid-state transformers, advanced balancing systems for supercapacitors or batteries [2], [3], and renewable systems. For example, in photovoltaic (PV) applications, a three-port converter is useful to share the energy between the PV panels, a battery, and a DC grid [4], and also in applications related to electric vehicle chargers [5].