Cascaded Dual-Active Bridge Cell Based Partial Power Converter for Battery Emulation

Abstract

Battery emulators provide a method for examining various aspects of control algorithms and power interfacing converters used in applications such as AC/DC micro-grids, electric vehicle power train, battery cell balancing circuit and control, battery storage energy management system design, etc. Many of these applications can not afford the down time caused by recharging of batteries hence the testers usually keep an additional set of charged batteries, increasing the cost further. Due to non-linearities within battery chemistries and due to charge/discharge effects, two sets of batteries can no longer be considered identical. Additionally, actual batteries have extremely strict safety requirements that have to be fulfilled. To alleviate some of these issues, a battery emulator has been proposed in this paper to replicate the electrical characteristics of a battery. The emulator is designed using a partial power processing (input-parallel, output-series) approach such that high efficiency and low control effort is achieved by utilizing a dual-active bridge (DAB) cell which is sized to less than 40% of overall power needed.