Model-Based Determination of Closed-Loop Input Impedance for Dual Active Bridge Converters


This study proposes a method of determining the input impedance of a phase shift modulated dual active bridge (DAB) converter in closed-loop operation. Input impedance is an important characterization of converter behavior, particularly in regards to interactions with external sources or systems. When converter models are available, model-based determinations of input impedance are possible through the application of the Extra Element Theorem (EET). However, DAB converters are not easily modeled using standard techniques due to their high-frequency ac stage. Instead, DAB models are derived using generalized average modeling (GAM). The GAM approach allows ac power stages to be modeled accurately but creates difficulties for model-based calculations of closed-loop impedances. This study simplifies determinations of closed-loop input impedance for DAB converters by deriving standalone expressions for the driving point impedances needed to apply the EET. These expressions allow the closed-loop input impedance to be calculated for any linear controller without the derivation of a corresponding closed-loop model. The values of input impedance calculated from these expressions are validated through comparison to experimental results from hardware tests.

Meeting Name

32nd Annual IEEE Applied Power Electronics Conference and Exposition (2017: Mar. 26-30, Tampa. FL)


Electrical and Computer Engineering

Research Center/Lab(s)

Intelligent Systems Center

Keywords and Phrases

Electric Impedance Measurement; Linear Control Systems; Power Converters; Power Electronics; Closed-Loop Operation; Driving Point Impedances; Dual Active Bridge Converter; Dual Active Bridges; Extra Element Theorem; Generalized Average Models; Linear Controllers; Phase Shift Modulation; Electric Impedance; Generalized Average Modeling; Impedance Criteria; Impedance; Mathematical Model; Transfer Functions; Integrated Circuit Modeling; Harmonic Analysis; Topology; Analytical Models

International Standard Book Number (ISBN)

978-1509053667; 978-1509053674

International Standard Serial Number (ISSN)


Document Type

Article - Conference proceedings

Document Version


File Type





© 2017 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Mar 2017