Online and On-Board Battery Impedance Estimation of Battery Cells, Modules or Packs in a Reconfigurable Battery System or Multilevel Inverter
Paper in proceeding, 2020

This paper shows two approaches to determine the battery impedance of battery cells or battery modules when used in a reconfigurable battery system (RBS) or in any type of modular multilevel converter (MMC) for electric drive applications. A generic battery model is used and the concepts of the recursive time and frequency-domain parameter extraction, using a current step and an electrochemical impedance spectroscopy, are explained. Thus, it is shown and demonstrated that the balancing current of neighboring cells/modules ,when in parallel operation, can be used, similar to the time-domain parameter extraction utilizing a current step, to determine the battery parameters. Furthermore, it is shown and demonstrated that a part of the inverter can be used as variable AC voltage source to control a sinusoidal current through the motor inductances of the drive train, which can be injected to the inserted battery cells/modules of an adjacent phase to perform an on-board impedance spectroscopy. Using either of the two presented approaches, the individual battery impedances can be easily determined, yielding the state of health (SOH) and the power capability of individual battery cells/modules. Nonetheless, the analyzed approaches were just considered to be applied at machine standstill, which is not suitable for grid-tied applications.

Parameter estimation

Multilevel systems

Electrochemical impedance spectroscopy


Modular multilevel converters


Anton Kersten

Chalmers, Electrical Engineering, Electric Power Engineering, Electrical Machines and Power Electronics

Manuel Kuder

Bundeswehr University Munich

Weiji Han

Chalmers, Electrical Engineering, Systems and control, Automatic Control

Torbjörn Thiringer

Chalmers, Electrical Engineering, Electric Power Engineering, Electrical Machines and Power Electronics

Anton Lesnicar

Bundeswehr University Munich

Thomas Weyh

Bundeswehr University Munich

Richard Eckerle

Bundeswehr University Munich

IECON Proceedings (Industrial Electronics Conference)

Vol. 2020-October 1884-1891 9254515

46th Annual Conference of the IEEE Industrial Electronics Society, IECON 2020
Virtual; online, Singapore,

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