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Combining electric vehicle battery charging and battery cell equalisation in one circuit

Lookup NU author(s): Huaxia Zhan, Dr Haimeng Wu, Dr Musbahu Muhammad, Dr Simon LambertORCiD, Professor Volker Pickert



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


Electric vehicles (EVs) require an onboard battery charger unit and a battery management system (BMS) unit that balances the voltage levels for each battery cell. So far, both units are two completely autarkic power electronics systems. The circuit presented here operates as a battery charger when the EV is connected to the grid and as a voltage balancer when the EV is driving. Thus, the proposed circuit utilises two functions in one and therefore eliminates the need of having two autarkic units reducing complexity and reduction in component count. The proposed circuit operates as a flyback converter and achieves power factor correction during battery charging. The constant-current constant-voltage (CC–CV) charging method is employed to charge the batteries. However, to limit the number of sensors that will be employed as a result of varying cells during charging, the battery current is estimated using a single current transducer and embedding a converter model in the controller. The operation of the circuit is presented in detail and is supported by simulation results. A laboratory prototype is built to verify the effectiveness of the proposed topology. Experiment results show that the proposed method provides an integrated solution of on-board charging and voltage equalisation.

Publication metadata

Author(s): Zhan H, Wu H, Muhammad M, Lambert S, Pickert V

Publication type: Article

Publication status: Published

Journal: IET Electrical Systems in Transportation

Year: 2021

Volume: 11

Issue: 4

Pages: 377-390

Print publication date: 09/12/2021

Online publication date: 23/06/2021

Acceptance date: 07/06/2021

Date deposited: 30/08/2021

ISSN (print): 2042-9738

ISSN (electronic): 2042-9746

Publisher: The Institution of Engineering and Technology


DOI: 10.1049/els2.12031


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