Embedded impedance based state-of-charge estimation

Estimating the battery state-of-charge is an important aspect of prolonging battery life and optimizing discharge cycles. In this thesis, a hybrid method for estimating state-of-charge for lead-acid batteries is developed and implemented in a motor controller. The method uses a combination of impeda...

Full description

Bibliographic Details
Main Author: Boman, Carl
Format: Others
Language:English
Published: KTH, Maskinkonstruktion (Inst.) 2014
Online Access:http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-177673
Description
Summary:Estimating the battery state-of-charge is an important aspect of prolonging battery life and optimizing discharge cycles. In this thesis, a hybrid method for estimating state-of-charge for lead-acid batteries is developed and implemented in a motor controller. The method uses a combination of impedance measurements and a linear regression model for estimation. Measurements are done at stand-still. The method does not require sensors that are external to the motor controller or auxiliary battery connections other than terminal connections. The final estimation model shows good results but exhibits a slight ambient temperature dependence. === Att estimera ett batteris laddstatus är av stor vikt när det gäller att förlänga livslängden hos batteriet och att optimera urladdningscykler. I detta examensarbete utvecklades en hybridmetod för laddstatusestimering som sedan implementerades i en motorstyrning. Metoden använder en kombination av impedansmätningar och en linjär regressionsmodell för estimering. Mätningar görs vid stillastående. Metoden kräver inga externa sensorer eller andra batterianslutningar än terminalanslutningarna. Den slutgiltiga modellen uppvisar god prestanda men uppvisar ett visst temperaturberoende.