(19)

(11)

EP 2 332 228 A1

(12)

(43) Date of publication: 15.06.2011 Bulletin 2011/24 (21) Application number: 08803723.9 (22) Date of filing: 05.09.2008

(51) International Patent Classification (IPC):  H02J 3/06(2006.01) H02J 3/22(2006.01) (86) International application number: PCT/EP2008/061754 (87) International publication number: WO 2010/025771 (11.03.2010 Gazette 2010/10)

(84) Designated Contracting States: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MT NL NO PL PT RO SE SI SK TR Designated Extension States: AL BA MK RS (71) Applicant: ABB Research Ltd 8050 Zürich (CH)	(72) Inventor: THORBURN, Stefan S-723 48 Västerås (SE) (74) Representative: Tarkpea, Pia  ABB AB Intellectual Property Ingenjör Bååths Gata 11 721 83 Västerås 721 83 Västerås (SE)