Static　synchronous　generator　(SSG)　is　a　novel　facility　combining　static　synchronous　compensator　(STATCOM)　with　energy　storage　technique　for　flexible　alternative　current　transmission　systems　(FACTS).　This　paper　analyzes　the　basic　working　principle　of　the　system　and　then　proposes　a　new　control　scheme　for　realizing　state　of　charge　(SoC)　balancing.　Meanwhile,　in　order　to　achieve　better　dynamic　characteristics　of　capacitor　voltage　balancing,　the　conventional　capacitor　voltage　control　scheme　is　improved　by　introducing　feed-forward　of　SoC　deviations.　Simulation　results　verify　the　effectiveness　of　the　proposed　control　scheme.　©,　2015,　Power　System　Technology　Press.　All　right　reserved.