A　generalized　control　algorithm　was　proposed　for　the　grid-connected　inverter　control　system　of　energy　storage　(ES)　to　realize　the　grid-connected/islanded　smooth　transition　of　microgrid.　Based　on　the　inverter＇s　hierarchical　control　structure,　the　part　of　ES　system＇s　transmission　function　was　unitized　by　using　the　two　degrees　of　freedom＇s　control　principle　and　inverse　model　of　controlled　objects.　Then,　the　control　layer　architectural　difference　of　ES　grid-connected　inverter　was　removed　in　the　different　operation　modes　of　microgrid　and　the　output　current　dynamic　disturbance　full　compensation　of　ES　was　realized　by　the　proposed　control　algorithm.　For　the　application　layer　of　ES　control　system,　because　of　the　transmission　function　unitization,　the　dynamic　full　compensation　of　the　grid　voltage　harmful　disturbance　quantity　can　be　implemented　when　the　PQ　control　mode　was　adopted　by　ES　control　system;　under　island　mode,　when　the　droop　control　mode　was　adopted,　the　voltage　and　frequency　fluctuation　of　microgrid　was　suppressed　and　the　harmful　disturbance　currents　from　distributed　generation　(DG)　and　loads　were　eliminated,　by　introducing　the　voltage　and　frequency　feed　forward　compensations.　Meanwhile,　the　control　layer＇s　generalized　structure　can　help　the　microgrid　to　avoid　transient　oscillation　in　the　switching　process,　and　then　the　influences　on　DG　and　the　sensitive　load　can　be　weakened.　Therefore,　the　seamless　switching　purpose　can　be　realized.　To　further　verify　the　correctness　and　validity　of　the　proposed　control　algorithm,　the　microgrid　simulation　platform　was　established　by　using　MATLAB/Simulink,　and　the　simulation　results　of　microgrid＇s　planned　and　unplanned　operation　mode　switching　were　carried　out.　©　2019　Chin.　Soc.　for　Elec.　Eng.