To　stabilize　voltage　and　frequency　in　islanded　microgrid,　virtual　synchronous　generator　(VSG)　control　is　implemented　in　three-phase　four-leg　inverter.　However,　in　the　presence　of　unbalanced　loads,　the　conventional　VSG　control　strategy　can　result　in　unbalanced　voltage,　which　degrade　the　quality　of　the　power　supply　in　the　microgrid.　This　paper　proposes　an　unbalanced　voltage　compensation　method　for　VSG　in　islanded　microgrid　under　unbalanced　load　conditions.　The　EL　model　of　the　three-phase　four-leg　inverter　is　developed　in　the　dq0-coordinate　frame,　and　the　output　characteristics　of　the　VSG　under　unbalanced　load　conditions　are　analyzed.　The　unbalanced　voltage　caused　by　negative　and　zero-sequence　currents　can　be　mitigated　by　designing　virtual　impedances　for　the　negative　and　zero　sequences.　Meanwhile,　the　underlying　control　strategy　of　the　traditional　VSG　is　improved　by　introducing　dual　closed-loop　control　method　based　on　proportional-integral-resonance　and　passivity-based　control　(PIR-PBC)　hybrid　controller.　This　method　ensures　rapid　tracking　of　the　inverter＇s　output　voltage　reference　and　enhances　both　the　dynamic　performance　and　stability　of　the　system.　The　effectiveness　and　accuracy　of　the　proposed　control　strategy　are　verified　through　MATLAB/Simulink　simulation.　©　2025　IEEE.