Single-phase　voltage　source　inverter　(VSI)　still　suffers　a　long　settling　time,　and　significant　voltage　overshoot/undershoot　under　the　sudden　output　current　change　such　as　the　impact　load　application.　This　paper　first　built　the　system　differential　equation　to　model　and　analyzed　this　comprehensive　large　signal　dynamic　process.　And　then　presents　a　hardware-efficient　digital　control　algorithm,　as　the　improved　capacitor　charge　balance　control　(CBC),　forces　the　inductor　current　and　capacitor　voltage　reach　the　target　value　by　accurately　tracking　the　predicted　optimal　trajectory　during　the　transient　process.　A　linear　PI　regulator　is　also　employed　under　the　steady-state.　For　the　given　main　circuit　parameters　and　detected　load　step　change,　the　detailed　mathematical　derivation　and　design　procedure　are　provided　to　guide　the　implementation.　Finally,　simulation　and　experimental　results　verify　single-phase　VSI　attain　the　significant　settling　time　reduction　and　minimized　voltage　variations.　Fast　load　adjustment　can　be　achieved　without　the　consideration　of　control　bandwidth　limitation,　like　the　conventional　linear　regulator　under　wide　load　range　operation.　©　2020　IEEE.