This　article　presents　an　improved　linear-quadratic　regulator　(LQR)　control　based　on　linear　matrix　inequalities　(LMIs)　to　optimize　the　key　parameters　for　the　closed-loop　control　of　dual-active-bridge　(DAB)　converters　with　high　system　uncertainty.　First,　the　polytopic　model　of　an　uncertain　DAB　converter　is　introduced　according　to　the　simplified　DAB　equivalent　circuit.　LMIs　are　then　used　in　the　improved　LQR　control　to　derive　the　optimized　control　parameters　under　the　given　constraints.　An　improved　LMI-LQR　hybrid　closed-loop　control　is　adopted　with　the　output　current　introduced　in　the　control　loop　to　enhance　the　dynamic　performance.　The　performance　of　the　proposed　LMI-LQR　is　compared　with　the　conventional　LQR　in　terms　of　transient　responses　under　various　load　and　line　disturbances.　Both　the　simulation　and　experimental　results　are　provided　to　validate　the　advantages　of　the　proposed　control.　©　2020　IEEE.