A three-phase power converter for converting power between a power grid network and a battery (255) comprises a three-phase grid transformer (230), a three-phase switching converter (251) for coupling to a positive terminal of the battery, a first, second and third series inductors(Ls1, Ls2, Ls3) coupled between the three-phase grid transformer and the three-phase switching converter, a control circuit (262) configured for controlling a first, second and third phase differences between first, second and third time-periodical power grid voltage signals(Vs1, Vs, Vs3) provided by the grid transformer and first, second and third converter time-periodical voltage signals (Vc1, Vc2, Vc3)provided to the switching converter such that the first, second and third time- periodical power grid voltage signals(Vs1, Vs2, Vs3) and first, second and third converter time-periodical currents(Ic1, Ic2, Ic3) are in phase. The three-phase grid transformer provides electrical isolation between the power grid network and the batter
