Abstract: Some embodiments are directed to charging system (100) comprising converter switches for electrically coupling to a first electrical energy storage device, a filter circuit comprising a series inductor and a parallel capacitor, a coupling device for coupling to a second electrical energy storage device comprising a detection device for detecting a connection status of the coupling device, switches arranged for selectively electrically coupling, when switched on, the filter circuit with an alternating current voltage source, and a controller, configured, based on the connection status of the coupling device, to switch on switches and control the converter switches such that the time periodical voltage signal and the current through the series inductor are in phase, or to switch off switches and control the converter switches for providing a current signal to the second electrical energy storage device.

Abstract: Some embodiments are directed to a three-phase power converter for converting power between a power grid network and a battery that includes a three-phase grid transformer, a three-phase switching converter for coupling to a positive terminal of the battery, a first, second and third series inductors coupled between the three-phase grid transformer and the three-phase switching converter, a control circuit configured for controlling a first, second and third phase differences between first, second and third time-periodical power grid voltage signals provided by the grid transformer and first, second and third converter time-periodical voltage signals provided to the switching converter such that the first, second and third time-periodical power grid voltage signals and first, second and third converter time-periodical currents are in phase. The three-phase grid transformer provides electrical isolation between the power grid network and the battery.

Abstract: Some embodiments are directed to a three-phase power converter for converting power between a power grid network and a battery that includes a three-phase grid transformer, a three-phase switching converter for coupling to a positive terminal of the battery, a first, second and third series inductors coupled between the three-phase grid transformer and the three-phase switching converter, a control circuit configured for controlling a first, second and third phase differences between first, second and third time-periodical power grid voltage signals provided by the grid transformer and first, second and third converter time-periodical voltage signals provided to the switching converter such that the first, second and third time-periodical power grid voltage signals and first, second and third converter time-periodical currents are in phase. The three-phase grid transformer provides electrical isolation between the power grid network and the battery.