Charging system for electric vehicles
A charging system for electric vehicles includes a line interphase transformer, LIT-based rectifier configured for connecting an input of the LIT-based rectifier to an AC medium-voltage power signal and for outputting a medium-voltage DC-signal; a modular DC/AC converter with large step-down gain is configured for transforming the medium-voltage DC-signal into a medium-voltage HF-AC-signal; and a medium-frequency transformer, MFT, is configured for transforming the medium-voltage HF-AC-signal into a low-voltage HF-AC-signal for the at least one charging box.
1 . A charging system configured for delivering a low voltage power signal to at least one charging box for charging electric vehicles, the charging system comprising:
a line interphase transformer (LIT)-based rectifier, configured for connecting an input of the LIT-based rectifier to an AC medium-voltage power signal and for outputting a medium-voltage DC-signal;
a modular direct current to alternating current (DC/AC) converter with large step-down gain configured for transforming the medium-voltage DC-signal into a medium-voltage HF-AC-signal; and
a medium-frequency transformer (MFT) configured for transforming the medium-voltage HF-AC-signal into a low-voltage HF-AC-signal for the at least one charging box.
2 . The charging system according to claim 1 , further comprising an inductor configured for a filtering connection between each phase of the AC medium-voltage power signal and each input of the LIT-based rectifier.
3 . The charging system according to claim 1 , wherein the LIT-based rectifier comprises a multi-pulse LIT with a pulse number of 12, of 18, of 24, or of higher than 24.
4 . The charging system according to claim 1 , wherein the LIT-based rectifier comprises a LIT and a multi-pulse diode rectifier.
5 . The charging system according to claim 4 , wherein each one of the diodes of the multi-pulse diode rectifier is realized as a thyristor.
6 . The charging system according to claim 1 , further comprising a plurality of charging boxes, each one of the plurality of charging boxes comprising:
a low-voltage MFT,
a low-voltage AC/DC-converter, and
a charging pole for charging electric vehicles.
7 . A method for transforming an AC medium-voltage power signal into a low voltage power signal for at least one charging box for charging electric vehicles, the method comprising:
providing the AC medium-voltage power signal;
transforming, by utilizing a LIT-based rectifier, the AC medium-voltage power signal into a medium-voltage DC-signal;
transforming the medium-voltage DC-signal into a HF-AC medium-voltage signal; and
transforming, by utilizing a medium-frequency transformer, MFT, the HF AC medium-voltage signal into the low-voltage power signal;
wherein the low-voltage power signal is an HF-AC signal and is configured to serve as a low voltage power signal for at least one charging box.
8 . The method according to claim 7 , further comprising filtering, by utilizing an inductor, each phase of the AC medium-voltage power signal from each input of the LIT-based rectifier.
9 . The method of claim 7 , wherein the low-voltage HF-AC-signal is connected to a DC voltage bus for low-voltage power distribution.
10 . The method of claim 7 , wherein the low-voltage HF-AC-signal is connected to an AC/DC transformer that outputs the LV DC signal to the DC voltage bus.
11 . The charging system according to claim 1 , wherein the LIT-based rectifier comprises a line-side interphase transformer, whose outputs are fed to a multi-pulse diode rectifier.
12 . The method of claim 7 , wherein the LIT-based rectifier comprises a line-side interphase transformer, whose outputs are fed to a multi-pulse diode rectifier.