A bidirectional buffered charging unit for EV's is presented, allowing the charge with high power even if the line current capability is limited. The bidirectional buffer is connected to the AC line and is mainly dedicated to vehicles with on-board AC-DC chargers. Extensions are described for the integration of RES as well as for DC charging. The system is also dedicated to operate as a reactive power compensator, or to provide grid system services similar to V2G operation or other power smoothing functions.
At the side of the buffer battery, the system presented uses a bidirectional DC-DC converter which can be realized in different technologies. A conventional solution with three interleaved channels is compared with a fast switching converter using SiC components.