The present invention relates to a power converter architecture and its operation principle that supplies an electric load with a controlled direct voltage from both a local direct current electricity source as well as an alternating current (AC) mains with maximum power conversion efficiency. For the case that the local electricity source can not provide enough electricity to the local load it is additionally supplied with electricity from the AC mains. In other case electricity is also feed into the AC grid when a local source can provide more electricity than needed to supply local loads.