The project DC-bus for microgrid at HES-SO ValaisWallis is a full scale demonstrator where the main electrical components in a modern building, i.e. photovoltaic power sources, various consumers and distributed storage systems are directly connected to a common DC distribution system. This paper describes the specifically designed DC/DC converters with MPPT for individual PV panels and the bidirectional AC/DC interface to the LV AC distribution grid. A model of the controller in the frequency domain of the AC/DC inverter has been used to optimise the control coefficients, with focus on both DC bus stability and reduction of the current harmonics on the AC grid side. Realisation, a simulation model and tests results are presented.