Control strategy of a solar power inverter (analysis of a seventh order system)

Conventional structures of inverters use a multi-stage filter, required for grid coupling operation and to fulfill EMI requirements. The resulting topology leads to a high system order, which is difficult to control and problematic to realize due to unknown mains impedance behavior. In this paper a conventional structure is analyzed in detail, giving hints to optimize the system and to control it. The digital control method of the inverter is treated in detail. It is shown that the optimal adaptation of the presented structure leads to a simple, easy to use and very robust solution