Control strategy of a solar power inverter (analysis of a fifth order system-II)

To interface solar power inverter structures to the power grid mostly multi-stage filter structures are used for coupling and to fulfil EMI requirements. The resulting topology leads to a high system order, which is difficult to control and problematic to realize due to unknown, unpredictable mains impedance behavior. In this paper a conventional structure is analyzed in detail, giving hints to optimize the system and how to control it. Especially 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.