A Low Distortion PWM DC-AC Inverter, with Active Current and Voltage Control, Allowing Line-Interfaced and Stand-Alone Photovoltaic Applications

The energy transfer between a photovoltaic solar panel and the grid can be realized by means of a DC-AC inverter, which is described in this paper. A reliability study of the entire system (i.e. the solar panels and the inverter) shows that the voltage generated by the solar panel matrix has to be low (≪ 100 V). The stability conditions of the energy transfer dictate a current source behaviour of the inverter. This is realized by means of an appropriate feedback system. In this way a voltage inverter type can be used instead of the current inverters which are usually proposed, so the relatively heavy and expensive inductors can be omitted. This also allows the inverter to be used as an AC voltage power supply, in the absence of the power grid.