TRANSFORMERLESS INVERTER HAVING A DC/DC CONVERTER

摘要

A transformerless inverter (1), which serves to feed electricity from a DC current source (2) into an AC power grid (4), has an inverter bridge (10) and a DC/DC converter (5) connected upstream of the inverter bridge (10) and converts an input DC voltage (UE) that is present between two input lines (6 and 7) of the inverter (1) into a DC link voltage (UZ) present between two input lines (8 and 9) of the inverter bridge. The inverter bridge (10) converts the DC link voltage (UZ) present at the input lines (8 and 9) thereof into an output AC voltage. The DC/DC converter (5) comprises at least one resonant circuit (12) which has a resonance inductance (Lr1) and a resonance capacitance (Cr1) and can be connected in an electrically conductive manner on the input side by way of at least two clocked switches (S1, S2) to one of the two input lines (6 and 7) of the inverter or an intermediate potential line carrying a potential in between, and wherein the input lines (6 and 7) of the inverter into the input lines (8 and 9) of the inverter bridge (10) are galvanically isolated from one another by a capacitive method. The resonant circuit (12) is undivided and can be electrically conductively connected alternately to the two input lines (8 and 9) of the inverter bridge (10).