Method for operating an inverter having reactive power capability and having an unfolding bridge, and inverter having reactive power capability and having an unfolding bridge

摘要

A method for operating an inverter with reactive power capability that includes a voltage link circuit and an unfolding bridge, wherein poles of the voltage link circuit are configured to be selectively connected to terminals of an AC output in different configurations by means of the unfolding bridge, in order to change a polarity of the AC output relative to the voltage link circuit. The method includes in the case of a phase shift between an AC current (I) and an AC voltage (U) at the AC output reversing the direction of a current flowing via the voltage link circuit. Reversing the direction of the current flowing via the voltage link circuit includes disconnecting the AC output from the voltage link circuit, providing a freewheeling path between the terminals of the AC output, while the AC output is disconnected from the voltage link circuit, and reconnecting the AC output to the voltage link circuit with the polarity of the AC output relative to the voltage link circuit being changed by the unfolding bridge.