Electrical circuit for zero voltage soft switching in a DC converter

摘要

An electrical circuit (100) for zero-voltage switching of a DC voltage converter under all load conditions has an n-port m-phase active bridge converter (10) with n≥2 and m≥3, each port ( 1, .., n) can be operated as an input or output port, each of the n ports (1, .., n) m phase branches (16) with a plurality of active switches (17, 19) with snubber or resonance switches connected in parallel. (C, C) has capacitors, the ports being able to convert a DC voltage (U, U) into an AC voltage and vice versa, the ports (1) using an m-phase transformer (25) or using m separate Transformers (25) are connected, each connected to each of the m phase branches (16) of each of the n ports (1, .., n) in order to transmit power between the ports (1, .., n), wherein an auxiliary circuit (110) is connected to a star point (S) of the transformers (25) to convert part of the transformer input voltage and energy into a D C center capacitor (C) of a DC intermediate circuit attributable to at least one of the n-port m-phase active bridge capacitors (10) in such a way that the DC center capacitor (C) has an offset voltage above and at its port is charged under the DC intermediate circuit center voltage (V), which enables the auxiliary circuit to provide a zero-voltage soft-switching operation of the switches (17, 19) of the converter phase branches (16) under all load conditions ,