Electrical circuit with auxiliary voltage source for zero voltage switching in a DC converter under all load conditions

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≥1, each port ( 1, 2, ..., n) can be operated as an input or output port, each of the n ports (1, 2, ..., n) having m phase branches (16) with a plurality of active switches (17, 19) has parallel-connected snubber or resonance (C, C) capacitors, the n ports being able to convert a DC voltage (U, U) into an AC voltage and vice versa, the n ports (1, 2, ..., n) are connected via an m-phase transformer (25) or via m separate transformers (25) which are each connected to each of the m phase branches (16) of each of the n ports (1, 2, ..., n) to transmit power between the ports (1, 2, ..., n), with an auxiliary circuit (110) connected to the transformers (25) for a part of transformer input voltage and energy convert at least one of the n-port m-phase active bridge converters (10) in a DC center capacitor (C) of a DC link via an auxiliary voltage source (27) in order to recharge the DC center capacitor (C), thereby the auxiliary circuit is enabled to regulate the voltage of the center capacitor (C), whereby a zero-voltage soft switching operation of the switches (17, 19) of the converter phase branches (16) is provided under all load conditions.