Circuit arrangement for the reliable switching of electrical circuits

Abstract

A circuit arrangement for the reliable switching of electrical circuits comprises two longitudinal branches (12), with two switching elements (11,12) arranged parallel to each other in one of the branches, the switch inputs (20) of which are connected to the input point (4,5) of the longitudinal branch and the switch outputs (21) of which are each connected to the input side of a winding (8,9) on a transformer (10).

Description

technical field [0001] To interrupt and close current circuits, not only mechanical contacts, such as sliding contacts in the brushes of rail vehicles or inverters in electric motors, fuses, but also semiconductors such as transistors, thyristors and semiconductor relays are used switch. Background technique [0002] When the current loop is interrupted, all these switching devices will experience a high self-induced voltage due to the rapid decrease of the stored inductive energy throughout the current loop. [0003] This self-induced voltage can heat and destroy semiconductor switching devices and protective circuits, cause material migration and welding on the contact surfaces, and can prevent the breaking of the current loop by forming an arc between the contact surfaces. [0004] When the current loop is closed, the capacitance present in the current loop is quickly charged, which temporarily leads to high inrush currents. [0005] This switching current causes materi...

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Problems solved by technology

However, this circuit has the disadvantage that the capacitor must be short-circuited or skip-charged when the switching device is closed, which causes high turn-on current, high switching losses, and severe welding of the switching device. Therefore, the capacitance of the capacitor is limited to very small values, which greatly limits its efficiency

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