Surge limiter for a traction power converter

Abstract

The invention relates to a device (2) for limiting an overvoltage in the DC link (18) of a traction power converter. The inventive device (2) comprises two interruptible semiconductor switches (T7, T8) that are electrically connected in series, an inductor (48), a double-layer capacitor (50), and a resistor (54) which can be connected by means of a switch (S1). The inductor (48) and the double-layer capacitor (50) are electrically connected in series while said series connection is connected between an interconnection point (46) of the two interruptible semiconductor switches (T7, T8) and a negative conductor rail (20) of the DC link (18). Additionally, the connectable resistor (54) can be electrically connected parallel to the double-layer capacitor (50), resulting in a device which is structured in a particularly simple manner and by means of which overvoltages occurring in the DC link (18) of a traction power converter can be suppressed.

Description

technical field [0001] The invention relates to a device for limiting overvoltages in the intermediate circuit of a traction rectifier. Background technique [0002] Traction rectifiers, in particular traction rectifiers for diesel locomotives, usually have a pulse inverter which feeds at least one induction machine, especially an asynchronous machine. During driving, power is extracted from the energy supply network, in particular a railway network, and transmitted to the induction motor by means of a pulse inverter. The power flow is reversed during electric braking operation. Since the railway network cannot receive braking energy at every moment, an additional device for dissipating braking energy must be installed in the intermediate circuit. [0003] Furthermore, in the intermediate circuit of the traction rectifier there is provided a device for limiting the overcurrent which is primarily required to protect the pulsed inverter. Rapid overvoltages which arise, for ...

AI Technical Summary

Problems solved by technology

[0008] 1. Destructive, electrolyte-decomposing processes that occur when a special "maximum operating voltage" is exceeded

[0009] 2. Due to manufacturing tolerances, double layer capacitors of the same type may have different self-discharge and different internal resistance

As a result, when double-layer capacitors are connected in series, a mutual drift of the operating voltage of the double-layer capacitors occurs already after only a few charging cycles, which during charging can result in exceeding the specific "maximum operating voltage" of the individual double-layer capacitors and The resulting damage to the double layer capacitor

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