Precharge apparatus for power conversion system

Abstract

Power conversion systems, methods and precharge systems are disclosed to charge a DC bus capacitor, including thyristors and reverse diodes coupled in AC circuit paths between AC input lines and a rectifier, a precharge resistor coupled in one or more of the AC circuit paths, and a controller to turn all the thyristors off to allow the DC bus capacitor to charge through the precharge resistor, and to turn all the thyristors on when the DC bus voltage reaches a non-zero threshold value.

Description

technical field [0001] The subject matter disclosed herein relates to power conversion, and more particularly, to power converters and precharging methods and apparatus for power converters. Background technique [0002] During power-up of the active front-end rectifier, the DC bus capacitors and any input filter capacitors are charged. This pre-charging may cause high inrush currents, which may stress or degrade components of the power conversion system. Excessive inrush current flow can also trip the system's circuit breakers. Attempts to reduce pre-charge inrush current include using large contactors or circuit breakers, but this adds cost, size and weight to the conversion system. Some precharge circuits also include complex switching logic to precharge the DC bus capacitors and any filter capacitors. Contents of the invention [0003] Various aspects of the disclosure are summarized below to facilitate a basic understanding of the disclosure, where the summary is n...

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Problems solved by technology

Attempts to reduce pre-charge inrush current include using large contactors or circuit breakers, but this adds cost, size and weight to the conversion system

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