Extinguishing thyristors of railway or industrial power converter - using self-commutating rectifier across AC voltage terminals of main rectifier

摘要

Static power converter main branch thyristor extinction is based on using a circuit configuration including a self-commutating rectifier (2) in parallel with the a.c. voltage terminals of the main static power rectifier. The self-commutating rectifier (2) is modulated with d.c. voltage (giving a reactive power rectifier) and connected across the main rectifier a.c. voltage terminals in order to compensate the reactive (wattless) power. The polarity of the common a.c. input voltage is then determined by the reactive power rectifier bridge (2) and functions as the commutation voltage for the main rectifier's thyristors (T1-T4). ADVANTAGE - Optimum power factor in feeding d.c. intermediate circuit (d.c. link reactor) from a.c. voltage mains.