A dual thyristor converter reducing harmonics of power supply without input transformer

AbstractIn general, the thyristor‐controlled rectifier circuit (thyristor converter) generates a large amount of harmonics in the input power supply. Consequently, in the power system, the harmonics become more increased for larger capacity of such a converter, thus it is important to improve their harmonic characteristics. Among such converters, the double three‐phase bridge converter with transformer of star and delta windings is well known. By application of such techniques, Miyairi and his group proposed a thyristor converter which has excellent harmonic characteristics. On the other hand, the multiple‐connected inverter circuit without output transformer had been already proposed. However, it contains the lower‐order harmonics.This paper proposes a converter which can reduce the harmonics similarly to the forementioned double‐bridge converter. This circuit has the center‐tapped reactor that can control the dc current like the current control of Miyairi's interphase reactor. This novel converter need not use the input three‐phase transformers that usually make the cost higher. The proposed circuit has a commutation one with capacitor that is analogous to the series diode‐type t