An Investigation into Thyristor-based Seven-level Multi-level Current Reinjection Current Source Converter

Abstract

This article presents a comprehensive analysis of the thyristor based seven-level multi-level current reinjection current source converter. The seven-level multi-level current reinjection current source converter increases the pulse number from 12 to 72, thereby producing high-quality AC current and DC voltage waveforms, thus lowering harmonics on both sides. The ability to switch thyristors with a negative firing angle using auxiliary bridge reinjection insulated-gate bipolar transistors enables the converter to have a leading power factor. This article also details the design of the firing angle controller for the seven-level multi-level current reinjection current source converter, which enables the converter to have a negative firing angle. A wide range of PSCAD/EMTDC simulation results are presented to evaluate the performance of this converter, especially the effect of RC snubbers across the reinjection insulated-gate bipolar transistors.

Keywords:

• AC-DC conversion
• current source conversion
• harmonics
• HVDC