Operating characteristics of a new filter-commutated converter based on equivalent Graetz bridge circuit model

In this study, filter-commutated converter (FCC) with a new topological structure is proposed and compared with conventional high-voltage DC converters. The characteristic harmonic filters are installed at the tap of valve winding, which can implement the harmonic suppression and the reactive power compensation near the valve side. Based on multi-winding transformer theory and Kirchhoff´s law, the equivalent Graetz bridge model of the FCC is established, and the concept of a reactive power compensation factor at the valve side is introduced. Furthermore, the equivalent circuit of the DC side of the FCC is presented, and the influence of the compensation factor on the FCC characteristic parameters and the system-operating parameters are analysed in detail. Finally, a test on a prototyping system equipped with the FCC is performed to verify the correctness of the theoretical analysis of the FCC.