Analysis of a H-NPC topology for an AC traction front-end converter

In this paper a H-NPC topology is analyzed as the front-end converter at an AC traction application. These converters permit to achieve higher voltage levels and better current quality spectra than conventional single-phase H-bridge converters. The objective here is to analyze the suitability of main modulation strategies for traction applications, and to study the design requirements of current and voltage control loops for this kind of applications. Presented control and modulation loops have been tested in simulation and have been verified experimentally in a prototype test bench, showing the appropriateness of the proposed converter topology and control structures.