To address the issue of brief power outages when trains pass through the neutral section, various automatic neutral section power suppliers have been investigated. However, the schemes in existing literature have two main problems: the converter has numerous bridge legs and large capacity, and only operates briefly during trains passing through the neutral section, remaining in standby and idle state for over 95% of the time. To solve these two problems, this article proposes a converter topology for an automatic neutral section power supplier based on a three-leg converter. The proposed topology has fewer bridge-leg counts and requires a smaller converter capacity. By simply adding an ac switch and an inductor, it functions as a railway power conditioner, utilizing the automatic neutral section power supplier's idle time on time-division basis to improve the traction power supply quality. This article provides a detailed analysis of the coupling relationship and decoupling control methods of the input and output of the proposed topology when used as an automatic neutral section power supplier, as well as the control logic when used as a railway power conditioner. The effectiveness of the proposed system has been verified by simulation results and the experimental results of a down-scaled prototype.
