Multiport DC-DC autotransformer and methods for controlling and using the same

摘要

A multiport DC-DC autotransformer for interconnecting three or more DC systems. The autotransformer includes 2N−1 converters sequentially connected in series at a DC side, and connected to an AC transmission line via an AC link at an AC side, and a positive terminal of the i^th converter of the 2N−1 sequentially connected converters and a negative terminal of the (2N−i)^th converter are respectively connected to a positive terminal of the i^th DC system and a negative terminal thereof, where N represents the number of DC systems, and i represents the serial number of converters. Also disclosed are a method for determining power rating of each converter of the multiport DC-DC autotransformer, and a method for controlling the autotransformer. Most power can be transferred between different DC systems via a direct electrical connection without DC-AC-DC conversion.