A push-pull DC autotransformer

Abstract

The invention discloses a push-pull DC autotransformer, which includes first, second and third power exchange units and positive and negative four-winding transformers, wherein the positive two ports of the first power exchange unit are connected to the positive pole of the second DC system The two negative ports of the first power exchange unit are connected to the two positive ports of the second power exchange unit through the positive four-winding transformer, and the two positive ports of the third power exchange unit are connected to the second power exchange unit through the negative four-winding transformer. The two ports of the negative pole of the exchange unit are connected, the positive poles of the four-winding transformer windings 1 and 2, the negative poles of the windings 3 and 4, and the positive pole of the first DC system are interconnected together, and the negative poles of the four-winding transformer windings 1 and 2 are interconnected. , the positive poles of the third and fourth windings, and the negative pole of the first DC system are interconnected together. The converter of the invention adopts the DC auto-coupling technology, which significantly reduces the commutation capacity, operation loss and total cost of the system.

Description

technical field [0001] The invention belongs to the technical field of power system power transmission and distribution, and more particularly, relates to a push-pull DC autotransformer. Background technique [0002] With the rapid development of new energy power generation, High Voltage Direct Current Transmission (HVDC) technology has received extensive attention and research from the society, and many HVDC transmission lines have been constructed and operated around the world. At the same time, with the maturity of flexible DC transmission technology and the successful trial operation of multi-terminal DC transmission systems, the technical feasibility and advantages of building a DC power grid by interconnecting different DC transmission systems are becoming more and more obvious. Large-capacity and multi-voltage levels are one of the future development trends of DC power grids, and DC transformers (or DC-DC converters), as an indispensable key technical equipment for in...

AI Technical Summary

Problems solved by technology

First, the rated capacity of the two converters must be equal to the rated DC power of the interconnection between the first DC system and the second DC system, and the rated DC voltage of the converters must be equal to the rated voltage of the connected DC system. higher overall cost

Secondly, all the transmitted DC power needs to go through DC / AC / DC two-stage power conversion, which results in large operating loss and low transmission efficiency.

[0006] To sum up, the existing mainstream high-voltage high-power DC transformers have at least one of the following defects, such as complex control strategies, high cost, high operating loss, and low transmission efficiency.

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