Fault-Tolerant Converter With a Modular Structure for HVDC Power Transmitting Applications

作者:Hu, Yihua; Chen, Guipeng*; Liu, Yang; Jiang, Lin; Li, Peng; Finney, Stephen J.; Cao, Wenping; Chen, Huifeng
来源:IEEE Transactions on Industry Applications, 2017, 53(3): 2245-2256.
DOI:10.1109/TIA.2017.2657480

摘要

For the high-voltage direct-current (HVDC) power transmission system of offshore wind power, dc/dc converters are the potential solution to collect the power generated by off-shore wind farms to HVDC terminals. The converters operate with high-voltage gain, high efficiency, and fault tolerance over a wide range of operating conditions. In this paper, an isolated ultrahigh step-up dc/dc converter with a scalable modular structure is proposed for HVDC offshore wind power collection. A flyback-forward converter is employed as the power cell to form the expandable electrically isolated modular dc/dc converter. The duty ratio and phase-shift angle control are also developed for the proposed converter. Fault-tolerant characteristics of the converter are illustrated through the redundancy operation and fault-ride-through tests. Redundancy operation is designed to maintain high operation efficiency of the converters and fault-ride-through operation improves the converter reliability under harsh operating conditions. Analytical studies are carried out, and a 750-W prototype with three modular cells is built and experimentally tested to verify the performance of the proposed modular dc/dc converter.