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

Abstract

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 offshore 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 ultra-high 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 tolerance 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.

Balancing of Common DC-Bus Parallel Connected Modular Inductive Power Transfer Systems

“…Series-series topology is selected since the resonant frequency is independent of coupling and electrical loading. To further increase the reliability a modular structure is selected [16], [17]. This way during a single Rx module open circuit fault, the power transfer without over-loading the Tx side is possible.…”

Modular Multi-Port Ultra-High Power Level Power Converter Integrated with Energy Storage for High Voltage Direct Current (HVDC) Transmission

“…However, the battery cells are series connected to achieve a high voltage level, which requires BMS for them, resulting in high complexity [27]. Alternatively, the batteries cells can be decentralized into each submodule of multi-module converters [28,29] so that the distributed control of battery cells is achieved, and the BMS among isolated battery modules can be eliminated.…”