Study on the Coordinated Control Strategy of Wind Farm and VSC-HVDC

摘要

Offshore wind farms based on doubly fed induction generator (DFIG) are generally connected to the AC system via long submarine cables. Integration of offshore wind farms with HVDC transmission based on Voltage Source Converter (VSC-HVDC) is an advantage due to its regulating properties. This paper analyzes the need for coordinating the control of DFIG and VSC-HVDC link so that the two topologies can work together. Stator flux oriented vector control technology is used to execute AC excitation for DFIG rotor, then independent control of active and reactive power is realized and electricity generation by capturing maximal wind energy with high efficiency is also obtained. The control objective of VSC-HVDC is delivering the generated power to the AC network instantaneously and to keep AC voltage at wind farm bus constant. Interactions between DFIG and HVDC link are investigated and simulations performed in PSCAD/EMTDC to verify the proposed control strategy.