A Novel Decoupled Interconnecting Method for Current Source Converter Based Offshore Wind Farms

This paper presents a novel interconnecting approach for an offshore wind farm, where pulse width modulated (PWM) current-source converter(CSC) of each wind generator is series connected and dc output is fed by submarine cable to the series connected PWM CSCs on grid side. The total number of series connected PWM CSCs for the onshore grid connections are equal to the number of wind generators installed in the wind farm. The proposed interconnecting method enables simple topology for offshore wind farm without the need of an offshore central converter platform. The variable speed wind turbine driving permanent magnet synchronous generator (PMSG) is considered in this study. A new decoupled control scheme for independent active and reactive power control with variable dc link current regulation is developed for the grid side converter. The key feature of the control scheme is that minimized dc link current control is achieved without the use of long distance communication link. Simulation and experimental results are provided to verify the proposed control scheme.