ALL-DC Offshore Wind Farm With Series-Connected Wind Turbines to Overcome Unequal Wind Speeds

This paper proposes a novel topology of voltage balance circuit for ALL-DC offshore wind farm with series-connected wind turbine. In the proposed topology, adjacent wind turbines are connected by a voltage balance circuit in parallel, and these wind turbines can achieve both the maximum power point tracking and balance the terminal voltages when the wind speeds of wind turbines are unequal. With the current compensation of voltage balance circuit, this topology can ensure the normal operation of wind farm even if some wind turbines are outage. Furthermore, the double loop controller for the voltage balance circuit is designed, which does not require the communication among wind turbines, and the stability analysis is implemented and discussed for tuning the control parameters. The simulation model and the RT-Lab experiment are set up to verify the validity of the proposed topology under unequal wind speeds. Simulation and experiment results confirm the superior performance of the proposed topology with low costs, high fault tolerance, and high efficiency.