Control of an Off-Shore Synchronous Generator Based Wind Farm with Uncontrolled Rectifier HVDC Connection

Large off-shore wind farms based on synchronous generators can be connected to the mainland grid using modern wind turbines allow for tight control of terminal voltage. Therefore, an integrated design of wind turbine and HVDC link control can lead to a substantial simplification of the off-shore rectifier. This paper introduces an integrated control algorithm for line commutated thyristor (LCT) based HVDC transmission line whereby the off-shore rectifier tap changer is eliminated and a cheaper and more efficient uncontrolled rectifier is used instead of a LCT-based rectifier. The presented control strategy allows for off-shore ac-grid voltage and frequency control and shows good performance during steady state and transient operation, including on-shore fault ride-through operation.