Distributed control strategy for a wind generation systems based on PMSG with uncontrolled rectifier HVDC connection

This paper presents a distributed control technique for voltage, frequency and active/reactive power control of the Point of Common Connection (PCC), AC grid, of a wind farm. Each wind turbine uses a Permanent Magnet Synchronous Generator (PMSG) with a full back-to-back VSI topology connected between the machine terminals and the PCC. A Diode-Thyristor converter topology forming a HVDC link is used for connecting the wind farm to the electricity network. The control strategy allows maximum power transfer from the wind turbines to the AC-grid, with good dynamic performance during steady state and transient operation of the AC-grid. Droop control strategies are used to regulate the voltage and frequency in the AC-grid respectively. The proposed control technique has been shown to be robust under load changes in islanded operation, capacitor bank switching, tracking of power reference and wind turbine reactive power distribution. The control technique has been validated with PSIM simulations of the system.