Transient Ride-Through Operation Of Wind Turbines With Full-Capacity Power Converters Under Grid Faults

With the increasing penetration of wind power, it has become a significant part of thepower system. The emergying grid codes are improving the fault ride-through requirements(FRT), which makes it necessary to improve the transient response of wind turbines undergrid faults. This thesis studies the transient controllability of wind turbines withfull-capacity power converters, and proposes novel control strategies to protect it fromtransient impacts.Voltage phase jump often occurs at the transient of grid faults. If the phase-locked loop(PLL) fails to capture the voltage phase immediately, wind turbines can not control activeand reactive power quickly, and even be damaged. This thesis introduces phase feedforwardinto the controller of grid-side converters, which helps it be oriented to the grid voltagevector immediately. The feasibility of the phase feedforward is analyzed in detail underboth balanced and unbalanced grid faults. The high voltage ride through ability of windturbines with full-capacity power converters is also inverstigated. The research results andanalysis are validated by simulation, which is carried out based on a2MW wind turbinewith full-capacity power converter in MALAB/SIMULINK.