Novel Fault Ride-Through Configuration and Transient Management Scheme for Doubly-fed and Self-excited Induction Generators

Abstract

This thesis proposed a novel Fault Ride Through (FRT) configuration and transient management scheme to enhance the fault ride through capability of both doubly-fed induction generator (DFIG) and self-excited induction generator (SEIG) based wind turbines. The new configuration of the power electronics converter introduces shunt and series compensation for normal operation and voltage dips, respectively. To attain a flexible control solution for balanced and unbalanced fault conditions, the proposed transient management scheme employs positive and negative sequence controllers. For DFIGs, a small-signal linear model is developed and examined to analyze the system dynamics for the series compensation topology. Based on the mathematical model, the controller is tuned to balance both voltage regulation performance and transient stability margins with consideration of various operating conditions. For SEIGs, an active damping control loop for the shunt compensation configuration is developed to mitigate system oscillation and improve system performance in slight grid disturbances; the decouple control method is utilized to regulate the series voltage injection during severe faults. The combination of shunt and series interfaces demonstrates a low component count, simple protection structure, and improved performance of fault ride through with effective compensation to the electric grid. A comprehensive simulation verified the capability of the new configuration and transient management scheme. The experimental results demonstrate the effectiveness of the proposed shunt-series reconfiguration topology for maintaining the load voltage to its pre-fault magnitude during severe voltage dips.

Date of Award	Jun 2013
Original language	American English
Supervisor	Michael Weidong Xiao (Supervisor)