Simulation Analysis of Low Voltage Traversal Characteristic on Crowbar-based Doubly-fed Generator

Due to its special circuit structure,the doubly-fed induction generator is very sensitive to voltage drop when connected in the grid.A common measure to ensure the traversal of doubly-fed induction generator at low voltage is to protect the circuit short-connected rotor through Crowbar,but the disadvantage of this measure lies in the fact that the doubly-fed generator operates in an asynchronous state and it has to draw on reactive power from the system to realize excitation.This paper first analyses the operation characteristic of the doubly-fed induction generator during the voltage drop.Then based on a summary of the traditional input and elimination control through Crowbar,it puts forward an improved input and elimination control.On MATLAB/Simulink platform a grid-connected doubly-fed wind farm model is put up where the improved input and elimination control is adopted and the traversal operation characteristic of the doubly-fed generator at low voltage is studied.The simulation analysis proves the effectiveness of the improved input and elimination control.