The application of multi frequency resonant controllers in in a dfig to improve performance by reducing unwanted power and torque pulsations and reducing current harmonics

Abstract

The paper describes a method to control the rotor-side and grid side converters in a DFIG when subjected to the effects of network voltage unbalance conditions. Multi Frequency Resonant Controllers are incorporated into the grid side and rotor side converters to assist in the control functions. The Resonant Controllers are tuned to twice the network frequency to assist in the control of power and torque pulsations and to three times the network frequency to assist in the control of the generated third harmonic currents. A DFIG model is implemented in Matlab/Simulink and simulations show the reduction in power and torque oscillations and a reduction in the 3rd harmonic currents generated as a result of the applied voltage unbalance.