Direct Resonant Control Strategy for Torque Ripple Mitigation of DFIG Connected to DC Link through Diode Rectifier on Stator

Abstract

This paper presents a torque ripple mitigation method for the doubly-fed Induction generator (DFIG) connected to the dc link through a diode rectifier on the stator winding. A resonant regulator based on torque compensator is directly added to the conventional rotor current control loop, and the sequential separations and calculations of rotor harmonic current references can be avoided. Then, a novel stator flux orientation method is achieved by indirectly controlling the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">q</i> -axis stator flux linkage to be zero without calculating the stator flux linkage angle. The stator frequency is controlled by regulating the stator flux without calculating the stator frequency. Based on a mathematical model of the DFIG control system, the effects on system stability using the resonant controller, analysis of the steady-state error, and the dynamic performance are discussed. Finally, the proposed control method is validated by the experiment results.