Abstract:
This paper presents a sinusoidal current control scheme for the doubly fed induction generator (DFIG)-DC system to reduce the harmonic current losses of the stator and ro...View moreMetadata
Abstract:
This paper presents a sinusoidal current control scheme for the doubly fed induction generator (DFIG)-DC system to reduce the harmonic current losses of the stator and rotor windings. The DFIG-DC system can be controlled as an open-winding system if the DFIG is equivalent in the
Г
circuit. The stator is connected to the dc link through the diode bridge and the rotor is connected to the same dc link through the rotor-side converter. A phase-locked loop based on stator flux is applied for estimating not only the stator frequency but also the angle of stator flux linkage. The sinusoidal stator current can be achieved by injecting appropriate harmonic voltages to the rotor side. The rotor harmonic voltages are produced by applying the stator voltage directly without employing a series of resonant controllers. Since the voltage of the diode bridge depends on the direction of the flowing current, the stator voltage of DFIG can be expressed by the stator current avoiding the stator voltage sensors. In this way, the harmonic current losses of the stator and rotor windings can be greatly reduced, which is beneficial for system efficiency. Furthermore, the torque ripple and power ripple can also be reduced, which is a good operation condition of the DFIG-DC system. The proposed control method is validated through experiments.
Published in: IEEE Transactions on Industrial Electronics ( Volume: 65, Issue: 8, August 2018)