High-Frequency Resonance Damping of DFIG-Based Wind Power System Under Weak Network

Abstract

When operating in a micro or weak grid which has a relatively large network impedance, the Doubly Fed Induction Generator (DFIG) based wind power generation system is prone to suffer high frequency resonance due to the impedance interaction between DFIG system and the parallel compensated network (series RL + shunt C). In order to improve the performance of the DFIG system as well as other units and loads connected to the weak grid, the high frequency resonance needs to be effectively damped. In this paper, the proposed active damping control strategy is able to implement effective damping either in the Rotor Side Converter (RSC) or in the Grid Side Converter (GSC), through the introduction of virtual positive capacitor or virtual negative inductor to reshape the DFIG system impedance and mitigate the high frequency resonance. A detailed theoretical explanation on the virtual positive capacitor or virtual negative inductor has been given, and their parameters are also optimally designed. The proposed DFIG system damping control strategy has been validated by experimental results.Index Terms -DFIG system impedance; series RL + shunt C network; high frequency resonance damping; virtual positive capacitor; virtual negative inductor.The authors are with the

Harmonic Modelling of the Wind Turbine Induction Generator for Dynamic Analysis of Power Quality

“…Applying the dynamic harmonic domain methodology to Equation (8), and then applying a numerical integration rule, the companion harmonic circuit model in the Norton equivalent form is obtained as shown in Equation (9). The detailed procedure of the development of the CHCM of the induction machine is presented in Appendix A.…”

“…Notice that the time-varying nature of the complex matrix Y I M is due to the rotor angular position, and the variables for the stator and rotor are all included in Equation (9). A graphical representation of the CHCM for the induction machine is shown in Figure 1, where the phase inductances and sources are given by the time-varying complex inductance matrix Y I M , and the harmonic current source hist I M , respectively.…”

Active damping of resonances in DFIG system with cascade converter under weak grid

“…The subsynchronous resonance (SSR) [15‐32] and the high‐frequency resonance (HFR) [33]‐ occurs in series‐compensated, and parallel‐compensated grids, respectively, due to the interaction of impedance of weak grid with the DFIG system.…”

“…Likewise, the HFR in the DFIG system is also studied under weak grid . The impedance characteristics of the DFIG system have been well investigated in Song et al However, the author did not propose any damping technique to mitigate potential HFR.…”

“…The impedance characteristics of the DFIG system have been well investigated in Song et al However, the author did not propose any damping technique to mitigate potential HFR. To actively damp the HFR, Song and Blaabjerg introduced the virtual impedance in RSC or GSC. By reshaping the DFIG impedance, the SSR and HFR in the DFIG system can be mitigated.…”