Modeling and Coordinated Control Design for Brushless Doubly-Fed Induction Generator-Based Wind Turbine to Withstand Grid Voltage Unbalance

Abstract

Grid codes require wind turbines to have capability to withstand a certain grid voltage unbalance without tripping. However, existing controls for brushless doubly-fed induction generator (BDFIG) based wind turbine under grid unbalance have many problems such as difficulty in realizing decoupling control, involvement with flux or current estimations, and complex control structure. Moreover, the existing studies only focused on the control of machine side converter (MSC), but the coordinated This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.

A Proportional-Integral-Resonant Current Control Strategy for a Wind-Driven Brushless Doubly Fed Generator during Network Unbalance

“…Nevertheless, as shown in Figure 1, due to the direct connection between the PW of BDFG and the network, BDFG is very susceptible to network disturbances such as network voltage unbalance. The negative sequence component of unbalanced network voltages will lead to the unbalance of PW currents, distortions of RW and CW currents, pulsations of PW power, and machine torque [25][26][27]. These adverse effects have deleterious effects on WDBDFG and even lead to damage to its electrical and mechanical parts.…”

“…Thus, it is very necessary to study the control methods for WDBDFG under network unbalance so as to improve the capability to resist the network unbalance. Thus far, the modeling and control for WDBDFG under network unbalance have been investigated in [25][26][27][28][29]. Nevertheless, the controls in [25,28,29] have similar drawbacks, including adopting a double-closed loop control structure, involving the decomposition of both CW and PW current sequence components, and the cross-coupling terms in control loops being totally or partially neglected.…”

“…In addition, since it was not CW current references but the PW current references under different control objectives were deduced, a double-closed loop design was needed. In order to address the problems mentioned above, improved controls were proposed in [26,27], where a single-loop proportional-integral (PI) controller for CW current was proposed to realize the control objectives set. Moreover, because feedforward control was also applied in the CW loop by using all the disturbances and couplings deduced, decoupled control was also improved.…”

“…Moreover, because feedforward control was also applied in the CW loop by using all the disturbances and couplings deduced, decoupled control was also improved. Nevertheless, in [26,27], a dual PI controller including a positive and a negative sequence CW current controller was designed, and the extraction of positive and negative sequences of CW currents was still necessary. However, because the extraction process can introduce significant amplitude and phase errors, the dynamic response of CW current is affected, and CW current cannot realize fully decoupled control during the transient process.…”

Suspension Strategy of Maglev Vertical Axis Wind Turbine Based on Sliding Mode Adaptive Neural Network Predictive Control

“…T HE wind power generation in low wind speed areas is increasingly on the agenda with the development of energy strategies, and low wind speed wind power is gradually attracting attention [1][2][3]. But unfortunately, low wind speed areas often have the disadvantage of frequent changes in wind speed and wind direction, so the application of vertical axis wind turbines (VAWT) has received extensive attention.…”