This article investigates the modeling and control of brushless doubly fed induction generator (BDFIG) under an unbalanced network. The system behavior of BDFIG under the unbalanced grid voltage is analyzed. The control strategies and different control targets of BDFIG in balanced and unbalanced networks are discussed. In order to achieve control targets, a current control strategy consisting of a primary controller and a secondary controller for the control winding is proposed. The primary controller is implemented in the positive-sequence synchronous rotating frame (SRF) to ensure the dynamic response of the system without sequence components separation, whereas the secondary controller is implemented in the negative-sequence SRF to control the negative-sequence current component only. A feedforward compensation for the negative-sequence current control is used to mitigate the sequence components separation influence on the dynamic response of the secondary controller. Experimental results demonstrate the effectiveness of the control strategy in suppressing the power and current oscillation of a BDFIG system under the unbalanced network.

中文翻译：

---

不平衡网络下无刷双馈感应发电机的双同步旋转框架电流控制

本文研究了不平衡网络下无刷双馈感应发电机（BDFIG）的建模和控制。分析了不平衡电网电压下BDFIG的系统行为。讨论了平衡和不平衡网络中BDFIG的控制策略和不同的控制目标。为了达到控制目标，提出了一种由控制绕组的初级控制器和次级控制器组成的电流控制策略。主控制器在正序同步旋转框架（SRF）中实现，以确保系统的动态响应而无序列分量分离，而次级控制器在负序SRF中实现，仅控制负序电流分量。用于负序电流控制的前馈补偿用于减轻序列分量分离对次级控制器的动态响应的影响。实验结果证明了该控制策略在不平衡网络下抑制BDFIG系统的功率和电流振荡的有效性。