This article proposes an unbalanced voltage compensation method for a dispersed wind farm (DWF) by cooperating permanent magnetic synchronous generators (PMSGs) with a star-connected cascaded H-bridges (CHB) static synchronous compensator (STATCOM). The topology of a typical DWF is given and the mathematical models of CHB-STATCOM and PMSG inverter are established to show that the unbalanced grid voltage can be suppressed by controlling their virtual negative-sequence output admittance (NSOA). The relationship between maximum phase voltage and dc voltage corresponding to zero-sequence voltage injection is obtained to quantitatively analyze the negative-sequence current injection ability of the CHB-STATCOM. Moreover, the phase current limit is introduced to address the over-current problem, and a virtual NSOA method for sharing unbalanced voltage is proposed. An allocation coefficient calculation method is also proposed in consideration of both remaining capacity and voltage unbalanced factor (VUF) for different PMSGs. Furthermore, a coordinated control strategy of PMSGs and CHB-STATCOM for unbalanced voltage suppression is proposed. The effectiveness of the proposed coordinated control strategy is verified by simulation on a 50 MW DWF with a ±5 MVar star-connected CHB-STATCOM.

中文翻译：

---

分散风电场中PMSG和级联H桥STATCOM的协调控制策略以抑制不平衡电网电压

通过将永磁同步发电机（PMSG）与星形连接的级联H桥（CHB）静态同步补偿器（STATCOM）协作，提出了一种用于分散风电场（DWF）的不平衡电压补偿方法。给出了典型DWF的拓扑结构，并建立了CHB-STATCOM和PMSG逆变器的数学模型，表明可以通过控制其虚拟负序输出导纳（NSOA）来抑制不平衡电网电压。通过求出最大相电压与零序电压注入对应的直流电压之间的关系，定量分析了CHB-STATCOM的负序电流注入能力。此外，引入相电流限制来解决过电流问题，提出了一种虚拟的NSOA共享不平衡电压的方法。还提出了一种考虑不同PMSG的剩余容量和电压不平衡因子（VUF）的分配系数计算方法。此外，提出了一种用于不平衡电压抑制的PMSGs和CHB-STATCOM的协调控制策略。通过在具有±5 MVar星型CHB-STATCOM的50 MW DWF上进行仿真，验证了所提出的协调控制策略的有效性。