Droop coefficient correction control for power sharing and voltage restoration in hierarchical controlled DC microgrids
Droop coefficient correction control for power sharing and voltage restoration in hierarchical controlled DC microgrids
复制标题
DOI：
10.1016/j.ijepes.2021.107277
复制
发表时间：
2021-12
影响因子：
5.2
通讯作者：
Yang Han;N. Xing;Li Luqiao;Ping Yang;F. Blaabjerg
中科院分区：
文献类型：
--
作者：
Yang Han;N. Xing;Li Luqiao;Ping Yang;F. Blaabjerg
随着直流微电网的广泛应用，通过将附近的直流微电网互联，提高了可再生能源的利用率。由于MG通过不同的线路阻抗连接，因此在传统下垂控制方案中，在电流共享和电压调节的冲突目标之间存在直观的折衷。提出了一种具有动态下垂系数校正控制（DCCC）的分级控制结构，以实现直流发电机更好的功率分配。在所提出的分层控制方案中，下垂系数校正方法在初级，自动校正下垂系数和比例电流已被共享。此外，每个变换器的下垂系数也被动态调整，以处理不确定的线路阻抗的影响。性能的鲁棒性系统的不确定性也被证明。同时，通过三级控制水平，可以提供不同的电流比的微电网的直流母线，这实现了任意的微电网之间的功率共享。此外，小信号模型的开发，以研究在电压环，电压恢复控制器和下垂系数的控制参数的耦合关系的影响。最后，实验结果评估下垂系数校正控制方法和分层控制方案的直流MG电阻性和恒功率负载（CPL）条件下的有效性。
With the widely application of the DC microgrid (MG), the utilization of renewable resources is improved by interconnecting nearby DC MGs. Since MGs are connected by different line impedances, the intuitive tradeoff exists between the conflicting goals of current sharing and voltage regulation in the conventional droop control scheme. A hierarchical control structure with a dynamic droop coefficient correction control (DCCC) is presented to achieve better power sharing in DC MGs. In the proposed hierarchical control scheme, the droop coefficient correction method is employed in the primary level, which corrects the droop coefficient automatically and the proportional current has been shared. Moreover, the droop coefficient of each converter is also dynamically adjusted to deal with the impact of uncertain line impedances. The robustness of performance to system uncertainties is also demonstrated. Meanwhile, the different current ratio of the microgrids can be provided to the DC bus by using the tertiary control level, which achieves an arbitrary power sharing among the microgrids. In addition, a small-signal model is developed to investigate the effects of coupling relationship in the control parameters in the voltage loop, voltage restoration controller and droop coefficients. Finally, the experimental results are presented to evaluate the effectiveness of droop coefficient correction control approach and hierarchical control scheme for the DC MG under resistive and constant power load (CPL) conditions.