The increasing penetration of dc distributed energy resources (DERs) and dc loads has motivated the utilization of dc microgrids (MGs). In this paper, a new two-level control scheme is proposed for accurate power sharing and appropriate voltage regulation in dc MGs during islanded operation mode. In the primary control level, a $P-\dot {V}$ droop method is proposed to eliminate the dependency of power sharing among DERs on line resistances. Since the ${P}-\dot {V}$ droop deviates the voltage derivative to a nonzero value, a voltage derivative restoration mechanism is adopted in the secondary control level to provide voltage stability. The secondary control level also compensates the voltage deviations by cascading an outer voltage control loop with the inner voltage derivative restoration loop. The secondary control signal is broadcasted to each DER via a unidirectional low-bandwidth communication link. Small signal stability of the proposed scheme is analyzed by studying the locus of the system eigenvalues. To verify the efficacy of the proposed method and compare it with the conventional scheme, real-time simulations in OPAL-RT lab setup are provided.

中文翻译：

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一种基于的两层控制方案 磷 —— 伏 直流微电网中精确功率分配和电压调节的下垂特性

直流分布式能源 (DER) 和直流负载的日益普及推动了直流微电网 (MG) 的使用。在本文中，提出了一种新的两级控制方案，用于在孤岛运行模式下对直流 MG 进行准确的功率分配和适当的电压调节。在初级控制水平，一个 $P-\dot {V}$ 提出了下垂方法来消除 DER 之间功率共享对线路电阻的依赖性。由于 ${P}-\dot {V}$ 下垂使电压导数偏离到非零值，在次级控制级采用电压导数恢复机制来提供电压稳定性。次级控制级还通过将外部电压控制回路与内部电压导数恢复回路级联来补偿电压偏差。次级控制信号通过单向低带宽通信链路广播到每个分布式能源。通过研究系统特征值的轨迹，分析了所提出方案的小信号稳定性。为了验证所提出方法的有效性并将其与传统方案进行比较，提供了 OPAL-RT 实验室设置中的实时模拟。