An Improved Droop Control Method for DC Microgrids Based on Low Bandwidth Communication With DC Bus Voltage Restoration and Enhanced Current Sharing Accuracy
An Improved Droop Control Method for DC Microgrids Based on Low Bandwidth Communication With DC Bus Voltage Restoration and Enhanced Current Sharing Accuracy
复制标题
基于低带宽通信、直流母线电压恢复和增强均流精度的改进直流微电网下垂控制方法
DOI：
10.1109/tpel.2013.2266419
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发表时间：
2014-04-01
影响因子：
6.7
通讯作者：
Vasquez, Juan C.
中科院分区：
文献类型：
--
作者：
Lu, Xiaonan;Guerrero, Josep M.;Vasquez, Juan C.
下垂控制是直流微电网负载均流的基本控制方法。传统的直流下垂控制方法是通过随着输出电流的增加线性地降低直流输出电压来实现的。这种方法有两个局限性。首先，考虑到下垂控制直流微电网中的线路电阻，由于每个变换器的输出电压不可能完全相同，因此输出电流分配精度降低。第二，直流母线电压偏差由于下垂动作而随负载增大。为了提高直流微网的运行性能，提出了一种基于低带宽通信（LBC）的改进下垂控制方法。与传统方法相比，控制系统不需要集中式次级控制器。相反，它使用本地控制器和LBC网络在转换器单元之间交换信息。下垂控制器用于实现独立操作，并且在每个变换器中使用平均电压和电流控制器，以同时提高均流精度和恢复直流母线电压。所有的控制器都是本地实现的，LBC系统仅用于改变直流电压和电流的值。因此，一个分散的控制方案完成。基于MATLAB/Simulink的仿真测试和基于2 × 2.2 kW样机的实验验证，以证明所提出的方法。
Droop control is the basic control method for load current sharing in dc microgrid applications. The conventional dc droop control method is realized by linearly reducing the dc output voltage as the output current increases. This method has two limitations. First, with the consideration of line resistance in a droop controlled dc microgrid, since the output voltage of each converter cannot be exactly the same, the output current sharing accuracy is degraded. Second, the dc-bus voltage deviation increases with the load due to the droop action. In this paper, in order to improve the performance of the dc microgrid operation, a low-bandwidth communication (LBC)-based improved droop control method is proposed. In contrast with the conventional approach, the control system does not require a centralized secondary controller. Instead, it uses local controllers and the LBC network to exchange information between converter units. The droop controller is employed to achieve independent operation, and the average voltage and current controllers are used in each converter to simultaneously enhance the current sharing accuracy and restore the dc bus voltage. All of the controllers are realized locally, and the LBC system is only used for changing the values of the dc voltage and current. Hence, a decentralized control scheme is accomplished. The simulation test based on MATLAB/Simulink and the experimental validation based on a 2 x 2.2 kW prototype were implemented to demonstrate the proposed approach.