并网型直流微电网协调控制策略

The Coordinated Control Strategy for Grid-Connected DC Microgrid

大量的电力电子装置接入直流微电网中,降低了系统的惯性,因此需要设计微网内功率的控制策略,以保证母线电压不发生严重波动甚至崩溃。提出了一种基于光伏、储能、联网单元的并网式直流微电网协调控制策略。以母线的简化电路为基础,分析了直流母线电压与功率平衡的关系;划分系统的4种工作模式和运行状态,据此对母线电压进行分层,并设计了基于对等控制策略的联网变流器、储能单元和光伏控制方案。仿真结果表明,该控制策略能够在微电网内出现功率不平衡时,将母线电压波动控制在额定电压的±10%以内,且下垂控制使相关设备具有即插即用的功能,实现了设备层和系统层在无通信条件下的协调配合。

As large quantity of power electronic devices are connected to the DC microgrid,which reduces the inertia of the system,it is necessary to design a power control strategy in the microgrid to ensure that the bus voltage does not fluctuate seriously or even collapse. In this paper,a coordinated control strategy for the grid connected DC microgrid based on photovoltaic,energy storage and networking units is proposed. First,the relationship between DC bus voltage and power balance is analyzed based on the simplified bus circuit. Second,the system operation is divided into four working modes and operation states,based on which the bus voltage is layered,and the control strategy for the interconnection converter,energy storage unit and photovoltaic is designed based on the peer-to-peer control strategy. The simulation results show that the proposed control strategy can control the bus voltage fluctuation within ± 10% of the rated voltage in case of power imbalance in the microgrid,and the droop control enables the relevant equipment to have the plug-and-play function,so as to realize the coordination between the device layer and the system layer without communication.