基于荷电状态的直流微电网中多储能分级运行控制方法

Hierarchical Operation Control of Multi-energy Storage in DC Microgrid Based on State of Charge

无通信前提下,直流微电网中储能单元常用的控制策略难以实现储能荷电状态(state of charge,SOC)均衡、最大化新能源利用率和母线电压支撑三方面的平衡控制,提出一种基于荷电状态的直流微电网中多储能单元分级运行控制方法。首先,考虑微电网多运行状态下对储能单元的不同需求,将储能单元状态划分为5种工作模式,且各模式的电压区间是根据SOC动态调节的。利用直流母线电压信号作为工作模式判据,各储能单元根据SOC大小投入充放电,实现分级运行。随后,功率调节控制根据储能单元各模式的电压区间自动调整下垂曲线,使投入运行的储能单元间根据SOC合理分配功率。最后,搭建了Matlab/Simulink仿真模型,仿真结果表明所提控制策略在无通信条件下可实现各储能单元SOC均衡,并且能够实现与其他源储单元协调运行,以最大化新能源利用率,避免了工作模式切换过程中母线电压大幅波动,证明了所提控制策略的可行性和有效性。

The necessary balanced control of the energy storage state of charge(SOC), the efficient use of energy and the bus voltage support for the energy storage units in DC microgrids can be hardly realized without complicated communication. In this paper, a hierarchical operation control strategy based on the state of charge is proposed for the distributed energy storage units in DC microgrid. First, considering the different needs of the energy storage unit in the multi-operation state of the microgrid, the operation of the energy storage unit is divided into five working modes according to the DC bus voltage signals. Second, with the SOC of the energy storage unit introduced into the voltage interval control, each voltage interval is dynamically adjusted with the SOC in order to achieve the hierarchical operation. Then, the power distribution control adjusts the droop curve automatically according to the voltage interval of each working mode of the energy storage unit so that the power of each energy storage unit is distributed with the respective SOCs. Finally, the results of Matlab/Simulink prove that the proposed control strategy can achieve SOC balance and efficient use of energy without communication. The deviation of the common DC bus voltage offset is within a reasonable range during the switching of working mode. The feasibility and effectiveness of the proposed control strategy are verified.