基于多电池储能系统的微网离网控制技术研究

发布时间：2018-08-09 19:04

【摘要】：储能系统是微网的重要组成部分,可以在微网中用于削峰填谷、改善电能质量、提高新能源供电稳定性和备用电源等,特别是在上级供电网络发生故障,微网在孤岛运行状态时,储能系统可以为微网中的负载供电。储能系统的并/离网控制策略,是实现这些功能的关键,并且随着微网负荷增大,需要进一步研究多台储能系统并联运行的控制方式。本文围绕储能系统离网无互联通信线情况下,多机并联运行控制展开研究,以保证孤岛稳定运行。针对储能系统多机并联合理功率分配机理,提出了基于下垂控制实现功率成比例分配的方法,深入研究了闭环参数对下垂控制策略的影响,提出了合理选取下垂系数和引线阻抗的方法,通过仿真验证了所提出的方法能够实现储能系统多机并联时,按要求合理分配功率。针对线路阻抗差异,通过引入虚拟阻抗补偿,实现储能系统多机并联时的均流控制,同时提出了二次调频方法,在储能系统离网运行出现频率越限时,通过二次调频使其恢复到允许范围内。针对下垂控制的缺陷,设计了储能系统虚拟同步机控制,深入研究了虚拟同步机控制参数对控制的影响,同时进行了基于虚拟同步机控制的小干扰稳定性分析,验证了虚拟同步机控制策略的稳定性以及控制参数对系统稳定性影响的趋势。针对虚拟同步机多机并联时的均流响应问题,提出了自整定惯量参数控制方法,仿真验证了控制算法的可行性。最后基于硬件在环实验平台进行了储能系统离网控制实验。通过硬件在环实验验证了储能系统换流器硬件控制系统的可行性,进一步验证了本文提出的控制方法的有效性。
[Abstract]:Energy storage system is an important part of microgrid. It can be used in microgrid to cut peak and fill valley, to improve power quality, to improve stability of new energy supply, and to improve reserve power supply, especially when power supply network at higher level breaks down. When the microgrid is running on an island, the energy storage system can supply power to the load in the microgrid. The parallel / off-grid control strategy of the energy storage system is the key to realize these functions, and with the increase of the micro-grid load, it is necessary to further study the control mode of parallel operation of several energy storage systems. In order to ensure the stable operation of isolated islands, this paper focuses on the parallel operation control of multi-computers without interconnected communication lines in the off-grid of energy storage system. In view of the reasonable power allocation mechanism of multi-machine parallel connection in energy storage system, a method of proportional power allocation based on droop control is proposed, and the influence of closed-loop parameters on droop control strategy is deeply studied. A reasonable method of selecting sag coefficient and lead impedance is put forward. The simulation results show that the proposed method can distribute power according to the requirement when the energy storage system is connected in parallel. In view of the line impedance difference, by introducing virtual impedance compensation, the current sharing control of energy storage system with parallel operation is realized. At the same time, a secondary frequency modulation method is proposed, when the frequency of off-grid operation of energy storage system exceeds the limit. It is restored to the allowable range by the second frequency modulation. Aiming at the defects of droop control, the virtual synchronous machine control of energy storage system is designed, and the influence of control parameters of virtual synchronous machine on the control is deeply studied. At the same time, the stability analysis of small disturbance based on virtual synchronous machine control is carried out. The stability of the control strategy of the virtual synchronous machine and the influence of control parameters on the stability of the system are verified. A self-tuning inertia parameter control method is proposed to solve the problem of parallel current sharing of virtual synchronous machines. The feasibility of the control algorithm is verified by simulation. Finally, the off-grid control experiment of energy storage system is carried out based on the hardware in loop experiment platform. The feasibility of the hardware control system of the converter of the energy storage system is verified by the hardware-in-loop experiment, and the effectiveness of the proposed control method is further verified.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM727

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