基于直流母线接入的大功率模块化储能双向DC/DC变换器及功率流控制研究

Energy storage technology is helpful to the stability of intermittent energy power generation and ensures the operation security of power system. Energy storage technology is one of the key to promote the large-scale application of wind and photovoltaic power generation. The research got the attention from the countries all over the world. With the requirement of MW level energy storage system as the goal, the high power distributed modularization energy storage system and power flow control based on DC bus access will be mainly researched in this project. The high voltage high power bidirectional DC/DC converter topology and power bidirectional transmission control method will be studied. And the research of operating mode and dynamic model for energy storage module in distributed energy storage is necessary. The SOC(state of charge) and intermittent energy state are used to control the operating mode of converter, so as to realize dynamic load power sharing among different energy storage modules. Combining with battery-ultracapacitor hybrid storage, the rapid response control strategy under non ideal conditions for the voltage flicker and mutation load will be researched. Meanwhile the hybrid storage can also improve the low voltage ride-through (LVRT) capability of wind power system. Through the research in this project, the key technology will be solved for the high power bidirectional DC/DC converter and system control in energy storage system, and the basic theory and the design methode of an engineering application can be also formed in high power dc energy storage equipment.

储能技术有助于间歇性能源发电的稳定性和可靠性，保证电力系统运行安全，是促进风力光伏发电规模化应用的关键技术之一，该方面的研究得到了世界各国的高度重视。本项目以MW级储能系统需求为目标，研究基于直流母线接入的大容量分布式模块化储能系统及关键技术。主要研究构建适合高压大功率的双向DC/DC变换器拓扑及功率双向传递控制方法；探索和研究分布式储能各个模块多种工作模式及其切换的动态模型，根据SOC及间歇能源发电状态控制变换器工作模式，实现各储能模块之间功率的合理分配；结合蓄电池和超级电容混合储能，研究大容量系统针对电压闪变、负载突变等非理想工作条件下所需要的快速响应控制策略，提高风电系统的低电压穿越能力。通过研究，解决储能系统大功率DC/DC变换器及系统控制的关键技术，形成较为系统性的分析理论和设计方法，为大功率直流储能装备的工程设计和应用奠定理论基础。

本项目主要研究大容量分布式模块化储能系统所涉及的适合大功率高电压的非隔离双向DC/DC变换器拓扑、使系统稳定运行的功率平衡控制策略、多储能模块并联协调运行并能实现储能模块之间功率合理分配等的关键技术。.开展了适合大容量储能的非隔离双向DC/DC变换器拓扑族研究，研究了6种拓扑，包括超高增益三电平双向DC/DC变换器、基于FIBC的超高电压级联双向DC/DC变换器、Buck-Boost集成半桥型CLLC双向DC/DC变换器等，其中4种已申请发明专利。开展了多储能模块分布式运行的负荷分配控制研究，提出了SOC幂指数函数改进下垂控制，可实现各储能模块负荷的合理分配和SOC均衡，且无需低带宽通讯。开展了以直流母线电压稳定为目标的功率流控制策略和充放电平滑切换研究，可根据直流微电网中新能源发电、电网能源、负载的功率状况自动平衡这些功率。提出了一种基于蓄电池和超级电容混合储能(HESS)的综合控制策略，并实现直流母线电压瞬态波动的快速有效抑制，提高系统的稳定性。开展了锂电池荷电状态估算研究，建立了双井模型同Thevenin电动势模型相结合的荷电状态(SOC)离散数学模型，并形成了一种基于该模型的在线非线性辨识的SOC估算方法。.在执行本项目开展中，共发表论文29篇，其中，SCI收录论文3篇，EI收录论文16篇；申请发明专利共计9项；培养博士研究生3名，硕士研究生9名。.通过本项目的开展解决了直流微电网中分布式储能系统的一些关键技术，对涉及分布式储能系统的设计、控制及理论进行了深入分析，形成了对工程实施有一定普遍指导意义的技术基础。