复合级联多电平电池储能功率转换系统研究

The project carry out research on the battery energy storage power conversion system (PCS) based renewable energy power fluctuation smoothing. A compound cascade H-bridge (CCH) battery energy storage power conversion system (CCH-PCS) is proposed by the applicant. In CCH-PCS, bi-directional isolated DC/DC converter is inserted between the traditional cascade multilevel PCS H-bridge dc side and energy storage battery. The CCH-PCS is designed with modular and high redundancy. The energy storage PCS which is used for smoothing fluctuation power is always working in the conditions of power fluctuations. When bi-directional isolated DC/DC converter is controlled appropriate, the rate of change of energy storage battery charge and discharge current can be smoothed and safe and efficient operation of the storage battery can be promoted.The applicant plans to research energy storage battery and PCS matching theory and control design method based renewable energy power fluctuation, PCS topology and loss optimization design method, PCS multi-module interconnect stability analysis and networked control method, PCS grid side power control and battery SOC ballance management method, PCS redundancy protection method. Developed 200kW/690V AC 9 modules CCH-PCS experimental platform to verify the theory and method proposed in this project.

本项目开展基于可再生能源功率波动平滑的电池储能功率转换系统(Power Conversion System-PCS）研究，申请者提出一种复合级联多电平电池储能PCS，它在传统的 级联H 桥PCS 的H 桥直流侧和储能电池之间插入隔离型双向直流变换器，具有模块化设计和高冗余性。复合级联储能PCS 工作在功率大波动条件下，通过合理控制双向直流变换器，减缓储能电池充放电电流变化率，促进储能电池的安全高效运行。申请者计划研究功率大波动下储能电池与PCS 匹配理论与控制设计方法、PCS 主电路拓扑设计与损耗优化方法、PCS 中多模块互联稳定性分析和网络化控制方法、PCS功率控制策略和电池荷电状态均衡控制方法、PCS 冗余保护方法。研制200kW/690V接入、9模块复合级联H桥电池储能PCS，验证提出的理论和方法。

本项目面向用于可再生能源功率波动平滑的电池储能领域，提出了一种适合中压电网直接接入的复合级联多电平电池储能功率转换系统的电路拓扑。该拓扑在传统的级联H桥储能变换器的H桥直流侧和储能电池之间插入了隔离型双向直流变换器，具有模块化设计和高冗余性。复合级联储能变换器工作在功率大波动条件下，通过合理控制双向直流变换器，可以减缓储能电池充放电电流变化率，促进储能电池的安全高效运行。.项目负责人和参与者研究了变换器效率优化方法，通过比对各种软开关技术最终确定采用软开关双向直流变换器作为电池模块与变换器H桥模块的接口；研究了储能变换器共模电流抑制方法，通过分析储能功率转换系统漏电流模型并提出相应滤波方法，抑制了级联式电池储能系统的共模干扰；研究了储能变换器中多模块互联稳定性分析和网络化控制方法、储能变换器电池能量管理方法、储能变换器故障诊断与冗余保护方法、储能变换器全工况无缝切换和电网故障穿越方法，通过多级荷电状态均衡控制策略和功率转换系统子模块和系统故障保护策略的应用，实现了电池系统的安全运行。通过分析储能功率转换系统阻抗模型，解决了弱电网运行稳定性问题。研制了3相共60链节的实验样机，全面验证了提出的理论和方法。