基于不对称状态估计和功率控制的分布式混合储能系统研究

随着客户侧储能系统的快速发展，充分利用分布式储能资源响应电力系统紧急功率输送、调频调峰等需求，成为避免储能系统重复投资、提高利用率的重要思路。本项目针对配置、工况有差异的混合储能系统分布式运行中出现的“不对称”状态估计及控制难题开展研究：1、提出一维电压前馈空间矢量调制和双频混合PWM调制两种新型链式PCS控制方法，实现PCS链节功率不对称控制；2、建立体现储能元件与电力电子电路耦合关系的广义等效模型及等效SOC指标，实现荷电状态不对称的混合储能单元状态实时估计；3、提出含动态下垂控制和ESOC一致性控制的混合储能系统分层分布式控制架构，实现全局功率控制目标在运行模式不对称的子系统之间最优化分配。通过上述研究，有效地将底层储能元件状态、上层电力电子接口与系统控制融合，优化混合储能系统的效率、可靠性和运行范围，为客户侧分布式储能资源高效参与电力系统运行控制提供电力电子理论基础与技术储备。

With the rapid development of customer-side energy storage system, fully utilizing distributed energy storage resources to meet the needs of power system, such as emergent power delivery and FM peak regulation, has become an important idea to reduce duplicated investment of energy storage system and enhance its utilization. This project focuses on the asymmetrical state assessment and control issues of hybrid energy storage system in distributed operation. 1. Two novel PWM control methods: one dimension voltage-feedforward space vector modulation and double frequency hybrid PWM modulation are proposed to realize asymmetrical power control of cascaded sub-modules in PCS. 2. The generalized equivalent model and the equivalent SOC algorithm are built to assess the real-time state of hybrid energy storage units which have asymmetrical states. 3. A hierarchical distributed control architecture, which consists of a dynamic droop control module and an ESOC consistency control module, is proposed to realize optimal power distribution between sub-systems with asymmetrical operation statuses in distributed hybrid energy storage system. Through the above researches, the fundamental characteristics of the energy storage components, the power electronics interface and the control system are combined effectively to improve the efficiency, reliability and operation range of the distributed control system significantly. This provides the valuable power electronics theory and engineering experience for the customer-side energy storage resources to participate in power system operation and control.