开关电容型电子电力变压器的模块化集成优化与柔性控制方法

Electronic Power transformer has the significant effects on voltage conversion, power transmission and power quality control in the distribution network system. Against its problems of huge resource requirement such as copper and iron, deficiency in efficient and difficulty in integration, the research on modular integration optimization of Switched-Capacitor-Based electronic power transformer and its flexible control method will be developed. First, the circuit topology for low voltage distribution network access is constructed and the general rule of topological derivative is attained, and the evaluation index of topological properties is determined. Second, multi-frequency -scale modeling method of the proposed converter with the characteristic of multi-element, multi-value, multi-operation-mode is discussed. On this basis, a comprehensive strategy based on phase modulation is put forward to reduce circulation and current stress, and the safe commutation and soft switching operation are realized, combing with the close loop control to achieve regulation on bidirectional energy flow. Then, through the deep research on dual multi-target optimization strategy, the parameters optimization design under high power density and high full-load efficiency is solved. At last, the three-phase cascaded system will be decoupled into three independent single-phase by optimal separation of zero-sequence component from current reference, which would help to increase the control flexibility of each phase, and the influence to the control target will be reduced. Finally, the synergistic effect-increasing of various performances is obtained for Switched-Capacitor-Based electronic power transformer, which provides theoretical basis for its application in low voltage distribution network system.

电子电力变压器对配电系统的电压变换、能量传输和电能质量治理具有重要意义。针对其存在效率不高、难以集成化和对铜铁资源严重依赖等主要问题，本课题拟开展开关电容型电子电力变压器的模块化集成优化与柔性控制方法研究。首先构建适应低压配电网接入的电路拓扑并获得拓扑衍生的一般规律，确定综合表征拓扑性能的评价指标；其次，探讨该类具有多元、多值、多模态运行特征变流器的多频率尺度建模方法；在此基础上，提出基于移相的综合调制策略以减少功率回流和电流应力，并实现安全换流和软开关操作，结合闭环控制完成对能量流动的双向调控；再次，深入开展双重多目标优化策略研究，解决在高功率密度、全负载高效运行下的参数优化设计；最后结合最优指令分离的方法，将三相星形接入系统解耦为三相独立单相系统以增加控制自由度，并尽可能减少对系统控制目标影响。最终实现开关电容型电子电力变压器的各种性能协同增效，为其在低压配电系统应用提供理论基础。

本项目的研究目标是充分利用拓扑构造规律、建模方法、调控策略、参数优化及控制理论实现SCEPT 装置在中大功率等级下的灵活调控与高性能运行。重点研究内容包括：① SCEPT拓扑优化构建； ② SCEPT多尺度的建模； ③ SCEPT综合调控策略；④ 参数优化设计分析；⑤ 三相星型接的分相控制；. 本项目首先构建适应低压配电网接入的电路拓扑并获得拓扑衍生的一般规律，确定综合表征拓扑性能的评价指标；同时，探讨该类具有多元、多值、多模态运行特征变流器的多频率尺度建模方法；在此基础上，提出基于移相的综合调制策略以减少功率回流和电流应力，并实现安全换流和软开关操作，结合闭环控制完成对能量流动的双向调控；其次，深入开展双重多目标优化策略研究，解决在高功率密度、全负载高效运行下的参数优化设计；最后结合最优指令分离的方法，将三相星形接入系统解耦为三相独立单相系统以增加控制自由度，并尽可能减少对系统控制目标影响。很好地完成了项目的既定目标。.在国家自然科学基金项目的支持下，本项目组成员经过四年来的持续努力和深入研究，已按计划完成了全部研究内容，实现了项目申请时拟定的预期目标。申请人在本自然科学基金项目资助下，以第一/通讯作者发表（含在线发表）SCI检索IEEE期刊论文（中科院一区13篇，二区5篇），EI检索国际期刊/国际会议论文6篇，申请人以第一发明人身份授权国家发明专利21项，实用新型专利3项，取得了良好的学术成果。经此项目的培养，申请人入选福建省杰出青年基金资助（批准号：2018J06016）和厦门大学南强青年拔尖人才计划。