含新型"源""荷"交直流配电系统中智能通用变压器有源前端变换技术与协调控制策略研究

配电网绿色化变革面临重大挑战：(1)保证高品质供电；(2)有效接纳分布式新能源；(3)支撑电动汽车广泛接入；(4)保证局部供电的安全性、独立性、可控性。基于传统工频电力变压器的配电方式已无法满足上述挑战，可从"智能通用变压器"角度来建立含有新型"源""荷"交直流配电系统来满足智能配电网发展的需求，其中有源前端控制器(AFEC)作为智能通用变压器的关键技术，可方便地为新型"源"及"荷"提供直流接口；用户端DC-AC逆变器可保证高品质供电。本项目首先对智能通用变压器中AFEC技术展开研究，提出将双降压/升压全桥式变换器与CLLC谐振变换器模块作为AFEC拓扑结构的核心组成部分，采取SiC技术来探讨高频化对AFEC影响，同时提出基于单级控制系统结构概念来研究AFEC统一控制策略；最后研究智能通用变压器在交直流配电系统中功率协调控制策略及故障保护策略，来提高配电网局部供电的可控性、灵活性、独立性。

Green development of distribution grid will face big challenges:(1)to ensure high quality of power supply; (2)to absorb distributed renewable energy effectively;(3)to support wide electric vehicles' plug-in;(4)to ensure the security, independence and controllability of local distribution grid.The power supply system based on the traditional power transformers has been unable to meet the above challenges, thus from the point of "Intelligent Universal Transformer, IUT", a novel AC and DC power distribution system having new "Source" and "Load" is construted to meet the demand for smart distribution grid development where active front-end controller (AFEC) as a key technology of IUT can provide DC interface for new "Source" and "Load" easily and customer DC-AC inverter can ensure high-quality power supply. First this project will focus on the AFEC technology of IUT, the key part of AFEC system structure based on dual-boost/buck full-bridge converter with CLLC resonant converter module is proposed where SiC devices are used to investigate the high frequency effect to AFEC system. Additionally AFEC unified control strategy based on the proposed single-stage controll system structure concept is studied. In the end, to improve the controllability, flexibility and independence of the local power supply system, the power coordinated control and fault protection strategies of IUT are studied in the AC and DC power distribution system with new "Source" and "Load".