高频隔离型模块化多电平级联变换器及其在新能源中压交直流并网中应用基础研究

基于模块化多电平级联变换器与中高频隔离技术的新能源中压并网发电系统能够解决传统升压工频变压器质量重与体积大带来的安装维护成本高问题， 受到世界各国学者广泛关注，具有广阔的应用前景。本项目以新能源中压交直流混合并网发电系统为研究对象，突破现有中高频隔离型系统的体系结构，借鉴传统模块化多电平级联变换器拓扑特点和形成规律，结合高频链概念，提出单级式隔离型模块化多电平变换器(I-M2C2)拓扑构造理论，然后探讨分析I-M2C2高效调制原理及其多目标优化设计方法，研究I-M2C2各端口能量特性及其中压交直流并网控制与保护策略，探索基于I-M2C2的光伏、风力中压交直流并网典型汇集系统结构及其协调控制策略，最后搭建I-M2C2型新能源中压交直流混合发电系统实验平台对所提出的拓扑结构及控制策略进行验证，本项目的研究将为新能源柔性中压交直流并网运行提供新的解决思路和解决方案。

For medium-voltage grid integration, renewable energy systems (RESs) based on modular multilevel cascade converters (MMCC) and medium/high-frequency technology can solve the problems of high capital and installation costs induced by the heavy weight and large size of traditional step-up line-frequency transformer, which have achieved extensive attention and a broad application. This project focuses on medium-voltage AC and DC grid integration system of RESs, to break through the existing medium/high-frequency isolated system architecture, single-stage I-M2C2 topology theory is proposed combining MMCC’s topology characteristics and formation rulethanks wih thigh-frequency link concept. High-efficiency modulation and multi-objective optimization design method are analyzed and given. Medium-voltage AC and DC grid control and protection scheme is proposed based on multi-ports’ energy characteristics. Then the typical collection system structure of medium-voltage AC and DC grid integration of PV and wind based on I-M2C2 is explored. Finally, a verification platform for the I-M2C2 RES is established to prove the proposed topology and control scheme. This project will provide new solutions for the flexible medium-voltage AC and DC grid integration of RESs.