异质功率器件组合型多电平电路的拓扑演化方法与混频调制技术研究

The implementation of Wide-Bandgap (WBG) power devices can significantly improve the power density of the power electronic converter. However, the cost issue has slowed down the pace of WBG power devices entering the market. Nowadays, the applying of Multi-Material-Devices (MMD) based converter topologies can partially lower the cost. However, they still face several problems such as lacking the degree of freedom, high switching losses on their Si device part and unbalanced thermal stress. Therefore the power density is limited. In this application, researches will aim to develop MMD based multilevel converter topologies. Two main topics are covered. (1) Firstly, a series of MMD based multilevel converter topologies are proposed which enables low frequency switching on Si devices and high frequency switching on WBG devices. The basic structures of the topologies are derived. The derivation method for new topologies is investigated. It provides new converter solutions to realize high power density in the high power area. (2) Secondly, a new degree of freedom-Switching Frequency Ratio (SFR) is proposed. A Composited Frequency Modulation (CFM) technology is investigated with the utilization of SFR. It enables the balancing of thermal stress on each device for the MMD based multilevel converter system. The upper boundary of the power rating and the maximum power density can be derived by using the proposed CFM technology. It provides powerful tools for the modulation scheme design of high power converters. This project dedicates to delivery the next-generation topology and modulation method solution for the high power density high power converter, which will break through the limitation on both the cost and the power density of nowadays converter design. It provides a new research direction in the area of high power density power electronic converters, which will accelerate the development of converter technology for the green energy industry in China.

宽禁带器件的使用可大幅提高变流器功率密度，然而全宽禁带器件变流器的成本问题严重制约其产业化推广。现有硅基器件-宽禁带器件(异质器件)组合方法虽降低了变流器成本，但控制自由度不足、硅基器件开关损耗大、异质器件间温升不均，严重影响了系统性能。本项目以异质功率器件组合型多电平拓扑为载体，重点研究以下内容：（1）研究硅基器件低频动作、宽禁带器件高频运行的组合型多电平变换器结构及其拓扑演化方法，为大功率高密度变流器提供新方案；（2）提出异质器件开关频率比的概念，以此为新控制自由度，研究组合型多电平电路的混频调制技术，实现异质器件的热应力均衡，探索基于异质器件组合的多电平变流器功率容量与密度极限，为大功率高密度变流器调制提供科学依据。本项目力图设计新颖大功率高功率密度变流器拓扑与调制方案，突破现有设计在成本与功率密度上的局限，为高功率密度变流器研究提供新思路，促进我国绿色能源产业中变流器技术的发展。

在光伏发电、电动汽车、多电及全电飞机、高速中压电气传动等大功率高密度变流器应用场景中，宽禁带功率器件的使用可大幅提高变流器的变换效率与功率密度。然而全宽禁带器件的成本问题严重制约了其产业化推广。现有硅基器件-宽禁带器件(异质器件)组合应用方法虽降低了变流器成本，但控制自由度不足、硅基器件的开关损耗大、异质器件间的温升不均，严重影响了系统性能。.针对上述问题，本项目以异质功率器件组合型多电平拓扑为载体，重点针对异质功率器件组合型多电平电路的拓扑演化方法以及异质功率器件组合型多电平电路的混频调制技术两个关键科学问题开展研究工作。.本项目研究揭示了异质功率器件组合型多电平拓扑衍生规律，提出一系列高效率低成本组合型器件多电平拓扑，包括异质功率器件组合型三电平整流器拓扑，五电平整流器拓扑，以及具有电容均衡控制能力的四电平拓扑等。另一方面，项目通过挖掘异质功率器件组合型多电平拓扑的调制自由度，提出了适用于组合型拓扑的空间矢量调制策略以及通用多步软开关调制方案。项目设计了9.5kW/L，100kW的异质功率器件组合型三电平样机并进行了全面测试，实现了最高效率约为99.11%，满载效率为98.71%。.本项目研究全面完成项目的既定研究目标，研究成果丰硕。该项目已资助发表(含录用)SCI检索期刊论文7篇，EI检索国内期刊/国际会议论文7篇，其中电力电子学科国际权威期刊 (IEEE Trans. Power Electron.)SCI 论文5篇，授权发明专利3件，取得了良好的学术成果。经此项目培养，申请人入选浙江省“万人计划”青年拔尖人才项目，获中国机械工业联合会科技进步一等奖，中国电源协会科技进步特等奖，并获得浙江省自然科学基金重点基金项目资助。.本项目研究突破现有设计在成本与功率密度上的局限，为高功率密度变流器的研究提供新的思路。促进我国绿色能源产业中变流器技术的革新。同时，相关研究成果将形成具有自主知识产权的发明专利，提升国家在该领域的国际竞争力。