矩阵变换器输入无功特性及控制研究

Demand for reactive power is very urgent in many applications of matrix converter, but it is not easy to satisfied, due to the complicated control and limited range of the input reactive power of matrix converter. Thus, this project is dedicated to investigate the reactive power characteristics and related issues of matrix converter. In the aspect of fundamental theory, the generation principle of the matrix converter reactive power is studied, involving the generation sources and energy interaction mechanism; the interrelations between the reactive power and topologies, modulation strategies, operating status, load properties would be revealed. To overcome the limited range of reactive power regulation, a constructive method based on space vector synthesis and a method based on finite set predictive control are presented, and in the topology layer, new matrix converter topology integrated with static synchronous compensator is designed. Further, the effect of these methods on the system efficiency and waveform quality is studied. In the aspect of practical application, the doubly-fed wind power system and unified power flow controller based on matrix converter are considered, and the related reactive power allocation mechanism are the key issues that should be discussed; by fully exploiting and utilizing the additional control degree of freedom in these specific loads, the optimum reactive power control would be achieved in these systems. The research achievements will be beneficial to extend the applied range and enhance the adaptability for matrix converter, and will be of important scientific significance for promoting the development and perfection of the theoretical system of matrix converter technology.

矩阵变换器的许多应用场合对无功有着迫切需求，但矩阵变换器输入无功控制复杂且范围受限，难以满足应用需求。为此，本项目拟对矩阵变换器输入无功特性及控制展开研究。基础理论方面，研究矩阵变换器输入无功产生机理，探究无功来源及相关能量交互机制，揭示输入无功与拓扑结构、调制策略和负载特性等因素之间的相互关系。为克服输入无功范围受限，在调制层面，提出空间矢量调制框架下的构造性扩大无功方法和基于有限集预测控制思想的扩大无功方法，在拓扑层面，提出集成静止同步补偿器功能的矩阵变换器新拓扑，并进一步研究这些方法对系统效率及波形质量的影响。实际应用方面，研究基于矩阵变换器的双馈风电系统、统一潮流控制器的无功优化分配机制，充分挖掘和利用此类负载额外存在的自由度，实现系统最优无功分配目标。研究成果将有助于拓展矩阵变换器的应用范围和在特定场合的适应性，对推动矩阵变换器技术理论体系发展与完善具有重要的科学意义。

矩阵变换器的许多应用场合对无功有着迫切需求，但矩阵变换器输入无功控制复杂且范围受限，难以满足应用需求。为此，本项目对矩阵变换器输入无功特性及控制展开了研究。首先，从调制策略层面，项目针对双级矩阵变换器提出一种基于空间矢量合成的构造性无功扩大调制方法，在确保负载正常工作的同时优化分配各空间矢量的占空比。针对单级矩阵变换器提出了一种基于有限集预测控制的无功扩大方案，直接将最大化输入无功范围当作控制目标，以此优先选择开关状态，解除了调制规则对输入无功控制的约束。通过与常规方法对比，这两种方法均可提升矩阵变换器对输入无功的控制能力。从拓扑结构层面，项目提出一种集成静止同步补偿器功能的矩阵变换器拓扑，即在双级矩阵变换器中间直流环节设计了切实可行的附属电路，使其整流级可独立地向电网提供动态无功补偿，而不受负载电流及运行状态的约束，这极大地改善了双级矩阵变换器的无功控制能力。从无功应用角度，项目分别对基于矩阵变换器的双馈风力发电系统以及统一潮流控制器系统提出了相应的无功优化控制方案。这些研究成果完善了矩阵变换器技术理论和方法，也为提升矩阵变换器在特定应用场合的适应性提供了理论支撑。