面向大功率微电网和微网群的多重化电流源变流器关键技术研究

In order to solve the power flow and power quality problems in high power microgrids and microgrid clusters, multi-modular current source converter and its corresponding control strategies are proposed in this project. The research includes topology, modulation, and control of current source converters, as well as the coordination of voltage source and current source converters in a microgrid system. To overcome the limitation of inaccurate harmonic current control of conventional low switching-frequency current source converter, the project proposes an improved Space Vector Modulation method for sharing DC link current and the decoupling method for selective line current harmonic control. To realize the simultaneous operation of voltage source and current source converters, the coordinated control of virtual synchronous generator and current source converter is proposed to achieve rapid power control in grid-tied mode, seamless transfer between grid-tied and islanding modes, power sharing in islanding operation, and the simultaneous mitigation of supply voltage and grid current harmonics. Finally, to satisfy the requirement of microgrid cluster interconnection, a hierarchical control algorithm is proposed to realize rapid power control and DC rail current ripple reduction in a back-to-back current source converter. The research work in the project can provide theoretical and experimental support for the application of current source converters in microgrid and microgrid cluster power conversion, optimization, and control.

针对大功率微电网功率控制和电能质量控制的问题和需求，本项目从电流源型微电网变流器拓扑、调制、控制、电流源和电压源变流器协调等方面展开深入的研究，提出了基于多重化电流源的微电网接口变流器解决方案。为了解决低开关频率电流源难以精确控制谐波电流和非线性负载污染电网电流的问题，提出了基于改进空间矢量调制的直流母线电流均流控制和基于解耦控制的指定谐波消除法；针对电流源变流器和电压源变流器在微网中共存的特性，开展基于虚拟同步机和电流源协调控制的并网快速功率调节、离网功率分配、无缝模式转换以及电网电流和供电电压谐波抑制的研究；根据大功率微电网群互联的要求，开发一种基于改进空间矢量调制的直流电流均流和共模电压抑制同步控制策略，并提出基于分层控制的背靠背电流源潮流控制和直流母线纹波抑制方法。本项目的研究可拓展电流源变流器的应用领域，为其在微电网与微电网群间的能量交互、优化、控制奠定理论和实验基础。

针对大功率微电网功率控制和电能质量控制的问题和需求，本项目从电流源型微电网变流器拓扑、调制、控制、电流源和电压源变流器协调等方面展开深入的研究，提出了基于多重化电流源的微电网接口变流器解决方案。针对电流源在低开关频率下难以精确控制谐波电流和非线性负载污染电网电流的问题，本项目提出了基于改进空间矢量调制的直流母线电流均流控制和基于解耦控制的特定谐波消除法；针对电流源变流器和电压源变流器在微网中共存的特性，本项目开展了基于虚拟同步机和电流源协调控制的并网快速功率调节、离网功率分配、无缝模式转换以及电网电流和供电电压谐波抑制的研究，提出了电流源型分布式电源和虚拟同步机协调控制的方法，充分利用虚拟同步机的下垂特性来实现了在孤岛模式下不同种类变流器之间的均分配；为了满足大功率微电网群互联的要求，本项目提出了一种基于改进空间矢量调制的直流电流均流和共模电压抑制同步控制策略，并提出基于分层控制的背靠背电流源潮流控制和直流母线纹波抑制方法。本项目的研究可拓展电流源变流器的应用领域，为其在微电网与微电网群间的能量交互、优化、控制奠定理论和实验基础。