智能电网潮流多解性对接口变换器的影响及研究

One of the main targets of smart grid is to connect a large number of renewable energy power generation systems or energy storage systems to the power grid reliably, which will make the power flow vary with time and have multiple solutions, and then affect the operation of grid-interfacing converters seriously. It is shown that the failure rate of grid-interfacing converters increases over 3 times by the statistics results. Therefore, the research on the effect of multiple power flow on grid-interfacing converter is a very significative topic in present. This project will study on the effect of multiple power flow on grid-interfacing converters, as well as the effect of the nonlinear characteristics of grid-interfacing converters on time-varying power flow at first; and then the control strategies and parameter design methods for the grid-interfacing converters are proposed, which can satisfy with the bi-direction constraint of time-varying power flow and renewable energy flow. The innovations of the project can be concluded as following: .(1) Different from the study of independent operating converter, this project considers the grid-interfacing converter, power grid and renewable energy as an entirety by the time-varying multiple power flow, which reveals the operation conditions of grid-interfacing converter truly. .(2) The proposed concept of bi-direction dynamic constraint converter, enriches the study scope of the converter. The proposed control strategy and parameter design method could improve the stability of the grid-interfacing converter.

智能电网的主要目标之一是实现大规模可再生能源发电系统和储能系统可靠地接入电网，电网潮流呈现出时变和多解的特点，对接口变换器的运行产生了极大的影响，据国外统计，接口变换器的故障率增加了3倍以上。为此，开展智能电网潮流多解性对接口变换器影响的研究成为目前一个十分有意义的课题。本项目拟研究电网时变潮流对接口变换器的影响，同时研究接口变换器非线性特性对电网潮流时变性造成的影响，从而提出满足电网时变潮流和可再生能源时变潮流双向动态约束要求的接口变换器控制策略和参数设计方法，保证接口变换器安全工作。项目的创新之处在于：一是与现有独立运行变换器的研究不同，通过时变、多解潮流将接口变换器与电网、可再生能源结合为一个整体进行研究和分析，真实地反映了接口变换器的运行状况；二是提出了一个双向动态约束变换器的概念，丰富了变换器的研究范围，所提出的控制策略和参数设计方法可以进一步提高接口变换器的运行稳定性。

接口变换器不仅是连接智能电网与负载之间的必需环节，而且是实现可再生能源发电系统并网的关键部件，因此，开展电网时变潮流和可再生能源时变潮流对接口变换器的影响具有十分重要的意义。本项目在掌握可再生能源并网带来电网潮流变化规律以及接口变换器对电网的谐波冲击影响的基础上，以三相电压型PWM整流器和光伏并网逆变器为例，分别研究了单一型接口变换器和级联型接口变换器的非线性动力学行为，通过建立变换器的整体数学模型，得到不同类型接口变换器稳定运行工作条件；根据电力电子变换器的能控性理论，提出了适用于接口变换器的最少模态控制法、改进小波调制法和电能质量控制策略，进一步提高了接口变换器的输出性能；针对接口变换器输入电压范围宽、输出负载变化范围大的实际需求，利用本项目提出的一般性变换器拓扑设计方法，发明了高性能阻抗源逆变器、无桥高增益PFC变换器、单开关高增益变换器等一系列接口变换器。因此，本项目的研究成果对保证接口变换器的稳定运行、推动接口变换器的理论研究、促进智能电网的发展和可再生能源的应用具有重要的科学和实际意义。.本项目已发表SCI收录论文6篇、EI收录论文18篇、核心期刊论文2篇，授权发明专利13项，培养硕士5名，协助指导博士2名，出站博士后2名，超过了项目的预定成果目标。