一种微源逆变器串联的微电网系统关键问题研究

项目名称： 一种微源逆变器串联的微电网系统关键问题研究

项目编号： No.51467010

项目类型： 地区科学基金项目

立项/批准年度： 2015

项目学科： 电工技术

项目作者： 王兴贵

作者单位： 兰州理工大学

项目金额： 52万元

中文摘要： 针对目前微电网广泛采用的交流、直流和混合结构中，普遍存在的环流、输出电压谐波含量大及系统控制复杂等问题，研究一种微源逆变器串联的微电网。在该微网结构中将多个微源逆变器的输出相串联，对所有逆变器采取载波变幅移相调制，使系统的输出电压为多电平波形。彻底解决了环流问题；减少了谐波含量；降低了微源逆变器的工作电压，减小电压应力和设备成本；系统控制的多样性和复杂性也得以简化；提高了电能质量。主要研究非对称串联结构、功率平衡与能量协调、微源逆变器独立控制、电压稳定性、微源解列与投入、系统小信号建模等内容。主要解决直流电压不变条件的满足、过调制、直流电压波动、系统降维与离散模型建立、死区效应影响等关键问题。目标是研究出一种高性能的新型微电网系统。项目提出了一种新型串联微网结构，以及一些对微源逆变器、功率优化平衡、串联微网电压稳定等控制的新方法和策略，为微网的组网方式提供了一种新的途径。

中文关键词： 微电网；逆变器串联；功率控制；谐波；稳定性

英文摘要： AC, DC and AC/DC hybrid structure are widely employed in a microgrid at present. Aiming at the problems such as the prevalence of circulating current, high harmonic content of output voltage and control complexity in the structure, a kind of microgrid with micro-source inverters connected in series is proposed. In the microgrid, the outputs of micro-source inverters are connected in series, the mixed modulation of variation amplitude carrier phase shift is applied for all inverters to make the output voltage to be multilevel waveform. This special structure can eliminate the circulation thoroughly, minimize harmonic content, decrease the operating voltage of the micro-source inverter, reduce voltage stress and the cost of equipment, simplify the diversity and complexity of system control and improve power quality. Asymmetric series structure, control of power balance and energy coordination, independent control of micro-source inverter, voltage stability, exit or joint of the limited micro-source, modeling of small signal are studied mainly.Some key issues including demand of dc voltage constant, over modulation, dc voltage fluctuation, dimension reduction and discrete model, influence of dead band and the others are solved primarily.The goal of the project is to develop a new type of microgrid with high-performance. So it proposes a new series microgrid structure , some new methods and strategies of micro-source inverters control, power optimization balance and voltage stability in series microgrids, which provide a new approach for the microgrid networking.

英文关键词： microgrids;inverters in series;power control;harmonic;stability