【作者】 刘淳；

【导师】 张兴；

【作者基本信息】 合肥工业大学 ， 电力电子与电力传动， 2008， 硕士

【摘要】 随着新能源发电传输、不同电网间电力市场交易等新型输电模式的高速发展,传统输电方式已经不能满足这些新型输电模式的应用要求。基于电压源PWM整流器(VSC)技术的柔性直流输电技术是近年来发展起来的一种新型输电模式,拥有能独立控制有功、无功功率、不会增加系统短路容量、可以实现异步电网连接等巨大的优势。柔性直流输电系统的主要作用就是控制不同电网间的潮流传输方向与大小,因此,对柔性直流输电系统换流站的输出瞬时功率计算方法和功率控制策略的研究具有重要意义。本文从建立柔性直流输电换流器数学模型入手,分别建立了基于换流站输出电压幅位、相角的稳态功率模型和基于三相静止、两相旋转坐标系下的换流器数学模型,为功率控制策略分析,控制系统设计,分析提供了理论依据。依据柔性直流输电换流器数学模型,本文结合PWM整流器各种可用于功率控制的控制策略,分别分析了基于电压定向和基于虚拟磁链的瞬时功率计算方式的原理;并分析了基于功率滞环比较器的功率控制方式。在分析的基础上,本文给出了三种柔性直流输电系统控制模型:基于电压定向功率控制模型,基于功率滞环比较器的功率控制模型,基于虚拟磁链的定频功率控制模型。并以电压定向功率控制模型为例详细论述了柔性直流输电系统的控制系统参数设计,详细讨论并对比了三种功率控制模型的优缺点。得出基于虚拟磁链的定频功率控制模型是最适合于柔性直流输电系统功率控制的结论,通过MATLAB/Simulink仿真软件验证了所有分析结果的有效性。完成了15KVA的柔性直流输电系统原理样机的研制,系统稳态特性和动态特性良好,验证了所选控制策略的有效性。更多还原

【Abstract】 With the fast development of new power energy transmission mode like new energy power transmission、transactions in different power grid market, Traditional transmission methods can not meet these new requirements. Based on the Voltage source converter (VSC) technology, the flexible HVDC technology is a highly developing mode of power transmission. It can have huge advantage like the independent control of active, reactive power; do not increase the short-circuit system capacity; asynchronous link between power grids. The main role of flexible HVDC system is to control the direction and size of tide between different power grids, so it is of great significance to research the instantaneous power calculation methods and control strategies in flexible HVDC system.As the establishment of flexible HVDC converter mathematical models start with, we establish the converter ’s steady-state model based on the rate and phrase of output voltage and the mathematical model based on the three-phase power static、two-phase rotating static. So it provides a theoretical basis to power control strategy analysis, control system design and analysis.With the mathematical model of flexible HVDC system, and combine with all kinds of the control strategy of PWM converter, respectively, introduce the methods of instantaneous power calculation based on the analysis of orientation voltage and based on virtual flux of analysis and have analysis of the power control methods based on the hysteretic comparator.In the basis of the analysis, three flexible HVDC system control modes have been given: the control model based on the directional voltage power, the control model based on the power hysteretic comparator, the power-control model based on virtual flux, and discuss them with the advantages and disadvantages in detail. Than have the conclusion that the power-control model of virtual flux is the most suitable for flexible HVDC system, the MATLAB / Simulink simulation results verify the validity of all the analysis results.A 15 KVA of flexible HVDC experimental system is established. The steady state and dynamic system characteristics is good, the results verify the effectiveness of the selected control strategy.更多还原