光伏逆变器并联问题的研究

发布时间：2018-04-17 07:18

本文选题：光伏发电 + 逆变器　；参考：《辽宁工业大学》2014年硕士论文

【摘要】：随着能源和环境问题越来越突出，光伏发电作为一种战略性新兴产业，得到了快速发展。光伏发电系统的并网问题是当今光伏发电研究的热门方向之一，随着社会的发展和用电量需求的增加，许多负载设备对功率容量的要求越来越大，由于单模块逆变器的扩充性和可靠性在实际应用当中会受到很大的限制，所以设计多模块逆变器并联再并网发电显得尤为重要。对于逆变器并联均流控制的方法，过去已经提出了许多具有不同复杂程度和均流性能的控制方法。由系统中各模块是否需要通过互连线进行通信，可划分为有线并联控制方式和无互连线并联控制方式。随着逆变器并联技术的迅速发展和不断成熟，高可靠性、高冗余度、智能化控制是主要发展方向，相对于有互连线并联系统来说，无互连线并联由于各模块之间不需要信号的传输线而大大提高了抗干扰能力和可靠性。目前常用的无线并联控制方式为下垂法，通过调整输出功率来调节模块输出电压。首先介绍了目前各国能源问题的现状，引出太阳能发电的意义和发展空间，进一步分析光伏逆变器对于光伏发电系统的重要性。详细研究了逆变器的主电路结构和工作原理。其次通过仿真模型的建立，分析并联系统环流产生的原因，并对无并联控制策略的双闭环控制逆变器并联系统进行仿真分析，通过仿真结果得出控制参数对并联系统均流性能的影响。然后分析分布式控制策略对并联系统均流效果的调节作用，通过公式的推导和仿真实验的结果得出分布式并联控制策略可以很好的抑制系统环流，并改善电路的稳态和动态性能。最后引入了双环控制逆变器并联系统的下垂法控制策略，通过分析并联逆变器的环流特征，对采用传统下垂法的并联系统进行仿真，结果表明传统下垂法能够实现均流和功率均分，，但同时也会使系统的输出特性变软。进一步分析可知引入功率的微分项可以改善输出外特性和系统的动态性能。
[Abstract]:As energy and environmental problems become more and more prominent, photovoltaic power generation as a strategic emerging industry, has been rapid development.The grid-connected problem of photovoltaic power generation system is one of the hot research directions of photovoltaic power generation nowadays. With the development of society and the increasing demand for electricity consumption, many load equipments require more and more power capacity.Because the expansibility and reliability of single-module inverter will be limited in practical application, it is very important to design multi-module inverter in parallel and connected to grid.For the parallel current sharing control of inverter, many control methods with different complexity and current sharing performance have been put forward in the past.Whether each module in the system needs to communicate through interconnection lines can be divided into wired parallel control mode and no interconnection parallel control mode.With the rapid development and maturity of parallel inverter technology, high reliability, high redundancy, intelligent control is the main development direction, compared with the interconnection parallel system,The non-interconnect parallel connection greatly improves the anti-interference ability and reliability because the transmission lines between the modules do not need signal.At present, the commonly used wireless parallel control method is droop method, which adjusts the output voltage of the module by adjusting the output power.Firstly, the paper introduces the current situation of energy problems in various countries, leads to the significance and development space of solar power generation, and further analyzes the importance of photovoltaic inverter to photovoltaic power generation system.The main circuit structure and working principle of inverter are studied in detail.Secondly, through the establishment of simulation model, the causes of the circulation of parallel system are analyzed, and the parallel system of double closed loop control inverter without parallel control strategy is simulated and analyzed.The effect of control parameters on the current sharing performance of parallel system is obtained by simulation results.Then it analyzes the regulation effect of distributed control strategy on the current sharing effect of parallel system. Through the derivation of formula and the result of simulation experiment, it is concluded that the distributed parallel control strategy can restrain the circulation of the system very well.The steady and dynamic performance of the circuit is improved.Finally, the droop control strategy of the double-loop inverter parallel system is introduced. By analyzing the circulation characteristics of the parallel inverter, the parallel system using the traditional droop method is simulated.The results show that the traditional droop method can achieve current sharing and power sharing, but it can also soften the output characteristics of the system.Further analysis shows that the micro-subdivision of power can improve the output characteristics and the dynamic performance of the system.
【学位授予单位】：辽宁工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM464;TM615

【参考文献】