光伏系统中静止无功发生器的仿真研究
发布时间：2018-12-28 07:51
【摘要】：因全球工业经济的快速发展,地球上的一次能源随之减少,能源危机和环境污染问题愈加严峻。作为新能源之一的太阳能,因具有独特的优势成为理想的替代能源,成为新能源开发中研究的热点之一。随着光伏系统的不断发展,光伏并网逐渐普遍,而并网对电力系统造成的不利影响也越加明显。无功补偿作为改善光伏系统并网电能质量,提高系统稳定运行的重要措施,广泛的应用于光伏系统中。对光伏系统中无功补偿装置的要求是,当电网发生故障时,光伏仍保持并网运行,不从电网吸收功率而是向系统输入无功功率来帮助系统恢复。因为静止无功发生器的优良性能,所以已经成为近些年来无功补偿装置的主要发展方向。以三相光伏并网发电系统为整体,分析了光伏电池的特性,并对最大功率跟踪点和并网逆变控制技术进行了详细介绍。在MATLAB中建立了仿真模型,搭建了系统的各个子模块模型,为分析静止无功发生器在光伏系统正常运行和故障时的补偿效果的仿真打下基础。另一方面,以静止无功发生器(SVG)为整体。对其工作原理进行阐明分析,并详细的分析了对于无功电流检测和控制策略的各种方法。通过比较直接电流和间接电流控制,对于控制系统的设计,采用了两相旋转dq坐标数学模型。在此基础上,对电压电流进行了前馈解耦,以便于完成有功无功的单独控制。因此采用了基于电压电流双环负反馈控制的结构形式,以达到稳定并网点电压和直流侧电压为控制目的的目标。因为发生三相短路故障时,传统的PI控制其相应参数无法自行改变,而作出相应的有效调节。所以引入模糊控制理论对PI调节进行改进,提高三相短路时SVG无功补偿的控制效果。最终的控制方法兼具模糊控制和PI控制的优点,可以根据不同状态下负载的变化而实时发出或吸收无功功率。最后在MATLAB中搭建了含有光伏发电系统的电网整体仿真模型,分别对不同性质的负载进行无功补偿前后效果的仿真对比分析。再对系统中突然增加负载的情况进行仿真,验证模糊PI控制的实时性和有效性。通过对仿真结果的对比分析证明了静止无功发生器良好的动态补偿性能,可以有效提高光伏系统的功率因数,同时对系统节点电压起到稳定的作用。
[Abstract]:With the rapid development of the global industrial economy, the primary energy on the earth has been reduced, and the energy crisis and environmental pollution have become more and more serious. As one of the new energy sources, solar energy has become an ideal alternative energy because of its unique advantages, and has become one of the hot spots in the development of new energy. With the continuous development of photovoltaic system, grid-connected photovoltaic system is becoming more and more common, and the negative impact of grid-connected power system is becoming more and more obvious. Reactive power compensation is widely used in photovoltaic system as an important measure to improve the power quality of grid-connected photovoltaic system and to improve the stable operation of the system. The requirement of the reactive power compensator in the photovoltaic system is that when the power grid fails, the photovoltaic system will still run grid-connected, and instead of absorbing the power from the grid, it will input the reactive power to the system to help the system recover. Because of the excellent performance of static var generator, it has become the main development direction of reactive power compensator in recent years. Taking the three-phase photovoltaic grid-connected generation system as a whole, the characteristics of photovoltaic cells are analyzed, and the maximum power tracking point and grid-connected inverter control technology are introduced in detail. The simulation model is established in MATLAB, and each sub-module model of the system is set up, which lays a foundation for the simulation of the compensation effect of the static Var Generator in the normal operation and failure of the photovoltaic system. On the other hand, the static Var Generator (SVG) is taken as a whole. The principle of reactive current detection and control strategy are analyzed in detail. By comparing direct and indirect current control, a two-phase rotating dq coordinate mathematical model is used for the design of the control system. On this basis, feedforward decoupling of voltage and current is carried out to facilitate the control of active power and reactive power. Therefore, the structure of double loop negative feedback control based on voltage and current is adopted to achieve the goal of stable node voltage and DC side voltage. Because the traditional PI control parameters can not be changed by themselves when the three-phase short circuit fault occurs, the corresponding effective adjustment can be made. So the fuzzy control theory is introduced to improve the PI regulation to improve the control effect of SVG reactive power compensation under three phase short circuit. The final control method has the advantages of both fuzzy control and PI control. It can emit or absorb reactive power in real time according to the variation of load in different states. Finally, the whole simulation model of power grid with photovoltaic generation system is built in MATLAB, and the simulation results before and after reactive power compensation of different properties of load are compared and analyzed respectively. The real time and effectiveness of fuzzy PI control are verified by simulation of the sudden increase of load in the system. The simulation results show that the static Var generator has good dynamic compensation performance, which can effectively improve the power factor of photovoltaic system and stabilize the node voltage of the system.
【学位授予单位】：东北农业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM615;TM761.12
，
本文编号：2393697
[Abstract]:With the rapid development of the global industrial economy, the primary energy on the earth has been reduced, and the energy crisis and environmental pollution have become more and more serious. As one of the new energy sources, solar energy has become an ideal alternative energy because of its unique advantages, and has become one of the hot spots in the development of new energy. With the continuous development of photovoltaic system, grid-connected photovoltaic system is becoming more and more common, and the negative impact of grid-connected power system is becoming more and more obvious. Reactive power compensation is widely used in photovoltaic system as an important measure to improve the power quality of grid-connected photovoltaic system and to improve the stable operation of the system. The requirement of the reactive power compensator in the photovoltaic system is that when the power grid fails, the photovoltaic system will still run grid-connected, and instead of absorbing the power from the grid, it will input the reactive power to the system to help the system recover. Because of the excellent performance of static var generator, it has become the main development direction of reactive power compensator in recent years. Taking the three-phase photovoltaic grid-connected generation system as a whole, the characteristics of photovoltaic cells are analyzed, and the maximum power tracking point and grid-connected inverter control technology are introduced in detail. The simulation model is established in MATLAB, and each sub-module model of the system is set up, which lays a foundation for the simulation of the compensation effect of the static Var Generator in the normal operation and failure of the photovoltaic system. On the other hand, the static Var Generator (SVG) is taken as a whole. The principle of reactive current detection and control strategy are analyzed in detail. By comparing direct and indirect current control, a two-phase rotating dq coordinate mathematical model is used for the design of the control system. On this basis, feedforward decoupling of voltage and current is carried out to facilitate the control of active power and reactive power. Therefore, the structure of double loop negative feedback control based on voltage and current is adopted to achieve the goal of stable node voltage and DC side voltage. Because the traditional PI control parameters can not be changed by themselves when the three-phase short circuit fault occurs, the corresponding effective adjustment can be made. So the fuzzy control theory is introduced to improve the PI regulation to improve the control effect of SVG reactive power compensation under three phase short circuit. The final control method has the advantages of both fuzzy control and PI control. It can emit or absorb reactive power in real time according to the variation of load in different states. Finally, the whole simulation model of power grid with photovoltaic generation system is built in MATLAB, and the simulation results before and after reactive power compensation of different properties of load are compared and analyzed respectively. The real time and effectiveness of fuzzy PI control are verified by simulation of the sudden increase of load in the system. The simulation results show that the static Var generator has good dynamic compensation performance, which can effectively improve the power factor of photovoltaic system and stabilize the node voltage of the system.
【学位授予单位】：东北农业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM615;TM761.12
，
本文编号：2393697
本文链接：https://www.wllwen.com/kejilunwen/dianlidianqilunwen/2393697.html
