基于虚拟同步发电机功率控制策略的光伏发电系统研究
发布时间：2018-07-25 13:57
【摘要】：太阳能光伏并网发电技术是目前新能源研究开发热点之一，，促使其得到了快速发展和越来越广泛的应用。然而，光伏发电系统与传统发电方式存在很大差异，其大规模应用的负面影响引起越来越多研究人员的关注。同步发电机具有较好的组网特性，使光伏发电系统模拟同步发电机特性将有效避免光伏发电规模化应用存在的隐患，对光伏发电技术发展具有重要意义。 本文首先对光伏发电系统工作原理及系统结构进行了分析介绍，针对采用L型和LC型滤波器的光伏逆变器数学模型进行了推导和相应控制策略的分析，对储能技术在光伏发电系统中应用方式进行了介绍，为下文结合光伏与储能实现虚拟同步发电机控制技术的研究打下基础。 基于同步发电机二阶模型建立了虚拟同步发电机(VSG，Virtual SynchonousGenerator)算法，对其基本特性及虚拟惯性作用进行了详细分析。分析了采用无功功率闭环控制时控制器参数对系统特性的影响，并设计了一种基于坐标变换实现有功无功解耦的无功功率控制方法，可以避免有功无功功率输出特性相互影响。针对VSG算法实现，提出一种基于VSG算法的功率控制策略，通过该方法可使光伏发电系统有效模拟同步发电机特性，同时避免VSG算法的应用增加系统控制复杂度和降低系统可靠性的问题。 在对VSG算法的研究基础上，将该控制技术应用至微电网运行控制中，结合两种VSG算法实现方式对微电网分布式光伏电源进行控制，从而使它们均具有双模式运行和微电网孤岛运行模式下的负荷自动分配能力，并实现了微电网的灵活控制。对微电网孤岛运行模式下频率调整和电压控制策略进行了分析和设计，并针对微电网模式切换提出了一种基于虚拟功率的预同步控制策略，可以在不检测频率、相位情况下实现微电网与主网的预同步控制。 最后，在MATLAB/Simulink中建立了系统仿真模型，仿真结果表明：(1)应用VSG算法的光伏发电系统具有了虚拟惯性，基于坐标变换解耦的无功功率控制实现了很好的控制效果，且避免了对系统动态特性的影响；(2)通过功率控制实现VSG算法的方法达到了引入虚拟惯性目的，且系统具有较好的可靠性；(3)基于VSG控制技术的微电网分布式光伏电源协调控制策略实现了微电网的可靠运行，基于虚拟功率的预同步控制策略可实现微电网母线电压与主电网电压的准确同步。
[Abstract]:Solar photovoltaic grid-connected power generation technology is one of the hot spots in the research and development of new energy at present, which promotes its rapid development and more extensive application. However, there is a great difference between photovoltaic power generation system and traditional power generation methods, and the negative effects of its large-scale application have attracted more and more researchers' attention. Synchronous generators have better networking characteristics, so that the photovoltaic system simulation synchronous generator characteristics will effectively avoid the potential problems existing in the large-scale application of photovoltaic power generation, which is of great significance for the development of photovoltaic power generation technology. In this paper, the working principle and system structure of photovoltaic power generation system are analyzed and introduced, and the mathematical model of photovoltaic inverter using L-type and LC filter is deduced and the corresponding control strategy is analyzed. The application of energy storage technology in photovoltaic power generation system is introduced, which lays a foundation for the research of virtual synchronous generator control technology combined with photovoltaic and energy storage. Based on the second order model of synchronous generator, the algorithm of virtual synchronous generator (VSG) is established, and its basic characteristics and virtual inertial action are analyzed in detail. This paper analyzes the influence of controller parameters on system characteristics when reactive power closed-loop control is adopted, and designs a reactive power control method based on coordinate transformation to realize active and reactive power decoupling, which can avoid the mutual influence of active and reactive power output characteristics. For the realization of VSG algorithm, a power control strategy based on VSG algorithm is proposed, by which the photovoltaic power generation system can effectively simulate the characteristics of synchronous generator. At the same time, the application of VSG algorithm can increase the complexity of system control and reduce the reliability of the system. Based on the research of VSG algorithm, the control technology is applied to the operation control of microgrid, and the distributed photovoltaic power supply of microgrid is controlled by two VSG algorithms. Therefore, both of them have the ability of automatic load distribution under the mode of dual mode operation and isolated island mode of microgrid, and the flexible control of microgrid is realized. This paper analyzes and designs the frequency adjustment and voltage control strategy in isolated island operation mode of microgrid, and proposes a presynchronous control strategy based on virtual power, which can detect frequency without detection. In the case of phase, the presynchronous control between microgrid and main network is realized. Finally, the system simulation model is established in MATLAB/Simulink. The simulation results show that: (1) the photovoltaic power generation system using VSG algorithm has virtual inertia, and the reactive power control based on the decoupling of coordinate transformation achieves a good control effect. It avoids the influence on the dynamic characteristics of the system. (2) the method of realizing VSG algorithm by power control achieves the purpose of introducing virtual inertia and the system has good reliability. (3) the coordinated control strategy of distributed photovoltaic power supply based on VSG technology realizes the reliable operation of microgrid, and the presynchronous control strategy based on virtual power can realize the accurate synchronization of bus voltage and main grid voltage.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM615
本文编号：2144035
[Abstract]:Solar photovoltaic grid-connected power generation technology is one of the hot spots in the research and development of new energy at present, which promotes its rapid development and more extensive application. However, there is a great difference between photovoltaic power generation system and traditional power generation methods, and the negative effects of its large-scale application have attracted more and more researchers' attention. Synchronous generators have better networking characteristics, so that the photovoltaic system simulation synchronous generator characteristics will effectively avoid the potential problems existing in the large-scale application of photovoltaic power generation, which is of great significance for the development of photovoltaic power generation technology. In this paper, the working principle and system structure of photovoltaic power generation system are analyzed and introduced, and the mathematical model of photovoltaic inverter using L-type and LC filter is deduced and the corresponding control strategy is analyzed. The application of energy storage technology in photovoltaic power generation system is introduced, which lays a foundation for the research of virtual synchronous generator control technology combined with photovoltaic and energy storage. Based on the second order model of synchronous generator, the algorithm of virtual synchronous generator (VSG) is established, and its basic characteristics and virtual inertial action are analyzed in detail. This paper analyzes the influence of controller parameters on system characteristics when reactive power closed-loop control is adopted, and designs a reactive power control method based on coordinate transformation to realize active and reactive power decoupling, which can avoid the mutual influence of active and reactive power output characteristics. For the realization of VSG algorithm, a power control strategy based on VSG algorithm is proposed, by which the photovoltaic power generation system can effectively simulate the characteristics of synchronous generator. At the same time, the application of VSG algorithm can increase the complexity of system control and reduce the reliability of the system. Based on the research of VSG algorithm, the control technology is applied to the operation control of microgrid, and the distributed photovoltaic power supply of microgrid is controlled by two VSG algorithms. Therefore, both of them have the ability of automatic load distribution under the mode of dual mode operation and isolated island mode of microgrid, and the flexible control of microgrid is realized. This paper analyzes and designs the frequency adjustment and voltage control strategy in isolated island operation mode of microgrid, and proposes a presynchronous control strategy based on virtual power, which can detect frequency without detection. In the case of phase, the presynchronous control between microgrid and main network is realized. Finally, the system simulation model is established in MATLAB/Simulink. The simulation results show that: (1) the photovoltaic power generation system using VSG algorithm has virtual inertia, and the reactive power control based on the decoupling of coordinate transformation achieves a good control effect. It avoids the influence on the dynamic characteristics of the system. (2) the method of realizing VSG algorithm by power control achieves the purpose of introducing virtual inertia and the system has good reliability. (3) the coordinated control strategy of distributed photovoltaic power supply based on VSG technology realizes the reliable operation of microgrid, and the presynchronous control strategy based on virtual power can realize the accurate synchronization of bus voltage and main grid voltage.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM615
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