逆变型微电网电能质量控制研究

发布时间：2018-04-27 15:03

本文选题：逆变型微电网 + 电能质量　；参考：《山东大学》2015年硕士论文

【摘要】：大电网与微电网相结合的模式被认为是节省投资,降低能耗,提高供电可靠性和灵活性的重要形式。微电网中的分布式电源(Distributed Generation)可以分为同步型DG和逆变型DG,与同步型DG相比,逆变型DG采用全控的电力电子接口,控制更加灵活,具有巨大的性能优势。逆变型微电网可以综合利用本地优势资源,向用户提供清洁的能源,但传统大电网中的许多电能质量问题如谐波和电压暂降等仍然存在,传统的治理方法是加装APF、DVR等电能质量控制装置进行被动控制。考虑到逆变型DG并网逆变器与传统的电能质量控制装置具有相同的主电路结构,因此,可以利用逆变型DG在并网发电的同时对电能质量进行主动控制,这样充分发挥了逆变型DG控制灵活的特点。首先,针对逆变型微电源的基本控制方法进行了研究。在逆变型微电网中,对微电源的控制即为对其逆变器的控制。本文以三相电压型逆变器在两相旋转坐标系中的数学模型为基础,详细分析了逆变型微电源的PQ控制和下垂控制方法的原理,并对相应的控制器参数进行了选择；此外,还针对下垂控制的电压电流双闭环控制系统推导了其逆变器等效输出阻抗的表达式,并绘制逆变器等效输出阻抗伯德图。当微电网与低压配电网相连时,传统的下垂控制由于等效输出阻抗过小不能满足XR而不在适用,通过引入虚拟阻抗,使逆变器等效输出阻抗足够大且呈感性。建立逆变型微电网仿真模型,针对单个逆变型微电源和微电源组网状态下的运行情况进行了仿真,验证了PQ控制模型和基于虚拟阻抗的下垂控制模型的有效性。其次,针对微电网中的谐波治理问题进行了研究。分析了传统的谐波治理装置APF的结构、原理和电流跟踪控制方法；分析了二阶广义积分器的基本原理,并将基于二阶广义积分器的谐波电流检测方法应用于并网逆变器控制之中,搭建了逆变型微电网谐波治理的主动控制模型,通过仿真验证了主动控制在微电网谐波治理方面能够起到一定的作用,并且主动控制的并网逆变器能够实现无功功率的就地平衡以及改善微网电流不平衡的功能。当微电网输出电流在主动控制下仍不能满足谐波标准时,加装APF对微电网谐波进行被动控制。最后,针对逆变型微电网中的电压暂降补偿问题进行了研究。分析了传统的电压暂降补偿装置DVR的结构原理及控制方式；分析了含多台逆变型DG的微电网PCC电压暂降补偿的基本原理及在无功功率分配方面的限制。通过对下垂控制中Q/V控制进行改进实现了电压暂降补偿的主动控制,同时实现了输出无功功率按容量比例进行分配而不受线路阻抗的影响。搭建了逆变型微电网电压暂降补偿主动控制的仿真模型,仿真结果表明在主动控制方式下,微电源能够在并网发电的同时对PCC电压暂降进行补偿。当PCC电压暂降超过一定程度,过分增加DG输出无功功率既不经济也不实用,通过控制DG输出电压,同时加装DVR对微电网敏感负荷电压暂降进行被动控制,仿真表明通过主动控制与被动控制相结合的方式能够实现微电网负荷电压不受电压暂降的影响。
[Abstract]:The combination of large power grid and Microgrid is considered as an important form of saving investment, reducing energy consumption and improving power supply reliability and flexibility. The distributed power supply (Distributed Generation) in microgrid can be divided into synchronous DG and inverter type DG. Compared with synchronous DG, the reverse variant DG uses a fully controlled power electronic interface, and the control is more flexible. The inverter type micro grid can make use of local advantages and provide clean energy to users. However, many power quality problems in traditional large power grid, such as harmonic and voltage temporary degradation, are still existing, the traditional method is to install APF, DVR and other power quality control devices for passive control. The inverter type DG grid inverter and the traditional power quality control device have the same main circuit structure. Therefore, the inverter type DG can take active control of the power quality at the same time when the inverter is connected to the grid, which fully plays the flexible characteristics of the inverter DG control. First, the basic control method of the inverter type micro power supply is studied. In the inverter type microgrid, the control of the micro power supply is the control of the inverter. Based on the mathematical model of the three-phase voltage inverter in the two phase rotating coordinate system, the principle of the PQ control and the droop control method of the inverter micro power supply is analyzed in detail, and the corresponding controller parameters are selected. In addition, the controller is also selected. The expression of the equivalent output impedance of the inverter is derived for the voltage and current double closed loop control system with droop control, and the equivalent output impedance Bode diagram of the inverter is drawn. When the micro grid is connected with the low-voltage distribution network, the traditional droop control is not suitable for XR because the equivalent output impedance is too small, and the virtual impedance is introduced. The equivalent output impedance of the inverter is large enough and sensibility. The simulation model of the inverter type microgrid is set up. The simulation of the operation of the single inverter and the micro power supply is carried out. The validity of the PQ control model and the droop control model based on the virtual impedance is verified. Secondly, the harmonic governance in the microgrid is asked. The structure, the principle and the current tracking control method of the traditional harmonic control device APF are analyzed, the basic principle of the Nikai Hiroyoshi integrator is analyzed, and the harmonic current detection method based on the Nikai Hiroyoshi integrator is applied to the control of the grid connected inverter, and the active control of the harmonic control of the inverter type microgrid is built. The simulation shows that the active control plays a certain role in the harmonic control of the microgrid, and the active control of the grid connected inverter can achieve the in-situ balance of reactive power and the function of improving the imbalance of the microgrid current. When the output current of the microgrid can not meet the harmonics standard under the main dynamic control, the A is added. PF has passive control on the harmonics of microgrid. Finally, the problem of voltage sags compensation in the inverter type microgrid is studied. The structure principle and control mode of the traditional voltage sags compensation device DVR are analyzed. The basic principle of the voltage sags compensation of the microgrid PCC containing multiple inverter DG and the reactive power formula are analyzed. The active control of the voltage sags compensation is realized by improving the Q/V control in the droop control. At the same time, the output reactive power is allocated according to the capacity ratio without the influence of the line impedance. A simulation model for the active control of the inverter type voltage sags compensation is built, and the simulation results show that the active control is in the active control. In the way, the micro power supply can compensate the voltage sags of the PCC at the same time. When the PCC voltage sag exceeds a certain degree, it is neither economical nor practical to increase the DG output reactive power too much. By controlling the output voltage of the DG and adding DVR to the micro grid sensitive load voltage sags, the simulation shows that the active control is carried out through the active control. The load voltage of microgrid can not be affected by voltage sag by combining the system with passive control.

【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM714.2;TM464

【共引文献】