光伏逆变并网控制系统研究与实现

发布时间：2018-06-28 21:56

本文选题：并网控制 + SVPWM　；参考：《电子科技大学》2014年硕士论文

【摘要】：近年来,随着世界能源危机的加剧,环境日益恶化,新能源的发展和利用受到各国政府的高度关注,新能源技术的研究备受各国专家关注。光伏逆变器作为利用新能源的一种重要分布式发电形式,微电网的重要组成部分,其并网控制系统研究受到广泛关注。本文以三相光伏逆变的并网控制系统作为设计对象,以提高并网控制系统的稳定性,动态性能,稳态性能,提高输出并网输出电流质量等为目的,对并网控制系统进行研究和分析。首先,本文分析了光伏逆变器的并网原理,在并网原理的基础上,引入了SVPWM(空间矢量脉宽调制)开关控制技术;详细阐述了SVPWM开关控制技术的理论基础,并基于三相交流电流在三相电机中的合成磁动势等效原理,严密推导了三相交流电流以及三相交流电压从三相静止坐标系转换两相旋转坐标系的坐标变转化过程;研究了正弦参考电压由基本矢量合成方法,设计了扇区判断的索引值确定方法;简述了SVPWM波的DSP实现,实现了将对三相交流电流的控制转换为对直流电流的控制。其次,本文基于并网模型,在SVPWM开关控制方法的基础上,对系统进行建模分析。针对由坐标变换引起的有功电流和无功电流耦合的现象,本文引入了系统前馈解耦设计方法,消除了耦合,减小了系统控制难度;对电网电压扰动进了前馈补偿设计,消除了其对系统稳态误差的影响;引入PI前向串联设计,分析了PI参数对系统调节的原理。然后,本文对并网控制系统的稳态性,动态性能和稳定性能进行了分析,对比了PI参数变化、系统硬件参数变化对系统性能的影响;由于仅采用PI控制器设计的控制系统在理论上无法完全消除系统稳态误差,引入了重复控制器;在分析重复控制器的基础上,根据系统需要,改进了重复控制器结构;设计了重复控制和PI控制相结合的控制系统。最后,本文构建了控制系统的MATLAB仿真模型,验证了该系统各模块功能的正确性;同时在硬件平台上对本文设计的控制系统进行了对比实验测试。测试结果显示系统在满功率1500W工作时,功率因素为0.99,输出电能的谐波因数为1.8%。测试结果表明本设计对并网电流的控制效果良好,精度高。
[Abstract]:In recent years, with the aggravation of the world energy crisis and the worsening of the environment, the development and utilization of new energy are highly concerned by the governments of all countries, and the research of new energy technology has attracted the attention of experts. As an important form of distributed generation using new energy, photovoltaic inverter (PV) is an important part of microgrid, and its grid-connected control system has been paid more and more attention. In this paper, three-phase photovoltaic inverter grid-connected control system is designed to improve the stability, dynamic performance, steady-state performance of the grid-connected control system, and improve the quality of output grid-connected output current, etc. Research and analysis of grid-connected control system. Firstly, this paper analyzes the grid-connected principle of photovoltaic inverter, introduces SVPWM (Space Vector Pulse width Modulation) switch control technology on the basis of grid-connected principle, and expounds the theoretical basis of SVPWM switch control technology in detail. Based on the equivalent principle of three-phase AC current in three-phase motor, the coordinate transformation process of three-phase AC current and three-phase AC voltage from three-phase static coordinate system to two-phase rotating coordinate system is deduced. The method of synthesizing sinusoidal reference voltage by basic vector is studied, the method of determining the index value of sector judgment is designed, and the DSP realization of SVPWM wave is briefly described, which can convert the control of three-phase AC current into the control of DC current. Secondly, based on grid-connected model and SVPWM switch control method, the system is modeled and analyzed. Aiming at the coupling of active current and reactive current caused by coordinate transformation, the feedforward decoupling design method is introduced in this paper, which eliminates the coupling and reduces the difficulty of system control. The influence of Pi parameters on the steady-state error of the system is eliminated, and the principle of Pi parameters regulating the system is analyzed by introducing Pi forward series design. Then, the steady-state, dynamic and stable performance of grid-connected control system is analyzed, and the effects of Pi parameters and hardware parameters on system performance are compared. Since the control system designed only with Pi controller can not completely eliminate the steady-state error of the system theoretically, the repetitive controller is introduced, and the repetitive controller structure is improved according to the need of the system by analyzing the repetitive controller. A control system combining repetitive control and Pi control is designed. Finally, the MATLAB simulation model of the control system is constructed, which verifies the correctness of the function of each module of the control system. At the same time, the control system designed in this paper is tested and compared on the hardware platform. The test results show that the power factor is 0.99 and the harmonic factor is 1.8 when the full power is 1500 W. The test results show that this design has good control effect and high precision for grid-connected current.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM615;TM464

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