模块化多电平静止同步补偿器参数设计及运行控制研究
发布时间：2018-08-06 09:18
【摘要】：电力系统的稳定性问题是电力工业最基本的核心问题,为了保证电力系统可靠运行,系统的电压需在所要求的范围内运行。电压水平的控制是通过系统中无功功率的产生、吸收和传输完成的,由于无功功率不能长距离传输,电压只能通过遍布整个系统的具体装置来进行有效控制。静止同步补偿器(Static Synchronous Compensator,STATCOM)作为柔性交流输电技术在实践中的重要成果之一,具有优良的动态补偿性能,成为无功补偿领域的研究热点。模块化多电平换流器(Modular Multilevel Converter,MMC)是多电平电压型换流器技术的最新研究成果,其标准的模块化结构既便于冗余设计,增强应对故障的能力,又能降低开关频率,提高输出性能。将MMC结构应用到STATCOM中,作为全新的动态无功补偿装置MMC-STATCOM具有良好前景。论文重点对MMC-STATCOM的参数设计和控制策略进行研究,主要工作如下:(1)分析MMC-STATCOM的工作原理,针对MMC具有分散电容和桥臂电感的结构特点,建立abc静止坐标和dq旋转坐标下的等效数学模型。在此基础上,对MMCSTATCOM主要元件(桥臂电感、连接电感、子模块电容和功率器件)的运行特性进行分析,分别得出参数取值范围,以保证MMC-STATCOM的可靠稳定运行。同时,分析电感和电容对系统动态响应速度的综合影响,推导系统开环响应时间和桥臂电感、连接电感、直流电容的关系表达式,为设计满足系统动态性能指标的参数提供依据。(2)研究MMC-STATCOM的整体控制策略。交流侧调制部分,根据MMC-STATCOM桥臂串联子模块个数的不同,分析载波移相脉宽调制(Carrier Phase-Shifted PWM,CPSPWM)在MMC-STATCOM中的具体实现方法。电容电压控制部分,分析修改CPS-PWM调制波实现电容电压平衡的原理,采用分级均压控制方法。环流抑制部分,为了消除环流中的各偶次谐波,引入重复控制,针对传统并联式重复控制器难以独立设计参数的缺点,分析重复控制器传递函数的数学特性,对该并联结构进行合理简化。结合环流中仅含有偶次谐波这一特点,提出一种改进的环流抑制方法,优化控制器性能。(3)在MATLAB/Simulink平台上搭建仿真模型,验证MMC-STATCOM整体控制策略的正确性和有效性,分别对电容均压方法、环流谐波抑制方法和综合补偿性能进行分析。在此基础上,设计驱动控制系统的硬件电路和软件算法。
[Abstract]:The stability of power system is the most basic core problem in power industry. In order to ensure the reliable operation of power system, the voltage of power system needs to operate within the required range. The control of voltage level is accomplished by the generation, absorption and transmission of reactive power in the system. Because reactive power can not be transmitted over long distance, the voltage can only be effectively controlled by a specific device all over the system. As one of the important achievements of flexible AC transmission technology, static synchronous compensator (Static Synchronous compensator Statcom) has excellent dynamic compensation performance and has become a research hotspot in the field of reactive power compensation. Modular multilevel converter (Modular Multilevel converter MMC) is the latest research result of multilevel voltage converter technology. Its standard modular structure is not only convenient for redundant design, but also can reduce switching frequency and improve output performance. The application of MMC structure in STATCOM has a good prospect as a new dynamic reactive power compensator (MMC-STATCOM). This paper focuses on the parameter design and control strategy of MMC-STATCOM. The main work is as follows: (1) analyzing the working principle of MMC-STATCOM, aiming at the structure characteristics of MMC with dispersed capacitance and bridge arm inductance. The equivalent mathematical models of abc stationary coordinate and dq rotation coordinate are established. On this basis, the operating characteristics of the main components of MMCSTATCOM (bridge arm inductance, connecting inductor, submodule capacitance and power device) are analyzed, and the range of parameters are obtained to ensure the reliable and stable operation of MMC-STATCOM. At the same time, the comprehensive influence of inductance and capacitance on the dynamic response speed of the system is analyzed, and the expressions of the open loop response time, the inductance of the bridge arm, the connecting inductor and the DC capacitance are derived. It provides the basis for designing parameters that meet the dynamic performance index of the system. (2) the overall control strategy of MMC-STATCOM is studied. In the AC side modulation part, according to the different number of the series sub-modules of the MMC-STATCOM bridge arm, the realization method of the carrier phase-shifted pulse width modulation (Carrier Phase-Shifted) in the MMC-STATCOM is analyzed. In the part of capacitive voltage control, the principle of realizing capacitor voltage balance by modifying CPS-PWM modulation wave is analyzed, and the stepwise voltage sharing control method is adopted. In order to eliminate the even harmonics in the circulation, the repetitive control is introduced. Aiming at the disadvantage of the traditional parallel repetitive controller that it is difficult to design the parameters independently, the mathematical characteristics of the transfer function of the repetitive controller are analyzed. The parallel structure is reasonably simplified. Combined with the fact that the circulation contains only even harmonics, an improved method of loop suppression is proposed to optimize the performance of the controller. (3) the simulation model is built on the MATLAB/Simulink platform to verify the correctness and effectiveness of the overall control strategy of MMC-STATCOM. The capacitive voltage equalization method, the current harmonic suppression method and the comprehensive compensation performance are analyzed respectively. On this basis, the hardware circuit and software algorithm of the drive control system are designed.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM761.12
[Abstract]:The stability of power system is the most basic core problem in power industry. In order to ensure the reliable operation of power system, the voltage of power system needs to operate within the required range. The control of voltage level is accomplished by the generation, absorption and transmission of reactive power in the system. Because reactive power can not be transmitted over long distance, the voltage can only be effectively controlled by a specific device all over the system. As one of the important achievements of flexible AC transmission technology, static synchronous compensator (Static Synchronous compensator Statcom) has excellent dynamic compensation performance and has become a research hotspot in the field of reactive power compensation. Modular multilevel converter (Modular Multilevel converter MMC) is the latest research result of multilevel voltage converter technology. Its standard modular structure is not only convenient for redundant design, but also can reduce switching frequency and improve output performance. The application of MMC structure in STATCOM has a good prospect as a new dynamic reactive power compensator (MMC-STATCOM). This paper focuses on the parameter design and control strategy of MMC-STATCOM. The main work is as follows: (1) analyzing the working principle of MMC-STATCOM, aiming at the structure characteristics of MMC with dispersed capacitance and bridge arm inductance. The equivalent mathematical models of abc stationary coordinate and dq rotation coordinate are established. On this basis, the operating characteristics of the main components of MMCSTATCOM (bridge arm inductance, connecting inductor, submodule capacitance and power device) are analyzed, and the range of parameters are obtained to ensure the reliable and stable operation of MMC-STATCOM. At the same time, the comprehensive influence of inductance and capacitance on the dynamic response speed of the system is analyzed, and the expressions of the open loop response time, the inductance of the bridge arm, the connecting inductor and the DC capacitance are derived. It provides the basis for designing parameters that meet the dynamic performance index of the system. (2) the overall control strategy of MMC-STATCOM is studied. In the AC side modulation part, according to the different number of the series sub-modules of the MMC-STATCOM bridge arm, the realization method of the carrier phase-shifted pulse width modulation (Carrier Phase-Shifted) in the MMC-STATCOM is analyzed. In the part of capacitive voltage control, the principle of realizing capacitor voltage balance by modifying CPS-PWM modulation wave is analyzed, and the stepwise voltage sharing control method is adopted. In order to eliminate the even harmonics in the circulation, the repetitive control is introduced. Aiming at the disadvantage of the traditional parallel repetitive controller that it is difficult to design the parameters independently, the mathematical characteristics of the transfer function of the repetitive controller are analyzed. The parallel structure is reasonably simplified. Combined with the fact that the circulation contains only even harmonics, an improved method of loop suppression is proposed to optimize the performance of the controller. (3) the simulation model is built on the MATLAB/Simulink platform to verify the correctness and effectiveness of the overall control strategy of MMC-STATCOM. The capacitive voltage equalization method, the current harmonic suppression method and the comprehensive compensation performance are analyzed respectively. On this basis, the hardware circuit and software algorithm of the drive control system are designed.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM761.12
【参考文献】
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