發(fā)布時(shí)間：2018-08-06 09:18

【摘要】：電力系統(tǒng)的穩(wěn)定性問(wèn)題是電力工業(yè)最基本的核心問(wèn)題,為了保證電力系統(tǒng)可靠運(yùn)行,系統(tǒng)的電壓需在所要求的范圍內(nèi)運(yùn)行。電壓水平的控制是通過(guò)系統(tǒng)中無(wú)功功率的產(chǎn)生、吸收和傳輸完成的,由于無(wú)功功率不能長(zhǎng)距離傳輸,電壓只能通過(guò)遍布整個(gè)系統(tǒng)的具體裝置來(lái)進(jìn)行有效控制。靜止同步補(bǔ)償器(Static Synchronous Compensator,STATCOM)作為柔性交流輸電技術(shù)在實(shí)踐中的重要成果之一,具有優(yōu)良的動(dòng)態(tài)補(bǔ)償性能,成為無(wú)功補(bǔ)償領(lǐng)域的研究熱點(diǎn)。模塊化多電平換流器(Modular Multilevel Converter,MMC)是多電平電壓型換流器技術(shù)的最新研究成果,其標(biāo)準(zhǔn)的模塊化結(jié)構(gòu)既便于冗余設(shè)計(jì),增強(qiáng)應(yīng)對(duì)故障的能力,又能降低開(kāi)關(guān)頻率,提高輸出性能。將MMC結(jié)構(gòu)應(yīng)用到STATCOM中,作為全新的動(dòng)態(tài)無(wú)功補(bǔ)償裝置MMC-STATCOM具有良好前景。論文重點(diǎn)對(duì)MMC-STATCOM的參數(shù)設(shè)計(jì)和控制策略進(jìn)行研究,主要工作如下:(1)分析MMC-STATCOM的工作原理,針對(duì)MMC具有分散電容和橋臂電感的結(jié)構(gòu)特點(diǎn),建立abc靜止坐標(biāo)和dq旋轉(zhuǎn)坐標(biāo)下的等效數(shù)學(xué)模型。在此基礎(chǔ)上,對(duì)MMCSTATCOM主要元件(橋臂電感、連接電感、子模塊電容和功率器件)的運(yùn)行特性進(jìn)行分析,分別得出參數(shù)取值范圍,以保證MMC-STATCOM的可靠穩(wěn)定運(yùn)行。同時(shí),分析電感和電容對(duì)系統(tǒng)動(dòng)態(tài)響應(yīng)速度的綜合影響,推導(dǎo)系統(tǒng)開(kāi)環(huán)響應(yīng)時(shí)間和橋臂電感、連接電感、直流電容的關(guān)系表達(dá)式,為設(shè)計(jì)滿足系統(tǒng)動(dòng)態(tài)性能指標(biāo)的參數(shù)提供依據(jù)。(2)研究MMC-STATCOM的整體控制策略。交流側(cè)調(diào)制部分,根據(jù)MMC-STATCOM橋臂串聯(lián)子模塊個(gè)數(shù)的不同,分析載波移相脈寬調(diào)制(Carrier Phase-Shifted PWM,CPSPWM)在MMC-STATCOM中的具體實(shí)現(xiàn)方法。電容電壓控制部分,分析修改CPS-PWM調(diào)制波實(shí)現(xiàn)電容電壓平衡的原理,采用分級(jí)均壓控制方法。環(huán)流抑制部分,為了消除環(huán)流中的各偶次諧波,引入重復(fù)控制,針對(duì)傳統(tǒng)并聯(lián)式重復(fù)控制器難以獨(dú)立設(shè)計(jì)參數(shù)的缺點(diǎn),分析重復(fù)控制器傳遞函數(shù)的數(shù)學(xué)特性,對(duì)該并聯(lián)結(jié)構(gòu)進(jìn)行合理簡(jiǎn)化。結(jié)合環(huán)流中僅含有偶次諧波這一特點(diǎn),提出一種改進(jìn)的環(huán)流抑制方法,優(yōu)化控制器性能。(3)在MATLAB/Simulink平臺(tái)上搭建仿真模型,驗(yàn)證MMC-STATCOM整體控制策略的正確性和有效性,分別對(duì)電容均壓方法、環(huán)流諧波抑制方法和綜合補(bǔ)償性能進(jìn)行分析。在此基礎(chǔ)上,設(shè)計(jì)驅(qū)動(dòng)控制系統(tǒng)的硬件電路和軟件算法。
[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.
【學(xué)位授予單位】：江蘇大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TM761.12

【參考文獻(xiàn)】

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本文編號(hào)：2167268