發(fā)布時(shí)間：2018-07-04 09:04

  本文選題：弱電網(wǎng) + 并網(wǎng)變流器��； 參考：《北京交通大學(xué)》2015年碩士論文

【摘要】：隨著可再生能源的普及,分布式發(fā)電系統(tǒng)成為研究熱點(diǎn),而并網(wǎng)變流器是實(shí)現(xiàn)電網(wǎng)與分布式發(fā)電系統(tǒng)之間能量交換的紐帶。傳統(tǒng)的變流器在設(shè)計(jì)時(shí)是將電網(wǎng)視為理想的電壓源,但在分布式發(fā)電系統(tǒng)中,理想的電網(wǎng)模型將不再適用。實(shí)際的電網(wǎng)會(huì)因線路傳輸阻抗、變壓器漏感等而呈現(xiàn)出弱電網(wǎng)特性。并網(wǎng)變流器與電網(wǎng)之間形成了一個(gè)交互系統(tǒng),變流器與電網(wǎng)之間的交互作用可能會(huì)對(duì)并網(wǎng)系統(tǒng)的穩(wěn)定性產(chǎn)生影響。 本文主要研究弱電網(wǎng)條件下并網(wǎng)變流器的控制策略,具體分析了電網(wǎng)和變流器間阻抗交互作用對(duì)并網(wǎng)系統(tǒng)穩(wěn)定性產(chǎn)生的影響,并選取了適用于弱電網(wǎng)條件下并網(wǎng)變流器的鎖相環(huán)方法。 首先,對(duì)基于阻抗的穩(wěn)定性判據(jù)進(jìn)行了說明,以此作為分析并網(wǎng)交互系統(tǒng)穩(wěn)定性的理論基礎(chǔ)。分別對(duì)采用L和LCL型濾波器的并網(wǎng)變流器輸出阻抗進(jìn)行了建模,由于LCL型濾波器會(huì)給并網(wǎng)變流器系統(tǒng)引入額外的諧振峰繼而使并網(wǎng)系統(tǒng)不穩(wěn)定,本文采用在電容支路串聯(lián)阻尼電阻的無源阻尼方法來抑制LCL諧振峰,增加阻尼以使系統(tǒng)穩(wěn)定。論文在頻域下定量分析了并網(wǎng)變流器與弱電網(wǎng)之間由于阻抗交互作用所產(chǎn)生的諧波諧振問題。理論分析表明,在電網(wǎng)阻抗和變流器阻抗幅值相等處的頻率附近易產(chǎn)生一定程度的諧波諧振,相比于L濾波型變流器,LCL濾波型變流器更容易與弱電網(wǎng)發(fā)生諧波諧振。在時(shí)域下進(jìn)行的仿真驗(yàn)證了理論分析的正確性。 其次,本文選取了基于二階廣義積分器的鎖相環(huán)方法來進(jìn)行鎖相,通過仿真驗(yàn)證了該鎖相環(huán)方法在不同電網(wǎng)條件下鎖相的有效性和準(zhǔn)確性,說明該方法是適用于本文中弱電網(wǎng)條件下三相并網(wǎng)變流器系統(tǒng)的。 最后,搭建了三相并網(wǎng)變流器的實(shí)驗(yàn)平臺(tái),對(duì)弱電網(wǎng)條件下并網(wǎng)變流器系統(tǒng)的穩(wěn)定性分析結(jié)果進(jìn)行了實(shí)驗(yàn)驗(yàn)證,給出了采用不同濾波器時(shí)不同電網(wǎng)條件下的并網(wǎng)電流波形和諧波分析結(jié)果,驗(yàn)證了本文中理論分析和仿真結(jié)果的正確性。
[Abstract]:With the popularization of renewable energy, distributed generation system has become a hot research topic, and grid-connected converter is the link to realize the energy exchange between grid and distributed generation system. The traditional converter is designed as the ideal voltage source, but in the distributed generation system, the ideal power network model will no longer be applicable. The actual power network will show weak network characteristics due to transmission impedance and leakage inductance of transformer. An interactive system is formed between the grid-connected converter and the grid. The interaction between the converter and the grid may affect the stability of the grid-connected system. This paper mainly studies the control strategy of grid-connected converter under the condition of weak electric network, and analyzes the influence of impedance interaction between power grid and converter on the stability of grid-connected system. A phase locked loop (PLL) method suitable for grid-connected converters with weak electric grids is also selected. First, the stability criterion based on impedance is explained, which is used as the theoretical basis for analyzing the stability of grid-connected interactive systems. The output impedance of grid-connected converter using L and LCL filters is modeled respectively. Because the LCL filter will introduce extra resonance peak to the grid-connected converter system, it will make the grid-connected system unstable. In this paper, the passive damping method is used to suppress the LCL resonance peak and increase the damping to make the system stable. In this paper, the harmonic resonance between grid-connected converter and weak grid is analyzed quantitatively in frequency domain because of the interaction of impedance. Theoretical analysis shows that harmonic resonance is easy to occur near the frequency where the impedance amplitude is equal to the impedance of the converter. Compared with the L-filter converter, the LCL filter converter is more likely to produce harmonic resonance with the weak current network. The simulation in time domain verifies the correctness of the theoretical analysis. Secondly, the phase-locked loop method based on the second-order generalized integrator is selected, and the validity and accuracy of the phase-locked loop method under different power grid conditions are verified by simulation. It is shown that this method is suitable for the three-phase grid-connected converter system under the condition of weak current network in this paper. Finally, the experimental platform of the three-phase grid-connected converter is built, and the stability analysis results of the grid-connected converter system under the condition of weak grid are verified experimentally. The results of current waveform and harmonic analysis under different power network conditions with different filters are given, and the correctness of the theoretical analysis and simulation results in this paper is verified.
【學(xué)位授予單位】：北京交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TM46

【參考文獻(xiàn)】

相關(guān)期刊論文 前8條

1 胡為兵;李開成;;電力系統(tǒng)實(shí)時(shí)相位同步方法的研究和比較[J];電測(cè)與儀表;2007年08期

2 郭小強(qiáng);鄔偉揚(yáng);顧和榮;王立喬;趙清林;;并網(wǎng)逆變器LCL接口直接輸出電流控制建模及穩(wěn)定性分析[J];電工技術(shù)學(xué)報(bào);2010年03期

3 劉飛;查曉明;段善旭;;三相并網(wǎng)逆變器LCL濾波器的參數(shù)設(shè)計(jì)與研究[J];電工技術(shù)學(xué)報(bào);2010年03期

4 林征宇,吳建德,何湘寧;基于DSP帶同步鎖相的逆變器控制[J];電力電子技術(shù);2001年02期

5 雷一;趙爭鳴;袁立強(qiáng);魯思兆;;LCL濾波的光伏并網(wǎng)逆變器阻尼影響因素分析[J];電力系統(tǒng)自動(dòng)化;2012年21期

6 許德志;汪飛;阮毅;毛華龍;張巍;楊影;;多逆變器并網(wǎng)系統(tǒng)輸出阻抗建模與諧波交互[J];電機(jī)與控制學(xué)報(bào);2014年02期

7 王要強(qiáng);吳鳳江;孫力;孫奎;;阻尼損耗最小化的LCL濾波器參數(shù)優(yōu)化設(shè)計(jì)[J];中國電機(jī)工程學(xué)報(bào);2010年27期

8 陳新;張e，

本文編號(hào)：2095547