本文選題：光伏并網(wǎng)逆變器　切入點：單位功率因數(shù)　出處：《中國礦業(yè)大學》2014年碩士論文

【摘要】：光伏并網(wǎng)發(fā)電系統(tǒng)主要由光伏陣列、并網(wǎng)逆變器和電網(wǎng)組成，三者都有可能發(fā)生故障，其中的并網(wǎng)逆變器單個開關(guān)管開路故障診斷與孤島檢測則是本文要進行深入研究的內(nèi)容。 并網(wǎng)逆變器能否可靠運行影響到其本身與電網(wǎng)的安全。并網(wǎng)逆變器主電路是由若干開關(guān)器件組合而成，而開關(guān)器件存在短路和開路故障。本文對單管開路故障特征量進行分析并根據(jù)光伏并網(wǎng)逆變器特點，給出一種三相光伏并網(wǎng)逆變器開關(guān)器件開路故障診斷方法。逆變器開關(guān)器件發(fā)生開路故障時電網(wǎng)中性點與直流側(cè)負極之間的電壓與正常工作時的電壓不同，將該電壓作為特征量。結(jié)合光伏并網(wǎng)逆變器單位功率因數(shù)并網(wǎng)特點，以電網(wǎng)電壓矢量角度為參考，對開路器件進行診斷。仿真和硬件實驗結(jié)果表明，該方法可以在一個電流周期內(nèi)準確定位開路故障器件。 孤島效應是所有分布式發(fā)電系統(tǒng)都要面臨的一個問題，孤島效應發(fā)生時，可能會給電網(wǎng)設(shè)備和人員帶來不利影響。本文介紹了常用的被動式和主動式孤島檢測方法的原理。采用P×Q坐標系對被動式孤島檢測算法的檢測盲區(qū)進行分析。針對P×Q坐標系的不足，采用Qf0×Cnorm坐標系對基于頻率的孤島檢測算法的檢測盲區(qū)進行分析。 針對孤島檢測算法中的主動頻率偏移法進行深入研究，詳細給出單相與三相主動頻率偏移法的實現(xiàn)過程。由于傳統(tǒng)的主動頻率偏移法會造成逆變器輸出電能質(zhì)量惡化，本文給出一種變反饋系數(shù)主動頻率偏移法。在電網(wǎng)頻率波動小的時候，采用小反饋系數(shù)；在電網(wǎng)頻率波動大的時候，采用大反饋系數(shù)。仿真和硬件實驗結(jié)果證明該方法在逆變器正常并網(wǎng)時對輸出電流的影響較小，當孤島效應發(fā)生時檢測能力比較突出，在孤島檢測的時間上也符合國家相關(guān)標準的規(guī)定。
[Abstract]:The photovoltaic grid-connected generation system is mainly composed of photovoltaic array, grid-connected inverter and power grid, all of which are likely to have faults. The open circuit fault diagnosis and islanding detection of grid-connected inverter are the contents of this paper.Whether the grid-connected inverter can run reliably will affect the security of itself and the power grid.The main circuit of grid-connected inverter is composed of several switching devices, which have short circuit and open circuit faults.According to the characteristics of photovoltaic grid-connected inverter, an open-circuit fault diagnosis method for switching devices of three-phase photovoltaic grid-connected inverter is presented in this paper.The voltage between the neutral point and the negative electrode of DC side is different from the voltage in normal operation when the switching device of inverter occurs open circuit fault, and this voltage is regarded as the characteristic value.Combined with the characteristics of grid-connected photovoltaic inverter with unit power factor, the open circuit device is diagnosed based on the voltage vector angle of the grid.Simulation and hardware experiments show that this method can accurately locate the open circuit fault devices in a current cycle.Islanding effect is a problem that all distributed generation systems have to face. When the islanding effect occurs, it may bring adverse effects to power grid equipment and personnel.This paper introduces the principle of passive and active island detection methods.The blind spot of passive isolated island detection algorithm is analyzed in P 脳 Q coordinate system.Aiming at the deficiency of P 脳 Q coordinate system, Qf0 脳 Cnorm coordinate system is used to analyze the blind spot detection of isolated island detection algorithm based on frequency.The active frequency migration method in islanding detection algorithm is studied in detail, and the realization process of single-phase and three-phase active frequency migration method is given in detail.Since the traditional active frequency offset method will cause the deterioration of the output power quality of the inverter, a variable feedback coefficient active frequency offset method is presented in this paper.The small feedback coefficient is used when the frequency fluctuation is small, and the large feedback coefficient is used when the frequency fluctuation is large.The results of simulation and hardware experiments show that the method has little effect on the output current when the inverter is grid-connected normally, and the detection ability is more prominent when the islanding effect occurs, and the detection time of the islanding detection is in accordance with the relevant national standards.
【學位授予單位】：中國礦業(yè)大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TM464

【參考文獻】

相關(guān)期刊論文 前10條

1 王磊;杜永紅;趙雷廷;吳佐民;劉志剛;;基于標幺化均值的大功率PWM整流器故障診斷[J];北京交通大學學報;2010年05期

2 劉芙蓉;康勇;段善旭;王輝;王志峰;;一種有效的孤島檢測盲區(qū)描述方法[J];電工技術(shù)學報;2007年10期

3 劉芙蓉;王輝;康勇;段善旭;;滑模頻率偏移法的孤島檢測盲區(qū)分析[J];電工技術(shù)學報;2009年02期

4 王磊;趙雷霆;張鋼;吳佐民;劉志剛;;電壓型PWM整流器的開關(guān)器件斷路故障特征[J];電工技術(shù)學報;2010年07期

5 安群濤;孫力;孫立志;趙克;;三相逆變器開關(guān)管故障診斷方法研究進展[J];電工技術(shù)學報;2011年04期

6 林明耀;顧娟;單竹杰;張怡然;;一種實用的組合式光伏并網(wǎng)系統(tǒng)孤島效應檢測方法[J];電力系統(tǒng)自動化;2009年23期

7 趙杰;張艷霞;宣文博;徐陸宇;;分布式電源中逆變器的故障特征和保護方案[J];電力系統(tǒng)自動化;2012年01期

8 孫強;段凱;;多機并網(wǎng)發(fā)電系統(tǒng)孤島效應的檢測方法[J];電力系統(tǒng)及其自動化學報;2012年05期

9 程啟明;王映斐;程尹曼;汪明媚;;分布式發(fā)電并網(wǎng)系統(tǒng)中孤島檢測方法的綜述研究[J];電力系統(tǒng)保護與控制;2011年06期

10 羅如意;林曄;;世界光伏發(fā)電產(chǎn)業(yè)的發(fā)展與展望[J];能源技術(shù);2009年05期

，

本文編號：1702715