本文選題：微電網(wǎng) + 電力電子變壓器　； 參考：《杭州電子科技大學》2014年碩士論文

【摘要】：在傳統(tǒng)化石能源日趨緊張以及節(jié)能減排的全球大背景下，，分布式發(fā)電技術飛速發(fā)展，整合了分布式發(fā)電、電力電子、電力系統(tǒng)控制技術的微型電網(wǎng)技術受到人們越來越多的重視。為實現(xiàn)微網(wǎng)與大電網(wǎng)之間的有效互補，微網(wǎng)并網(wǎng)技術值得深入探究。傳統(tǒng)微網(wǎng)并網(wǎng)方式存在并網(wǎng)速度慢、沖擊大、供電可靠性低、潮流無法控制等問題，另外由于兩個電網(wǎng)之間不存在有效的隔離措施，任何一側(cè)電網(wǎng)發(fā)生故障電流、諧波污染等問題都將對另一側(cè)電網(wǎng)產(chǎn)生影響，電能質(zhì)量得不到有效保證。所以有必要采用一種新的微網(wǎng)并網(wǎng)方式，來提高微網(wǎng)與大電網(wǎng)并網(wǎng)的可靠性和靈活性。 本文對微電網(wǎng)并網(wǎng)方式、關鍵控制技術進行深入剖析的基礎上，設計了一種基于電力電子變壓器的新型微網(wǎng)并網(wǎng)裝置結(jié)構(gòu)。該裝置由電力電子變壓器及儲能系統(tǒng)兩部分組成，取代了傳統(tǒng)并網(wǎng)所需的常規(guī)電力變壓器和斷路器，不僅能夠快速、準確地變換電壓，實現(xiàn)電路的接通與開斷，還可實現(xiàn)微網(wǎng)與配電網(wǎng)的異步運行。 在分析并網(wǎng)裝置結(jié)構(gòu)的基礎上，提出了微網(wǎng)DG與并網(wǎng)裝置的協(xié)調(diào)控制策略：并網(wǎng)裝置中PET輸出級VSC作為主控單元采用V/f控制，微網(wǎng)DG作為從控制單元，采用PQ控制或者定直流電壓控制；利用PSCAD/EMTDC仿真工具對基于電力電子變壓器并網(wǎng)裝置的微網(wǎng)模型在聯(lián)網(wǎng)模式、孤島模式以及聯(lián)網(wǎng)與孤島模式切換下進行了仿真分析，仿真結(jié)果表明并網(wǎng)裝置在聯(lián)網(wǎng)和孤島運行時均能保持微網(wǎng)電壓和頻率穩(wěn)定，同時具有無功補償作用；在聯(lián)網(wǎng)與孤島運行模式切換時無需對電力電子變壓器輸出級及微網(wǎng)內(nèi)其他DG的控制策略進行改變，且變換速度快，沖擊小。 討論了微網(wǎng)接入對配電網(wǎng)在潮流、網(wǎng)損、電能質(zhì)量、市場模式等方面的影響，明確了電網(wǎng)友好型微網(wǎng)的定義，認為電網(wǎng)友好型微網(wǎng)的核心問題是盡可能地維持微網(wǎng)與大電網(wǎng)之間功率交換的恒定。在此基礎上，提出了基于并網(wǎng)裝置的電網(wǎng)友好型微網(wǎng)的控制策略：并網(wǎng)裝置中電力電子變壓器輸出級采用PQ控制策略，功率不易調(diào)整的微源采用PQ控制或定直流電壓控制策略，功率易于調(diào)整的微源及可控負荷均采用下垂控制策略。利用PSCAD/EMTDC仿真工具對電網(wǎng)友好模式下的微網(wǎng)進行仿真分析，仿真結(jié)果表明當微網(wǎng)內(nèi)不可控負荷或者微源突變時，微網(wǎng)內(nèi)部功率易于調(diào)整的微源及可控負荷均能對突變的功率進行合理分配，保證微網(wǎng)內(nèi)功率平衡，維持并網(wǎng)點功率交換的恒定；當并網(wǎng)點功率交換發(fā)生突變時，功率易于調(diào)整的微源及可控負荷同樣能夠合理分配功率，維持微網(wǎng)內(nèi)部功率平衡，實現(xiàn)微網(wǎng)的穩(wěn)定運行。
[Abstract]:Under the background of the increasing tension of traditional fossil energy and the global background of energy saving and emission reduction, distributed power generation technology has developed rapidly, integrating distributed generation, power electronics, People pay more and more attention to the microgrid technology of power system control technology. In order to realize the effective complementation between microgrid and large power grid, microgrid grid-connected technology is worth exploring deeply. There are some problems in the traditional micro-grid connection, such as slow speed, big impact, low reliability of power supply, uncontrollable power flow, etc. In addition, because there is no effective isolation between the two power grids, fault currents occur on either side of the grid. Harmonic pollution and other problems will have an impact on the other side of the grid, power quality can not be effectively guaranteed. So it is necessary to adopt a new mode of microgrid connection to improve the reliability and flexibility of microgrid and large power grid. Based on the deep analysis of microgrid grid-connected mode and key control technology, a new type of micro-grid grid-connected device based on power electronic transformer is designed in this paper. The device consists of two parts, power electronic transformer and energy storage system. It replaces the conventional power transformer and circuit breaker needed for traditional grid-connection. It can not only quickly and accurately change the voltage, but also realize the circuit switching on and off. The asynchronous operation of microgrid and distribution network can also be realized. On the basis of analyzing the structure of the grid-connected device, the coordinated control strategy between the microgrid DG and the grid-connected device is put forward. In the grid-connected device, the PET output stage VSC is used as the main control unit, and the microgrid DG is used as the slave control unit. Using PQ control or constant DC voltage control, the microgrid model based on power electronic transformer grid-connected device is simulated and analyzed under the network mode, islanding mode, and switching between networked and islanding modes by using PSCAD/EMTDC simulation tool. The simulation results show that the grid-connected device can keep the voltage and frequency of the microgrid stable and has the function of reactive power compensation. There is no need to change the control strategy of the power electronic transformer output stage and other DG in the microgrid when switching the operation mode between the interconnection and the isolated island, and the conversion speed is fast and the impact is small. The influence of microgrid access on power flow, network loss, power quality, market mode and so on is discussed, and the definition of grid-friendly microgrid is defined. It is considered that the core problem of grid-friendly microgrid is to keep the power exchange between microgrid and large grid as constant as possible. On this basis, the control strategy of grid-friendly microgrid based on grid-connected device is put forward. In grid-connected device, PQ control strategy is used for output stage of power electronic transformer, and PQ control strategy or constant DC voltage control strategy is used for micro-source which power is not easy to adjust. The droop control strategy is used for microsource and controllable load which can be adjusted easily. The simulation analysis of microgrid in grid-friendly mode is carried out by using PSCAD/EMTDC simulation tool. The simulation results show that when the load in the microgrid is uncontrollable or the microsource changes, The microsource and controllable load, which are easy to adjust the power inside the microgrid, can distribute the power of the mutation reasonably, ensure the power balance in the microgrid, and maintain the constant power exchange of the parallel network. The microsource and the controllable load, which are easy to adjust the power, can distribute the power reasonably, maintain the balance of the power inside the microgrid, and realize the steady operation of the microgrid.
【學位授予單位】：杭州電子科技大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TM41

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本文編號：1831934