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  本文選題：模塊化多電平逆變器 + 電容電壓平衡控制��； 參考：《中國礦業(yè)大學(xué)》2014年碩士論文

【摘要】：近年來，電力電子技術(shù)在高壓大功率領(lǐng)域的應(yīng)用日益廣泛，在高壓功率開關(guān)器件技術(shù)沒有本質(zhì)突破的前提下，利用中壓功率器件的多電平逆變器是解決高壓大功率變換的最好選擇。同時，隨著新能源技術(shù)及輕型直流輸電系統(tǒng)的發(fā)展，一種新型電壓源型多電平逆變器拓撲結(jié)構(gòu)：模塊化多電平逆變器（ModularMultilevel Converter, MMC）因其具有模塊化程度高、易于拓展，輸出電壓諧波特性好，等效開關(guān)頻率高等優(yōu)點而受到日益廣泛的關(guān)注。目前，國內(nèi)外針對MMC的學(xué)術(shù)研究相對較少，亟待對其進行深入研究。 本文詳細分析了模塊化多電平逆變器的拓撲及其工作原理，建立了MMC的數(shù)學(xué)模型，為逆變器的控制策略分析奠定了基礎(chǔ)。在模塊化多電平逆變器中，直流母線提供的電流必須通過子模塊的懸浮電容輸出至負載，因此電容電壓會出現(xiàn)一定的波動。大量懸浮電容的電壓平衡控制是保證系統(tǒng)穩(wěn)定可靠工作的前提條件，，本文從逆變器橋臂的功率脈動與能量脈動的角度對影響子模塊電容電壓波動的因素進行了深入分析，為本文電壓平衡控制策略的提出提供了理論依據(jù)。 為解決傳統(tǒng)載波層疊PWM技術(shù)中MMC子模塊開關(guān)頻率不一致的問題，本文將循環(huán)虛擬映射的概念應(yīng)用于模塊化多電平逆變器，在載波層疊PWM調(diào)制技術(shù)中建立虛擬子模塊和實際子模塊之間的無差別循環(huán)映射關(guān)系；在此基礎(chǔ)上，本文提出了基于載波層疊PWM技術(shù)的選擇性循環(huán)虛擬映射（Selective Virtual LoopMapping, SVLM）電壓平衡控制方法，該方法不需要將子模塊按照電壓值大小排序，使其適用于模塊化多電平逆變器子模塊數(shù)目眾多的場合，也不需要向調(diào)制波上疊加額外的控制分量，諧波性能好，并且該方法具有很強的動態(tài)調(diào)節(jié)能力。仿真結(jié)果顯示，該方法能夠很好地平衡能量在MMC的子模塊電容之間的分配，有效地平衡電容電壓及抑制環(huán)流，整個系統(tǒng)具有良好的動靜態(tài)特性。 在五電平模塊化多電平變換器的實驗平臺上對本文提出的電壓平衡控制方法進行了實驗驗證，為MMC的推廣應(yīng)用提供了實驗依據(jù)。
[Abstract]:In recent years, power electronics technology has been widely used in the field of high voltage and high power. Multilevel inverter with medium-voltage power device is the best choice to solve high-voltage and high-power conversion. At the same time, with the development of new energy technology and light DC transmission system, a new type of voltage source multilevel inverter topology: modular multilevel inverter (MMCT) is easy to expand because of its high modularization degree. More and more attention has been paid to the advantages of good harmonic characteristics of output voltage and high equivalent switching frequency. At present, there are relatively few academic researches on MMC at home and abroad. In this paper, the topology and working principle of the modular multilevel inverter are analyzed in detail, and the mathematical model of MMC is established, which lays a foundation for the analysis of the control strategy of the inverter. In the modularized multilevel inverter, the current provided by DC bus must be output to the load through the suspension capacitance of the submodule, so the capacitance voltage will fluctuate to a certain extent. Voltage balance control of a large number of suspended capacitors is a prerequisite to ensure the stability and reliability of the system. In this paper, the factors affecting the voltage fluctuation of submodules are deeply analyzed from the angle of power pulsation and energy pulsation of the bridge arm of the inverter. It provides a theoretical basis for the voltage balance control strategy in this paper. In order to solve the problem of inconsistent switching frequency of MMC submodule in traditional carrier stacked PWM technology, the concept of cyclic virtual mapping is applied to modularized multilevel inverter in this paper. In the carrier stacked PWM modulation technology, the non-differential cyclic mapping relationship between the virtual submodule and the actual sub-module is established, and on this basis, In this paper, a selective Virtual Loop Mapping (SVLM) voltage balance control method based on carrier stacked PWM technology is proposed. The method is suitable for the multi-level inverter with a large number of modules, and it does not need to add additional control components to the modulation wave. The harmonic performance is good, and the method has a strong dynamic adjustment ability. The simulation results show that this method can balance the energy distribution among the submodule capacitors of MMC effectively balance the capacitance voltage and suppress the circulation. The whole system has good dynamic and static characteristics. The voltage balance control method proposed in this paper is experimentally verified on the experimental platform of the five-level modular multilevel converter, which provides the experimental basis for the popularization and application of MMC.
【學(xué)位授予單位】：中國礦業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TM464

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本文編號：1814706