基于單相多級聯(lián)逆變器的特性研究
發(fā)布時間：2018-11-17 07:02
【摘要】：隨著電力電子交流技術(shù)的不斷發(fā)展,各種先進(jìn)的控制技術(shù)層出不窮。由于受電力電子器件電壓容量的限制,傳統(tǒng)的兩電平變頻器通常采用“高-低-高”方式經(jīng)變壓器降壓和升壓來獲得高壓大功率,或采用多個小容量逆變單元經(jīng)多繞組變壓器多重化來實現(xiàn),這使得系統(tǒng)效率和可靠性下降。因而,人們希望實現(xiàn)直接的高壓逆變技術(shù),而多電平功率變換技術(shù)因其在高壓大功率應(yīng)用場合的廣闊前景,就成為了電力電子領(lǐng)域的研究熱點。圍繞多電平變換器,新型電路拓?fù)浼跋嚓P(guān)調(diào)制策略層出不窮,級聯(lián)型多電平逆變器由于其具有開關(guān)應(yīng)力小,輸出波形優(yōu),易于封裝和擴(kuò)展等優(yōu)點,越來越多地被應(yīng)用于中高壓頻率調(diào)速、柔性交流輸電和高壓直流輸電等高壓大功率場合。本文首先介紹了多電平逆變器的產(chǎn)生背景及其發(fā)展現(xiàn)狀,對它的幾種拓?fù)浣Y(jié)構(gòu)進(jìn)行了詳細(xì)介紹,并對各自的特點和適用場合進(jìn)行了比較分析,從而引出H橋級聯(lián)型多電平逆變器的優(yōu)越性能和廣闊應(yīng)用前景,接下來,對H橋級聯(lián)逆變器的結(jié)構(gòu)和工作機(jī)理進(jìn)行了重點介紹,并在此基礎(chǔ)上,引出了級聯(lián)逆變器的PWM調(diào)制方法,在對各種方法的分析比較下,引出了載波相移正弦脈寬調(diào)制(C P S-S P WM)策略,并對它進(jìn)行了深入剖析研究。另一方面,在載波相移控制下的級聯(lián)逆變器在調(diào)制過程中,是通過載波對正弦信號進(jìn)行調(diào)制的,這會產(chǎn)生和載波有關(guān)的諧波分量,而這些輸出諧波頻率和幅值已成為衡量PWM多級聯(lián)逆變電路的重要指標(biāo)之一,因此也必須對CPS-SPWM調(diào)制策略的諧波進(jìn)行準(zhǔn)確分析并給予有效地抑制。本文最后也重點研究了單相級聯(lián)型多電平逆變器在CPS-SPWM調(diào)制下的的輸出特性,重點是諧波的變化規(guī)律:隨著H橋單元個數(shù)的增加,輸出波形會越來越接近正弦波,諧波含量也會越小;同時隨著調(diào)制度和載波頻率等參數(shù)的變化,輸出波形諧波情況也發(fā)生相應(yīng)變化。最終,應(yīng)用MATLAB進(jìn)行了仿真分析,并且結(jié)合實際電路完成了實驗分析,驗證了逆變器的輸出規(guī)律,達(dá)到了預(yù)期效果。
[Abstract]:With the continuous development of power electronic AC technology, various advanced control technologies emerge in endlessly. Because of the limitation of the voltage capacity of the power electronic devices, the traditional two-level inverter usually adopts the "high-low-high" mode to obtain high voltage and high power through the transformer voltage reduction and boost voltage. Or multiple small capacity inverters are realized by multi-winding transformers, which reduces the efficiency and reliability of the system. Therefore, people want to realize direct high-voltage inverter technology, and multilevel power conversion technology has become a research hotspot in the field of power electronics because of its broad prospect in high-voltage and high-power applications. Around multilevel converters, new circuit topologies and related modulation strategies emerge endlessly. Cascaded multilevel inverters have the advantages of low switching stress, excellent output waveform, easy encapsulation and expansion, etc. More and more applications are used in high voltage and high power applications, such as medium and high voltage frequency regulation, flexible AC transmission and high voltage direct current transmission. In this paper, the background and development of multilevel inverter are introduced, and several kinds of topology are introduced in detail, and their characteristics and applications are compared and analyzed. Thus, the superior performance and broad application prospect of H-bridge cascaded multilevel inverter are introduced. Then, the structure and working mechanism of H-bridge cascaded inverter are introduced emphatically, and on this basis, The PWM modulation method of cascaded inverter is introduced. Under the analysis and comparison of various methods, the (C P S-S P WM) strategy of carrier phase shift sinusoidal pulse width modulation is introduced, and it is deeply analyzed and studied. On the other hand, in the process of modulation, the cascaded inverter controlled by carrier phase shift modulates the sinusoidal signal through the carrier, which will produce the harmonics associated with the carrier. These output harmonic frequencies and amplitudes have become one of the important indexes to measure PWM multi-cascade inverter circuits. Therefore, the harmonic of CPS-SPWM modulation strategy must be accurately analyzed and effectively suppressed. In the end of this paper, the output characteristics of single-phase cascaded multilevel inverter under CPS-SPWM modulation are also studied. The emphasis is on the law of harmonic variation: with the increase of the number of H-bridge units, the output waveform will be more and more close to sine wave. The harmonic content will be smaller; At the same time, with the change of modulation and carrier frequency, the harmonic of output waveform also changes. Finally, the simulation analysis is carried out by using MATLAB, and the experimental analysis is completed in combination with the actual circuit. The output rule of the inverter is verified and the expected effect is achieved.
【學(xué)位授予單位】：西安電子科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TM464
本文編號：2336887
[Abstract]:With the continuous development of power electronic AC technology, various advanced control technologies emerge in endlessly. Because of the limitation of the voltage capacity of the power electronic devices, the traditional two-level inverter usually adopts the "high-low-high" mode to obtain high voltage and high power through the transformer voltage reduction and boost voltage. Or multiple small capacity inverters are realized by multi-winding transformers, which reduces the efficiency and reliability of the system. Therefore, people want to realize direct high-voltage inverter technology, and multilevel power conversion technology has become a research hotspot in the field of power electronics because of its broad prospect in high-voltage and high-power applications. Around multilevel converters, new circuit topologies and related modulation strategies emerge endlessly. Cascaded multilevel inverters have the advantages of low switching stress, excellent output waveform, easy encapsulation and expansion, etc. More and more applications are used in high voltage and high power applications, such as medium and high voltage frequency regulation, flexible AC transmission and high voltage direct current transmission. In this paper, the background and development of multilevel inverter are introduced, and several kinds of topology are introduced in detail, and their characteristics and applications are compared and analyzed. Thus, the superior performance and broad application prospect of H-bridge cascaded multilevel inverter are introduced. Then, the structure and working mechanism of H-bridge cascaded inverter are introduced emphatically, and on this basis, The PWM modulation method of cascaded inverter is introduced. Under the analysis and comparison of various methods, the (C P S-S P WM) strategy of carrier phase shift sinusoidal pulse width modulation is introduced, and it is deeply analyzed and studied. On the other hand, in the process of modulation, the cascaded inverter controlled by carrier phase shift modulates the sinusoidal signal through the carrier, which will produce the harmonics associated with the carrier. These output harmonic frequencies and amplitudes have become one of the important indexes to measure PWM multi-cascade inverter circuits. Therefore, the harmonic of CPS-SPWM modulation strategy must be accurately analyzed and effectively suppressed. In the end of this paper, the output characteristics of single-phase cascaded multilevel inverter under CPS-SPWM modulation are also studied. The emphasis is on the law of harmonic variation: with the increase of the number of H-bridge units, the output waveform will be more and more close to sine wave. The harmonic content will be smaller; At the same time, with the change of modulation and carrier frequency, the harmonic of output waveform also changes. Finally, the simulation analysis is carried out by using MATLAB, and the experimental analysis is completed in combination with the actual circuit. The output rule of the inverter is verified and the expected effect is achieved.
【學(xué)位授予單位】：西安電子科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TM464
【參考文獻(xiàn)】
相關(guān)期刊論文 前1條
1 周京華;吳理心;章小衛(wèi);李正熙;;多電平逆變器多載波調(diào)制策略的諧波分析[J];電機(jī)與控制學(xué)報;2011年05期
相關(guān)碩士學(xué)位論文 前1條
1 吳智超;混合多電平逆變器調(diào)制方法及輸出波形解析[D];華中科技大學(xué);2005年
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