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  本文關(guān)鍵詞： 晶閘管 并聯(lián) 精確線性化 非線性 混沌　出處：《湘潭大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：晶閘管器件具有耐壓高、電流大等優(yōu)點,在靜止無功補(bǔ)償、高壓直流輸電和高壓變頻調(diào)速等應(yīng)用場合仍是主要采用的功率器件,且在很多場合需要采用晶閘管并聯(lián)技術(shù)�，F(xiàn)有晶閘管并聯(lián)技術(shù)主要以阻感保護(hù)、阻容保護(hù)等方法為主,能夠滿足晶閘管并聯(lián)的基本要求。然而,晶閘管是一個強(qiáng)的非線性元件,研究結(jié)果表明在不同驅(qū)動電壓、工作頻率和供電電壓下會產(chǎn)生分岔及混沌行為,并使得晶閘管出現(xiàn)“電流細(xì)絲”現(xiàn)象,這將導(dǎo)致晶閘管因局部過流而損壞。因此,如何使晶閘管并聯(lián)系統(tǒng)在局部和全局都保持良好的均流特性成為重要課題之一。本文以晶閘管器件為研究對象,建立非線性動力學(xué)模型,分析其分岔及混沌非線性行為,以期深入地探討晶閘管并聯(lián)系統(tǒng)非線性控制策略,為提高晶閘管并聯(lián)系統(tǒng)的安全性與可靠性奠定研究基礎(chǔ)。主要研究內(nèi)容可論述如下:(1)分析了晶閘管器件的內(nèi)部物理結(jié)構(gòu)和工作機(jī)理,基于半導(dǎo)體物理理論建立晶閘管非線性動力學(xué)模型,重點研究了漂移區(qū)的動力學(xué)行為,推導(dǎo)了其雙極擴(kuò)散動力學(xué)方程。(2)基于晶閘管非線性動力學(xué)模型,系統(tǒng)分析了晶閘管外部電學(xué)特性與其內(nèi)部物理量演化的相互聯(lián)系,并在此基礎(chǔ)上研究了晶閘管器件呈現(xiàn)的倍周期分岔及混沌等非線性現(xiàn)象。此外,探討了晶閘管非線性現(xiàn)象對其并聯(lián)電路工作特性的影響。研究結(jié)果表明,由于電路寄生參數(shù)和器件物理參數(shù)的差異,將會造成分岔或混沌行為而使得并聯(lián)電路中晶閘管觸發(fā)時刻的不同步,由此導(dǎo)致晶閘管間存在動態(tài)均流的問題,必然會影響到晶閘管的安全穩(wěn)定運(yùn)行。(3)為提高晶閘管并聯(lián)系統(tǒng)的穩(wěn)定性,本文基于狀態(tài)反饋精確線性化方法從新的角度來解決晶閘管并聯(lián)系統(tǒng)中存在的同步觸發(fā)問題。首先,建立了晶閘管并聯(lián)系統(tǒng)的非線性仿射模型,基于微分幾何理論驗證了該系統(tǒng)是否滿足精確線性化的前提條件,再通過非線性坐標(biāo)變換實現(xiàn)了晶閘管并聯(lián)系統(tǒng)狀態(tài)反饋精確線性化,并結(jié)合線性最優(yōu)控制理論確定了狀態(tài)反饋控制律,最后通過數(shù)值仿真證實了該控制方案的有效性,從而為晶閘管并聯(lián)系統(tǒng)的同步觸發(fā)控制提供了一種新思路。
[Abstract]:Thyristor devices have the advantages of high voltage resistance and high current. They are still the main power devices in static reactive power compensation, HVDC transmission and high voltage frequency conversion speed regulation and other applications. In many cases, the thyristor parallel technology is needed. The existing thyristor parallel technology mainly uses resistive protection, resistive and capacitive protection methods, which can meet the basic requirements of thyristor parallel connection. Thyristor is a strong nonlinear element. The research results show that bifurcation and chaos will occur under different driving voltage, working frequency and supply voltage, and the "current filaments" phenomenon will appear in the thyristor. This will lead to the damage of thyristor due to local overcurrent. Therefore, how to make the thyristor parallel system maintain good current-sharing characteristics both locally and globally has become one of the important topics. This paper takes thyristor devices as the research object. The nonlinear dynamic model is established to analyze the bifurcation and chaotic nonlinear behavior in order to discuss the nonlinear control strategy of thyristor parallel system. In order to improve the safety and reliability of thyristor parallel system, the main research contents can be described as follows: 1) the internal physical structure and working mechanism of thyristor devices are analyzed. Based on the semiconductor physics theory, the nonlinear dynamic model of thyristor is established. The dynamic behavior of drift region is studied, and its bipolar diffusion dynamic equation is derived. (2) based on the nonlinear dynamic model of thyristor. The relationship between the external electrical characteristics of thyristors and the evolution of their internal physical quantities is systematically analyzed, and the nonlinear phenomena such as periodic doubling bifurcation and chaos in thyristor devices are studied on this basis. The effect of thyristor nonlinearity on the performance of parallel circuit is discussed. The results show that the parasitic parameters of the circuit and the physical parameters of the device are different. It will cause bifurcation or chaos and make the thyristor trigger time in parallel circuit out of sync, which leads to the problem of dynamic current sharing between thyristors. In order to improve the stability of thyristor parallel system, it will affect the safe and stable operation of thyristor. In this paper, the synchronization trigger problem in thyristor parallel system is solved from a new angle based on the state feedback exact linearization method. Firstly, a nonlinear affine model of thyristor parallel system is established. Based on the differential geometry theory, it is verified that the system satisfies the precondition of accurate linearization, and the state feedback linearization of thyristor parallel system is realized by nonlinear coordinate transformation. Combined with the linear optimal control theory, the state feedback control law is determined. Finally, the effectiveness of the control scheme is verified by numerical simulation, which provides a new way for synchronous trigger control of thyristor parallel system.
【學(xué)位授予單位】：湘潭大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TN34

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相關(guān)期刊論文 前1條

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本文編號：1462121