本文選題：多機(jī)逆變器并聯(lián)系統(tǒng) + 諧振特性��； 參考：《華北電力大學(xué)》2017年碩士論文

【摘要】：近年來,我國分布式光伏呈現(xiàn)出連片開發(fā),集群并網(wǎng)的特點。光伏集群系統(tǒng)中存在大量的LCL濾波器,與配網(wǎng)阻抗構(gòu)成復(fù)雜的高階電網(wǎng)絡(luò),使光伏集群系統(tǒng)存在多個的固有諧振點。當(dāng)分布式發(fā)電集群入網(wǎng)系統(tǒng)電壓電流諧波頻率與系統(tǒng)固有諧振點頻率相匹配時,將發(fā)生諧振。目前已有的分布式光伏并網(wǎng)工程中,已出現(xiàn)了多起逆變器并聯(lián)運行產(chǎn)生諧振導(dǎo)致并網(wǎng)失敗的案例。因此,研究弱電網(wǎng)條件下,多機(jī)逆變器并聯(lián)系統(tǒng)的諧振特性及其抑制策略對實現(xiàn)新能源系統(tǒng)安全穩(wěn)定運行具有重要的意義。本文以多機(jī)逆變器并聯(lián)系統(tǒng)為研究對象,分析系統(tǒng)的諧振特性。首先研究并聯(lián)LCL系統(tǒng)的多輸入多輸出傳遞函數(shù),并在此基礎(chǔ)上,建立了多機(jī)逆變器并聯(lián)系統(tǒng)的傳遞函數(shù),利用此模型分析多機(jī)逆變器之間的交互影響,得到并聯(lián)逆變器數(shù)量、電網(wǎng)阻抗和系統(tǒng)組成比例對系統(tǒng)諧振特性的影響。針對LCL型逆變器的并網(wǎng)諧振問題,開展逆變器自身的無源阻尼和有源阻尼諧振抑制方法的研究。對無源阻尼方法和有源阻尼方法的機(jī)理進(jìn)行研究,并分析電網(wǎng)阻抗對無源阻尼以及有源阻尼方法的影響。最后,提出一種基于陷波控制的逆變器自身諧振抑制方法。針對光伏集群全局諧振問題,本文提出集中式的諧振抑制方法。根據(jù)諧振抑制的不同原理,分別提出無源型投切阻抗式諧振抑制技術(shù)和有源型虛擬阻尼式諧振抑制方法,這兩種方法都為在并網(wǎng)點處并聯(lián)一臺諧振抑制裝置實現(xiàn)對分布式光伏集群的諧振抑制。最后,通過仿真驗證兩種方法的正確性。
[Abstract]:In recent years, distributed photovoltaic in China presents the characteristics of continuous development and cluster grid-connected.There are a large number of LCL filters in photovoltaic cluster system, which form a complex high-order electric network with impedance of distribution network, which makes photovoltaic cluster system have multiple inherent resonance points.When the harmonic frequency of voltage and current is matched with the frequency of the inherent resonance point of the system, the resonance will occur.In the existing distributed photovoltaic grid-connected projects, there have been many cases of inverter parallel operation resulting in resonance resulting in grid connection failure.Therefore, it is of great significance to study the resonance characteristics and its suppression strategy of multi-machine inverter parallel system under the condition of weak current network to realize the safe and stable operation of the new energy system.In this paper, the resonant characteristics of multi-machine inverter parallel system are analyzed.Firstly, the transfer function of parallel LCL system is studied. Based on this, the transfer function of parallel inverter is established. The interaction between inverter and inverter is analyzed by using this model, and the number of parallel inverters is obtained.The influence of power system impedance and system composition ratio on the resonance characteristics of the system.Aiming at the grid-connected resonant problem of LCL inverter, the passive damping and active damping resonant suppression methods of the inverter are studied.Finally, a notch control based resonant suppression method is proposed.Aiming at the global resonance problem of photovoltaic cluster, a centralized resonant suppression method is proposed in this paper.According to different principles of resonant suppression, passive switching impedance resonant suppression and active virtual damping resonant suppression are proposed, respectively.Both of these two methods are designed to realize the resonance suppression of distributed photovoltaic cluster by paralleling a resonance suppressor at the parallel node.Finally, the correctness of the two methods is verified by simulation.
【學(xué)位授予單位】：華北電力大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TM464;TM615

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本文編號：1754742