本文關(guān)鍵詞：三相LCL型并網(wǎng)逆變器中電網(wǎng)電壓引起的諧波和不平衡電流抑制研究　出處：《華中科技大學(xué)》2014年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 可再生能源 分布式發(fā)電系統(tǒng) 三相LCL型并網(wǎng)逆變器 諧波電流 不平衡 電網(wǎng)電壓前饋 復(fù)矢量前置濾波器 弱電網(wǎng)

【摘要】：作為基于可再生能源的分布式發(fā)電系統(tǒng)(Renewable Energy based Distributed Power Generation System, RE-DPGS)與電網(wǎng)的能量變換接口,并網(wǎng)逆變器的作用十分重要。實(shí)際電網(wǎng)中含有背景諧波和不平衡分量,導(dǎo)致并網(wǎng)逆變器的并網(wǎng)電流中也產(chǎn)生諧波和不平衡分量,影響RE-DPGS的安全、穩(wěn)定和高質(zhì)量運(yùn)行。因此,并網(wǎng)電流的諧波和不平衡分量抑制具有重要意義。本文針對廣泛應(yīng)用的三相LCL型并網(wǎng)逆變器,研究電網(wǎng)電壓引起的并網(wǎng)電流諧波和不平衡分量的抑制方法。 本文研究內(nèi)容主要如下： 本文首先推導(dǎo)三相LCL型并網(wǎng)逆變器在靜止α-β坐標(biāo)系和同步旋轉(zhuǎn)d-q坐標(biāo)系下控制的開關(guān)平均模型。在此基礎(chǔ)上,分析電網(wǎng)電壓對并網(wǎng)電流的影響機(jī)理,指出電網(wǎng)電壓從并網(wǎng)電流擾動分量和指令值給定誤差兩方面對并網(wǎng)逆變器的并網(wǎng)電流產(chǎn)生影響,這為后續(xù)并網(wǎng)電流諧波及不平衡分量的抑制方法打下基礎(chǔ)。 為了抑制電網(wǎng)電壓引起的逆變器并網(wǎng)電流擾動分量,本文提出靜止α-β坐標(biāo)系、同步旋轉(zhuǎn)d-q坐標(biāo)系和混合坐標(biāo)系下控制的三相LCL型并網(wǎng)逆變器的電網(wǎng)電壓全前饋策略,并對三相LCL型并網(wǎng)逆變器電網(wǎng)電壓全前饋函數(shù)中三項(xiàng)(比例項(xiàng)、一次微分項(xiàng)和二次微分項(xiàng))的作用進(jìn)行分析,闡明電網(wǎng)電壓全前饋的物理意義。結(jié)合工程實(shí)際,分析LCL濾波器參數(shù)變化對電網(wǎng)電壓全前饋策略效果的影響,并將得到的三相LCL型并網(wǎng)逆變器電網(wǎng)電壓全前饋策略與三相L型并網(wǎng)逆變器電網(wǎng)電壓前饋策略對比,指出當(dāng)LCL型并網(wǎng)逆變器的輸出濾波電容Cf為零時(shí),LCL型并網(wǎng)逆變器的電網(wǎng)電壓全前饋函數(shù)轉(zhuǎn)化為L型逆變器的電網(wǎng)電壓前饋函數(shù)。搭建20kW三相LCL型并網(wǎng)逆變器實(shí)驗(yàn)平臺,通過實(shí)驗(yàn)驗(yàn)證理論分析的正確性和所提出的電網(wǎng)電壓全前饋策略的有效性。 為了抑制電網(wǎng)電壓引起的逆變器并網(wǎng)電流指令值給定誤差,本文采用復(fù)矢量濾波器概念,對并網(wǎng)逆變器中基于前置濾波器的同步鎖相系統(tǒng)進(jìn)行分析。根據(jù)前置濾波器的復(fù)矢量傳遞函數(shù)將其分為一階、二階和多模塊高階復(fù)矢量濾波器,并以一階復(fù)矢量濾波器為基礎(chǔ),推導(dǎo)二階和多模塊高階復(fù)矢量濾波器及其標(biāo)量傳遞函數(shù)實(shí)現(xiàn)形式,指出一階和二階復(fù)矢量濾波器是多模塊高階復(fù)矢量濾波器的一種特殊情況。在此基礎(chǔ)上,針對傳統(tǒng)二階復(fù)矢量濾波器動態(tài)性能的局限性,提出具有更好動態(tài)性能的通用二階復(fù)矢量前置濾波器,以實(shí)現(xiàn)突發(fā)的電網(wǎng)不對稱故障情況下電網(wǎng)電壓基波正序和負(fù)序分量的快速準(zhǔn)確檢測。為了更好地抑制電網(wǎng)電壓諧波分量,本文還提出一種三階復(fù)矢量濾波器。最后,通過仿真和實(shí)驗(yàn)結(jié)果,驗(yàn)證上述理論分析的正確性和所提出的兩種復(fù)矢量前置濾波器的有效性。 針對電網(wǎng)內(nèi)阻抗較大的弱電網(wǎng)情況,負(fù)荷和發(fā)電單元的接入對電網(wǎng)影響相對明顯,本文以靜止α-β坐標(biāo)系下控制的三相LCL型并網(wǎng)逆變器為例,對并網(wǎng)逆變器輸出阻抗特性和電網(wǎng)電壓全前饋策略對并網(wǎng)逆變器輸出阻抗的影響進(jìn)行分析。在此基礎(chǔ)上,根據(jù)基于阻抗的并網(wǎng)逆變器穩(wěn)定性判據(jù),對加入電網(wǎng)電壓全前饋前后的并網(wǎng)逆變器的穩(wěn)定性問題進(jìn)行分析,指出加入電網(wǎng)電壓全前饋后,并網(wǎng)逆變器的輸出阻抗負(fù)相移增大,在弱電網(wǎng)下可能無法穩(wěn)定工作。為此,提出電網(wǎng)電壓特定次分量前饋策略,該策略在有效抑制并網(wǎng)電流諧波和不平衡分量的同時(shí),能夠保證弱電網(wǎng)下逆變器的穩(wěn)定工作。
[Abstract]:As a renewable energy based distributed power generation system ( RE - DPGS ) and the energy conversion interface of the power grid , the function of the grid - connected inverter is very important . The harmonic and unbalanced components are also generated in the grid - connected current of the grid - connected inverter , which affects the safety , stability and high - quality operation of the RE - DPGS . The main contents of this paper are as follows : On this basis , the influence mechanism of grid voltage on grid current is analyzed . It is pointed out that the grid voltage has an influence on grid current of grid - connected inverter in terms of grid current disturbance component and instruction value given error , which lays the foundation for the suppression of grid current harmonic and unbalanced component . In order to suppress the disturbance component of grid voltage caused by grid voltage , this paper proposes a full feed - forward strategy for grid voltage of three - phase LFC connected inverter controlled by stationary 偽 - 尾 coordinate system , synchronous rotating d - q coordinate system and mixed coordinate system . Based on the complex vector transfer function of the pre - filter , it is divided into one - order , second - order and multi - module high - order complex vector filters . Based on the complex vector transfer function of the pre - filter , a general - purpose second order complex vector filter with better dynamic performance is proposed . In order to suppress the harmonic components of the power grid voltage , a third order complex vector filter is proposed . Finally , the correctness of the above theoretical analysis and the effectiveness of the two kinds of complex vector prefilters are verified by simulation and experimental results . On the basis of the impedance - based grid - connected inverter stability criterion , this paper analyzes the stability of grid - connected inverter before and after the addition of grid voltage , and points out that the output impedance of grid - connected inverter is increased and the output impedance of grid - connected inverter is increased .

【學(xué)位授予單位】：華中科技大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：TM464

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本文編號：1439158