【摘要】：并網(wǎng)逆變器廣泛應(yīng)用于光伏、風(fēng)力等可再生能源發(fā)電領(lǐng)域,作為分布式電源和電網(wǎng)的接口,其諧波抑制能力和進(jìn)網(wǎng)電流波形質(zhì)量是重要的性能指標(biāo)。本文主要研究了單相LCL型并網(wǎng)逆變器的并網(wǎng)電流控制策略,基于DSP和PV-IPM設(shè)計了3kW組串型并網(wǎng)逆變器,并完成了相關(guān)仿真和實驗驗證。 本文選用兩級式并網(wǎng)逆變器系統(tǒng)結(jié)構(gòu),前級DC/DC主要用于滿足最大功率點跟蹤和直流電壓輸入范圍的要求,DC/AC級則進(jìn)行逆變和并網(wǎng)的控制。首先研究了常見的DC/DC變換器、DC/AC變換器的拓?fù)潆娐?分析每種拓?fù)涞膬?yōu)缺點及應(yīng)用場合。進(jìn)一步研究了Boost電路實現(xiàn)MPPT的調(diào)制原理,雙極性、單極性、單極性倍頻式SPWM的調(diào)制特點和諧波特性。 LCL型濾波器在高頻段以-60dB/十倍頻衰減,比純電感濾波器具有更好的高次諧波衰減特性,但其控制模型為三階系統(tǒng),在諧振頻率處存在很高的諧振峰,這往往會引起電流波形畸變,因此需要采用適當(dāng)?shù)目刂撇呗蕴岣呦到y(tǒng)阻尼,增強控制系統(tǒng)穩(wěn)定性。傳統(tǒng)的無源阻尼方案是在濾波器中串聯(lián)或并聯(lián)電阻,但相應(yīng)的阻尼損耗以及高頻諧波抑制能力的削弱并不令人滿意,典型的有源阻尼技術(shù)有分裂電容法,電容電流內(nèi)環(huán)反饋,無差拍控制等。本文圍繞LCL型并網(wǎng)濾波器,對其參數(shù)設(shè)計的約束條件和計算方法,從系統(tǒng)的控制特性、濾波特性、阻尼特性等方面對無源阻尼和有源阻尼控制策略進(jìn)行了研究和分析。 理想狀態(tài)下調(diào)制只產(chǎn)生了高頻諧波,且易被濾波器消除,但實際的非理想狀態(tài)和外部擾動會注入低次諧波,因此需要對電流控制器進(jìn)一步優(yōu)化,來補償或消除低次諧波污染。本文建立了單相LCL型并網(wǎng)逆變器的系統(tǒng)模型,量化分析了開關(guān)管固有特性和死區(qū)效應(yīng),直流電壓二次脈動及電網(wǎng)諧波擾動的低次諧波注入。故而針對性提出了諧波補償和抑制策略,最后采用一種重復(fù)控制與狀態(tài)反饋相結(jié)合,并加入直流電壓前饋解耦和電網(wǎng)電壓前饋補償?shù)姆桨浮?本文開發(fā)了基于DSP和PV-IPM的3kW單相組串型并網(wǎng)逆變器,完成主功率電路、控制電路及控制部分軟件程序的設(shè)計,并通過Matlab/Simulink仿真和逆變器樣機實驗,驗證了諧波分析的合理性和復(fù)合控制策略的有效性。
[Abstract]:Grid-connected inverters are widely used in the field of photovoltaic, wind and other renewable energy generation. As the interface between distributed power supply and power grid, the harmonic suppression ability and the quality of input current waveform are important performance indexes of grid-connected inverters. In this paper, the current control strategy of single-phase LCL grid-connected inverter is studied. Based on DSP and PV-IPM, the 3kW cascade inverter is designed, and the simulation and experimental verification are completed. In this paper, the two-stage grid-connected inverter system structure is selected. The former DC/DC is mainly used to meet the requirements of maximum power point tracking and DC voltage input range, while the DC/AC stage is used for inverter and grid-connected control. Firstly, the topology circuits of common DC/DC converter and DC/AC converter are studied, and the advantages and disadvantages of each topology are analyzed. The modulation principle, the modulation characteristics and harmonic characteristics of the bipolar and unipolar double frequency SPWM are further studied in this paper. The modulation principle of the Boost circuit to realize the SPWM is also studied. The LCL filter attenuates at the high frequency by-60dB/ ten-fold frequency, which is better than the pure inductor filter. However, its control model is a third-order system, and there is a very high resonance peak at the resonant frequency. This often causes the distortion of current waveform, so it is necessary to adopt appropriate control strategy to improve the damping of the system and enhance the stability of the control system. The traditional passive damping scheme is the series or parallel resistance in the filter, but the corresponding damping loss and the weakening of the high frequency harmonic suppression ability are not satisfactory. The typical active damping techniques include split capacitance method, capacitance current internal loop feedback, and so on. No beat control, etc. In this paper, the control strategies of passive damping and active damping are studied and analyzed from the aspects of system control characteristics, filtering characteristics, damping characteristics and so on. The constraint conditions and calculation methods for the design of LCL type grid-connected filters are discussed in this paper. The modulation only produces high-frequency harmonics in ideal state and is easy to be eliminated by filter, but the actual non-ideal state and external disturbance will inject low-order harmonics, so it is necessary to further optimize the current controller to compensate or eliminate the low-order harmonic pollution. In this paper, the system model of single-phase LCL grid-connected inverter is established, and the inherent characteristics and dead-time effect of switch tube, the second pulsation of DC voltage and the low-order harmonic injection of harmonic disturbance in power network are quantitatively analyzed. Therefore, the strategy of harmonic compensation and suppression is put forward. At last, a scheme of DC voltage feedforward decoupling and grid voltage feedforward compensation is adopted, which combines repetitive control with state feedback. In this paper, a 3kW single-phase series grid-connected inverter based on DSP and PV-IPM is developed. The main power circuit, control circuit and some software programs of the inverter are designed. The simulation of Matlab/Simulink and the prototype experiment of the inverter are carried out. The rationality of harmonic analysis and the effectiveness of compound control strategy are verified.
【學(xué)位授予單位】：東華大學(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10條

1 劉飛;殷進(jìn)軍;周彥;段善旭;;LCL濾波器的三相光伏逆變器雙環(huán)控制策略[J];電力電子技術(shù);2008年09期

2 王立喬;;正弦波逆變器脈寬調(diào)制技術(shù)的調(diào)制模型分析[J];電力系統(tǒng)自動化;2008年17期

3 袁濤;鄭建勇;曾偉;康靜;;IPM智能功率模塊電路設(shè)計及其在有源濾波器裝置中應(yīng)用[J];電力自動化設(shè)備;2007年05期

4 伍家駒;王文婷;李學(xué)勇;杉本英彥;;單相SPWM逆變橋輸出電壓的諧波分析[J];電力自動化設(shè)備;2008年04期

5 徐順剛;許建平;曹太強;;電壓電流雙閉環(huán)反饋逆變器并聯(lián)控制[J];電力自動化設(shè)備;2009年10期

6 楊會敏;宋建成;;基于雙環(huán)控制的單相電壓型PWM逆變器建模與仿真[J];電氣技術(shù);2008年05期

7 朱瑞林;韓金剛;湯天浩;;并網(wǎng)逆變器LCL型濾波器的設(shè)計及有源補償[J];電源學(xué)報;2012年03期

8 孔曉麗;陳顯峰;續(xù)艷鑫;;基于DSP的光伏電池最大功率點跟蹤系統(tǒng)[J];電子技術(shù);2010年02期

9 謝少軍;許津銘;;LCL濾波并網(wǎng)逆變器的電流控制技術(shù)研究綜述[J];電源學(xué)報;2012年04期

10 胡興軍;;太陽能光伏發(fā)電產(chǎn)業(yè)發(fā)展綜述[J];上海電力;2008年04期

，

本文編號：2448440