分布式直流供电系统的光伏接口单元研究
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摘要
太阳能作为资源丰富、分布广泛的一种清洁能源,是目前新能源发展的主要方向之一。而光伏发电又是人类目前开发和利用太阳能的最热门的一类方式。作为光伏发电系统的核心部分,光伏逆变器如果以单机电源方式接入电网,会存在着成本高、控制困难等问题,所以有学者提出了分布式供电系统(微电网)的概念,即将单机电源以组网的方式接入电网。
近年来,随着人们对分布式供电系统研究的不断深入,分布式直流供电系统——即直流微网,得到了国际上众多研究机构的重视。作为微电网的一种组网方式,分布式直流供电系统具有能量变换环节少、系统效率高和控制方便等诸多优点,同时也使包括光伏发电在内的很多分布式电源有了新的减小成本、提高能源利用率的发展空间。
本文针对分布式直流供电系统,以光伏接口单元为目标展开研究。在选择光伏直直变换器拓扑时,考虑简单、高效以及宽的电压输入范围的要求,选择了双管Buck-boost拓扑。该拓扑具有升/降压、输入输出同极性和非隔离等特点,然而在电感电流连续模式下,其自身二极管的反向恢复问题成了效率进一步提高的瓶颈。本文采用了一种利用耦合电感将电路中电感电流转移的方法来解决该变换器的反向恢复问题,进行了相关理论公式的推导,给出了参数设计方法和损耗分析。
为了比较好的使变换器和直流微网协调工作,架起光伏电池板和直流微网之间可靠的桥梁,变换器需要一个特定的输出特性。该特性要求变换器能够根据直流母线电压的不同,分别工作在线性稳压区和光伏最大功率跟踪区二种状态。本文根据该要求提出了光伏接口变换器的一种控制策略,并基于对变换器的小信号建模,给出了控制环路的设计过程。
根据所提出的研究目标,结合拓扑本身以及对其控制技术的研究,设计了一个采用数字控制的3kW光伏接口,本文给出了功率电路和控制电路的设计过程。最后通过对光伏接口进行的仿真和实验,证明了关于所用拓扑和其控制技术理论研究的正确性。
Solar energy, as one of the most rich and widely distributed cleaning resources, has been paid more attention to the development of new resources. And the photovoltaic power has been one of the most popular ways to use solar energy. Also as the most important part of photovoltaic power generation system, the PV inverter when connected to the grid as single generation will be hard to control and have higher costs. So some scholars proposed a conception of distributed power supply system (micro-grid, or nanogrid), which means make these single generations form a micro-grid when connect to the grid.
In recent years, with the studies of distributed power supply system have advanced, the DC distributed power supply system has draw more attention to research institute all over the world. The DC distributed system can bring many advantages: less energy connection, higher efficiency and easier to control. On the other hand, it can also be helpful to the development of using new resources.
This paper, based on the DC distributed power supply system, has mainly researched on the PV interface converter. The topology has been chosed as two-switch Buck-boost converter, which has a wide range of input voltage and high efficiency. With advantages of buck/boost, same input and output polarityand isolated, it is widely used in many applications. However, in the CCM the reverse-recovery-related losses of its own diodes become a bottleneck to improve the efficiency. Based on some literature, this paper proposed a new circuit structure which shifts the inductor current to another path (using coupling inductor) to solve this problem. The relevant theoretical formula, method of parameter design and loss analysis has given.
In order to coordinate the DC micro-grid and the converter work well, the PV interface needs a special output Characteristics, which, according to the DC bus voltage, requires the converter can operate in different mode that is the MPPT mode and output voltage regulation mode. This paper proposes a control strategy to achieve the above modes, and gives the small-signal model of converter to design the control loop.
According to the proposed requirements, finally, this paper gives a design prototype of 3kW, including its main power circuit and control circuit. The simulation and experiment result shows the Correctness of the PV interface in topology and its control theory.
近年来,随着人们对分布式供电系统研究的不断深入,分布式直流供电系统——即直流微网,得到了国际上众多研究机构的重视。作为微电网的一种组网方式,分布式直流供电系统具有能量变换环节少、系统效率高和控制方便等诸多优点,同时也使包括光伏发电在内的很多分布式电源有了新的减小成本、提高能源利用率的发展空间。
本文针对分布式直流供电系统,以光伏接口单元为目标展开研究。在选择光伏直直变换器拓扑时,考虑简单、高效以及宽的电压输入范围的要求,选择了双管Buck-boost拓扑。该拓扑具有升/降压、输入输出同极性和非隔离等特点,然而在电感电流连续模式下,其自身二极管的反向恢复问题成了效率进一步提高的瓶颈。本文采用了一种利用耦合电感将电路中电感电流转移的方法来解决该变换器的反向恢复问题,进行了相关理论公式的推导,给出了参数设计方法和损耗分析。
为了比较好的使变换器和直流微网协调工作,架起光伏电池板和直流微网之间可靠的桥梁,变换器需要一个特定的输出特性。该特性要求变换器能够根据直流母线电压的不同,分别工作在线性稳压区和光伏最大功率跟踪区二种状态。本文根据该要求提出了光伏接口变换器的一种控制策略,并基于对变换器的小信号建模,给出了控制环路的设计过程。
根据所提出的研究目标,结合拓扑本身以及对其控制技术的研究,设计了一个采用数字控制的3kW光伏接口,本文给出了功率电路和控制电路的设计过程。最后通过对光伏接口进行的仿真和实验,证明了关于所用拓扑和其控制技术理论研究的正确性。
Solar energy, as one of the most rich and widely distributed cleaning resources, has been paid more attention to the development of new resources. And the photovoltaic power has been one of the most popular ways to use solar energy. Also as the most important part of photovoltaic power generation system, the PV inverter when connected to the grid as single generation will be hard to control and have higher costs. So some scholars proposed a conception of distributed power supply system (micro-grid, or nanogrid), which means make these single generations form a micro-grid when connect to the grid.
In recent years, with the studies of distributed power supply system have advanced, the DC distributed power supply system has draw more attention to research institute all over the world. The DC distributed system can bring many advantages: less energy connection, higher efficiency and easier to control. On the other hand, it can also be helpful to the development of using new resources.
This paper, based on the DC distributed power supply system, has mainly researched on the PV interface converter. The topology has been chosed as two-switch Buck-boost converter, which has a wide range of input voltage and high efficiency. With advantages of buck/boost, same input and output polarityand isolated, it is widely used in many applications. However, in the CCM the reverse-recovery-related losses of its own diodes become a bottleneck to improve the efficiency. Based on some literature, this paper proposed a new circuit structure which shifts the inductor current to another path (using coupling inductor) to solve this problem. The relevant theoretical formula, method of parameter design and loss analysis has given.
In order to coordinate the DC micro-grid and the converter work well, the PV interface needs a special output Characteristics, which, according to the DC bus voltage, requires the converter can operate in different mode that is the MPPT mode and output voltage regulation mode. This paper proposes a control strategy to achieve the above modes, and gives the small-signal model of converter to design the control loop.
According to the proposed requirements, finally, this paper gives a design prototype of 3kW, including its main power circuit and control circuit. The simulation and experiment result shows the Correctness of the PV interface in topology and its control theory.
引文
[1]刘助仁.新能源:缓解能源短缺和环境污染的希望[J],国际技术经济研究,2007,10(4):22-26.
[2]王建华.新能源发电战略[J],能源研究与利用,1999,2:40-42.
[3]米建华,王卓昆.电力行业节能现状与举措[J],中国科技投资,2006,9:29-31.
[4]贡光禹.世界新可再生能源发电现状与经验[J],能源研究通讯,2004,5:53-58.
[5]张丽香.可再生能源发电的发展现状及前景[J],电力学报,2008,23(1):29-33.
[6]由世俊,杨洪兴,娄承芝,等.建筑物用光伏集成系统在中国应用的前景[J],太阳能学报,2000,21(4):434-438.
[7]鲁宗相,王彩霞,闵勇,等.微电网研究综述[J].电力系统自动化.2007,3l(19):100-107.
[8]郑漳华,艾芊.微电网的研究现状及在我国的应用前景[J].电网技术,2008,32(16):27.31.
[9]赵宏伟,吴涛涛.基于分布式电源的微网技术[J].电力系统及其自动化学报,2008.20(1):121.128.
[10]王成山,肖朝霞,王守相.微网综合控制与分析[J].电力系统自动化,2008,32(7):98.103.
[11]楼书氢,李青锋,许化强,等.国外微电网的研究概况及其在我国的应用前景[J].华中电力,2009.3(22):56-59.
[12] http://zh.ssea-online.com/blog/view/8
[13] J. Bryan, R. Duke and S. Round, Decentralized control of a nanogrid[C], presented at Australasian Universities Power Engineering Conference, Christchurch, New Zealand, Sep., 2003.
[14] J. Bryan, R. Duke and S. Round, Distributed generation– nanogrid transmission and control options[C], International Power Engineering Conference, vol. 1, pp. 341–346, Nov., 2003.
[15] Dushan B., Igor C., Dong D., et al., Future Electronic Power Distribution Systems–A contemplative view–[C], 12th International Conference on Optimization of Electrical and Electronic Equipment, OPTIM 2010, pp1369-1380.
[16] Kakigano H., Miura Y., Ise T., et al. DC Voltage Control of the DC Micro-grid for Super High Quality Distribution[C], IEEE on Power Conversion Conference - Nagoya, 2007, PCC '07, pp518-525.
[17] Toshihiko T., Tsukasa S., Yusuke B., et al. A New Half-Bridge Based Inverter with the Reduced-Capacity DC Capacitors for DC Micro-Grid[C], IEEE on Energy Conversion Congressand Exposition (ECCE), Dec. 2010, pp 2564-2569.
[18] Lee J., Han B., Cha H., et al. Operational analysis of DC micro-grid using detailed model of distributed generation[C], Transmission & Distribution Conference & Exposition: Asia and Pacific, Oct. 2009, pp1-4
[19] B.Sahu, G.A.Rincon-Mora.A low voltage,dynamic,noninverting,synchronous Buck-boost converter for portable applications[J].IEEE Trans.on PE,2004,19(2):443~452.
[20] Haibo Q., Yicheng Z., Yongtao Y.Analysis of Buck-boost converters for fuel cell electric vehicles[C]. IEEE International Conference on Vehicular Electronics and Safety,2006:109~113.
[21]任小永,唐钊,阮新波,等.一种新颖的四开关Buck-boost变换器[J].中国电机工程学报,2008,28(21):15~19.
[22] Jingquan C., Dragan M., Robert E.Buck-boost PWM converters having two independently controlled switches[C]. IEEE PESC’01: 736~741.
[23] Young-Joo Lee, Alireza K., Arindam C., et al. Digital combination of Buck and Boost converters to control a positive Buck-boost converter and improve the output transients[J].IEEE Trans.on PE,2009,24(5): 1267~1279.
[24] Young-Joo Lee, Alireza K., Ali E., A compensation technique for smooth transitions in a noninverting Buck-boost converter [J]. IEEE Trans.on PE,2009,24(4):1002~1016.
[25] B. Sahu and G. A. Rincon-Mora., A high-efficiency, dual-mode, dynamic, buck-boost power supply IC for portable applications [C]. IEEE PESC, 2005:858-861.
[26] M.M.Jovanovic,A technique for reducing rectifier reverse recovery related losses in high power boost converters, IEEE Trans. Power Electron.,vol. 13,pp. 932–941,Sept. 1998.
[27] Q.Zhao,F.F.Tao,Fred C.Lee, et.al.A simple and effective method to alleviate the rectifier reverse-recovery problem in continuous-current-mode boost converters[J].IEEE Trans. on PE, 2001, 16(5), pp.649-658.
[28]倪龙贤,陈润若,丁顺,等,宽输入范围光伏并网发电系统,江苏省电工技术学会,2010,pp.76-77
[29]丁道宏,电力电子技术[M],北京,航空工业出版社, 1999.8.
[30] Muhammad H. Rashid,Power electronics: circuits, devices, and applications [M],北京,人民邮电出版社, 2007.
[31] RAJARSHI P,MAKSIMOVICD,Analysis of PWM Nonlinearity in Non-Inverting Buck-Boost Power Converters[C], IEEE on PESC, 2008
[32]王朗圆,吴晓波,一种多模式四开关降压-升压型DC-DC转换器[J],浙江大学,微电子学, 2009年03期
[33] Young-Joo Lee etc. Digital combination of Buck and Boost converters to control a positive Buck-Boost converter and improve the output transients[J], IEEE Transactions on PE,2009,pp. 1267-1279
[34]任小永.高效率高功率密度通信模块电源技术的研究,[博士学位论文],南京,南京航空航天大学2008.10
[35] Erickson,Robert W.,Fundamentals of Power Electronics. Second Edition.[M], Secaucus, NJ, USA: Kluwer Academic Publishers, 2000.
[36]徐德鸿,电力电子系统建模及控制[M],北京,机械工业出版社, 2006.1
[37] Trishan Esram and Trishan Esram, Comparison of Photovoltaic Array Maximum Power Point Tracking Techniques[J]. IEEE TRANS.on EC, JUNE 2007, pp.439-449
[38]黄瑶,黄洪全,电导增量法实现光伏系统的最大功率点跟踪控制[J],现代电子技术,2008年22期
[39]叶满园,官二勇,宋平岗.以电导增量法实现MPPT的单级光伏并网逆变器[J].电力电子技术, 2006, (02).
[40]司传涛,周林,张有玉,等.光伏阵列输出特性与MPPT控制仿真研究[J].华东电力,2010, (02).
[41]吴忠军,刘国海,廖志凌,硅太阳电池工程用数学模型参数的优化设计[J].电源技术2007(11)
[42] J A Gow,C D Manning. Development of photovoltaic arraymodel for use in power-electronics simulation studies [J]. IEEE Proc. Electric Power Appl.,1999:46 (2) pp. 193-200.
[43]苏建徽.硅太阳电池工程用数学模型[J].太阳能学报,2001,(22) pp. 409-412.
[44]孙园园,肖华锋,谢少军,太阳能电池工程简化模型的参数求取和验证[J].电力电子技术, 2009 (6)
[45]刘和平.TMS320LF240x DSP结构、原理及应用[M],北京,北京航空航天大学出版社,2005.
[46]赵修科.开关电源中磁性元器件[M].辽宁科技出版社,2004年8月.
[2]王建华.新能源发电战略[J],能源研究与利用,1999,2:40-42.
[3]米建华,王卓昆.电力行业节能现状与举措[J],中国科技投资,2006,9:29-31.
[4]贡光禹.世界新可再生能源发电现状与经验[J],能源研究通讯,2004,5:53-58.
[5]张丽香.可再生能源发电的发展现状及前景[J],电力学报,2008,23(1):29-33.
[6]由世俊,杨洪兴,娄承芝,等.建筑物用光伏集成系统在中国应用的前景[J],太阳能学报,2000,21(4):434-438.
[7]鲁宗相,王彩霞,闵勇,等.微电网研究综述[J].电力系统自动化.2007,3l(19):100-107.
[8]郑漳华,艾芊.微电网的研究现状及在我国的应用前景[J].电网技术,2008,32(16):27.31.
[9]赵宏伟,吴涛涛.基于分布式电源的微网技术[J].电力系统及其自动化学报,2008.20(1):121.128.
[10]王成山,肖朝霞,王守相.微网综合控制与分析[J].电力系统自动化,2008,32(7):98.103.
[11]楼书氢,李青锋,许化强,等.国外微电网的研究概况及其在我国的应用前景[J].华中电力,2009.3(22):56-59.
[12] http://zh.ssea-online.com/blog/view/8
[13] J. Bryan, R. Duke and S. Round, Decentralized control of a nanogrid[C], presented at Australasian Universities Power Engineering Conference, Christchurch, New Zealand, Sep., 2003.
[14] J. Bryan, R. Duke and S. Round, Distributed generation– nanogrid transmission and control options[C], International Power Engineering Conference, vol. 1, pp. 341–346, Nov., 2003.
[15] Dushan B., Igor C., Dong D., et al., Future Electronic Power Distribution Systems–A contemplative view–[C], 12th International Conference on Optimization of Electrical and Electronic Equipment, OPTIM 2010, pp1369-1380.
[16] Kakigano H., Miura Y., Ise T., et al. DC Voltage Control of the DC Micro-grid for Super High Quality Distribution[C], IEEE on Power Conversion Conference - Nagoya, 2007, PCC '07, pp518-525.
[17] Toshihiko T., Tsukasa S., Yusuke B., et al. A New Half-Bridge Based Inverter with the Reduced-Capacity DC Capacitors for DC Micro-Grid[C], IEEE on Energy Conversion Congressand Exposition (ECCE), Dec. 2010, pp 2564-2569.
[18] Lee J., Han B., Cha H., et al. Operational analysis of DC micro-grid using detailed model of distributed generation[C], Transmission & Distribution Conference & Exposition: Asia and Pacific, Oct. 2009, pp1-4
[19] B.Sahu, G.A.Rincon-Mora.A low voltage,dynamic,noninverting,synchronous Buck-boost converter for portable applications[J].IEEE Trans.on PE,2004,19(2):443~452.
[20] Haibo Q., Yicheng Z., Yongtao Y.Analysis of Buck-boost converters for fuel cell electric vehicles[C]. IEEE International Conference on Vehicular Electronics and Safety,2006:109~113.
[21]任小永,唐钊,阮新波,等.一种新颖的四开关Buck-boost变换器[J].中国电机工程学报,2008,28(21):15~19.
[22] Jingquan C., Dragan M., Robert E.Buck-boost PWM converters having two independently controlled switches[C]. IEEE PESC’01: 736~741.
[23] Young-Joo Lee, Alireza K., Arindam C., et al. Digital combination of Buck and Boost converters to control a positive Buck-boost converter and improve the output transients[J].IEEE Trans.on PE,2009,24(5): 1267~1279.
[24] Young-Joo Lee, Alireza K., Ali E., A compensation technique for smooth transitions in a noninverting Buck-boost converter [J]. IEEE Trans.on PE,2009,24(4):1002~1016.
[25] B. Sahu and G. A. Rincon-Mora., A high-efficiency, dual-mode, dynamic, buck-boost power supply IC for portable applications [C]. IEEE PESC, 2005:858-861.
[26] M.M.Jovanovic,A technique for reducing rectifier reverse recovery related losses in high power boost converters, IEEE Trans. Power Electron.,vol. 13,pp. 932–941,Sept. 1998.
[27] Q.Zhao,F.F.Tao,Fred C.Lee, et.al.A simple and effective method to alleviate the rectifier reverse-recovery problem in continuous-current-mode boost converters[J].IEEE Trans. on PE, 2001, 16(5), pp.649-658.
[28]倪龙贤,陈润若,丁顺,等,宽输入范围光伏并网发电系统,江苏省电工技术学会,2010,pp.76-77
[29]丁道宏,电力电子技术[M],北京,航空工业出版社, 1999.8.
[30] Muhammad H. Rashid,Power electronics: circuits, devices, and applications [M],北京,人民邮电出版社, 2007.
[31] RAJARSHI P,MAKSIMOVICD,Analysis of PWM Nonlinearity in Non-Inverting Buck-Boost Power Converters[C], IEEE on PESC, 2008
[32]王朗圆,吴晓波,一种多模式四开关降压-升压型DC-DC转换器[J],浙江大学,微电子学, 2009年03期
[33] Young-Joo Lee etc. Digital combination of Buck and Boost converters to control a positive Buck-Boost converter and improve the output transients[J], IEEE Transactions on PE,2009,pp. 1267-1279
[34]任小永.高效率高功率密度通信模块电源技术的研究,[博士学位论文],南京,南京航空航天大学2008.10
[35] Erickson,Robert W.,Fundamentals of Power Electronics. Second Edition.[M], Secaucus, NJ, USA: Kluwer Academic Publishers, 2000.
[36]徐德鸿,电力电子系统建模及控制[M],北京,机械工业出版社, 2006.1
[37] Trishan Esram and Trishan Esram, Comparison of Photovoltaic Array Maximum Power Point Tracking Techniques[J]. IEEE TRANS.on EC, JUNE 2007, pp.439-449
[38]黄瑶,黄洪全,电导增量法实现光伏系统的最大功率点跟踪控制[J],现代电子技术,2008年22期
[39]叶满园,官二勇,宋平岗.以电导增量法实现MPPT的单级光伏并网逆变器[J].电力电子技术, 2006, (02).
[40]司传涛,周林,张有玉,等.光伏阵列输出特性与MPPT控制仿真研究[J].华东电力,2010, (02).
[41]吴忠军,刘国海,廖志凌,硅太阳电池工程用数学模型参数的优化设计[J].电源技术2007(11)
[42] J A Gow,C D Manning. Development of photovoltaic arraymodel for use in power-electronics simulation studies [J]. IEEE Proc. Electric Power Appl.,1999:46 (2) pp. 193-200.
[43]苏建徽.硅太阳电池工程用数学模型[J].太阳能学报,2001,(22) pp. 409-412.
[44]孙园园,肖华锋,谢少军,太阳能电池工程简化模型的参数求取和验证[J].电力电子技术, 2009 (6)
[45]刘和平.TMS320LF240x DSP结构、原理及应用[M],北京,北京航空航天大学出版社,2005.
[46]赵修科.开关电源中磁性元器件[M].辽宁科技出版社,2004年8月.