光伏发电系统及其控制的研究
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摘要
在世界各国竞相发展绿色可再生能源的今天,太阳能凭其独特的优点受到了一致青睐。在太阳能的各种应用中,光伏应用备受关注。随着光伏组件价格的不断降低和光伏技术的发展,太阳能光伏发电系统将逐渐由现在的补充能源向替代能源过渡。独立发电(Stand-alone)系统和并网发电(Grid-connected)系统将成为光伏应用的主流。基于此,本文就光伏发电系统中的一些关键问题——如光伏阵列的最大功率点跟踪和蓄电池的优化管理、逆变器输出波形的改善和孤岛效应等方面做了详细的理论分析,建立了仿真模型,提出了相应的控制策略,并进行了实验验证。具体说来,本文的主要研究内容可归纳如下:
1.阐明了不同拓扑结构的光伏发电系统之性能和特点。
2.发展了以负载获得功率的变化代替传统的以光伏阵列输出功率的变化来进行最大功率跟踪的控制策略,在控制算法上采用改进的变步长电压扰动法,实现了光伏阵列的真正最大功率点跟踪(TMPPT);此外,在独立光伏发电系统中,通过控制算法的改进,实现了蓄电池的优化管理与光伏阵列TMPPT功能相结合。
3.详细分析了户用独立光伏发电系统中正弦波逆变器的工作原理,提出了基于输出电压反馈的模糊自适应PI控制策略,并进行了相应的实验研究,结果表明,该控制策略比传统的PI控制方式更加有效地改善了系统的动态性能。
4.详细分析了户用高频光伏并网发电系统的工作原理,首次提出了基于重复控制和电网电压前馈控制相结合的控制策略,并在Matlab╲Simulink环境下建立了相应的仿真模型,进行了仿真和实验研究,结果表明,该控制策略能够有效降低系统并网电流波形的总谐波畸变率(THD)。
5.详细分析、研究了发生孤岛效应的机理,完善了基于主动频率偏移方式实现反孤岛效应的策略,首次建立了Matlab╲Simulink环境下反孤岛效应的仿真模型,并进行了实验验证。
6.开发了基于高性能DSP芯片TMS320LF2407A的光伏发电系统的软硬件实验装置,实现了高速的数据采集、事件管理和复杂的控制算法,完善了系统的智能保护措施。
7.完善了基于VB6.0、高性能DSP芯片TMS320LF2407A和W77E58芯片的系统监控、显示和通讯软件,实现了对光伏发电系统的数据通讯和远距离监控。
At present, while most countries all over the world are developing green and renewable energy, solar energy is accepted commonly because of its unusual advantages. Photovoltaic (PV) systems are paid more attention to among its various applications. With price reduction of PV modules and development of PV technology, the role of PV generation systems is gradually changed from supplemental energy to substitute energy. And stand-alone and grid-connected PV generation systems will be the trend among PV applications. This paper deals with such key problems as true maximum power point tracking (TMPPT) of PV array and optimum management of battery, improvement of inverter output wave, islanding effect and so on by establishing related simulation models, applying novel control strategies and experiments validation. The more details about author's work are as follows:1. The performances and characteristics of PV generation systems with different topologies are described in details.2. A novel control strategy is developed in which power variation of load is used instead of the power variation of PV array output to track the maximum power point of PV array. And TMPPT of PV array is realized by applying the variable step voltage disturbance control algorithm. In addition to that, the function combining the optimum management of battery with the TMPPT of PV array is attained by improving the control algorithm in stand-alone PV generation systems .3. The sine-wave inverter operation principle of residential stand-alone PV generation system is analyzed in details. And the fuzzy adaptive PI control strategy based on the output voltage feedback is presented, corresponding experiments are done. The experiment results show that the control strategy above improves dynamic performance of system more efficiently than traditional PI control.4. The operation principle of residential high frequency PV grid-connected generation system is analyzed in details. The novel strategy which combines the repetitive control with the utility voltage feedforward control is presented for the first time. The corresponding simulation model is setup, related simulations and experiments are done. The results show that the total harmonic distortion (THD) of grid-connected current wave is reduced by strategy above.5. The mechanism of islanding occurring is analyzed and studied in details. The strategy of anti-islanding based on the active frequency drifting is improved. And the corresponding
simulation model under Matlab/Simulink environment is established for the first time and some experiments are done according to the strategy above.6. The software and hardware experiment set of PV generation system based on the high performance DSP chip of TMS320LF2407A is developed with functions of high speed data acquisition, event managements, complex control algorithm and intelligent protection measures of the system .7. The system monitor, display and communication software which based on the VB6.0, high performance DSP chip of TMS320LF2407A and W77E58 chip, is improved, which provides communication and remote monitor of PV generation system.
1.阐明了不同拓扑结构的光伏发电系统之性能和特点。
2.发展了以负载获得功率的变化代替传统的以光伏阵列输出功率的变化来进行最大功率跟踪的控制策略,在控制算法上采用改进的变步长电压扰动法,实现了光伏阵列的真正最大功率点跟踪(TMPPT);此外,在独立光伏发电系统中,通过控制算法的改进,实现了蓄电池的优化管理与光伏阵列TMPPT功能相结合。
3.详细分析了户用独立光伏发电系统中正弦波逆变器的工作原理,提出了基于输出电压反馈的模糊自适应PI控制策略,并进行了相应的实验研究,结果表明,该控制策略比传统的PI控制方式更加有效地改善了系统的动态性能。
4.详细分析了户用高频光伏并网发电系统的工作原理,首次提出了基于重复控制和电网电压前馈控制相结合的控制策略,并在Matlab╲Simulink环境下建立了相应的仿真模型,进行了仿真和实验研究,结果表明,该控制策略能够有效降低系统并网电流波形的总谐波畸变率(THD)。
5.详细分析、研究了发生孤岛效应的机理,完善了基于主动频率偏移方式实现反孤岛效应的策略,首次建立了Matlab╲Simulink环境下反孤岛效应的仿真模型,并进行了实验验证。
6.开发了基于高性能DSP芯片TMS320LF2407A的光伏发电系统的软硬件实验装置,实现了高速的数据采集、事件管理和复杂的控制算法,完善了系统的智能保护措施。
7.完善了基于VB6.0、高性能DSP芯片TMS320LF2407A和W77E58芯片的系统监控、显示和通讯软件,实现了对光伏发电系统的数据通讯和远距离监控。
At present, while most countries all over the world are developing green and renewable energy, solar energy is accepted commonly because of its unusual advantages. Photovoltaic (PV) systems are paid more attention to among its various applications. With price reduction of PV modules and development of PV technology, the role of PV generation systems is gradually changed from supplemental energy to substitute energy. And stand-alone and grid-connected PV generation systems will be the trend among PV applications. This paper deals with such key problems as true maximum power point tracking (TMPPT) of PV array and optimum management of battery, improvement of inverter output wave, islanding effect and so on by establishing related simulation models, applying novel control strategies and experiments validation. The more details about author's work are as follows:1. The performances and characteristics of PV generation systems with different topologies are described in details.2. A novel control strategy is developed in which power variation of load is used instead of the power variation of PV array output to track the maximum power point of PV array. And TMPPT of PV array is realized by applying the variable step voltage disturbance control algorithm. In addition to that, the function combining the optimum management of battery with the TMPPT of PV array is attained by improving the control algorithm in stand-alone PV generation systems .3. The sine-wave inverter operation principle of residential stand-alone PV generation system is analyzed in details. And the fuzzy adaptive PI control strategy based on the output voltage feedback is presented, corresponding experiments are done. The experiment results show that the control strategy above improves dynamic performance of system more efficiently than traditional PI control.4. The operation principle of residential high frequency PV grid-connected generation system is analyzed in details. The novel strategy which combines the repetitive control with the utility voltage feedforward control is presented for the first time. The corresponding simulation model is setup, related simulations and experiments are done. The results show that the total harmonic distortion (THD) of grid-connected current wave is reduced by strategy above.5. The mechanism of islanding occurring is analyzed and studied in details. The strategy of anti-islanding based on the active frequency drifting is improved. And the corresponding
simulation model under Matlab/Simulink environment is established for the first time and some experiments are done according to the strategy above.6. The software and hardware experiment set of PV generation system based on the high performance DSP chip of TMS320LF2407A is developed with functions of high speed data acquisition, event managements, complex control algorithm and intelligent protection measures of the system .7. The system monitor, display and communication software which based on the VB6.0, high performance DSP chip of TMS320LF2407A and W77E58 chip, is improved, which provides communication and remote monitor of PV generation system.
引文
[1] 赵玉文.“光伏发电在本世纪人类能源发展中的战略地位”.合肥工业大学讲座,2001.
[2] 赵玉文.“太阳能光伏技术的发展概况”.第五届全国光伏技术学术研讨会论文集,1998.
[3] Kosuke Kurokawa, Daisuke Uchida, Kenji Otani and Tadatoshi Sugiura, "Realistic PV Performance Values Obtained By A Number Of Grid-Connected Systems In Japan" 8 th Intern. Conf. on Solar Energy in High Latitudes, Edmonton, Canada, Aug, 1999.
[4] Larry Goldstein, John Mortensen, and David Trickett, "Grid-Connected Renewable-Electric Policies in the European Union", National Renewable Energy Laboratory, May, 1999.
[5] 太阳能利用现状及对策.2004,5,16.
[6] http://www.epsea.org/pv.html.
[7] 刘荣主编.自然能供电技术.科学出版社,2000,9.
[8] 蔡兆文等.21世纪中国风力发电展望.
[9] 严陆光等.太阳能与风力发电的现状与展望.电网技术,1995,5.
[10] 茆美琴.风光柴蓄复合发电及其智能控制系统研究[D].合肥工业大学,2004,6.
[11] 王斯成.光伏发电的前景和问题.国际电力,1997第四期.
[12] 黄讯.我国光伏发电的现状及市场展望.中国环保产业,2003,5.
[13] 中国资源综合利用协会可再生能源专业委员会.中国光伏发电的技术现状及展望.可再生能源.2002.3.
[14] 刘凤君.正弦波逆变器[M].科学出版社,2000,11.
[15] 王兆安,黄俊.电力电子技术[M].机械工业出版社,2002,1.
[2] 赵玉文.“太阳能光伏技术的发展概况”.第五届全国光伏技术学术研讨会论文集,1998.
[3] Kosuke Kurokawa, Daisuke Uchida, Kenji Otani and Tadatoshi Sugiura, "Realistic PV Performance Values Obtained By A Number Of Grid-Connected Systems In Japan" 8 th Intern. Conf. on Solar Energy in High Latitudes, Edmonton, Canada, Aug, 1999.
[4] Larry Goldstein, John Mortensen, and David Trickett, "Grid-Connected Renewable-Electric Policies in the European Union", National Renewable Energy Laboratory, May, 1999.
[5] 太阳能利用现状及对策.2004,5,16.
[6] http://www.epsea.org/pv.html.
[7] 刘荣主编.自然能供电技术.科学出版社,2000,9.
[8] 蔡兆文等.21世纪中国风力发电展望.
[9] 严陆光等.太阳能与风力发电的现状与展望.电网技术,1995,5.
[10] 茆美琴.风光柴蓄复合发电及其智能控制系统研究[D].合肥工业大学,2004,6.
[11] 王斯成.光伏发电的前景和问题.国际电力,1997第四期.
[12] 黄讯.我国光伏发电的现状及市场展望.中国环保产业,2003,5.
[13] 中国资源综合利用协会可再生能源专业委员会.中国光伏发电的技术现状及展望.可再生能源.2002.3.
[14] 刘凤君.正弦波逆变器[M].科学出版社,2000,11.
[15] 王兆安,黄俊.电力电子技术[M].机械工业出版社,2002,1.