单相光伏并网逆变器研究
摘要
作为光伏并网系统核心功率变换部件,光伏并网逆变器两项主要功能为确保光伏电池工作在最大功率点及向电网单位功率因数馈电。要完成上述两项功能,必须对光伏并网逆变器主电路拓扑结构选择、调制方式确定、主电路参数设计、控制策略设计优化及系统整体软件设计等进行深入研究。
本论文首先对并网逆变器主电路进行了研究与设计,确定了带工频变压器全桥逆变拓扑结构,对比分析了两种SPWM调制方式并确定了单极性SPWM调制方式,对输出滤波器及直流母线电容参数进行了研究分析,确定了带阻尼电阻的LCL输出滤波器结构。
其次,对光伏并网逆变器双环控制策略进行了详细的分析与研究,对并网逆变器进行建模,通过对比分析几种电流控制方式确定了PI控制的电流瞬时值反馈控制策略,通过对开环及闭环特性进行仿真分析从而对电流环控制参数进行了优化设计;对电压外环进行了建模,并通过解析及仿真方式对电压环参数进行了优化。
再次,对光伏并网逆变器MPPT控制策略进行了分析与研究,对光伏电池输出特性进行了分析,并对Boost电路MPPT控制原理进行了研究,通过对比分析确定了干扰观测法作为本论文的MPPT控制策略,并对该方法进行了改进与实现。
最后,设计并实现光伏并网逆变器数字控制策略,对数字锁相环进行研究与设计,设计与实现了系统软件控制策略,并给出相关实验波形。
As the main power conversion unit of the Photovoltaic(PV) grid-connected(GC) system, the PV GC inverter has two main tasks. One is ensure that the PV modules is operated at the maximum power point(MPP). The other is to inject a sinusoidal current with unit power factor to the grid. The main circuit topology, modulation identification, main circuit parameter design, control strategy and the overall system software design optimization of the PV GC inverter must be studied in depth to accomplish these two tasks.
The main circuit of the PV GC inverter is initially studied in this thesis. The topology of full-bridge inverter with line-transformer is determined after analysis. With the comparing and analyzing of two main SPWM modulations, the unipolar SPWM modulation is determined. After the output filter and the DC-link capacitor is analyzed and studied, the LCL-filter with damping resistor is determined as the GC filter.
Secondly, the dual-loop control strategy of the PV GC inverter is analyzed and studied in detail. With the modeling of the GC inverter, the current instantaneous control strategy with PI control is determined by comparing and analyzing several current control mode and the control parameters of the current loop are optimized with the simulation of the characteristics of open-loop and close-loop. With the modeling of DC-link voltage loop, the parameters of the voltage loop is optimized through analytical and simulation methods.
The MPPT control strategy of the PV GC inverter is then analyzed and studied. With the analyzing of PV cell output characteristics, the MPPT control theory is studied based on Boost topology. The perturb and observe(P&O) method is determined, improved and implemented as the MPPT control strategy of this thesis by comparison and analysis.
Consequently, the digital control strategy of the PV GC inverter is designed and implemented. The digital phase-lock-loop(PLL) and the software control strategy of the system is researched and studied and then the experimental waveforms are given and analyzed.
本论文首先对并网逆变器主电路进行了研究与设计,确定了带工频变压器全桥逆变拓扑结构,对比分析了两种SPWM调制方式并确定了单极性SPWM调制方式,对输出滤波器及直流母线电容参数进行了研究分析,确定了带阻尼电阻的LCL输出滤波器结构。
其次,对光伏并网逆变器双环控制策略进行了详细的分析与研究,对并网逆变器进行建模,通过对比分析几种电流控制方式确定了PI控制的电流瞬时值反馈控制策略,通过对开环及闭环特性进行仿真分析从而对电流环控制参数进行了优化设计;对电压外环进行了建模,并通过解析及仿真方式对电压环参数进行了优化。
再次,对光伏并网逆变器MPPT控制策略进行了分析与研究,对光伏电池输出特性进行了分析,并对Boost电路MPPT控制原理进行了研究,通过对比分析确定了干扰观测法作为本论文的MPPT控制策略,并对该方法进行了改进与实现。
最后,设计并实现光伏并网逆变器数字控制策略,对数字锁相环进行研究与设计,设计与实现了系统软件控制策略,并给出相关实验波形。
As the main power conversion unit of the Photovoltaic(PV) grid-connected(GC) system, the PV GC inverter has two main tasks. One is ensure that the PV modules is operated at the maximum power point(MPP). The other is to inject a sinusoidal current with unit power factor to the grid. The main circuit topology, modulation identification, main circuit parameter design, control strategy and the overall system software design optimization of the PV GC inverter must be studied in depth to accomplish these two tasks.
The main circuit of the PV GC inverter is initially studied in this thesis. The topology of full-bridge inverter with line-transformer is determined after analysis. With the comparing and analyzing of two main SPWM modulations, the unipolar SPWM modulation is determined. After the output filter and the DC-link capacitor is analyzed and studied, the LCL-filter with damping resistor is determined as the GC filter.
Secondly, the dual-loop control strategy of the PV GC inverter is analyzed and studied in detail. With the modeling of the GC inverter, the current instantaneous control strategy with PI control is determined by comparing and analyzing several current control mode and the control parameters of the current loop are optimized with the simulation of the characteristics of open-loop and close-loop. With the modeling of DC-link voltage loop, the parameters of the voltage loop is optimized through analytical and simulation methods.
The MPPT control strategy of the PV GC inverter is then analyzed and studied. With the analyzing of PV cell output characteristics, the MPPT control theory is studied based on Boost topology. The perturb and observe(P&O) method is determined, improved and implemented as the MPPT control strategy of this thesis by comparison and analysis.
Consequently, the digital control strategy of the PV GC inverter is designed and implemented. The digital phase-lock-loop(PLL) and the software control strategy of the system is researched and studied and then the experimental waveforms are given and analyzed.
引文
[1]周孝信,曹一家.我国发展大规模非水可再生能源发电的前景[J].电力科学与技术学报. 2008, 23(1): 2-7.
[2] F. Blaabjerg, R. Teodorescu, M. Liserre. Overview of Control and Grid Synchronization for Distributed Power Generation Systems[J]. IEEE Transactions On Industrial Electronics, 2006, 53(5): 1398-1409.
[3] P. Nema, R. K. Nema, S. Rangnekar. A current and future state of art development of hybrid system using wind and PV-solar: A review[J]. Renewable and Sustainable Energy Review, 2009, 13: 2096-2103.
[4] F. Blaabjerg, Zhe Chen, S. B. Kjaer. Power Electronics as Efficient Interface in Dispersed Power Generation Systems[J]. IEEE Transactions On Power Electronics, 2004, 19(5): 1184-1194.
[5] G. K. Andersen, C. Klumpner, S. B. Kjaer, et al. A New Green Power Inverter for Fuel Cells[C]. IEEE Power Electronics Specialists Conference, 2002, 2: 727-733.
[6] European Renewable Energy Council. Renewable Energy Scenario to 2040[R]. 2004: 1-16.
[7] B. E. Turkay, A. Y. Telli. Economic analysis of stand alone and grid connected hybrid energy systems[C]. International Conference On Electrical and Electronics Engineering, 2009: 34-39.
[8] K. T. Tan, P. L. So, Y. C. Chu, et al. Modeling, Control and Simulation of a Photovoltaic Power System for Grid-Connected and Stand-alone Applications[C]. International Power Engineering Conference, 2010: 608-613.
[9] Deepak Paramashivan Kaundinya, P. Balachandra, N.H. Ravindranath. Grid-connected versus stand-alone energy systems for decentralized power—A review of literature[J]. Renewable and Sustainable Energy Reviews, 2009, 13: 2041-2050.
[10] Semi PV Group,中国光伏产业联盟. 2011中国光伏产业发展报告[R/OL]. 2011: 1-12.
[11] G. Ertasgin, D. M. Whaley, N. Ertugrul, et al. Implementation and Performance Evaluation of a Low-Cost Current-Source Grid-Connected Inverter for PV Applications[C]. IEEE International Conference On Sustainable EnergyTechnologies, 2008: 939-944.
[12] B. S. Prasad, S. Jain, V. Agarwal, et al. Universal Single-Stage Grid-Connected Inverter[J]. IEEE Transactions On Energy Conversion, 2008, 23(1): 128-137.
[13] S. B. Kjaer, J. K. Pedersen, Frede Blaabjerg. A Review of Single-Phase Grid-Connected Inverters for Photovoltaic Modules[J]. IEEE Transactions On Industry Applications, 2005, 41(5): 1292-1306.
[14] Yi Huang, Fang Z. Peng. Survey of the Power conditioning System for PV Power Generation[C]. IEEE PESC’06, 2006: 1-6.
[15] J. M. A. Myrzik, M. Calais. String and Module Integrated Inverters for Single-Phase Grid Connected Photovoltaic Systems-A Review[C]. IEEE Bologna PowerTech Conference, 2003, 2: 8-15.
[16] H. Haeberlin, B. Fachhochschule. Evolution of Inverters for Grid connected PV-Systems from 1989 to 2000[C]. 17th European Photovoltaic Solar Energy Conference, 2001.
[17] M. Meinhardt, G. Cramer. Past, present and future of grid connected photovoltaic and hybrid-power-systems[C]. IEEE Power Engineering Society Summer Meeting, 2000: 1283-1288.
[18] B. Verhoeven. Utility Aspects of Grid Connected Photovoltaic Power Systems[R]. International Energy Agency Photovoltaic Power Systems, 1998.
[19]余运江.单相光伏并网逆变器的研究[D].杭州:浙江大学学位论文, 2008:6-14.
[20] S. B. Kjaer, J. K. Pedersen, F. Blaabjerg. Power Inverter Topologies for Photovoltaic Modules-A Review[C]. 37th IAS Annual Meeting, 2002: 782-788.
[21]许颇.基于Z源型逆变器的光伏并网发电系统的研究[D].合肥:合肥工业大学学位论文, 2006: 4-7.
[22] F. Z. Peng. Z-Source Inverter[J]. IEEE Transactions on Industry Applications, 2003, 39(2): 504-510.
[23] Yaosuo Xue, Liuchen Chang, S. B. Kjaer. Topologies of Sing-Phase Inverters for Small Distributed Power Generators: An Overview[J]. IEEE Transactions On Power Electronics, 2004, 19(5): 1305-1314.
[24] Quan Li, Peter Wolfs. A Review of the Single Phase Photovoltaic Module Integrated Converter Topologies With Three Different DC Link Configurations[J]. IEEE Transactions On Power Electronics, 2008, 23(3): 1320-1333.
[25] J. M. Carrasco, L. G.. Franquelo, J. T. Bialasiewicz, et al. Power-Electronic Systems for the Grid Integration of Renewable Energy Sources: a Survey[J]. IEEE Transactions On Industrial Electronics, 2006, 53(4): 1002-1016.
[26] R. Gonzalez, J. Lopez, P. Sanchis, L. Marroyo. Transformerless inverter for single-phase photovoltaic systems[J]. IEEE Transactions on Power Electronics, 2007, 22(2): 693-697.
[27] Huafeng Xiao, Shaojun Xie. Leakage Current Analytical Model and Application in Single-Phase Transformerless Photovoltaic Grid-Connected Inverter[J]. IEEE Transactions on Electromagnetic Compatibility, 2010, 52(4): 902-913.
[28] M. A. Eltawil, Zhengming Zhao. Grid-connected photovoltaic power systems: Technical and potential problems—A review[J]. Renewable and Sustainable Energy Reviews, 2010, 14: 112-119.
[29] O. Lopez, R. Teodorescu, F. Freijedo, et al. Eliminating ground current in a transformerless photovoltaic application[J]. IEEE Transactions on Energy Conversion, 2010, 25(1): 140-147.
[30] J. Rodriguez, J. S. Lai, F. Z. Peng. Multilevel Inverters: A Survey of Topologies, Control, and Applications[J]. IEEE On Industrial Electronics, 2002, 49(4): 724-738.
[31] 2011年中国及海外太阳能光伏产业发展报告[R/OL]. http:// wenku. baidu. com/ view/ e72a45f9941ea76e58fa04d1.html.
[32]赵玉文.我国太阳能光伏产业发展形势和思考[J].世界科技研究和发展, 2003, 25(4): 31-38.
[33]赵玉文. 21世纪我国太阳能利用发展趋势[J].中国电力, 2000, 33(9): 73-77.
[34] Les Bowtell, Tony Ahfock. Comparison Between Unipolar and Bipolar Single Phase Grid-connected Inverters for PV Applications[C]. Australasian Universities Power Engineering Conference, 2007: 1-5.
[35] Timothy CY Wang, Zhihong Ye, Gautam Sinha, Xiaoming Yuan. Output Filter Design for a Grid-interconnected Three-Phase Inverter[C]. IEEE PESC’03. 2003: 779-784.
[36] M. Liserre, F. Blaabjerg, S. Hansen. Design and Control of an LCL-filter based Three-phase Active Rectifier[J]. IEEE Transactions on Industry Applications. 2005, 9: 1281~1291.
[37]刘飞,查晓明,段善旭.三相并网逆变器LCL滤波器的参数设计与研究[J].电工技术学报. 2010, 3: 110-115.
[38]王要强,吴凤江,孙力,孙奎.阻尼损耗最小化的LCL滤波器参数优化设计[J].中国电机工程学报, 2010, 30(27): 90-95.
[39]郭伟峰,徐殿国,武健,王立国. LCL有源电力滤波器新型控制方法[J].中国电机工程学报, 2010, 30(3): 42-48.
[40] S. B. Kjaer. Design and Control of an inverter for Photovoltaic Applications[D]. Ph.D. dissertation, Aalborg University, 2005.
[41]赵清林,郭小强,邬伟扬.单相逆变器并网控制技术研究[J].中国电机工程学报, 2007, 27(16): 60-64.
[42]冯玉,刘强,郭珂,黄剑,周林.单相光伏并网逆变器建模与控制技术研究[C].第四届中国高校电力电子及电力传动学术年会论文集, 2007: 529-536.
[43] R. Teodorescu, F. Blaabjerg, U. Borup, M. Liserre. A New Structure for Grid-connected LCL PV Inverters With Zero Steady-State Error ans Selective Harmonic Compensation[C]. Applied Power Electronics Conference and Exposition, APEC’04, 19th Annual IEEE, 2004, 1:580-581.
[44] Xiaoming Yuan, W. Merk, H. Stemmler, et al. Stationary-Frame Generalized Integrators for Current Control of Active Power Filters With Zero Steady-State Error for Current Harmonics of Concern Under Unbalanced and Distorted Operating Conditions[J]. IEEE Transactions On Industry Applications, 2002, 38(2): 523-532.
[45]夏德钤,翁贻方.自动控制理论[M].北京:机械工业出版社, 2004: 190.
[46] Trishan Esram, Patrick L. Chapman. Comparison of Photovoltaic Array Maximum Power Point Tracking Techniques[J]. IEEE Transactions on Energy Conversion, 2007, 22(2): 439-449.
[47] Weidong Xiao, William G. Dunford. A Modified Adaptive Hill Climbing MPPT Method for Photovoltaic Power Systems[C]. IEEE Power Electronics Specialists Conference, 2004: 1957-1963.
[2] F. Blaabjerg, R. Teodorescu, M. Liserre. Overview of Control and Grid Synchronization for Distributed Power Generation Systems[J]. IEEE Transactions On Industrial Electronics, 2006, 53(5): 1398-1409.
[3] P. Nema, R. K. Nema, S. Rangnekar. A current and future state of art development of hybrid system using wind and PV-solar: A review[J]. Renewable and Sustainable Energy Review, 2009, 13: 2096-2103.
[4] F. Blaabjerg, Zhe Chen, S. B. Kjaer. Power Electronics as Efficient Interface in Dispersed Power Generation Systems[J]. IEEE Transactions On Power Electronics, 2004, 19(5): 1184-1194.
[5] G. K. Andersen, C. Klumpner, S. B. Kjaer, et al. A New Green Power Inverter for Fuel Cells[C]. IEEE Power Electronics Specialists Conference, 2002, 2: 727-733.
[6] European Renewable Energy Council. Renewable Energy Scenario to 2040[R]. 2004: 1-16.
[7] B. E. Turkay, A. Y. Telli. Economic analysis of stand alone and grid connected hybrid energy systems[C]. International Conference On Electrical and Electronics Engineering, 2009: 34-39.
[8] K. T. Tan, P. L. So, Y. C. Chu, et al. Modeling, Control and Simulation of a Photovoltaic Power System for Grid-Connected and Stand-alone Applications[C]. International Power Engineering Conference, 2010: 608-613.
[9] Deepak Paramashivan Kaundinya, P. Balachandra, N.H. Ravindranath. Grid-connected versus stand-alone energy systems for decentralized power—A review of literature[J]. Renewable and Sustainable Energy Reviews, 2009, 13: 2041-2050.
[10] Semi PV Group,中国光伏产业联盟. 2011中国光伏产业发展报告[R/OL]. 2011: 1-12.
[11] G. Ertasgin, D. M. Whaley, N. Ertugrul, et al. Implementation and Performance Evaluation of a Low-Cost Current-Source Grid-Connected Inverter for PV Applications[C]. IEEE International Conference On Sustainable EnergyTechnologies, 2008: 939-944.
[12] B. S. Prasad, S. Jain, V. Agarwal, et al. Universal Single-Stage Grid-Connected Inverter[J]. IEEE Transactions On Energy Conversion, 2008, 23(1): 128-137.
[13] S. B. Kjaer, J. K. Pedersen, Frede Blaabjerg. A Review of Single-Phase Grid-Connected Inverters for Photovoltaic Modules[J]. IEEE Transactions On Industry Applications, 2005, 41(5): 1292-1306.
[14] Yi Huang, Fang Z. Peng. Survey of the Power conditioning System for PV Power Generation[C]. IEEE PESC’06, 2006: 1-6.
[15] J. M. A. Myrzik, M. Calais. String and Module Integrated Inverters for Single-Phase Grid Connected Photovoltaic Systems-A Review[C]. IEEE Bologna PowerTech Conference, 2003, 2: 8-15.
[16] H. Haeberlin, B. Fachhochschule. Evolution of Inverters for Grid connected PV-Systems from 1989 to 2000[C]. 17th European Photovoltaic Solar Energy Conference, 2001.
[17] M. Meinhardt, G. Cramer. Past, present and future of grid connected photovoltaic and hybrid-power-systems[C]. IEEE Power Engineering Society Summer Meeting, 2000: 1283-1288.
[18] B. Verhoeven. Utility Aspects of Grid Connected Photovoltaic Power Systems[R]. International Energy Agency Photovoltaic Power Systems, 1998.
[19]余运江.单相光伏并网逆变器的研究[D].杭州:浙江大学学位论文, 2008:6-14.
[20] S. B. Kjaer, J. K. Pedersen, F. Blaabjerg. Power Inverter Topologies for Photovoltaic Modules-A Review[C]. 37th IAS Annual Meeting, 2002: 782-788.
[21]许颇.基于Z源型逆变器的光伏并网发电系统的研究[D].合肥:合肥工业大学学位论文, 2006: 4-7.
[22] F. Z. Peng. Z-Source Inverter[J]. IEEE Transactions on Industry Applications, 2003, 39(2): 504-510.
[23] Yaosuo Xue, Liuchen Chang, S. B. Kjaer. Topologies of Sing-Phase Inverters for Small Distributed Power Generators: An Overview[J]. IEEE Transactions On Power Electronics, 2004, 19(5): 1305-1314.
[24] Quan Li, Peter Wolfs. A Review of the Single Phase Photovoltaic Module Integrated Converter Topologies With Three Different DC Link Configurations[J]. IEEE Transactions On Power Electronics, 2008, 23(3): 1320-1333.
[25] J. M. Carrasco, L. G.. Franquelo, J. T. Bialasiewicz, et al. Power-Electronic Systems for the Grid Integration of Renewable Energy Sources: a Survey[J]. IEEE Transactions On Industrial Electronics, 2006, 53(4): 1002-1016.
[26] R. Gonzalez, J. Lopez, P. Sanchis, L. Marroyo. Transformerless inverter for single-phase photovoltaic systems[J]. IEEE Transactions on Power Electronics, 2007, 22(2): 693-697.
[27] Huafeng Xiao, Shaojun Xie. Leakage Current Analytical Model and Application in Single-Phase Transformerless Photovoltaic Grid-Connected Inverter[J]. IEEE Transactions on Electromagnetic Compatibility, 2010, 52(4): 902-913.
[28] M. A. Eltawil, Zhengming Zhao. Grid-connected photovoltaic power systems: Technical and potential problems—A review[J]. Renewable and Sustainable Energy Reviews, 2010, 14: 112-119.
[29] O. Lopez, R. Teodorescu, F. Freijedo, et al. Eliminating ground current in a transformerless photovoltaic application[J]. IEEE Transactions on Energy Conversion, 2010, 25(1): 140-147.
[30] J. Rodriguez, J. S. Lai, F. Z. Peng. Multilevel Inverters: A Survey of Topologies, Control, and Applications[J]. IEEE On Industrial Electronics, 2002, 49(4): 724-738.
[31] 2011年中国及海外太阳能光伏产业发展报告[R/OL]. http:// wenku. baidu. com/ view/ e72a45f9941ea76e58fa04d1.html.
[32]赵玉文.我国太阳能光伏产业发展形势和思考[J].世界科技研究和发展, 2003, 25(4): 31-38.
[33]赵玉文. 21世纪我国太阳能利用发展趋势[J].中国电力, 2000, 33(9): 73-77.
[34] Les Bowtell, Tony Ahfock. Comparison Between Unipolar and Bipolar Single Phase Grid-connected Inverters for PV Applications[C]. Australasian Universities Power Engineering Conference, 2007: 1-5.
[35] Timothy CY Wang, Zhihong Ye, Gautam Sinha, Xiaoming Yuan. Output Filter Design for a Grid-interconnected Three-Phase Inverter[C]. IEEE PESC’03. 2003: 779-784.
[36] M. Liserre, F. Blaabjerg, S. Hansen. Design and Control of an LCL-filter based Three-phase Active Rectifier[J]. IEEE Transactions on Industry Applications. 2005, 9: 1281~1291.
[37]刘飞,查晓明,段善旭.三相并网逆变器LCL滤波器的参数设计与研究[J].电工技术学报. 2010, 3: 110-115.
[38]王要强,吴凤江,孙力,孙奎.阻尼损耗最小化的LCL滤波器参数优化设计[J].中国电机工程学报, 2010, 30(27): 90-95.
[39]郭伟峰,徐殿国,武健,王立国. LCL有源电力滤波器新型控制方法[J].中国电机工程学报, 2010, 30(3): 42-48.
[40] S. B. Kjaer. Design and Control of an inverter for Photovoltaic Applications[D]. Ph.D. dissertation, Aalborg University, 2005.
[41]赵清林,郭小强,邬伟扬.单相逆变器并网控制技术研究[J].中国电机工程学报, 2007, 27(16): 60-64.
[42]冯玉,刘强,郭珂,黄剑,周林.单相光伏并网逆变器建模与控制技术研究[C].第四届中国高校电力电子及电力传动学术年会论文集, 2007: 529-536.
[43] R. Teodorescu, F. Blaabjerg, U. Borup, M. Liserre. A New Structure for Grid-connected LCL PV Inverters With Zero Steady-State Error ans Selective Harmonic Compensation[C]. Applied Power Electronics Conference and Exposition, APEC’04, 19th Annual IEEE, 2004, 1:580-581.
[44] Xiaoming Yuan, W. Merk, H. Stemmler, et al. Stationary-Frame Generalized Integrators for Current Control of Active Power Filters With Zero Steady-State Error for Current Harmonics of Concern Under Unbalanced and Distorted Operating Conditions[J]. IEEE Transactions On Industry Applications, 2002, 38(2): 523-532.
[45]夏德钤,翁贻方.自动控制理论[M].北京:机械工业出版社, 2004: 190.
[46] Trishan Esram, Patrick L. Chapman. Comparison of Photovoltaic Array Maximum Power Point Tracking Techniques[J]. IEEE Transactions on Energy Conversion, 2007, 22(2): 439-449.
[47] Weidong Xiao, William G. Dunford. A Modified Adaptive Hill Climbing MPPT Method for Photovoltaic Power Systems[C]. IEEE Power Electronics Specialists Conference, 2004: 1957-1963.