感性电网阻抗下三相光伏逆变器稳定性分析
|
摘要
许多情况下,电网并非理想的电压源,而是存在感性阻抗的弱电网。传统的光伏逆变器设计并没有考虑电网阻抗的影响,逆变器?电网级联系统阻抗不匹配容易导致逆变器的稳定性能降低,甚至不稳定。该文从阻抗的角度,分析L滤波和LCL滤波的光伏逆变器在感性电网阻抗下的稳定性,并分别对稳定判据和输出导纳模型展开研究。通过模型降阶和矩阵近似,简化广义奈奎斯特稳定判据对逆变器?电网级联系统的稳定性分析。借鉴直流电源导纳模型建立的方法,简化由闭环状态矩阵推导d轴输出导纳的计算过程。最后根据所提出的简化判据和建立的d轴输出导纳模型,分析两种滤波方式下级联系统的稳定性,并研究滤波器参数与对级联系统稳定裕度的影响。通过实验对所进行的稳定性分析进行了验证。
In many cases, the grid is not ideal voltage source but a weak grid which contains inductive grid impedance. The influence of grid impedance is not considered in the conventional design of photovoltaic(PV) inverters. Impedance mismatch is likely to deteriorate the stability of the cascaded system of PV inverter and grid, even making the system unstable. From the perspective of the impedance, this paper analyzed the stability of PV inverter with L-filter and LCL-filter under the condition of inductive grid impedance, and the stability criterion and output admittance model were researched respectively. Through the model order reduction and matrix approximating, the stability analysis of inverter cascaded with grid which was usually complemented based on the generalized Nyquist stability criterion(GNC) is simplified. Drawing on the method in which the admittance models of the DC power are built, the calculation process of the d channel output admittance which was usually derived from the closed-loop state matrices is simplified. According to the proposed simplified criterion and the established d channel output admittance model, the stability of PV inverter cascaded with grid was analyzed, and the influence of filter parameters on stability margin of the cascaded system was studied. Experimental results validate the proposed theoretical stability analysis.
In many cases, the grid is not ideal voltage source but a weak grid which contains inductive grid impedance. The influence of grid impedance is not considered in the conventional design of photovoltaic(PV) inverters. Impedance mismatch is likely to deteriorate the stability of the cascaded system of PV inverter and grid, even making the system unstable. From the perspective of the impedance, this paper analyzed the stability of PV inverter with L-filter and LCL-filter under the condition of inductive grid impedance, and the stability criterion and output admittance model were researched respectively. Through the model order reduction and matrix approximating, the stability analysis of inverter cascaded with grid which was usually complemented based on the generalized Nyquist stability criterion(GNC) is simplified. Drawing on the method in which the admittance models of the DC power are built, the calculation process of the d channel output admittance which was usually derived from the closed-loop state matrices is simplified. According to the proposed simplified criterion and the established d channel output admittance model, the stability of PV inverter cascaded with grid was analyzed, and the influence of filter parameters on stability margin of the cascaded system was studied. Experimental results validate the proposed theoretical stability analysis.
引文
[1]张兴,张崇巍.PWM整流器及其控制[M].北京:机械工业出版社,2012:254-255.Zhang Xing,Zhang Chongwei.PWM rectifier and its control[M].Beijing:China Machine Press,2012:254-255(in Chinese).
[2]孙蔚,伍小杰,戴鹏,等.基于LCL滤波器的电压源型PWM整流器控制策略综述[J].电工技术学报,2008,23(1):90-96.Sun Wei,Wu Xiaojie,Dai Peng,et al.An overview of current control strategy for three-phase voltage-source rectifier with LCL-filter[J].Transactions of China Electrotechnical society,2008,23(1):90-96(in Chinese).
[3]谢少军,许津铭.LCL滤波的并网逆变器的电流控制技术研究综述[J].电源学报,2012(4):1-6.Xie Shaojun,Xu Jinming.Overview of current control strategy for grid-tied inverters with LCL filters[J].Journal of Power Supply,2012(4):1-6(in Chinese).
[4]刘韬,郝翔,杨旭,等.LCL滤波的三相并网逆变器电流双环控制策略[J].电源学报,2012(4):7-12.Liu Tao,Hao Xiang,Yang Xu,et al.Current dual-loop control strategy for three-phase grid-connected VSI with LCL filter[J].Journal of Power Supply,2012(4):7-12(in Chinese).
[5]Langkowski H,Do Thanh T,Dettmann K,et al.Grid impedance determination–relevancy for grid integration of renewable energy systems[C]//35th Annual Conference of IEEE on Industrial Electronics.Porto:IEEE,2009:516-521.
[6]Liserre M,Teodorescu R,Blaabjerg F.Stability of photovoltaic and wind turbine grid-connected inverters for a large set of grid impedance values[J].IEEE Transaction on Power Electronics,2006,21(1):263-272.
[7]Chen X,Gong C,Wang H,et al.Stability analysis of LCL-type grid-connected inverter in weak grid systems[C]//2012 International Conference on Renewable Energy Research and Applications.Nagasaki:IEEE,2012:1-6.
[8]Feng X,Ye Z,Xing K,et al.Individual load impedance specification for a stable DC distributed power system[C]//Applied Power Electronics Conference and Exposition.Dallas:IEEE,1999:923-929.
[9]朱成花,严仰光.一种改进的阻抗比判据[J].南京航空航天大学学报,2006,38(3):315-320.Zhu Chenghua,Yan Yangguang.Improved impedance criterion[J].Journal of Nanjing University of Aeronautics&Astronautics,2006,38(3):315-320(in Chinese).
[10]佟强,张东来,徐殿国.分布式电源系统中变换器的输出阻抗与稳定性分析[J].中国电机工程学报,2011,31(12):57-64.Tong Qiang,Zhang Donglai,Xu Dianguo.Output impedance and stability analysis of converters in distributed power systems[J].Proceedings of the CSEE,2011,31(12):57-64(in Chinese).
[11]Sudhoff S,Glover S,Lamm P,et al.Admittance space stability analysis of power electronic systems[J].IEEE Transaction on Aerospace and Electronic Systems,2000,36(3):965-973.
[12]Jiang S,Wang W,Miao F,et al.Research on Admittance Specification Stability of Microgrid at Autonomous mode[C]//7th International Power Electronics and Motion Control Conference.Harbin:IEEE,2012:2090-2094..
[13]Sun J.Impedance-based stability criterion for gridconnected inverters[J].IEEE Transaction on Power Electronics,2011,26(11):3075-3078.
[14]Hiti S,Vlatokovic V,Boroyevich D,et al.A new control algorithm for three-phase PWM buck rectifier with input displacement factor compensation[J].IEEE Transaction on Power Electronics,1994,2(2):173-180.
[15]Belkhayat M.Stability criteria for ac power systems with regulated loads[D].USA:Purdue University,1997.
[16]MacFarlane A,Postlethwaite I.The generalized Nyquist stability criterion and multivariable loci[J].International Journal of Control,1977(25):81-127.
[17]刘增,刘进军.带变流器负载的三相交流电源系统稳定性判据的研究[J].中国电机工程学报,2012,32(25):143-148.Liu Zeng,Liu Jinjun.Stability criterion for three-phase AC power systems with converter load[J].Proceedings of the CSEE,2012,32(25):143-148(in Chinese).
[18]Abe S,Hirokawa M,Ninomiya T.Output impedance design consideration of three control schemes for bus converter in on-board distributed power system[C]//7th International Conference on Power Electronics and Drive Systems.Bangkok:IEEE,2007:1199-1204.
[19]李芬,邹旭东,邹云屏,等.并网LCL滤波的PWM整流器输入阻抗分析[J].电工技术学报,2010,25(1):97-103.Li Fen,Zou Xudong,Zou Yunping,et al.Input impedance analysis of LCL-Filter PWM rectifier connected to grid[J].Transactions of China Electrotechnical society,2010,25(1):97-103(in Chinese).
[20]Familiant Y,Huang J,Corzine K,et al.New techniques for measuring impedance characteristics of three-phase AC power systems[J].IEEE Transaction on Power Electronics,2009,24(7):1802-1810.
[21]Huang J,Corzine K,Belkhayat M.Small-signal impedance measurement of power-electronics-based AC power systems using line-to-ling current injection[J].IEEE Transaction on Power Electronics,2009,24(2):445-455.
[22]吴涛,阮新波.分布式供电系统中负载变换器的输入阻抗分析[J].中国电机工程学报,2008,28(12):20-25.Wu Tao,Ruan Xinbo.Input Impedance analysis of load converters in the distributed power system[J].Proceedings of the CSEE,2008,28(12):20-25(in Chinese).
[23]吴涛,阮新波.分布式供电系统中源变换器输出阻抗的研究[J].中国电机工程学报,2008,28(3):66-72.Wu Tao,Ruan Xinbo.Output impedance analysis of source converters in the DC distributed power system[J].Proceedings of the CSEE,2008,28(3):66-72(in Chinese).
[24]王建华,张方华,龚春英,等.电压控制型Buck DC/DC变换器输出阻抗优化设计[J].电工技术学报,2007,22(8):18-23.Wang Jianhua,Zhang Fanghua,Gong Chunying,et al.Study of output impedance optimization for voltage mode control buck DC/DC converter[J].Transactions of China Electrotechnical society,2007,22(8):18-23(in Chinese).
[25]Ahmadi R,Paschedag D,Ferdowsi M.Closed-loop input and output impedance of DC-DC switching converters operating in voltage and current mode control[C]//IECON2010-36th Annual Conference on IEEE Industrial Electronics Society.Glendale:IEEE,2010:2311-2316.
[26]Sun J.Small-Signal Methods for AC Distributed Power Systems-A Review[J].IEEE Transaction on Power Electronics,2009,24(11):2545-2554.
[27]Figueres E,Garcera G,Sandia J,et al.Sensitivity study of the dynamics of three-phase photovoltaic inverters with an LCL grid filter[J].IEEE Transaction on Industrial Electronics,2009,56(3):706-717.
[28]Cespedes M,Sun J.Renewable energy systems instability involving grid-parallel inverters[C]//Applied Power Electronics Conference and Exposition.Washington:IEEE,2009:1971-1977.
[29]Xu D,Wang F,Ruan Y,et al.Output impedance modeling of grid-connected inverters considering nonlinear effects[C]//2012 IEEE 13th Workshop on Control and Modeling for Power Electronics.Kyoto:IEEE,2012:1-7.
[2]孙蔚,伍小杰,戴鹏,等.基于LCL滤波器的电压源型PWM整流器控制策略综述[J].电工技术学报,2008,23(1):90-96.Sun Wei,Wu Xiaojie,Dai Peng,et al.An overview of current control strategy for three-phase voltage-source rectifier with LCL-filter[J].Transactions of China Electrotechnical society,2008,23(1):90-96(in Chinese).
[3]谢少军,许津铭.LCL滤波的并网逆变器的电流控制技术研究综述[J].电源学报,2012(4):1-6.Xie Shaojun,Xu Jinming.Overview of current control strategy for grid-tied inverters with LCL filters[J].Journal of Power Supply,2012(4):1-6(in Chinese).
[4]刘韬,郝翔,杨旭,等.LCL滤波的三相并网逆变器电流双环控制策略[J].电源学报,2012(4):7-12.Liu Tao,Hao Xiang,Yang Xu,et al.Current dual-loop control strategy for three-phase grid-connected VSI with LCL filter[J].Journal of Power Supply,2012(4):7-12(in Chinese).
[5]Langkowski H,Do Thanh T,Dettmann K,et al.Grid impedance determination–relevancy for grid integration of renewable energy systems[C]//35th Annual Conference of IEEE on Industrial Electronics.Porto:IEEE,2009:516-521.
[6]Liserre M,Teodorescu R,Blaabjerg F.Stability of photovoltaic and wind turbine grid-connected inverters for a large set of grid impedance values[J].IEEE Transaction on Power Electronics,2006,21(1):263-272.
[7]Chen X,Gong C,Wang H,et al.Stability analysis of LCL-type grid-connected inverter in weak grid systems[C]//2012 International Conference on Renewable Energy Research and Applications.Nagasaki:IEEE,2012:1-6.
[8]Feng X,Ye Z,Xing K,et al.Individual load impedance specification for a stable DC distributed power system[C]//Applied Power Electronics Conference and Exposition.Dallas:IEEE,1999:923-929.
[9]朱成花,严仰光.一种改进的阻抗比判据[J].南京航空航天大学学报,2006,38(3):315-320.Zhu Chenghua,Yan Yangguang.Improved impedance criterion[J].Journal of Nanjing University of Aeronautics&Astronautics,2006,38(3):315-320(in Chinese).
[10]佟强,张东来,徐殿国.分布式电源系统中变换器的输出阻抗与稳定性分析[J].中国电机工程学报,2011,31(12):57-64.Tong Qiang,Zhang Donglai,Xu Dianguo.Output impedance and stability analysis of converters in distributed power systems[J].Proceedings of the CSEE,2011,31(12):57-64(in Chinese).
[11]Sudhoff S,Glover S,Lamm P,et al.Admittance space stability analysis of power electronic systems[J].IEEE Transaction on Aerospace and Electronic Systems,2000,36(3):965-973.
[12]Jiang S,Wang W,Miao F,et al.Research on Admittance Specification Stability of Microgrid at Autonomous mode[C]//7th International Power Electronics and Motion Control Conference.Harbin:IEEE,2012:2090-2094..
[13]Sun J.Impedance-based stability criterion for gridconnected inverters[J].IEEE Transaction on Power Electronics,2011,26(11):3075-3078.
[14]Hiti S,Vlatokovic V,Boroyevich D,et al.A new control algorithm for three-phase PWM buck rectifier with input displacement factor compensation[J].IEEE Transaction on Power Electronics,1994,2(2):173-180.
[15]Belkhayat M.Stability criteria for ac power systems with regulated loads[D].USA:Purdue University,1997.
[16]MacFarlane A,Postlethwaite I.The generalized Nyquist stability criterion and multivariable loci[J].International Journal of Control,1977(25):81-127.
[17]刘增,刘进军.带变流器负载的三相交流电源系统稳定性判据的研究[J].中国电机工程学报,2012,32(25):143-148.Liu Zeng,Liu Jinjun.Stability criterion for three-phase AC power systems with converter load[J].Proceedings of the CSEE,2012,32(25):143-148(in Chinese).
[18]Abe S,Hirokawa M,Ninomiya T.Output impedance design consideration of three control schemes for bus converter in on-board distributed power system[C]//7th International Conference on Power Electronics and Drive Systems.Bangkok:IEEE,2007:1199-1204.
[19]李芬,邹旭东,邹云屏,等.并网LCL滤波的PWM整流器输入阻抗分析[J].电工技术学报,2010,25(1):97-103.Li Fen,Zou Xudong,Zou Yunping,et al.Input impedance analysis of LCL-Filter PWM rectifier connected to grid[J].Transactions of China Electrotechnical society,2010,25(1):97-103(in Chinese).
[20]Familiant Y,Huang J,Corzine K,et al.New techniques for measuring impedance characteristics of three-phase AC power systems[J].IEEE Transaction on Power Electronics,2009,24(7):1802-1810.
[21]Huang J,Corzine K,Belkhayat M.Small-signal impedance measurement of power-electronics-based AC power systems using line-to-ling current injection[J].IEEE Transaction on Power Electronics,2009,24(2):445-455.
[22]吴涛,阮新波.分布式供电系统中负载变换器的输入阻抗分析[J].中国电机工程学报,2008,28(12):20-25.Wu Tao,Ruan Xinbo.Input Impedance analysis of load converters in the distributed power system[J].Proceedings of the CSEE,2008,28(12):20-25(in Chinese).
[23]吴涛,阮新波.分布式供电系统中源变换器输出阻抗的研究[J].中国电机工程学报,2008,28(3):66-72.Wu Tao,Ruan Xinbo.Output impedance analysis of source converters in the DC distributed power system[J].Proceedings of the CSEE,2008,28(3):66-72(in Chinese).
[24]王建华,张方华,龚春英,等.电压控制型Buck DC/DC变换器输出阻抗优化设计[J].电工技术学报,2007,22(8):18-23.Wang Jianhua,Zhang Fanghua,Gong Chunying,et al.Study of output impedance optimization for voltage mode control buck DC/DC converter[J].Transactions of China Electrotechnical society,2007,22(8):18-23(in Chinese).
[25]Ahmadi R,Paschedag D,Ferdowsi M.Closed-loop input and output impedance of DC-DC switching converters operating in voltage and current mode control[C]//IECON2010-36th Annual Conference on IEEE Industrial Electronics Society.Glendale:IEEE,2010:2311-2316.
[26]Sun J.Small-Signal Methods for AC Distributed Power Systems-A Review[J].IEEE Transaction on Power Electronics,2009,24(11):2545-2554.
[27]Figueres E,Garcera G,Sandia J,et al.Sensitivity study of the dynamics of three-phase photovoltaic inverters with an LCL grid filter[J].IEEE Transaction on Industrial Electronics,2009,56(3):706-717.
[28]Cespedes M,Sun J.Renewable energy systems instability involving grid-parallel inverters[C]//Applied Power Electronics Conference and Exposition.Washington:IEEE,2009:1971-1977.
[29]Xu D,Wang F,Ruan Y,et al.Output impedance modeling of grid-connected inverters considering nonlinear effects[C]//2012 IEEE 13th Workshop on Control and Modeling for Power Electronics.Kyoto:IEEE,2012:1-7.