弱电网条件下基于稳定域和谐波交互的并网逆变器LCL参数设计
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摘要
弱电网下的并网逆变器LCL滤波器谐振频率对于系统稳定性和并网电流质量的影响至关重要。为了选择合适的谐振频率,首先在s域中建立谐振稳定域判据。其次,考虑2个因素对谐振频率设计的影响:一是电网阻抗和滤波器电感的变化,采用基于几何平均法的LCL谐振频率设计方案可以适应这种宽范围变化;二是背景谐波,通过分析多个频率间的交互作用对并网电流的显著影响,推导子稳定域判据,进而得出优选的LCL谐振频率值。其次,结合桥臂侧最大电流纹波方程,建立一种简单且鲁棒性强的LCL滤波器参数计算方案。最后,基于RT-LAB对所提出的LCL参数设计方法进行实验验证,证明理论分析的正确性。
Resonance frequency of the LCL filter for a grid-connected inverter in weak grid is essential for system stability and grid-injected current quality. To select the resonance frequency properly, resonance stability region criterion was established in s domain, then two considerations were taken into account. One is the grid impedance and filter inductance variations, the LCL resonance frequency was designed based on the geometric mean to adapt to this variation in a large range. Another one is the background harmonics, the significant impact on grid-injected current due to the interaction of multi-frequency was analyzed and sub-stability region criterion is derived to determine an optimum value of the LCL resonance frequency. Associated with the invertercurrent maximum current ripple expression, a simple and robust method to calculate LCL filter parameters without external damping was established. Experimental results based on RT-LAB were provided to validate the effectiveness of the proposed LCL design method, which effectively proved the correctness of the theoretical analysis.
Resonance frequency of the LCL filter for a grid-connected inverter in weak grid is essential for system stability and grid-injected current quality. To select the resonance frequency properly, resonance stability region criterion was established in s domain, then two considerations were taken into account. One is the grid impedance and filter inductance variations, the LCL resonance frequency was designed based on the geometric mean to adapt to this variation in a large range. Another one is the background harmonics, the significant impact on grid-injected current due to the interaction of multi-frequency was analyzed and sub-stability region criterion is derived to determine an optimum value of the LCL resonance frequency. Associated with the invertercurrent maximum current ripple expression, a simple and robust method to calculate LCL filter parameters without external damping was established. Experimental results based on RT-LAB were provided to validate the effectiveness of the proposed LCL design method, which effectively proved the correctness of the theoretical analysis.
引文
[1]桑顺,高宁,蔡旭,等.功率-电压控制型并网逆变器及其弱电网适应性研究[J].中国电机工程学报,2017,37(8):2339-2350.Sang Shun,Gao Ning,Cai Xu,etal.A Power-voltage controlled grid-connected inverter and its adaptability research under weak grid conditions[J].Proceedings of the CSEE,2017,37(8):2339-2350(in Chinese).
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[3]Yao Wenli,Yang Yongheng,Zhang Xiaobin,et al.Design and analysis of robust active damping for LCL filters using digital notch filters[J].IEEE Transactions on Power Electronics,2017,32(3):2360-2375.
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[7]Wang Xiongfei,Blaabjerg F,Loh P C.Grid-current-feedback active damping for LCL resonance in grid-connected voltage-source converters[J].IEEETransactions on Power Electronics,2016,31(1):213-223.
[8]Pan Donghua,Ruan Xinbo,Bao Chenlei,et al.Capacitor-current-feedback active damping with reduced computation delay for improving robustness of LCL-type grid-connected inverter[J].IEEE Transactions on Power Electronics,2014,29(7):3414-3427.
[9]Li Xiaoqiang,Wu Xiaojie,Geng Yiwen,et al.Wide damping region for LCL-type grid-connected inverter with an improved capacitor-current-feedback method[J].IEEETransactions on Power Electronics,2015,30(9):5247-5259.
[10]Ghoshal A,John V.Active damping of LCL filter at low switching to resonance frequency ratio[J].IET Power Electronics,2015,8(4):574-582.
[11]He Jinwei,Li Yunwei,Bosnjak D,et al.Investigation and active damping of multiple resonances in a parallel-inverter-based microgrid[J].IEEE Transactions on Power Electronics,2013,28(1):234-246.
[12]ParkerS G,Mc Grath B P,Holmes D G.Regions of active damping control for LCL filters[J].IEEE Transactions on Industry Applications,2014,50(1):424-432.
[13]Jayalath S,Hanif M.Generalized LCL-filter design algorithm for grid-connected voltage-source inverter[J].IEEE Transactions on Industrial Electronics,2017,64(3):1905-1915.
[14]TangYi,Yoon C,Zhu Rongwu,et al.Generalized stability regions of current control for LCL-filtered grid-connected converters without passive or active damping[C]//2015IEEE Energy Conversion Congress and Exposition.Montreal,QC,Canada:IEEE,2015:2040-2047.
[15]WangJianguo,Yan Jiudun,Jiang Lin,et al.Delay-dependent stability of single-loop controlled grid-connected inverters with LCL filters[J].IEEETransactions on Power Electronics,2016,31(1):743-757.
[16]Pe?a-Alzola R,Liserre M,Blaabjerg F,et al.LCL-filter design for robust active damping in grid-connected converters[J].IEEE Transactions on Industrial Informatics,2014,10(4):2192-2203.
[17]Liserre M,Blaabjerg F,Hansen S.Design and control of an LCL-filter based three-phase active rectifier[C]//36th IAS Annual Meeting-Conference Record of the 2001Industry Applications Conference.Chicago,IL:IEEE,2001:299-307.
[18]Reznik A,Simoes M G,Al-Durra A,et al.LCL filter design and performance analysis for grid-interconnected systems[J].IEEE Transactions on Industry Applications,2014,50(2):1225-1232.
[19]Wu T F,Misra M,Lin L C,et al.An improved resonant frequency based systematic LCL filter design method for grid-connected inverter[J].IEEE Transactions on Industrial Electronics,2017,64(8):6412-6421.
[20]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 Transactions on Power Electronics,2006,21(1):263-272.
[21]王学华,阮新波,刘尚伟.抑制电网背景谐波影响的并网逆变器控制策略[J].中国电机工程学报,2011,31(6):7-14.Wang Xuehua,Ruan Xinbo,Liu Shangwei.Control strategy for grid-connected inverter to suppress current distortion effected by background harmonics in grid voltage[J].Proceedings of the CSEE,2011,31(6):7-14(in Chinese).
[22]Liu Fang,Zhang Jie,Xu Haizhen,et al.LCL filter design based on non-minimum-phase stability region for grid-connected inverters in weak grid[C]//2017 IEEEEnergy Conversion Congress and Exposition(ECCE).Cincinnati,OH,USA:IEEE,2017:4978-4982.
[23]Huang Min,Wang Xiongfei,Loh P C,et al.LLCL-filtered grid converter with improved stability and robustness[J].IEEE Transactions on Power Electronics,2016,31(5):3958-3967.
[24]Odavic M,Sumner M,Zanchetta P,et al.A theoretical analysis of the harmonic content of PWM waveforms for multiple-frequency modulators[J].IEEE Transactions on Power Electronics,2010,25(1):131-141.
[25]Holmes D G.A general analytical method for determining the theoretical harmonic components of carrier based PWM strategies[C]//Conference Record of 1998 IEEEIndustry Applications Conference.23rd IAS Annual Meeting.St.Louis,MO,USA:IEEE,1998:1207-1214.
[26]Holmes D G,Lipo T A.Pulse width modulation for power converters:Principles and practice[M].USA:Wiley-IEEEPress,2003:215-257.
[27]GabeI J,Montagner V F,Pinheiro H.Design and implementation of a robust current controller for VSIconnected to the grid through an LCL filter[J].IEEETransactions on Power Electronics,2009,24(6):1444-1452.
[28]Cardenas V M.Digital control in power electronics[C]//IEEE International Power Electronics Congress.Puebla,Mexico:IEEE,2006.
[29]Rodriguez P,Pou J,Bergas J,et al.Decoupled double synchronous reference frame PLL for power converters control[J].IEEE Transactions on Power Electronics,2007,22(2):584-592.
[30]Van de Sype D M,De Gusseme K,De Belie F M L L,et al.Small-signal z-domain analysis of digitally controlled converters[J].IEEE Transactions on Power Electronics,2006,21(2):470-478.
[31]Zhang Xiaotian,Spencer J W,Guerrero J M.Small-signal modeling of digitally controlled grid-connected inverters with LCL filters[J].IEEE Transactions on Industrial Electronics,2013,60(9):3752-3765.
[32]许津铭,季林,葛小伟,等.计及逆变器侧电流反馈影响的LCL滤波器参数优化设计[J].中国电机工程学报,2016,36(17):4656-4664.Xu Jinming,Ji Lin,Ge Xiaowei,et al.LCL-filter optimization design with consideration of inverter-side current feedback control impacts[J].Proceedings of the CSEE,2016,36(17):4656-4664(in Chinese).
[33]Gullvik W,Norum L,Nilsen R.Active damping of resonance oscillations in LCL-filters based on virtual flux and virtual resistor[C]//European Conference on Power Electronics and Applications.Aalborg,Denmark:IEEE,2007:1-10.
[34]阮新波,王学华,潘冬华,等.LCL型并网逆变器的控制技术[M].北京:科学出版社,2015:33-103.Ruan Xinbo,Wang Xuehua,Pan Donghua,et al.Control techniques for LCL-type grid-connected inverters[M].Beijing:Science Press,2015:33-103(in Chinese).
[35]Akagi H,Watanabe E H,Aredes M.Instantaneous power theory and applications to power conditioning[M].USA:IEEE Press,2007:41-108.
[36]Jiao Yang,Lee F C.LCL filter design and inductor current ripple analysis for a three-level NPC grid interface converter[J].IEEE Transactions on Power Electronics,2015,30(9):4659-4668.
[2]潘冬华,阮新波,王学华,等.增强LCL型并网逆变器对电网阻抗鲁棒性的控制参数设计[J].中国电机工程学报,2015,35(10):2558-2566.Pan Donghua,Ruan Xinbo,Wang Xuehua,etal.Controller design for LCL-type grid-connected inverter to achieve high robustness against grid-impedance variation[J].Proceedings of the CSEE,2015,35(10):2558-2566(in Chinese).
[3]Yao Wenli,Yang Yongheng,Zhang Xiaobin,et al.Design and analysis of robust active damping for LCL filters using digital notch filters[J].IEEE Transactions on Power Electronics,2017,32(3):2360-2375.
[4]Beres R N,Wang X F,Liserre M,et al.A review of passive power filters for three-phase grid-connected voltage-source converters[J].IEEE Journal of Emerging&Selected Topics in Power Electronics,2016,4(1):54-69.
[5]Beres R N,Wang Xiongfei,Blaabjerg F,et al.Optimal design of high-order passive-damped filters for grid-connected applications[J].IEEE Transactions on Power Electronics,2016,31(3):2083-2098.
[6]Pe?a-Alzola R,Liserre M,Blaabjerg F,et al.Analysis of the passive damping losses in LCL-filter-based grid converters[J].IEEE Transactions on Power Electronics,2013,28(6):2642-2646.
[7]Wang Xiongfei,Blaabjerg F,Loh P C.Grid-current-feedback active damping for LCL resonance in grid-connected voltage-source converters[J].IEEETransactions on Power Electronics,2016,31(1):213-223.
[8]Pan Donghua,Ruan Xinbo,Bao Chenlei,et al.Capacitor-current-feedback active damping with reduced computation delay for improving robustness of LCL-type grid-connected inverter[J].IEEE Transactions on Power Electronics,2014,29(7):3414-3427.
[9]Li Xiaoqiang,Wu Xiaojie,Geng Yiwen,et al.Wide damping region for LCL-type grid-connected inverter with an improved capacitor-current-feedback method[J].IEEETransactions on Power Electronics,2015,30(9):5247-5259.
[10]Ghoshal A,John V.Active damping of LCL filter at low switching to resonance frequency ratio[J].IET Power Electronics,2015,8(4):574-582.
[11]He Jinwei,Li Yunwei,Bosnjak D,et al.Investigation and active damping of multiple resonances in a parallel-inverter-based microgrid[J].IEEE Transactions on Power Electronics,2013,28(1):234-246.
[12]ParkerS G,Mc Grath B P,Holmes D G.Regions of active damping control for LCL filters[J].IEEE Transactions on Industry Applications,2014,50(1):424-432.
[13]Jayalath S,Hanif M.Generalized LCL-filter design algorithm for grid-connected voltage-source inverter[J].IEEE Transactions on Industrial Electronics,2017,64(3):1905-1915.
[14]TangYi,Yoon C,Zhu Rongwu,et al.Generalized stability regions of current control for LCL-filtered grid-connected converters without passive or active damping[C]//2015IEEE Energy Conversion Congress and Exposition.Montreal,QC,Canada:IEEE,2015:2040-2047.
[15]WangJianguo,Yan Jiudun,Jiang Lin,et al.Delay-dependent stability of single-loop controlled grid-connected inverters with LCL filters[J].IEEETransactions on Power Electronics,2016,31(1):743-757.
[16]Pe?a-Alzola R,Liserre M,Blaabjerg F,et al.LCL-filter design for robust active damping in grid-connected converters[J].IEEE Transactions on Industrial Informatics,2014,10(4):2192-2203.
[17]Liserre M,Blaabjerg F,Hansen S.Design and control of an LCL-filter based three-phase active rectifier[C]//36th IAS Annual Meeting-Conference Record of the 2001Industry Applications Conference.Chicago,IL:IEEE,2001:299-307.
[18]Reznik A,Simoes M G,Al-Durra A,et al.LCL filter design and performance analysis for grid-interconnected systems[J].IEEE Transactions on Industry Applications,2014,50(2):1225-1232.
[19]Wu T F,Misra M,Lin L C,et al.An improved resonant frequency based systematic LCL filter design method for grid-connected inverter[J].IEEE Transactions on Industrial Electronics,2017,64(8):6412-6421.
[20]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 Transactions on Power Electronics,2006,21(1):263-272.
[21]王学华,阮新波,刘尚伟.抑制电网背景谐波影响的并网逆变器控制策略[J].中国电机工程学报,2011,31(6):7-14.Wang Xuehua,Ruan Xinbo,Liu Shangwei.Control strategy for grid-connected inverter to suppress current distortion effected by background harmonics in grid voltage[J].Proceedings of the CSEE,2011,31(6):7-14(in Chinese).
[22]Liu Fang,Zhang Jie,Xu Haizhen,et al.LCL filter design based on non-minimum-phase stability region for grid-connected inverters in weak grid[C]//2017 IEEEEnergy Conversion Congress and Exposition(ECCE).Cincinnati,OH,USA:IEEE,2017:4978-4982.
[23]Huang Min,Wang Xiongfei,Loh P C,et al.LLCL-filtered grid converter with improved stability and robustness[J].IEEE Transactions on Power Electronics,2016,31(5):3958-3967.
[24]Odavic M,Sumner M,Zanchetta P,et al.A theoretical analysis of the harmonic content of PWM waveforms for multiple-frequency modulators[J].IEEE Transactions on Power Electronics,2010,25(1):131-141.
[25]Holmes D G.A general analytical method for determining the theoretical harmonic components of carrier based PWM strategies[C]//Conference Record of 1998 IEEEIndustry Applications Conference.23rd IAS Annual Meeting.St.Louis,MO,USA:IEEE,1998:1207-1214.
[26]Holmes D G,Lipo T A.Pulse width modulation for power converters:Principles and practice[M].USA:Wiley-IEEEPress,2003:215-257.
[27]GabeI J,Montagner V F,Pinheiro H.Design and implementation of a robust current controller for VSIconnected to the grid through an LCL filter[J].IEEETransactions on Power Electronics,2009,24(6):1444-1452.
[28]Cardenas V M.Digital control in power electronics[C]//IEEE International Power Electronics Congress.Puebla,Mexico:IEEE,2006.
[29]Rodriguez P,Pou J,Bergas J,et al.Decoupled double synchronous reference frame PLL for power converters control[J].IEEE Transactions on Power Electronics,2007,22(2):584-592.
[30]Van de Sype D M,De Gusseme K,De Belie F M L L,et al.Small-signal z-domain analysis of digitally controlled converters[J].IEEE Transactions on Power Electronics,2006,21(2):470-478.
[31]Zhang Xiaotian,Spencer J W,Guerrero J M.Small-signal modeling of digitally controlled grid-connected inverters with LCL filters[J].IEEE Transactions on Industrial Electronics,2013,60(9):3752-3765.
[32]许津铭,季林,葛小伟,等.计及逆变器侧电流反馈影响的LCL滤波器参数优化设计[J].中国电机工程学报,2016,36(17):4656-4664.Xu Jinming,Ji Lin,Ge Xiaowei,et al.LCL-filter optimization design with consideration of inverter-side current feedback control impacts[J].Proceedings of the CSEE,2016,36(17):4656-4664(in Chinese).
[33]Gullvik W,Norum L,Nilsen R.Active damping of resonance oscillations in LCL-filters based on virtual flux and virtual resistor[C]//European Conference on Power Electronics and Applications.Aalborg,Denmark:IEEE,2007:1-10.
[34]阮新波,王学华,潘冬华,等.LCL型并网逆变器的控制技术[M].北京:科学出版社,2015:33-103.Ruan Xinbo,Wang Xuehua,Pan Donghua,et al.Control techniques for LCL-type grid-connected inverters[M].Beijing:Science Press,2015:33-103(in Chinese).
[35]Akagi H,Watanabe E H,Aredes M.Instantaneous power theory and applications to power conditioning[M].USA:IEEE Press,2007:41-108.
[36]Jiao Yang,Lee F C.LCL filter design and inductor current ripple analysis for a three-level NPC grid interface converter[J].IEEE Transactions on Power Electronics,2015,30(9):4659-4668.