LCL并网逆变器双闭环控制策略及其参数设计
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摘要
LCL滤波器广泛应用于并网逆变器中,但弱电网下电网阻抗的波动和数字控制器的延时均可能使逆变器失稳,逆变器侧电流较大的高频谐波也会影响逆变器的使用寿命。本文基于双电流闭环控制的逆变器提出一种完备的参数设计方案。首先建立系统在数字控制下的精确模型,根据劳斯判据确定控制参数的取值范围,然后对有源阻尼特性进行分析从而确定反馈系数K的最佳取值。最后采用系统简化模型计算具体的控制参数,在保证精度的同时降低了计算过程的复杂性。实验结果表明所设计的控制器使并网逆变器具有更好的动态和稳态特性。
LCL filters are widely used in grid-connected inverters, but the inverters might be unstable when connected to a weak grid, and the high THD of the inverter-side current will shorten the life of inverters. Thus this paper proposes a completed parameters design method basing on a dual loop control, which takes the damping characters, digital control delay and resistance of the weak grid into consideration and reduces the THD of inverter-side current effectively. First, the precise model is derived to calculate an approximate range of control parameters. Then the exact value of K is derived by analyzing the damping characters. A simplified model is adopted to reduce the complication of the calculation for the control parameters. The experimental result shows that the grid-connected inverter employing the proposed controler attains both a better dynamic and static performance.
LCL filters are widely used in grid-connected inverters, but the inverters might be unstable when connected to a weak grid, and the high THD of the inverter-side current will shorten the life of inverters. Thus this paper proposes a completed parameters design method basing on a dual loop control, which takes the damping characters, digital control delay and resistance of the weak grid into consideration and reduces the THD of inverter-side current effectively. First, the precise model is derived to calculate an approximate range of control parameters. Then the exact value of K is derived by analyzing the damping characters. A simplified model is adopted to reduce the complication of the calculation for the control parameters. The experimental result shows that the grid-connected inverter employing the proposed controler attains both a better dynamic and static performance.
引文
[1] Kisu Kim, Honnyong Cha, Heung-Geun Kim. A new single-phase switched-coupled-inductor DC-AC inverter for photovoltaic systems[J]. IEEE Transactions on Power Electronics, 2017, 32(7): 5016-5022.
[2] 程谆,张阳,邓木生(Cheng Chun, Zhang Yang, Deng Musheng). 基于阻抗源逆变器的永磁直驱风力发电变流系统综述(Review of permanent magnet direct drive wind power conversion system with impedance-source inverter)[J]. 电工电能新技术(Advanced Technology of Electrical Engineering and Energy),2018,10.12067/ATEEE1801056.
[3] 王晓寰,张敏霞,张纯江,等(Wang Xiaohuan, Zhang Minxia, Zhang Chunjiang, et al.). 基于自适应下垂控制的多机逆变器双模式运行及平滑切换研究(Study on two-modes operation and seamless transfer of multi-inverter based on adaptive droop control strategy)[J]. 电工电能新技术(Advanced Technology of Electrical Engineering and Energy),2018,37(3):17-25.
[4] 谷青发,王杰(Gu Qingfa, Wang Jie). 逆变型微网下垂控制器参数选择和稳定性分析(Droop controller parameter selection and stability analysis for inverter-interfaced microgrid)[J]. 电工电能新技术(Advanced Technology of Electrical Engineering and Energy),2017,36(7):34-40.
[5] Beres R N, Wang X, Liserre M, et al. A review of passive power filters for three-phase grid-connected volt-age-source converters[J]. IEEE Journal of Emerging & Selected Topics in Power Electronics, 2016, 4(1): 54-69.
[6] 许晓笛,李子欣,楚遵方,等(Xu Xiaodi, Li Zixin, Chu Zunfang, et al.). 三相四线三电平APF并联运行有源阻尼方法(Active damping method of three-phase four-wire three-level multi-APF system)[J]. 电工电能新技术(Advanced Technology of Electrical Engineering and Energy),2017,36(7):12-19.
[7] Wang B, Xu Y, Shen Z, et al. Current control of grid-connected inverter with LCL filter based on extended-state observer estimations using single sensor and achieving improved robust observation dynamics[J]. IEEE Transactions on Industrial Electronics, 2017, 64(7): 5428-5439.
[8] Zhang S, Jiang S, Lu X, et al. Resonance issues and damping techniques for grid-connected inverters with long transmission cable[J]. IEEE Transactions on Power Electronics, 2014, 29(1): 110-120.
[9] 庄超,叶永强,赵强松,等(Zhuang Chao, Ye Yongqiang, Zhao Qiangsong, et al.). 基于分裂电容法的LCL并网逆变器控制策略分析与改进(Analysis and improvement of the control strategy of LCL grid-connected inverter based on split-capacitor)[J].电工技术学报(Transactions of China Electrotechnical Society),2015,30(16):85-93.
[10] He N, Xu D, Zhu Y, et al. Weighted average current control in a three-phase grid inverter with an LCL filter[J]. IEEE Transactions on Power Electronics, 2013, 28(6): 2785-2797.
[11] Ben Said-Romdhane M, Naouar M W, Slama-Belkhodja I, et al. Robust active damping methods for LCL filter-based grid-connected converters[J]. IEEE Transactions on Power Electronics, 2017, 32(9): 6739-6750.
[12] Perez-Estevez D, Doval-Gandoy J, Yepes A G, et al. En-hanced resonant current controller for grid-connected converters with LCL filter[J]. IEEE Transactions on Power Electronics,2018,33(5):3765-3778.
[13] Yang D, Ruan X, Wu H. Impedance shaping of the grid-connected inverter with LCL filter to improve its adaptability to the weak grid condition[J]. IEEE Transactions on Power Electronics, 2014, 29(11): 5795-5805.
[14] 许津铭,谢少军,肖华锋.(Xu Jinming, Xie Shaojun, Xiao Huafeng).LCL滤波器有源阻尼控制机制研究(Research on control mechanism of active damping for LCL filters)[J]. 中国电机工程学报(Proceedings of the CSEE),2012,32(9):27-33,6.
[15] 潘冬华, 阮新波, 王学华, 等(Pan Donghua, Ruan Xinbo, Wang Xuehua, et al.). 提高LCL型并网逆变器鲁棒性的电容电流即时反馈有源阻尼方法(A capacitor-current real-time feedback active damping method for improving robustness of the LCL-type grid-connected inverter)[J]. 中国电机工程学报(Proceedings of the CSEE), 2013, 33(18):2558-2566.
[16] 鲍陈磊,阮新波,王学华,等(Bao Chenlei, Ruan Xinbo, Wang Xuehua, et al.). 基于PI调节器和电容电流反馈有源阻尼的LCL型并网逆变器闭环参数设计(Design of grid-connected inverters with LCL filter based on pi regulator and capacitor current feedback active damping)[J]. 中国电机工程学报(Proceedings of the CSEE),2012,32(25):133-142.
[17] Erickson R W,Maksimovic D.Fundamentals of power electronics[M].Springer,2001.331-408.
[18] Q/GDW 617-2011,光伏电站接入电网技术规定(Technical rule for photovoltaic power station connected topower grid) [S].
[19] Sahoo A K, Shahani A, Basu K, et al. LCL filter design for grid-connected inverters by analytical estimation of PWM ripple voltage[A].IEEE Applied Power Electronics Conference and Exposition [C]. 2014.1281-1286.
[2] 程谆,张阳,邓木生(Cheng Chun, Zhang Yang, Deng Musheng). 基于阻抗源逆变器的永磁直驱风力发电变流系统综述(Review of permanent magnet direct drive wind power conversion system with impedance-source inverter)[J]. 电工电能新技术(Advanced Technology of Electrical Engineering and Energy),2018,10.12067/ATEEE1801056.
[3] 王晓寰,张敏霞,张纯江,等(Wang Xiaohuan, Zhang Minxia, Zhang Chunjiang, et al.). 基于自适应下垂控制的多机逆变器双模式运行及平滑切换研究(Study on two-modes operation and seamless transfer of multi-inverter based on adaptive droop control strategy)[J]. 电工电能新技术(Advanced Technology of Electrical Engineering and Energy),2018,37(3):17-25.
[4] 谷青发,王杰(Gu Qingfa, Wang Jie). 逆变型微网下垂控制器参数选择和稳定性分析(Droop controller parameter selection and stability analysis for inverter-interfaced microgrid)[J]. 电工电能新技术(Advanced Technology of Electrical Engineering and Energy),2017,36(7):34-40.
[5] Beres R N, Wang X, Liserre M, et al. A review of passive power filters for three-phase grid-connected volt-age-source converters[J]. IEEE Journal of Emerging & Selected Topics in Power Electronics, 2016, 4(1): 54-69.
[6] 许晓笛,李子欣,楚遵方,等(Xu Xiaodi, Li Zixin, Chu Zunfang, et al.). 三相四线三电平APF并联运行有源阻尼方法(Active damping method of three-phase four-wire three-level multi-APF system)[J]. 电工电能新技术(Advanced Technology of Electrical Engineering and Energy),2017,36(7):12-19.
[7] Wang B, Xu Y, Shen Z, et al. Current control of grid-connected inverter with LCL filter based on extended-state observer estimations using single sensor and achieving improved robust observation dynamics[J]. IEEE Transactions on Industrial Electronics, 2017, 64(7): 5428-5439.
[8] Zhang S, Jiang S, Lu X, et al. Resonance issues and damping techniques for grid-connected inverters with long transmission cable[J]. IEEE Transactions on Power Electronics, 2014, 29(1): 110-120.
[9] 庄超,叶永强,赵强松,等(Zhuang Chao, Ye Yongqiang, Zhao Qiangsong, et al.). 基于分裂电容法的LCL并网逆变器控制策略分析与改进(Analysis and improvement of the control strategy of LCL grid-connected inverter based on split-capacitor)[J].电工技术学报(Transactions of China Electrotechnical Society),2015,30(16):85-93.
[10] He N, Xu D, Zhu Y, et al. Weighted average current control in a three-phase grid inverter with an LCL filter[J]. IEEE Transactions on Power Electronics, 2013, 28(6): 2785-2797.
[11] Ben Said-Romdhane M, Naouar M W, Slama-Belkhodja I, et al. Robust active damping methods for LCL filter-based grid-connected converters[J]. IEEE Transactions on Power Electronics, 2017, 32(9): 6739-6750.
[12] Perez-Estevez D, Doval-Gandoy J, Yepes A G, et al. En-hanced resonant current controller for grid-connected converters with LCL filter[J]. IEEE Transactions on Power Electronics,2018,33(5):3765-3778.
[13] Yang D, Ruan X, Wu H. Impedance shaping of the grid-connected inverter with LCL filter to improve its adaptability to the weak grid condition[J]. IEEE Transactions on Power Electronics, 2014, 29(11): 5795-5805.
[14] 许津铭,谢少军,肖华锋.(Xu Jinming, Xie Shaojun, Xiao Huafeng).LCL滤波器有源阻尼控制机制研究(Research on control mechanism of active damping for LCL filters)[J]. 中国电机工程学报(Proceedings of the CSEE),2012,32(9):27-33,6.
[15] 潘冬华, 阮新波, 王学华, 等(Pan Donghua, Ruan Xinbo, Wang Xuehua, et al.). 提高LCL型并网逆变器鲁棒性的电容电流即时反馈有源阻尼方法(A capacitor-current real-time feedback active damping method for improving robustness of the LCL-type grid-connected inverter)[J]. 中国电机工程学报(Proceedings of the CSEE), 2013, 33(18):2558-2566.
[16] 鲍陈磊,阮新波,王学华,等(Bao Chenlei, Ruan Xinbo, Wang Xuehua, et al.). 基于PI调节器和电容电流反馈有源阻尼的LCL型并网逆变器闭环参数设计(Design of grid-connected inverters with LCL filter based on pi regulator and capacitor current feedback active damping)[J]. 中国电机工程学报(Proceedings of the CSEE),2012,32(25):133-142.
[17] Erickson R W,Maksimovic D.Fundamentals of power electronics[M].Springer,2001.331-408.
[18] Q/GDW 617-2011,光伏电站接入电网技术规定(Technical rule for photovoltaic power station connected topower grid) [S].
[19] Sahoo A K, Shahani A, Basu K, et al. LCL filter design for grid-connected inverters by analytical estimation of PWM ripple voltage[A].IEEE Applied Power Electronics Conference and Exposition [C]. 2014.1281-1286.