基于输入/输出线性化的准Z源逆变器光伏并网控制策略
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摘要
应用于光伏系统的准Z源逆变器(QZSI)存在着不稳定的零动态和非线性特性,导致系统振荡、动态响应缓慢和控制器设计复杂等问题。基于输入/输出反馈线性化方法,提出将直通电流和脉冲直流电压作为状态变量建立QZSI直流侧的仿射非线性二阶模型,将原非线性系统转化为线性系统,具有模型精确、阶数低、算法简单等优点。基于此模型,设计经典PI控制器调节QZSI的输入电压,并最终实现最大功率点跟踪(MPPT)。阐述了QZSI的输入/输出线性化建模方法,并通过理论推导证明该线性化系统零动态稳定,设计QZSI直流侧与交流侧控制器,实现光伏逆变器升压、并网波形及功率控制3个目标。通过仿真及实验与经典控制策略对比,显示该控制方法能使QZSI输入电压快速跟踪最大功率点,并且在系统工作点大范围变化时能保证输入电压及并网电流波形质量。
The quasi-Z-source inverter(QZSI) applied to the photovoltaic(PV) system has nonlinear and unstable zero dynamic characteristics, which leads to the problem of system oscillation, slow dynamic response and complex controller design. Thereby, we propose a nonlinear control strategy based on Input-output Linearization for QZSI. The affine nonlinear model of the QZSI DC-side is presented and transformed to a linearized form with the help of input-output feedback linearization technique. Based on the linearized system, simple linear controllers are employed to regulate the input voltage of the QZSI, and finally achieve maximum power point tracking. Moreover, the input/output linearization modeling method for the quasi Z-source inverter is described. The zero dynamic stability of the linearized system is proved by theoretical deduction. The DC-side and AC-side controller of the quasi Z-source inverter are designed to realize the three targets of boosting the PV inverter and controlling the grid-connected waveform and the power. Through simulation and experiment, compared with classical control strategy, it is shown that this control method can make QZSI input voltage to track the maximum power point fast, and guarantee the quality of input voltage and grid-connected current waveform when the operation point of the system changes in a wide range.
The quasi-Z-source inverter(QZSI) applied to the photovoltaic(PV) system has nonlinear and unstable zero dynamic characteristics, which leads to the problem of system oscillation, slow dynamic response and complex controller design. Thereby, we propose a nonlinear control strategy based on Input-output Linearization for QZSI. The affine nonlinear model of the QZSI DC-side is presented and transformed to a linearized form with the help of input-output feedback linearization technique. Based on the linearized system, simple linear controllers are employed to regulate the input voltage of the QZSI, and finally achieve maximum power point tracking. Moreover, the input/output linearization modeling method for the quasi Z-source inverter is described. The zero dynamic stability of the linearized system is proved by theoretical deduction. The DC-side and AC-side controller of the quasi Z-source inverter are designed to realize the three targets of boosting the PV inverter and controlling the grid-connected waveform and the power. Through simulation and experiment, compared with classical control strategy, it is shown that this control method can make QZSI input voltage to track the maximum power point fast, and guarantee the quality of input voltage and grid-connected current waveform when the operation point of the system changes in a wide range.
引文
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[3]王晓刚,张杰.基于开关电感的增强型Z源三电平逆变器[J].电力系统保护与控制,2015,43(16):65-72.WANG Xiaogang,ZHANG Jie.Enhanced Z-source three-level inverter based on switched-inductor[J].Power System Protection and Control,2015,43(16):65-72.
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[9]李媛,彭方正.Z源/准Z源逆变器在光伏并网系统中的电容电压恒压控制策略[J].电工技术学报,2011,26(5):62-69.LI Yuan,PENG Fangzheng.Constant capacitor voltage control strategy for Z-source/quasi-Z-source inverter in grid-connected photovoltaic systems[J].Transactions of China Electro technical Society,2011,26(5):62-69.
[10]陈宗祥,蒋赢,潘俊民,等.基于滑模控制的Z源逆变器在单相光伏系统中的应用[J].中国电机工程学报,2008,28(21):33-39.CHEN Zongxiang,JIANG Ying,PAN Junmin,et al.A Z-source inverter for a single-phase PV system based on sliding-mode control[J].Proceedings of the CSEE,2008,28(21):33-39.
[11]郑建勇,刘孝辉.Z源光伏并网逆变器无差拍解耦控制[J].电网技术,2012,36(3):252-256.ZHENG Jianyong,LIU Xiaohui.Deadbeat decoupling control of Z-source grid-connected inverter[J].Power System Technology,2012,36(3):252-256.
[12]LIU Y,GE B,ABU-RUB H,et al.Model predictive direct power control for active power decoupled single phase quasi-Z-source inverter[J].IEEE Transactions on Industrial Informatics,2016,12(4):1550-1559.
[13]丁新平,钱照明,崔彬,等.基于模糊PID的Z源逆变器直流链升压电路控制[J].中国电机工程学报,2008,28(24):31-38.DING Xinping,QIAN Zhaoming,CUI Bin,et al.Fuzzy PID controller for DC-link boost voltage in Z-source inverter[J].Proceedings of the CSEE,2008,28(24):31-38.
[14]薛阳,李华郁,阚东跃,等.基于反馈线性化鲁棒控制μ方法的准开关升压型逆变器光伏并网策略[J].电力系统保护与控制,2017,45(1):47-52.XUE Yang,LI Huayu,KAN Dongyue,et al.Research on grid-connected control for the quasi-switched boost inverter of photovoltaic system based on feedback linearization andμ-synthesis method[J].Power System Protection and Control,2017,45(1):47-52.
[15]潘月斗,陈继义,徐杰,等.矩阵变换器输入电流的状态反馈线性化控制[J].高电压技术,2014,40(8):2497-2503.PAN Yuedou,CHEN Jiyi,XU Jie,et al.State feedback linearization control for current of input side in the matrix convertor[J].High Voltage Engineering,2014,40(8):2497-2503.
[16]GONG H,LI Y,WANG Y,et al.Input-output feedback linearization based control for quasi-Z-source inverter in photovoltaic application[C]∥2016 IEEE Energy Conversion Congress and Exposition.Milwaukee,WI,USA:IEEE,2016.
[17]FANG F,LI Y,ZHANG R,et al.An nonlinear control strategy for single phase quasi Z-source grid-connected inverter[C]∥IECON2017-43rd Annual Conference of the IEEE Industrial Electronics Society.Beijing,China:IEEE,2017.
[18]PAN D,RUAN X,BAO C,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.
[19]AYAD A,HASHEM M,HACKL C,et al.Proportional-resonant controller design for quasi-Z-source inverters with LC fil-ters[C]∥42nd Annual Conference of the IEEE Industrial Electronics Society.Florence,Italy:IEEE,2016.
[2]李长云,张超,张迎春.Z-源/准Z-源逆变器拓扑的演绎机理[J].高电压技术,2016,42(7):2111-2118.LI Changyun,ZHANG Chao,ZHANG Yingchun.Evolution mechanism of Z-source/quasi-Z-source inverter topologies[J].High Voltage Engineering,2016,42(7):2111-2118.
[3]王晓刚,张杰.基于开关电感的增强型Z源三电平逆变器[J].电力系统保护与控制,2015,43(16):65-72.WANG Xiaogang,ZHANG Jie.Enhanced Z-source three-level inverter based on switched-inductor[J].Power System Protection and Control,2015,43(16):65-72.
[4]杜强,高锋阳,乔垚,等.功率前馈的准Z源光伏并网逆变器Quasi-PR控制[J].高电压技术,2017,43(10):3322-3329.DU Qiang,GAO Fengyang,QIAO Yao,et al.Quasi-PR control strategy for quasi-Z source PV grid-connected inverter based on power feed-forward[J].High Voltage Engineering,2017,43(10):3322-3329.
[5]ZHANG R,LI Y,LIU Y.Constraints and control strategies of quasi-Z-source cascaded multilevel inverter[C]∥IECON 2017-43rd Annual Conference of the IEEE Industrial Electronics Society.Beijing,China:IEEE,2017.
[6]LI Y,GAO W,LI J,et al.Double line frequency ripple cancelling for single-phase quasi-Z-source inverter[C]∥2016 IEEE Energy Conversion Congress and Exposition(ECCE).Milwaukee,WI:IEEE,2016.
[7]GAJANAYAKE C J,VILATHGAMUWA D M,POH C L.Small-signal and signal-flow-graph modeling of switched Z-source impedance network[J].IEEE Power Electronics Letters,2005,3(3):111-116.
[8]GAJANAYAKE C J,VILATHGAMUWA D M,POH C L.Modeling and design of multi-loop closed loop controller for Z-source inverter for distributed generation[C]∥37th IEEE Power Electronics Specialists Conference.Jeju,Korea:IEEE,2006:1-7.
[9]李媛,彭方正.Z源/准Z源逆变器在光伏并网系统中的电容电压恒压控制策略[J].电工技术学报,2011,26(5):62-69.LI Yuan,PENG Fangzheng.Constant capacitor voltage control strategy for Z-source/quasi-Z-source inverter in grid-connected photovoltaic systems[J].Transactions of China Electro technical Society,2011,26(5):62-69.
[10]陈宗祥,蒋赢,潘俊民,等.基于滑模控制的Z源逆变器在单相光伏系统中的应用[J].中国电机工程学报,2008,28(21):33-39.CHEN Zongxiang,JIANG Ying,PAN Junmin,et al.A Z-source inverter for a single-phase PV system based on sliding-mode control[J].Proceedings of the CSEE,2008,28(21):33-39.
[11]郑建勇,刘孝辉.Z源光伏并网逆变器无差拍解耦控制[J].电网技术,2012,36(3):252-256.ZHENG Jianyong,LIU Xiaohui.Deadbeat decoupling control of Z-source grid-connected inverter[J].Power System Technology,2012,36(3):252-256.
[12]LIU Y,GE B,ABU-RUB H,et al.Model predictive direct power control for active power decoupled single phase quasi-Z-source inverter[J].IEEE Transactions on Industrial Informatics,2016,12(4):1550-1559.
[13]丁新平,钱照明,崔彬,等.基于模糊PID的Z源逆变器直流链升压电路控制[J].中国电机工程学报,2008,28(24):31-38.DING Xinping,QIAN Zhaoming,CUI Bin,et al.Fuzzy PID controller for DC-link boost voltage in Z-source inverter[J].Proceedings of the CSEE,2008,28(24):31-38.
[14]薛阳,李华郁,阚东跃,等.基于反馈线性化鲁棒控制μ方法的准开关升压型逆变器光伏并网策略[J].电力系统保护与控制,2017,45(1):47-52.XUE Yang,LI Huayu,KAN Dongyue,et al.Research on grid-connected control for the quasi-switched boost inverter of photovoltaic system based on feedback linearization andμ-synthesis method[J].Power System Protection and Control,2017,45(1):47-52.
[15]潘月斗,陈继义,徐杰,等.矩阵变换器输入电流的状态反馈线性化控制[J].高电压技术,2014,40(8):2497-2503.PAN Yuedou,CHEN Jiyi,XU Jie,et al.State feedback linearization control for current of input side in the matrix convertor[J].High Voltage Engineering,2014,40(8):2497-2503.
[16]GONG H,LI Y,WANG Y,et al.Input-output feedback linearization based control for quasi-Z-source inverter in photovoltaic application[C]∥2016 IEEE Energy Conversion Congress and Exposition.Milwaukee,WI,USA:IEEE,2016.
[17]FANG F,LI Y,ZHANG R,et al.An nonlinear control strategy for single phase quasi Z-source grid-connected inverter[C]∥IECON2017-43rd Annual Conference of the IEEE Industrial Electronics Society.Beijing,China:IEEE,2017.
[18]PAN D,RUAN X,BAO C,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.
[19]AYAD A,HASHEM M,HACKL C,et al.Proportional-resonant controller design for quasi-Z-source inverters with LC fil-ters[C]∥42nd Annual Conference of the IEEE Industrial Electronics Society.Florence,Italy:IEEE,2016.