弱电网下LCL型逆变器自适应控制策略
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摘要
LCL滤波器能强有力地衰减开关切换引起的谐波,被广泛应用于并网逆变系统中。然而,LCL滤波器存在谐振抑制问题,电容电流反馈等有源阻尼不失为行之有效的方法。但引入电网阻抗的弱电网工况会严重影响LCL型并网逆变器的控制性能。文中提出一种基于并网电流有源阻尼的LCL型并网逆变器自适应控制方法,采用即时触发型阻抗测量方法在线检测电网阻抗,实时修正电流控制器与有源阻尼控制器的控制参数,实现逆变器在弱电网下的自适应控制,使得系统在电网阻抗大范围变化下稳定运行。方案无需增加额外的传感器,降低了设备成本。论文最后通过实验验证了并网逆变器自适应控制策略的有效性。
LCL filter has been widely used in the grid-connected inverter due to the higher attenuation of the switching frequency harmonics. However,the resonance of the LCL filter is a severe problem to be solved,the capacitor-current-feedback active damping is considered as the effective method. But the control performance of grid-connected inverter will be affected by the weak power grid with impedance. In this paper,an adaptive control scheme of LCL filter-based grid-connected inverter based on grid-current-feedback active damping was proposed. The grid impedance on line by using immediately triggered impedance measurement method is detected, the constantly control parameters of the current controller and the active damping controller are updated, and the adaptive control strategy of the grid-connected inverter under weak power grid is formed. So the system can be stably operated under the wide variation of the grid impedance. In addition,it does not need to add any extra sensor in this scheme,the device cost will be reduced. Finally,a prototype was built and the effectiveness of the proposed adaptive control strategy of the grid-connected inverter was validated by experimental results.
LCL filter has been widely used in the grid-connected inverter due to the higher attenuation of the switching frequency harmonics. However,the resonance of the LCL filter is a severe problem to be solved,the capacitor-current-feedback active damping is considered as the effective method. But the control performance of grid-connected inverter will be affected by the weak power grid with impedance. In this paper,an adaptive control scheme of LCL filter-based grid-connected inverter based on grid-current-feedback active damping was proposed. The grid impedance on line by using immediately triggered impedance measurement method is detected, the constantly control parameters of the current controller and the active damping controller are updated, and the adaptive control strategy of the grid-connected inverter under weak power grid is formed. So the system can be stably operated under the wide variation of the grid impedance. In addition,it does not need to add any extra sensor in this scheme,the device cost will be reduced. Finally,a prototype was built and the effectiveness of the proposed adaptive control strategy of the grid-connected inverter was validated by experimental results.
引文
[1]唐振东,杨洪耕,袁林.弱电网下多逆变器并网控制通道间的交互影响分析[J].电网技术,2016,40(11):3524-3531.Tang Z D,Yang H G,Yuan L.Interaction analysis between multiple inverters and grid control channels under weak current network[J].Power Grid Technology,2016,40(11):3524-3531.
[2]Piwko R,Miller N.Integrating large wind farms into weak power grids with long transmission lines[C].Conference Proceedings of Ces/ieee,International Power Electronics and Motion Control Conference,2006:1-7.
[3]郑昕昕,肖岚,王长宝,等.三相变流器LCL滤波器参数优化新方法[J].中国电机工程学报,2013,33(12):55-63.Zheng X X,Xiao L,Wang C B,et al.New method of parameter optimization for LCL filter of three-phase converter[J].Proceedings of the Chinese Academy of Electrical Engineering,2013,33(12):55-63.
[4]Hanif M,Khadkikar V,Xiao W,et al.Two degrees of freedom active damping technique for,$LCL$filter-based grid connected PV systems[J].IEEE Transactions on Industrial Electronics,2014,61(6):2795-2803.
[5]Wang X,Blaabjerg F,Loh P C.Grid-current-feedback active damping for LCL resonance in grid-connected voltage-source converters[J].IEEE Transactions on Power Electronics,2015,31(1):213-223.
[6]Malinowski M,Bernet S.A simple voltage sensorless active damping scheme for three-phase PWM converters with an$LCL$Filter[J].IEEE Transactions on Industrial Electronics,2008,55(4):1876-1880.
[7]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 D H,Ruan X B,Wang X H,et al.Control parameter design of enhanced LCL type grid connected inverter to power network impedance robustness[J].Journal of China Electrical Engineering,2015,35(10):2558-2566.
[8]张奔奔,胥芳,吴乐彬,等.LCL型并网逆变器自适应谐振抑制[J].浙江大学学报(工学版),2016,50(1):180-185.Zhang B B,Xu F,Wu L B,et al.Adaptive resonance suppression of LCL type grid connected inverter[J].Journal of Zhejiang University(Engineering Edition),2016,50(1):180-185.
[9]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.
[10]陈新,王赟程,华淼杰,等.采用混合阻尼自适应调整的并网逆变器控制方法[J].中国电机工程学报,2016,39(3):765-774.Chen X,Wang Y C,Hua M J,et al.Control method of grid connected inverter with adaptive damping adjustment[J].Proceedings of the Chinese Institute of Electrical Engineering,2016,39(3):765-774.
[11]Berriri H,Naouar M W,Slama-Belkhodja I.Easy and fast sensor fault detection and isolation algorithm for electrical drives[J].IEEE Transactions on Power Electronics,2012,27(2):490-499.
[12]高国燊,余文烋,等.自动控制原理[M].广州:华南理工出版社,2009.Gao G S,Yu W J,et al.Principles of automatic control[M].Guangzhou:Huanan Science and Technology Press,2009
[13]陈兵,卢圣文.空间矢量PWM数字化实现方法研究[J].湘潭大学自然科学学报,2009,31(3):154-159.Chen B,Lu S W.Digital realization method of space vector PWM[J].Journal of Natural Science,Xiangtan University,2009,31(3):154-159.
[14]张崇巍,,张兴.PWM整流器及其控制[M].北京:机械工业出版社,2003.Zhang C W,Zhang X.PWM Rectifier and its Control[M].Beijing:Machinery Industry Press,2003.
[15]邱雪娜,徐青鹤,张雪君.100 k W光伏并网逆变器系统设计[J].控制工程,2013,20(1):76-79.Qiu X N,Xu Q H,Zhang X J.100 k W photovoltaic grid connected inverter system design[J].Control Engineering of China,2013,20(1):76-79.
[2]Piwko R,Miller N.Integrating large wind farms into weak power grids with long transmission lines[C].Conference Proceedings of Ces/ieee,International Power Electronics and Motion Control Conference,2006:1-7.
[3]郑昕昕,肖岚,王长宝,等.三相变流器LCL滤波器参数优化新方法[J].中国电机工程学报,2013,33(12):55-63.Zheng X X,Xiao L,Wang C B,et al.New method of parameter optimization for LCL filter of three-phase converter[J].Proceedings of the Chinese Academy of Electrical Engineering,2013,33(12):55-63.
[4]Hanif M,Khadkikar V,Xiao W,et al.Two degrees of freedom active damping technique for,$LCL$filter-based grid connected PV systems[J].IEEE Transactions on Industrial Electronics,2014,61(6):2795-2803.
[5]Wang X,Blaabjerg F,Loh P C.Grid-current-feedback active damping for LCL resonance in grid-connected voltage-source converters[J].IEEE Transactions on Power Electronics,2015,31(1):213-223.
[6]Malinowski M,Bernet S.A simple voltage sensorless active damping scheme for three-phase PWM converters with an$LCL$Filter[J].IEEE Transactions on Industrial Electronics,2008,55(4):1876-1880.
[7]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 D H,Ruan X B,Wang X H,et al.Control parameter design of enhanced LCL type grid connected inverter to power network impedance robustness[J].Journal of China Electrical Engineering,2015,35(10):2558-2566.
[8]张奔奔,胥芳,吴乐彬,等.LCL型并网逆变器自适应谐振抑制[J].浙江大学学报(工学版),2016,50(1):180-185.Zhang B B,Xu F,Wu L B,et al.Adaptive resonance suppression of LCL type grid connected inverter[J].Journal of Zhejiang University(Engineering Edition),2016,50(1):180-185.
[9]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.
[10]陈新,王赟程,华淼杰,等.采用混合阻尼自适应调整的并网逆变器控制方法[J].中国电机工程学报,2016,39(3):765-774.Chen X,Wang Y C,Hua M J,et al.Control method of grid connected inverter with adaptive damping adjustment[J].Proceedings of the Chinese Institute of Electrical Engineering,2016,39(3):765-774.
[11]Berriri H,Naouar M W,Slama-Belkhodja I.Easy and fast sensor fault detection and isolation algorithm for electrical drives[J].IEEE Transactions on Power Electronics,2012,27(2):490-499.
[12]高国燊,余文烋,等.自动控制原理[M].广州:华南理工出版社,2009.Gao G S,Yu W J,et al.Principles of automatic control[M].Guangzhou:Huanan Science and Technology Press,2009
[13]陈兵,卢圣文.空间矢量PWM数字化实现方法研究[J].湘潭大学自然科学学报,2009,31(3):154-159.Chen B,Lu S W.Digital realization method of space vector PWM[J].Journal of Natural Science,Xiangtan University,2009,31(3):154-159.
[14]张崇巍,,张兴.PWM整流器及其控制[M].北京:机械工业出版社,2003.Zhang C W,Zhang X.PWM Rectifier and its Control[M].Beijing:Machinery Industry Press,2003.
[15]邱雪娜,徐青鹤,张雪君.100 k W光伏并网逆变器系统设计[J].控制工程,2013,20(1):76-79.Qiu X N,Xu Q H,Zhang X J.100 k W photovoltaic grid connected inverter system design[J].Control Engineering of China,2013,20(1):76-79.