电子电力变压器并联运行的自适应下垂控制策略
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摘要
电子电力变压器(EPT)采用并联运行方式,可以提高电网供电的可靠性。在并联过程中下垂控制策略应用最为广泛。传统的下垂控制在线路阻抗不相等时会导致负荷分配不均并产生环流。为解决这一问题,提出了一种自适应下垂控制策略,将并联运行的EPT输出级功率的一次函数变成P、Q的二次函数,根据各自的额定容量求出对应的功率比例,调节实际输出功率,使EPT按额定容量成正比分配负荷,减小了线路阻抗不均造成的影响。在Matlab/Simulink中搭建仿真模型,并联系统动态性能良好,仿真结果验证了所提出控制策略的有效性和可行性。
The parallel operation of electronic power transformers(EPTs)can improve the reliability of power supplyfrom power grid,in which the droop control strategy is most widely used. When the line impedance is unequal,the tra-ditional droop control strategies will cause uneven load distribution and circulation. To solve this problem,an adaptivedroop control strategy is proposed,under which the linear function of each output power from the EPT in the parallel op-eration process is transformed into a quadratic function with respect to P and Q;the corresponding power ratio is calcu-lated according to the rated capacity of each EPT,respectively;the actual output power of EPTs is adjusted to shareload in proportion to the rated capacity,thus reducing the impact of uneven line impedance. A simulation model is builtbased on Matlab/Simulink. The parallel system has a satisfying dynamic performance,and simulation results verify theeffectiveness and feasibility of the proposed control strategy.
The parallel operation of electronic power transformers(EPTs)can improve the reliability of power supplyfrom power grid,in which the droop control strategy is most widely used. When the line impedance is unequal,the tra-ditional droop control strategies will cause uneven load distribution and circulation. To solve this problem,an adaptivedroop control strategy is proposed,under which the linear function of each output power from the EPT in the parallel op-eration process is transformed into a quadratic function with respect to P and Q;the corresponding power ratio is calcu-lated according to the rated capacity of each EPT,respectively;the actual output power of EPTs is adjusted to shareload in proportion to the rated capacity,thus reducing the impact of uneven line impedance. A simulation model is builtbased on Matlab/Simulink. The parallel system has a satisfying dynamic performance,and simulation results verify theeffectiveness and feasibility of the proposed control strategy.
引文
[1]毛承雄,王丹,范澍,等.电子电力变压器[M].北京:中国电力出版社,2010.
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[4]王丹,毛承雄,陆继明(Wang Dan,Mao Chengxiong,Lu Jiming).电子电力变压器的并联运行(Parallel operation of electronic power transformer)[J].电力系统自动化(Automation of Electric Power Systems),2005,29(16):66-71.
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[8]鲍薇,胡学浩,李光辉,等(Bao Wei,Hu Xuehao,Li Guanghui,et al).独立型微电网中基于虚拟阻抗的改进下垂控制(An improved droop control strategy based on virtual impedance in islanded micro-grid)[J].电力系统保护与控制(Power System Protection and Control),2013,41(16):7-13.
[9]阳敏,罗安,肖华根,等(Yang Min,Luo An,Xiao Huagen,et al).多逆变器并联系统环流分析及抑制方法(Circulating current analysis and suppression method for multi-inverter parallel system)[J].电力系统及其自动化学报(Proceedings of the CSU-EPSA),2017,29(10):6-11.
[10]He Jinwei,Li Yunwei.An enhanced microgrid load demand sharing strategy[J].IEEE Trans on Power Electronics,2012,27(9):3984-3995.
[11]王成山,肖朝霞,王守相(Wang Chengshan,Xiao Zhaoxia,Wang Shouxiang).微网中分布式电源逆变器的多环反馈控制策略(Multiple feedback loop control scheme for inverters of the micro source in microgrids)[J].电工技术学报(Transactions of China Electrotechnical Society),2009,24(2):100-107.
[12]Matas J,Castilla M,Vicuna L G,et al.Virtual impedance loop for droop-controlled single-phase parallel inverters using a second-order general-integrator scheme[J].IEEETrans on Power Electronics,2010,25(12):2993-3002.
[13]Mahmood H,Michaelson D,Jin Jiang.Accurate reactive power sharing in an islanded microgrid using adaptive virtual impedances[J].IEEE Trans on Industrial Electronics,2015,30(3):1605-1617.
[14]姚俊,杜红彪,周特,等(Yao Jun,Du Hongbiao,Zhou Te,et al).微网逆变器并联运行的改进下垂控制策略(Improved droop control strategy for inverters parallel operation in micro-grid)[J].电网技术(Power System Technology),2015,39(4):932-938.
[15]郭倩,林燎源,武宏彦,等(Guo Qian,Lin Liaoyuan,Wu Hongyan,et al).一种改进的分布式电源无功功率精确分配下垂控制策略(An improved droop control strategy for accurate reactive power sharing among distributed generators)[J].电力系统自动化(Automation of Electric Power Systems),2015,39(15):30-34,74.
[16]陈昕,张昌华,黄琦,等(Chen Xin,Zhang Changhua,Huang Qi,et al).引入功率微分项下垂控制的逆变器并联系统小信号稳定性分析(Small-signal stability analysis of parallel inverter system with power differential term droop control)[J].电网技术(Power System Technology),2016,40(11):3467-3475.
[17]Wang Yi,Jiang Hanhong,Zhou Liang,et al.An improved adaptive droop control strategy for power sharing in microgrid[C]//8th International Conference on Intelligent Human-Machine Systems and Cybernetics.Hangzhou,China,2016:50-53.
[18]孙孝峰,杨雅麟,赵巍,等(Sun Xiaofeng,Yang Yalin,Zhao Wei,et al).微电网逆变器自适应下垂控制策略(An adaptive droop control method for inverters in microgrid)[J].电网技术(Power System Technology),2014,38(9):2386-2391.
[2]Wang Dan,Tian Jie,Mao Chengxiong,et al.A 10-kV/400-V 500-kVA electronic power transformer[J].IEEE Trans on Industrial Electronics,2016,63(11):6653-6663.
[3]Liu Haibo,Mao Chengxiong,Lu Jiming,et al.Parallel operation of electronic power transformer based on distributed logic control[C]//42nd International Universities Power Engineering Conference.Brighton,UK,2007:93-101.
[4]王丹,毛承雄,陆继明(Wang Dan,Mao Chengxiong,Lu Jiming).电子电力变压器的并联运行(Parallel operation of electronic power transformer)[J].电力系统自动化(Automation of Electric Power Systems),2005,29(16):66-71.
[5]刘海波,毛承雄,陆继明,等(Liu Haibo,Mao Chengxiong,Lu Jiming,et al).基于无互联线控制的电子电力变压器并联技术(Parallel operation of electronic power transformers without control interconnections)[J].电力系统自动化(Automation of Electric Power Systems),2007,31(15):55-60.
[6]De Brabandere K,Bolsens B,Van den Keybus J,et al.Avoltage and frequency droop control method for parallel inverters[J].IEEE Trans on Industrial Electronics,2007,22(4):1107-1115.
[7]郑永伟,陈民铀,李闯,等(Zheng Yongwei,Chen Minyou,Li Chuang,et al).自适应调节下垂系数的微电网控制策略(A microgrid control strategy based on adaptive drooping coefficient adjustment)[J].电力系统自动化(Automation of Electric Power Systems),2013,37(7):6-11.
[8]鲍薇,胡学浩,李光辉,等(Bao Wei,Hu Xuehao,Li Guanghui,et al).独立型微电网中基于虚拟阻抗的改进下垂控制(An improved droop control strategy based on virtual impedance in islanded micro-grid)[J].电力系统保护与控制(Power System Protection and Control),2013,41(16):7-13.
[9]阳敏,罗安,肖华根,等(Yang Min,Luo An,Xiao Huagen,et al).多逆变器并联系统环流分析及抑制方法(Circulating current analysis and suppression method for multi-inverter parallel system)[J].电力系统及其自动化学报(Proceedings of the CSU-EPSA),2017,29(10):6-11.
[10]He Jinwei,Li Yunwei.An enhanced microgrid load demand sharing strategy[J].IEEE Trans on Power Electronics,2012,27(9):3984-3995.
[11]王成山,肖朝霞,王守相(Wang Chengshan,Xiao Zhaoxia,Wang Shouxiang).微网中分布式电源逆变器的多环反馈控制策略(Multiple feedback loop control scheme for inverters of the micro source in microgrids)[J].电工技术学报(Transactions of China Electrotechnical Society),2009,24(2):100-107.
[12]Matas J,Castilla M,Vicuna L G,et al.Virtual impedance loop for droop-controlled single-phase parallel inverters using a second-order general-integrator scheme[J].IEEETrans on Power Electronics,2010,25(12):2993-3002.
[13]Mahmood H,Michaelson D,Jin Jiang.Accurate reactive power sharing in an islanded microgrid using adaptive virtual impedances[J].IEEE Trans on Industrial Electronics,2015,30(3):1605-1617.
[14]姚俊,杜红彪,周特,等(Yao Jun,Du Hongbiao,Zhou Te,et al).微网逆变器并联运行的改进下垂控制策略(Improved droop control strategy for inverters parallel operation in micro-grid)[J].电网技术(Power System Technology),2015,39(4):932-938.
[15]郭倩,林燎源,武宏彦,等(Guo Qian,Lin Liaoyuan,Wu Hongyan,et al).一种改进的分布式电源无功功率精确分配下垂控制策略(An improved droop control strategy for accurate reactive power sharing among distributed generators)[J].电力系统自动化(Automation of Electric Power Systems),2015,39(15):30-34,74.
[16]陈昕,张昌华,黄琦,等(Chen Xin,Zhang Changhua,Huang Qi,et al).引入功率微分项下垂控制的逆变器并联系统小信号稳定性分析(Small-signal stability analysis of parallel inverter system with power differential term droop control)[J].电网技术(Power System Technology),2016,40(11):3467-3475.
[17]Wang Yi,Jiang Hanhong,Zhou Liang,et al.An improved adaptive droop control strategy for power sharing in microgrid[C]//8th International Conference on Intelligent Human-Machine Systems and Cybernetics.Hangzhou,China,2016:50-53.
[18]孙孝峰,杨雅麟,赵巍,等(Sun Xiaofeng,Yang Yalin,Zhao Wei,et al).微电网逆变器自适应下垂控制策略(An adaptive droop control method for inverters in microgrid)[J].电网技术(Power System Technology),2014,38(9):2386-2391.