弱电网下并网变流器的带阻前馈控制策略研究
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摘要
电网电压前馈被广泛用来改善变流器的启动性能,然而,采用传统电网电压前馈时,随着感性电网阻抗的增大,系统的稳定性会迅速降低,甚至失稳。首先建立了含有感性电网阻抗和电网电压前馈时系统的数学模型,并基于阻抗分析法对变流器对弱电网的适应能力进行了分析。为了提高变流器对弱电网的适应能力,提出了基于带阻滤波的电网电压前馈策略。最后,搭建了系统仿真模型,仿真结果验证了理论分析的正确性和所提控制策略的有效性。
Grid-voltage feedforward is widely used to improve the startup performance of the converter.However,the system stability is reduced quickly as the inductive grid impedance increased when the traditional grid-voltage feedforward is adopted and even the system may be unstable.First,the mathematical model of the system considering the inductive grid impedance and grid-voltage feedforward was established.In addition,the adaptive ability of the converter to the weak grid was analyzed based on the impedance criterion.In order to improve the adaptive ability of the converter to the weak grid,grid-voltage feedforward control method based on the band-stop filter was proposed.Finally,the simulation model of the system was built.The simulation results confirm the validity of the analysis and the effectiveness of the proposed strategy.
Grid-voltage feedforward is widely used to improve the startup performance of the converter.However,the system stability is reduced quickly as the inductive grid impedance increased when the traditional grid-voltage feedforward is adopted and even the system may be unstable.First,the mathematical model of the system considering the inductive grid impedance and grid-voltage feedforward was established.In addition,the adaptive ability of the converter to the weak grid was analyzed based on the impedance criterion.In order to improve the adaptive ability of the converter to the weak grid,grid-voltage feedforward control method based on the band-stop filter was proposed.Finally,the simulation model of the system was built.The simulation results confirm the validity of the analysis and the effectiveness of the proposed strategy.
引文
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[2]国家电网公司. Q/GDW 617—2011光伏电站接入电网技术规定[S].北京:中国电力出版社,2011.
[3] Bakhshizadeh M K,Wang X,Blaabjerg F,et al. Couplings in Phase Domain Impedance Modeling of Grid-connected Converters[J]. IEEE Transactions on Power Electronics,2016,31(10):6792-6796.
[4] Alemi P,Jeong S Y,Lee D C. Control Active Damping of LLCL Filters Using PR Control for Grid-connected Three-level T-type Converters[J]. Journal of Power Electronics,2015,15(3):786-795.
[5] Xu J,Xie S,Tang T. Evaluations of Current Control in Weak Grid Case for Grid-connected LCL-filtered Inverter[J]. IET Power Electronics,2013,6(2):98-106.
[6] Xu J,Qian Q,Xie S,et al. Grid-voltage Feedforward Based Control for Grid-connected LCL-filtered Inverter with High Robustness and Low Grid Current Distortion in Weak Grid[C]//2016 IEEE Applied Power Electronic Conference and Exposition(APEC),2016:1919-1925.
[7]许津铭,谢少军,唐婷.弱电网下LCL滤波并网逆变器自适应电流控制[J].中国电机工程学报,2014,34(24):4031-4039.
[8] Freijedo F,Vidal A,Yepes A G,et al. Tuning of Synchronousframe PI Current Controllers in Grid-connected Converters Operating at a Low Sampling Rate by MIMO Root Locus[J].IEEE Transactions on Industrial Electronics,2015,62(8):5006-5016.
[9]郑晨,周林,解宝,等.基于相位裕度补偿的大型光伏电站谐波谐振抑制策略[J].电工技术学报,2016,31(19):85-96.
[2]国家电网公司. Q/GDW 617—2011光伏电站接入电网技术规定[S].北京:中国电力出版社,2011.
[3] Bakhshizadeh M K,Wang X,Blaabjerg F,et al. Couplings in Phase Domain Impedance Modeling of Grid-connected Converters[J]. IEEE Transactions on Power Electronics,2016,31(10):6792-6796.
[4] Alemi P,Jeong S Y,Lee D C. Control Active Damping of LLCL Filters Using PR Control for Grid-connected Three-level T-type Converters[J]. Journal of Power Electronics,2015,15(3):786-795.
[5] Xu J,Xie S,Tang T. Evaluations of Current Control in Weak Grid Case for Grid-connected LCL-filtered Inverter[J]. IET Power Electronics,2013,6(2):98-106.
[6] Xu J,Qian Q,Xie S,et al. Grid-voltage Feedforward Based Control for Grid-connected LCL-filtered Inverter with High Robustness and Low Grid Current Distortion in Weak Grid[C]//2016 IEEE Applied Power Electronic Conference and Exposition(APEC),2016:1919-1925.
[7]许津铭,谢少军,唐婷.弱电网下LCL滤波并网逆变器自适应电流控制[J].中国电机工程学报,2014,34(24):4031-4039.
[8] Freijedo F,Vidal A,Yepes A G,et al. Tuning of Synchronousframe PI Current Controllers in Grid-connected Converters Operating at a Low Sampling Rate by MIMO Root Locus[J].IEEE Transactions on Industrial Electronics,2015,62(8):5006-5016.
[9]郑晨,周林,解宝,等.基于相位裕度补偿的大型光伏电站谐波谐振抑制策略[J].电工技术学报,2016,31(19):85-96.