电网故障易造成并网风电场内风力发电机端电压骤变进而导致风力发电机跳闸,威胁风电场的安全运行。提出一种基于模型预测控制(Model Predictive Control,MPC)的风电场故障穿越有功无功优化控制策略。首先,基于下垂控制,根据并网点(Point...电网故障易造成并网风电场内风力发电机端电压骤变进而导致风力发电机跳闸,威胁风电场的安全运行。提出一种基于模型预测控制(Model Predictive Control,MPC)的风电场故障穿越有功无功优化控制策略。首先,基于下垂控制,根据并网点(Point of Common Coupling,PCC)电压得出故障下的风电场总有功无功参考值。其次,基于风电场的预测状态空间模型与功率-电压灵敏度计算公式,建立以最小化各风力发电机端电压波动为优化目标的基于MPC的优化问题数学模型,求解得到各风力发电机有功无功参考值。在深度故障下,协调控制静止无功发生器(Static Var Generator,SVG)补偿系统无功缺额以维持PCC电压稳定。仿真结果表明,所提控制策略能将PCC点电压与WT端电压快速有效地稳定在可行范围内,提升风电场的故障穿越能力。展开更多
We report the preparation of Cu_(2)Si_(x)Sn_(1−x)S_(3) thin films for thin film solar cell absorbers using the reactive magnetron co−sputtering technique.Energy dispersive spectrometer and x-ray diffraction analyses i...We report the preparation of Cu_(2)Si_(x)Sn_(1−x)S_(3) thin films for thin film solar cell absorbers using the reactive magnetron co−sputtering technique.Energy dispersive spectrometer and x-ray diffraction analyses indicate that Cu_(2)Si_(x)Sn_(1−x)S_(3) thin films can be synthesized successfully by partly substituting Si atoms for Sn atoms in the Cu_(2)SnS_(3) lattice,leading to a shrinkage of the lattice,and,accordingly,by 2θshifting to larger values.The blue shift of the Raman peak further confirms the formation of Cu_(2)Si_(x)Sn_(1−x)S_(3).Environmental scanning electron microscope analyses reveal a polycrystalline and homogeneous morphology with a grain size of about 200–300 nm.Optical measurements indicate an optical absorption coefficient of higher than 104 cm^(−1) and an optical bandgap of 1.17±0.01 eV.展开更多
文摘电网故障易造成并网风电场内风力发电机端电压骤变进而导致风力发电机跳闸,威胁风电场的安全运行。提出一种基于模型预测控制(Model Predictive Control,MPC)的风电场故障穿越有功无功优化控制策略。首先,基于下垂控制,根据并网点(Point of Common Coupling,PCC)电压得出故障下的风电场总有功无功参考值。其次,基于风电场的预测状态空间模型与功率-电压灵敏度计算公式,建立以最小化各风力发电机端电压波动为优化目标的基于MPC的优化问题数学模型,求解得到各风力发电机有功无功参考值。在深度故障下,协调控制静止无功发生器(Static Var Generator,SVG)补偿系统无功缺额以维持PCC电压稳定。仿真结果表明,所提控制策略能将PCC点电压与WT端电压快速有效地稳定在可行范围内,提升风电场的故障穿越能力。
基金Supported by the Natural Science Foundation of Hunan Province under Grant No.09JJ3110the Fundamental Research Funds for the Central Universities under Grant No.201021100029the Research Fund of Young Scholars for the Doctoral Program of Higher Education in China under Grant No.200805331121.
文摘We report the preparation of Cu_(2)Si_(x)Sn_(1−x)S_(3) thin films for thin film solar cell absorbers using the reactive magnetron co−sputtering technique.Energy dispersive spectrometer and x-ray diffraction analyses indicate that Cu_(2)Si_(x)Sn_(1−x)S_(3) thin films can be synthesized successfully by partly substituting Si atoms for Sn atoms in the Cu_(2)SnS_(3) lattice,leading to a shrinkage of the lattice,and,accordingly,by 2θshifting to larger values.The blue shift of the Raman peak further confirms the formation of Cu_(2)Si_(x)Sn_(1−x)S_(3).Environmental scanning electron microscope analyses reveal a polycrystalline and homogeneous morphology with a grain size of about 200–300 nm.Optical measurements indicate an optical absorption coefficient of higher than 104 cm^(−1) and an optical bandgap of 1.17±0.01 eV.
