普及推广风电虚拟惯性控制技术,是保障含高比例风电电力系统频率稳定运行的重要需求,但当前缺乏精确估计风电场等效虚拟惯量的理论方法,不能定量评估风电场对电网的惯量贡献。鉴于此,针对风电场等效虚拟惯量的快速时变特征,提出应用受...普及推广风电虚拟惯性控制技术,是保障含高比例风电电力系统频率稳定运行的重要需求,但当前缺乏精确估计风电场等效虚拟惯量的理论方法,不能定量评估风电场对电网的惯量贡献。鉴于此,针对风电场等效虚拟惯量的快速时变特征,提出应用受控自回归辨识模型和基于时变遗忘因子的递推最小二乘辨识求解算法,估计出风电场等效虚拟惯量。所提辨识模型和算法具有快速跟踪能力和良好收敛性,能精确估计风电场快速时变的等效虚拟惯量。在辨识求解中,只需量测风电场公共耦合点(point of common coupling,PCC)的有功功率和频率扰动信息,数据易于获取、实用性强,可良好推广应用。最后通过算例系统验证了辨识模型与方法的有效性和精确性。展开更多
Two simple donor-acceptor multifunctional pure organic light-emitting molecules[(9H-carbazol-9-yl)(4-hydroxyphenyl)-methanone(CzMP)and(4-hydroxyphenyl)(10H-phenothiazin-10-yl)methanone(PTZMP)]with distinct aggregation...Two simple donor-acceptor multifunctional pure organic light-emitting molecules[(9H-carbazol-9-yl)(4-hydroxyphenyl)-methanone(CzMP)and(4-hydroxyphenyl)(10H-phenothiazin-10-yl)methanone(PTZMP)]with distinct aggregation-induced emission(AIE)properties were synthesized.Surprisingly,CzMP showed a long room temperature phosphorescence lifetime(>900 ms),and PTZMP exhibited triple emission of prompt fluorescence(PF),room temperature phosphorescence(RTP)and thermally activated delayed fluorescence(TADF).Furthermore,CzMP effectively responded to mechanical external forces and solvent fumigation,exhibiting dual-mode mechanochromic luminescence(MCL)including multiple fluorescence color shifts and phosphorescence switching.Time-dependent density functional theory(TDDFT)calculations were investigated to explain different luminescence properties of the two molecules,and the single crystal of CzMP was obtained and analyzed to demonstrate the unique molecular stacking pattern and strong intermolecular interactions in close association with phosphorescence emission.The multifunctional luminescent properties of the emitters explored in this work could be more effectively applied to a wide range of applications,such as information encryption and anti-counterfeiting.展开更多
Comprehensive unified power flow controller(UPFC)technology can calculate voltage control parameters of UPFC,but it increases the nonlinearity of Newton power flow calculation.When the comprehensive technology is comb...Comprehensive unified power flow controller(UPFC)technology can calculate voltage control parameters of UPFC,but it increases the nonlinearity of Newton power flow calculation.When the comprehensive technology is combined with the intelligent algorithm,the control parameters can only be optimized through the active and reactive power of UPFC on the branch,which makes the optimization convergence worse.Therefore,an optimal power flow calculation method for active distribution network based on improved comprehensive technology is proposed.First,based on the analysis of the influence of UPFC on branch power flow,an improved UPFC model is proposed.The accuracy of UPFC control parameters is enhanced by adjusting the voltage phase angle and regulation radius of series side transformer.Second,the optimal control model considering UPFC is established.Finally,the corresponding self-admittance and mutual admittance elements are extracted from the constructed UPFC model and introduced into the Jacobian matrix,so that while the comprehensive technology maintains the dimension of the Jacobian matrix,the intelligent algorithm can directly optimize the control parameters to reduce the search space.The IEEE33 bus system is used for example simulation,the results before and after the improvement are compared,and the Monte Carlo method is used to calculate the two algorithms 50 times respectively based on the installation number of UPFC,which verifies that the proposed optimization method has better convergence and operation speed.展开更多
文摘普及推广风电虚拟惯性控制技术,是保障含高比例风电电力系统频率稳定运行的重要需求,但当前缺乏精确估计风电场等效虚拟惯量的理论方法,不能定量评估风电场对电网的惯量贡献。鉴于此,针对风电场等效虚拟惯量的快速时变特征,提出应用受控自回归辨识模型和基于时变遗忘因子的递推最小二乘辨识求解算法,估计出风电场等效虚拟惯量。所提辨识模型和算法具有快速跟踪能力和良好收敛性,能精确估计风电场快速时变的等效虚拟惯量。在辨识求解中,只需量测风电场公共耦合点(point of common coupling,PCC)的有功功率和频率扰动信息,数据易于获取、实用性强,可良好推广应用。最后通过算例系统验证了辨识模型与方法的有效性和精确性。
文摘Two simple donor-acceptor multifunctional pure organic light-emitting molecules[(9H-carbazol-9-yl)(4-hydroxyphenyl)-methanone(CzMP)and(4-hydroxyphenyl)(10H-phenothiazin-10-yl)methanone(PTZMP)]with distinct aggregation-induced emission(AIE)properties were synthesized.Surprisingly,CzMP showed a long room temperature phosphorescence lifetime(>900 ms),and PTZMP exhibited triple emission of prompt fluorescence(PF),room temperature phosphorescence(RTP)and thermally activated delayed fluorescence(TADF).Furthermore,CzMP effectively responded to mechanical external forces and solvent fumigation,exhibiting dual-mode mechanochromic luminescence(MCL)including multiple fluorescence color shifts and phosphorescence switching.Time-dependent density functional theory(TDDFT)calculations were investigated to explain different luminescence properties of the two molecules,and the single crystal of CzMP was obtained and analyzed to demonstrate the unique molecular stacking pattern and strong intermolecular interactions in close association with phosphorescence emission.The multifunctional luminescent properties of the emitters explored in this work could be more effectively applied to a wide range of applications,such as information encryption and anti-counterfeiting.
基金the National Natural Science Foundation of China(51907104)。
文摘Comprehensive unified power flow controller(UPFC)technology can calculate voltage control parameters of UPFC,but it increases the nonlinearity of Newton power flow calculation.When the comprehensive technology is combined with the intelligent algorithm,the control parameters can only be optimized through the active and reactive power of UPFC on the branch,which makes the optimization convergence worse.Therefore,an optimal power flow calculation method for active distribution network based on improved comprehensive technology is proposed.First,based on the analysis of the influence of UPFC on branch power flow,an improved UPFC model is proposed.The accuracy of UPFC control parameters is enhanced by adjusting the voltage phase angle and regulation radius of series side transformer.Second,the optimal control model considering UPFC is established.Finally,the corresponding self-admittance and mutual admittance elements are extracted from the constructed UPFC model and introduced into the Jacobian matrix,so that while the comprehensive technology maintains the dimension of the Jacobian matrix,the intelligent algorithm can directly optimize the control parameters to reduce the search space.The IEEE33 bus system is used for example simulation,the results before and after the improvement are compared,and the Monte Carlo method is used to calculate the two algorithms 50 times respectively based on the installation number of UPFC,which verifies that the proposed optimization method has better convergence and operation speed.
