The research of hub vibratory loads is a very complicated problem of blade aeroelastic response. Based on the airflow environment of blade, the method of hub vibratory loads prediction will be produced when the helico...The research of hub vibratory loads is a very complicated problem of blade aeroelastic response. Based on the airflow environment of blade, the method of hub vibratory loads prediction will be produced when the helicopter flights forward with high speed. It involves the Leishman-Beddoes unsteady model and dynamic stall model, the dynamic inflow theory, the Piters-He generalized dynamic wake theory, elastic flap movement of blade and so on. The State-Space method is used to solve the equation, which is fit for numerical calculation. Comparing calculational results of several models, it is revealed that the distributions of rotor wake and blade dynamic response have great influence upon the hub vibratory loads prediction.展开更多
构建区域综合能源系统(Regional Integrated Energy System,RIES)是应对高比例可再生能源联网的有效途径。但RIES调度方案的有效性易受到源荷不确定性与不同能源转换设备的变工况特性的影响。所以文中提出一种随机优化运行方法。首先,...构建区域综合能源系统(Regional Integrated Energy System,RIES)是应对高比例可再生能源联网的有效途径。但RIES调度方案的有效性易受到源荷不确定性与不同能源转换设备的变工况特性的影响。所以文中提出一种随机优化运行方法。首先,创建动态能源集线器(Dynamic Energy Hub,DEH)模型,建立各设备模型及目标函数,提出考虑设备变工况特性的RIES优化调度方法;其次,通过K-means聚类的方法表征源荷不确定性,并获得典型系统运行场景;最后,结合DEH模型,确定最优调度方案及各能源转换设备的容量配置结果。优化结果表明,所提方法可以对区域综合能源系统多类能源进行合理调度,提升系统运行经济性和可再生能源消纳能力,减少碳排放。展开更多
为解决交流配电系统存在设备负载率低、冗余度大、故障后恢复供电时间长等问题,提出了一种基于柔性直流的不间断电力交换器(uninterrupted power hub,UPH),并利用电压源换流器将多个配电变电站互联,以实现变电站间负载率均衡、负荷转供...为解决交流配电系统存在设备负载率低、冗余度大、故障后恢复供电时间长等问题,提出了一种基于柔性直流的不间断电力交换器(uninterrupted power hub,UPH),并利用电压源换流器将多个配电变电站互联,以实现变电站间负载率均衡、负荷转供等功能。论文分析了UPH的主要运行方式和控制策略,并通过数字仿真分析了UPH的控制性能。研究结果表明,通过设置固定与变电站连接及灵活在各个变电站切换这2种换流器,并合理配置其容量,UPH可比传统互联方案节省较大的换流器总体容量,是柔性直流技术提升配电网设备利用率和可靠性的一种新方案。论文研究可为柔性直流技术在配电系统中的应用提供参考。展开更多
Based on FEM theory,a method of dynamic analysis for hingeless rotors considering anisotropic composite materials is established.A parametric modeling method of composite blade with typical profile and high simulation...Based on FEM theory,a method of dynamic analysis for hingeless rotors considering anisotropic composite materials is established.A parametric modeling method of composite blade with typical profile and high simulation degree for design is proposed.Through the finite element method,the profile characteristics of rotor blade can be obtained efficiently and accurately,and the synchronization of parametric design and finite element analysis of structural characteristics can be realized.Then a 23-degrees of freedom non-linear beam element is used to simulate the extended one-dimensional beam,thereby a nonlinear differential equation describing the elastic motion of the rotor is established.To obtain the crosssectional target characteristics of the blades,an inverse design method is proposed for cross-section components based on combinatorial optimization algorithm.The calculation and validation work show that the proposed model can effectively analyze the aeroelastic characteristics of general composite rotors.Further,the influence of cross-sectional parameters on the aeroelastic stability and hub loads of hingeless rotor is analyzed and some remarkable conclusions are obtained.展开更多
文摘The research of hub vibratory loads is a very complicated problem of blade aeroelastic response. Based on the airflow environment of blade, the method of hub vibratory loads prediction will be produced when the helicopter flights forward with high speed. It involves the Leishman-Beddoes unsteady model and dynamic stall model, the dynamic inflow theory, the Piters-He generalized dynamic wake theory, elastic flap movement of blade and so on. The State-Space method is used to solve the equation, which is fit for numerical calculation. Comparing calculational results of several models, it is revealed that the distributions of rotor wake and blade dynamic response have great influence upon the hub vibratory loads prediction.
文摘构建区域综合能源系统(Regional Integrated Energy System,RIES)是应对高比例可再生能源联网的有效途径。但RIES调度方案的有效性易受到源荷不确定性与不同能源转换设备的变工况特性的影响。所以文中提出一种随机优化运行方法。首先,创建动态能源集线器(Dynamic Energy Hub,DEH)模型,建立各设备模型及目标函数,提出考虑设备变工况特性的RIES优化调度方法;其次,通过K-means聚类的方法表征源荷不确定性,并获得典型系统运行场景;最后,结合DEH模型,确定最优调度方案及各能源转换设备的容量配置结果。优化结果表明,所提方法可以对区域综合能源系统多类能源进行合理调度,提升系统运行经济性和可再生能源消纳能力,减少碳排放。
文摘为解决交流配电系统存在设备负载率低、冗余度大、故障后恢复供电时间长等问题,提出了一种基于柔性直流的不间断电力交换器(uninterrupted power hub,UPH),并利用电压源换流器将多个配电变电站互联,以实现变电站间负载率均衡、负荷转供等功能。论文分析了UPH的主要运行方式和控制策略,并通过数字仿真分析了UPH的控制性能。研究结果表明,通过设置固定与变电站连接及灵活在各个变电站切换这2种换流器,并合理配置其容量,UPH可比传统互联方案节省较大的换流器总体容量,是柔性直流技术提升配电网设备利用率和可靠性的一种新方案。论文研究可为柔性直流技术在配电系统中的应用提供参考。
文摘Based on FEM theory,a method of dynamic analysis for hingeless rotors considering anisotropic composite materials is established.A parametric modeling method of composite blade with typical profile and high simulation degree for design is proposed.Through the finite element method,the profile characteristics of rotor blade can be obtained efficiently and accurately,and the synchronization of parametric design and finite element analysis of structural characteristics can be realized.Then a 23-degrees of freedom non-linear beam element is used to simulate the extended one-dimensional beam,thereby a nonlinear differential equation describing the elastic motion of the rotor is established.To obtain the crosssectional target characteristics of the blades,an inverse design method is proposed for cross-section components based on combinatorial optimization algorithm.The calculation and validation work show that the proposed model can effectively analyze the aeroelastic characteristics of general composite rotors.Further,the influence of cross-sectional parameters on the aeroelastic stability and hub loads of hingeless rotor is analyzed and some remarkable conclusions are obtained.
