为优化变压器选型与成本控制,首先,采用全生命周期成本(life cycle cost,LCC)理论和逼近理想解排序(technique for order preference by similarity to an ideal solution,TOPSIS)法,基于多项变电站工程变压器数据,探究变压器LCC构成及...为优化变压器选型与成本控制,首先,采用全生命周期成本(life cycle cost,LCC)理论和逼近理想解排序(technique for order preference by similarity to an ideal solution,TOPSIS)法,基于多项变电站工程变压器数据,探究变压器LCC构成及电压等级、接线方式、冷却方式等7项影响因素,对影响因素进行加权评估,并计算变压器LCC的各分项成本;其次,通过控制变量法量化电压等级等4项关键因素对变压器LCC的影响,探究关键因素对变压器成本机制的耦合效应,确定35 kV、220 kV及330 kV变压器LCC最低方案。结果显示,电压等级显著影响变压器LCC,接线方式与冷却方式对其的影响也较大;各分项成本在LCC中的占比保持相对稳定;单因素影响下,电压等级越高,变压器LCC越高,而是否为智能变压器对短期成本影响较小,长期来看智能变压器更具经济性。展开更多
为了实现永磁同步直线电机PMSLM(permanent magnet synchronous linear motor)高精度的多电气参数在线辨识,提出了一种基于双模型的递推最小二乘电气参数在线辨识算法。首先,根据电机的dq轴电压方程分别建立了辨识定子电阻、永磁体磁链...为了实现永磁同步直线电机PMSLM(permanent magnet synchronous linear motor)高精度的多电气参数在线辨识,提出了一种基于双模型的递推最小二乘电气参数在线辨识算法。首先,根据电机的dq轴电压方程分别建立了辨识定子电阻、永磁体磁链的模型1和辨识q轴电感、d轴电感的模型2,并将2个辨识模型循环结合。其次,基于上述双模型结构,采用递推最小二乘算法实现电气参数在线辨识,并针对PMSLM运行时存在大量动态过程的特性,提出一种具有饱和特性的分段变遗忘因子;然后,对功率开关非理想因素导致的误差电压进行补偿,进一步提高了辨识的精准度;最后,仿真和实验结果证明了该辨识算法的有效性,且具有收敛速度快、辨识结果精度高、多工况适用等优点。展开更多
This paper describes the fabrication and electrical characteristics of Ti/4H-SiC Schottky barrier diodes （SBDs）. The ideality factor n = 1.08 and effective Schottky barrier heightφ= 1.05eV of the SBDs were measured...This paper describes the fabrication and electrical characteristics of Ti/4H-SiC Schottky barrier diodes （SBDs）. The ideality factor n = 1.08 and effective Schottky barrier heightφ= 1.05eV of the SBDs were measured with the method of forward current density-voltage （J-V）. A low reverse leakage current below 5.96 ×10^-3A/cm^2 at a bias voltage of - 1. 1kV was obtained. By using B^＋ implantation,an amorphous layer as the edge termination was formed. We used the PECVD SiO2 as the field plate dielectric. The SBDs have an on-state current density of 430A/cm^2 at a forward voltage drop of about 4V. The specific on-resistance Ro, was found to be 6. 77mΩ2 · cm^2 .展开更多
文摘为优化变压器选型与成本控制,首先,采用全生命周期成本(life cycle cost,LCC)理论和逼近理想解排序(technique for order preference by similarity to an ideal solution,TOPSIS)法,基于多项变电站工程变压器数据,探究变压器LCC构成及电压等级、接线方式、冷却方式等7项影响因素,对影响因素进行加权评估,并计算变压器LCC的各分项成本;其次,通过控制变量法量化电压等级等4项关键因素对变压器LCC的影响,探究关键因素对变压器成本机制的耦合效应,确定35 kV、220 kV及330 kV变压器LCC最低方案。结果显示,电压等级显著影响变压器LCC,接线方式与冷却方式对其的影响也较大;各分项成本在LCC中的占比保持相对稳定;单因素影响下,电压等级越高,变压器LCC越高,而是否为智能变压器对短期成本影响较小,长期来看智能变压器更具经济性。
文摘为了实现永磁同步直线电机PMSLM(permanent magnet synchronous linear motor)高精度的多电气参数在线辨识,提出了一种基于双模型的递推最小二乘电气参数在线辨识算法。首先,根据电机的dq轴电压方程分别建立了辨识定子电阻、永磁体磁链的模型1和辨识q轴电感、d轴电感的模型2,并将2个辨识模型循环结合。其次,基于上述双模型结构,采用递推最小二乘算法实现电气参数在线辨识,并针对PMSLM运行时存在大量动态过程的特性,提出一种具有饱和特性的分段变遗忘因子;然后,对功率开关非理想因素导致的误差电压进行补偿,进一步提高了辨识的精准度;最后,仿真和实验结果证明了该辨识算法的有效性,且具有收敛速度快、辨识结果精度高、多工况适用等优点。
文摘This paper describes the fabrication and electrical characteristics of Ti/4H-SiC Schottky barrier diodes （SBDs）. The ideality factor n = 1.08 and effective Schottky barrier heightφ= 1.05eV of the SBDs were measured with the method of forward current density-voltage （J-V）. A low reverse leakage current below 5.96 ×10^-3A/cm^2 at a bias voltage of - 1. 1kV was obtained. By using B^＋ implantation,an amorphous layer as the edge termination was formed. We used the PECVD SiO2 as the field plate dielectric. The SBDs have an on-state current density of 430A/cm^2 at a forward voltage drop of about 4V. The specific on-resistance Ro, was found to be 6. 77mΩ2 · cm^2 .
