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关键词： SiC   MOSFET   短路耐受时间   短路保护   开尔文源极   驱动电路  

摘要： 为了提高SiC MOSFET的短路可靠性，在不同的母线电压、驱动电压、驱动电阻、主回路寄生电感以及栅极阈值电压参数下，对SiC MOSFET短路电流特性曲线进行测量，定量分析各个参数对短路电流的影响，为如何提高SiC MOSEFT的短路耐受时间提供解决思路。同时由于SiC MOSFET的短路耐受时间，决定着对其进行短路保护动作的最大时间，所以这些不同参数的设置直接影响着SiC MOSFET短路保护电路的设计。在传统SiC MOSFET短路保护策略中，利用开尔文源极与功率源极之间寄生电感产生的感应电压，配合RC滤波器进行短路保护，存在SiC MOSFET在硬开关短路和负载短路中，触发短路保护动作阈值不一致的问题，即导致短路保护失败。针对此问题，提出基于di/dt-PMOS的短路保护策略，保证了阈值的一致性。通过公式推导以及实验，结果表明基于di/dt-PMOS的SiC MOSFET短路保护策略的有效性。

关键词： Radiation effects   Electrons   MOSFET   Logic gates   Annealing   Silicon carbide   Tunneling   Charge carrier lifetime   Couplings   Threshold voltage   4H-silicon carbide (SiC)   coupling effects   electron irradiation   short circuit (SC) characteristics  

摘要： In this article, the electron irradiation coupling short circuit (SC) characteristics of 4H-silicon carbide (SiC) MOSFET are studied. The SC influence mechanism of electron irradiation coupling is proposed, and the influence of minority carrier lifetime on the SC characteristics of the device after irradiation is further studied. The 4H-SiC MOSFET and 4H-SiC wafer are irradiated by 2-MeV electrons. The changes in static parameters of 4H-SiC MOSFET are analyzed, and the SC characteristics of 4H-SiC MOSFET under electron irradiation coupling are studied by the limit SC (LSC) test method. The results show that after irradiation, the SC peak current of 4H-SiC MOSFET increases by 9.6%, the critical SC failure time (t(crit)) decreases by 10.85%, and the critical SC failure energy (E-crit) decreases by 5.29%. MOSFET's LSC failure mechanism after electron irradiation is parasitic BJT conduction. Through TCAD simulation and theoretical derivation, it is proved that the increase of the base current is the main cause of parasitic BJT conduction, and the decrease of carrier lifetime will trigger parasitic BJT conduction earlier. The minority carrier lifetime can be reduced by 97% after electron irradiation. The influence mechanism of electron irradiation on SC characteristics is verified by TCAD simulation. The total ion dose effect will increase the SC peak current, and the displacement effect will significantly reduce the minority carrier lifetime, thus reducing the SC capacity of the device. The simulation results are consistent with the experimental results.

关键词： Doping   Photodiodes   Impurities   Lighting   Semiconductor device measurement   Logic gates   Chaos   Transforms   MOSFET   Transistors   infrared photodetectors   ion implantation  

摘要： Efficient p-type doping is at the top of the priority list for developing MoS2 electronics and optoelectronics devices due to MoS2 exhibiting the characteristics of an n-type semiconductor. However, implantation, a CMOS-compatible, controllable, and area-selective p-type doping process, is still unclear on MoS2 . Here, it is reported that the phosphorus-implantation (P-implantation), a part of the CMOS process, can achieve p-type doping and extend cutoff wavelength from similar to 980 nm to a value over 1550 nm selectively by modulating implantation dose. By tuning the implantation dose, it was able to transform MoS2 from semiconductor to semimetal. Besides, we fabricate a gate-controlled MoS2 photodiode with spectral response from 450 to 1550 nm by P-implantation. The photodiode has 24 times more responsivity and 500 times the special detectivity than pristine transistor and achieves the responsivity of 6.1 A/W at 1550-nm illumination. In summary, this study opens a guideline for commercialization of MoS2 chips and enriches the application scenarios of MoS2 in NIR photodetection.

关键词： 煤矿   全尺寸钻杆   动态加载   功率回收   液压系统   数据采集   PLC  

摘要： 【目的】为了模拟钻杆在煤矿井下瓦斯抽采钻孔过程中的真实受力情况，满足实物钻杆的疲劳试验需求。【方法】设计了一种矿用全尺寸钻杆动态加载系统，整个系统由钻杆加载平台、功率回收型液压泵站和测控系统3大部分组成，能够对不同规格的钻杆进行动态扭矩、轴向力和径向位移的复合加载。扭矩加载采用液压功率回收方式，由两个完全相同的液压马达和钻杆进行机械连接，主动马达带动钻杆和加载马达旋转，两者互为负载，加载马达将输出的流量反馈给主动马达，从而实现扭矩加载和功率回收，该闭环系统的能量损失由两个液压补偿泵进行弥补；轴向力和径向位移加载采用电液比例控制方式，由传感器采集各变量参数，PLC(programmable logic controller,PLC)对加载油缸的力和位移进行闭环调节，从而实现精确控制；试验过程中的各项运行参数和功率回收效率由测控系统进行数据采集并实时显示在上位机中。最后，采用?127×3 000 mm型外圆钻杆对系统的加载能力进行了试验验证。【结果和结论】结果表明：(1)加载系统的扭矩和转速可通过改变液压补偿泵的流量或压力，主动马达与加载马达的排量关系，变速箱档位等多种方式进行调节，能满足各种不同的试验工况。(2)当主动马达和加载马达的排量一致时，功率回收效率取得理论最大值77%。(3)在低速大扭矩工况下，实测的钻杆扭矩加载最大值为35 080 N?m，对应的转速为28 r/min，电机功率为50.7 kW，功率回收效率为66.2%，有效降低了加载系统的装机功率。研制的钻杆动态加载系统成功解决了现有矿用钻杆疲劳试验装置加载能力不足及耗能大的问题，为钻杆的测试研究工作提供了有力的设备支撑，具有显著的应用价值。

关键词： 多源融合   虚拟最优   TCN   Informer   功率预测  

摘要： 为解决光伏功率气象源数据质量不佳和来源单一所造成的预测精度不足问题，提出了一种基于TCN-Informer的多源融合虚拟最优气象预报源的光伏功率组合预测模型。首先，选取待预测电站临近气象站点，提取功率预报相关气象数据，筛选最佳气象因素；随后，通过数据融合构建光伏电站虚拟最优预报气象源，提高预测模型输入数据质量；最后，提出了一种基于TCN-Informer的功率预测模型，利用TCN的局部特征提取能力，对Informer提取的长期依赖关系和全局特征进行细化，实现光伏功率的精准预测。光伏电站实际算例验证表明，基于TCN-Informer的多源融合虚拟最优气象预报源光伏功率预测模型在4种不同天气类别下均具有较高的预测精度和较好的鲁棒性。

关键词： Resonant converters   Trajectory   MOSFET   Mathematical models   Light emitting diodes   Bridge circuits   Voltage   Switches   Zero voltage switching   Topology   Circulating current   LCC resonant converter   secondary-side phase-shift-control (SSPSC)   semisynchronous rectification (S-SR)   state trajectory model   wide gain range   zero-voltage switching (ZVS) turn-on  

摘要： Secondary-side phase-shift-control (SSPSC) is an effective method to widen the gain range of resonant converter with pulse frequency modulation (PFM). However, SSPSC not only induces a large circulating current through MOSFETs in secondary side semiactive bridge but also makes these MOSFETs operate under hard switching, thereby diminishing efficiency. To address these issues in this article, a semisynchronous rectification (S-SR) scheme is proposed, and it is realized on LCC resonant converter with SSPSC and PFM (SSPS-PFM LCC). This scheme will not conflict with SSPSC, can avoid circulating current flowing through body diodes of secondary side MOSFETs, and realize ZVS turn-on of these MOSFETs, thus improving efficiency. First, the concept of S-SR is proposed. Second, a time-domain state trajectory model of SSPS-PFM LCC is built. According to this model, the mathematical relation of S-SR conduction angle with switching frequency (SF) and secondary-side phase shift angle (SSPSA) is derived, and a simple calculation method of S-SR conduction angle is designed. This enables the realization of S-SR scheme with no additional sensors and almost no additional controller computational burden. Finally, a SSPS-PFM LCC prototype is built to verify the effectiveness of the proposed S-SR scheme.

关键词： 高频脉冲变压器   离子注入   电荷累积  

摘要： 随着离子注入技术的发展，用于离子源的电源也备受关注。为了解决离子注入过程中绝缘材料表面电荷累积的问题，设计了一款用于200 kHz离子源电源的高频脉冲变压器。采用AP法详细计算了变压器各参数，并根据参数计算结果采用两种不同绕制工艺制作了变压器，比较了两种不同绕制工艺下的输出波形。结果表明，原边疏绕、副边均匀密绕方式下输出波形较优，脉冲变压器输出参数符合实际工程要求。

关键词： 合成射流   声激励器   喷口直径   功耗   膜片振动   冲击传热  

摘要： 针对一个由特定型号扬声器和环形激励腔制备的合成射流声激励器,应用激光位移传感器、粒子图像测速仪和红外热像仪等测试方法,进行了声激励器输入功率和膜片振动、合成射流流场和冲击对流传热系列实验研究,以期揭示喷口直径（dc=2～10 mm）的综合影响.研究结果表明:恒定输入功率下,膜片在声激励器器件中的振幅相对于单纯扬声器情形存在不同程度的衰减,在小喷口直径和高激励频率下尤为明显;喷口直径为dc=6 mm的合成射流具有最大的喷吹速度、剪切涡量及其冲击对流传热系数.恒定膜片振幅下,小直径喷口合成射流相较于大直径喷口显示出更强的流动和冲击对流传热能力,但其在高激励频率下需要以付出更大的激励器输入功率为代价.声激励合成射流特征速度与激励频率的增加呈现线性增加的趋势,但激励器输入功率随激励频率的增加却呈现出非单调的变化;与单纯扬声器相比,对于小喷口直径的声激励器,对应于最小输入功率的激励频率向低频方向偏移.就本文的声激励合成射流而言,兼顾声激励器功耗和合成射流冲击对流传热特性,适宜的激励频率、喷口直径和无量纲冲击间距分别确定为f=250 Hz、dc=6 mm和H/dc=6～8.

关键词： FeFET   MFIS   MFISFET   MOSFET   analytical modeling  

摘要： The electrical characteristics of the ferroelectric field-effect transistors (FeFETs) are analyzed numerically and presented in this paper. The metal-ferroelectric-insulator-semiconductor field-effect transistor (MFISFET), among the primary structures, is taken into consideration. The nonsaturated hysteresis loop of the ferroelectric material is described by a novel analytical calculation for the relation of polarization against electric field (P-E). The combined impact of the nonuniform concentrations of electric field charge throughout the channel and the nonsaturated polarization of ferroelectric layers are considered to create a more realistic modeling. The proposed research work also provides an in-depth study of the electrical properties of the GAA-based Nanowire FeFET, exploring important variables including transconductance, subthreshold swing, as well as a threshold voltage. The analytical insights derived from the mathematical framework are consistent with the simulated results obtained with the ATLAS 3D simulator.

关键词： 差模频率   频率偏差   频率时空分布   共模频率   节点惯量  

摘要： 目前，电力系统频率的全局响应分析通常采用系统的共模频率。然而，随着新能源在电力系统中占比的不断提高，系统惯量降低和调频资源分布不均的特征日益明显。节点间频率偏差指标能够反映系统频率在时间、空间上的分布差异。为得到准确的节点间频率偏差测量值，文中提出一种功率量测法。该方法能够在机组内部结构和控制参数未知的条件下，通过测量功率波动得到系统的频率变化情况，从而分析系统的频率时空分布特征。首先，通过仿真模型得到节点间频率偏差分析系统受到扰动后的频率时空分布特征以及影响因素。然后，采用功率量测法得到频率偏差，并与锁相环、同步相量测量装置得到的节点间频率偏差进行对比，验证其准确性。最后，通过仿真和实验测试验证所提方法得到的节点间频率偏差能够有效体现系统频率的时空分布特征。