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关键词： 控制策略   模块化多电平换流器(MMC)   无源控制(PBC)   互联阻尼配置(IDA)  

摘要： 目前,大部分模块化多电平换流器MMC(modular multilevel converter)的控制技术将功率传输与环流抑制分别进行建模和控制,难以保证系统的全局稳定性。为此,将具有全局稳定性和强鲁棒性的互联阻尼配置无源控制IDA-PBC(interconnection and damping assignment passivity-based control)方法应用于MMC的控制器设计中。在两相静止坐标系下建立MMC的数学模型和端口受控哈密顿模型,推导了IDA-PBC控制器的表达式和控制参数范围,与其他MMC控制方法不同的是,IDA-PBC控制器可以在控制功率传输的同时实现环流抑制,并可以得到控制参数取值范围,进而能够综合分析控制系统的稳定性。最后,通过仿真研究验证了所提控制策略的可行性和有效性。

关键词： 导管消融术   心房颤动   聚类分析  

摘要： 目的 房颤是一组异质性较高的疾病,本研究拟通过聚类分析探讨房颤患者的不同亚型,并进一步评估不同的射频消融术式在不同房颤亚型中的成功率。方法 本研究回顾性纳入1 102例接受房颤射频消融的患者,基于59项基线变量进行层次聚类分析,并在聚类分析产生的房颤亚型间比较射频消融术后窦性心律转复的成功率。结果 基于层次聚类分析产生了5类房颤患者亚型:(1)较年轻房颤患者组(n=404);(2)较年长且合并慢病组(n=438);(3)窦房结功能障碍发生率较高组(n=160);(4)合并心衰组(n=80);(5)缺血性心肌病组(n=20)。在术后6个月随访时,亚型1(较年轻组)的消融成功率最高(81.2%),但亚型5(缺血性心肌病组)的消融成功率最低(65.0%)(P<0.05)。就早期消融成功率而言,与肺静脉隔离(pulmonary veins isolation, PVI)基础上复合异位病灶消融的广泛消融策略相比,仅在亚型2(较年长且合并慢病组)的患者中,单纯PVI与较高的消融成功率相关[79.6%vs. 66.5%;比值比(odds ratio, OR)=1.97,95%置信区间(confidence interval,CI):1.28~3.03]。结论 通过聚类分析产生的房颤亚型之间存在接受射频消融治疗效果的差异,聚类分析产生的亚组分型可为患者的个体化治疗提供一定的参考依据。

关键词： 持续质量改进   输液室   静脉穿刺   成功率  

摘要： 探讨FOCUS-PDCA模式在提高门急诊输液室静脉穿刺成功率中的应用效果。方法 选取2022年6月至 2023年6月在本院输液室进行输液的患者96例,按照FOCUS-PDCA模型实施时间分组,将2022年6月至2022年12月48名患者作为对照组(采用常规输液流程),2023年1月至2023年6月48名患者为观察组(在对照组基础上采用FOCUS-PDCA模式),比较两组患者一次性静脉穿刺成功率、输液不良事件发生率。结果 观察组患者一次性静脉穿刺成功率为95.8%,明显高于对照组(77.1%),差异具有统计学意义,P<0.05;观察组患者输液期间不良事件发生率低于对照组,差异具有统计学意义,P<0.05。结论 FOCUS-PDCA模式应用于输液室输液管理中,可提高一次性静脉穿刺成功率,减少相关并发症发生率,值得推广应用。

关键词： 边缘计算   电力机械设备   热稳定   潮流计算  

摘要： 为解决因电力变压器热稳定控制误差高、控制响应时间长的问题,提出一种基于边缘计算的热稳定控制方法。该方法引入边缘计算,将设备标准状态值设为边缘点值,估计电力变压器热稳定状态,以此估计值为基础,通过潮流计算获取温度变化影响值,结合温度变化影响值和热稳定状态估计,计算热稳定控制系数,设定热稳定控制阈值,通过阈值对比,完成电力变压器热稳定控制。实验结果表明,所提方法的热稳定控制误差和控制响应时间均较低,其具备了一定的可行性和有效性。

关键词： 有载分接开关   实时有载调压   终端用电质量  

摘要： 由于大量智能设备投入使用对供电质量的要求越来越高,电网现有的供电电压波动较大,满足不了终端用户的需求。针对现有供配电的不足,开发一种在10kV干式变压器加装有载分接开关的新型调压技术,实时有载调压,改善终端用电质量,从而达到输出电压在设定的范围内稳定运行,起到保护用电设备和节能的效果。

关键词： 高功率   窄线宽光纤激光   相干合成   光谱合成  

摘要： 高功率光纤技术是目前发展最为迅速的激光技术之一,其在通信、科研、工业、国防等领域有着卓越表现。通过对激光技术发展的研判,上海光学精密机械研究所在国内率先开展光纤激光技术的研究,其中的关键技术主要为高功率窄线宽光纤激光技术和高功率光纤激光合成技术。针对光纤激光的特点,在高功率窄线光纤激光方面,为了抑制非线性效应,逐渐凝练出单频种子光谱调控结合多级放大技术,该技术能够在单光纤激光器功率放大的同时,保持线宽不变并最小化光束质量的劣化。在高功率光纤激光合成方面,同样结合光纤激光的特点,率先开展了全光纤环形腔相干合成(CBC)技术和光谱合成(SBC)技术的研究。近年来,上海光学精密机械研究所在一系列关键技术方面取得了突破性进展,并取得了一系列重要成果。这些成果推动了高功率光纤激光技术的推广和应用,使其成为目前国内外实现高能光纤光源的主流技术。

关键词： Logic gates   Silicon carbide   MOSFET   Voltage control   Voltage   Switches   Transistors   Gate drivers   series connection   silicon carbide   voltage balancing  

摘要： The versatility of half-bridge configuration of silicon carbide (SiC) metal-oxide-semiconductor field-effect transistor (mosfet) power module contributes to its widespread adoption, highlighting the popularity and significance of its corresponding dual gate driver (D-GD) design. For use in high-voltage converter designs, configuring the half-bridge module as series connection with effective voltage balancing (VB) can make it aggregated into a single device with double voltage rating. Hence, in this letter, a novel active VB scheme with seamless integration into D-GD is proposed. Different from existing passive VB methods with significant loss and active VB strategies with high cost and complexity, the proposed active VB circuitry only consists of few low-voltage and low-power bipolar junction transistors (BJTs), resistors, and capacitors, which offers the prominent advantages of ease of implementation and integration, low cost, and high reliability. Analysis is provided to illustrate the working principle, followed by the criterion for parameter selection. Finally, the experimental results based on a 3.3-kV half-bridge SiC mosfet power module are given to demonstrate operational performances.

关键词： GaN   MOSFET   vertical device   resistance partitioning  

摘要： In this work, fully vertical GaN trench MOSFETs were fabricated and characterized to evaluate their electrical performances. Transistors show a normally-OFF behavior with a high I-ON/I-OFF (similar to 10(9)) ratio and a significantly small gate leakage current (10(-11) A/mm). Thanks to an improved resistance partitioning method, the resistances of the trench bottom and trench channel were extracted accurately by taking into account different charging conditions. This methodology enabled an estimation of the effective channel and bottom mobility of 11.1 cm(2)/V center dot s and 15.1 cm(2)/V center dot s, respectively.

关键词： Body diode   reverse recovery   Schottky contact   superjunction MOSFETs (SJ-MOSFETs)  

摘要： In this article, we demonstrate the experimental results of a 650-V superjunction MOSFET (SJ-MOSFET) featuring dual Schottky contacts at the source side to reduce the reverse recovery charge (Q(rr)) of its body diode. The n-type Schottky contact suppresses the operation of the p-n junction, and the p-type Schottky contact lowers the hole injection efficiency further. Both of them reduce Q(rr). According to the experimental results, Q(rr) of the proposed SJ-MOSFET (1.4 mu C) is 20.5% of that of the conventional device (6.8 mu C) and 38.9% of that of the device with only n-type Schottky contact (3.6 mu C). The forward voltage drop of its body diode is 0.91 V, which is 0.07 V higher than that of the conventional device and 0.09 V higher than that of the device with only n-type Schottky contact. These characteristics make it be suitable for high-speed switching applications.

关键词： MOSFET devices  

摘要： The adverse effects of leakage currents and short channel effects (SCE) on mobility degradation in CMOS technology below the 100-nanometer scale. To mitigate these effects, the paper suggests using material engineering techniques to improve the mobility of charge carriers and control SCE effects. Specifically, the switching characteristics of a dual-gate MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) are enhanced by stacking the gate with various oxide layers including SiO2, HfO2, and TiO2. These oxide layers possess a range of permittivity capabilities from low to high. By combining different oxide layers the proposed device aims to improve its performance. To evaluate the performance of the proposed device we have employ simulation models such as CONMOB (Concentration Dependent Mobility), AUGER (Auger Recombination), and FLMOB (Field Dependent Mobility). These techniques help to obtain the accurate and reliable simulation results. We have utilized the parameters like drain current, transconductance, electric field, ION, IOFF, and ION/IOFF and simulate them using the Silvaco TCAD tool. The analysis of these parameters are discussed in the paper we have highlighted the compatibility of the proposed DGMOSFET device for low-power applications. In this paper, we have focus on the improving the switching characteristics of a dual-gate MOSFET by utilizing gate stacks with various oxide layers. The proposed device is evaluated through simulations using concentration-dependent mobility, Auger recombination, and field-dependent mobility techniques. The results indicate that the device is suitable for low-power applications.