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关键词： 超声测距   胶囊式   异常监测   油枕油位   变压器  

摘要： 针对现有监测方法在进行变压器胶囊式油枕油位异常监测时,存在监测到的油位误差过大,影响监测精度的问题,引入超声测距技术开展研究。利用超声测距,实现对变压器胶囊式油枕油位的测量。利用滤波器对监测信号进行处理,实现油枕油位异常的在线监测。通过仿真模拟实验证明,新的监测方法得到的监测结果误差仅在±0.02m范围内,具备极高的监测精度。

关键词： 35KV变压器   电磁与热耦合   设计优化   热稳定性   运行效率  

摘要： 随着电力行业的快速发展,变压器作为电力系统的核心设备其性能的可靠性与效率日益受到重视。在此背景下,针对35kV变压器,本研究通过电磁与热耦合的方法进行设计与优化,旨在提高变压器的运行效率与延长其使用寿命。首先,本文详细分析了变压器在工作时产生的电磁场分布特性及其造成的热效应,理论计算与有限元模拟相结合,建立了35kV变压器的电磁场与温度场的耦合模型。其次,通过模型仿真,评估了现行设计中存在的热点和效率瓶颈,针对发现的问题采取了优化措施,如改进冷却通道、调整线圈布局以及优化材料选用等。最后,优化方案经比较分析验证,结果显示温升控制在允许范围内,有效降低了热点温度,提高了变压器的热稳定性和电磁性能。此外,通过优化设计,变压器的总体能耗降低,运行效率有明显提升。本研究的优化策略不仅可以为35kV及同类变压器的设计提供科学指导,亦对提升变压器的性能和安全性具有重要的实际意义。

关键词： MOSFET   Degradation   Logic gates   Silicon carbide   Stress   Insulated gate bipolar transistors   Switches   Degradation location   reliability   short-circuit (SC)   traps   traps  

摘要： Degradation of SiC power mosfets under repetitive short-circuit (SC) stress is significant to the reliability of the power systems. A deep level transient spectrum method together with split C-V method to split the trap characteristics of the SiC mosfets is proposed. The degradation details of different locations in SiC planar gate (PG) and trench gate (TG) mosfets are comprehensively studied in this article. Thus, a criterion is provided to guide the SC degradation from the aspect of traps. The main degradation of the channel region is the increase of border traps for PG mosfet and newly generated interface traps for TG mosfet. The interface traps domain the degradation in the JFET region for both devices. The degradations of gate oxide for both devices affect the channel and JFET regions especially in the first set of SC cycles. The degradation of body diode is mainly influenced by hole traps in PG mosfet, but by electron traps first then hole traps newly generated in TG mosfet. Finally, the degradation locations of PG and TG mosfets are effectively characterized. It is the first time to use the trap measurement method to separate the different degradation in every part of the devices in detail. The method proposed in this article can better reflect the failure mechanisms related to dynamics and evaluate the operation of devices effectively, which provides very useful guidance for the reliability design and utilization of SiC mosfets.

关键词： Electronic circuits for signal processing   CMOS amplifier   Integrated circuits   MOSFET   g(m)/I-D methodology  

摘要： This paper presents the analysis and design of CMOS differential amplifiers using the first-order approach and sizing the transistors with the g(m)/I-D methodology. The design of four amplifiers using 130 nm CMOS technology is shown, and through spice simulation basic concepts of performance and compliance specifications are verified. The comparison of the performance of the designed amplifiers, in the synthesis of an active low-pass filter, is made to show that the fundamental performance parameters of each amplifier, affects the expected performance of the circuit under design, showing that the CMOS amplifier is not general purpose but that the application takes advantage of the characteristics of the amplifier or, alternatively, the amplifier is designed to meet the requirements of the application. Finally, while each architecture is sized using the same general performance specifications, it is also true that each has a specific and unique overall performance. These differences can be obtained and understood with spice simulation, since the resources of the simulation tool are used properly. All results obtained are at room temperature.

关键词： integrated circuit manufacture   MOSFET   nanofabrication  

摘要： In this letter, to improve the performance and reduce leakage currents of bulk low-temperature multi-layer SiGe/Si superlattice (SL) fin field-effect transistors (FinFETs), a p-type omega-shaped channel (Omega-channel) SL FinFET is realized by etching a Si/Si0.7Ge0.3 triple-layer stacked structure in a replacement metal gate (RMG) module on a silicon-on-insulator (SOI) substrate. In addition, a self-allied Ni0.9Pt0.1 silicide process and a low-thermal-budget (<= 400 degrees C) integration procedure were performed on the Omega-channel SL FinFET. Test results demonstrate that the on-state current (Ion) is increased by 5.5 times (from 78 to 429 mu A/mu m) and the off-state current (Ioff) is reduced by 78.8% (from 5.2 x 10-3 to 1.1 x 10-3 mu A/mu m) when compared with the corresponding currents of traditional bulk SL FinFETs.

关键词： MOSFET   power MOSFET   Schottky diodes   semiconductor device breakdown   semiconductor devices  

摘要： An improved 4H-SiC SBD-wall-integrated trench metal-oxide-semiconductor (SWITCH-MOS) with n-bury and split-gate is proposed. Under the premise of ensuring breakdown voltage (BV), the n-bury layer can smooth the path to current conduction, which reduces the specific on-resistance (RON, SP) and improves static characteristics. Besides, the split-gate is able to transform the gate-drain capacitance (CGD) and improve the dynamic characteristics. Therefore, a superior forward performance that SWITCH-MOS always craves is achieved. According to the simulation results, compared to the conventional SWITCH-MOS with almost the same BV, the proposed one reduces the RON, SP by 57% and the CGD by 59% while gaining equally advanced reverse performance. Its reverse conduction voltage is only -1.78 V, but its figure of merit reaches 1.67 GW/cm2 and 65 m OmeganC, which is attractive for the application in power inverters.

关键词： Switching loss   Semiconductor device modeling   Analytical models   Silicon carbide   Hysteresis   Numerical models   Switches   Analytical model   buck   dynamic   switching loss   threshold voltage instability   threshold voltage instability  

摘要： Accurate modeling of switching loss is critical for silicon carbide mosfets as well as power converters. However, previous "static" time-independent models did not consider the impact of gate oxide degradation on switching performance during long-term operation. This article proposes a "dynamic" time-dependent analytical model considering threshold voltage (V-TH) instability caused by gate oxide degradation to predict switching loss. The influence of V-TH instability on the turn-on and turn-off V-TH, as well as on switching loss during continuous operation is revealed first. Moreover, the problems suffered in the existing analytical model are investigated, and an improved switching loss model is presented. A measurement-based method to obtain the V-TH instability parameters for modeling is provided. Furthermore, a buck converter is built and operated under different conditions. Comparisons of switching waveforms and switching losses between experiments and the proposed model are given to validate the model. The results indicate that the proposed analytical model can effectively evaluate the switching loss, with an error within 7% under different continuous operating conditions. Finally, the universality of the proposed model for devices with different structures is verified, and a predication application of the model in operation is demonstrated.

关键词： Transistors   Couplings   MOSFET   Semiconductor device modeling   Logic gates   Capacitance   Electric potential   Timing   Silicon   Fluctuations   Back end of line (BEOL)   capacitive coupling   oxide semiconductor   2 transistor gain cell (2TGC)  

摘要： In this article, the impact of capacitivecoupling in the oxide-channel-based 2 transistor gaincell (2TGC) is evaluated. The study is performed using anexperimentally calibrated TCAD model of W-doped In(2)O(3)transistor (IWO MOSFET) in the mixed mode simulation.A write "0," read "0," write "1," read "1" (W0R0W1R1) oper-ation is performed and the storage node (SN) potential ismonitored. The SN is capacitively coupled to write and readwordlines (WWL and RWL), which temporarily lowers theSN potential after writing and during a read operation. Foran improperly designed 2TGC, capacitive coupling leads toa disturbed read for bit "0," and reduced sense margin forbit "1." To mitigate this problem,V-TH engineering, appropri-ate choice ofV(HOLD), and sizing of individual transistors ishelpful. To substantially suppress the capacitive coupling,a split gate (SpG) structure design for IWO MOSFET is pro-posed, which allows for a sizing-independent 2TGC designwith an undisturbed read and a higher sense margin thanthe traditional design.

关键词： Reliability   Fault trees   Analytical models   Motors   MOSFET   Hidden Markov models   Sensors   Operation principles   reliability evaluation   reliability model   switched reluctance motor  

摘要： This paper proposes an enhanced k-out-of-n:G model to assess the reliability of the dual-stator switched reluctance motor system (DSSRM). Firstly, the failure rates of power components are calculated as the basis for evaluating the system-level reliability. Then, traditional system-level reliability models, including fault tree and Markov models, are established. Subsequently, the proposed model is established based on the same predefined failure discrimination with Markov model, and the corresponding reliability calculation process is derived. The reliability of power converter in the DSSRM system is quantitatively compared based on the three models. The results indicate that the fault tree model yields overly conservative evaluations. And the proposed model almost maintains same results with the Markov model, and simplifies effectively the modeling and solving process. Finally, the experiments are developed to verify the validity of reliability assessment results.

关键词： Detection   gas spectroscopy   high-bandwidth   Gaussian beam   MOSFET   power coupling   quantum-cascade lasers (QCLs)   terahertz  

摘要： Monolithically integrated, antenna-coupled fieldeffect transistors (TeraFETs) are rapid and sensitive detectors for the terahertz range (0.3-10 THz) that can operate at room temperature. We conducted experimental characterizations of a singlepatch-antenna-coupled TeraFET optimized for 3.4 THz operation and its integration into an 8x8 multielement detector configuration. In this configuration, the entire TeraFET array operates as a unified detector element, combining the output signals of all detector elements. Both detectors were realized using a mature commercial Si-CMOS 65-nm process node. Our experimental characterization employed single-mode quantum-cascade lasers (QCLs) emitting at 2.85 and 3.4 THz. The 8x8 multielement detector yields two major improvements for sensitive power detection experiments. First, the larger detector area simplifies alignment and enhances signal stability. Second, the reduced detector impedance enabled the implementation of a TeraFET+QCL system capable of providing a-3 dB modulation bandwidth up to 21 MHz, which is currently limited primarily by the chosen readout circuitry. Finally, we validate the system's performance by providing high-resolution gas spectroscopy data for methanol vapor around 3.4 THz, where a detection limit of 1.6 x 10(-5) absorbance or 2.6 x 10(11) molecules/cm(3) was estimated.