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关键词： Silicon carbide   MOSFET   Silicon   Doping   CMOS process   Threshold voltage   Temperature measurement   Logic gates   Performance evaluation   Low voltage   CMOS   high temperature   TCAD   channel mobility   SiC/SiO2 interface  

摘要： SiC-based n-channel and p-channel MOSFETs fabricated by Fraunhofer IISB SiC CMOS technology are characterized from room temperature up to 300 degrees C. The behaviors of these low voltage devices including the short-channel effect (SCE), p-type ohmic contact with high resistivity, and the low channel mobility due to the SiC/SiO2 interface are presented. A thorough analysis is performed to understand the cause of low channel mobility, with TCAD simulations specifically on p-channel MOSFET, providing an insight into the impact of channel length, interface traps, and contact resistivity on device performance. The analysis in this paper is important in the comprehension of the low-voltage SiC MOSFETs so as to achieve balanced n-channel and p-channel MOSFETs and lead to the monolithic integration of SiC ICs with SiC power devices.

关键词： MOSFET devices  

摘要： Junction temperature is a critical silicon carbide (SiC) semiconductor parameter for thermal management and health condition monitoring. To monitor the junction temperature, the temperature-sensitive electrical parameter (TSEP) method is gaining increasing attention. Among the TSEPs of the SiC mosfet, the turn-off delay time has good linearity over a wide temperature range. However, the temperature sensitivity of the turn-off delay time of SiC mosfet is low. In existing solutions for turn-off delay time, the gate drive resistance is increased to prolong the turn-off delay time and enhance the temperature sensitivity, affecting the switching process of the device under test (DUT) and increasing switching loss. To address these challenges, a novel real-time junction temperature monitoring method is proposed for turn-off delay time. The proposed method amplifies the temperature sensitivity of the turn-off delay time without increasing the gate drive resistance. The gain of the temperature sensitivity amplification can be easily adjusted by changing the detection circuit parameters. According to the test results, the temperature sensitivity of the turn-off delay time is successfully amplified by the detection circuit with a gain of 60.90331 (which is close to the setting value of 61), without affecting the switching process of the DUT. Once the DUT is turned off, the detection circuit can detect the turn-off delay time and output a wide pulse signal, whose pulse width exhibits good linearity and high temperature sensitivity over a wide temperature range, allowing it to be directly tested by a microcontroller. © 1986-2012 IEEE.

关键词： Capacitors   Silicon carbide   MOSFET   Logic gates   Discrete cosine transforms   Threshold voltage   Gate drivers   Optical switches   Equivalent circuits   Clamps   Active clamping   medium voltage   power devices   series-connection   SiC MOSFETs  

摘要： This paper proposes a control method for balancing the voltages of series-connected SiC MOSFETs based on active clamping and comparison circuitry. Each SiC MOSFET is paired with an active clamping module (ACM), which comprises an auxiliary switch and a capacitor. Equal voltage distribution across the SiC MOSFETs is achieved by maintaining balance among the voltages of the ACM capacitors. This voltage balance is achieved through a local comparison circuit with the threshold set at the blocking voltage of the SiC MOSFET in its OFF state. When the ACM capacitor voltage exceeds this threshold, the auxiliary switch is triggered on during the dead time, and the excess energy of this capacitor is recycled back to the DC bus. The proposed adaptive balancing process maintains all ACM capacitor voltages at the threshold without requiring system-level coordination or communication between ACMs, thus simplifying the control circuits. The method does not affect the SiC MOSFETs' switching speed and enables zero-voltage switching on for the auxiliary switches. Comprehensive operating principles and key parameter designs are provided for both DC transformer (DCT) and Voltage Source Converter (VSC) applications. A high-voltage power module, incorporating six SiC MOSFETs in series, was constructed to demonstrate the effectiveness of the proposed approach. Tests on a DCT and a VSC incorporating this high-power module validated the efficacy of the proposed voltage balancing method.

关键词： Copper   Electronic packaging thermal management   Thermal resistance   Temperature measurement   MOSFET   Thermal conductivity   Electrical resistance measurement   Surface resistance   Packaging   Current measurement   Dr.MOS package thermal performance   clip thickness   clip material   attachment material   coating  

摘要： This study explores the impact of copper clip design on the thermal performance of driver MOSFET (***) packages with the goal of optimizing heat dissipation efficiency in microelectronic components. The study examines four key variables: clip thickness, material, attachment material, and plating material. The experimental results show that increasing the clip thickness from 0.15mm to 0.2mm leads to a 2.1% reduction in thermal resistance (from 3.3667 degrees C/W to 3.2958 degrees C/W). Furthermore, using copper C1100, which has higher thermal conductivity (391 W/m-K), further reduces thermal resistance, improving overall heat dissipation. Additionally, employing high-conductivity adhesives like SAC305 improves the thermal interface between the clip and wafer, while coatings such as graphene enhance thermal stability and corrosion resistance. Under high-voltage conditions (12V and 19V), the package with thicker copper clips and better attachment materials exhibited a significant reduction in surface temperature, dropping from 93.3 degrees C to 71.7 degrees C at 12V. These findings offer valuable insights for enhancing the thermal management efficiency of *** packages, ensuring better reliability and longevity in high-power applications.

关键词： 高功率微波防护   柱状等离子体阵列   时间序列模型   Encoder-Decoder框架   multivariate attention机制  

摘要： 柱状等离子体阵列（columnar plasma array, CPA）被证明是一种极佳的高功率微波（high-power microwave, HPM）防护手段。然而，并非任一的HPM都足以激发CPA产生电磁屏蔽效应，因此提出并实现一种新的基于Encoder-Decoder框架和multivariate attention机制的时间序列模型iiTransformer（improved iTransformer）,对HPM与CPA间的复杂非线性过程进行数学建模并实现高功率微波反演。使用有限元方法（finite element method, FEM）完成算法仿真和数据采集，分别使用iiTransformer模型和ResNet-18模型实现了对高功率微波的反演推断。在iiTransformer模型中，利用Encoder和Decoder架构分别对数据序列和目标序列进行了多头自注意力处理，用于提取多变量在多通道中的关系依赖。相比之下，ResNet-18模型拟合数据序列所映射出的热图与目标序列间呈非线性映射关系。研究结果表明，所设计的iiTransformer模型具有很强的表征学习和非线性拟合能力，不仅泛化能力强而且鲁棒性好，在训练集上的损失为3.4548×10-7,在验证集上的损失达到了1.804×10-7,在测试集上的准确度为99.923%,远远高于ResNet-18模型的反演精度。

关键词： HEMTs   Logic gates   Gallium nitride   Low voltage   MOSFET   Semiconductor lasers   Resistance   Reliability   Optical switches   Lasers   Direct-drive depletion-mode (DDD) GaN device   low voltage GaN HEMT   wide bandgap (WBG) power semiconductor devices   pulse laser driver   switch-controlled (SC) short pulse laser  

摘要： This paper proposes a short-pulse laser driver using direct-drive depletion-mode gallium nitride high-electron-mobility-transistor (DDD GaN HEMT) device. Known for its low on-resistance, high switching performance, normally-off operation, and reliability, DDD GaN devices are becoming popular in power applications. In this work, an in-house D-mode GaN HEMT with a blocking voltage of 200 V and on-resistance of 18 m ohm is used in a short-pulse laser driver for the optical phased array (OPA) applications. To achieve higher spatial resolution, the laser repetition rate must be in the tens of MHz range. Therefore, the dynamic behavior of device is first characterized by the double-pulse test. Additionally, the push-pull based laser driver actively controls the load capacitor charging time and the laser pulse width, thereby ensuring stable operation at high repetition rates. The output characteristics of switch-controlled (SC) short-pulse laser driver are simplified to switch turn-on time, stray inductance, and the input voltage. Finally, the experimental results achieved a short pulse width of less than 5 ns, high repetition rate of 50 MHz, propagation delay of less than 1.5 ns and peak power of 175 W, meeting the requirements for the specified object detection application.

关键词： 风电并网   智能调节终端   运行广义短路比   边缘计算   功率调节  

摘要： 随着风力发电技术快速发展，如何提高风电最大化消纳水平的同时又保障电网系统的可靠运行已成为亟需解决的问题。首先分析了能够反映新能源以任意功率并网时电网强度的运行广义短路比，以及边缘计算所具有的优势；其次设计了一种计及运行广义短路比的风电并网功率智能调节终端，给出了其具有的功能、整体构成和信息采集通信方案，进而研究了风电并网功率调节策略；最后通过试验对所给终端功能和调节策略进行了验证。结果表明，该智能调节终端能够可靠、快速对不同并网点功率进行调节，对并网功率越限进行告警，对保障电网系统强度、提高系统抵御风电并网功率波动能力具有一定的实际借鉴价值。

关键词： 高功率   线偏振   光纤激光   研究进展  

摘要： 线偏振光纤激光在光束合成、非线性频率变换等领域中有着广泛的应用。从激光线宽、工作波段、运行体制、功率定标放大新动向等多个维度梳理了国内外线偏振光纤激光的研究成果及发展脉络，并对线偏振光纤激光的发展趋势进行展望。

关键词： 水田   农业机械   自动驾驶   卡尔曼滤波器  

摘要： 针对水田自动驾驶农机遇到侧滑时速度突变导致转角估计不准确的问题，本文提出了一种基于双观测值融合卡尔曼滤波器的水田作业农机转向轮角估计方法，建立了水田作业农机转向轮角估计模型。首先采用改进型两轮农机侧滑模型获得基于运动学模型的水田农机前轮转向角度，其次对所采集的GPS速度和惯性导航速度采用加权观测融合的方法对转向模型的水田农机作业速度进行补偿，最后提出了基于双观测值融合卡尔曼滤波器的水田作业农机轮向轮角估计方法，将基于运动学模型的前轮转向角和基于转向电机编码的前轮转向角作为双观测值，从而估计水田农机前轮转角。为验证本文所提方法，以水稻直播机为研究平台，在水田中开展速度校正、前轮转向角估计试验和直线跟踪试验。速度校正试验结果表明，水田硬底层高低不平是前轮转角拟合精度不佳的直接原因，本文所提方法将直播机速度稳定在一定范围内，解决了因水田硬底层起伏变化造成前轮转角拟合精度不佳的问题。前轮转向角估计试验结果表明，农机前轮估计角度相对角度传感器角度变化跟踪误差平均值为0.12°,偏差最大值为1.67°,偏差标准差为0.4°。本文所提方法能够准确地测量农机前轮转向角，最终控制直播机稳定追踪目标角度，满足水田农机前轮转角估计精度要求。直线跟踪试验结果表明，在水田环境下，平均绝对误差为3.14 cm,位置偏差标准差为2.11 cm。本文提出的方法适用于水田无人驾驶，提高了转角估计精度和农机导航作业质量。

关键词： Silicon carbide   MOSFET   Semiconductor device modeling   Integrated circuit modeling   Mathematical models   Transient analysis   Logic gates   Switches   Computational modeling   Accuracy   Real-time simulation   FPGA   power electronic converter   SiC MOSFET   transient model  

摘要： This article proposes a silicon carbide (SiC) MOSFET transient model on the field programmable gate array (FPGA), which is suitable for the real-time simulation (RTS) of power electronic converters. The model describes the transient process with state equations, which is segmented by the time-scale, and achieves accurate simulation results with small time-step. Compared with the existing research that simplifies SiC MOSFET model in the RTS implementation process, the proposed modeling method not only considers the hard-switching process caused by insufficient deadtime, and the special switching mode that the channel turn-off precedes the antiparallel diode turn-on in opposite device, but also fits the nonlinear characteristics of the SiC MOSFET through look-up tables (LUTs). In addtion, the parallel solution structure of the FPGA-based RTS model is completed through hardware optimization design scheme. Combined with circuit decoupling technology, the model can be solved by the Backward Euler (BE) discretization method with time-step of 10 ns. Subsequently, the effectiveness and accuracy of the modeling method are validated by the simulation and hardware experiments.