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关键词： Power MOSFET  

摘要： The parallelling of power semiconductor devices is essential for desired current ratings and the system is prone to the current unbalancing due to parameter variations. SiC devices with significant variable threshold voltage due to manufacturing yield and temperature distribution have a consequential possibility of dynamic current unbalancing. This paper presents the peak detection-based current balancing of parallel-connected SiC devices to minimize the turn-on and turn-off current unbalancing. PCB current sensors are used for the measurement and feedback of the signal for this peak detection-based current balancing mechanism.

关键词： Threshold voltage  

摘要： This paper proposed an 8 nm N-type Double Gate MOSFET with improved characteristics. A comparative study has been done based on substrate and oxide material. The substrate and oxide material combination is Si-SiO2, SiGe-HfO2. This study discussed about which channel and oxide material is performed with better efficiency in sub-micron dimension in terms of Ioff, Ion, Ion/Ioff, Threshold Voltage (Vth), Sub-threshold Swing (SS) and Drain-Induced-Barrier-Lowering (DIBL) to obtain energy efficient and high performance circuits. All parameters are validated according to the IRDS-2020 and compare with existing literature. Based on improved performance SiGe material has been chosen for circuit level applications. In this research all the basic gates (NOT, AND, OR, XOR, XNOR) as well as universal gates (NAND, NOR) along with their performance with respect to Propagation Delay, Short Circuit power dissipation, Dynamic power dissipation, Power Delay Product (PDP), Energy Delay Product (EDP) and Noise Margin have been explored at 1 Volt supply voltage. These findings suggest that the proposed device is a suitable candidate to design high speed and low power logic circuits.

关键词： HEMTs   Heating systems   Thermal management   Electronic packaging thermal management   Thermal resistance   Substrates   Photonic band gap   Logic gates   MOSFET   Conductivity   Ga2O3   GaN   power devices   thermal management   wide bandgap (WBG) semiconductor  

摘要： Wide bandgap (WBG) and ultra-WBG (UWBG) semiconductor devices exhibit superior performance with higher breakdown voltage and lower ON-resistance compared to Si-based devices, rendering them highly competitive in the field of electric energy conversion and communication. Especially, GaN, as one of the representative materials in WBG semiconductors, has progressed to the stage of industrial realization, and the new generation of UWBG semiconductors such as Ga2O3 has become a popular research focus in the last decade for power electronics applications. However, the primary challenge faced by these advanced semiconductor devices is thermal management, particularly in high-power application, which leads to a serious degradation in electrical performance and long-term reliability. Therefore, there is an urgent need for effective thermal management technologies. This review comprehensively summarizes recent advances in device-level thermal management techniques for WBG and UWBG semiconductors, ranging from internal device structure optimization to a series of external strategies for enhancing thermal diffusion. These strategies include enhancing the internal thermal dissipation through device architecture optimization, substrate thinning, high thermal conductivity substrate bonding and coverage, flip chip package, active method of microchannel cooling, and transient thermal management techniques. Finally, we discuss the existing technical challenges, potential solutions, and further development opportunities in thermal management techniques, with the aim of addressing the critical thermal dissipation issue to facilitate the further industrialization of WBG and UWBG semiconductors.

关键词： Hidden Markov models   Modulation   Voltage control   Harmonic analysis   Topology   Silicon carbide   Pulse width modulation   MOSFET   Voltage   Silicon   Circulating current suppression   efficiency improvement   hybrid-frequency   hybrid modular multilevel converter (MMC)   multimaterial devices   redundant voltage level  

摘要： The hybrid modular multilevel converter (HMMC) based on multimaterial devices has been proved to achieve a better balance among cost, loss, and feasibility compared with others. However, due to the use of hybrid-frequency modulation method, the implementation of traditional circulating current control strategy would increase output voltage harmonics of the HMMC. In this article, the mechanism of the above problems is analyzed in detail, and the specific circulating current suppression (SCCS) method is proposed. Based on the voltage balancing operation of the high-frequency submodules, the corresponding redundant voltage generated by the low-frequency submodules in the arms is analyzed. By utilizing the redundant voltage levels during the operation of HMMC, the number of inserted submodules is adjusted to reduce the circulating current of the system without compromising the quality of the HMMC output waveform. Finally, the simulation and experimental results verify the effectiveness and feasibility of the proposed SCCS method.

关键词： Ga2O3   MOSFET   superjunction   self-biased   specific on-resistance   breakdown voltage  

摘要： In this article, a high-performance enhancement-mode (E-mode) lateral superjunction (SJ) beta-Ga2O3 metal-oxide-semiconductor field-effect transistor (MOSFET) incorporating a self-biased p-type nickel oxide (NiO) layer was proposed and numerical investigated. The drift region of the proposed lateral SJ Ga2O3 MOSFET includes n-type Ga2O3, Al2O3 and p-type NiO layers. The electric field distribution and specific on-resistance of the drift region both are greatly improved, due to the compensation effect n-type Ga2O3 and p-type NiO SJ drift layers. Additionally, the p-type NiO layer is self-biased with a voltage of -14.3 V, to form an accumulation layer in the drift region, which further reduces the specific on-resistance (R-on,R-sp) of the device. Simulation results indicated that the proposed device achieves a breakdown voltage (BV) of 7000 V and R-on,R-sp of 17.73 m Omega cm(2). In contrast, the conventional device with the same drift region length has a BV of 3500 V and R-on,R-sp of 162.58 m Omega cm(2). The figure of merit values for the proposed and conventional devices were 2.76 GW cm(-2) and 75.34 MW cm(-2), respectively, representing a 3565% improvement. The combination of superior device performance and a straightforward manufacturing process presents a promising outlook for the application of the proposed device.

关键词： 海上升压站   主变压器   安装调试技术   交接试验  

摘要： 本文分析了海上升压站主变压器的安装与调试工艺,重点探讨了其在恶劣海洋环境下的特殊技术要求,包括机械特性、防护性能和空间优化。文章详细介绍了安装前的准备、运输吊装、本体就位、附件安装及绝缘油处理等关键步骤,并系统阐述了交接试验、充油检查、保护系统调试和试运行等调试工艺。通过优化技术流程,旨在提升主变压器运行可靠性,降低维护成本,为海上风电行业的高效发展提供支持。

关键词： Electric fields   Logic gates   Silicon carbide   MOSFET   Resistance   Performance evaluation   Numerical models   JFETs   Epitaxial layers   Epitaxial growth   Breakdown voltage (BV)   gate oxide robustness   periodical bottom shielding   silicon carbide (SiC) trench MOSFET  

摘要： In this article, a silicon carbide (SiC) trench MOSFET with periodically grounded p-type shielding region (P+SLD) at the trench bottom (PGP-TMOS) is designed and experimentally demonstrated. There exist deep-implanted P+ (DP) regions on both sides of the trench and the P+SLD is grounded by connecting to the DP region periodically. Therefore, the PGP-TMOS owns two different schematic cross section views. The P+SLD and DP region together improve the robustness of the gate oxide. A current spreading layer (CSL) by epitaxy is introduced to improve the device performance. Numerical 2D-simulation results show that compared with the trench MOSFET with floating P+SLD (FP-TMOS), the peak electric field in the gate oxide (E-ox,E-peak) is decreased by 50.77% while the breakdown voltage (BV) and specific ON-resistance (R-on,R-sp) keep almost the same. In addition, the PGP-TMOS demonstrates superior switching characteristics. The PGP-TMOS has been manufactured on different wafers. When single epitaxial wafers are used, BV of the samples is only 1300 V and the conduction characteristic is poor due to the junction field-effect transistor (JFET) effect and ion implantation scattering. BV and R-on,R-sp are improved to 1570 V and 5.96 m Omega & sdot;cm(2), respectively, when the PGP-TMOS is manufactured on wafers with a CSL layer introduced by epitaxy. BV and R-on,R-sp are improved by 20.77% and 91.85%, respectively, compared with the former ones. Moreover, the influence of the key parameters on the PGP-TMOS is discussed, which provides guidance for subsequent optimization.

关键词： 风电功率预测   可解释性   堆叠模型   特征优化   集成学习  

摘要： 鉴于当前风电功率预测算法在堆叠建模过程所存在试错性与弱解释性问题,提出一类应用于风电功率预测的可解释性优化堆叠模型(interpretable optimal stacking model,IOSM)。首先,建立初始冗余基学习器并进行特征权重解释;其次,构建一个综合衡量模型性能与计算代价的特征优化度量,优化关键特征并训练形成优化后的基学习器;最终,根据特征优化度量对基学习器进行优化选择,搭建得到元学习器。经如上步骤,即完成搭建IOSM。所提算法在广西典型风电场的算例表明,IOSM相对于最优单一模型的RMSE与MAE指标上分别降低13.01%和18.23%;相对于其他各类主流组合预测算法,该文算法在RMSE与MAE指标分别降低8.24%与10.28%的同时,至少降低了142.38%的建模计算代价。所提算法的有效性及先进性得到验证,为风电功率预测的可解释性优化建模上提供了新的思路与方法。

关键词： 固体氧化物燃料电池   涡轮发动机   混合动力   神经网络   功率匹配   多目标优化  

摘要： 针对航空固体氧化物燃料电池（SOFC）和涡轮发动机（GT）混合动力系统的功率匹配问题，提出1种基于神经网络的多目标优化方法。通过数值仿真，分析了不同SOFC与GT功率分配对系统性能（系统总质量、系统热效率、系统发电效率、燃油消耗率、CO2排放率等）的影响。采用BP神经网络代理模型，对不同功率匹配方案进行了性能预测，并结合多目标遗传算法与TOPSIS决策方法，优化得出了最佳功率匹配方案（SOFC输出功率为133.092 kW，GT输出功率为66.908 kW）。研究结果表明，优化后的功率匹配方案系统总质量为117.124 kg、燃油消耗率为0.196 kg/s、系统热效率为73.21%。相较于SOFC和GT功率输出相等的方案，优化后的方案系统总质量降低了27.7%。该方法为航空混合动力系统的功率匹配优化设计提供了1种新的思路。