教学课程资源库 更多>>

关键词： Gate driver   IGBT   loss   overshoot  

摘要： An 8-bit digital gate driver (DGD) using a half-bridge digital-to-analog converter IC and two power MOSFETs is proposed to enable the output voltage swing of +/- 15 V and the large gate current up to 28 A to reduce the switching loss (ELOSS) and the collector current overshoot (IOVERSHOOT) in a high-voltage, large-current IGBTmodule (HVIGBT) rated at 6500Vand 1000 A. By using the DGD to drive HVIGBT, the effectiveness of the active gate driving (AGD) is demonstrated for the first time in the world in the high-voltage and large-current range of 3.0-4.5 kV, 1000 A. The values of 1000 A, 4500V, and +/- 15Vare the world's highest records in AGD. For the purpose of investigating the optimum gate driving waveforms of AGD for HVIGBT, four different gate drive methods are compared in detail by measurements at 3.6 kV, 1000 A, and the stop-and-go gate driving is selected from a cost-performance perspective. Finally, a design guideline of AGD for HVIGBTs is clarified. The design guideline is to align the two peak heights of the collector current waveforms, thereby minimizing E-LOSS and IOVERSHOOT.

关键词： Nano-silver paste   graphene   low-temperature sintering   thermal resistance   gemini surfactant   IGBT  

摘要： Although high-power devices have experienced rapid development, they still suffer from several limitations in terms of traditional interconnecting materials. This paper describes the preparation of nano-silver paste through liquid-phase chemical reduction using PVP/12-3-12 type gemini quaternary ammonium salt as the mixed stabilizing agent. The high-thermal-conductivity multilayer graphene was mixed into the nano-silver paste to improve the interfacial heat-transfer performance of power devices. The nano-silver paste was sintered at a low temperature (270 degrees C), and its thermal properties were tested. The experimental results show that the thermal resistance of the sintered layers of different pastes decreases linearly with an increase in the loading of multilayer graphene under no-pressure sintering. When the loading of the multilayer graphene was 1%, the silver nanoparticles were adsorbed uniformly on the graphene nanosheets owing to the van der Waals force. Further, in comparison to pure nano-silver paste, the thermal resistance decreased by 60%. This shows that the uniform dispersion of multilayer graphene in the paste and its high thermal conductivity reduced the thermal resistance of the paste sintering layer, allowing the heat generated by the insulated gate bipolar transistor power chip to dissipate rapidly, improving the heat-transfer performance at the interface.

关键词： Gate-noise voltage   insulated-gate bipolar transistors   inverters   PIN diodes   reverse-recovery current   surge voltage  

摘要： This letter reveals the effect of the reverse-recovery current of a PIN diode on the surge and gate-noise voltages of an insulated-gate bipolar transistor (IGBT) in an inverter. Theoretical analysis reveals that the di/dt of the reverse-recovery current, the switching speed of the IGBT, and parasitic inductances affect the gate-noise voltage unlike a Schottky barrier diode because resonance does not occur due to junction capacitances. The analysis also indicates that the surge voltage may not occur when the dc voltage is increased even though a large amount of surge voltage occurs in a low dc voltage region. A 1-kV testing setup was designed and constructed using a 1.7-kV 260-A IGBT module, which confirms the validity of the theoretical analysis.

关键词： Insulated gate bipolar transistors (IGBT)  

摘要： A reverse conductivity insulated gate bipolar transistor (RC-IGBT) structure with no voltage bounce (snapback-free) on the back heterogeneous collector is proposed, an N-type layer is added as a high-resistance layer below the collector side field cut-off layer and the N+ collector region is partially replaced with a P-type thin layer of SiC material, and the collector resistance is increased by adding an N-type high-resistance layer, and a thin layer of P-type SiC material is used to form a heterogeneous collector on the back. It is guaranteed that the holes in the collector region can be injected in the first time during the initial conduction, eliminating the voltage bounce phenomenon, and at the same time, the device can quickly extract the excess carriers in the device when the reverse recovery occurs. The BHC RC-IGBT device has reduced the off-time by 314ns and the peak reverse recovery current by ***-3, reducing the reverse recovery time. Compared to traditional FS RC-IGBT, the shutdown time is shortened, the peak reverse recovery current is reduced by 20%, and the reverse recovery time is reduced by 25.1%. © 2023, The Authors. All rights reserved.

关键词： 带式输送机   驱动系统   变频器   永磁电机   低速大扭矩  

摘要： 变频+永磁电机的带式输送机永磁直驱系统具有效率高、可靠性高、维护工作量少、噪音低、驱动结构简单和起动性能好等优点,符合国家高效节能的低碳发展战略,是未来带式输送机驱动系统方向。然而永磁直驱电机由于自身具有低速大扭矩特点,带来电机体型偏大,给运输和安装带来不便,且永磁材料成本较高。针对永磁直驱电机体型较大问题,提出一种采用电机机壳水冷加电机定子线圈集中绕组的设计方案,同时对转子磁极结构进行优化,使得电机效率得以提高、体积得以减小,节约制造成本,方便电机运输与安装,提高永磁直驱方案市场竞争力。

关键词： 最大值原理   随机最优控制   Hamilton系统   双重倒向随机微分方程  

摘要： 本文基于实际金融问题,提出并进一步研究一类不确定模型下的倒向双重随机递归最优控制问题。首先提出在该模型中,代价泛函由sup_({Q∈Q})∫_(Θ)E[yθ(0)]Q(dθ)定义,其中{yθ(t),θ∈Θ}是由一组双重倒向随机微分方程的解组成的集合,再利用先验估计、线性化方法、Ito公式等方法,推导出该最优控制问题的最大值原理,进而最终给出该问题最优控制的必要条件和充分条件。

关键词： SiC薄膜   功率器件   制备工艺   MOSFET   IGBT  

摘要： 第三代半导体SiC因禁带宽、热导率高等优异性能得到广泛关注,SiC功率器件也成为学术界和工业界的研究热点。从SiC材料性质出发,归纳分析了SiC薄膜与SiC功率器件制备工艺,回顾了SiC MOSFET和IGBT器件的发展,讨论了SiC MOSFET和IGBT器件的结构设计优化和性能评估,最后指出SiC器件面临的挑战及发展趋势。

关键词： 拉格朗日乘数法   移相控制   回流功率优化   动态响应  

摘要： 针对DAB中存在的功率回流现象并以降低系统回流功率为目标,提出了一种基于EPS控制的回流功率优化控制策略。上述策略通过分析DAB的工作原理并运用KKT条件将约束条件转换为约束函数,然后建立拉格朗日多项式函数求极值,从而求得回流功率的最优解。同时,通过引入虚拟电压分量对变换器的传输功率进行实时估算与补偿,设计了一种直接功率补偿的控制方法,实现系统在突变情况下的快速响应能力。最后,仿真结果表明了所提优化控制策略优化回流功率的同时,也降低DAB的电流应力并改善其动态响应特性。