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关键词： 相互作用分析   同步环   功率平衡   带宽   线性化模型  

摘要： 由于跟网型变流器系统由控制主导、强耦合的特性，锁相同步与直流电容上功率平衡的关系并不清晰。为此，从带宽视角揭示了两者在带宽远离、接近时的交互机制。首先基于两者的动力学行为，以阻尼比和振荡频率作为前者的动态指标，以同步转矩和阻尼转矩作为后者的动态指标。之后利用奇异摄动理论将所建线性化模型在临界场景下进行代数化降维，通过分析动态指标的变化揭示了两者在带宽远离时的相互作用。其次基于功率平衡开环传递函数，分析锁相同步对功率平衡环节幅值裕度的影响，揭示了两者带宽接近时的相互作用。特别地，本文考虑了端电压控制的影响，发现其带宽降低会恶化两者间的相互作用，导致系统静态稳定极限减小，带宽接近易失稳的现象消失。

关键词： Voltage   Inductors   Capacitors   Topology   MOSFET   Voltage measurement   Transient response   Buck-boost   dc-dc converter   fast transient response   flying capacitor   hybrid converter   lithium-ion (Li-ion) battery   no right-half-plane zero   switched capacitor   three-fine-level buck-boost (3FLBB)  

摘要： This article presents a non-inverting three-fine-level buck-boost (3FLBB) hybrid converter suitable for lithium-ion (Li-ion) batteries. With seven power switches and two flying capacitors, the proposed 3FLBB converter produces the voltage of switching node between V-IN/2, V-IN , and 3 V-IN /2, which supports buck, boost, and buck-boost modes, and with smooth mode changes. Here, one of the two flying capacitors is used to drive the inductor (L), while another one is used to ensure that V-DS of each power switch is within 1/2V(IN) in all phases. Hence, the voltage stress of all the power switches is reduced to half-V-IN, and the normalized equivalent resistance and switching losses are greatly reduced by using two 1.8-V switches instead of two 5-V switches. Since the three modes all have buck-like operation, the average inductor current is reduced to always equal to the output current. Meanwhile, they all have continuous output current, similar complex pole pairs, and no right half-plane (RHP) zero, which enables fast load transient response. This design is implemented by only 1.8-V devices of a standard 0.18-mu m CMOS process, covering an input voltage range from 2.8 to 4.2 V. A 98.2% peak efficiency is measured at 2-MHz switching frequency with 2.2-mu H L, two 10-mu F mu F flying capacitors, and one 10-mu F output capacitor. It can deliver an output current of 50-1000 mA at a 3.3-V regulated output voltage. Moreover, the measured results show that this design achieves a significant improvement on undershoot and overshoot voltage than the previous works.

关键词： 变压器故障   电气试验技术   应用  

摘要： 本文从变压器的基本概况出发,详细探究了变压器的组成与类型,指出变压器在运行期间的常见故障,并阐述了变压器故障分析中几种常见的电气试验技术,以及每种电气试验技术的操作原理及注意事项,强调了电气试验对判定和分析变压器故障的重要作用.

关键词： SiON   NBTI   Reliability   Performance   MOSFET   Ring oscillator  

摘要： The impact of different SiON manufacturing processes on performance and reliability behaviors has been investigated for the MOSFETs. The performance of devices composed of an ultrathin SiON film fabricated by the novel low-temperature and low-pressure mild oxidation after the plasma solidification (LLMOPS) method can be enhanced compared to conventional processes, which is attributed to the increased mobility. It is observed from secondary ion mass spectrometry analysis that the distribution of nitrogen with the LLMOPS process moves toward the upper surface of SiON. As a result, the p-MOSFET manufactured by the LLMOPS process exhibits lower electrical performance degradation during the NBTI stress, indicating that a reduction in nitrogen concentration at the Si/SiO2 interface contributes to improving NBTI behavior. It is also demonstrated that the inhibition of NBTI phenomena enhances the frequency stability on the ring oscillator with circuit simulation. Thus, the LLMOPS process is a promising approach to improve the performance and reliability of MOSFETs in mass production.

关键词： 物联网技术   10kV   非接触式   电压互感器   检定系统  

摘要： 随着物联网技术的发展,非接触式电压互感器在电力系统中的应用越来越广泛.针对 10kV电压互感器的检定需求,本文设计了一种基于物联网技术的非接触式电压互感器检定系统.该系统通过利用物联网技术的优势,将各个检定点的数据传输和处理进行了高效优化和智能化.首先,本文详细分析了非接触式电压互感器的结构和原理.其次,提出了非接触式电压互感器检定系统与系统软件的总体设计方案,并设计了硬件总体方案与控制管理模型.最后,构建了一个实验平台来验证该系统的可行性和准确性.研究结果表明,基于物联网技术的 10kV非接触式电压互感器检定系统具有较高的准确性和可靠性.

关键词： 修正热路模型   油浸式变压器   绕组热点   温度计算  

摘要： 在输配电的过程当中,如果设备发生紧急故障,其自身拥有一定的保护功能也会随时启动,会自身切断与电网的其他联系,或者做出紧急跳闸,开启不供电功能.因此,为了保障电力系统正常工作,企业要安排专业的人员定期对相关设备进行评估,对设备做到实时监测.基于此,本文深入探讨了采用修正热路模型来计算油浸式变压器绕组热点温度的方法,以供参考.