An improved perturbation technique proposed in a recent paper (Int. J. Electronics, vol. 63, pp.403-414) has been successfully applied to steady-state analysis of PWM switching converters. This paper extends the algor...An improved perturbation technique proposed in a recent paper (Int. J. Electronics, vol. 63, pp.403-414) has been successfully applied to steady-state analysis of PWM switching converters. This paper extends the algorithm to transient analysis of a broader class of non-linear systems. As an example, the transient response of a Boost PWM switching converter is analyzed to demonstrate its simplicity and accuracy.展开更多
The analysis of the impulse voltage on the internal electric field of the cable joint plays a key role in studying the breakdown of the joint. Based on the finite element method, a three-dimensional electromagnetic fi...The analysis of the impulse voltage on the internal electric field of the cable joint plays a key role in studying the breakdown of the joint. Based on the finite element method, a three-dimensional electromagnetic field simulation model of the cable joint is established in this paper. Simulation results show that the voltage at the head of the cable joint reaches about twice the impulse voltage. The increase of the conductivity of semi-conductive material also leads to the increase of electric field intensity. Then, several points and curves at different positions are selected for further analysis in this paper. Among them, the electric field distortion at the edge of the high voltage shield is the most serious and the electric field in the air gap is the least.展开更多
针对变流器不同位置杂散电感准确获取困难的问题,提出一种基于LC高频振荡原理的杂散电感多参数提取方法,充分利用变流器自身结构,通过3个现场实验主动构建不同的谐振电路,并根据它们的振荡频率计算变流器不同位置的杂散电感。首先阐述...针对变流器不同位置杂散电感准确获取困难的问题,提出一种基于LC高频振荡原理的杂散电感多参数提取方法,充分利用变流器自身结构,通过3个现场实验主动构建不同的谐振电路,并根据它们的振荡频率计算变流器不同位置的杂散电感。首先阐述了高频振荡法的基本原理,建立了不同谐振实验的等值电路模型。然后,以1700 V/450 A IGBT变流器系统为例,通过仿真与实验进行了可行性与有效性验证。最后,通过实验与传统双脉冲法进行了对比分析。研究表明:所提出的方法可有效提取变流器内不同位置的杂散电感参数,与双脉冲法提取开关杂散电感结果基本一致,精度可达纳亨级。展开更多
切换试验是考核有载分接开关(on-load tap changer,OLTC)长期运行可靠性的重要试验项目之一。为解决现有切换试验回路试验周期长、试验成本高等问题,该文开展OLTC高效切换试验技术研究。首先,提出一种满足多台OLTC切换的切换试验回路,...切换试验是考核有载分接开关(on-load tap changer,OLTC)长期运行可靠性的重要试验项目之一。为解决现有切换试验回路试验周期长、试验成本高等问题,该文开展OLTC高效切换试验技术研究。首先,提出一种满足多台OLTC切换的切换试验回路,分析回路参数对试验结果的影响;其次,基于ATP-EMTP进行不同OLTC数量和不同试验方案的仿真分析,提出高效切换试验的试验方案。最后,采用2台不同类型OLTC,按照“一前一后”切换的试验方案,对切换试验回路进行验证。结果表明,该试验回路在多台OLTC进行切换试验时也能满足试验条件,达到了OLTC高效切换试验的需求,可为OLTC高效切换试验提供有益参考。展开更多
基金Natural Science Foundation of Guang Dong ProvinceDoctoral Fund of the State Education Commission of China
文摘An improved perturbation technique proposed in a recent paper (Int. J. Electronics, vol. 63, pp.403-414) has been successfully applied to steady-state analysis of PWM switching converters. This paper extends the algorithm to transient analysis of a broader class of non-linear systems. As an example, the transient response of a Boost PWM switching converter is analyzed to demonstrate its simplicity and accuracy.
文摘The analysis of the impulse voltage on the internal electric field of the cable joint plays a key role in studying the breakdown of the joint. Based on the finite element method, a three-dimensional electromagnetic field simulation model of the cable joint is established in this paper. Simulation results show that the voltage at the head of the cable joint reaches about twice the impulse voltage. The increase of the conductivity of semi-conductive material also leads to the increase of electric field intensity. Then, several points and curves at different positions are selected for further analysis in this paper. Among them, the electric field distortion at the edge of the high voltage shield is the most serious and the electric field in the air gap is the least.
文摘针对变流器不同位置杂散电感准确获取困难的问题,提出一种基于LC高频振荡原理的杂散电感多参数提取方法,充分利用变流器自身结构,通过3个现场实验主动构建不同的谐振电路,并根据它们的振荡频率计算变流器不同位置的杂散电感。首先阐述了高频振荡法的基本原理,建立了不同谐振实验的等值电路模型。然后,以1700 V/450 A IGBT变流器系统为例,通过仿真与实验进行了可行性与有效性验证。最后,通过实验与传统双脉冲法进行了对比分析。研究表明:所提出的方法可有效提取变流器内不同位置的杂散电感参数,与双脉冲法提取开关杂散电感结果基本一致,精度可达纳亨级。
文摘切换试验是考核有载分接开关(on-load tap changer,OLTC)长期运行可靠性的重要试验项目之一。为解决现有切换试验回路试验周期长、试验成本高等问题,该文开展OLTC高效切换试验技术研究。首先,提出一种满足多台OLTC切换的切换试验回路,分析回路参数对试验结果的影响;其次,基于ATP-EMTP进行不同OLTC数量和不同试验方案的仿真分析,提出高效切换试验的试验方案。最后,采用2台不同类型OLTC,按照“一前一后”切换的试验方案,对切换试验回路进行验证。结果表明,该试验回路在多台OLTC进行切换试验时也能满足试验条件,达到了OLTC高效切换试验的需求,可为OLTC高效切换试验提供有益参考。
