Hao Zou, Fang Xie, Bo Du and G. Kavithaa
The purpose of this paper is to find the optimum inverter type as the solder joint reliability point of view.
Abstract
Purpose
The purpose of this paper is to find the optimum inverter type as the solder joint reliability point of view.
Design/methodology/approach
In this paper, finite element model(ing) simulations supported with power cycling aging experiments were used to demonstrate the best inverter type as the solder joint reliability point of view.
Findings
It was found that inverter types highly affect the solder joint health during its nominal operating.
Originality/value
The authors confirm the originality of this paper.
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Buen Zhang, Noor H. Jabarullah, Ayad F. Alkaim, Svetlana Danshina, Irina V. Krasnopevtseva, Yuan Zheng and Nisith Geetha
This paper aims to establish a more accurate model for lifetime estimation.
Abstract
Purpose
This paper aims to establish a more accurate model for lifetime estimation.
Design/methodology/approach
Finite element model simulation and experimental tests are used to enhance the lifetime prediction model of the solder joint.
Findings
A more precise model was found.
Originality/value
It is confirmed that the paper is original.
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Wenhui Cai, Fei Huang, Kai Liu and Mohammed Alaazim
As in real applications several alternating current (AC) currents may be injected to the electronic devices, this study aims to analyze their effects on the lifetime of the solder…
Abstract
Purpose
As in real applications several alternating current (AC) currents may be injected to the electronic devices, this study aims to analyze their effects on the lifetime of the solder joints and, consequently, shed the light on these effects at the design phase for other researchers to consider.
Design/methodology/approach
In this paper, the authors investigated on current waveform shapes on the performance and reliability of the solder joints in electronic package. Three common and extensively used current shapes in several simulations and experiments were selected to study their effects on the solder joint performance.
Findings
The results demonstrate a sever thermal swing and stress fluctuation in the solder joint induced in the case of triangle current type because the critical states lack any relaxation time. In fact, the stress intensification in the solder under application of the triangle current type has been shown to contribute to increasing brittle intermetallic compounds. An accelerated increase of on-state voltage of power semiconductor was also observed in under application of the triangle current type.
Originality/value
The originality of this paper is confirmed.
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Sathish Kumar, Oleg R. Kuzichkin, Ahmed Faisal Siddiqi, Inna Pustokhina and Aleksandr Yu Krasnopevtsev
This study aims to investigate simultaneous power and thermal loading.
Abstract
Purpose
This study aims to investigate simultaneous power and thermal loading.
Design/methodology/approach
Finite element method simulations coupled with experiments.
Findings
The effects of power cycling have been determined.
Originality/value
This paper aims to testify the combined effects of thermal and power cycling loads on the reliability of solder ball joints with barrel- and hourglass-type geometries in an electronic system. The finite element simulation outcomes showed that the maximum strain energy was accumulated at the edges of barrel-type solder, whereas the hourglass-type was vulnerable at the necking side. It was also found that the hourglass-type solder showed a reliable behavior when the sole thermal cycling was exerted to the electronic system, whereas the barrel-type solder was a better choice under simultaneous application of thermal and power loadings. The experimental results also confirmed the finite element simulation and indicated that the solder joint reliability strongly depends on the geometry of interconnection in different operating conditions. An extensive discussion was presented to shed light on the paramount importance of combined thermal/power cycling on the reliability of solder joints.
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Yumin He, Tingyun Gu, Bowen Li, Yu Wang, Dongyuan Qiu, Yang Zhang and Peicheng Qiu
Electric spring (ES) is a demand response method that can stabilize the voltage of critical loads and improve power quality, especially in a weak power grid with a high proportion…
Abstract
Purpose
Electric spring (ES) is a demand response method that can stabilize the voltage of critical loads and improve power quality, especially in a weak power grid with a high proportion of renewable energy sources. Most of existing ESs are implemented by voltage-source inverter (VSI), which has some shortcomings. For example, the DC-link capacitor limits the service life of ES, and the battery is costly and hard to recycle. Besides, conventional VSI cannot boost the voltage, which limits the application of ES in high-voltage occasions. This study aims to propose a novel scheme of ES to solve the above problems.
Design/methodology/approach
In this work, an ES topology based on current-source inverter (CSI) without a battery is presented, and a direct current control strategy is proposed. The operating principles, voltage regulation range and parameter design of the proposed ES are discussed in detail.
Findings
The proposed ES is applicable to various voltage levels, and the harmonics are effectively suppressed, which have been validated via the experimental results in both ideal and distorted grid conditions.
Originality/value
An ES topology based on battery-less CSI is proposed for the first time, which reduces the cost and prolongs the service time of ES. A novel control strategy is proposed to realize the functions of voltage regulation and harmonic suppression.
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Sh. Fadaie, M.M. Kashani‐Motlagh, A. Maghsoudipour and B. Faridnia
The purpose of this paper is to evaluate the effect of copolymer and starting material concentrations in homogeneous precipitation synthesis of Yttria nanoparticles and…
Abstract
Purpose
The purpose of this paper is to evaluate the effect of copolymer and starting material concentrations in homogeneous precipitation synthesis of Yttria nanoparticles and red‐emitting nanophosphors Y2O3:Eu3+. N‐isopropylacrylamide and acrylic acid (NIPAM/AAc) and urea are used.
Design/methodology/approach
To optimise synthesis condition of Y2O3:Eu3+ nanophosphor NIPAM/AAc copolymer was used as a modifier and the effect of various concentration of yttrium ions, urea and precipitation time on size, morphology and emission spectra were investigated.
Findings
Using NIPAM/AAc copolymer shows significant improvement on size and dispersion of nanoparticles. It is found that yttrium concentration, varying between 0.006 and 0.03 M, has a profound impact on the average size of particles, which systematically increases from 65 to over 165 nm. The rate of precipitation reaction, however, is shown to be independent of yttrium concentration. In contrast, as urea concentration increases from 0.2 to 5 M, the average particle size exhibits a gradual decrease from 183 to 70 nm. At extremely high urea concentration such as 5 M, a significant level of inter‐particle agglomeration is observed.
Originality/value
Based on this paper, the authors have successfully prepared some promising nanophosphors. The nanoparticles are studied by X‐ray diffraction, transmission electronic microscopy, zeta sizer, Infra red and photoluminescence spectroscopy.