Search results for "Format"

Effect of process parameters and crystal orientation on 3D anisotropic stress during CZ and FZ growth of silicon

2017

Abstract Simulations of 3D anisotropic stress are carried out in and oriented Si crystals grown by FZ and CZ processes for different diameters, growth rates and process stages. Temperature dependent elastic constants and thermal expansion coefficients are used in the FE simulations. The von Mises stress at the triple point line is ~5–11% higher in crystals compared to crystals. The process parameters have a larger effect on the von Mises stress than the crystal orientation. Generally, the crystal has a higher azimuthal variation of stress along the triple point line (~8%) than the crystal (~2%). The presence of a crystal ridge increases the stress beside the ridge and decreases it on the ri…

Temperature Dependent Suns-V<inf>oc</inf> of Multicrystalline Silicon Solar Cells from Different Ingot Positions

2018

This paper presents temperature dependent Suns- Voc measurements on multicrystalline silicon cells originating from different ingot positions. The effective lifetime is found to increase for all cells when the temperature is increased from 25°C to 6°C. However, cells from the top of the ingot show a considerably larger increas 40–50% for illumination conditions of 0.1-1 Sun, compared to an increase of 20-30% observed for cells from the bottom. The decrease in Voc with increasing temperature is found to be lower for cells from the top of the ingot compared to cells from the bottom. The temperature coefficient of the Voc is found to vary 5% along the ingot at 1 Sun, highlighting the influence…

SiC MOSFET vs SiC/Si Cascode short circuit robustness benchmark

2019

Abstract Nowadays, MOSFET SiC semiconductors short circuit capability is a key issue. SiC/Si Cascodes are compound semiconductors that, in some aspects, show a similar MOSFET behaviour. No interlayer dielectric insulation suggests, in theory, Cascode JFETs as more robust devices. The purpose of this paper is to compare the drift and degradation of two commercial devices static parameters by exposing them to different levels of repetitive 1.5 μs short-circuit campaigns at 85% of its breakdown voltage. Short-circuit time has been set experimentally, and longer times result in catastrophic failure of MOSFET devices due to over self-heating. For this purpose, pre- and post-test short circuit ch…

3D magnetic and thermal fields for in the transformer with homogenised amorphous C-core under high frequency

2017

Space Charges and Partial Discharges Simultaneous Measurements under DC Stress

2016

In the field of HVDC, the main causes of insulation aging are due to the space charge and PD phenomena. In particular, the purpose of the present work is to verify a possibility to measure simultaneously the space charge and the PDs under DC stress in order to evaluate the correlation between both phenomena. The space charge was measured by using a modified PEA cell and PDs were measured by using a novel wireless sensor system. The space charge profile and the PD pulses carried out simultaneously have been reported and discussed.

Partial discharge of gel insulated high voltage power modules subjected to unconventional voltage waveforms

2016

Performances and duration of the new generation of high voltage power electronic components are dependent on dielectric materials aim to insulating their internal terminals. The presence of defects, some due to faults generated during the manufacturing process, but also due to the internal design of layers and connections, can cause local enhancements of electric field and consequently possible activity of partial discharges phenomena or other effects (aging, tracking) that may result in reduction of device reliability. Furthermore, the usage of unconventional voltage waveforms, like square waves or pulse width modulated waves, additionally increases the electrical aging of the insulation s…

Deformation of bubbles in silicon gel insulation under an alternating electric field

2019

The behavior of silicone gel under electrical stress plays a significant role in the reliability and durability of high voltage electronic power devices due to its widespread use for the insulation of IGBT modules and other components. The charges accumulation at the bubble boundaries leads to significant displacements due to the establishment of Coulombic forces and the high deformability of colloidal system. The main purpose of this work is to validate a numerical approach useful to investigate, for a given silicone gel, the non-linear relation between the applied HVDC stress and the electric field over an air bubble within the insulation bulk. The analysis has been carried out by means o…

State-space formulation of scalar Preisach hysteresis model for rapid computation in time domain

2015

A state-space formulation of classical scalar Preisach model (CSPM) of hysteresis is proposed. The introduced state dynamics and memory interface allow to use the state equation, which is rapid in calculation, instead of the original Preisach equation. The main benefit of the proposed modeling approach is the reduced computational effort which requires only a single integration over the instantaneous line segment in the Preisach plane. Numerical evaluations of the computation time and model accuracy are provided in comparison to the CSPM which is taken as a reference model.

Study of the multipactor phenomenon using a full-wave integral equation technique

2017

Abstract Multipactor effect is a well-known phenomenon of RF breakdown in satellite payloads which degrades components, generates undesirable harmonics, contributes to power dissipation and increases noise in communications. Traditionally, multipactor has been investigated with the aim of obtaining the so-called multipactor threshold voltage, or to present different multipaction detection methods. However, very little attention has been focused on analysing this phenomenon using a multimodal approach. The main goal of this work is to analyse the interaction between a multipactor current and a realistic microwave cavity by means of a rigorous and accurate formulation. For the first time to t…

The peculiarities of the radiation damage accumulation kinetics in the case of defect complex formation

2020

Abstract The kinetics of radiation defect accumulation under irradiation by heavy particles is theoretically analysed under the assumption of defect complex genesis, particularly, the ones of anion and cation vacancies. The obtained analytical mathematical model and revealed peculiarities of radiation dose dependencies can be used for analysis of the experimental results for different crystalline materials for solid-state electronics and photonics.