A Novel Approach to Accurately Determine the tq Parameter of Thyristors

International audienceThe continued use of high-voltage thyristor devices in industry and their increased use in high-voltage dc transmission systems call for more attention to the properties of these devices. One of the important thyristor parameters is their turn-off time tq, which can be a limiting factor when applying thyristors at elevated switching frequencies. Hence, the accurate measurement of tq and its variation versus the operating conditions remains a crucial task for thyristor converters operating at elevated switching frequencies. In this paper, a proper test circuit for measuring this parameter with a high level of accuracy has been designed and built. Owing to the test circuit specificity, the variation effects of several electrical and physical constraints, such as the forward current IF , the reverse applied voltage VR, the operating temperature To, and the ramp rate of the forward reapplied voltage dVD/dt, on the tq parameter of thyristors are also studied and analyzed based on the physics of semiconductor devices and associated simulations

Contribution à la modélisation électro-thermique de la cellule de commutation MOSFET-

La simulation des convertisseurs de puissance et les composants de puissance est un chalenge important des prochaines années. En effet, la réalisation de prototype est de plus en plus longue et coûteuse. Aussi le prototypage virtuel, c\u27est-à-dire la simulation précise des convertisseurs est-elle fondamentale. Ce travail a analysé les possibilités de la simulation par éléments finis d\u27une cellule de commutation MOS - Diode. En particulier la modélisation électrothermique de la diode a été réalisée. De plus, une procédure originale d\u27extraction des paramètres technologiques a permis d\u27obtenir d\u27excellents résultats de comparaisons simulation/expérience y compris pour les phases de commutations rapides. Pour atteindre cette objectif, une analyse et une modélisation précise de câblage a été entreprise. Enfin, une analyse des couplages électrothermiques a permis de développer un modèle à base de graphes de liens capable de prendre en compte les gradients de température qui existent notamment dans un autoéchauffement

Electro-thermal simulation including a temperature distribution inside power semiconductor devices

International audienceThe idea of including non-uniform temperature distribution into power semiconductor device models is not new, as accurate electro-thermal simulations are required for designing compact power electronic systems (as integrated circuits or multi-chip modules). Electro-thermal simulations of a PIN-diode based on the finite-element method, show a non-uniform temperature distribution inside the device during switching transients. Hence the implicit assumption of a uniform temperature distribution when coupling an analytical electrical model and a thermal model yields inaccurate electro-thermal behaviour of the PIN-diode so far. If literature reports procedures regarding complex thermal network modelling, few papers address the problem of mixing adequately electrical and thermal issues. Instead of using a one-dimensional finite difference or element method, the bond graphs and the hydrodynamic method are used to build a 1D electro-thermal model of the PIN-diode. The paper focuses on electrical issues and the proper expression and localization of power losses to feed the thermal network model. The results by this original technique are compared with those given by a commercial finite-element simulator. The results are similar but the computation effort attached to the proposed technique is a fraction of that required by finite-element simulators. Moreover the proposed technique may be applied easily to other power semiconductor devices

The Role of a Wiring Model in Switching Cell Transients: the PiN Diode Turn-off Case

International audiencePower converter design requires simulation accuracy. In addition to the requirement of accurate models of power semiconductor devices, this paper highlights the role of considering a very good description of the converter circuit layout for an accurate simulation of its electrical behavior. This paper considers a simple experimental circuit including one switching cell where a MOSFET transistor controls the diode under test. The turn-off transients of the diode are captured, over which the circuit wiring has a major influence. This paper investigates the necessity for accurate modeling of the experimental test circuit wiring and the MOSFET transistor. It shows that a simple wiring inductance as the circuit wiring representation is insufficient. An adequate model and identification of the model parameters are then discussed. Results are validated through experimental and simulation results

Losses evaluation in converters using the calorimetric technique

International audienceIn this paper, a measurement technique of losses in the switching cell, based on calorimetric technique is presented. A special calorimeter was designed to be able to access the heat generated by an operating converter. Power component losses are studied according to the cyclic ratio and to operating frequency and an extraction method of the different terms of these losses, using calorimetric measurements, is presented. An accurate expression of the switching losses in the power semiconductors devices is proposed

A novel approach to extract accurate design parameters of PiN diode

Article en ligne sur : Wiley InterScience (www.interscience.wiley.com).International audienceAccurate modelling of PiN diode transient behaviour is necessary to extract design parameters which are not documented in datasheets. To meet this requirement, this paper introduces a novel approach giving the possibility to identify accurate parameters of a given device. The used technique is based only on two stages. First, the design parameters are initialized and optimized. Second, they are refined by minimizing the cost function which depends on the transient switching parameters (IRM, VRM and trr). With a simple and CPU time-saving approach this technique leads to extract design parameters without necessarily knowing the exact technological architecture of the PiN diode. Moreover, in order to validate the proposed approach and the parameter extraction procedure three commercial diodes are tested. A good agreement between experimental and simulation data is obtained

On the role of the N-N+ junction doping profile of a PIN diode on its turn-off transient behavior

Nos remerciements à IEEE pour l'autorisation de mise à disposition du papier complet. © IEEE Copyright Notice : Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.International audienceThis paper focuses on the role of the N-N+ junction doping profile model of a PiN diode on its turn-off transient and, particularly, the influence of multiple epitaxies in the N-N+ profile. A conventional doping profile model has been used in a previous work and an identification procedure for the main design parameters has been demonstrated. However the validity range of identified PiN-diode models appeared quite limited for hard current and voltage conditions. Readers have asked for the effect of a more advanced doping profile. The turn-off transient of an STTB506D device is considered from experimental and simulation point-of-view inside a fully characterized switching cell. A limitation of the conventional doping profile model is demonstrated and explained physically in order to introduce the necessity of a more complex doping profile. An advanced doping profile is then considered and a comparative study between experimental and simulated turn-off transient behavior of the device is established

On the extraction of PiN diode design parameters for validation of integrated power converter design

International audienceDesign of integrated power systems requires prototype-less approaches. Accurate simulations are necessary for analysis and verification purposes. Simulation relies on component models and associated parameters. The paper focuses on a step-by-step extraction procedure for the design parameters of a one-dimensional finite-element-method (FEM) model of the PiN diode. The design parameters are also available for diverse physics-based analytical models. The PiN diode remains a complex device to model particularly during switching transients. The paper demonstrates that a simple FEM model may be considered unknowingly of the device exact technology. Heterogeneous simulation is illustrated. The state-of-art of parameter extraction methods is briefly recalled. The proposed procedure is detailed. The diode model and extracted parameters are systematically validated from electro-thermal point-of-view. Validity domains are discussed

A novel design approach for the epitaxial layer for 4H-SiC and 6H-SiC power bipolar devices

International audienceThe paper evaluates the optimal design of the low-doped base region inside power diodes and other bipolar devices. It is demonstrated theoretically that a low-doped base region of P+N-N+ diodes can provide a high breakdown voltage and an optimal on-resistance R-on. A simple, accurate and CPU timesaving approach is presented to extract an optimal value for the base region width, W-B. and its doping concentration, N-D. The paper details an analytical relation between W-B and N-D, and gives a method for quantifying the trade-off between their values for a given breakdown voltage and for obtaining the minimal on-resistance. Analytical results are confronted with experimental results for 4H-SiC- and 6H-SiC-based diodes