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5. Enantiomeric Discrimination by Anisotropic Polarization of Two-Dimensional ReSe2 with Chiral Au Nanoparticles.

Author

Bi, Jinming, Tang, Daiguo, Huang, Ziheng, Wei, Songrui, Wang, Huide, Yang, Xia, Pu, Yong, Dou, Zhifeng, Liu, Zhongxin, and Wang, Jieqiong

Abstract

Enantiomeric discrimination plays a crucial role in the fields of analytical science and chemical biology. Herein, we achieve chiral recognition via angle-resolved polarized Raman scattering using a composite material consisting of an anisotropic two-dimensional material, ReSe2, and chiral Au nanoparticles (CAuNPs). A near-field effect is induced through the attachment of CAuNPs to ReSe2, in conjunction with modulation of polarized light, resulting in simultaneous angular polarization of ReSe2. This angular polarization was utilized for the chiral detection of tyrosine. Varying enantiomeric excess (ee) leads to inverse nonreciprocal angular deflections, which we propose arise from interactions between the chiral near-field and optical vectors modified by chiral molecules with distinct ee values. This phenomenon is primarily attributed to the optical spin Hall effect within the field, generating distinct vector deflections that can be utilized to discriminate between different enantiomers. Ultimately, we demonstrate selective identification of chiral substances by establishing a correlation between the optical inversion angle and ee value. This investigation presents an efficient and insightful approach for achieving rapid detection of chiral substances using rational optical devices. [ABSTRACT FROM AUTHOR]

Published
2024
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6. Comparative analysis of control strategies impact on power losses in IGBT power modules with a multiphysics‐circuit coupling method.

Author

Dou, Zhifeng, Zhang, Changai, Tian, Ye, Lu, Falong, and Wang, Qian

Subjects
*INSULATED gate bipolar transistors, *POWER semiconductors, *PULSE width modulation, *POWER electronics, *VECTOR spaces
Abstract

Power losses in semiconductor devices present a significant impediment to advancing power electronics systems for achieving higher frequencies, improved efficiency, and greater integration. A major challenge lies in directly coupling power losses with various control strategies, considering the variations in manufacturers, packaging, and process structures within the power electronics field. This paper introduces a field‐circuit coupling simulation methodology of the insulated gate bipolar transistor (IGBT) within the Simulink/COMSOL environment, using a conventional three‐phase six‐switch voltage source inverter (VSI) IGBT module as a case study. A composite transfer function interconnects the electrical and thermal aspects, enabling bidirectional coupling between IGBT temperature and losses. This study aims to comprehensively compare the effects of various control strategies, namely, single‐vector, dual‐vector, and three‐vector current model predictive control (CMPC) and space vector pulse width modulation (SVPWM), on the losses and temperature of IGBT power modules. The findings emphasize that losses are significantly influenced by the selection of weighting factor coefficients and power factor settings under the same CMPC control strategy with a fixed switching frequency. Additionally, the selection of control strategies, such as CMPC and SVPWM, substantially impacts power losses in power electronic devices. [ABSTRACT FROM AUTHOR]

Published
2024
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7. A model predictive fault‐tolerant control strategy for non‐redundant T‐inverters with multiphysics‐circuit coupling loss analysis.

Author

Dou, Zhifeng, Tian, Ye, Zhang, Changai, Gao, Haorui, and Lu, Falong

Subjects
*FAULT-tolerant control systems, *PREDICTION models, *TEMPERATURE distribution, *PHASE oscillations, *LOW temperatures, *ADAPTIVE control systems, *PULSE width modulation transformers, *THYRISTORS
Abstract

Summary: This paper presents a multiobjective optimal power prediction fault‐tolerant control (MO2PPC) approach for mitigating DC link neutral‐point voltage imbalance and current ripple problems in three‐level T‐type inverter (3LT2I). Additionally, an auxiliary thyristor is employed to isolate and reconstruct the faulty phase into an 8ST2I for ensuring uninterrupted operation during phase failure. A method called injected bias current‐MO2PPC (IBC‐MO2PPC) fault‐tolerant strategy is proposed for this structure. This approach eliminates the need for DC or AC current sensors to reconstruct the three‐phase current, thereby reducing neutral‐point oscillation caused by phase deficiency and ensuring full power output after failure. Additionally, nonfaulty phase power loss is compared and analyzed to verify the stability of this method following a phase fault. The internal losses and temperature distribution of an IGBT module in a bridge arm before and after a fault are verified through a multiphysics‐circuit model in COMSOL‐Simulink coupling simulation presented last. The model shows reduced conduction losses and overall lower temperature distribution in the IGBT module after fault reconstruction. Experiments and multiphysics simulations have demonstrated that this approach displays exceptional robustness and sustainability throughout the entire fault cycle. [ABSTRACT FROM AUTHOR]

Published
2024
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16. Sliding mode observer‐based AC voltage sensorless model predictive control for grid‐connected inverters

Author

Nan Jin, Yanyan Li, Wu Jie, Leilei Guo, and Dou Zhifeng

Subjects
Observer (quantum physics), Computer science, 020209 energy, Low-pass filter, 020208 electrical & electronic engineering, 02 engineering and technology, Frequency deviation, Grid, Model predictive control, Control theory, Frequency grid, 0202 electrical engineering, electronic engineering, information engineering, Inverter, Electrical and Electronic Engineering, Voltage
Abstract

Recently, model predictive control has been widely used to control grid-connected inverters due to its advantages. However, the conventional model predictive control methods usually require two AC voltage and current sensors to sample the grid voltages and currents. Particularly, the DC voltage sensor is also required to calculate the values of the voltage vectors. The inverter will lose its stability once these sensors fail. Thus, in this study, to improve the operational reliability of the grid-connected inverters, a sliding mode observer-based AC voltage sensorless model predictive control is proposed. First, a sliding mode observer is designed to estimate the grid voltage. Next, a new adaptive compensation strategy is proposed to remove the phase and amplitude errors caused by the low-pass filter. The main novelty of this compensation strategy is that it is immune to the actual grid frequency. Therefore, the grid voltage can be identified accurately, even under frequency deviation conditions. Besides, the stability and parameter designing method of the sliding mode observer is also analysed to provide a theoretical basis for its implementation. Finally, based on the observed grid voltage, the AC voltage sensorless model predictive control is achieved. Detailed comparative experimental results show the validity of the proposed method.

Published
2020

17. Uniform Near-Spherical Nanoscale Silver Films for Surface-Enhanced Raman Spectroscopy Sensing

Author

Yong Chen, Wenhui Yu, Dou Zhifeng, Zhao Zhendong, Mingnan Zhang, and Yanli Xie

Subjects
In situ, Materials science, Chemical engineering, Substrate (chemistry), General Materials Science, Surface-enhanced Raman spectroscopy, Nanoscopic scale
Abstract

Uniform near-spherical nanoscale silver films (NSFs) as a very sensitive and stable SERS-active substrate were synthesized by a facile and efficient in situ liquid–solid–solid (LSS) reaction method...

Published
2020

22. Hybrid voltage vector preselection based model predictive control to reduce the common‐mode voltage for 2‐level voltage source inverters

Author

Lingzhi Cao, Dou Zhifeng, Nan Jin, and Leilei Guo

Subjects
Total harmonic distortion, Computer science, 020209 energy, 020208 electrical & electronic engineering, 02 engineering and technology, Dead time, Model predictive control, Control theory, 0202 electrical engineering, electronic engineering, information engineering, Harmonic, Common-mode signal, Voltage source, Electrical and Electronic Engineering, Voltage reference, Voltage
Abstract

Model predictive control (MPC) strategies have been frequently studied in recent years. To reduce the common-mode voltage (CMV) as well as the current total harmonic distortions (THDs) of the 2-level voltage sources (2L-VSIs), a new MPC strategy is proposed in this study considering both the dead-time and the one-step delay effects. First, the reference voltage vector (VV) prediction based MPC strategy is utilised as it is simple and accurate. Next, the VV preselection strategy is studied in detail to remove the CMV spikes. The effects of the dead time on the CMV are analysed, and an improved VV preselection strategy is presented to reduce the CMV spikes. Then, the one-step delay effects are also analysed, and further improvements are made to completely remove the CMV spikes. Moreover, the maximum variation of the current during one control period is studied in-depth to provide a solid theory foundation for dividing the current sector more accurately. As the six non-zero VVs of the 2L-VSI are fully used in the proposed method, not only the CMV but also the current THDs are reduced. Finally, comparative simulation and experimental studies are carried out to validate the effectiveness of the proposed method.

Published
2019

23. Extraordinary photoexcitation of semimetal 1T'-MoTe2inducing ultrafast charge transfer in lateral 2D homojunction

Author

Chen, Yaohui, Wan, Lingyu, Guo, Di, Lou, Ying, Dou, Zhifeng, Chen, Li, Zhang, Xiuyun, Niu, Xianghong, and Zhai, Junyi

Abstract

Exploring novel and more efficient photoexcitation transition mechanisms in two-dimensional transition metal dichalcogenides (TMDCs) is crucial for the advancement of high-performance optoelectronic devices. In this study, an extraordinary photoluminescence (PL) phenomenon is discovered that originates from a vertical transition between specific bands in the X-point energy valley of K-space in multilayer Weyl semi-metal monoclinic (1T') MoTe2without a gap structure. This effective transition is independent of the bandgap and is unaffected by the number of layers in 1T'-MoTe2, breaking the limitations of traditional TMDCs semiconductor materials and promoting the development of advanced two-dimensional (2D) semimetal-based optoelectronic devices. In a lateral multilayer 1T'-MoTe2-2H hetero-phase homojunction, a record ultrafast transfer of photogenerated charges up to 25 fs is achieved. The highly efficient interband transition, small conduction band energy level difference (less than 100 meV), and exceptionally strong e-p coupling synergistically promote the ultrafast transfer of photo-generated charges. Together with the merits of multilayer 1T'-MoTe2such as higher carrier densities and lower resistance, these findings open the door to potentially ultra-high performance optoelectronic applications.

Published
2024
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24. Dual-Frequency Programmed Harmonics Modulation-Based Simultaneous Wireless Information and Power Transfer System via a Common Resonance Link

Author

Wu, Jie, Zhang, Hengyi, Gao, Pengfei, Dou, Zhifeng, Jin, Nan, and Snášel, Václav

Subjects
Environmental sciences, Environmental effects of industries and plants, simultaneous wireless information and power transfer, wave trapper, selected harmonic elimination PWM, TJ807-830, GE1-350, TD194-195, common resonance link, Renewable energy sources, dual-frequency programmed harmonics modulation
Abstract

Most simultaneous wireless information and power transmission (SWIPT) systems currently operate at a single frequency, where the power and information transmission affect the resonance state of each other. This paper proposes a structure using dual-frequency programmed harmonics modulation (DFPHM). The primary-side inverter outputs a dual-frequency (DF) wave containing the power transmission and information transmission frequencies, while the DF wave is coupled to the secondary side through a common inductive link. After the power and information are transmitted to the secondary side, they are demodulated in different branches. Wave trappers are designed on each branch to reduce the interference of information transmission on power transmission. There is no tight coupling transformer in the system to inject information, so the system order is not high. Experiments verified that the proposed structure based on DFPHM is effective. Web of Science 12 10 art. no. 4189

Published
2020

25. Finite‐state model predictive power control of three‐phase bidirectional AC/DC converter under unbalanced grid faults with current harmonic reduction and power compensation

Author

Chun Gan, Dou Zhifeng, Leilei Guo, Shiyang Hu, and Nan Jin

Subjects
Physics, 020209 energy, 020208 electrical & electronic engineering, 02 engineering and technology, AC power, Grid, AC/AC converter, Phase-locked loop, Model predictive control, Three-phase, Control theory, 0202 electrical engineering, electronic engineering, information engineering, Electrical and Electronic Engineering, Power control, Voltage
Abstract

Under unbalanced grid fault conditions, the current harmonic contents of a three-phase bidirectional AC/DC converter increase significantly and twice grid-frequency ripples exist in both active power and reactive power, which influence the output power quality of the converter. Compared with the conventional finite-state model predictive direct power control (MPDPC), the MPDPC with power compensation (MPDPC-PC) method is proposed for the three-phase bidirectional AC/DC power converter to reduce harmonic currents and output power ripples without extraction of complex positive/negative sequences from the grid voltage/current and phase-locked loop. The power compensation values are expressed by grid voltages and their quadrature signals that lag 90 electrical degrees in the αβ stationary coordinates system. MPDPC-PC exhibits better performance by reducing the harmonic contents of grid currents and eliminating active power or reactive power ripples of the three-phase bidirectional AC/DC converter with flexible reactive power compensation capability. Compared with the MPDPC and linear current control schemes, experimental results confirm the effectiveness of the designed method under unbalanced grid conditions.

Published
2018

34. Current predictive control method of three-level ANPC grid-connected inverter based on optimized cost function.

Author

WANG Nan, DOU Zhifeng, LI Yanyan, and WU Jie

Subjects
*COST functions, *PREDICTION models, *MATHEMATICAL models, *VOLTAGE
Abstract

Aiming at the problems of complicated calculation process, large neutral pointe potential fluctuation and large output current harmonic of the traditional three-level ANPC grid-connected inverter limited control set model predictive control, a current control method of three-level ANPC grid-connected inverter based on optimized cost function was proposed. This method simplified the steps of establishing the intermediate variable of the DC side mid-point voltage offset ΔUdc and the three-phase switching state Sx in the traditional model predictive control method. Under the static αβ coordinate system, the relationship between load current i, ΔUdc and Sx was used to directly establish a mathematical model. Through the real-time calculation of 27 switch states, the optimal output switch state was selected. Simulation and experiment result showed that the method effectively reduced the total harmonic distortion rate and achieved the effect of suppressing midpoint voltage fluctuations. [ABSTRACT FROM AUTHOR]

Published
2021
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35. Analysis of efficiency characteristics of compensation topology structure in magnetic coupled resonance wireless power transfer.

Author

WU Zhenjun, FENG Kai, DOU Zhifeng, GAO Pengfei, JIN Nan, and WU Jie

Subjects
WIRELESS power transmission, TOPOLOGY, MAGNETIC resonance, MAGNETIC structure, QUALITY factor, MAGNETIC fields, MAGNETIC coupling
Abstract

Four resonance compensation topologies equivalent circuit models for magnetic field coupling resonance wireless power transfer system (primary side series and secondary side series type, primary side series secondary side parallel type, primary side parallel secondary side series type and primary side parallel secondary side parallel type) was constructed. The efficiency characteristics of magnetic field coupling resonance wireless power transfer system was analyzed. The influence of coupling coefficient and quality factor on system efficiency was studied. The simulation results showed that the secondary side resonance compensation topology had a greater impact on the system efficiency, and the system efficiency was more sensitive to changes in the coupling coefficient and quality factors. Compared with the secondary side using the series compensation topology, the system had a wider range of high transfer efficiency when the secondary side used the parallel compensation topology. The experimental results verified the correctness of the simulation results. [ABSTRACT FROM AUTHOR]

Published
2021
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40. Optimization of constant power transmission efficiency for wireless power transfer system with SiC dual full bridges.

Author

DOU Zhifeng, ZHAO Chongyan, HE Shuaibiao, and JIN Nan

Subjects
*WIRELESS power transmission, *POWER transmission
Abstract

Aiming at the problem of transmission efficiency change in the wireless power transfer system constant power transmission under different loads, by establishing the SiC dual full bridge wireless power transfer system model, the corresponding relationships between the primary side voltage angle and the transmission power, the secondary side voltage angle and the transmission efficiency were deduced, and the optimization of the constant power transmission efficiency was studied. The results showed that under the condition of variable load, the equivalent load was optimized by adjusting the secondary side voltage angle to maximize the transmission efficiency. The experimental comparison between the dual full bridge structure and the uncontrolled rectifier structure proved that the dual full bridge structure could significantly improve the transmission efficiency. The efficiency was increased by 19% when the transmission power was 100 W at the load of 30 Ω. [ABSTRACT FROM AUTHOR]

Published
2019
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44. Design and evaluation of a PCB dual−switch fuse with energetic materials embedded. Application for new fail−safe and fault−tolerant converters

Author

Dou, Zhifeng, Sarraute, Emmanuel, Richardeau, Frédéric, Bley, Vincent, Blaquière, Jean Marc, Vella, C., Gonthier, G., Pistre, Karine, LAboratoire PLasma et Conversion d'Energie (LAPLACE), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Convertisseurs Statiques (LAPLACE-CS), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Matériaux Diélectriques dans la Conversion d’Energie (LAPLACE-MDCE), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), and Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SPI]Engineering Sciences [physics], [SPI] Engineering Sciences [physics]
Abstract

International audience; n this paper, a new concept of passive dual-switch fuse is proposed, allowing to symmetrically disconnecting a switching cell against a leg short circuit failure. This device is composed of a di-phase fuse connected in series with a switching cell. It is made of standard printed circuit board, including in its thickness, an energetic material in order to assist the disconnection, combining a dual-fuse mode and a passive dual-switch mode. Firstly, we present the mechanical design of the dual-switch and the first tests of rupture by means of an energetic material buried. In a second step, we describe the design of the dual-fuse on PCB and electrothermal finite elements simulations by means of Comsol 3D TM. Finally, a combined dual-switch fuse prototype is fully integrated in a voltage source inverter and experimentally validated.

Published
2013

45. Conception et évaluation d’un rupteur-fusible multivoies, à assistance pyrotechnique, intégré sur PCB, pour l’isolement des défauts internes des convertisseurs d’électronique de puissance. Application à une nouvelle structure de redondance

Author

Dou, Zhifeng, Sarraute, Emmanuel, Richardeau, Frédéric, Bley, Vincent, Blaquière, Jean Marc, Vella, C., Gonthier, G., Pagès, Nathalie, LAboratoire PLasma et Conversion d'Energie (LAPLACE), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Convertisseurs Statiques (LAPLACE-CS), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Centre National de la Recherche Scientifique (CNRS), Matériaux Diélectriques dans la Conversion d’Energie (LAPLACE-MDCE), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), and Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SPI.NRJ]Engineering Sciences [physics]/Electric power, [SPI.NRJ] Engineering Sciences [physics]/Electric power
Abstract

National audience

Published
2012

46. PCB dual-switch fuse with energetic materials embedded. Application for new fail-safe and fault-tolerant converters

Author

Dou, Zhifeng, Richardeau, Frédéric, Sarraute, Emmanuel, Bley, Vincent, Blaquière, Jean Marc, Vella, C., Gonthier, G., Pagès, Nathalie, LAboratoire PLasma et Conversion d'Energie (LAPLACE), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Convertisseurs Statiques (LAPLACE-CS), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Centre National de la Recherche Scientifique (CNRS), Matériaux Diélectriques dans la Conversion d’Energie (LAPLACE-MDCE), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), and Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SPI.NRJ]Engineering Sciences [physics]/Electric power, [SPI.NRJ] Engineering Sciences [physics]/Electric power
Abstract

International audience

Published
2012

47. New design and evaluation of a fully integrated PCB dual-switch fuse – Energetic materials assisted. Application for new fail-safe and fault-tolerant converters

Author

Dou, Zhifeng, Richardeau, Frédéric, Sarraute, Emmanuel, Bley, Vincent, Blaquière, Jean Marc, Vella, C., Gonthier, G., LAboratoire PLasma et Conversion d'Energie (LAPLACE), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Convertisseurs Statiques (LAPLACE-CS), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Centre National de la Recherche Scientifique (CNRS), Matériaux Diélectriques dans la Conversion d’Energie (LAPLACE-MDCE), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Pagès, Nathalie

Subjects
[SPI.NRJ]Engineering Sciences [physics]/Electric power, [SPI.NRJ] Engineering Sciences [physics]/Electric power
Abstract

International audience

Published
2012

48. Sûreté de fonctionnement des convertisseurs - Nouvelles structures de redondances pour onduleurs sécurisés à tolérance de pannes

Author

Dou, Zhifeng, Institut National Polytechnique de Toulouse - INPT (FRANCE), and Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)

Subjects
Mode défaillant, Rupteur-fusible, Onduleur à tolérance de pannes, Matériaux énergétiques
Abstract

Au sein d'un convertisseur la défaillance d'un composant de puissance est un événement critique tant par le risque d'explosion du boitier et sa propagation au sein du système (forte énergie stockée dans l'alimentation) que par l'interruption de service qui en découle (systèmes embarqués, systèmes de production en flux tendu). Ce mémoire de thèse propose un ensemble de solutions nouvelles portant sur la problématique de l'isolement ultime de défauts "derniers secours" d'une part, et sur la connexion "automatique" et à faible "coût" d'un circuit en secours. L'objectif de cette approche globale est de concilier "sécurité électrique absolue" et "continuité de service" pour les systèmes de conversion sensibles devant être intégrés au coeur des applications critiques. Le premier chapitre et son annexe permettent de rappeler les causes et les conséquences des défauts internes au sein d'une structure de base d'onduleur à deux niveaux de tension, laquelle fait l'objet de nombreuses simulations de modes dégradés en configuration variateur de vitesse sur machine synchrone. De cette analyse il ressort qu'une structure d'isolement symétrique à deux voies couplées, placées sur les pôles du bus DC, à déclenchement spontané (fusible) et/ou commande (rupteur), est à même de sécuriser toutes les mailles du circuit, de façon modulaire et non intrusive. En exploitant la propriété du premier mode de défaillance d'une puce de puissance dans un état très faiblement ohmique, nous proposons une nouvelle structure de couplage à aiguillage à diodes permettant, à l'inverse des solutions actuelles, de réaliser un lien de connexion automatique "en série" et à travers la conduction même des composants défaillants. Nous montrons ainsi qu'une seule redondance passive parallèle peut être mutualisée et secourir indifféremment un nombre quelconque de phases. Ce concept est ensuite décliné en plusieurs variantes, avec auxiliaire de déclenchement, en version hacheur et onduleur à trois niveaux de tension. Le deuxième chapitre propose une démarche de conception et de test d'une série de prototypes de rupteurs – fusibles, réalisés et complètement intégrés par le biais des technologies de type PCB (Printed Circuit Board) et l'apport d'un matériau énergétique. Les conceptions mécanique, électrique et pyrotechnique sont présentées assorties de résultats de test intermédiaires. De cet ensemble de travaux il ressort que la technologie PCB1 prépreg combinée à l'insertion d'un matériau énergétique enfouis au sein d'une chambre de combustion et initié par des plateformes chauffantes CMS, semble prometteuse de par les résultats intermédiaires obtenus, son faible coût technologique et son fort potentiel d'intégrabilité sur carte de puissance. Le troisième chapitre présente des caractérisations de résistance apparente de puces défaillantes en régime de court-circuit, de manière comparée entre les technologies d’encapsulants époxy et gel silicone et dans des conditions de court-circuit de faible énergie, de faible I2Tp, par l'insertion de "dual-fuses" rapides conformément au concept propose. Des nombreux résultats expérimentaux nous retenons d'une part, les bénéfices d'un encapsulant massif et rigide permettant de durcir l'attache des pieds de bonding et ainsi de bénéficier d'une faible valeur de résistance de court-circuit stable dans le temps et d'autre part, la propriété de redondance parallèle des fils de bonding réalisée par le plan de métal et les pads équipotentiels. Des perspectives technologiques prometteuses sont également proposées au niveau de la structure et de la technologie des interconnexions visant à fonctionnaliser cette région à des fins de sécurité électrique. Le quatrième et dernier chapitre présente la mise en oeuvre des concepts, des dispositifs d'isolement et de connexion secours sur une maquette d'onduleur de tension DC 350V / AC 50A mettant en jeu différentes technologies d'isolement ("dual-fuses" miniaturises, CMS, PCB passive réalisé au laboratoire) et l'évaluation du dispositif de couplage – aiguillage à diodes d'un bras en redondance parallèle. Un détecteur local et rapide de défaut couple à un superviseur numérique permet d'ordonnancer les étapes d'isolement et de commutation du mode "normal – secours" en quelques dizaines de microsecondes. Les résultats obtenus, même sur un cas d'étude particulier, sont globalement très positifs et nous retiendrons entre autres la nécessité de développer une technologie de fusibles à forte dynamique d'isolement (régime de recouvrement rapide d'impédance postarc) permettant un mode de reprise à minimum de temps mort.

Published
2011

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