Bibliographies thématiques / Bipolar PWM

Littérature scientifique sur le sujet « Bipolar PWM »

Auteur : Grafiati
Publié le 14 mars 2023

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Articles de revues sur le sujet "Bipolar PWM"

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Fathoni, Fathoni. « RANCANG BANGUN PERANGKAT PEMBANGKIT PWM BIPOLAR ». JURNAL ELTEK 16, no 1 (21 août 2018) : 14. http://dx.doi.org/10.33795/eltek.v16i1.83.

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Electrical power settings, both AC and DC can be done by linear or switching. Controlled loads may be motors, heating elements or incandescent lamps. Generally the efficiency of load power control by way of switching is better than linear way so the way switching is widely used today. Switching also allows for automatic, remote and wireless control In load power management system with microcontroller, PWM generator circuit output is used for control of power switch. The output pulse can be TTL standard or with lower amplitude and on the control of the H bridge circuit required bipolar PWM with additional dead band on each side of the pulse ride. The bipolar PWM generator designed in this study has an output with TTL standard with a dead band circuit and a short circuit protection for VCC = 5 volts and a ground path, Testing with no load and short circuit in low and high output states is as follows. VOL(min) = 0.4 volts, VOH(max) = 4.2 volts. The short circuit of output to high GND is 100 mA and short circuit current to VCC path at low output is 90 mA, The output frequency of bipolar pulses is, 50, 100, 1k, 10k and 20k Hz with 10μs dead band
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Shen, Bin, Peng Kai Ji et Sha Sha Ren. « Combined PWM Motor Control Study and Application in EPS ». Applied Mechanics and Materials 220-223 (novembre 2012) : 473–77. http://dx.doi.org/10.4028/www.scientific.net/amm.220-223.473.

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The power switch circuit of electrical power steering (EPS) is analyzed. A kind of PWM hybrid control algorithm combining the Unipolar reversible PWM mode of brush DC motors with its bipolar reversible PWM mode is put forward in this paper to improve the performance of current EPS system. The basic switch principle between Unipolar and Bipolar PWM mode is that the voltage during the switch process remains constant. The switch process and practical application of DC motor with Uni-Bipolar hybrid control mode in EPS is analyzed. The results show that PWM hybrid mode has exhibited good performance in vehicle electric power steering system.
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Attia, Hussain, Hang Seng Che, Tan Kheng Suan Freddy et Ahmad Elkhateb. « Bipolar and unipolar schemes for confined band variable switching frequency PWM based inverter ». International Journal of Electrical and Computer Engineering (IJECE) 11, no 5 (1 octobre 2021) : 3763. http://dx.doi.org/10.11591/ijece.v11i5.pp3763-3771.

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The single phase inverter performance through the unipolar and bipolar strategies has been previously analyzed based on the constant switching frequency pulse width modulation (CSFPWM). However, the confined band variable switching frequency PWM (CB-VSFPWM) is currently proposed as a new variable switching frequency PWM technique through unipolar strategy to facilitate the design of high order filter, to reduce the switching losses, and to reduce the current total harmonics distortion (THD) as well. To evaluate the performance of a single phase inverter based on the CBVSFPWM through bipolar strategy, this paper presents a comparative study of the CB-VSFPWM based inverter performance using the unipolar PWM and the bipolar PWM strategies. The study adopts MATLAB/Simulink to simulate the inverter and to analyze the simulation results in terms of harmonics spectrum, total harmonic distortion (THD), and fundamental components. The analysis of the study results gives an indication about the appropriate type of CB-VSFPWM strategy (unipolar PWM or bipolar PWM) to guarantee the desired performance of the connected inverter in terms of the electrical grid standards like THD, and harmonics spectrum of the inverter current.
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Zhao, Zhi Chao, Tie Feng Wu, Jing Li, Li Min Li, Qie Pan et Jiang Chang. « A Design of Low Temperature Dependence Voltage Reference Circuit for PWM Controller ». Applied Mechanics and Materials 310 (février 2013) : 448–52. http://dx.doi.org/10.4028/www.scientific.net/amm.310.448.

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In order to provide steady voltage for PWM controller, a design of bipolar voltage reference circuit with high performance is presented. The circuit based on the compensation principle between Zener diode and B-E junction of triode is used in PWM controller and can bring out multi-way steady voltages, moreover, there is a high power supply rejection ratio (PSRR) and low temperature dependence. The results of simulation and test in Candence with bipolar process of HuaYue SB45 show that the temperature coefficient is about 1.2ppm/°C in the temperature range -55~125°C. The line regulation is about 0.4mV/V in 8~30V and the PSRR is 77.54dB. The design of circuit can satisfy the requirements of PWM controller.
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Wang, Xiao Yan, et Jian Ping Liu. « Design of Oscillator for PWM Controller ». Applied Mechanics and Materials 157-158 (février 2012) : 1242–45. http://dx.doi.org/10.4028/www.scientific.net/amm.157-158.1242.

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An oscillator is designed for PWM controller chip. The resistance Rt and capacitance Ct for oscillator are located outside the chip to adjust the frequency expediently. The circuit is simulated by CADENCE Spectre, and the simulation results show that the frequency of the oscillator is 52.84KHz (at Vcc=15V), voltage stability is 0.4%. The layout is done based on the process flow and layout levels of bipolar 45V process provided by HUAYUE Microelectronics Company. The test results prove that the oscillator present in this paper meets the design requirements.
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Prest, R. B., et J. D. Van Wyk. « Reverse bipolar transistor conduction in high-current PWM inverters ». IEEE Transactions on Power Electronics 3, no 3 (juillet 1988) : 246–53. http://dx.doi.org/10.1109/63.17942.

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Song, Min-Sup, In-Ho Cho et Jae-Bum Lee. « ± 180° Discontinuous PWM for Single-Phase PWM Converter of High-Speed Railway Propulsion System ». Energies 13, no 7 (26 mars 2020) : 1550. http://dx.doi.org/10.3390/en13071550.

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As high-capacity alternating current/direct current (ac/dc) power conversion systems, single-phase pulse-width modulation (PWM) converters used in high-speed railway propulsion systems adopt high-voltage Insulated-Gate Bipolar Transistors (IGBTs) as switching elements. Due to their high breakdown voltage characteristics, the switching dynamics are inferior to those of low-voltage IGBTs and switching losses are more dominant than conduction losses despite operating at relatively low switching frequencies of hundreds to several kHz. To solve this problem, this paper proposes ± 180° discontinuous PWM (DPWM) suitable for a single-phase circuit. With the simple addition of offset voltages, the proposed DPWM method can be implemented easily and switching losses can be reduced by half by clamping the switching legs of the H-bridge converter to the positive or negative dc rail during every half cycle. In addition, temperature deviation between the power stacks can be minimized by using selective application of clamping modes. The validity and effectiveness of the proposed DPWM are verified through simulations and experiments of a prototype converter.
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Wang, Pengde, et Xun Lu. « DC Motor Detection and Protection Based On Bipolar PWM Drive ». IOP Conference Series : Earth and Environmental Science 252 (9 juillet 2019) : 032148. http://dx.doi.org/10.1088/1755-1315/252/3/032148.

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Jiang, Maoh Chin, Huang Kai Fu et Kao Yi Lu. « A Single-Phase Soft-Switching Unipolar PWM Rectifier ». Applied Mechanics and Materials 284-287 (janvier 2013) : 2439–44. http://dx.doi.org/10.4028/www.scientific.net/amm.284-287.2439.

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This paper proposed a novel single-phase soft-switching unipolar PWM rectifier (SSUPR) using a simple auxiliary resonant unit. All main switches of high-frequency arm operate at zero-voltage-switching (ZVS) turn-on, while the auxiliary switches operate at zero-current-switching (ZCS) turn-off. All main switches of low-frequency arm operate at 60 Hz to greatly reduce switching losses. Moreover, a soft-switching unipolar PWM strategy is used for the proposed soft-switching rectifier. This strategy results in a better input current waveform than for the bipolar PWM strategy. Furthermore, the proposed rectifier achieves a near unity power factor, a sinusoidal input current and a bidirectional power flow capability. Some experimental results of the proposed SSUPR, rated 500 W and operated at 40 kHz, are presented for verification.
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Sena, Gianluca, Roberto Marani, Gennaro Gelao et Anna Gina Perri. « A Comparative Study of Power Semiconductor Devices for Industrial PWM Inverters ». International Journal of Power Electronics and Drive Systems (IJPEDS) 7, no 4 (1 décembre 2016) : 1420. http://dx.doi.org/10.11591/ijpeds.v7.i4.pp1420-1428.

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The growing demand of energy translates into efficiency requirements of energy conversion systems and electric drives. Both these systems are based on Pulse Width Modulation (PWM) Inverter. In this paper we firstly present the state of art of the main types of semiconductors devices for Industrial PWM Inverter. In particular we examine the last generations of Silicon Carbide (SiC) MOSFETs and Insulated Gate Bipolar Transistors (IGBTs) and we present a comparison between these devices, obtained by SPICE simulations, both for static characteristics at different temperatures and for dynamic ones at different gate resistance, in order to identify the one which makes the PWM inverter more efficient.
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Thèses sur le sujet "Bipolar PWM"

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PEROTTI, MICHELE. « Software Solutions to Mitigate the Electromagnetic Emissions of Power Inverters ». Doctoral thesis, Politecnico di Torino, 2020. http://hdl.handle.net/11583/2842505.

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Azimifar, Seyed Ali. « Corrosion of bipolar plates in PEM fuel cells ». Thesis, University of Birmingham, 2015. http://etheses.bham.ac.uk//id/eprint/6285/.

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Laboratory and synchrotron X-ray fluorescence (XRF) have been used to investigate the microscopic and macroscopic distribution of metallic contaminants in membrane electrode assemblies (MEAs) which were used in proton exchange membrane fuel cell (PEM FC) stacks. The laboratory XRF results were consistent with the synchrotron XRF results. Higher levels of contaminants observed for the areas near to the coolant outlet than the areas near to the coolant inlet. The cathode side of MEAs showed higher levels of contamination than the anode side of the MEAs. Synchrotron XRF maps of MEAs generally showed higher levels of contaminants on the cathode side compared with the anode side. Fe was mainly observed in the cathode side microporous layers, whereas Ni, Cr and Cu were mostly accumulated in the cathode side or in the membrane. Synchrotron XRF maps of MEA plan views showed a crack-like distribution for Fe and Pt which were similar to cracks in the microporous layer of the MEAs. A novel electrochemical cell that simulated galvanic and crevice corrosion, temperature cycles for a PEM fuel cell, and pressure across the stacks was designed and used to discriminate between the corrosion behaviour of candidate coatings for bipolar plates.
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Lædre, Sigrid. « Investigation of metallic bipolar plates for PEM fuel cells ». Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for materialteknologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-16307.

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High cost and a short lifetime are the two main reasons why the PEM fuel cell is yet to be commercialized. The bipolar plate in a PEM fuel cell is alone responsible for about 45% of the cost and 85% of the total weight of a single cell. stainless steel has been suggested as material for the bipolar plate because of its good mechanical properties, easy manufacturing and relatively low price. A problem with stainless steel is the Chromium oxide film formed on the surface which causes a high contact resistance. In order to prevent this oxide formation, the stainless steel can be coated. Gold has been suggested as coating, but it is too expensive to be considered a viable alternative. The objective of this thesis was to investigate stainless steel as bipolar plate material for PEM fuel cells. In cooperation with SINTEF polarization tests were done on stainless steel bipolar plates with and without two different coatings; gold and Coating A. The tests were performed in H2SO4 electrolytes with different molarities and additives. Before and after each polarization test Interfacial Contact Resistance (ICR) measurements where done to see how the oxide layer on the stainless steel surface changed during polarization. Gold coated stainless steel was chosen as standard for both the polarization tests and the ICR measurements because of its corrosion resistance.The results obtained from both polarization tests and corresponding ICR measurements showed that the reproducibility was not as good as one had hoped, but this can be explained by low absolute values of the current densities. Gold coated steel proved to be a good standard for the ICR measurements, but due to pitting corrosion the corresponding polarization results were not as promising. The pH in an operating fuel cell was found to be approximately 3.5, and the tests done at different molarities showed that at a lower pH the oxide layer seemed to be thinner and the stainless steel surface thus became more exposed to corrosion. Additions of fluoride and chloride in the amounts expected in an operating fuel cell did not seem to cause any changes for neither the polarization results nor the contact resistance measurements. Stainless steel plates with Coating A showed very small changes in contact resistance after being put trough the polarization tests, but at low potentials the current densities in the polarization test were very high, indicating that components in the coating either catalyzed hydrogen evolution or were reduced themselves. Out of all the ICR measurements, gold coated stainless steel was the only plate satisfying US department Of Energy’s (DOE) resistance requirement for bipolar plates of less than 10 mΩ cm2. The stainless steel plates with Coating A were close to DOE’s requirements for both corrosion current and contact resistance. Non-coated stainless steel was ruled out as bipolar plate material due to high contact resistance measurements.
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Piri, Hossein. « Flow visualization in 3D printed PEM fuel cell bipolar plates ». Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/62259.

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In recent years, due to the public concern on global warming, both increasing energy efficiency and developing green energy become crucially important. Fuel cells can be one of the most suitable clean energy solutions for the environment because of its high energy conversion efficiency and near zero emissions of criteria air pollutants at the use stage. To increase the energy efficiency of fuel cells, effectively utilize the Pt catalyst and increase the fuel cell durability, the uniform distribution of the reactants over the fuel cell active area is of great importance. Over the last decade, many researchers have focused on developing flow field design to homogenously distribute the reactant and to decrease the pressure drop in the bipolar plates. However, most of the previous studies are in the stage of numerical simulation, and the few experimental studies have used very simple flow field geometries. Not to mention that complex transport phenomena inside a fuel cell make even the numerical simulation challenging and time consuming, which hinders the quick screening of proposed modifications and new designs. While the conventional fabrication techniques are expensive and time consuming, 3D printing is a very good rapid prototyping method that can be used both to validate the simulation results and to supplement the tedious simulation work. The question is whether the results from 3D printed flow fields could be as accurate and reliable as flow fields fabricated with conventional methods. In the present research, we investigated the applicability of 3D printing in validating the simulation results and as a fast screening method. State of the art designs for anode, cathode and water cooling BPPs proposed and fabricated using Polyjet 3D printing, SLA 3D printing and laser-cutter technologies and the pressure drop and velocity profiles were measured for each plate. The results demonstrated that SLA 3D printing has great promises to serve as a screening tool in modifying the flow field design, as well as in validating the simulation results.
Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate
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Kruszewski, Eric. « Investigation of Graphite Bipolar Plates for PEM Fuel Cell Performance ». Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/35835.

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The largest cost in manufacturing PEM fuel cells for automotive applications is due to the bipolar plate. The current graphite material used for the bipolar plate is very brittle and difficult to machine to the rigorous specifications needed for fuel cell stacks. This paper introduces the development of a fuel cell test stand for simultaneous testing of six individual fuel cells. To establish a long-term performance evaluation, the fuel cells incorporate a baseline graphite material that undergoes testing in the fuel cell environment. The graphite is an industry standard material that should not corrode when subjected to continual testing. The baseline model will be used in development of novel composite materials that will be tested under the same conditions for comparison to the graphite. Furthermore, the new materials and applied manufacturing methods could reduce the overall cost of fuel cell stacks in the future. Funding for this project was generously donated by the Virginia Center for Innovative Technology and the National Science Foundation.
Master of Science
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Husby, Håvard. « Carbon Based Coatings for Metallic Bipolar Plates in PEM Fuel Cells ». Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for kjemisk prosessteknologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-22407.

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Global warming and the climate changes are issues that concern everyone. The transition to other energy carriers than fossil fuels is a key barrier if we are to reduce our dependence on oil. Hydrogen is forecasted as the energy carrier of the future, and one of the most efficient ways to convert hydrogen to electrical, useful energy is to feed it to the anode side of a polymer electrolyte (PEM) fuel cell. Oxygen (usually in the form of air) is supplied to the cathode side and the only products are water, electricity and some heat.A key component in PEM fuel cells are the bipolar plates that facilitate gas flow, electron transfer, heat and water removal. The bipolar plates contribute greatly to both weight and cost of PEM fuel cells, and there is continuous development in making cheap, durable, light and efficient bipolar plates.In this work we attempted to coat stainless steel (316L) plates with a coating consisting of graphite and carbon black mixed with epoxy. The goal was to get a coating that conducts electrons while still protecting against corrosion. The coatings were sought further improved by adding Teflon particles. This was done to get the coating more hydrophobic, and thus a better corrosion protection of the underlying stainless steel substrate. Plates were glass blasted prior to coating to improve adhesion.Coatings were thinned with xylene and sprayed onto the plates with an air brush. The plates were then pressed in a ?Carver? hot-press to achieve minimum porosity. The coated plates were examined in a contact resistance apparatus, subjected to linear sweep voltammetry and chronoampereometry, the contact angles were measured, the surface roughness measured and SEM images are taken.Plates pressed at 2670 N cm-2 for 30 minutes with 4.8 vol% Zonyl in the coating performed best prior to electrochemical measurements both for the glass blasted plates and for the as-delivered plates. The contact resistances measured at 147 N cm-2 compaction pressure was 11.3 and 10.6 mOmega cm2 respectively. This is close to the goals set by DOE to reached by 2020 (10 mOmega cm2 at 138 N cm-2). The contact resistances for all coatings tested increased very much after the electrochemical testing, and all were far above the goals set by DOE.A correlation was found between the coating thickness and the current densities measured during the potentiostatic measurements. The current densities increased with increasing coating thickness. Possible mechanisms and reasons for this are discussed, and a combination of carbon corrosion and crevice corrosion is suggested as explanation.A possible method for anchoring the coating to the substrate while protecting the contact points from degradation during electrochemical measurements was suggested. By pressing the coating into carefully controlled voids, connections between the graphite in the coating and the metal substrate might be retained, even if the connection between main substrate surface and the coating is broken. This effect can explain the differences seen between the plates coated in the project work, and the metal sheets coated in this work.
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Hamilton, Philip John. « The development of PVD coatings for PEM fuel cell bipolar plates ». Thesis, University of Birmingham, 2014. http://etheses.bham.ac.uk//id/eprint/5107/.

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This work investigated the suitability of thin film, single and multi-layered coatings, by a Physical Vapour Deposition (PVD) process for polymer electrolyte membrane fuel cell bipolar plates. Due to the multifunctional nature of this particular component a comprehensive approach was used where several key properties were examined for coatings including: ZrN, TiN, CrN, Graphit-iC™, CrN+C, TiN+C and Au. Chemical etching and surface roughness were found to influence the Interfacial Contact Resistance (ICR) of the substrate; however, any observed effect was negated with the addition of a conductive coating. CrN+C and TiN+C multi-layer coatings showed a striking reduction in the ICR compared with the nitride only equivalents. The suitability of pre-coated PVD coatings for serial production via stamping was assessed in collaboration with an industrial partner. The coating durability was found to be influenced by several factors including coating type, thicknesses and position on stamped plate. The multi-layered TiN+C coating was found to noticeably improve the stampability compared to the TiN only coating. The corrosion resistance of the coatings was evaluated under simplified corrosion conditions. Under these conditions TiN+C was found to have two beneficial effects, improving the free corrosion potential and the stability of the carbon topcoat under startup/shutdown potentials.
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Mølmen, Live. « Materials Reliability in PEM Fuel Cells ». Licentiate thesis, Jönköping University, JTH, Material och tillverkning, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-52424.

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As part of the global work towards reducing CO2 emissions, all vehicles needs to be electrified, or fueled by green fuels. Batteries have already revolutionised the car market, but fuel cells are believed to be a key energy conversion system to be able to electrify also heavy duty vehicles. The type of fuel cell commercially available for vehicles today is the polymer electrolyte membrane fuel cell (PEMFC), but for it to be able to take a larger market share, the cost must be reduced while sufficient lifetime is ensured. The PEMFC is a system containing several components, made of different materials including the polymer membrane, noble metal catalyst particles, and metallic bipolar plate. The combination of different materials exposed to elevated temperature, high humidity and low pH make the PEMFC components susceptible to corrosion and degradation. The noble metal catalyst is one of the major contributors to the high cost. In this work, the latest research on new catalyst materials for PEMFCs are overviewed. Furthermore, electrodeposition as a simple synthesis route to test different Pt-alloys for the cathode catalyst in the fuel cell is explored by synthesis of PtNi and PtNiMo. The gas diffusion layer of the PEMFC is used as substrate to reduce the number of steps to form the membrane electrode assembly. In addition to cheaper and more durable materials, understanding of how the materials degrade, and how the degradation affects the other components is crucial to ensure a long lifetime. Finding reliable test methods to validate the lifetime of the final system is necessary to make fuel cell a trusted technology for vehicles, with predictable performance. In this work, commercial flow plates are studied, to see the effect of different load cycles and relative humidities on the corrosion of the plate. Defects originating from production is observed, and the effect of these defects on the corrosion is further analysed. Suggestions are given on how the design and production of bipolar plates should be made to reduce the risk of corrosion in the PEMFC.
Som en del av det globala arbetet med at reducera utsläppen av koldioxid måste alla fordon elektrifieras eller tankas med förnybart bränsle. Batterier har redan revolutionerat bilmarknaden, men bränsleceller är en viktig pusselbit för att också elektrifiera tunga fordon. Den typen av bränsleceller för fordon som finns tillgänglig på den kommersiella marknaden i dag är polymerelektrolytbränslecellen (PEMFC). För att PEMFC skall ta en större marknadsandel måste kostnaderna minskas och livslängden förlängas. PEMFC består av ett antal komponenter gjorda av olika material, bland annat polymer membran, ädelmetallkatalysator, och metalliska bipolära plattor. Kombinationen av olika material i tillägg till den höga temperaturen, hög fuktighet och låg pH gör att materialen i bränslecellen är utsatta för korrosion. Ädelmetallkatalysatorn är en av de kostdrivande komponenterna i bränslecellen. I denna studien presenteras en översikt över framstegen inom katalysatormaterial för PEM bränsleceller de senaste två åren. Sedan studeras elektroplätering som en enkel produktionsmetod för nanopartiklar av platina legeringar. Möjligheten att simultant plätera fler metaller, och att använda gasdiffutions-skiktet från bränslecellen som substrat för att reducera antal produktionsteg och därmed reducera kostnader, undersöks. Det möjliggör också snabb testning av olika legeringar för att identifiera den optimala sammansättningen med hög prestanda, lång livslängd och lite platina. I tillägg till att ta fram billigare och tåliga material är det viktigt att förstå hur materialen degraderar och hur degraderingen av ett material påverkar de andra komponenterna. Med den kunskapen kan man utveckla accelererade testmetoder för att bedöma livslängden av hela bränslecellen. Validerade testmetoder är viktigt för att styrka förtroendet till nya teknologier. I denna studien fokuseras det också på korrosion av bipolära plattor, och hur olika lastcykler och fuktnivåer som kan bli applicerad vid accelererad testning påverkar korrosionen. Också effekten av defekter från tillverkningen i den skyddande beläggningen analyseras med hänsyn till korrosion, för att ge mer insikt i hur bipolära plattor kan designas och produceras för att minska korrosionen.
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Cunningham, Brent David. « The Development of Compression Moldable Polymer Composite Bipolar Plates for Fuel Cells ». Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/26197.

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The development, design, and modeling of a rapid continuous processing scheme is developed to economically manufacture conductive polymer composite bipolar plates for fuel cells. Bipolar plates are required to possess several important properties for fuel cell operation, with the most sought after being electrical conductivity and mechanical strength. The polymer composite material generated at Virginia Tech is based on material generated by a wet-lay process and uses polyethylene terepthalate (PET) or polyphenylene sulfide (PPS) as the binder, although PPS is mainly used. In order to reach sufficient conductivity for use in generating bipolar plates, the polymer is doped with high levels of conductive graphite particles in the range of 70-80 wt%. The polymer system is reinforced with 6-9 wt% glass or carbon fibers. When compression molded into a solid, flat preform, the wet-lay material exhibits excellent bulk (in-plane) conductivity (> 250 S/cm). The material also exhibits tensile and flexural strengths of 57.5 and 95.8 MPa, respectively, higher than other polymer composite material being considered for bipolar plate production. However, formability and through-plane conductivity needs improvement. The laminate bipolar plates developed at Virginia Tech are made using wet-lay material in the core and a thermoplastic/graphite mixture on the surfaces. The wet-lay material provides mechanical integrity, while a powder form of PVDF or PPS and graphite mixture added to the surfaces to improve through-plane conductivity and formability. The manufacturing scheme for the production of laminate bipolar plates is based on the pre-consolidation of the wet-lay material, which establishes a solid, flat surface for the continuous addition of laminate powder. Because the laminate powder only requires heating, radiation heating is used in the process design to pre-heat the preform prior to compression molding. The heated preform passes underneath a press, where forming of channels takes place along with cooling of the bipolar plate. It is estimated that the entire process can take one minute to produce a bipolar plate. The cost of manufacturing a bipolar plate is estimated to be $8/kW, below the goal of $10/kW. The annual production is determined to be 250,000, with over 500,000 possible depending on certain design factors.
Ph. D.
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Desrosiers, Kevin Campbell. « Evaluation of Novel and Low-Cost Materials for Bipolar Plates in PEM Fuel Cells ». Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/35197.

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Bipolar plate material and fabrication costs make up a significant fraction of the total cost in a polymer electrolyte membrane fuel cell stack. In an attempt to reduce these costs, a novel manufacturing method was developed for use with composite materials. Conductive fillers were mixed with a polypropylene binder and molded into single cell monopolar plates. A fuel cell test stand, capable of testing six cells simultaneously, was used for long-term corrosion testing. In-situ tests took place in 5 cm2 active area fuel cells with cathode humidification. Using data from test cells containing graphite monopolar plates as a baseline, two composite formulations, were able to produce power at 66-79% of the baseline power. Power output from one cell remained in this range for over 200 hours, while the other sample experienced surface oxidation and eventually failed. With improvements in part conductivity coming from conductive polymers, this manufacturing technique holds the promise of producing monopolar and bipolar plates that could eventually be scaled up for use in fuel cell stacks.
Master of Science
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Livres sur le sujet "Bipolar PWM"

1

Jopke, J. Bctm Bipolar Circuits and Technology Meeting 1989/89Ch27714 Pbm. IEEE, 1989.

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2

Yeetsorn, Rungsima. A Review of Thermoplastic Composites for Bipolar Plate Materials in PEM Fuel Cells. INTECH Open Access Publisher, 2011.

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Singh, Deepan, dir. Neuro-behavioral Manifestations of Prader-Willi Syndrome. Cambridge University Press, 2022. http://dx.doi.org/10.1017/9781108886727.

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The behavioral issues experienced by individuals with Prader-Willi Syndrome (PWS) can be both surprising and overwhelming to clinicians and caregivers. Despite the distress and dysfunction posed by them, there are very few resources available to address these neuropsychiatric problems. This invaluable guidebook helps to identify and address the spectrum of behavioral issues faced by individuals with PWS. Written by a psychiatrist with unique expertise in the management of patients with this condition, this easy-to-read book explores practical details that will aid any clinician or caregiver. Chapters offer vivid case examples and clear guidance on both the behavioral and pharmacological management of issues such as anxiety, skin-picking, ADHD, disruptive behavior (including non-suicidal self-harm), mood disorders (including depression and bipolar disorder), and psychosis. Neuro-behavioral Manifestations of Prader-Willi Syndrome serves as an essential and practical companion for any caregiver or healthcare professional providing care to people with PWS.
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Chapitres de livres sur le sujet "Bipolar PWM"

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Blaacha, J., R. Aboutni et A. Aziz. « A Comparative Study Between a Unipolar and a Bipolar PWM Used in Inverters for Photovoltaic Systems ». Dans Lecture Notes in Electrical Engineering, 353–60. Singapore : Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-6259-4_38.

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Bloomfield, D., et V. Bloomfield. « PEM Fuel Cell Bipolar Plates ». Dans Modern Aspects of Electrochemistry, 1–35. New York, NY : Springer New York, 2007. http://dx.doi.org/10.1007/978-0-387-46106-9_1.

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Shaw, Leon L. « Carbon-Filled Polymer Blends for PEM Fuel Cell Bipolar Plates ». Dans Polymer Membranes for Fuel Cells, 1–25. Boston, MA : Springer US, 2008. http://dx.doi.org/10.1007/978-0-387-73532-0_12.

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Yasinskiy, Andrey, Peter Polyakov, Dmitriy Varyukhin et Sai Krishna Padamata. « Liquid Bipolar Electrode for Extraction of Aluminium and PGM Concentrate from Spent Catalysts ». Dans TMS 2021 150th Annual Meeting & ; Exhibition Supplemental Proceedings, 812–26. Cham : Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-65261-6_73.

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Yin, Jingtian, Takehisa Fukui, Kenji Murata, T. Hirabayashi, S. Yamamuro, M. Matsuda et M. Miyake. « A Novel Concept and Approach to Fabricate Protective KB/PVDF Composite Films on Metallic Bipolar Plates for PEM Fuel Cells ». Dans Ceramic Transactions Series, 325–31. Hoboken, NJ, USA : John Wiley & Sons, Inc., 2011. http://dx.doi.org/10.1002/9781118144145.ch50.

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« Bipolar Plates and Plate Materials ». Dans PEM Electrolysis for Hydrogen Production, 147–58. CRC Press, 2016. http://dx.doi.org/10.1201/b19096-11.

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Prassad, Venkatesan, Thorsten Hickmann, Engelke Martin, Klemp Eric et Derieth Thorsten. « Polypropylene Compounds for PEM-Electrolyzer Plates : Materials, Processing Methods, and Analysis of the Materials ». Dans Polypropylene Materials [Working Title]. IntechOpen, 2023. http://dx.doi.org/10.5772/intechopen.108777.

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Titanium and graphite-filled composites together with a polymer, such as polypropylene, are a suitable material for bipolar plates in PEM electrolyser applications. Similar to pure titanium metals, titaninium and graphite composite plates have quite good properties when mixed with polypropylene (PP). The plates have relatively low electrical resistance and can withstand the aggressive electrochemical environment encountered in an electrolyser. The main challenges here are resistance to oxygen, hydrogen, and complete. The conditions in operation are extreme. Above all, the comparatively high voltage and the fact that pure water is used generally cause problems for the materials. Besides pure titanium, composite materials can also be used. This chapter summarizes the most important requirements for the titanium-PP composite material. This material is used for bipolar plates. This is the basis for the characterization methods of titanium-based bipolar plates. The modern PP-based composites and their general properties are described, with a focus on improved long-term stability. In this chapter, the material fillers such as titanium and graphitic powders are analysed. The last deals with the way the electrical conductivity of the materials is measured and with in situ operation.
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Younas, Tanzila. « Bipolar plates for the permeable exchange membrane : carbon nanotubes as an alternative ». Dans PEM Fuel Cells, 71–89. Elsevier, 2022. http://dx.doi.org/10.1016/b978-0-12-823708-3.00004-3.

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« Low-Cost and Light Bipolar Plates of PEM Fuel Cell ». Dans Inaugural US-EU-China Thermophysics Conference-Renewable Energy 2009 (UECTC 2009 Proceedings), 1–6. ASME Press, 2009. http://dx.doi.org/10.1115/1.802908.paper50.

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Kühnemann, Lars, Thorsten Derieth, Peter Beckhaus et Angelika Heinzel. « Degradation of Bipolar Plates and Its Effect on PEM Fuel Cells ». Dans PEM Fuel Cell Failure Mode Analysis, 139–86. CRC Press, 2011. http://dx.doi.org/10.1201/b11112-7.

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Actes de conférences sur le sujet "Bipolar PWM"

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Trifa, V., Gh Brezeanu et E. Ceuca. « Unipolar PWM vs Bipolar PWM in Three Phase Block Commutation ». Dans 2020 International Semiconductor Conference (CAS). IEEE, 2020. http://dx.doi.org/10.1109/cas50358.2020.9267979.

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Jiang, Jun, Lu Zhao, Fucai Liu et Lin Kan. « Design of 1MHz-switching frequency bipolar current-mode PWM controller ». Dans 2010 10th IEEE International Conference on Solid-State and Integrated Circuit Technology (ICSICT). IEEE, 2010. http://dx.doi.org/10.1109/icsict.2010.5667310.

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Dahidah, Mohamed S. A., et Vassihos G. Agelidis. « Comparative evaluation of symmetrical and non-symmetrical bipolar SHE-PWM techniques ». Dans 2008 IEEE Power Electronics Specialists Conference - PESC 2008. IEEE, 2008. http://dx.doi.org/10.1109/pesc.2008.4592332.

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Shajith Ali, U., et V. Kamaraj. « Bipolar multicarrier PWM techniques for cascaded quasi-Z-source multilevel inverter ». Dans 2013 International Conference on Circuits, Power and Computing Technologies (ICCPCT). IEEE, 2013. http://dx.doi.org/10.1109/iccpct.2013.6528977.

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Bensraj, R., S. P. Natarajan et B. Shanthi. « Bipolar trapezoidal amalagated rectangular reference function for improved performance PWM multilevel inverter ». Dans 2012 International Conference on Computing, Electronics and Electrical Technologies (ICCEET). IEEE, 2012. http://dx.doi.org/10.1109/icceet.2012.6203908.

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Li, Peihe, Zeyu Zhang, Anwen Shen, Xin Luo et Qipeng Tang. « Combined Unipolar and Bipolar PWM for Braking Control of Brushless DC Motor ». Dans 2020 Chinese Automation Congress (CAC). IEEE, 2020. http://dx.doi.org/10.1109/cac51589.2020.9327726.

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Hammarstrom, Thomas. « The Implications on the PD Characteristics of Unipolar versus Bipolar PWM waveforms ». Dans 2019 IEEE Electrical Insulation Conference (EIC). IEEE, 2019. http://dx.doi.org/10.1109/eic43217.2019.9046597.

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Tyapin, Aleksey, et Evgeniy Kinev. « IGBT INVERTER WITH BIPOLAR SINUSOIDAL PWM FOR TWO PHASE LINEAR MHD MACHINE ». Dans CAD/EDA/SIMULATION IN MODERN ELECTRONICS 2019. Bryansk State Technical University, 2019. http://dx.doi.org/10.30987/conferencearticle_5e028210dbc298.14572422.

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Rai, Neerparaj, et Sandeep Chakravorty. « Hybrid-GA based multiple solutions for Selective Harmonic Elimination in Bipolar PWM waveforms ». Dans 2020 IEEE 5th International Conference on Computing Communication and Automation (ICCCA). IEEE, 2020. http://dx.doi.org/10.1109/iccca49541.2020.9250800.

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Dobrucky, B., M. Prazenica et J. Kassa. « Modelling and Simulation of Two-Phase System with Bipolar PWM Controlled Matrix Converters ». Dans Modelling, Identification, and Control. Calgary,AB,Canada : ACTAPRESS, 2010. http://dx.doi.org/10.2316/p.2010.675-105.

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Rapports d'organisations sur le sujet "Bipolar PWM"

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Wang, Conghua. Low Cost PEM Fuel Cell Metal Bipolar Plates. Office of Scientific and Technical Information (OSTI), mai 2013. http://dx.doi.org/10.2172/1082136.

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Adrianowycz, Orest, Julian Norley, David J. Stuart, David Flaherty, Ryan Wayne, Warren Williams, Roger Tietze, Yen-Loan H. Nguyen, Tom Zawodzinski et Patrick Pietrasz. Next Generation Bipolar Plates for Automotive PEM Fuel Cells. Office of Scientific and Technical Information (OSTI), avril 2010. http://dx.doi.org/10.2172/975485.

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