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1	High Power Inverter EMI Characterization and Improvement by Auxiliary Resonant Snubber Inverter Tang, Yuqing 28 January 1999 (has links) Electromagnetic interference (EMI) is a major concern in inverter motor drive systems. The sources of EMI have been commonly identified as high switching dv/dt and di/dt rates interacting with inverter parasitic components. The reduction of parasitic components relies on highly integrated circuit layout and packaging. This is the way to deal with noise path. On the other hand, switching dv/dt and di/dt can be potentially reduced by soft-switching techniques; thus the intensity of noise source is reduced. In this paper, the relation between the dv/dt di/dt and the EMI generation are discussed. The EMI sources of a hard-switching single-phase PWM inverter are identified and measured with separation of common-mode and differential-mode noises. The noise reduction in an auxiliary resonant snubber inverter (RSI) is presented. The observation of voltage ringing and current ringing and the methods to suppress these ringing in the implementation of RSI are also discussed. The test condition and circuit layout are described as the basis of the study. And the experimental EMI spectra of both hard- and soft-switching inverter are compared. The effectiveness and limitation of the EMI reduction of the ZVT-RSI are also discussed and concluded. The control interface circuit and gate driver design are described in the appendix. The implementation of variable charging time control of the resonant inductor current is also explained in the appendix. / Master of Science soft switching noise reduction high power inverter EMI hard switching
2	Thermal Feasibility and Performance Characteristics of an Air-Cooled Axial Flow Cylindrical Power Inverter by Finite Element Analysis Tawfik, Jonathan Atef 01 May 2011 (has links) The purpose of the present study is to determine the thermal feasibility of an air-cooled power inverter. The inverter circuitry layout is designed in tandem with the thermal management of the devices. The cylindrical configuration of the air-cooled inverter concept accommodates a collinear axial air blower and a cylindrical capacitor with inverter cards oriented radially between them. Cooling air flows from the axial fan around the inverter cards and through the center hole of the cylindrical capacitor. The present study is a continuation of the thermal feasibility study conducted in fiscal year 2009 for the Oak Ridge National Laboratory to design a power inverter with a radial inflow cylindrical configuration. Results in the present study are obtained by modeling the inverter concept in computer simulations using the finite element method. Air flow rate, ambient air temperature, voltage, and device switching frequency are studied parametrically. Inlet air temperature was 50°C for all the results reported. Transient and steady-state simulations are based on inverter current that represents the US06 supplemental federal test procedure from the US EPA. The source of heat to the system comes from the power dissipated in the form of heat from the switches and diodes and is modeled as a function of the voltage, switching frequency, current, and device temperature. Since the device temperature is a result as well as an input variable, the steady-state and transient solution are iterative on this parameter. The results demonstrate the thermal feasibility of using air to cool an axial-flow power inverter. This axial inflow configuration decreases the pressure drop through the system by 63% over the radial inflow configuration, and the ideal blower power input for an inlet air flow rate of 540 cfm is reduced from 936 W to 312 W for the whole inverter. When the model is subject to one or multiple current cycles, the maximum device temperature does not exceed 164°F (327°F) for an inlet flow rate of 270 cfm, ambient temperature of 120°C, voltage of 650 V, and switching frequency of 20 kHz. Although the maximum temperature in one cycle is most sensitive to ambient temperature, the ambient temperature affect decays after approximately half the duration of one cycle. Of the parametric variables considered in the transient simulations, the system is most sensitive to inlet air flow rate. turbulent flow power electronics power inverter hybrid electric vehicle Energy Systems Heat Transfer, Combustion Mechanical Engineering Power and Energy
3	Méthodologie de conception numérique d'un module de puissance dédié à l'automobile en vue de l'optimisation des surtensions, des pertes et des émissions conduites / Methodology of numerical design of a power module dedicated to the automobile with optimizing overvoltages, losses and conducted emissions Daou, Hocine 08 February 2018 (has links) Le véhicule électrique (VE) s'inscrit actuellement dans un contexte industriel fortement corrélé aux contraintes environnementales. Un tel contexte où la minimisation des coûts est également vitale impose par conséquent des contraintes de développement et de réalisation. Les modules de puissance constituent un coût conséquent dans un système de conversion pour l'automobile. Nous nous plaçons dans le contexte des modules de puissance à IGBT en technologie silicium qui assurent les fonctions de conversion d’énergie (AC/DC ou DC/AC) pour des applications moyennes et fortes puissances. L’un des points les plus limitant de ces modules est l’aspect inductif de la maille de commutation. L’intégration de condensateurs de découplage (Ceq) au sein du module permet de réduire les effets des inductances parasites car ils offrent un chemin à basse impédance au courant commuté et augmentent la vitesse de commutation du composant. C’est cette solution que nous avons étudiée. Le but est de démontrer la faisabilité d’une telle solution couplée avec le choix optimal de la résistance de grille (Rg) des puces IGBT. Nous avons établi des règles de conception permettant la construction de modèles circuit d’un bras d’onduleur permettant l’intégration de fonction de découplage. Ce dernier nous a permis dans un premier temps de réduire les surtensions aux bornes des composants mais les pertes par commutation n’ont pas pu être améliorées significativement en comparaison à un module conventionnel. La démarche suivie pour aller plus loin a consisté à chercher un compromis entre les valeurs des condensateurs distribués dans le module et le choix des résistances de grille des puces IGBT. L’optimisation par algorithmes génétiques est la solution qui a été trouvée pour contourner les problèmes bloquants et améliorer significativement les performances du module. / Modern converter concepts demand increasing energy efficiency and flexibility in de-sign and construction. Considering that the dependency of the switching losses on various factors such as the switching voltage, switching current, stray inductance (Lstray) and the reverse recovery process of the freewheeling diode, various concepts have been developed to decrease power modules stray inductance for the purpose of loss reduction but with risk of exceeding the maximum rated blocking voltage. However, considering practical design requirement, lower stray inductance is not necessarily beneficial for the system. This leads to the question of tolerable size of parasitic inductance and best dI/di and dv/dt rate for low commutation losses and low voltage spikes. In this thesis, design methodology for a low inductive, Modern converter concepts demand increasing energy efficiency and flexibility in de-sign and construction. Considering that the dependency of the switching losses on various factors such as the switching voltage, switching current, stray inductance (Lstray) and the reverse recovery process of the freewheeling diode, various concepts have been developed to decrease power modules stray inductance for the purpose of loss reduction but with risk of exceeding the maximum rated blocking voltage. However, considering practical design requirement, lower stray inductance is not necessarily beneficial for the system. This leads to the question of tolerable size of parasitic inductance and best dI/di and dv/dt rate for low commutation losses and low voltage spikes. In this thesis, design methodology for a low inductive, Module de puissance pour l'automobile Inductances parasites Découplage intégré Surtension Pertes par commutation et rendement Automotive power inverter Stray inductance Voltage spike and losses Embedding capacitors Genetic algorithmes
4	Koncept nabíjecí stanice s možností off-grid provozu pro elektrokola / Concept of Charging Stations with off-grid Operation for Electric Bicycles Leitman, Valentín January 2017 (has links) This thesis deals with charging stations for electric bicycles powered by renewable energy. The aim of this work is to make a proposal for the hybrid charging stations for electric bicycles, which will work independently and, if necessary, will be backed up by a network. In this thesis is entered theoretical information on the issue of electric bicycles, the batteries, charging stations, the connectors of chargers, and photovoltaic systems. The practical part of this thesis is the basic design of the charging station and its design of the mathematical model of the individual parts in Simulink program, which are linked to the actual design of the charging station. In conclusion, this thesis deals with energy and economic analysis of the proposed system, therein included various methods of assessing investment recommendations of appropriate processing methods and overall assessment of the subject.
5	Development of a Cost-Effective, Reliable and Versatile Monitoring System for Solar Power Installations in Developing Countries : A Minor Field Study as a Master Thesis of the Master Programme in Engineering Physics, Electrical Engineering Trella, Fredrik, Paakkonen, Nils January 2016 (has links) This report is the result of a conducted Minor Field Study (MFS), to the greatestextent funded by the Swedish International Development Cooperation Agency(SIDA), in an attempt to design a system for evaluating smaller solar power systems indeveloping countries. The study was to the greater part conducted in Nairobi, Kenyain close collaboration with the University of Nairobi. The aim was to develop asystem that would use easily available components and keep the costs to a minimum,yet deliver adequate performance. The system would measure certain parameters of asolar power system and also relevant environmental data in order to evaluate theperformance of the system. Due to the specific competence of the collaboratinggroup at the University of Nairobi, a Kinetis Freescale K64-microcontroller with anARM-Cortex processor was selected as the core of the design. Components wereselected, schematics were drawn, a circuit board was designed and manufactured andsoftware was written. After 12 weeks a somewhat satisfying proof-of-concept wasreached at the end of the field study in Kenya. The project however proved howdifficult it is to go from first idea to a functional proof-of-concept during a limitedtimeframe, and also in an East-African country. The final proof-of-concept was testedat Mpala Research Centre in Kenya and despite containing some flaws proved that itwould indeed be possible to design a working system on the principles discussed inthis report. The system is open-source, so anyone may use and modify it. Solar Power PV Systems Embedded Systems Freescale Freedom Board Freescale Kinetis Kinetis K64 Measurement of Solar Power IV curves Electronics project management Open Source Designspark PCB ECAD CAD EMC PCB manufacturing Prototyping Minor Field Study MFS SIDA SystemC Kenya Nairobi University of Nairobi Justus Simiyu David Karibe Arnold Bett Mjomba Kale Boniface J M Muthoka International Science Programme ISP MIC79110YML LM2576 Island System Hybrid System Solar Charge Controller Solar Power Inverter State Space Model Model Based Development Platform Based Development Makers Just-Us Powers Just-Us ESP8266 Fona mini DHT22 ACS758 Model of Computation MOC Toner-Transfer Toner Transfer 3D-CAD Mpala Research Centre

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