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Vergleich der thermischen Eigenschaften unterschiedlicher insulated metal substrat-Leiterplatten
(2010)
LUVLED III – Optimierung eines Kühlkonzeptes zur Aktivluftkühlung eines Hochleistungs-UV-LED-Moduls
(2012)
In this paper a new teaching-learning-method including
the LEGO Mindstorms EV3 is presented. This computer
sciences course is part of the studies of mechatronics in the first
two semesters. The programming language being mediated is
ANSI-C. Computer science is not the most popular subject in
the interdisciplinary engineering field of mechatronics, therefore
the EV3 should be included to increase motivation. For the new
approach the former course – without the usage of EV3s – was
evaluated and a competency profile was identified. On this basis
a new didactical method was designed and implemented.
The EV3 is programmed with the IDE Eclipse and with a self
programmed plug-in.
Ein neues Lehr-/Lernarrangement als Einstieg in die C-Programmierung mittels LEGO Mindstorms EV3
(2015)
Ziel ist es, die Qualitätsverbesserung des Lehr-/Lernprozesses in der C-Programmierung
durch die Integration eines Roboters darzustellen. Dieses neue Konzept wurde bereits
teilweise in der Informatikveranstaltung (Studiengang Mechatronik – erstes und zweites
Semester mit 180 Minuten pro Woche) umgesetzt.
Conception of a LEGO Mindstorms EV3 Simulation for Programming in C in computer science courses
(2018)
Within the project SLOBATCO (Slovak-Bavarian Telescope Collaboration)
the Astronomical Institute of the Slovak Academy of Sciences and Aschaffenburg University of Applied Sciences collaborate in the development
and commissioning of scientific instrumentation for the new Ø1.3 m astronomical
telescope at the Skalnaté Pleso observatory. The joint project is funded by
the Bavarian Academic Center for Central, Eastern and Southeastern Europe
(BAYHOST). Planned technical work packages are targeting the filter wheel
software for the VIS camera, additional IR filters, and an upgrade of the mirror
coating facility by additional sputtering equipment.
Within the project SLOBATCO the question did arise, to what extend observatories have to rely on adequate
power quality, e.g. the perfect sinusoidal shape of supply voltage and current, in order to ensure safe
operation and accurate measurement results. International power quality standards are put in perspective
with requirement specifications. Telescope operators indicate partial or total loss of function of measurement instruments. Measurements
conducted during SLOBATCO project substantiate the need for power quality measurement campaigns.
Im Rahmen der Einführung des weltweiten Digitalrundfunks (Digital Radio Mondiale) im Frequenzbereich der Langwelle, Mittelwelle und Kurzwelle interessiert für Lang- und
Mittelwelle der Einfluss veränderlicher Parameter des Erdbodens auf das abgestrahlte Signal.
Zur Funknetzplanung werden die im “World Atlas of Ground Conductivities” aufgeführten Bodenleitfähigkeitskarten der International Telecommunication Union (ITU) herangezogen,
die jedoch nur einen groben Überblick über die Verhältnisse geben.
In dieser Arbeit soll untersucht werden, ob die Karten der Bodenleitfähigkeit in ihrer Ortsauflösung genügend genau dargestellt sind und ob gegebenenfalls durch die Anwendung
alternativer Verfahren genauere Karten erstellt werden können. Weiterhin sind unterschiedliche Verfahren zur Messung der Bodenleitfähigkeit bezüglich ihrer
Anwendbarkeit zu beurteilen.
Within the project SLOBATCO (Slovak-Bavarian Telescope Collaboration) the Astronomical Institute of the
Slovak Academy of Sciences and Aschaffenburg University of Applied Sciences collaborate in the
development and commissioning of the new Ø1.3 m astronomical telescope and the corresponding scientific
instrumentation. The project is funded by the Bavarian Academic Center for Central, Eastern and
Southeastern Europe (BAYHOST). Technical work packages are targeting filter wheel software for the VIS
camera, additional IR filters, and an upgrade of the mirror coating facility by additional sputtering equipment.
The electric power supply of astronomical observatories has to manage a conflict of
interest: Observatories are situated at remote locations, they have a high consumption
of electric power while measuring electric signals as sensitively as possible.
Within the project SLOBATCO, the question did arise, to what extent observatories
have to rely on adequate power quality, for example, the perfectly sinusoidal shape
of supply voltage and current, to ensure safe operation and accurate measurement
results. International power quality standards are put in perspective with requirement
specifications for observatories. This contribution describes themotivation, the
underlying mechanisms that lead to issues, comments on the challenge in power systems
engineering, proposes the instrumentation and installation, and interprets the
first results. Experimental results clearly motivate the need for further measurement
campaigns, as power-quality-related problems are common. A summary is provided
together with an outlook and a motivation for future measurement campaigns.
This paper will present different modulation schemes for optimizing the efficiency of low-voltage traction drives.
The converter of the vehicle automatically has to select the most suitable modulation or control scheme depending
on the present operating point in order to maximize the efficiency of the complete drive train. Furthermore, the
functional principles and algorithms of the individual modulation schemes will be presented, as well as the transition
between those schemes. Finally, the performance of the different schemes will be proved by dynamic and
stationary tests through fully automatized measurement analysis.
This paper reveals that the standard test procedures for the qualification and verification of traction battery systems are not sufficient in certain cases. In fact, realistic and application-oriented tests on the interaction among the complex battery subsystems are inevitable. To achieve these objectives, a high-performance test bench with the unique selling features of a high voltage/- and current range, extremely low ripple currents, and high dynamics is presented. For the operation of the applied multiphase current-sharing inverter for charging/discharging the device under test (DUT), special control algorithms, especially a current balancing control method, is introduced.
This contribution presents an innovative approximation method for the estimation of power quantities, fundamental waveforms, and RMS values of inverter-fed electrical machines. Typically, all these parameters are calculated as cyclically linked to the fundamental cycle of the voltages and currents of the inverter output or machine input. In order to increase the dynamic of this calculation, a suitable evaluation method based on the inverter switching cycle has been presented in previous publications. The present paper extends this switching frequency-based analysis by introducing additional quantities such as apparent and reactive power. Moreover, the paper describes the utilization of this analysis method for a power control of a dual two-level inverter-fed application.
In this contribution, a highly dynamic calculation method of power quantities and additional electrical quantities, such as RMS values and fundamental waveforms, is presented. Typically, these quantities are calculated periodically based on the fundamental cycle of the electrical voltages and currents. Hence, they are well defined during steady state conditions for ideal periodical waveforms. During dynamic balancing processes, electrical signals are non-periodic. In a strict sense, the fundamental cycle-based definitions, which are well known from the literature, are not valid for these transient signals. However, this paper presents a novel definition for the calculation of cycle-based quantities based on the switching cycle of the inverter output voltages. This definition delivers instantaneous results during transient balancing processes, whereby it approximates the conventional fundamental cycle-based definitions during the steady state.
This paper aims to present an optimized inverter topology, based on the dual two-level inverter, for feeding an open-end winding electrical machine with superconductive stator windings and a superconductive rotor. In order to achieve a high torque density, the stator windings are built of several superconducting tapes being in parallel. One inverter of the dual two-level inverter is equipped with powerful IGBT semiconductors and supplies the machine with energy. The second inverter is a low voltage MOSFET inverter that monitors the superconductor resistance (quench detection) and balances the current on the parallel superconductive tapes for guaranteeing an optimum operation with respect to the superconductive losses.
High Dynamic Power Balancing for Dual Two-Level Inverters during High-Speed Machine Operation
(2020)
This paper aims to present optimized square-wave modulation strategies for the dual two-level inverter, fed by two separate and galvanically isolated energy sources, to balance and control the energy distribution of both inverter systems. Especially for high-speed operation, the methods keep the machine in the required state while decreasing the switching operations to a minimum. Method one aims to compensate voltage fluctuations of variable DC-link voltages, while the second method ensures a symmetrical power distribution for the two inverter systems. In addition, both methods offer the possibility of adapting the amplitude of the usually fixed fundamental load voltage during square-wave modulation.
Electric drives in road vehicles with a battery as energy storage are about to be introduced to the mass market. In order to guarantee the quality and operational safety of battery-powered vehicles, considerable efforts must be made by car manufacturers and their suppliers. Since the properties of the batteries significantly determine the performance of the vehicles, special test benches with precise measuring systems are required for the accurate determination of the battery properties. The safety devices of the traction batteries must also be tested on high-performance test benches. In this paper the necessary test benches and the corresponding measuring systems are presented. Estimations of the measurement uncertainty and possibilities to increase measurement accuracy are presented.
The European Union-funded Advanced Superconducting Motor Experimental Demonstrator (ASuMED) project started in May 2017 with the purpose of demonstrating the benefits of a new, fully superconducting motor for reaching the targets established by the Flightpath 2050 plan. The project aims at a motor power density of 20 kW kg−1 using
a high-temperature superconducting (HTS) stator. The rotor will use HTS stacks operating like permanent magnets. A highly efficient cryostat for the motor combined with an integrated cryogenic cooling system and associated power converter will be used. This article provides a general overview of the prototype that is currently being assembled and that will be tested soon.
Im vorliegenden Beitrag wird die Topologie des Doppelzweipunktwechselrichters für die Anwendung in Elektrofahrzeugen vorgestellt. Dazu werden zunächst der Schaltungsaufbau und die spezifischen Schaltungseigenschaften näher erläutert. Anschließend werden relevante Vorteile dieser Topologie für die Anwendung in Elektrofahrzeugen dargestellt. Für die Kombination unterschiedlicher Energiequellen mit Hilfe des Doppelzweipunktwechselrichters werden geeignete Steuerungsstrategien präsentiert und anhand von realen Messungen am Systemprüfstand verifiziert. Mit dem Vorgestellten Verfahren kann die Leistungsaufteilung auf die beiden Energiespeicher und deren Energieaustausch untereinander mit hohem Freiheitsgrad gesteuert werden.
Advanced Control Methods for High Performance Dual Two-Level Inverter for Traction Application
(2021)
The topology of the dual two-level inverter in combination with an electrical machine with open-end winding is an optimal
solution for the realization of high requirements from the automotive sector for high-performance traction drives. In this
publication, methods for extending the operating range and improving output voltage and current quality are presented
for synchronous as well as asynchronous PWM methods for the entire operating range for this system configuration.
Emphasis is placed on symmetrical power sharing between the inverters to maximize the power range. Optimal integration
of the system is achieved by the topology-related possibility of DC fast charging of the energy storages from a DC grid
without an additional charging unit.
Terrestrial Trunked Radio (TETRA) is a worldwide common mobile communication standard, used by authorities and organizations with security tasks. Previous studies reported on health effects of TETRA, with focus on the specific pulse frequency of 17.64 Hz, which affects calcium efflux in neuronal cells. Likewise among others, it was reported that TETRA affects heart rate variability, neurophysiology and leads to headaches. In contrast, other studies conclude that TETRA does not affect calcium efflux of cells and has no effect on people's health.
In the present study we examine whether TETRA short- and long-term exposure could affect the electrophysiology of neuronal in vitro networks. Experiments were performed with a carrier frequency of 395 MHz, a pulse frequency of 17.64 Hz and a differential quaternary phase-shift keying (π/4 DQPSK) modulation. Specific absorption rates (SAR) of 1.17 W/kg and 2.21 W/kg were applied.
In conclusion, the present results do not indicate any effect of TETRA exposure on electrophysiology of neuronal in vitro networks, neither for short-term nor long-term exposure. This applies to the examined parameters spike rate, burst rate, burst duration and network synchrony.
Long‐term electromagnetic exposure of developing neuronal networks: A flexible experimental setup
(2016)
Neuronal networks in vitro are considered one of the most promising targets of research to assess potential electromagnetic field induced effects on neuronal functionality. A few exposure studies revealed there is currently no evidence of any adverse health effects caused by weak electromagnetic fields. Nevertheless, some published results are inconsistent. Particularly, doubts have been raised regarding possible athermal biological effects in the young brain during neuronal development. Therefore, we developed and characterized a flexible experimental setup based on a transverse electromagnetic waveguide, allowing controlled, reproducible exposure of developing neuronal networks in vitro. Measurement of S‐parameters confirmed very good performance of the Stripline in the band of 800–1000 MHz. Simulations suggested a flexible positioning of cell culture dishes throughout a large exposure area, as specific absorption rate values were quite independent of their position (361.7 ± 11.4 mW/kg) at 1 W, 900 MHz. During exposure, thermal drift inside cellular medium did not exceed 0.1 K. Embryonic rat cortical neurons were cultivated on microelectrode array chips to non‐invasively assess electrophysiological properties of electrogenic networks. Measurements were taken for several weeks, which attest to the experimental setup being a reliable system for long‐term studies on developing neuronal tissue.
Increasing data transmission rates and bandwidth both belong to the challenges of the development of high-performance wireless communication systems. Multi-channel communication systems commonly use several narrowband power amplifiers each one for a single communication channel. Lossy couplers are needed both to separate the different channels from each other at the amplifiers input and to combine the amplified signals on each channel at the output. This approach depicts a poor efficiency and is limited to a few number of channels since each channel duplication involves 3 dB losses due to couplers.
Alternatively, broadband radio frequency power amplifiers ensuring the simultaneous transmission of several carriers on a wide frequency range contribute to increase the cost and resource efficiency of transceivers in wireless communication systems. Gain flatness, a high output power, and low power levels of second and third order harmonics are required on the whole operating frequency range of the power amplifier in multi-carrier communication systems since overtones will degrade the quality of the communication.
The present work investigates the performances of a broadband push-pull power amplifier based on LDMOS transistors, the input matching network using a 8:1 transmission line transformer. For the first time investigations on harmonic distortions of the amplified signal when using a transformer with 8:1 impedance transformation ratio are presented. Characterisation of the power amplifiers performances is focused on gain flatness, output power, harmonic distortions and efficiency at 110 W.
Heutige Fahrzeuge erreichen durch den Einsatz elektronischer Systeme bisher ungeahnte Standards bei den Emissionen, der Sicherheit und dem Komfort. Der intensive Elektronikeinsatz schafft aber auch neue Probleme. Das Buch vermittelt die Grundlagen, um die Besonderheiten der Elektronik und Software im Kfz nicht nur zu kennen, sondern auch zu verstehen. Zusätzlich wird an Beispielen die Komplexität realer Systeme im Fahrzeug vorgeführt und gezeigt, welche Anwendungen durch die Elektronik erst möglich werden. Das Spannungsfeld zwischen Sicherheit, Zuverlässigkeit und Komplexität prägt in Verbindung mit branchenüblichen Abläufen das Vorgehen bei der Entwicklung, das ein in diesem Bereich tätiger Ingenieur verstehen muss.
汽车电子技术:硬件、软件、系统集成和项目管理
(2014)
Tested once, forever right
(2015)
EMC tests are usually done with electronic systems from production under comfortable environmental conditions. The scope of the paper is to analyze how aging and variable environment conditions, in particular temperature, change the electromagnetic behavior. For this purpose typical circuits are selected and sensitive parameters are identified.
Wir stellen einen neuen Ansatz vor um den Test und die Optimierung von Steuergeräten mit evolutionären Verfahren zu automatisieren und zu vereinfachen. Hierfür wurde ein Simulationsmodell des Testroboters erstellt, das den Optimierungsalgorithmen als Stützfunktion dient. Die Kombination der Simulation mit evolutionären Algorithmen erlaubt eine schnelle und systematische Auswertung der Roboterbewegungen, um optimierte Bewegungsparameter zu erhalten. Anhand der Optimierungsergebnisse kann die Fahrzeugsteuerung des Testfahrzeugs angepasst werden. Dieser neue Optimierungsansatz ist eine kostensparende, strukturierte und einfache Alternative zu aktuell eingesetzten Optimierungsprozeduren.
Comparison of Control Strategies by the Example of the Cooling Fan Control of a Mobile Machine
(2014)
In order to compare different control strategies the cooling system of a mobile machine has been chosen. The example control problem was to run the cooling system for m control variables and with n≤m correction variables in a way to minimize power in order to save energy and to reduce fan noise while maintaining sufficient cooling. The plant is nonlinear. Three different kinds of controllers have been investigated in several variations, i.e. fuzzy control, PI(D) and model predictive control (MPC). 14 different criteria have been used for evaluation. In many respects a linear controller with fuzzy prediction proved best, in particular the prediction model can handle nonlinear properties of the plant.
Das Projekt Etara (Entwicklungs- und Testzentrum für Automatisierung, Robotik und Automo-tive) des Zentrums für wissenschaftliche Services der Hochschule Aschaffenburg entwickelt als Referenzanwendung seiner Hardwareplattform einen Mobilroboter EtaBot für Erkundungs-zwecke. Dieser Roboter dient mittlerweile als Technologieträger für verschiedenste Sensorik, Aktorik und Algorithmen zur Berechnung von Wegen, Karten und vieles mehr. Viele Kompo-nenten des EtaBots sind bedeutende Verbraucher von elektrischer Energie welche nachein-ander analysiert und optimiert werden müssen. So fällt neben dem Rechner auch der Antrieb des EtaBots als großer Energieverbraucher auf, welcher unter anderem mit einer selbst entwickelten Ansteuerung optimiert werden kann.
In allen Projektphasen von der Spezifikation bis zum Test hilft die Verfügbarkeit einer simulierten Steuergeräteumgebung. Diese kann modellbasiert, softwarebasiert oder eine Hardwareumgebung sein. Bei der Hardware gibt es einfache Signalgeneratoren und Ersatzlasten als billigste Lösung. Die aufwändigste Lösung ist ein digitaler HiL-Simulator (Hardware in the Loop). Der Beitrag zeigt eine Lösung, die preislich und in der Benutzerfreundlichkeit einen Kompromiss zwischen diesen Extremen darstellt sowie aufgrund ihrer Modularität leicht anpassbar ist.
For the cooling system of a mobile machine with m control variables and with n≤m correction variables different control strategies have been investigated in order to minimize power to save energy and to
reduce fan noise with sufficient cooling. The plant is nonlinear and not identified. Three different
kinds of controllers have been investigated in several variations, i.e. fuzzy control, PI(D) and model
predictive control (MPC). 14 different criteria have been used for evaluation. In many respects a linear controller with fuzzy prediction proved best, in particular the prediction model can handle
nonlinear properties of the plant. A problem of advanced control schemes with unidentified plants
is the difficulty to prove stability.
Messtechnik und Prüfstände für Verbrennungsmotoren helfen, Kraftstoff einzusparen, Treibhausgase und Schadstoffe zu reduzieren, mit kleineren Motoren mehr Leistung abzugeben sowie Komponenten und Betriebsstoffe zu optimieren. Mit den Motoren und der Abgasgesetzgebung entwickelt sich auch die für die Entwicklung erforderliche mechanische, thermodynamische und Abgasmesstechnik weiter.
Dieses Buch vermittelt sowohl Studenten, als auch Planern und Betreibern in Industrie
und Wissenschaft das nötige umfangreiche Wissen, um Messungen an Motorenprüfständen durchführen zu können.
Manipulation von Abgaswerten
(2017)
Dieses kleine Buch stellt Hintergründe zum Abgasskandal dar, z. B. welche Schadstoffe kritisch sind, wie Motorsteuergeräte, Abgasrückführung und Abgasnachbehandlung funktionieren, wie Manipulationen auf dem Prüfstand möglich sind, mit welchen Fahrzyklen getestet wird und in welchem rechtlichen und politischen Umfeld dies lange Zeit unbemerkt mit unterschiedlichen Konsequenzen in der EU und den USA geschehen konnte. Es werden Maßnahmen vorgestellt, mit denen Fahrzeuge auch real gesetzliche Grenzwerte einhalten können und wie Manipulationen zukünftig rechtlich und politisch verhindert werden können. Dem Leser werden durch Literaturhinweise zusätzliche Details erschlossen.
Model Based EGR Control
(2017)
Almost stationary control of the correct EGR rate (Exhaust Gas Recirculation) is state of the art. More aggressive emission tests such as WLTP and RDE require a dynamic control of the EGR rate, otherwise a too low EGR rate results in increased NOx emissions, a too high EGR rate in particulate emissions. The difficulty in any EGR control is the missing plant knowledge; the EGR rate is controlled although the present EGR rate is not exactly known. EGR flow sensors are available, but due to additional costs they have not found a broad acceptance. A different approach for high pressure EGR investigated in this paper is a control using a second lambda sensor between EGR and inlet valves. This approach improves the dynamic response, but it might come with costs similar to an EGR flow sensor. Alternatively a model based approach can be used which shows high potential.
Experience in automotive industry shows that there are in particular two technical reasons why electronic systems in vehicles do not work as expected: software bugs and electromagnetic interference. Malfunctions are more than a mere annoyance, they can damage cars or other goods, injure people or kill people.
This book focuses on electromagnetic compatibility (EMC) keeping a close relation to functional safety as required by ISO 26262. It first introduces functional safety and EMC experts to automotive electronics. Since functional safety is still an emerging field, a primer might be useful to automotive engineers and EMC engineers as well. It then introduces to EMC. Signal and power integrity are topics which share the same fundamentals as EMC and are also relevant in some cases.
In automotive industry the V-model is still common to describe a development process. For this reason it is necessary to discuss the model and to integrate the safety life cycle and the EMC design flow into the model.
After the lecture the reader should be able to recognize and avoid hazards, to avoid expensive EMC problems, to simulate and test for EMC compliance of the car and its components and to fix problems. It helps to learn automotive EMC and functional safety and will stay a reference book after lecture. The book considers all levels from the whole car down to the single electronic control unit (ECU). EMC on integrated circuit level is considered in a few points which are relevant to vehicles. Additionally the charging infrastructure for electric cars is considered.
Robots can substitute for men in radioactively-contaminated areas. This is a suitable field to deploy robots for measurements, repair, or clearance, but development and test of such robots could be dangerous, because radiation sources need to be handled. To avoid these hazards in development or public demonstrations, safe alternatives to radiation samples have been sought using an already existing robot
(EtaBot). One proposed solution is an optical substitution (“light follower”), the other one a fully-digital simulation of the contaminated area and the robot movement inside it using a hardware-in-the-loop simulator (HiL).
Das Buch vermittelt die Grundlagen, um die Besonderheiten der Elektronik und Software im Kfz nicht nur zu kennen, sondern auch zu verstehen. Zusätzlich wird an Beispielen die Komplexität realer Systeme im Fahrzeug vorgeführt und gezeigt, welche Anwendungen durch die Elektronik erst möglich werden. Das Spannungsfeld zwischen Sicherheit, Zuverlässigkeit und Komplexität prägt in Verbindung mit branchenüblichen Abläufen das Vorgehen bei der Entwicklung, das ein in diesem Bereich tätiger Ingenieur verstehen muss.
Manipulation von Abgaswerten
(2021)
Dieses Buch stellt Hintergründe zum Abgasskandal dar, z. B. welche Schadstoffe kritisch sind, wie Motorsteuergeräte, Abgasrückführung und Abgasnachbehandlung funktionieren, wie Manipulationen auf dem Prüfstand möglich sind, mit welchen Fahrzyklen getestet wird und in welchem rechtlichen und politischen Umfeld dies lange Zeit geschehen konnte. Es werden Maßnahmen vorgestellt, mit denen Fahrzeuge auch real Grenzwerte einhalten können und wie Manipulationen zukünftig rechtlich und politisch verhindert werden können. Dem Leser werden durch Literaturhinweise zusätzliche Details erschlossen.
Manipulation von Abgaswerten
(2023)
Dieses kleine Buch stellt Hintergründe zum Abgasskandal dar, z. B. welche Schadstoffe kritisch sind, wie Motorsteuergeräte, Abgasrückführung und Abgasnachbehandlung funktionieren, wie Manipulationen auf dem Prüfstand möglich sind, mit welchen Fahrzyklen getestet wird und in welchem rechtlichen und politischen Umfeld dies lange Zeit unbemerkt mit unterschiedlichen Konsequenzen in der EU und den USA geschehen konnte. Es werden Maßnahmen vorgestellt, mit denen Fahrzeuge auch real gesetzliche Grenzwerte einhalten können und wie Manipulationen zukünftig rechtlich und politisch verhindert werden können. Dem Leser werden durch Literaturhinweise zusätzliche Details erschlossen.
Das Buch vermittelt die Grundlagen, um die Besonderheiten der Elektronik und Software im Kfz nicht nur zu kennen, sondern auch zu verstehen. Zusätzlich wird an Beispielen die Komplexität realer Systeme im Fahrzeug vorgeführt und gezeigt, welche Anwendungen durch die Elektronik erst möglich werden. Das Spannungsfeld zwischen Sicherheit, Zuverlässigkeit und Komplexität prägt in Verbindung mit branchenüblichen Abläufen das Vorgehen bei der Entwicklung, das ein in diesem Bereich tätiger Ingenieur verstehen muss.
内燃机测量技术和试验台架
(2023)
Kraftfahrzeug-Hybridantriebe
(2012)
Ecological comparison of soldering and sintering as die-attach technologies in power electronics
(2015)
In this study the method of life cycle assessment is used to perform a comparison of two die-attach technologies of power modules: silver sintering and common soldering with a tin–silver–copper solder. The goal of the study is to indicate which die-attach technique is more environmentally friendly. This is important in order to design future electronics more environmentally friendly.
Processing covers the manufacturing of the respective pastes, application of pastes, and mounting as well as the subsequent sintering or soldering, including cleaning of the soldered parts. The last step in the processing is a wire bonding process. The environmental impacts are expressed in CO2-equivalents and ReCiPe points and different variants are discussed: comparisons are made between considered pastes and between a soldered and a sintered power module, including consideration of lifetime. Concerning sintering, the influence of using recycled silver is analyzed more closely. The types of stages included in this life cycle assessment best fit a cradle-to-gate assessment, because usage, recycling, and disposal are not included. The software used is OpenLCA version 1.3.3, created by GreenDelta, and the database used is Ecoinvent version 2.2. In order to fill data gaps, electronics manufacturing companies were contacted, and our own calculations and measurements were applied.
The consideration of the wet film thicknesses of the soldering system and sintering system, respectively, results in very similar CO2-equivalent emissions for sinter paste and solder paste. Comparing the soldered power module to the sintered one shows minor to significant differences between the two systems which could easily be changed when changing circumstances and assumptions. But when considering the respective lifetimes of the joining technologies, sintering technology is clearly preferable to the conventional soldering technology. Using solely recycled silver for manufacturing of silver sinter paste reduces the CO2-equivalent emissions of one sintered power module by roughly 40%.
The results clearly show the dependence of outcomes on the initial settings. Consideration of lifetime has an enormous impact on the comparison of soldering technology to sintering technology. But the benefit of this life extension through the use of sintering technology is only useful when a long lifetime is required.
In this paper, we present two nondestructive characterization methods for the detection of voids in rear local contacts of passivated emitter and rear-type solar cells, namely scanning acoustic microscopy and computer tomography. We compare both methods and include a comparison with electroluminescence measurements. It is shown in this paper that voids can easily be detected with both measurement types without any sample preparation. We found a good match of scanning acoustic microscopy (SAM) and computer tomography (CT), which is presented for this purpose for the first time. The investigation was carried out for different aluminum pastes.