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Wide bandgap semiconductors, SiC and GaN-based power devices represent key candidates in the development of more efficient devices due to their superior electrical and thermal properties compared to silicon. To achieve maximal performance from WBG semiconductors, new packaging technologies and thermo-electric designs must be developed to ensure efficient and fast switching of devices while minimizing losses. The paper aims to investigate the thermal and mechanical behavior of new prepackage embedding technologies by finite element simulation. The focus is on insulated substrates including direct bonded copper (DBC) with various dielectrics such as AlN, Al 2O 3, Si3N 4 and new insulated metal substrates (IMS) with emphasis on commercially available materials and thicknesses. This study proposes a thermo-mechanical pareto-optimization methodology able to identify the best substrate configuration. The sintered silver layer (in both sides of the chip), which is the most prone to failure due to delamination, has been modelled with a temperature-dependent bilinear hardening model to account for plasticity. Pareto-optimization accounts for the module thermal resistance and the plastic strain or Von Mises Stress in the sintered layer. Results demonstrate that the best candidate from the thermo-mechanical point of view is the DBC with AlN showing a thermal resistance of 0.34 K/W, accumulative plastic strain of 0.18 % and Von Mises stress of 274 MPa. Finally, the parasitic inductance of multiple pre-packages is evaluated to scale the power of the module. Proper design allows to achieve a stray inductance as small as 1.23 nH for two prepackages and 2.85 nH for four prepackages.
Horizontal chip cracks have been reported in various scientific publications on PCB embedded power semiconductor devices. This study investigates in detail the root cause of the cracks. Experimental evidence indicates that the chip fractures in the mechanical grinding process during preparation of the cross-sections. Here, two different factors are relevant: First, the mechanical fracture strength of the semiconductor die decreases when grinding its edge. The use of P320 sand paper reduces the characteristic fracture strength from 719 MPa to 211 MPa. Second, the tensile stresses in the chip edge increase considerably when, part of the die and package is removed by grinding. Both effects together result in a failure probability of 100%. The use of finer grain sandpaper for target preparation helps to reduce the probability of generating horizontal chip cracks during cross-sectioning.
Safety of the Intended Functionality (SOTIF) addresses sensor performance limitations and deep learning-based object detection insufficiencies to ensure the intended functionality of Automated Driving Systems (ADS). This paper presents a methodology examining the adaptability and performance evaluation of the 3D object detection methods on a LiDAR point cloud dataset generated by simulating a SOTIF-related Use Case. The major contributions of this paper include defining and modeling a SOTIF-related Use Case with 21 diverse weather conditions and generating a LiDAR point cloud dataset suitable for application of 3D object detection methods. The dataset consists of 547 frames, encompassing clear, cloudy, rainy weather conditions, corresponding to different times of the day, including noon, sunset, and night. Employing MMDetection3D and OpenPCDET toolkits, the performance of State-of-the-Art (SOTA) 3D object detection methods is evaluated and compared by testing the pre-trained Deep Lea rning (DL) models on the generated dataset using Average Precision (AP) and Recall metrics.
The following paper points out the key role of IT in the future of car development. At the moment a fundamental change in the structure of automotive IT organizations can be observed. The fact that software update cycle in automotive, about 1 year, in comparison with Apple, Google or Tesla is too much. The entertainment industry is constantly proceeding ahead much faster than the automotive industry. On top of this, new emerging platforms like Apple CarPlay and Android Auto are providing the look and the feel of a mobile phone regarding the control of the car. The vehicle itself is getting more and more as an “ultimate mobile application or app”. This shows the need of speeding up the Time-to-Market of new innovations in automotive industry.
The structure of IT departments has to support these process. No wonder that CIOs of car manufacturers are looking for new structures in their IT departments that enable faster cycle update for automotive applications taking in consideration safety and security requirements.
This only represents a particular interest, as for Apple and Google, we can see that Google has already a fleet of 23 self-driving cars in place which has already autonomously driven more than one million miles with only 12 accidents on public roads and Apple is said to work under the project name "Titan" on its own electric car.
Another important aspect is the software running in the car itself, e.g. the software that “fuses” data from sensors into a comprehensible form: objects have to be accurately located in the environment model of the socalled ego vehicle as a basis for decisions making either by the driver himself or even by the software that can determine within a fraction of a second what the car is going to do. High definition maps also play a very important role in enabling autonomous driving, being developed and maintained by companies such as Nokia HERE, with accuracy of only a few centimeters are thought to be of strategic importance for Advanced Driver Assistance Systems and Self Driving Cars.
“We’re the engine room of the system,” says Mr. Ristevski, vice president of reality capture and processing for former Nokia’s mapping unit named HERE. To be independent from Apple and Google maps and with that from possible competitors, it is said to be the main reason why the German premium car manufacturer Audi, BMW and Daimler bought the online map service for about € 2.5 bn. This is only the first step in the restructuring of the automotive industry.
Trajectory Modelling for Autonomous Driving: Investigating the Artificial Potential Field Method
(2024)
Although the focus of autonomous driving is on maximizing safety and efficiency, comfort and familiarity will play a key role in the adoption of autonomous driving. Therefore, it is important to develop algorithms that can mimic human driving skills and adapt to individual driving styles. The potential field method (PFM) is an obstacle avoidance algorithm for autonomous driving that uses a repulsive potential field, as a environment model, to navigate the vehicle to the lowest risk potential. In this paper, the PFM is used in a overtake scenario at high speed, to test the impact of using prediction when calculating the ideal yaw rate. Analysis is done on how the potential field can be used for lane keeping while following a car and then for overtaking it. A driving simulator is used to record human driving data and compare it with automated driving using a PFM as is proposed by [3], with modifications to enable future prediction.
This paper reports the findings of an online between subject study that investigated the effectiveness of a non-humanoid socially assistive robot in providing positive reinforcement feedback to aid in improving performance on a cognitively demanding task. Four different feedback conditions were used, including verbal, expressive, neutral, and text-based feedback, to identify which type of feedback could positively influence behaviour. Results showed no significant differences in task performance, perceived workload or robot perception.
Produkte werden heutzutage immer variantenreicher und individueller. Für die industrielle Fertigung wachsen die Anforderungen, die Produkte effizient zu fertigen und schnell auf sich verändernde Marktbedingungen zu reagieren. Entsprechend rapide steigt die Nachfrage nach flexiblen Produktionslösungen, die sich möglichst autonom an die neuesten Marktanforderungen anpassen. Wandlungsfähige und modulare Produktionssysteme sollen es ermöglichen, auch bei großer Variantenvielfalt effizient zu produzieren - sogar bis zur Losgröße 1. Unterstützt wird die Produktion durch digitale Lösungen, die bereits an vielen Stellen zum Einsatz kommen.
Durch globale Unsicherheiten, steigende Variantenvielfalt und den Kundenbedarf nach ökologisch nachhaltig produzierten Produkten nehmen die Anforderungen an heutige Produktionssysteme stetig zu. Dies stellt bisherige Produktionsformen wie die Linienproduktion zunehmend vor Herausforderungen. Als hochflexible Produktionsform bietet sich die Matrixproduktion als alleinige oder in Kombination mit der Linie als hybride Produktionsform an.
The spectrometer-free chromatic confocal measurement technique enables 3D surface measurements with just one exposure and without scanning. To reduce the need for a spectrometer for the spectral analysis of the reflected light composition and thus the extraction of the local surface height, an optical spectral analysis unit is used. This unit determines the first momentum of the spectral composition reflected from the surface under probe for a large number of lateral measurement points simultaneously. This work investigates the impact of the spectral composition and light power of the light source on the sensitivity and accuracy of this method. A thorough optimization of the light source will be conducted, demonstrating the impact of various spectral compositions and light source power on the system performance, taking into account the system-related etendue. In addition, the optimization of the spectral transmission filter used in the optical spectral analysis unit and its influence on the accuracy and sensitivity of the system over the entire measurement range is shown.
The spectrometer free areal chromatic confocal metrology (ChromaCAM) is an optical 3D surface measurement technology, which allows a simultaneous measurement of a large array of measuring points within a single exposure. In this work, we investigate the accuracy of a first prototype sensor system utilizing this new singleshot 3D measurement technique. It is found that surface height measurement errors smaller 1μm within a total measurement range of about 1000 μm are achievable. Furthermore, several influential factors are investigated showing the advantages and limits of the presented system. Investigating different surface materials it is found that frame rates up to approximately 800 fps for highly reflecting surfaces and up to 30 fps for ceramics, aluminum, and plastics are achievable.
A considerable amount of enabling technologies are being explored in the era of fifth generation (5G) mobile system. The dream is to build a wireless network that substantially improves the existing mobile networks in all performance metrics. To address this 5G design targets, massive MIMO (multiple input multiple output) and mmWave (millimeter wave) communication are also candidate technologies. Luckily, in many respects these two technologies share a symbiotic integration. Accordingly, a logical step is to integrate mmWave communications and massive MIMO to form mmWave-massive MIMO which substantially increases user throughput, improve spectral and energy efficiencies, increase the capacity of mobile networks and achieve high multiplexing gains. Thus, this work analyses the concepts, performances, comparison and discussion of these technologies called: massive MIMO, mmWave Communications and mmWave-massive MIMO systems jointly. Besides, outcomes of extensive researches, emerging trends together with their respective benefits, challenges, proposed solutions and their comparative analysis is addressed. The performance of hybrid analog-digital beamforming architecture with a fully digital and analog beamforming techniques are also analyzed. Analytical and simulation results show that the low-complexity hybrid analog-digital precoding achieves all round comparable precoding gains for mmWave-Massive MIMO technology.
This study investigated the thermal performance of a packaging solution designed to manage the electrical isolation and cooling of high voltage ( ) SiC power semiconductor > 3300 V devices. The proposed packaging merges the ceramic substrate and the heat exchanger into a single component, streamlining the overall design. Specifically, a novel heat exchanger is developed for a multi-chip module (20 kV), utilizing a combination of jet impingement and channel- flow cooling techniques. Computational fluid dynamics (CFD) simulations and experimental validation are conducted on a multi-chip module to assess the thermal resistance of this new cooling solution. The results demonstrate a
low thermal resistivity of 0.118 cm2K/W, indicating the potential for improved cooling performance in high voltage and power density semiconductor applications.
The goal for solving the expansion planning (EP) problem in electrical systems involves the search for the optimal allocation of output power among available generators to serve the system load in a given time horizon. Currently, environmental aspects and the continuing search for alternative energy sources, push for the integration of wind power generators in the EP problem. In order to fulfill this new requirement, this paper developes a long-term energetic analysis for expansion planning under high wind power penetration scenarios in Colombia and its effect in neighboring countries. The simulations were developed using SDDP ™ software package, a tool based in stochastic dual dynamic programming technique for hydrothermal-wind least-cost dispatch.
The control of mechanical power in wind turbogenerators involves the participation of many subsystems. One of them is related to pitch mechanism, which usually employs conventional PI strategies. This paper presents an alternative for estimating the parameters of this PI controller, using Fuzzy Logic (FL). Matlab-Simulink™ software was used in order to verify the performance of the FL-based parameter estimator in some general cases.
One goal of research activities is finding ways to manage the growing complexity of embedded systems using self- configuration methods. While autonomous configuration could potentially be used in safety-critical and real-time systems, the basic requirements are not yet in place. This paper will outline a concept for the real autonomous configuration of TDMA-based communication processes, which currently does not exist. The paper initially addresses the TDMA-specific framework conditions and a potential solution. The issue of the mandatory a-priori known schedule is resolved using a generic schedule, because a simple method based on "free-slot-reserved-for- further-nodes" is not feasible. The most difficult part the startup was implemented through the generic schedule and an ID-based collision resolution process. To demonstrate the viability of the concept, the configuration method was implemented using a FlexRay communication system. This also satisfied the goal of eliminating the need for additional hardware and preserving the fault tolerant multimaster structure of the FlexRay system. The functionality of the concept was validated under different scenarios. The configuration times were analyzed, the results of which are also detailed here.
This work constitutes the second part of a study that aims to analyze the technical and economic implications of the penetration of wind power in the Colombian Interconnected System (SIN). In the previous part of the work, steady state studies were carried out (loading at transmission corridors, short circuit and the most important contingencies were applied). A summary with the main problems encountered and their respective solutions were proposed. In this second part, the same group of wind farms and time horizon were employed, while dynamic models were fit to ensure the proper operation of controls against the contingences. Using the software DigSilent™, studies of stability (with and without controls), power quality (flicker analysis), and voltage ride through capability (VRT) were addressed. Finally, technical recommendations and further work are presented.
This work is the first part of a study that aims to analyze the technical and economic implications of the penetration of wind power in the Colombian Interconnected system (SIN). Using the software DigSilent™, studies of steady state, contingencies and short-circuit were conducted in order to identify problems of stress, overload, voltage profiles, transmission bottlenecks and the most neuralgic elements for the operation of the proposed wind parks. Additional electrical studies, such as stability, power quality, voltage ride through capability, and the development of some indicators associated with the penetration of wind power in Colombia, will be addressed on a second part of this work.
This paper deals with the development of a system established on a telematic rehabilitation exerciser, a plug-PC and a real-time web-animation. An easy to use device, which allows a telematically controlled training at home is target of this project. It is thereby based on the diagnosis and therapy platform COMES ® of the Heinz Nixdorf-Lehrstuhl für Medizinische Elektronik of the Technische Universität München. In COMES ® mobile measured vital parameters are intelligently evaluated by an expert system before they are provided to the user along with medical information and trends. A Java application allows the real-time data, which is sent by a telematic exerciser and received over the Bluetooth interface of the plug-PC to be filtered and transmitted over a SQL-connection on, to a database. These data is retrieved by the animation and evaluated in form of a game. To visualize this web-animation, the screen of a potential terminal device is splitted in two and taking only a small horizontal part, this animation is shown on the screen. The other part could be filled by a TV-programm, Video or Skype window depending on the abilities of the terminal device which could be any device with an internet browser (e.g. a Smart TV).
No cost software tools and low cost measurement equipment enables improved teaching of circuit design. This paper presents results incorporating models, simulation and measurement together in teaching and laboratory. Comparison of circuit equations with measurement and simulation data addresses different learning styles and promotes advance in reflective judgment stages. It is closer to industrial work style and gives the student a feel for variations and accuracy in circuit design and measurement. A low cost electrical laboratory board (Electronic Explorer), a circuit simulator (LTSPICE) and a spreadsheet program can be used during lecture, laboratory and at home to align results and motivate students for a deep learning approach. This paper presents necessary modification for lecture and laboratory and looks at the results using these tools.