Teamtechnik (Germany)

Abstract With the ongoing efforts of integration of renewable energies in electric grids, synchronous condensers play an increasingly important role in ensuring a reliable and flexible power supply. A large number of these machines has already been installed or will be installed in the near future. One particularity of these machines in their most widely used horizontal shaft configuration is the lack of a well-defined static thrust force. Low static radial forces on journal bearings have been reported to result in high radial vibration amplitudes associated with oil whirl or oil whip, yet no such mechanism is known for thrust bearings. In this case study, we show that low axial loads on a combined radial and thrust bearing can lead to low-frequency axial vibrations of high amplitude, even resulting in a thrust bearing damage. With below 10 Hz, the frequency of these vibrations is below the range usually monitored with acceleration sensors, making it hard to detect using state-of-the-art monitoring equipment and thus a potential undiscovered thread to numerous machines already running in the field. We further introduce a method of mitigation that has proven to be successful in avoiding these vibrations and their unwanted effects on machine behavior and bearing lifetime with minimum modifications of the affected combined bearings.

The research project i‑WASP, a collaboration of specialized German and Austrian companies and research institutions, looks at the question of how complex processes on a conventional tunneling construction site can be automatically recorded, analyzed, and classified through the development of innovative solutions for data acquisition, transmission, and processing. A trained artificial intelligence will be able to automatically produce accurate minute diagrams based on accelerometer and positional data gathered from the construction machines.

Narrow line width lasers with high stability are a key enabling technology in high-impact applications such as quantum technologies and laser surgery. On the one hand, stabilizing such lasers implies the design of efficient Proportional-Integral-Derivative (PID) controllers. On the other hand, high end applications require PID controllers with very high regulation bandwidth, relocking feature and easy to adjust parameters. In order to tackle these challenges, we designed and enhanced a PID controller using the pipeline technique. This allowed us to improve the sample rate at which the controller operates. The designed PID has been successfully used in a VBG based external cavity for laser stabilization with ultra-narrow line width.

Results involving the use of a single nanoprobing contact are presented, on both a SiC planar MOSFET device, and a small system-in package. In both cases, mechanical polished samples were prepared, and then probed with a single contact. For the SiC MOSFET, the depletion zones were imaged while the samples were mounted on a 45 ° stub. Discussion of the different signals generated from Passive Voltage Contrast (PVC) and Electron Beam Induced Current (EBIC), as well as possible artifacts of sample grounding, are provided. For the package, Electron Beam Absorbed Current (EBAC) provided indication of connected features within the sample. The experiment showed the capability of measuring features across three orders of magnitude in size.

Methods for evaluation of junction in power semiconductor devices are discussed. An Insulated Gate Bipolar Transistor (IGBT) chip was selected for the experiment. Samples were alternatively mechanically polished, cleaved, or in a third case, sectioned with an experimental FIB (Focused Ion Beam) section. From here, sensitive Electron Beam Induced Current (EBIC) measurements were undertaken and results were compared. There was little difference in the ability to detect depletion zones between the techniques, indicating that Ga+ contamination or amorphization from the FIB did not prevent the collection of useful data from the p/n junctions. During the course of experimentation, it was determined that the pixel dwell time during electron beam stimulation had a strong effect on removing artifacts and increasing the contrast of the result. In the optimized analysis, the EBIC work crisply imaged the depletion zones of not only the P body / N- drift regions, but also the N+ / body regions in the same image. Additional observations were made to compare the different physical extents of the implant regions by Passive Voltage Contrast (PVC) versus the depletion zones from the EBIC results.

Abstract Power devices are now ubiquitous and integral in control of systems across various sectors of the economy. Silicon-based power devices still dominate in most of the applications although new materials and device architectures are becoming common in the next generation of devices. While several techniques to characterize the overall device properties are necessary, the fundamentals in several of these power devices such as Insulated Gate Bipolar Transistors (IGBTs) still rely on healthy junctions for optimal device performance. The technique of Electron Beam Induced Current (EBIC) is used to examine the depletion zones of the p/n junctions between drift and body regions of the device. Simple sample preparation methods such as cleaving the device allows quick cross-section evaluation of the device structure and electrical characterization using EBIC yields good data. The role of acceleration potential on depletion zone thickness is considered during the analysis of intact die and cross-sections. While low voltage EBIC provides images of the p/n junctions in cross-sections, it is found that high voltage (30 kV) EBIC images can also be used to image these same p/n junctions and therefore may point to a very quick line monitor or means for early failure analysis of these devices.

<p>Power-to-methane has been identified as a solution for quickly and effectively exploiting surplus electricity potential. Nevertheless, due to the current efficiencies, costs and sizes, it may not be suitable for local energy transitions. This article presents the results of two optimization models developed in Calliope for two case studies regions, with low wind levels in southern Germany with different electricity mixes. The optimization models simulate all available generation sources in the regions and their extensions with an additional Power-to-methane plant. The model minimizes the cost of the overall systems that meet the given demand including the gas, district heating, and electricity systems. Annual gas and district heating demand are generated based on collected data from industries, commerce, and households and standard load profiles, while annual electricity demand is obtained from public statistics. Besides, hourly electricity demand data from industries, commerce, and households are collected. Results are compared with scenarios using standard load profiles for electricity. The results show that the use of Power-to-methane is significantly affected by the load profiles used as well as the existing technological mix.</p>

External resonator diode lasers are the appropriate choice for species detection in application areas such as medicine, climate and industry due to their excellent properties, but have limitations in terms of high detection rates and commercial availability in the MIR region. Especially in the MIR region, many molecules have particularly strong absorption bands, which can result in very low detection limits and is therefore of particular interest. In this paper, we present our new ICbased laser chips with straight and curved waveguides with a center wavelength at 3.4 μm. These are integrated into an external resonator setup and characterized. The IC-based system enables continuous wave operation at room temperature over a wavelength range of 285 nm with several mW output power. With respect to the problem of high sampling rates, one promising technique is MEMS technology integrated as a tuning element in the external resonator structure. This enables planar drive control for high-frequency resonance-driven MEMS scanners, where the sampling frequency corresponds to the resonance frequency. These will be tested for their suitability and integrated into an ECDL setup and evaluated. Our work will address new requirements in terms of tuning range, output power, and acquisition rate.

Das Handhaben von Steuerungscode stellt einen erheblichen Kostenfaktor in Engineering-Projekten dar. Steuerungscodeprojekte sind häufig sehr komplexe und große Projekte, die teils aus hunderttausenden Verknüpfungen und Querverweisen bestehen. Der Entwurf von SPS-Software sollte daher zum Ziel haben, Aktivitäten wie Inbetriebnahme oder Wartung/Erweiterbarkeitzu unterstützen. Die Art und Weise, wie SPS-Code implementiert wird, steht diesen Zielen jedoch häufig entgegen. In diesem Beitrag wird beschrieben, wie sich bekannte Methoden anwenden lassen, um insb. die Struktur von SPS-Code analysieren zu können.

Software implements a significant proportion of functionality in factory automation. Thus, efficient development and the reuse of software parts, so-called units, enhance competitiveness. Thereby, complex control software units are more difficult to understand, leading to increased development, testing and maintenance costs. However, measuring complexity is challenging due to many different, subjective views on the topic. This paper compares different complexity definitions from literature and considers with a qualitative questionnaire study the complexity perception of domain experts, who confirm the importance of objective measures to compare complexity. The paper proposes a set of metrics that measure various classes of software complexity to identify the most complex software units as a prerequisite for refactoring. The metrics include complexity caused by size, data structure, control flow, information flow and lexical structure. Unlike most literature approaches, the metrics are compliant with graphical and textual languages from the IEC 61131-3 standard. Further, a concept for interpreting the metric results is presented. A comprehensive evaluation with industrial software from two German plant manufacturers validates the metrics' suitability to measure complexity.