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Ein virtuelles Kraftwerk ist ein Verbund von Energieanlagen, koordiniert von einem gemeinsamen Leitsystem, um eine bessere Ausnutzung wetterabhängiger Energiequellen oder die gemeinsame Vermarktung von erzeugtem Strom zu ermöglichen. Der Demonstrator Virtuelles Kraftwerk Neckar-Alb ist eine Demonstrationsplattform für Forschung und Lehre, die Anlagen auf dem Campus der Hochschule Reutlingen und verteilte Anlagen in der Region Neckar-Alb integriert.
The Virtual Power Plant Neckar-Alb is a demonstration platform for operation, optimization and control of distributed energy resources, which are able to produce, store or consume electric energy. A heterogeneous set of distributed energy devices has been installed at the Campus of Reutlingen University by the Reutlingen Energy Centre (REZ) of the School of Engineering. The distributed energy devices have been combined to local microgrids and connected to an operative central power plant with additional participants. The demonstration platform serves students, researchers and industry experts for education and investigation of new technologies, devices and software.
The coupling of the heat and power sector is required as supply and demand in the German electricity mix drift further and further apart with a high percentage of renewable energy. Heat pumps in combination with thermal energy storage systems can be a useful way to couple the heat and power sectors. This paper presents a hardware-in the-loop test bench for experimental investigation of optimized control strategies for heat pumps. 24-hour experiments are carried out to test whether the heat pump is able to serve optimized schedules generated by a MATLAB algorithm. The results show that the heat pump is capable of following the generated schedules, and the maximum deviation of the operational time between schedule and experiment is only 3%. Additionally, the system can serve the demand for space heating and DHW at any time.
Dieser Bericht fasst die wesentlichen Arbeiten und Ergebnisse zusammen, die in dem Verbundvorhaben „GalvanoFlex_BW“ im Kalenderjahr 2018 durchgeführt und erzielt wurden. Dazu lässt sich zunächst sagen, dass die Messwertaufnahme und –auswertung abgeschlossen ist. Es wurden verschiedene Messkampagnen bei der Fa. NovoPlan durchgeführt. Bei C&C Bark konnte man teilweise auf bestehende Daten zurückgreifen, die punktuell durch weitere Messungen ergänzt wurden. Bei der Fa. Hartchrom konnten aufgrund von Personalmangel keine Messungen durchgeführt werden. Die aufgenommenen Daten wurden in eine Effizienzbewertung überführt, aus der im Folgenden allgemeine Aussagen abgeleitet werden sollen. Dazu ist ein Simulationsprogramm aufgesetzt worden, das in der Lage ist, Prozessketten energetisch abzubilden und zu optimieren. Zudem sollen aus den Messdaten verbesserte Profile für den Wärmebedarf in den Unternehmen entwickelt werden, die daraufhin der KWK-Optimierung zur Verfügung gestellt werden. Im Zuge der Entwicklung und Bewertung stromoptimierter KWK- Strategien ist ein bestehendes Simulationsmodell entsprechend weiterentwickelt worden. Konkret wurde das Modell um eine verbesserte Lastprognose für Strom und Wärme für Industriebetriebe ergänzt, und das Optimierungsverfahren wurde um eine zweite Dimension erweitert. Während bislang allein die Optimierung der Eigenstromdeckung mit einer Begrenzung der BHKW-Starts als Nebenbedingung möglich war, ist jetzt die Kappung der elektrischen Lastspitze zusätzlich in der Zielfunktion integriert. Gerade bei Industrieunternehmen lässt sich auf diese Weise eine weitere, zum Teil nicht unerhebliche Energiekosteneinsparung erreichen, was durch die ersten Berechnungen anhand der drei im Reallabor vertretenden Betriebe bestätigt wird. Die Ergebnisse werden unter AP 8 (Umsetzung) diskutiert. Der Dialog mit weiteren Unternehmen und Institutionen außerhalb des Vorhabens konnte über die Branchenplattfom weitergeführt werden. In 2018 wurden zwei Veranstaltungen dieser Art durchgeführt, und im Frühjahr 2019 wird ein weiterer Workshop zu diesem Thema durchgeführt. Die sozialwissenschaftliche Begleitforschung wurde mit der zweiten Phase der Firmenbefragungen ebenfalls planmäßig weitergeführt. Mit Blick auf die Umsetzung eines BHKW-Konzeptes haben sich dabei zwei wichtige Punkte wie folgt gezeigt: Zum einen muss die umsetzende Firma eine gewisse „Energieeffizienz-Reife“ besitzen, die sich u.a. in der Erfahrung bei der Durchführung von Energieeffizienzmaßnahmen zeigt, da die Installation eines BHKWs eine äußerst komplexe Maßnahme darstellt. Zum anderen müssen andere unternehmensspezifische Kontextfaktoren hinzukommen, wie z.B. aus anderen Gründen durchzuführende bauliche Maßnahmen, so dass gewisse zeitliche Entscheidungsfenster entstehen, in denen die Umsetzung von KWK-Maßnahmen sinnvoll sind.
We present a compact battery charger topology for weight and cost sensitive applications with an average output current of 9A targeted for 36V batteries commonly found in electric bicycles. Instead of using a conventional boost converter with large DC-link capacitors, we accomplish PFC-functionality by shaping the charging current into a sin²-shape. In addition, a novel control scheme without input-current sensing is introduced. A-priori knowledge is used to implement a feed-forward control in combination with a closed-loop output current control to maintain the target current. The use of a full-bridge/half bridge LLC converter enables operation in a wide input-voltage range.
A fully featured prototype has been built with a peak output power of 1050W. An average output power of 400W was measured, resulting in a power density of 1.8 kW/dm³. At 9A charging current, a power factor of 0.96 was measured and the efficiency exceeds 93% on average with passive rectification.
The impact of pulse charging has been evaluated on a 400Wh battery which was charged with the proposed converter as well as CC-CV-charging for reference. Both charging schemes show similar battery surface temperatures.
Nowadays, the demand for a MEMS development/design kit (MDK) is even more in focus than ever before. In order to achieve a high quality and cost effectiveness in the development process for automotive and consumer applications, an advanced design flow for the MEMS (micro electro mechanical systems) element is urgently required. In this paper, such a development methodology and flow for parasitic extraction of active semiconductor devices is presented. The methodology considers geometrical extraction and links the electrically active pn junctions to SPICE standard library models and subsequently extracts the netlist. An example for a typical pressure sensor is presented and discussed. Finally, the results of the parasitic extraction are compared with fabricated devices in terms of accuracy and capability.
This study describes a non-contact measuring and parameter identification procedure designed to evaluate inhomogeneous stiffness and damping characteristics of the annular ligament in the physiological amplitude and frequency range without the application of large static external forces that can cause unnatural displacements of the stapes. To verify the procedure, measurements were first conducted on a steel beam. Then, measurements on an individual human cadaveric temporal bone sample were performed. The estimated results support the inhomogeneous stiffness and damping distribution of the annular ligament and are in a good agreement with the multiphoton microscopy results which show that the posterior-inferior corner of the stapes footplate is the stiffest region of the annular ligament. This method can potentially help to establish a correlation between stiffness and damping characteristics of the annular ligament and inertia properties of the stapes and, thus, help to reduce the number of independent parameters in the model-based hearing diagnosis.
This paper discusses the optimal control problem for increasing the energy efficiency of induction machines in dynamic operation including field weakening regime. In an offline procedure optimal current and flux trajectories are determined such that the copper losses are minimized during transient operations. These trajectories are useful for a subsequent online implementation.
Novel design for a coreless printed circuit board transformer realizing high bandwidth and coupling
(2019)
Rogowski coils offer galvanic isolation and can measure alternating currents with a high bandwidth. Coreless printed circuit board (PCB) transformers have been used as an alternative to limit the additional stray inductance if a Rogowski coil can not be attached to the circuit. A new PCB transformer layout is proposed to reduce cost, decrease additional stray inductance, increase the bandwidth of current measurements and simplify the integration into existing designs.
Due to the large interindividual variances and the poor optical accessibility of the ear, the specificity of hearing diagnostics today is severely restricted to a certain clinical picture and quantitative assessment. Often only a yes or no decision is possible, which depends strongly on the subjective assessment of the ENT physician. A novel approach, in which objectively obtainable, non invasive audiometric measurements are evaluated using a numerical middle ear model, makes it possible to make the hidden middle ear properties visible and quantifiable. The central topic of this paper is a novel parameter identification algorithm that combines inverse fuzzy arithmetic with an artificial neural network in order to achieve a coherent diagnostic overall picture in the comparison of model and measurement. Its usage is shown at a pathological pattern called malleus fixation where the upper ligament of the malleus is pathologically stiffened.
This study describes a non-contact measuring and system identification procedure for evaluating inhomogeneous stiffness and damping characteristics of the annular ligament in the physiological amplitude and frequency range without the application of large static external forces that can cause unnatural displacements of the stapes. To verify the procedure, measurements were first conducted on a steel beam. Then, measurements on an individual human cadaveric temporal bone sample were performed. The estimated results support the inhomogeneous stiffness and damping distribution of the annular ligament and are in a good agreement with the multiphoton microscopy results which show that the posterior-inferior corner of the stapes footplate is the stiffest region of the annular ligament.
It is expected that ongoing digitalisation will drive the merger between the manufacturing world and the internet world, possibly leading to a next industrial revolution, currently called “Industry 4.0”. The driving forces behind this development are new business opportunities and competition advantages arising from mass production customisation as well as rapid individual product development and manufacturing. Key factors of the development towards Industry 4.0 are discussed. Threats and opportunities arising from these developments for future production are discussed. Actual examples from real-time customized manufacturing of consumer products are given. As mechatronic systems and industrial robots are widely used in manufacturing and in particular in assembly, it is discussed how they can be connected to and used in digitalised industrial systems. Different examples of remote controlled systems are presented, like remote controlled KUKA robot for handling and quality control, PLC-controlled equipment, drive systems, FESTO handling system and others. The architecture of an assembly cell is presented, where industrial robots are set-up for batch-one production or can directly receive control / production information on-line and in real-time over the factory network. Methods for remote maintenance and monitoring of systems over the internet and production operator support over the internet are presented as well.
Improved inductive feed-forward for fast turn-on of power semiconductors during hard switching
(2019)
A transformer is used to increase the gate voltage during turn-on, thus reducing the necessary bias voltage of the gate driver. Counteracting the voltage dependency of the gate capacitance of high-voltage power devices, faster transitions are possible. The additional transformer only slighly increases the over-voltage during turn-off.
The Dual Active Bridge (DAB) is a very promising topology for future power converters. However, careless operation can lead to a DC component in the transformer current. The problem is further exacerbated when the phase shift changes during operation. This work presents a study of DC bias effects on the DAB with special regard to transient effects introduced by sudden shifts in the output load. We present a simple yet effective approach to avoid DC bias entirely.
IC layout automation with self-organized wiring and arrangement of responsive modules (SWARM)
(2019)
Focused on automating analog IC layout, the multi-agent-system Self-organized Wir ing and Arrangement of Responsive Modules (SWARM) combines the powers of pro-cedural generators and algorithmic optimization into a novel bottom-up meets top-down flow of supervised layout module interaction. Provoking self-organization via the effect of emergence, examples show SWARM finding even optimal placement solutions and producing constraint-compliant layout blocks which fit into a specified zone.
We propose a method for recognizing dynamic gestures using a 3D sensor. New aspects of the developed system include problem-adapted data conversion and compression as well as automatic detection of different variants of the same gesture via clustering with a suitable metric inspired by Jaccard metric. The combination of Hidden Markov Models and clustering leads to robust detection of different executions based on a small set of training data. We achieved an increase of 5% recognition rate compared to regular Hidden Markov Models. The system has been used for human-machine interaction and might serve as an assistive system in physiotherapy and neurological or orthopedic diagnosis.
This paper examines the deployment of Power to-X technologies in the US energy system through 2040. For this analysis, Power-to-X technologies have been added to an input database representing the US energy system as a single region, which is used in conjunction with an energy system optimization model called Tools for energy model optimization and analysis (Temoa). Detailed data for each individual technology, including water electrolysis, hydrogen compression and storage, chemical processing to synthetic natural gas (SNG) and methanol was collected and entered to the input database. Under a deep decarbonization scenario, Power-to-X is deployed beginning in 2035 under the assumption of no new nuclear power plants installed and a restriction on biodiesel production based on limited area for growing crops. The major portion of the hydrogen generated by electrolysis from excess PV- and wind-generated electricity goes into the production of methanol. This result suggests that Power-to-X is used to generate transport fuels in order to reduce CO2 emissions especially in this sector.
Efficient and robust 3D object reconstruction based on monocular SLAM and CNN semantic segmentation
(2019)
Various applications implement slam technology, especially in the field of robot navigation. We show the advantage of slam technology for independent 3d object reconstruction. To receive a point cloud of every object of interest void of its environment, we leverage deep learning. We utilize recent cnn deep learning research for accurate semantic segmentation of objects. In this work, we propose two fusion methods for cnn-based semantic segmentation and slam for the 3d reconstruction of objects of interest in order to obtain a more robustness and efficiency. As a major novelty, we introduce a cnn-based masking to focus slam only on feature points belonging to every single object. Noisy, complex or even non-rigid features in the background are filtered out, improving the estimation of the camera pose and the 3d point cloud of each object. Our experiments are constrained to the reconstruction of industrial objects. We present an analysis of the accuracy and performance of each method and compare the two methods describing their pros and cons.
A digital twin - a replica of energy devices - was established in the computing environment of MATLAB and Simulink. It simulates continuously their operation and is time synchronized and connected to the cenral energy management and control system of a virtual power plant. The model can be used as a platform for testing device performance in various conditions, working schedules and new optimization options.
The complexity of supply chains increases, especially due to the geographical spread of supplier and customer networks. In the connected and automated supply chains of the industry 4.0, even more nodes are incorporated in supply chains. This paper discusses the possible improvement of process quality in the industry 4.0 through the different blockchain and distributed ledger technologies. We derived hypotheses from a literature review and asked German blockchain experts from the industry to validate and discuss the hypotheses. We find that the different blockchain technologies and consensus algorithms have different strength with regard to quality improvement. One central finding is that IOTA, developed especially for the IoT and deemed the ’next evolutionary step’ is scalable and hence may increase the process efficiency, but at the same time is more vulnerable than other blockchain implementations, which again may reduce the overall process quality.