620 Ingenieurwissenschaften und Maschinenbau
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Die Erfindung betrifft einen Energieübertrager (100) zur induktiven Energieübertragung von einem primären Schaltkreis (10) des Energieübertragers (100) an eine erste (5) und eine zweite (15) Spannungsdomäne eines sekundären Schaltkreises (20) des Energieübertragers (100) und zur Informationsübertragung vom sekundären Schaltkreis (20) zum primären Schaltkreis (10). Dabei umfasst der Energieübertrager (100): – einen Transformator (30), über den der primäre Schaltkreis (10) und der sekundäre Schaltkreis (20) induktiv miteinander gekoppelt sind und über den sowohl die Energieübertragung als auch die Informationsübertragung erfolgt; und – ein Amplitudenmodulationsmodul (50) zum Modulieren der Strom- und/oder Spannungsamplitude im sekundären Schaltkreis (20) mit Hilfe eines Amplitudenmodulationsschalters (55), wobei der Amplitudenmodulationsschalter (55) zwischen der ersten (5) und zweiten (15) Spannungsdomäne des sekundären Schaltkreises (20) angeordnet ist und ausgelegt ist, durch Öffnen und Schließen des Amplitudenmodulationsschalters (55) die Strom- und/oder Spannungsamplitude im primären Schaltkreis (10) zu ändern, um somit Information vom sekundären Schaltkreis (20) zum primären Schaltkreis (10) zu übertragen. Die vorliegende Erfindung betrifft ferner einen Gate-Treiber zum Schalten eines Leistungsschalters (500) und ein Verfahren zur induktiven Übertragung von Energie und zur kombinierten Informationsübertragung.
In this article an energy harvesting system for measuring the wind speed starting from 2 m/s (about 2 Bft) is presented, which uses the same source for measuring and supplying power (energy autarkic). The use of the same source for measurement and power supply increases the number of potential applications since needed power is present with the measuring signal. For the case of measuring the wind velocity, one might consider applications in tunnels, tubes, pipelines, air conditioning or for controlling clogging of filters. Bluetooth Low Energy (BLE) is chosen as radio technology, since it provides the possibility to realize a unidirectional communication; requiring only a single telegram (advertising telegram) for sending the measured value. A more complex establishment of communication required by WLAN or 6LoWPAN could therefore be avoided to significantly reduce the overall energy consumption. Since the advertisement telegram does not make any provision for security or against hacking in general, a security concept is presented which includes encryption and resilience against replay attacks in a unidirectional communication system.
To facilitate the presented concepts beyond wind sensors, the system is divided into three major modules namely the generator-sensor module, the radio module and the energy management module. Whereas the first two might be changed in different applications the energy management module could be reused in many different applications. It supplies and stores the needed energy and switches power on and off in a deterministic way to ensure the radio module can operate correctly.
This paper investigates the electrothermal stability and the predominant defect mechanism of a Schottky gate AlGaN/GaN HEMT. Calibrated 3-D electrothermal simulations are performed using a simple semiempirical dc model, which is verified against high-temperature measurements up to 440°C. To determine the thermal limits of the safe operating area, measurements up to destruction are conducted at different operating points. The predominant failure mechanism is identified to be hot-spot formation and subsequent thermal runaway, induced by large drain–gate leakage currents that occur at high temperatures. The simulation results and the high temperature measurements confirm the observed failure patterns.
The book provides suggestions on how to start using bionic optimization methods, including pseudo-code examples of each of the important approaches and outlines of how to improve them. The most efficient methods for accelerating the studies are discussed. These include the selection of size and generations of a study’s parameters, modification of these driving parameters, switching to gradient methods when approaching local maxima, and the use of parallel working hardware.
Bionic optimization means finding the best solution to a problem using methods found in nature. As evolutionary strategies and particle swarm optimization seem to be the most important methods for structural optimization, we primarily focus on them. Other methods such as neural nets or ant colonies are more suited to control or process studies, so their basic ideas are outlined in order to motivate readers to start using them.
A set of sample applications shows how bionic optimization works in practice. From academic studies on simple frames made of rods to earthquake-resistant buildings, readers follow the lessons learned, difficulties encountered and effective strategies for overcoming them. For the problem of tuned mass dampers, which play an important role in dynamic control, changing the goal and restrictions paves the way for multi-objective-optimization. As most structural designers today use commercial software such as FE-Codes or CAE systems with integrated simulation modules, ways of integrating bionic optimization into these software packages are outlined and examples of typical systems and typical optimization approaches are presented.
The closing section focuses on an overview and outlook on reliable and robust as well as on multi-objective optimization, including discussions of current and upcoming research topics in the field concerning a unified theory for handling stochastic design processes.
Saving energy and protecting the environment became fundamental for society and politics, why several laws were enacted to increase the energy-efficiency. Furthermore, the growing number of vehicles and drivers leaded to more accidents and fatalities on the roads, why road safety became an important factor as well. Due to the increasing importance of energy-efficiency and safety, car manufacturers started to optimise the vehicle in terms of energy-effciency and safety. However, energy-efficiency and road safety can be also increased by adapting the driving behaviour to the given driving situation. This thesis presents a concept of an adaptive and rule based driving system that tries to educate the driver in energy-efficient and safe driving by showing recommendations on time. Unlike existing driving-systems, the presented driving system considers energy-efficiency and safety relevant driving rules, the individual driving behaviour and the driver condition. This allows to avoid the distraction of the driver and to increase the acceptance of the driving system, while improving the driving behaviour in terms of energy-efficiency and safety. A prototype of the driving system was developed and evaluated. The evaluation was done on a driving simulator using 42 test drivers, who tested the effect of the driving system on the driving behaviour and the effect of the adaptiveness of the driving system on the user acceptance. It has been proven during the evaluation that the energy-efficiency and safety can be increased, when the driving system was used. Furthermore, it has been proven that the user acceptance of the driving system increases when the adaptive feature was turned on. A high user acceptance of the driving system allows a steady usage of the driving system and, thus, a steady improvement of the driving behaviour in terms of energy-efficiency and safety.
An integrated synchronous buck converter with a high resolution dead time control for input voltages up to 48V and 10MHz switching frequency is presented. The benefit of an enhanced dead time control at light loads to enable zero voltage switching at both the high-side and low-side switch at low output load is studied. This way, compact multi-MHz DCDC converters can be implemented at high efficiency over a wide load current range. The concept also eliminates body diode forward conduction losses and minimizes reverse recovery losses. A dead time resolution of 125 ps is realized by an 8-bit differential delay chain. A further efficiency enhancement by soft switching at the high-side switch at light load is achieved with a voltage boost of the switching node by dead time control in forced continuous conduction mode. The monolithic converter is implemented in an 180nm high-voltage BiCMOS technology. At V IN = 48V, V OUT = 5V, 50mA load, 10MHz switching frequency and 500 nH output inductance, the efficiency is measured to be increased by 14.4% compared to a conventional predictive dead time control. A peak efficiency of 80.9% is achieved at 12V input.
In recent years, significant progress has been made on switched-capacitor DC-DC converters as they enable fully integrated on-chip power management. New converter topologies overcame the fixed input-to-output voltage limitation and achieved high efficiency at high power densities. SC converters are attractive to not only mobile handheld devices with small input and output voltages, but also for power conversion in IoE, industrial and automotive applications, etc. Such applications need to be capable of handling widely varying input voltages of more than 10V, which requires a large amount of conversion ratios. The goal is to achieve a fine granularity with the least number of flying capacitors. In [1] an SC converter was introduced that achieves these goals at low input voltage VIN ≤ 2.5V. [2] shows good efficiency up to VIN = 8V while its conversion ratio is restricted to ≤1/2 with a limited, non-equidistant number of conversion steps. A particular challenge arises with increasing input voltage as several loss mechanisms like parasitic bottom-plate losses and gate-charge losses of high-voltage transistors become of significant influence. High input voltages require supporting circuits like level shifters, auxiliary supply rails etc., which allocate additional area and add losses [2-5]. The combination of both increasing voltage and conversion ratios (VCR) lowers the efficiency and the achievable output power of SC converters. [3] and [5] use external capacitors to enable higher output power, especially for higher VIN. However, this is contradictory to the goal of a fully integrated power supply.
A highly integrated synchronous buck converter with a predictive dead time control for input voltages >18 V with 10 MHz switching frequency is presented. A high resolution dead time of ˜125 ps allows to reduce dead time dependent losses without requiring body diode conduction to evaluate the dead time. High resolution is achieved by frequency compensated sampling of the switching node and by an 8 bit differential delay chain. Dead time parameters are derived in a comprehensive study of dead time depended losses. This way, the efficiency of fast switching DC-DC converters can be optimized by eliminating the body diode forward conduction losses, minimizing reverse recovery losses and by achieving zero voltage switching. High-speed circuit blocks for fast switching operation are presented including level shifter, gate driver, PWM generator. The converter has been implemented in a 180 nm high-voltage BiCMOS technology.
The power supply is one of the major challenges for applications like internet of things IoTs and smart home. The maintenance issue of batteries and the limited power level of energy harvesting is addressed by the integrated micro power supply presented in this paper. Connected to the 120/230 Vrms mains, which is one of the most reliable energy sources and anywhere indoor available, it provides a 3.3V DC output voltage. The micro power supply consists of a fully integrated ACDC and DCDC converter with one external low voltage SMD buffer capacitor. The micro power supply is fabricated in a low cost 0.35 μm 700 V CMOS technology and covers a die size of 7.7 mm². The use of only one external low voltage SMD capacitor, results in an extremely compact form factor. The ACDC is a direct coupled, full wave rectifier with a subsequent bipolar shunt regulator, which provides an output voltage around 17 V. The DCDC stage is a fully integrated 4:1 SC DCDC converter with an input voltage as high as 17 V and a peak efficiency of 45 %. The power supply achieves an overall output power of 3 mW, resulting in a power density of 390 μW/mm². This exceeds prior art by a factor of 11.
Der Wärmespeicher einer KWK-Anlage kann genutzt werden, um den Betrieb des BHKWs in die Zeiten des Stromverbrauchs zu verlagern. Die Ad-hoc-Zuschaltfunktion verbessert das Ergebnis gegenüber eines auf Basis von Prognosen erstellten Fahrplans. Zu beachten sind allerdings eine erhöhte Anzahl BHKW-Starts und erhöhte Wärmeverluste am Speicher. Die deutlich besten Ergebnisse werden für BHKW mit Leistungsmodulation erzielt.