Die Entflechtung der Netze von den liberalisierten Bereichen der Energieversorgungsunternehmen (EVU) spiegelt sich in der Staatsaufsicht wider: Die liberalisierten Tätigkeitsbereiche werden dem freien Spiel der Kräfte ausgesetzt und unterliegen im Falle von Marktmacht der kartellrechtlichen Missbrauchsaufsicht. Demgegenüber wird der Netzbetrieb vollumfänglich und ausschließlich durch die Regulierungsbehörden überwacht. Trotz wesentlicher Unterschiede haben beide Formen der Staatsaufsicht die Funktion, unternehmerisches Handeln derart zu lenken, dass ein effektiver Wettbewerb im Energiemarkt möglich ist. Mit dem Ziel der Wettbewerbsförderung wird das Energierecht ständig Reformplänen unterzogen, ohne dass der Verordnungsgeber bereits bestehenden Konkretisierungsaufträgen umfassend nachkommen konnte. Unter Berücksichtigung der ausstehenden Rechtsverordnungen müssen Reformen ein angemessenes Verhältnis von staatlicher Steuerung und unternehmerischer Freiheit beachten. / Government supervision reflects the ongoing segregation of the distribution networks from the liberalised sectors of the power supply industry: The latter are exposed to full competition and are subject to the control of abusive practices by competition authorities. The networks, however, are controlled fully and exclusively by regulatory authorities. Despite their substantial differences, both forms of supervision are aimed at directing business activities to ensure effective competition on the energy markets. To promote competition, energy law is undergoing constant reform, but the required ordinances are yet to be enacted. New reform ideas should consider the outstanding ordinances and maintain an appropriate balance between government supervision and corporate freedom.

As process technologies continue their rapid advancement, transistor features are shrinking to almost unimaginable sizes. Some dimensions can be measured at the atomic level. One consequence of these smaller devices is that they have become more susceptible to deviations from nominal than previous process nodes. To illustrate, as few as one hundred atoms determine how much voltage is needed to turn a transistor on and off. With over two billion transistors on a single chip, it is easy to imagine how even the tiniest of variations can affect many transistors throughout the entire chip. To compensate for these deviations, chip designers add margin to their designs. Even more margin is then added for increased safety. All of this margin leads to chips that are slower than a nominal design would be. At the other end of the spectrum, these same deviations might result in chips that are faster than needed. However, faster is not always better, as these faster chips usually require more power. Even worse, these deviations sometimes produce chips that are both slower and use more power than a nominal design. TuneChip is designed to mitigate the effects of these process variations by speeding up areas of a chip that need to run faster while at the same time reducing power in parts of a chip that are operating faster than needed. TuneChip attacks the variation problem by changing the voltage on small areas of the chip in response to the type of variation for that particular area. Since voltage has a strong relationship to the speed of a chip, TuneChip can increase the speed of areas that need to go faster. At the same time, TuneChip can decrease the speed of other areas on the chip that are too fast. Even more important than speed for current designs, though, is power. Changing the voltage has a quadratic relationship with the amount of power consumed by that device. Specifically, a 10% reduction in supply voltage yields a 20% reduction in energy. Moreover, it is not only battery powered devices that benefit from reduced energy consumption; some high performance designs are limited by how much they can cool the chip. Cost-effective cooling technology is not scaling at anywhere near the same rate as transistor geometries. Reducing a chip’s power consumption also reduces excess heat. In order to selectively change the voltage of specific areas of the design, TuneChip starts by partitioning the chip into smaller blocks. A dual voltage design style with two voltage grids spans the entire chip. In order to best react to variations particular to an individual chip, each block is assigned a supply voltage only after manufacturing. First, the chip is tested at high voltage and high power in order to verify the correct functionality of that chip. If the chip passes its functionality testing, each individual block is tested to determine how fast it is operating. Blocks that need to run faster are configured to connect to the high supply voltage grid, and blocks that are able to run slower are configured to connect to the low supply voltage grid. The configurable block supply voltage connection is accomplished with pmos pass transistors that act like switches. By having only one pmos pass transistor switch turned on at a time, each block has a choice of two supply voltages. / text

published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

Η παρούσα διπλωματική εργασία πραγματεύεται τη θεωρητική ανάλυση και προσομοίωση διάταξης φόρτισης ηλεκτροχημικών συσσωρευτών για ηλεκτροκίνητο όχημα καθώς και την κατασκευή της για την πειραματική απόδειξη της ορθής λειτουργίας της. / This thesis deals with the theoritical analysis and simulation of power supply for electric vehicle and the construction for experimental evidence for the proper functioning of the power supply.

No description available.

Ring oscillators provide a central role in timing circuits for today?s mobile devices and desktop computers. Increased integration in these devices exacerbates switching noise on the supply, necessitating improved supply resilience. Furthermore, reduced voltage headroom in submicron technologies limits the number of stacked transistors available in a delay cell. Hence, conventional single-loop oscillators offer relatively few design options to achieve desired specifications, such as supply rejection. Existing state-of-the-art supply-rejection- enhancement methods include actively regulating the supply with an LDO, employing a fully differential or current-starved delay cell, using a hi-Z voltage-to-current converter, or compensating/calibrating the delay cell. Multiloop ring oscillators (MROs) offer an additional solution because by employing a more complex ring-connection structure and associated delay cell, the designer obtains an additional degree of freedom to meet the desired specifications. Designing these more complex multiloop structures to start reliably and achieve the desired performance requires a systematic analysis procedure, which we attack on two fronts: (1) a generalized delay-cell viewpoint of the MRO structure to assist in both analysis and circuit layout, and (2) a survey of phase-noise analysis to provide a bank of methods to analyze MRO phase noise. We distill the salient phase-noise-analysis concepts/key equations previously developed to facilitate MRO and other non-conventional oscillator analysis. Furthermore, our proposed analysis framework demonstrates that all these methods boil down to obtaining three things: (1) noise modulation function (NMF), (2) noise transfer function (NTF), and (3) current-controlled-oscillator gain (KICO). As a case study, we detail the design, analysis, and measurement of a proposed multiloop ring oscillator structure that provides improved power-supply isolation (more than 20dB increase in supply rejection over a conventional-oscillator control case fabricated on the same test chip). Applying our general multi-loop-oscillator framework to this proposed MRO circuit leads both to design-oriented expressions for the oscillation frequency and supply rejection as well as to an efficient layout technique facilitating cross-coupling for improved quadrature accuracy and systematic, substantially simplified layout effort.

The proposed research objective is to develop, test, and evaluate a mixer and charger-supply CMOS IC that derives and mixes energy and power from mixed sources to accurately supply a miniaturized system. Since the energy-dense source stores more energy than the power-dense source while the latter supplies more power than the former, the proposed research aims to develop an IC that automatically selects how much and from which source to draw power to maximize lifetime per unit volume. Today, the state of the art lacks the intelligence and capability to select the most appropriate source from which to extract power to supply the time-varying needs of a small system. As such, the underlying objective and benefit of this research is to reduce the size of a complete electronic system so that wireless sensors and biomedical implants, for example, as a whole, perform well, operate for extended periods, and integrate into tiny spaces.

High output electrical energy is obtained from photovoltaic (PV) systems subject to high irradiance. However, at high irradiance, the efficiency of PV systems drops due to increase of the temperature of the systems. In order to improve the efficiency of photovoltaic systems, much effort has been spent on developing hybrid photovoltaic thermal (PVT) systems using water as a coolant to withdraw heat from solar modules. This research is focused on the study of the behavior of hybrid PVT collectors using rectangular channel profiles which provide a large surface for heat exchange between PV panels and thermal collectors unlike the circular channel profile used in conventional PV systems. In hybrid PVT systems, coolant water circulates in a closed circuit by means of the thermosyphon phenomenon and the heat from this water is extracted from a storage tank and can be used in hot water systems instead of an electric geyser. Numerical models of water velocity in channels due to the thermosyphon phenomenon and the temperature of solar modules was developed and a system was designed for modest Durban household demand. A simulation was run for specific summer and winter days comparing a conventional PV system and a hybrid PVT system. The results were very encouraging, and demonstrated that the equipment is capable of extending the PVT application potential in the domestic sector where more than 40% of electricity cost is heating water. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2012.

In the context of modern aircraft systems, a major challenge is power conversion to supply the aircraft's electrical nstruments. These instruments are energized through a fixed-frequency internal power grid. In an aircraft, the available sources of energy are a set of variable-speed generators which provide variable-frequency ac voltages. Therefore, to energize the internal power grid of an aircraft, the variable-frequency ac voltages should be converted to a fixed-frequency ac voltage. As a result, an ac to ac power conversion is required within an aircraft's power system. This thesis develops a Matrix Converter to energize the aircraft's internal power grid. The Matrix Converter provides a direct ac to ac power conversion. A major challenge of designing Matrix Converters for aerospace applications is to minimize the volume and weight of the converter. These parameters are minimized by increasing the switching frequency of the converter. To design a Matrix Converter operating at a high switching frequency, this thesis (i) develops a scheme to integrate fast semiconductor switches within the current available Matrix Converter topologies, i.e., MOSFET-based Matrix Converter, and (ii) develops a new modulation strategy for the Matrix Converter. This Matrix Converter and the new modulation strategy enables the operation of the converter at a switching-frequency of 40kHz. To provide a reliable source of energy, this thesis also develops a new methodology for robust control of Matrix Converter. To verify the performance of the proposed MOSFET-based Matrix Converter, modulation strategy, and control design methodology, various simulation and experimental results are presented. The experimental results are obtained under operating condition present in an aircraft. The experimental results verify the proposed Matrix Converter provides a reliable power conversion in an aircraft under extreme operating conditions. The results prove the superiority of the proposed Matrix Converter technology for ac to ac power conversion regarding the existing technologies of Matrix Converters.

In the context of modern aircraft systems, a major challenge is power conversion to supply the aircraft's electrical nstruments. These instruments are energized through a fixed-frequency internal power grid. In an aircraft, the available sources of energy are a set of variable-speed generators which provide variable-frequency ac voltages. Therefore, to energize the internal power grid of an aircraft, the variable-frequency ac voltages should be converted to a fixed-frequency ac voltage. As a result, an ac to ac power conversion is required within an aircraft's power system. This thesis develops a Matrix Converter to energize the aircraft's internal power grid. The Matrix Converter provides a direct ac to ac power conversion. A major challenge of designing Matrix Converters for aerospace applications is to minimize the volume and weight of the converter. These parameters are minimized by increasing the switching frequency of the converter. To design a Matrix Converter operating at a high switching frequency, this thesis (i) develops a scheme to integrate fast semiconductor switches within the current available Matrix Converter topologies, i.e., MOSFET-based Matrix Converter, and (ii) develops a new modulation strategy for the Matrix Converter. This Matrix Converter and the new modulation strategy enables the operation of the converter at a switching-frequency of 40kHz. To provide a reliable source of energy, this thesis also develops a new methodology for robust control of Matrix Converter. To verify the performance of the proposed MOSFET-based Matrix Converter, modulation strategy, and control design methodology, various simulation and experimental results are presented. The experimental results are obtained under operating condition present in an aircraft. The experimental results verify the proposed Matrix Converter provides a reliable power conversion in an aircraft under extreme operating conditions. The results prove the superiority of the proposed Matrix Converter technology for ac to ac power conversion regarding the existing technologies of Matrix Converters.