Developing Prognostic Models Using Duality Principles for DC-to-DC Converters

Within the field of Integrated System Health Management, there is still a lack of technological approaches suitable for the creation of adequate prognostic model for large applications whereby a number of similar or even identical subsystems and components are used. Existing similarity among a number of different systems, which are comprised of similar components but with different topologies, can be employed to assign the prognostics of one system to other systems using an inference engine. In the process of developing prognostics, this approach will thereby save resources and time. This paper presents a radically novel approach for building prognostic models based on system similarity in cases where duality principle in electrical systems is utilized. In this regard, unified damage model is created based on standard Tee/Pi models, prognostics model based on transfer functions, and remaining useful life (RUL) estimator based on how energy relaxation time of system is changed due to degradation. An advantage is that the prognostic model can be generalized such that a new system could be developed on the basis and principles of the prognostic model of other systems. Simple electronic circuits, dc-to-dc converters, are to be used as an experiment to exemplify the potential success of the proposed technique validated with prognostics models from particle filter

A New Four-Quadrant Inverter Based on Dual-Winding Isolated Cuk Converters for Railway and Renewable Energy Applications

The paper presents a new four-quadrant converter based on dual-winding isolated Cuk converters. The proposed converter can operate as a DC/DC converter, DC/AC inverter or AC/DC rectifier. The new converter offers important merits such as losses reduction, voltage boosting, flexible output voltage range, passive element reduction and galvanic isolation with small-size high-frequency transformers. If the proposed converter output is applied to a DC motor, providing the possibility of motoring, braking and regenerative braking if required. In addition, the converter offers the possibility to generate AC voltages and currents if it is employed in renewable energy systems as a DC/AC inverter. The paper presents the description of the converter with the associated mathematical analysis. Simulation results are obtained using MATLAB/SIMULINK software while experimental results are obtained using a scaled down prototype, controlled by TMS320F28335DSP

Reliability enhanced EV using pattern recognition techniques

The following paper will contribute to the development of novel data transmission techniques from an IVHM perspective so that Electrical Vehicles (EV) will be able to communicate semantically by directly pointing out to the worst failure/threat scenarios. This is achieved by constructing an image-based data communication in which the data that is monitored by a vast number of different sensors are collected as images; and then, the meaningful failure/threat objects are transmitted among a number of EVs. The meanings of these objects that are clarified for each EV by a set of training patterns are semantically linked from one to other EVs through the similarities that the EVs share. This is a similar approach to wellknown image compression and retrieval techniques, but the difference is that the training patterns, codebook, and codewords within the different EVs are not the same. Hence, the initial image that is compressed at the transmitter side does not exactly match the image retrieved at the receiver's side; as it concerns both EVs semantically that mainly addresses the worst risky scenarios. As an advantage, connected EVs would require less number of communication channels to talk together while also reducing data bandwidth as it only sends the similarity rates and tags of patterns instead of sending the whole initial image that is constructed from various sensors, including cameras. As a case study, this concept is applied to DC-DC converters which refer to a system that presents one of the major problems for EVs

Principle of Duality on Prognostics

The accurate estimation of the remaining useful life (RUL) of various components and devices used in complex systems, e.g., airplanes remain to be addressed by scientists and engineers. Currently, there area wide range of innovative proposals put forward that intend on solving this problem. Integrated System Health Management (ISHM) has thus far seen some growth in this sector, as a result of the extensive progress shown in demonstrating feasible and viable techniques. The problems related to these techniques were that they often consumed time and were too expensive and resourceful to develop. In this paper we present a radically novel approach for building prognostic models that compensates and improves on the current prognostic models inconsistencies and problems. Broadly speaking, the new approach proposes a state of the art technique that utilizes the physics of a system rather than the physics of a component to develop its prognostic model. A positive aspect of this approach is that the prognostic model can be generalized such that a new system could be developed on the basis and principles of the prognostic model of another system. This paper will mainly explore single switch dc-to-dc converters which will be used as an experiment to exemplify the potential success that can be discovered from the development of a novel prognostic model that can efficiently estimate the remaining useful life of one system based on the prognostics of its dual system

Current-source single-phase module integrated inverters for PV grid-connected applications

This paper presents a modular grid-connected single-phase system based on series-connected current-source module integrated converters (MICs). The modular configuration improves the reliability, redundancy and scalability of photovoltaic (PV) distributed generators. In this system, each PV panel is connected to a dc/ac inverter to permit individual Maximum Power Point Tracking (MPPT) operation for each panel. Thus, the harvested power from the PV system will increase significantly. There are four different inverter topologies suitable to be used as MICs with different performances in terms of filtering elements size, power losses, efficiency, output voltage range, and high frequency transformers’ size. For the MPPT control, the oscillating even order harmonic components should be eliminated from the inverter’s input side otherwise the maximum power cannot be extracted. The proposed modulation scheme in this paper will ease the control of inverter’s input and output sides. Therefore, the 2nd order harmonic in the input current can be eliminated without adding new active semiconductor switches. A repetitive controller coupled with proportional-resonant controllers are employed to achieve accurate tracking for grid side as well as input side currents. Comparisons and performance evaluations for the proposed MICs are presented and validated with 1 kVA prototype controlled by TMS320F29335 DSP

Desain dan Implementasi Bidirectional Cuk Konverter untuk Aplikasi Charging Station

Konverter DC-DC banyak dipakai dalam pembangkit listrik tenaga surya sebagai pengisi baterai pada charging station. Agar umur baterainya panjang maka konverter DC-DC harus mempunyai riak sekecil mungkin. Selain itu konverter DC-DC yang digunakan harus mempunyai efisiensi setinggi mungkin. Konverter DC-DC jenis boost memiliki penguatan yang tinggi. Sayangnya konverter DC-DC jenis boost mempunyai riak arus keluaran yang besar. Dalam tugas akhir ini, dilakukan desain dan implementasi modifikasi konverter DC-DC bidirectional jenis Cuk yang mempunyai arus masukan dan keluaran dengan riak yang rendah. Dengan mengambil terminal tegangan keluaran yang baru, maka konverter ini mempunyai penguatan yang tinggi seperti halnya konverter boost. Metoda analisis tegangan keluaran, riak arus induktor, dan riak arus kapasitor telah dilakukan. Metoda analisis yang dibuat telah diverifikasi lewat simulasi dan percobaan. Konverter ini juga sudah diuji kemampuan bidirectionalnya. Sehingga konverter hasil modifikasi konverter Cuk ini cocok digunakan untuk aplikasi charging station. ======================================================================================== DC - DC converters are widely used in battery charging station systems. In order to ensure the long ca pacitor and battery life , the DC - DC converter should have minimum input and output current ripples. Moreover, the DC - DC converter should have maximum efficiency . Boost DC - DC converter has a high voltage gain and low input ripple . Unfortunately the boost DC - DC converter ha s a large output current ripple. In this final project , design and implementation of modified bidirectional DC - DC converter type Cuk has low input and output current with low ripple. By taking the new output voltage terminal, this convert er has a high gain as well as the boost converter. The output voltage analysis method, the inductor current ripple, and the ripple current of the capacitor have been perfor med. The method of analysis has been verified by simulation and experiment. This con verter has also tested its bidirec tional ability. So this modified converter is suitable for charging station applications

Design of High-Gain DC-DC Converters for High-Power PV Applications

Renewable energy sources are penetrating the market in an ever increasing rate, especially in terms of Wind and Solar energies, with the latter being more suitable for the GCC region. Typically, Photovoltaic (PV) strings’ output voltage is limited to ~ 1500 V due to safety constraints, and thus requires boosting to higher DC levels (non-isolated step-up DC-DC transformer) suitable for High-Voltage DC (HVDC) and AC grid applications in order to provide the required DC-Link voltage level. Nevertheless, conventional non-isolated DC-DC converters provide a limited practical gain due to their parasitic elements. Other options include isolated DC-DC converters that utilize costly high-frequency transformers with limited power capability. Moreover, the isolation requirements of transformers in HVDC significantly increase the footprint of the converters. High-frequency transformers for high-power applications are hard to design and are usually associated with higher losses. Alternatively, connecting conventional DC-DC converters in different combinations can provide higher gains to the required levels, while maintaining the high efficiency requirements. This thesis proposes the cascade and/or series connection of DC-DC modules as a solution to the high-conversion ratio requirement, based on Cuk and Single-Ended Primary Inductor Converter (SEPIC) topologies, whose continuous input current is suitable for PV applications, and reduces the bulky capacitor filters at the input side. Detailed theoretical models of the proposed topologies are first derived, then their trends are practically verified by low power prototypes. Sensitivity analysis is also performed to assess the effect of small variations to the parasitic inductors’ resistances on the overall system gain, where the input inductor is found to have a considerable effect, especially at higher duty ratios (i.e. higher gains). High-power applications’ scenarios with their considerations are simulated to compare the different topologies and the results show a comparable efficiency of the proposed converters for a 1 –MW application with efficiencies higher than 90%

Unified approach for synthesis and analysis of non-isolated DC-DC converters

Transformational techniques unifying synthesis of two-state DC-DC converters and analytical synthesis techniques allowing generation of all possible converters meeting a certain criteria already exist. The analysis of a family of converters derived from a single converter cell has also been uni ed. Current waveforms generated by the family of converters were shown to be related. However, a concept or basic building blocks that facilitate uni ed synthesis, analysis, prediction of current waveforms and assignment of switch states over a very wide range of DC-DC converters is still lacking. This study will propose three 3-terminal basic building blocks and one 3-terminal lter block. It will be shown that between them, they are suf cient for realizing all non-isolated DC-DC converters excluding those with coupled inductors. The various DC-DC converters fall into those realized through cascade, stacked, stacked plus cascade, interleaved/paralleled or differential connection of the basic building blocks. A systematic approach for evaluating input-output current gains will be presented. Moreover, a basic building block will be shown to have xed switching states for proper operation. This gives rise to the generation of a unique set of current waveforms at the three terminals irrespective of where a basic building block is embedded. It has been shown that the effort and time needed to design DC-DC converters can be reduced as switching device stresses can be estimated without the need for tedious rst principle derivations.http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=6287639am2022Electrical, Electronic and Computer Engineerin

Diseño y análisis de convertidores DC/DC aislados

89 p. -- Bibliogr.: p. 74-76Este trabajo de fin de grado forma parte de un proyecto conjunto centrado en el diseño y análisis de convertidores DC/DC aislados. Se ha llevado a cabo una investigación para identificar topologías que permitan la implementación de un transformador real. Tras seleccionar los convertidores, se ha realizado un estudio exhaustivo del comportamiento del sistema para obtener un diseño acorde a las especificaciones establecidas. Se han realizado simulaciones abarcando diversos parámetros para comprender el control y la respuesta del convertidor ante distintas condiciones de entrada. Además, se ha efectuado una última simulación utilizando modelos de componentes reales. Estas etapas han permitido evaluar el sistema y obtener resultados precisos y realistas antes de la implementación práctica, utilizando modelos de componentes reales

Large step down voltage converters for desalination

One percent of the world's drinking water is currently desalinated, and this will have to increase to 14% by 2025. Desalination is energy intensive, having significant commercial and ecological implications. One of the most promising methods of desalination is capacitive deionisation which only uses 1kWh/m3 but requires a voltage of less than 1.8V at currents of up to 1000A This thesis produced hardware capable of creating 550A at a voltage of 1.8V, giving over a 1kW power rating, with an input voltage of 340V dc. The converter designed was a bidirectional asymmetrical half-bridge flyback converter allowing for isolation at these high step down ratios. The converter was used to charge a bank of 17,000F supercapacitors from 0V to 1.8V, with an initial charging step down ratio in excess of 340:1 falling to 190:1 as the load charged. A novel Asymmetrical Half-Bridge Coupled-Inductor Buck converter is presented as the ideal solution for large step-down ratios with analysis comparing the ability to efficiently step down a voltage with other common converters, the buck and flyback converters. A comparison between a single-ended coupled-inductor buck converter employing a buck-boost voltage clamp and the novel asymmetrical half-bridge coupled-inductor buck converter circuit shows that the asymmetrical half-bridge converter is a more efficient circuit as leakage energy is recovered; the switch voltages are clamped to within the dc voltage rating of the bridge and the control strategy is simple. Passive and active snubbers are reviewed for efficiency, switch ratings and management of the effects of leakage inductance and compared against the novel designs presented. In the desalination application isolation is required so the flyback circuit is used. An isolated three switch bidirectional converter is constructed using silicon carbide MOSFETs and diodes switching at 40kHz. The converter uses novel current measuring techniques, an on-board microprocessor and closed loop control designed into the final DC-DC converter.One percent of the world's drinking water is currently desalinated, and this will have to increase to 14% by 2025. Desalination is energy intensive, having significant commercial and ecological implications. One of the most promising methods of desalination is capacitive deionisation which only uses 1kWh/m3 but requires a voltage of less than 1.8V at currents of up to 1000A This thesis produced hardware capable of creating 550A at a voltage of 1.8V, giving over a 1kW power rating, with an input voltage of 340V dc. The converter designed was a bidirectional asymmetrical half-bridge flyback converter allowing for isolation at these high step down ratios. The converter was used to charge a bank of 17,000F supercapacitors from 0V to 1.8V, with an initial charging step down ratio in excess of 340:1 falling to 190:1 as the load charged. A novel Asymmetrical Half-Bridge Coupled-Inductor Buck converter is presented as the ideal solution for large step-down ratios with analysis comparing the ability to efficiently step down a voltage with other common converters, the buck and flyback converters. A comparison between a single-ended coupled-inductor buck converter employing a buck-boost voltage clamp and the novel asymmetrical half-bridge coupled-inductor buck converter circuit shows that the asymmetrical half-bridge converter is a more efficient circuit as leakage energy is recovered; the switch voltages are clamped to within the dc voltage rating of the bridge and the control strategy is simple. Passive and active snubbers are reviewed for efficiency, switch ratings and management of the effects of leakage inductance and compared against the novel designs presented. In the desalination application isolation is required so the flyback circuit is used. An isolated three switch bidirectional converter is constructed using silicon carbide MOSFETs and diodes switching at 40kHz. The converter uses novel current measuring techniques, an on-board microprocessor and closed loop control designed into the final DC-DC converter