This master’s thesis deals with the design of autonomous monitoring system electronics which will be used for diagnostics of the electromagnetic vibration generator developed at Brno University of Technology. This generator should be used in a practical application where frequent mechanical shocks are present, for example in vehicle or goods transportation. For such an application, the goal of the monitoring system is to find out whether generator is capable of producing enough electrical energy for smooth operation of wireless sensors used in similar applications. The first part of the thesis consists of the autonomous diagnostics system overview from both commercial and scientific spheres, brief description of the vibration generator used and also a summary of commercially available power management electronics. The next chapters present the detailed description of each functional element of energy harvesting system, the simulation of generator’s behaviour for optimal load in three different model applications and the most important part – design of the autonomous monitoring system. In the end, achieved results are evaluated and it is considered whether the shock-driven generator is suitable for use in a given application.

Dissertation thesis is focused on using alternative energy sources called energy harvesting. This thesis offers a solution to problems with autonomous powering of sensor networks if primary power source recovery is impossible. In these cases, energy of the external power (e.g. temperature, light, motion) should be used. Proposed solution should be especially used in the field of medical applications (e.g. cochlear implants, pacemakers, insulin pumps). Long time monitoring of the personal health status is also possible when employing automated sensor systems. In this work, there is state of art review relating to the low power energy sources for an alternative powering of sensor systems. It was observed that existing systems are almost prepared for the implementation of energy harvesting power sources. The energy harvesting power sources have been developed by numerous researcher teams around the world, but there are only a few variants of power management circuits for effective energy gaining, storing and using. This area has a huge potential for the next research. The issues regarding to the distribution of gained energy are solved on the complex level in the thesis. For these purposes, a new simulation model of the whole system (fully implantable artificial cochlea) including its subcircuits was developed in the SPICE environment. It connects independent subcircuits into a single comprehensive model. Using this model, a few novel principles for energy distribution (e.g. Charge Push Through technique) was developed. In the near future, these techniques are also applicable to the design of versatile sensor systems.

A new primary torque control concept for hydrostatics mobile machines was introduced in 2018 [1]. The mentioned concept controls the pressure in a closed circuit by changing the angle of the hydraulic pump to achieve the desired pressure based on a feedback system. Thanks to this concept, a series of advantages are expected [2]. However, while working in a Y cycle, the primary torque controlled wheel loader has worse performance in efficiency compared to secondary controlled earthmover due to lack of recuperation ability. Alternatively, we use deep learning algorithms to improve machines’ regeneration performance. In this paper, we firstly make a potential analysis to show the benefit by utilizing the regeneration process, followed by proposing a series of CRDNNs, which combine CNN, RNN, and DNN, to precisely detect Y cycles. Compared to existing algorithms, the CRDNN with bidirectional LSTMs has the best accuracy, and the CRDNN with LSTMs has a comparable performance but much fewer training parameters. Based on our dataset including 119 truck loading cycles, our best neural network shows a 98.2 % test accuracy. Therefore, even with a simple regeneration process, our algorithm can improve the holistic efficiency of mobile machines up to 9% during Y cycle processes if primary torque concept is used.

No description available.

The introduction of hybrid powertrains has made it possible to utilise unconventional engines as primary power units in vehicles. The free-piston energy converter (FPEC) is such an engine. It is a combination of a free-piston combustion engine and a linear electrical machine. The main features of this configuration are high efficiency and a rapid transient response. In this thesis the free-piston energy converter as part of a hybrid powertrain is studied. One issue of the FPEC is the generation of pulsating power due to the reciprocating motion of the translator. These pulsations affect the components in the powertrain. However, it is shown that these pulsations can be handled by a normal sized DC-link capacitor bank. In addition, two approaches to reduce these pulsations are suggested: the first approach is using generator force control and the second approach is based on phase-shifted operation of two FPEC units. The latter approach results in higher frequency and lower amplitude of the pulsations, which reduce the capacitor losses. The FPEC start-up requirements are analysed and by choosing the correct amplitude of the generator force during start-up the energy consumption can be minimised. The performance gain of utilising the FPEC in a medium sized series hybrid electric vehicle (SHEV) is also studied. An FPEC model suitable for vehicle simulation is developed and a series hybrid powertrain, with the same performance as the Toyota Prius, is dimensioned and modelled. Optimisation is utilised to find a lower limit on the SHEV's fuel consumption for a given drivecycle. In addition, three power management control strategies for the FPEC system are investigated: two load-following strategies using one and two FPEC units respectively and one strategy based on the ideas of an equivalent consumption minimisation (ECM) proposed earlier in the literature. The results show a significant decrease in fuel consumption, compared to a diesel-generator powered SHEV, just by replacing the diesel-generator with an FPEC. This result is improved even more by using two FPEC units to generate the propulsion power, as this increases the efficiency at low loads. The ECM control strategy does not reduce the fuel consumption compared to the load-following strategies but gives a better utilisation of the available power sources. / QC 20101116

No description available.

Tesis por compendio / [ES] Dos aspectos críticos en la operación de una microrred son las estrategias de control y gestión de potencia implementadas, las cuales son esenciales para proporcionar su buen funcionamiento. La aplicación adecuada de dichas estrategias permite compensar los desequilibrios de potencia causados por la discontinuidad de la generación y de la demanda de energía en las microrredes. En este sentido, el objetivo global de estas estrategias de gestión es equilibrar adecuadamente el flujo de potencia en la microrred, mediante la aplicación de diferentes algoritmos que permiten cumplir con los criterios de estabilidad, protección, balance de potencia, transiciones, sincronización con la red y gestión adecuada de la microrred. En el caso de microrredes de pequeña escala de potencia con bajo número de generadores y sistemas de almacenamiento distribuidos, las estrategias de control centralizado ofrecen un alto nivel de flexibilidad para lograr funcionalidades avanzadas en la microrred y una adecuada distribución de la potencia entre los convertidores que la conforman. Esta tesis se ha enmarcado en el contexto de algoritmos de gestión centralizada de potencia de una microrred de generación distribuida en modo conectado a red. Los algoritmos presentados se pueden aplicar a los convertidores de potencia conectados al bus DC de una microrred AC/DC híbrida o en una microrred de DC, donde el despacho de potencia es observado y gestionado por un controlador central. Este último adquiere datos del sistema mediante una infraestructura de comunicaciones y estima la potencia que gestionará cada uno de los convertidores de potencia, sistemas de almacenamiento y cargas en funcionamiento. En este estudio se muestra la validación experimental de las estrategias de gestión aplicadas en la microrred desde el enfoque del comportamiento de los convertidores de potencia, de las baterías y las cargas ante dicha gestión. Se verifica la estabilidad de la microrred sometiendo a los convertidores a diferentes escenarios de funcionamiento. Estos escenarios pueden ser fluctuaciones en la irradiación, la demanda, el estado de carga de las baterías, los límites máximos de exportación/importación de potencia desde/hacia la microrred hacia/desde la red principal y de la tarifa eléctrica. Adicionalmente, se propone un sistema de almacenamiento de energía en baterías encargado de mantener el equilibrio de potencia en el bus de DC de la microrred que permite aprovechar las fuentes de generación renovables presentes en la microrred y maximizar el tiempo de servicio de las baterías mediante la aplicación de un algoritmo de carga de las baterías. Este último se ajusta al procedimiento de carga especificado por el fabricante, estableciendo las tasas de carga en función de los escenarios en que la microrred se encuentre. El procedimiento de carga en las baterías es fundamental para garantizar las condiciones adecuadas de operación de las mismas, ya que toman en consideración los parámetros establecidos por el fabricante, como son: tasas de carga/descarga, tensión máxima de carga, temperaturas de operación, etc. / [CA] Dos dels aspectes crítics en l'operació d'una micro-xarxa són les estratègies de control i gestió de potència implementades, les quals són essencials per proporcionar el seu bon funcionament. L'aplicació adequada de dites estratègies permet compensar els desequilibris de potència causats per la discontinuïtat de la generació i demanda d'energia en les micro-xarxes. En aquest sentit, l'objectiu global de les nomenades estratègies de gestió és equilibrar adequadament el flux de potència en la micro-xarxa mitjançant l'aplicació de diferents algoritmes que permeten complir amb els criteris d'estabilitat, protecció, balanç de potència, transicions, sincronització amb la xarxa i gestió adequada de la micro-xarxa. En el cas de micro-xarxes de potència a petita escala i amb baix nombre de generadors i sistemes d'emmagatzematge distribuïts, les estratègies de control centralitzades ofereixen un alt nivell de flexibilitat per aconseguir funcionalitats avançades en la micro-xarxa i una adequada distribució de la potència entre els convertidors que la conformen. Aquesta tesi s'ha emmarcat al context d'algoritmes de gestió centralitzada de potència d'una micro-xarxa de generació distribuïda en mode de connexió a xarxa. Els algoritmes presentats es poden aplicar als convertidors de potència connectats al bus DC d'una micro-xarxa AC/DC hibrida o en una micro-xarxa de DC, on el despatx de potència és observat i gestionat per un controlador central. Aquest últim adquireix dades del sistema mitjançant una infraestructura de comunicacions i estima la potència que gestionarà cadascun dels convertidors de potència, sistemes d'emmagatzematge i càrregues en funcionament. En aquest estudi es mostren la validació experimental de les estratègies de gestió aplicades en la micro-xarxa des d'un enfocament dels convertidors de potència, de les bateries i les càrregues davant d'aquesta gestió. Es verifica l'estabilitat de la micro-xarxa exposant als convertidors a diferents escenaris de funcionament. Aquest escenaris poden ser fluctuants en la irradiació, la demanda, l'estat de càrrega de les bateries, els límits màxims d'exportació/importació de potència des de/cap a la micro-xarxa cap a/des de la xarxa principal i de la tarifa elèctrica. Addicionalment, es proposa un sistema d'emmagatzematge d'energia en bateries encarregats de mantindre l'equilibri de potència al bus DC de la micro-xarxa i que permet aprofitar les fonts de generació renovables presents en la micro-xarxa i maximitzar el temps de servei de les bateries mitjançant l'aplicació d'un algoritme de càrrega de bateries. Aquest últim s'ajusta al procediment de càrrega especificat pel fabricant, establint les taxes de càrrega en funció dels escenaris en que la micro-xarxa es trobe. El procediment de càrrega a les bateries es fonamental per garantir les condicions adequades d'operació de les mateixes, ja que prenen en consideració els paràmetres establerts pel fabricant, com ara són: taxes de càrrega/descàrrega, tensió màxima de càrrega, temperatures d'operació, etc. / [EN] Two critical aspects in microgrids operation are the control and power management strategies, which are essential for their efficient operation. The adequate application of these strategies allows compensating the power imbalance caused by the discontinuity in the energy generation or changes in the power demand of the microgrid. In this sense, the overall objective of these power management strategies is to keep the power balance between the generation and the demand in the microgrid through the application of different algorithms that fulfill the criteria of stability, protection, smooth transitions and synchronization with the main grid. In the case of small-scale microgrids with a low number of distributed generators and energy storage systems, the centralized control strategies offer a higher level of flexibility to achieve advanced features in the microgrid and for the suitable power sharing between the converters that compose it. This thesis has been focused on centralized power management algorithms of a microgrid working in grid connected mode. These algorithms can be applied to the power converters connected to the DC bus of both hybrid AC/DC and DC microgrids, where the power dispatch is controlled by a central controller which acquires system data through a communication infrastructure and sets the power to be managed by each of the converters under operation. In this thesis, the experimental validation of the power management strategies of the microgrid is presented, from the point of view of the behavior of the power converters, batteries and loads. It is provided with a realistic evaluation under different microgrid operation scenarios. These scenarios were sudden changes of the irradiation, load, state of charge, the maximum power to be exported/imported from/to the microgrid to/from the grid, and the electricity tariff. Additionally, it is proposed a battery energy storage system that keeps the power balance at the DC bus of the microgrid, taking advantage from the renewable energy sources and adjusting the battery energy storage through a suitable charging procedure specified by the manufacturer. The proposed procedure changes the charging parameters of the batteries depending on the microgrid states. Its goal is to extend the service time of batteries and to allow proper energy management in the system. / Salas Puente, RA. (2019). Gestión eficiente de los convertidores de potencia conectados al bus DC de una Microrred híbrida de generación distribuida [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/118658 / Compendio

In der Intralogistik führen technologieabhängig gekoppelte, drehzahlvariable Mehrmotorensysteme zu hohen Schwankungen im elektrischen Leistungsbedarf, der u.a. von der transportierten Gütermenge abhängt. Aufgrund der Überlappung der Lastanforderungen einzelner Verbraucher entstehen beträchtliche Lastmaxima, die das Versorgungsnetz belasten und eine Überdimensionierung der Infrastruktur erfordern. Ein räumlich ausgedehnter Gleichspannungsverbund in Kombination mit einem Energiespeichersystem sowie die Anpassung der Steuerung bieten Lösungen zur Verringerung der Netzanschlussleistung und des Energiebedarfs. Darüber hinaus ermöglichen solche Systeme eine effektive Rückgewinnung von potentieller und Bremsenergie. Am Beispiel eines Lagersystems mit Regalbediengeräten wird ermittelt, welche Reduktion des Netzleistungsbedarfs und Energieverbrauchs erreicht werden kann. Dabei werden ebenfalls die Auswirkungen auf die Durchsatzleistung des Systems untersucht. Dazu kommen Modelle des Bewegungsablaufes, der Komponenten der Antriebsstränge mit Abbildung von Mechanik, Getriebe, Motoren, Umrichter und der Speicher in einem Materialflussmodell zum Einsatz. Die Materialflusssimulationsumgebung wird dazu um die kontinuierlichen Modelle zu einem kombinierten Systemmodell erweitert und leistungsbegrenzende Steuerungsansätze im Zusammenwirken mit dem erweiterten Gleichspannungsverbund sowie den elektrischen Speichersystemen analysiert. Abschließend erfolgt die Ermittlung der Wirtschaftlichkeit der einzelnen Lösungen. Das Ergebnis ist ein Verfahren zur effizienten Betriebsweise von Intralogistiksystemen sowie eine Methode zur Dimensionierung eines räumlich ausgedehnten Gleichspannungsverbunds mit elektrischem Speicher. Zusammenfassend werden wirtschaftliche Maßnahmen identifiziert, die elektrische Lastmaxima reduzieren, die Schwankungen in der externen Energieversorgung verringern und die Energieeffizienz von Intralogistiksystemen verbessern. / In intralogistics, technologically linked, variable-speed multi-motor systems cause high fluctuations in electrical power demand due to variations in the amount of transported goods. These fluctuations often result in overlapping load demands by various consumers, which strain the supply network and require overdimensioning of infrastructure. To address this issue, a physically extended DC link, in combination with an energy storage system as well as adapted control, can reduce both grid power demand and energy consumption while allowing for the recovery of potential and braking energy. To evaluate the achievable reduction of grid power and energy demand, models were developed for individual components such as drive trains with motor, inverter, storage, axis coordination and material flow simulation with sequence control. An example of a warehouse system with storage and retrieval machines was used to determine the effects on throughput performance. To achieve this, the material flow simulation environment was extended to a combined system model, and performance-limiting control approaches were analyzed in interaction with the extended DC link and storage. Subsequently, economic feasibility of the individual solutions was determined. The result is a procedure for efficient operation of intralogistics systems and a methodology for dimensioning a physically extended DC link with electrical storage. The overall objective was to identify economic solutions that reduce electrical load peaks, balance external energy supply, and make intralogistics systems more energy-efficient. In conclusion, this study identifies economically viable solutions that can reduce electrical load peaks, balance external energy supply, and improve energy efficiency of intralogistics systems.

This term project deals with the problem of scheduling real-time tasks in overload conditions and techniques for lowering power consumption. Each of these parts features mechanisms and reasons for their using. There are also described specific algorithms, that are implemented, in operating system uC/OS-II, and compared in next phase of master's thesis.

Les circuits de récupération d'horloge et de données sont nécessaires au bon fonctionnement de plusieurs systèmes de communication sans fil. Les travaux effectués dans le cadre de cette thèse concernent le développement de ces circuits avec d'une part la réalisation, en technologie HCMOS9 0,13 μm de STMICROELECTRONICS, de circuits CDR analogiques à 1 et 54 Mbit/s, et d'autre part, la mise en œuvre de fonctions CDR numériques programmables à bas débit. Un circuit CDR fonctionnant à plus bas débit (1 Mbit/s) a été conçu dans le cadre de la gestion d'énergie d'un récepteur ULB impulsionnel non cohérent. Ces deux structures ont été réalisées à l'aide de PLL analogiques du 3ème ordre. Un comparateur de phase adapté aux impulsions issues du détecteur d'énergie a été proposé dans cette étude. Les circuits ont ensuite été dimensionnés dans le but d'obtenir de très bonnes performances en termes de jitter et de consommation. En particulier, les performances mesurées (sous pointes) du circuit CDR à 1 Mbit/s permettent d'envisager une gestion d'énergie efficace (réduction de plus de 97% de la consommation du récepteur). Dans le cadre d'une chaîne de télémesure avion vers sol, deux circuits CDR numériques ont également été réalisés durant cette thèse. Une PLL numérique du second degré a été implémentée en vue de fournir des données et une horloge synchrone de celles-ci afin de piloter une chaîne SOQPSK entièrement numérique. Un circuit ELGS a également mis au point pour fonctionner au sein d'un récepteur PCM/FM. / Clock and data recovery circuits are required in many wireless communication systems. This thesis is about development of such circuits with: firstly, the realization, in HCMOS9 0.13 μm of STMICROELECTRONICS technology, of 1 and 54 Mb/s analog CDR circuits, and secondly, the implementation of programmable digital circuits at low rates. In the aim of an impulse UWB transceiver dealing with video transmission, a CDR circuit at 54 Mb/s rate has been realized to provide clock signal synchronously with narrow pulses (their duration is about a few nanoseconds) from the energy detector. Another CDR circuit has been built at 1 Mb/s rate in a non-coherent IR- UWB receiver power management context. Both circuits have been implemented as 3rd order analog PLL. In this work, a phase comparator suitable for “RZ low duty cycle” data from the energy detector has been proposed. Circuits have been sized to obtain very good performances in terms of jitter and power consumption. Particularly, measured performances of the 1 Mb/s CDR circuit allow to plan an efficient power management (a decrease of more than 97% of the receiver total power consumption). In the context of a telemetry system from aircraft to ground, two digital CDR circuits have also been implemented. A second order digital PLL has been adopted in order to provide synchronous clock and data to an SOQPSK digital transmitter. Also, a digital ELGS circuit has been proposed to work in a PCM/FM receiver. For both CDR structures, the input signal rate is programmable and varies globally from 1 to 30 Mb/s.