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The need to make more efficient use of energy resources by improved methods of control, the deferment of expensive pipework reinforcement or replacement and the requirement to accommodate different loading patterns on sections of the gas network have made the requirement for effective feedback control essential. Gas distribution systems are large and complex and a major problem in applying conventional feedback techniques is the cost and reliability of transmitting the data necessary for automatic control. In order to overcome these difficulties, state estimation techniques have been investigated as a means of providing information about a distribution system from a minimum number of measurement points. The theoretical background to the study is reviewed including the modelling technique and the results of experimental work which has been performed on a distribution network in order to verify the techniques developed are presented. The results show that state estimation techniques have considerable potential for this type of application.

Reduction of aircraft loads, arising as a result of manoeuvre commands or atmospheric turbulence, by means of active control is an important problem in flight control. A variety of methods of designing appropriate control systems to achieve such reduction are available, but not every method is effective. A feature of this research work is the use of an eigenvalue/eigenvector assignment method using full state variable feedback, to design aircraft load alleviation control systems.

In response to the global concerns towards oil scarcity and climate change, the automotive industry is currently focusing on improving fuel economy and reducing exhaust emissions. Modern downsized gasoline engines that come with a package that includes a boosting system, variable valve train and direct fuel injection system is effective for fuel economy improvement and emission reduction. However, the knocking issue becomes severe at high load operations as a result of the high intake boosting pressure. In regard to the part load conditions, the gas exchange process requires extra work to draw in air into the cylinder due to a lower amount of pressure in the intake manifold caused by the restriction of the throttle plate. The Miller cycle is regarded as a potential strategy of knock control for downsized gasoline engines. Extensive works have sought to examine the performance improvement via the Miller cycle, yet only limited research has been conducted on the manner in which it can influence knock suppression. The focus of this thesis is to investigate early and late intake valve closing timings in terms of how they affect the compression process, the ability to suppress engine knock and meet the power output required at high loads for spark-ignited gasoline engines. Apart from that, this research also demonstrates the Miller cycle potential by utilising fully variable valve timing in controlling the load at the part load condition without using a throttle. The early intake valve closing with different valve lifts was tested in order to investigate the impact during the gas exchange process, particularly the pumping losses and the potential to improve fuel economy. This study includes both experimental and simulation studies. A Lotus single-cylinder research engine referred to as SCORE was mainly used for the experimental component of the study. The simulation work was conducted using a one-dimensional spark ignition engine model built in the Ricardo WAVE software for naturally-aspirated and downsized engines. The engine model values are validated against the experimental values from the Lotus SCORE and Lotus SABRE engines. The combustion model with a reduced kinetics mechanism was validated using a Rover K-series engine. A broad matrix of the engine operations has been investigated combining a variety of engine speeds and engine loads. The Miller cycle effects on knock suppression in a downsized engine environment have been investigated in three parts, namely the Miller cycle at different speed-load, knock suppression with extreme Miller cycle, and knock analysis with combustion kinetics. Through the works, the Miller cycle has demonstrated its capability to suppress engine knocking in a more efficient manner as opposed to the standard engine operation. This is contributed by the fact that early and late intake valve closings could affect the end gas condition at the end of the compression stroke, thus making it possible to suppress the engine knocking. The experimental study for controlling load without using throttle under the naturally-aspirated condition found that the Miller cycle with an early intake calve closing strategy able to improve fuel consumption by reducing pumping losses. The downsized engine condition, which has been evaluated via modelling work, also showed an improved performance trend using the unthrottled Miller cycle strategy. The open cycle and close cycle efficiencies have improved through the Miller cycle implementation. The contribution of this work is made in order to establish the comparison of the Miller cycle strategy in suppressing knocking between the early intake valve closing and late intake valve closing under a boosted environment. For the part load condition of the downsized engine, the research contributes to the existing body of knowledge by comparing the throttle-less Miller cycle and the standard throttled operation as a load control strategy.

This thesis investigates the load control of a marine current energy converter using a vertical axis turbine mounted on a permanent magnet synchronous generator. The purpose of this thesis is to show the work done in the so far relatively uncharted territory of control systems for hydro kinetic energy conversion. The work is in its early stage and is meant to serve as a guide forfuture development of the control system. An experimental power station has been deployed and the first results are presented. A comparison between three load control methods has been made; a fixedAC load, a fixed pulse width modulated DC load and a DC bus voltage control of a DC load. Experimental results show that the DC bus voltage control reduces the variation of rotational speed with a factor of 3.5. For all three cases, the tip speed ratio of the turbine can be kept close to the expected optimal tip speed ratio. However, for all three cases the average extracted power was significantly lower than the average power available in the turbine times the estimated maximum power coefficient. A maximum power point tracking system, with or without water velocity measurement, should increase the average extracted power. A simulation model has been validated using experimental data. The simulated system consists of the electrical system and a hydrodynamic vortex model for the turbine. Experiments of no load operation were conducted to calibrate the drag losses of the turbine. Simulations were able to predict the behaviour in a step response for a change in tip speed ratio when the turbine was operated close to optimal tip speed ratio. The start position of the turbine was varied in the simulation to view the influence on the step response from a changed turbine position relative to the direction of the water flow. / <p>Funders: J Gust Richert, Bixia Miljöfond</p>

Load control design is one of the major cornerstones of radio resource management in today's UMTS networks. A WCDMA cell's ability to utilize available spectrum efficiently, maintain system stability and deliver minimum quality of service (QoS) requirements to in-cell users builds on the algorithms employed to manage the load. Admission control (AC) and congestion control (CC) are the two foremost techniques used for regulating the load, and differing environments will place varying requirements on the AC and CC schemes to optimize the QoS for the entire radio network. This thesis studies a real-life situation where cells are put under strenuous conditions, investigates the degrading effects a high-speed train has on the cell's ability to maintain acceptable levels of QoS, and proposes methods for mitigating these effects. The scenario is studied with regard to voice traffic where the limiting radio resource is downlink power. CC schemes that take levels of fairness into account between on-board train users and outdoor users are proposed and evaluated through simulation. Methods to anticipatorily adapt radio resource management (RRM) in a cell to prepare for a train is proposed and evaluated through simulation. A method to detect a high-speed train in a cell, and the users on it, is outlined and motivated but not simulated. Simulation results are promising but not conclusive. The suggested CC schemes show a surprising tendency towards an increase in congestion avoidance performance. Proactive RRM shows a significant increase in QoS for on-board users. No negative effects to users in the macro environment is noticed, with regard to the studied metrics.

Muitos são os objetivos para o controle de carga no comércio exterior. Organismos Internacionais estabelecem programas voltados à segurança física das instalações e navios. Acordos bilaterais entre o Brasil e os Estados Unidos da América estabelecem programas com a ênfase em segurança. Os objetivos do Estado brasileiro representado pela Secretaria da Receita Federal estão voltados primeiramente à regulamentação do mercado com a nacionalização das cargas e seu devido recolhimento de impostos. Para isto utiliza sistemas de alcance nacional como SISCOMEX Importação, Exportação e Trânsito Aduaneiro, para controlar o fluxo das cargas no comércio exterior. Estes sistemas possuem o enfoque nas mercadorias já presentes no território nacional. Outro objetivo é a necessidade de facilitação da burocracia e também a busca por segurança. A preocupação com a segurança deve estar presente nos sistemas informatizados, e aí se adota a certificação digital como forma segura de transmissão dos dados, como na operação física da carga. A operação física, no modal marítimo na importação, inclui a informação do Transportador sobre seu manifesto, a informação do Operador Portuário sobre a descarga efetuada, a informação do Recinto Alfandegado que irá armazenar esta carga. Dois sistemas operam na unidade local da Alfândega do Porto de Santos, a Supervia Eletrônica de Dados, com os Transportadores Marítimos e Operadores e a Declaração de Transferência Eletrônica, com os Operadores Portuários e Recintos. A integração destes sistemas interage dois universos da logística de transporte, o marítimo e o terrestre com a distribuição e armazenagem da carga, tudo sob supervisão das autoridades Portuária e Aduaneira. Mostra-se que esta integração diminui burocracia, aumenta controles, valida dados com benefício a toda comunidade aduaneira. Fornece informações mais seguras para a Autoridade Portuária facilitando o faturamento de seu contrato de privatização. Favorece as interações dos Armadores com a Alfândega, pois possibilita via internet tanto solicitações quanto autorizações. Facilita a autorização de transferência de carga para os Recintos diminuindo sua digitação, garante unicidade dos dados da carga em todos intervenientes permitindo sua alteração no banco de dados somente após o procedimento legal e permite também o fechamento do manifesto, conciliando as cargas manifestadas com as descarregadas e também com o despacho aduaneiro a que foi submetida tal mercadoria. / There are many objectives for the load control in the foreign commerce. World Customs Organization establishes programs directed to the physical security of the installations and ships. Bilateral agreements between Brazil and the United States of America establish programs with the emphasis in security. The objectives of the Brazilian State represented by its Custom are focus first in the regulation of the market with the nationalization of loads and its collect taxes. For this it uses systems of national reach as SISCOMEX Importation, Exportation and Customs Transit, to control the flow of loads in the foreign commerce. These systems possess the approach on the merchandise already in the national territory. Another objective is the necessity of facilitation of the bureaucracy and also the search for security. The concern with the security must be present also in the computers systems, where it adopts the digital certification as safe form of transmission of the data, as in the physical operation of the load. The physical operation, in the modal marine in the importation, includes the information of the transporter on its manifesto, the information of the Port Operator on the effected discharge, the information of the Bonded Enclosure that will go to store this load. Two systems operate in the local unit of the Customs of the Santos\' Port, the Electronic Supervia of Data, with the maritime transporters and operators and the Declaration of Electronic Transference, with the Port Operators and Enclosures. The integration of these systems interacts two universes of the logistic of transport, the marine and terrestrial with the distribution and storage of the load, everything under supervision of the authorities of the port and customs. One reveals that this integration diminishes bureaucracy, increases controls, and validates data with benefit for all the customs community. Supplies safer information to the port authority, facilitating the invoicing of its contract of privatization. It favors the interactions of the Ship owners with Customs; therefore it makes possible interaction in such a way thru Internet as much the requests as the authorizations. It facilitates the authorization of the load transference for the Enclosures diminishing its typing, guarantees unicity of the data of the load allowing its alteration in the data base only after the legal procedure and also allows to the closing of the manifesto, conciliating loads revealed with unloaded and also with the customs forwarding the one that was submitted such merchandise.

Muitos são os objetivos para o controle de carga no comércio exterior. Organismos Internacionais estabelecem programas voltados à segurança física das instalações e navios. Acordos bilaterais entre o Brasil e os Estados Unidos da América estabelecem programas com a ênfase em segurança. Os objetivos do Estado brasileiro representado pela Secretaria da Receita Federal estão voltados primeiramente à regulamentação do mercado com a nacionalização das cargas e seu devido recolhimento de impostos. Para isto utiliza sistemas de alcance nacional como SISCOMEX Importação, Exportação e Trânsito Aduaneiro, para controlar o fluxo das cargas no comércio exterior. Estes sistemas possuem o enfoque nas mercadorias já presentes no território nacional. Outro objetivo é a necessidade de facilitação da burocracia e também a busca por segurança. A preocupação com a segurança deve estar presente nos sistemas informatizados, e aí se adota a certificação digital como forma segura de transmissão dos dados, como na operação física da carga. A operação física, no modal marítimo na importação, inclui a informação do Transportador sobre seu manifesto, a informação do Operador Portuário sobre a descarga efetuada, a informação do Recinto Alfandegado que irá armazenar esta carga. Dois sistemas operam na unidade local da Alfândega do Porto de Santos, a Supervia Eletrônica de Dados, com os Transportadores Marítimos e Operadores e a Declaração de Transferência Eletrônica, com os Operadores Portuários e Recintos. A integração destes sistemas interage dois universos da logística de transporte, o marítimo e o terrestre com a distribuição e armazenagem da carga, tudo sob supervisão das autoridades Portuária e Aduaneira. Mostra-se que esta integração diminui burocracia, aumenta controles, valida dados com benefício a toda comunidade aduaneira. Fornece informações mais seguras para a Autoridade Portuária facilitando o faturamento de seu contrato de privatização. Favorece as interações dos Armadores com a Alfândega, pois possibilita via internet tanto solicitações quanto autorizações. Facilita a autorização de transferência de carga para os Recintos diminuindo sua digitação, garante unicidade dos dados da carga em todos intervenientes permitindo sua alteração no banco de dados somente após o procedimento legal e permite também o fechamento do manifesto, conciliando as cargas manifestadas com as descarregadas e também com o despacho aduaneiro a que foi submetida tal mercadoria. / There are many objectives for the load control in the foreign commerce. World Customs Organization establishes programs directed to the physical security of the installations and ships. Bilateral agreements between Brazil and the United States of America establish programs with the emphasis in security. The objectives of the Brazilian State represented by its Custom are focus first in the regulation of the market with the nationalization of loads and its collect taxes. For this it uses systems of national reach as SISCOMEX Importation, Exportation and Customs Transit, to control the flow of loads in the foreign commerce. These systems possess the approach on the merchandise already in the national territory. Another objective is the necessity of facilitation of the bureaucracy and also the search for security. The concern with the security must be present also in the computers systems, where it adopts the digital certification as safe form of transmission of the data, as in the physical operation of the load. The physical operation, in the modal marine in the importation, includes the information of the transporter on its manifesto, the information of the Port Operator on the effected discharge, the information of the Bonded Enclosure that will go to store this load. Two systems operate in the local unit of the Customs of the Santos\' Port, the Electronic Supervia of Data, with the maritime transporters and operators and the Declaration of Electronic Transference, with the Port Operators and Enclosures. The integration of these systems interacts two universes of the logistic of transport, the marine and terrestrial with the distribution and storage of the load, everything under supervision of the authorities of the port and customs. One reveals that this integration diminishes bureaucracy, increases controls, and validates data with benefit for all the customs community. Supplies safer information to the port authority, facilitating the invoicing of its contract of privatization. It favors the interactions of the Ship owners with Customs; therefore it makes possible interaction in such a way thru Internet as much the requests as the authorizations. It facilitates the authorization of the load transference for the Enclosures diminishing its typing, guarantees unicity of the data of the load allowing its alteration in the data base only after the legal procedure and also allows to the closing of the manifesto, conciliating loads revealed with unloaded and also with the customs forwarding the one that was submitted such merchandise.

<p>This thesis involves the development of a system for control of a marine current energy conversion system. The control system is developed on the principles of load control, i.e. it aims to control the rotational speed of the turbine by controlling the power extracted from the generator. The system operates by feedback of the generator DC-voltage and current as well as the speed of the water current passing through the turbine. An IGBT-transistor controlled by an AVR-microcontroller executes control of the generator and hence the turbine. A digitally implemented PID-controller serves as the fundamental automatic control regime. The control system can be operated from a PC-application connected to the microcontroller through a serial wire connection. From the graphical user interface ofthe PC-application the system operator can set the system control parameters and monitor the state of the generator and turbine. The control system can be set to keep the turbine operating at a desired tip speed ratio, rotational speed or generator voltage. Further, for purposes of indoor testing of the control system a separate system, a motor control system, was developed as a part of this thesis work. The purpose of the motor control system is to enable simulating the behavior of a turbine with a motor driving the generator instead of an actual turbine. The motor control system operates by control of an ACS800 variable frequency drive that is connected to the motor. The motor control system allows its operator to feed in data describing the variations in water speed over time as well as data describing how the simulated turbine's power coefficient depends on its tip speed ratio. From this data the motor control system continuously calculates the torque that should be put on the generator axis by the motor. Results from test runs of the system show that the performance of the system is good. The system responds quickly to changes in the control parameters. Also the system manages to keep the specified control parameter quite well even during rapid changes in the water speed.</p>

This thesis involves the development of a system for control of a marine current energy conversion system. The control system is developed on the principles of load control, i.e. it aims to control the rotational speed of the turbine by controlling the power extracted from the generator. The system operates by feedback of the generator DC-voltage and current as well as the speed of the water current passing through the turbine. An IGBT-transistor controlled by an AVR-microcontroller executes control of the generator and hence the turbine. A digitally implemented PID-controller serves as the fundamental automatic control regime. The control system can be operated from a PC-application connected to the microcontroller through a serial wire connection. From the graphical user interface ofthe PC-application the system operator can set the system control parameters and monitor the state of the generator and turbine. The control system can be set to keep the turbine operating at a desired tip speed ratio, rotational speed or generator voltage. Further, for purposes of indoor testing of the control system a separate system, a motor control system, was developed as a part of this thesis work. The purpose of the motor control system is to enable simulating the behavior of a turbine with a motor driving the generator instead of an actual turbine. The motor control system operates by control of an ACS800 variable frequency drive that is connected to the motor. The motor control system allows its operator to feed in data describing the variations in water speed over time as well as data describing how the simulated turbine's power coefficient depends on its tip speed ratio. From this data the motor control system continuously calculates the torque that should be put on the generator axis by the motor. Results from test runs of the system show that the performance of the system is good. The system responds quickly to changes in the control parameters. Also the system manages to keep the specified control parameter quite well even during rapid changes in the water speed.