A retarding potential analyzer (RPA) is an instrument that, when mounted on a satellite in low-Earth orbit, makes in-situ measurements of ion density, temperature and speed relative to the satellite frame. The instrument works by changing the voltage on one of a set of grids and measuring a corresponding current generated by ions flowing through the grid, generating a function of current vs. voltage called an I-V curve. Traditionally, the size and power requirements of retarding potential analyzers has limited their use to larger satellites. In this thesis, the electrical design and basic testing of a retarding potential analyzer for use on resource- limited cubesat platforms are described. The mechanical design of the retarding potential analyzer is first described, and the requirements of the electrical design are presented. The electrical requirements are based on both the characteristics of the ionosphereic flight environment, and on the size and power requirements typical of the small cubesat platforms for which the instrument is intended. The electrical hardware is then described in detail. The digital design is reviewed as well, including the instrument's operating modes, command and data structure, and timing scheme. Test data showing the basic functionality of the instrument are then presented. Bench tests validate the design by confirming its ability to control voltages and measure small currents. End-to-end tests were also performed in a vacuum chamber to mimic the ionospheric environment. These data are presented to show the ability of the RPA to meet or exceed its design specifications. / Master of Science

The bulk motion of the neutral gas at altitudes between about 200 and 600 km is an important factor in predicting the onset of plasma instabilities that are known to distort and/or disrupt high frequency radio communications. A ram wind sensor is a space science instrument that, when mounted on a satellite in low-Earth orbit, makes in-situ measurements of the component of the neutral gas velocity that lies along the orbit track of the satellite. The instrument works by changing the voltage on one of a set of grids and measuring a corresponding electron current generated by ions flowing through the grid stack and detected by the microchannel plate, generating a function of current vs. voltage called an I-V curve. Traditionally, the size and power requirements of ram wind sensors has limited their use to larger satellites. In this thesis, the electrical design and basic testing of a cubesat compatible RWS known as the ram energy distribution detector (REDD) are described. The mechanical design of the REDD sensor is first described, and the requirements of the electrical design are presented. The electrical requirements are based on both the characteristics of the ionosphereic flight environment, and on the size and power requirements typical of the small cubesat platforms for which the instrument is intended. The electrical hardware is then described in detail. The microcontroller design is reviewed as well, including the instrument's operating mode, and timing scheme. Test data showing the basic functionality of the instrument are then presented. Bench tests validate the design by confirming its ability to control voltages and measure small electron currents. End-to-end tests were also performed in a vacuum chamber to mimic the ionospheric environment. These data are presented to show the ability of the REDD sensor to meet or exceed its design specifications. / Master of Science

Electric vehicles are a key technology in the reduction of our carbon footprint and this has motivated significant research interest. The electrical traction motor is one of the main areas of research in attempts to further improve electric vehicle performance. The permanent magnet motor is the predominant device in this application because of its high specific torque. However, it has suffered from market speculation in the raw magnet materials which has generated efforts to develop electrical machines which have a high specific torque and do not contain rare earth materials. In the past the induction motor used to be the preferred motor for electric vehicles due to its low costs, low maintenance requirements, mature technology and robustness. The induction motor requires a higher specific torque to make it an alternative to permanent magnet machines. For this reason, this research had the primary aim of improving the specific torque of induction machines by undertaking a detailed review of the motor design because this process has conventionally focussed on the requirements for industrial applications. The first stage of the work presented in this thesis consisted of identifying the designs already in use for this purpose and the potential technologies applicable to the induction motor that could be transferred from other electric traction machines. A full review of the design process was also conducted in order to identify the key areas of the process with special reference to the electromagnetic design which used finite element techniques as the main modelling tool. New induction motor designs were developed which showed potential for improving the specific torque; two of these were selected for further refinement, prototyping and testing. Although these designs were modified to facilitate construction, some major difficulties were still encountered during the prototype rotor manufacture. The test results were used to validate the design process and to identify further improvements in the designs. The issues encountered with the rotor manufacture prototype however lead to some overheating during the experimental testing. Comments about the design experience gained during this research are summarized including suggestions for further research.

This diploma thesis deals with the issue of information transfer between the Department of Electrical Equipment Design and the Software Development Department of the control system of this machine. The diploma thesis focuses mainly on the elimination of the influence of the human factor while increasing the efficiency of this information transfer. System analysis examines the issues and investigates the reliability of information transfer. On the basis of the requirements resulting from the analysis, preventive measures and modifications of procedures in both departments have been proposed. Simultaneously, its own software applications have been developed to considerably simplify and accelerate the process, while meeting the requirements to eliminate problematic phenomena caused particularly by human factors. The resulting solution is verified according to the designated verification process and reassessed by own "SampleVUT" test project. Validation evaluates the effectiveness of the proposed solution.

This report presents the design and manufacturing process of a bionic signal messagebroker (BSMB), intended to allow communication between implanted electrodes andprosthetic legs designed by Ossur. The BSMB processes and analyses the data intorelevant information to control the bionic device. The intention is to carry out eventdetection in the BSMB, where events in the muscle signal are matched to the events ofthe gait cycle (toe-o, stance, swing).The whole system is designed to detect muscle contraction via sensors implantedin residual muscles and transmit the signals wireless to a control unit that activatesassociated functions of a prosthetic leg. Two users, one transtibial and one transfemoral,underwent surgery in order to get electrodes implantable into their residual leg muscles.They are among the rst users in the world to get this kind of implanted sensors.A prototype of the BSMB was manufactured. The process took more time thanexpected, mainly due to the fact that it was decided to use a ball grid array (BGA)microprocessor in order to save space. That meant more complicated routing and higherstandards for the manufacturing of the board. The results of the event detection indicatethat the data from the implanted electrodes can be used in order to get sucient controlover prosthetic legs. These are positive ndings for users of prosthetic legs and shouldincrease their security and quality of life.It is important to keep in mind when the results of this report are evaluated that allthe testing carried out were only done on one user each.

The electromechanical design and development of a sophisticated roller rig testing facility at the Railway Technologies Laboratory (RTL) of Virginia Polytechnic and State University (VT) is presented. The VT Roller Rig is intended for studying the complex dynamics and mechanics at the wheel-rail interface of railway vehicles in a controlled laboratory environment. Such measurements require excellent powering and driving architecture, high-performance motion control, accurate measurements, and relatively noise-free data acquisition systems. It is critical to accurately control the relative dynamics and positioning of rotating bodies to emulate field conditions. To measure the contact forces and moments, special care must be taken to ensure any noise, such as mechanical vibration, electrical crosstalk, and electromagnetic interference (EMI) are kept to a minimum. This document describes the steps towards design and development of all electromechanical subsystems of the VT Roller Rig, including the powertrain, power electronics, motion control systems, sensors, data acquisition units, safety and monitoring circuits, and general practices followed for satisfying the local and international codes of practice. The VT Roller Rig is comprised of a wheel and a roller in a vertical configuration that simulate the single-wheel/rail interaction in one-fourth scale. The roller is five times larger than the scaled wheel to keep the contact patch distortion that is inevitable with a roller rig to a minimum. This setup is driven by two independent AC servo motors that control the velocity of the wheel and roller using state-of-the-art motion control technologies. Six linear actuators allow for adjusting the simulated load, wheel angle of attack, rail cant, and lateral position of the wheel on the rail. All motion controls are performed using digital servo drives, manufactured by Kollmorgen, VA, USA. A number of sensors measure the contact patch parameters including force, torque, displacement, rotation, speed, acceleration, and contact patch geometry. A unified communication protocol between the actuators and sensors minimizes data conversion time, which allows for servo update rates of up to 48kHz. This provides an unmatched bandwidth for performing various dynamics, vibrations, and transient tests, as well as static steady-state conditions. The VT Roller Rig has been debugged and commissioned successfully. The hardware and software components are tested both individually and within the system. The VT Roller Rig can control the creepage within 0.3RPM of the commanded value, while actively controlling the relative position of the rotating bodies with an unprecedented level of accuracy, no more than 16nm of the target location. The contact force measurement dynamometers can dynamically capture the contact forces to within 13.6N accuracy, for up to 10kN. The instantaneous torque in each driveline can be measured with better than 6.1Nm resolution. The VT Roller Rig Motion Programming Interface (MPI) is highly flexible for both programmers and non-programmers. All common motion control algorithms in the servo motion industry have been successfully implemented on the Rig. The VT Roller Rig MPI accepts third party motion algorithms in C, C++, and any .Net language. It successfully communicates with other design and analytics software such as Matlab, Simulink, and LabVIEW for performing custom-designed routines. It also provides the infrastructure for linking the Rig's hardware with commercial multibody dynamics software such as Simpack, NUCARS, and Vampire, which is a milestone for hardware-in-the-loop testing of railroad systems. / Ph. D.

I detta examensarbete har en undersökning utförts på konsultföretaget ÅF, och deras arbetssätt inom dokumentation och kontrollanläggningar för att utreda om det fanns effektiviseringspotentialer. Undersökningen har i största del innefattat intervjuer med verksamma konsulter inom kontrollanläggningar och elmontage på transformatorstationer. Konsulterna arbetade som konstruktörer och tog fram ritningar främst till kontrollutrustningar. Resultatet från intervjuerna analyserades för att sedan dra slutsatser om effektiviseringsmöjligheter inom verksamheten. Olika kontor i verksamheten undersöktes och arbetssättet varierade på de olika kontoren. En skillnad var det CAD-program som användes och ett förslag var att använda samma program. Effektiviseringspotentialer fanns också genom att återanvända kretsscheman till viss del från föregående projekt. Ett annat förslag var därför att införa databaser där kretsscheman kan samlas in och delas mellan de olika kontoren. / In this thesis, a study has been carried out for the consulting company ÅF, and their work method within documentation and control facilities to investigate whether there were any potential for efficiency improvements. The investigation has largely involved interviews with operating consultants within the control facility on substations. The consultants worked as electrical designers and produced drawings mainly for control equipment. The results of the interviews were analyzed to draw conclusions about the efficiency potentials within the business. Different offices in the business were examined and the work approach varied between the offices. One difference was the CAD-software used and a suggestion was to use the same program. Efficiency improvement potentials were also by re-using electrical schematics to some extent from previous projects and another suggestion was to establish databases where electrical schematics can be gathered and shared between the different offices.

The induction machine with a squirrel cage is a workhorse of the industry. The main advantage of an induction machine is the low manufacturing price, simple and robust construction, low maintenance requirements. However, for high-speed applications, induction machine with a squirrel cage requires design modification due to the mechanical restrictions. The objective of this thesis is to show design process, methodology and assembly of the induction machine for high-speed applications. In this thesis, the rotor dimensioning data are presented. The results are demonstrated on the design of the 6 kW, 120 000 rpm solid rotor squirrel cage induction machine. This thesis also contains calculation and design of three different electrical machine topologies for a turbo circulator application. The electrical machines are designed with 6 kW output power at 120 000 rpm. The machines are estimated by using electromagnetic, thermal, and mechanical calculations. The drawbacks and advantages of each topology under study are described. For other high-speed applications, a comparative method helps in choosing the suitable electrical machine topology by examinations of discussed criteria. Rotor design effect on the electromagnetic performance of the induction machine is shown. Mechanical stresses are calculated with Finite Element Method analysis. Various assembly technologies to produce solid rotor with squirrel cage are discuss and compare. Describe approach enables high electromagnetic performance and durable construction of the high-speed induction machine. Work is confirmed by measurement on the manufactured prototype.