Antal nyregistrerade laddbara personbilarbilar ökar märkbart för varje år.Enligt en prognos kommer cirka 2.5 miljoner laddbara bilar vara i trafik iSverige år 2030. Detta motsvarar hälften av personbilsflottan idag.Ökningen av laddbara bilar sker framför allt i elområden SE3 och SE4.Detta påverkar hur transmissionsnätet påverkas i framtiden där mängdeneffekt som ska transmitteras från norr till södra landet ökar omomständigheterna i nätet är samma som idag. I detta examensarbeteuppskattades först effektökningen orsakade av elbilar år 2030 för denämnda elområdena. Sedan modellerades transmissionsnätet i SE3 ochSE4 för att undersöka hur denna effektökning påverkar transmissionsnätetoch dess förluster.Resultatet visade att effektökningen kommer att belastatransmissionsnätet hårdare än idag. För effektöverföring mellan SE2 ochSE3 passeras den maximala överföringskapaciteten redan idag för vissatimmar av året. Resultatet i denna rapport visar att sådana timmar kommeratt vara betydligt fler för år 2030 och förlusterna kommer att öka. Detvisade sig att för SE4 kommer den maximala överföringskapacitetenräcka för år 2030. / The number of newly registered rechargeable passenger cars in Swedenincreases noticeably every year. According to a forecast, there will bearound 2.5 million cars in traffic in 2030. This corresponds to half of thepassenger car fleet today.The increase in rechargeable cars takes place above all in electricity areas:SE3 and SE4. This affects how the Swedish national grid is affected in thefuture, where the amount of power to be transmitted from the north to thesouth of the country increases if the conditions in the grid are the same astoday. In this bachelor thesis, the power increase caused by electric carsin 2030 was first estimated for the mentioned electricity areas. Then thepower transmission grid was modeled for SE3 and SE4 to investigate howelectric cars will affect the national grid and its losses.The result showed that the power increase will load the national grid moreheavily than today. For power transmission between SE2 and SE3, themaximum net transfer capacity is already exceeded for certain hours ofthe year. The result in this report shows that such hours will besignificantly more for the year 2030 and the losses in the grid willincrease. It turned out that for SE4, the maximum transmission capacitywill be sufficient for the year 2030.

In the present thesis, we propose and investigate a new approach to diagnose the effects of the various degradation mechanisms, including thermal degradation at hot spots, winding deformations due to the mechanical forces from short circuit currents, partial discharges due to local electric field surges, and increased moisture levels in the cellulose insulation due to decomposition, that affect electric power transformers during their normal operation in an electric power grid. Although the proposed diagnostics method can in principle be used to detect various degradation mechanisms mentioned above, we focus in the present thesis on mechanical deformations of transformer winding structures. Such mechanical deformations are most often caused by mechanical forces from short circuit currents, but they may also be caused by initial manufacturing errors and inconsistencies not detected by the power transformers’ suppliers quality assurance processes. We model a transformer winding surrounded by the transformer-tank wall and the magnetic core as a two-dimensional parallel plate waveguide or as a three-dimensional coaxial waveguide, where one metallic boundary (plate or cylinder) represents the wall of the transformer tank and the other metallic boundary (plate or cylinder) represents the iron core that conducts the magnetic flux. In between there is a set of parallel or coaxial conductors representing the winding segments. The new principle proposed in the present thesis is to insert a number of antennas into a transformer tank to radiate and measure microwave fields interacting with metallic structures and insulation. The responses from the emitted microwave radiation are expected to be sensitive to material properties that reflect the changes caused by any harmful deterioration processes mentioned above. Specifically, we investigate the mechanical deformations of transformer winding structures by determining the locations of the individual winding segments or turns, using measurements of the scattered fields at both ends of the winding structure. We solve the propagation problem using conventional waveguide theory, including mode-matching and cascading techniques. The inverse problem is solved using modified steepest-descent optimization methods. The optimization model is tested by comparing our calculated scattering data with synthetic measurement data generated by the commercial program HFSS. A good agreement is obtained between the calculated and measured positions of winding segments for a number of studied cases, which indicates that the diagnostics method proposed in the present thesis couldbe potentially useful as a basis for the design of a future commercial on-line winding monitoring device. However, further development of the theoretical analysis of a number of typical winding deformations, improvements of the optimization algorithms and a practical study with measurements on an actual power transformer structure are all needed to make an attempt to design a commercial winding monitoring device feasible. / <p>QC 20131007</p>

The purpose of the thesis was to evaluate the robustness of the Hybrid A* algorithm in regards to the levels of dynamic vehicle modeling, vehicle parameters and driving velocity. The original scope of the thesis project was to alter vehicle and tire models but this was discovered to be out of the time limits of the thesis project. The new scope was to alter the parameters with close connection to the vehicle dynamics, such as tire friction, vehicle mass and driving velocity. The thesis project was performed in collaboration with Syntronic and their internal project Autodrive.  Due to the complexity of the system, tests were first performed to evaluate if the path planner and path following were deterministic. Variation of tire friction, vehicle mass, reference velocity and maximum steering was then performed during three different driving missions designed to simulate different complexity levels of realistic driving scenarios. The dependence of the varied vehicle parameters on the deterministic behaviour was also examined. Lastly, the impact of altering parameters used for smoothing of the Hybrid A* solution and parameters of the controller were explored and analysed. The position of the vehicle, the velocity profile, slip angles and angular acceleration were used in order to draw conclusions regarding the performance of Hybrid A*, the motion control and the limitations of vehicle and tire models.  The results showed that the implementation used of Hybrid A* is deterministic but fail to produce a consistent route when faced with obstacles and re-planning due to the vehicle control not being deterministic. Variation in vehicle mass and reference velocity as well as the aggressiveness of the course were concluded to impact the determinism of the path following. The best values for the smoothing parameters are dependent on the desired vehicle behaviour, but can be used to reduce the difference between the planned and followed path.  The Hybrid A* planner was concluded to be robust in regards to variations in vehicle mass, tire friction and maximum steering angles but very sensitive to a change in velocity. The slip angles were generally small, but the kinematic single-track model theoretically only hold when the slip angles are zero. The results did, however, indicate that the implementation of the Hybrid A* algorithm was able to produce a drivable and realistic path for all cases except the most extreme parameter choices. For larger velocities and unrealistically low tire friction, the dynamic single-track model is more suitable.  The choice of vehicle model is not critical except when using high driving velocities. It is important to have knowledge of the desired driving velocity when choosing a dynamic model, but the solution of the implemented path planner and path following is otherwise robust enough to handle a less advanced model. The current implementation of the Hybrid A* algorithm, using the kinematic single-track model, can therefore be concluded to be sufficient in planning a realistic path for a simulated autonomous vehicle for low driving velocities, while a more advanced model is needed when increasing the driving velocity.

Integrated Circuit (IC) designers have always faced the problem of small deviations in parameters of their designs in manufactured ICs. This variation due to the manufacturing process (Process Variation) in device parameters from their nominal values result in altered performance and can cause integrated circuits to be malfunctioning. With Moore’s Law going strong, the device dimensions of integrated circuits continue to shrink. This is exacerbating the issue with deviations from nominal design values. Several methods and techniques are employed to reduce the impact of this type of undesirable variation. This thesis explores a method of measuring the variation inside an IC. An accurate measurement of the variation has the potential to enable compensation techniques, tuning performance to desirable levels or even turning a malfunctioning ICs into functional ones. This thesis proposes a method to obtain an accurate digital representation of the variation, a Process Sensor. The proposed sensor is capable of detecting the variation in P-type Metal Oxide Semiconductor (PMOS) and N-type Metal Oxide Semiconductor (NMOS) devices independently. In addition, a theoretical method to disentangle the temperature dependence from the variation measurement is explored. And conversely via the same method, temperature dependence can be increased, effectively turning the process sensing circuitry into a temperature sensing circuitry.

In Sweden, the change from manual meter reading at irregular intervals, to automatic remote meter reading at predefined instants was completed in July 2009. This change is ongoing or largely completed in a number of other European countries as well. Several methods for communication between the meter and the network operator are in use. In Sweden power-line communication is used for communication with about half of the meters. The frequency range between 9 and 95 kHz contains, in addition to communication signals, conducted emission from end-user equipment connected to the power grid. Electronic components in end-user equipment can also in other ways affect the characteristic of the power lines as a communication media.The aim of this thesis is to give an overview of how power line communication in the frequency range 9 to 95 kHz can interact with modern energy saving end-user equipment. Potential problems concerning this interaction have been identified.Results presented in this thesis are based on a large number of measurements of voltage and current distortions due to connected loads and due to power line communication.A total of five different ways of interaction between power-line communication and end-user equipment are identified in this thesis. As a spin-off from this work, also new aspects of the interaction between end-user equipment have been identified.

I detta projekt har målet varit att utveckla en elektronikenhet som möjliggör mätning av ström och spänning i tre faser. En viktig motivation för detta arbete äratt hantera utmaningarna med varierande nätkvalitet vid export av trefasmaskinerglobalt. Genom att övervaka ström och spänning kan användare få information omeventuella förändringar för att skydda maskinerna. Resultaten av detta arbete innefattar en jämförelse av olika sensorer, vilket ledde tillvalet av EVAL_ADE9430ARSDZ-kortet för att säkerställa att alla specifikationeruppfylldes. Efter att kortet hade programmerats genomgick det olika tester för attsäkerställa att alla specificerade kriterier uppfylldes. Resultaten visade en avvikelsemed endast cirka 0,163% för spänningsmätningar och 5,11% för strömmätningar. Sammanfattningsvis har detta arbete möjliggjort utvecklingen av en enhet som kanvara värdefull för tillverkare av mobil trefasansluten utrustning och kan bidra till attsäkerställa maskiners prestanda under varierande nätvillkor. Det finns dock utrymme för vidare utveckling och förbättringar av mätdatainsamlingen för att genereramer omfattande och detaljerade resultat. / In this project, the goal has been to develop an electronic unit enabling the measurement of current and voltage in three phases. An essential motivation for thiswork is to address the challenges posed by varying power quality when exportingthree-phase machinery globally. Users can be informed of any changes to protect themachinery by monitoring current and voltage. The results of this work include a comparison of different development sensors,leading to the selection of the EVAL_ADE9430ARSDZ board to ensure that allspecifications were met. After programming, the board underwent various tests toverify compliance with all specified criteria. The results indicated a deviation ofonly approximately 0.163% for voltage measurements and 5.11% for current measurements. In summary, this work has facilitated the development of a device that can be valuable for manufacturers of mobile three-phase equipment, contributing to ensuringmachine performance under varying power conditions. However, there is room forfurther development and improvements in data collection to generate more comprehensive and detailed results.

Wireless sensor networks are emerging from the mobile ad hoc network concept and as such they share many similarities. However, it is not the similarities that differentiates sensor networks from their ad hoc counterparts, it is the differences. One of the most important difference is that they should operate unattended for long periods of time. This is especially important since they usually rely on a finite energy source to function. To get this into a perspective, a sensor network constitutes of a sensor field where a number of sensor nodes are deployed. The sensor nodes relay the gathered information to a base station from which the data are forwarded either through a network or directly to the enduser. The communication between sensor nodes are conducted in an ad hoc manner, which means that paths toward the base station are dynamically constructed based on current network conditions. The network conditions changes and examples of this includes node failure, deactivated nodes, variations in the radio channel characteristics, etc. As mentioned above, the sensor nodes are energy constrained and one of the more important design criteria is the life time of a sensor node or network. To be able to evaluate this criteria an energy dissipation model is needed. Most of the energy dissipation models developed for wireless sensor networks are not based on the basic sensor node architecture and as such they where not accurate enough for our needs. Thus, an energy dissipation model was developed. This model utilises the basic sensor node architecture to obtain the operation states available and their corresponding state transitions. Communication is the most energy consuming task a sensor node can undertake. As such, the contributed energy dissipation model is used to evaluate this aspect of the proposed controlled flooding protocols. Generally, the controlled flooding protocols tries to minimise the number of forwarding nodes and by doing this they lower the energy consumed in the network. Along with this, the communication overhead of a protocol also needs to be taken into account. Our idea is to utilise the received signal strength directly to make forwarding decisions based on a cost function. This idea has a number of key features, which are: no additional overhead in the message, no neighbour knowledge and no location information are needed. The results from the proposed flooding protocols are promising as they have a lower number of forwarding nodes and a longer lifetime than the others. / <p>Report code: LIU-TEK-LIC-2007:43.</p>

Abstract  Eskilstuna Strängnäs Energi och Miljö is an energy company that provides electricity to its customers in the Eskilstuna and Strängnäs region. The company is currently facing stability problems in its electrical grid caused by a change in load patterns and increased implementation of renewable energy sources. Research has shown that batteries can provide flexibility which allows stabilisation on these evolving grids. The purpose of this thesis is to evaluate how a grid connected battery and its inverter can provide stability in a distribution grid where the production of electricity suddenly changes. To get the results that were requested, a simscape-MATLAB model was used, which follows the IEEE requirements for inverter-based resources. The results from the simulation were presented in multiple graphs and revealed the capability of a battery to restore a balance between production and consumption of electricity very quickly. The results also showed that a grid forming inverter provides a faster response from the battery, allowing it to stabilize the grid faster than a grid following inverter. The results showed that the grid forming inverter is more suitable for the future electrical grid that is getting weaker than the grid following inverter

This degree project is done in collaboration with Vinnergi AB at their officein Halmstad. The aim for this project is to deliver a proposal for a new charging station in Trelleborg with focus on technology implementation. With an increase in electrification in the transport sector comes the need to construct more charging stations in order to keep up with the increased demand for charging points for electric vehicles. This report will cover research for existing chargers at the same location in order to determine the current usage of those chargers, the amount of chargers that the nearby electrical grid can handle as well as a power quality study for the existing electrical grid. To reach the specified goals, simulations of the actual electrical grid were conducted along with several calculations and technology considerations that were partly based on the simulations. This research came up with a new proposal for a charging station with two charging posts for fast charging with a charging capability of between 175 kW and 350 kW. Cables, breakers and a grounding system for the chargerswere evaluated and chosen along with a fundamental budget for the whole project. This proposed charging station will extend the charging capabilities in the area and be a part of keeping up with the increased demand for fast andreliable charging in Trelleborg.

Mikrovågsuppvärmning är en viktig process som används i många industriella tillämpningar. Användningen av mikrovågsuppvärmning inom industri är dock inte lika utbredd som den har potential till att vara på grund av orsaker som säkerhet, strålning och brist på kunskap. Arbetets mål är att få ökad förståelse för hur materialegenskaper som permittivitet, termisk ledningsförmåga och elektrisk ledningsförmåga påverkar upphettning i mikrovågsugn. För att åstadkomma detta utförs simuleringar samt experiment på grafit som undersöks under mikrovågsuppvärmning i kiln anpassad för mikrovågsugn. Resultaten jämförs med liknande simulationer av det dielektriska materialet regolit. Händelsen simuleras först i COMSOL Multiphysics varefter korresponderande laboration utförs i verkligheten. För att åstadkomma fungerande simulation i COMSOL kalibreras den med hjälp av en tidigare utförd simulation av kiln i mikrovågsugn samt med COMSOLs egna Microwave Heating-tutorial. Under arbetets gång läggs mycket energi på att optimera simuleringen utefter diverse problem, exempelvis att simulationen är väldigt krävande. Slutligen uppnås fungerande simuleringar som relaterade väl till det riktiga experimentet.