In this project a humidity sensor will be integrated to measure humidity. There are several different methods for integrating a humidity sensor but for this project two models will be used to integrate the sensor and compare with the theory. The construction of the two models are in KiCad and then it will be ordered as PCBs. The voltage of the output of the integrated circuits will be measured and then converted to humidity by using the simulated capacitance value of the sensor. This will be compared with the theory to see which of these models that are appropriate for the selected sensor. To convert the analog signals into digital values, the objective was to program it in the microprocessor. All algorithms are implemented to the hardware in C. / I det här projektet kommer en luftfuktighetssensor att integreras för att mäta luftfuktighet. Det finns flertalet olika metoder för att integrera en luftfuktighetssensor men det som kommer att användas i detta projekt är två olika modeller att implementera och jämföra med teorin. Konstruktionen av de två olika modellerna görs i KiCad för att sedan beställas som kretskort. Spänningen på utgången på de integrerade kretsarna ska mätas för att sedan omvandlas till luftfuktighet med hjälp av de simulerade kapacitansvärdena på sensorn. Detta kommer att jämföras med teorin för att se om dessa modeller är lämpliga för just den valda sensorn. För att omvandla den analoga utsignalen till digitala värden var målet att programmera det i mikroprocessorn. Alla algoritmer till hårdvaran har implementerats i C.

Analog-to-Digital converters, ADCs, introduces the possibility of performing digital computation on real world analog signals by being the interface between thetwo domains. The demands on the performance of the ADC is steadily increasing, which also comes with an increased difficulty of actually being able to guarantee the functionality of the device. Therefore, the art of estimating the characteristics of the ADC has flourished over the years where researchers has sugested ways of performing different test procedures to arrive at the most accurate method suited for a specific application. In this thesis, a measurement device containing an ADC is the subject of investigation. Some of the static characteristics of the ADC were estimated by isolating the ADC in the circuit and putting it through a set of tests developed in a lab environment and analyzing the resulting data offline. By then also carrying out measurements of the whole system, the amount of input referred noise added by the ADC could be estimated.

Radar has emerged as an important sensor for scenario perception in automated driving and surveillance systems. The exponential increase of radar units in traffic and their operating frequency limitations have given rise to the problem of mutual interference. Radar's performance degrades in the presence of interference, which can result in false alarms and missed detections. In the case of safety-oriented systems (such as automatic emergency braking, blind-spot detection and obstacle detection at level crossings), radar's degraded performance can result in accidents. Therefore, it is important to mitigate the effect of mutual interference to make modern radar applications safe and reliable. The goal of this work is to develop signal processing techniques for interference mitigation in frequency modulated continuous wave (FMCW) radars operating at 77-81 GHz. The thesis investigates radar interference suppression in the spatial domain, using antenna arrays. The interference is suppressed by placing notches in the antenna radiation pattern in the direction of the interference source by employing digital beamforming. The array aperture (size) determines the beam-width and notch resolution of the receiving antenna. Narrow notches are desirable since they lead to a smaller suppressed region in the radar's field of view. It is demonstrated that an extended virtual aperture in a multiple-input-multiple-output (MIMO) FMCW radar does not offer an improved notch resolution for interference suppression due to a non-coherent interference signal in the virtual aperture. Moreover, it is shown that the calibration mismatches of the receiving array completely change the final antenna beam-pattern compared to the theoretical one. Additionally, an adaptive beamforming approach of interference suppression based on the least mean squares (LMS) algorithm is presented, which is evaluated using outdoor measurements from a 77GHz FMCW radar. The results demonstrate that the proposed technique suppresses interference successfully, resulting in a signal to interference plus noise ratio (SINR) improvement. It is also shown that complex-baseband (IQ) receivers achieve better interference suppression compared to real-baseband receivers when spatial domain methods are employed. The final research publication deals with interference mitigation in the time-domain intermediate frequency signal. The disturbed samples in the received signal are detected, removed, and reconstructed based on an estimated autoregressive (AR) signal model. The baseband signal coherence in both fast- and slow-time makes it possible to perform signal reconstruction in both dimensions. With the help of outdoor measurements covering selected scenarios, it is demonstrated that by carefully selecting the signal reconstruction dimension, a better SINR and side-lobe suppression can be achieved.

Fokus idag ligger på självkörande fordon, fler och fler inom fordonsindustrin utvecklar och forskar inom ämnet. En bit av ämnet är adaptiv farthållare som används för att undvika och minska kollisioner mellan objekt under kolonnkörning. Detta utförs genom att beräkna sträckor upp till 250 m med en distanssensor för långa avstånd och reglera gasreglaget och bromssystemet. Sensorerna kommer att vara grunden till detta arbete. Rapporten tar upp två typer av sensorer som klarar av att mäta längre sträckor, radarsensor som använder sig av radiovågor och lidarsensor som använder laserstråle. Litteraturstudie över befintlig forskning inom ämnet påvisar att olikheter mellan sensorerna finns och de har sina för- och nackdelar. Det som skiljer dem åt är upplösning av objektet och väderförhållanden, vilket kan vara avgörande vilket resultat man strävar efter. För att få reda på vad marknaden har att erbjuda utfördes en jämförande studie. Där ett fåtal sensorer valdes ut för att jämföras och presenteras. I blockschemat visas en skillnad i uppbyggnad av systemet, då det gäller mellan sensorerna radar och lidar. Skillnaderna är på komponentnivå eftersom de använder sig av olika tekniker. Ett övergripande blockschema över systemet presenteras och ett förslag på en arkitektur läggs fram med ett mer specifikt blockschema. / The focus today is on self-driving vehicles, more and more in the automotive industry are developing and researching the subject. One piece of the subject is adaptive cruise control that is used to avoid and reduce collisions between objects during convoy driving. This is accomplished by calculating distances up to 250m with a long-distance sensor and adjusting the throttle and braking system. The report addresses two types of sensors capable of measuring longer distances, radar sensors using radio waves and lidar sensors using lasers. The sensors will be the basis for this work. A literature review of existing research in the subject shows that differences between the sensors exist and that they have their advantages and disadvantages. Where the sensors differentiate them is the resolution of the object and the weather conditions, which can determine which result you are aiming for. In order to find out what the market has to offer, a comparative study was conducted. Where a few sensors were selected for comparison and presentation. Where the block diagram indicates that there are differences between radar and lidar of the system structure. The differences are at the component level because they use different techniques. An overall block diagram of the system is presented and a proposal for an architecture is presented with a more specific block diagram.

As part of the international EU project Integrid, Ellevio has started a pilot project where measurement equipment has been installed in secondary substations in Stockholm Royal Seaport. The purpose of the pilot project is to improve operation, maintenance and future planning of the grid. This thesis focuses on predictive maintenance and data analysis of power quality parameters and aims to cover several areas within these two categories to answer the following research questions: -In what ways can the life-cycle and faults of components be used as a basis for predictive maintenance? -Are there any measurable parameters - currently being monitored or not - that can be useful for Ellevio in terms of maintenance and grid development? -Is the installation of more monitoring systems worthwhile, and if so, what should be monitored? -Is it possible to find indicators that allow for predictive maintenance to reduce the interruption time and maintenance cost? The main results are that the focus should lie on middle voltage (MV) cables due to its significant contribution to SAIDI and SAIFI. Monitoring partial discharges in MV cables could potentially lower the frequency of faults. A study needs to be conducted to establish the extent of partial discharges as a source of faults. Furthermore harmonic content was found to have a large impact on transformer losses and this parameter should be considered when dimensioning new secondary substations. Another parameter that had interesting results is the current unbalance which led to high neutral currents and caused high losses.

The interest in renewable energy has significantly increased in the last decades which has led to an increased amount of renewable energy sources in the grid. In the Nordic grid, the major contribution to renewable energy is hydro power and wind power and an increase in the amount of wind power is expected in the future. The increase in wind power and decommissioning of nuclear power is expected to decrease the mechanical inertia in the system which helps to stabilise the electrical grid frequency. The inertia is expected to decrease by a factor of two within 20 years and other solutions for frequency stability must be implemented to assure a stable power system. At Uppsala University several projects are investigating how grid-connected energy storages can increase the frequency stability with a high penetration of intermittent renewable energy sources. In this thesis, a linear synthetic inertia control algorithm is implemented on a national Instruments FPGA for controlling the power flow from a supercapacitor energy storage via a two-level three-phase inverter. The control strategy is evaluated both via simulations and experimental tests in a nano grid. The results of the simulations and experimental work are presented and show that it is possible to calculate the frequency derivative in real time to reduce the frequency ROCOF and nadir. The results of the increased frequency stability are presented.

No description available.

ABB HVDC is a manufacturer of optical current transducers (OCTs) are used which are used to measure alternating currents in high voltage applications. The sensor used today is based on a current transformer and measures alternating currents between 100 and 4000 A. With the current transformer there are disadvantages due to its core of magnetic material which saturates at high currents. As the core goes into saturation, the number of different variants of current transducers increases re-garding rated currents, measurement requirements and behavior in short-circuit currents and transients. Due to such a limitation, there is the need for an alternative solution. The Rogowski coil is just like the current transformer based on Faraday's law of in-duction. Instead of several different variants, a solution with Rogowski coils can be varied with different measuring ranges of the sensor electronics. Therefore, the possibility of implementing a Rogowski coil in an OCT is being investigated. An OCT consists partly of the sensor itself but also an electronics unit and an optical in-terface unit (OIU). Since the signal from a Rogowski coil is proportional to the derivative of the current in the measurement object, a type of integrator is needed to recreate the signal. The possibility of having either an analog or digital integrator exists, but a digital can bring benefits such as reduced delivery time. By utilizing existing circuits on the OIU, a digital integrator could be implemented. In the work, an integrator function has been created in Matlab to recreate the signal. A scale factor was determined to minimize the amplitude difference between reference sensors and the Rogowski sig-nal. The work shows that current measurement with the Rogowski coil where the fre-quency is varied results in an amplitude difference between the reference sensor and the Rogowski coil. The amplitude difference has a linear trend and could be offset by a frequency coefficient. The work also discusses proposals for further tests that should be performed to identify how different factors affect a current measurement. / På ABB HVDC tillverkas optiska strömgivare (OCT) som används för att mäta väx-elströmmar i högspänningsapplikationer. Givaren som används idag är baserat på en strömtransformator och mäter växelströmmar mellan 100 och 4000 A. Med ström-transformatorn följer nackdelar på grund av dess kärna av magnetiskt material som går i mättnad vid höga strömmar. Till följd av att kärnan går i mättnad så ökas anta-let olika varianter på strömgivare med hänsyn till märkströmmar, mätkrav och bete-ende vid kortslutningsströmmar samt transienter. På grund av en sådan begränsning finns behovet av en alternativ lösning. Rogowski-spolen är precis som strömtransformatorn baserad på Faraday’s indukt-ionslag. En lösning med Rogowski-spolar kan istället för flera olika varianter, varie-ras med olika mätområden hos givarelektroniken. Därför undersöks möjligheten att kunna implementera en Rogowski-spole i en OCT. En OCT består delvis av själva givaren men även en elektronikenhet samt en optisk gränssnittsenhet (OIU). Eftersom signalen från en Rogowski-spole är proportionell mot derivatan av ström-men i mätobjektet så behövs en typ av integrator för att återskapa signalen. Möjlig-heten att ha antingen en analog eller digital integrator finns, men en digital kan med-föra fördelar som exempelvis minskad leveranstid. Genom att ta nytta av befintliga kretsar på optiska gränssnittsenheten skulle en digital integrator kunna implemente-ras. I arbetet har en integratorfunktion skapats i Matlab för att återskapa signalen. En skalfaktor bestämdes för att minimera amplitudskillnaden mellan referensgivare och Rogowski-signalen. Arbetet visar att strömmätning med Rogowski-spole där frekvensen varieras medför en amplitudskillnad mellan referensgivare och Rogowski-spole. Amplitudskillnaden har en linjär trend och skulle kunna motverkas genom en frekvenskoefficient. I arbe-tet diskuteras även förslag på ytterligare tester som borde utföras för att identifiera hur olika faktorer påverkar en strömmätning.

Turbocharging is a way to stay competitive on the market where there are increasing demands on fuel consumption and engine performance. Turbocharging lets the engine work closer to its maximum power and thereby reduces the relative losses due to pumping and friction. The turbocharger is exposed to big temperaturedifferences and heat flows will occur both internally between the turbine and the compressor as well as between the turbocharger and its surroundings. Away to get a better understanding of the behaviour of the turbocharger is to understand the heat flows better. This thesis is therefore aimed at investigating theeffect of heat transfer on the turbocharger. In the thesis, different ways of accountfor the heat transfer within the turbocharger is investigated and a heat transfermodel is presented and validated. The model can be used as a tool to estimate theimportance of different heat flows within the turbocharger. A set of heat transfer coefficients are estimated and the heat transfer is modelled with good accuracyfor high engine loads and speeds.

Coming stringent regulatory emissions requirements with Real Driving Emissions testing amplifies the need for efficient engine control at all driving scenarios. This thesis has investigated the air-flow transients that appears when changing the throttle position very fast, such as at a stop sign. Available information about the intake manifold temperature is today mainly sensor-based or zero-dimensional. Since the temperature of the air affects the fuel controller(s)and is believed to be able to help the knock-controller as well, a more detailed description of the temperature is warranted. Three different one-dimensional interpretations of the intake manifold has been modeled and one of them is implemented in a full air-path simulation - from the throttle to the exhaust. The best suited simulation model is validated against measurement data and compared to the well know adiabatic control volume model, which is zero-dimensional. The effect on the temperature contributed by the VVT, turbo, throttle-settings and engine speed was tested in a test cell. The results shows that the computational efficiency varies between the different one-dimensional intake manifold models and that one-dimensional accuracy comes at a great cost of computational power. The testing and validation showed that the pressure difference and throttle ramping time had a big impact and that the positive transients are more predictable with current models, compared to the negative transients.