Imagine that the technical development can take the ultrasound measurement systems from the large piece of machinery today, to a coin size system tomorrow. The factor that has reduced the size of electronic systems over time is integration and integrated circuits. In this thesis circuit simulator models of complete ultrasound systems are used to design custom integrated circuits. These circuits are optimized for low power consumption and small size. The models that are used predict the acoustic behavior of an ultrasound system in a simulated measurement situation. This allows the design of integrated electronics to be customized to a specific measurement application, where performance can be validated, in one tool only. The work in this thesis is excitation and reception electronics for general ultrasound measurement equipment, as well as specific electronics aimed for the ultrasound energy measurement situation. These electronic circuits show that size and power consumption of ultrasound measurement systems can be reduced significantly with the use of integration. / <p>Godkänd; 2005; 20060922 (ysko)</p>

This thesis describes the exploration of a method to measurethe droplet size and the concentration of atmospheric liquid water. The purpose is to find a cost effective technique to detect the conditions for icing on structures. Icing caused by freezing atmospheric water can be a signifi- cant problem for infrastructure such as power lines, roads and air traffic. About one third of the global installed wind power capacity is located in cold climates, where icing of rotor blades is one of the major challenges. The icing process is complex and the result depends on a combination of the aerodynamic shape of the structure or airfoil, the velocity of the air and its contained water, the temperature, the mixing of snow and water, the concentration of liquid water and the Droplet Size Distribution (DSD). The measurement method is based on a shadowgraph imag- ing system using light emitting diode (LED) light as background illumination and digital image processing. A prototype instru- ment has been constructed. The components were selected keeping the possibility of low-cost volume production in mind. The applications of a commercial instrument based on this tech- nique are e.g. real-time in-situ icing condition measurements and assimilation and verification of data in numerical weather models. The work presented shows that measurements of the size and concentration of water droplets using shadowgraph images can be used for the comparison and validation of Numerical Weather Prediction (NWP) models and other instruments. The accuracy of the particle size measurement is high. The accuracy of the concentration measurement has the potential to become high due to the single-particle measurement range calibraiton. The precision of the instrument depends mainly on the number of images that is used to find each measurement value. The real-time performance of the instrument is limited by the image retrieval and processing speed and depends on the  precisionrequired. / <p>Vid tidpunkten för framläggningen av avhandlingen var följande delarbeten opublicerade: delarbete 3 inskickat.</p><p>At the time of the defence the following papers were unpublished: paper 3 submitted.</p> / SMART (Smarta system och tjänster för ett effektivt och innovativt samhälle)

Electric vehicles (EV) in the transportation sector will play a major role in achieving low-carbon emissions from the mobility of vehicles. With a future increase in electric vehicles and autonomous electric vehicles, the demand for charging increases and this comes with new problems that require modern solutions. The integrity of the power grid infrastructure can be at risk as grid congestion and power mismatch can cause problems as the act of charging the vehicles adds an extra burden on the power grid. Today, there exist several scenarios on how a vehicle can be charged and a number of technical solutions that are advantageous based on different aspects such as user's need, price of the electricity, and electricity network.   This thesis focuses on identifying different charging scenarios in mapping the information that is required and studying the effects of these charging scenarios through a smart charging algorithm. A smart charging algorithm to optimise for charging and discharging of the electric vehicle is developed and tested in a MATLAB environment with the aim to achieve a balanced grid load profile. The simulation results verify the potential of the algorithm to reduce the adverse effects of electric vehicle charging. Additionally, a model to map autonomous electric vehicles to charging station in accounts of a low state of charge is also developed in MATLAB

Different techniques are used for demand forecasting within the In-dustry such as statistical methods like Croston, ARIMA and exponen- tial smoothing methods, Also, During these days Machine learningtechnologies such as SVM, NN and gradient boosting are also usedfor demand forecasting. Both statistical and Machine learning mod- els are widely used in the Industry for demand forecasting basedon performance, requirements, technical availability and data. In thisresearch, we will be dealing with intermittent demand forecasting,which means the data has a large number of zero values within thesales and this is done in connection with Volvo trucks. We will be ex-perimenting with both statistical and Machine learning approaches toevaluate how both statistical and machine learning models respondto the data that we have. Also, we will be introducing a novel hybridapproach where we combine both statistical and Machine learning models into an ensemble architecture(hybrid modelling) which im-proved the performance or prediction accuracy for Intermittent data.In this, the ensembles will be formed by creating metadata combining inputs and predictions from individual models and using the meta- data to train other machine learning models in-order to get predic-tions. We will be using the data from the Volvo trucks supply chaindivision to conduct our experiments and evaluation of the results.The contribution of this paper is twofold. During our experiments,we found out how each model from statistical as well as machinelearning model fits with the data that we have. We also introduced a novel hybrid approach with ensembles combining both statistical aswell as machine learning in a meta-model architecture. Along withimplementing the hybrid model, we compare the best out of the sta- tistical and machine learning models with our hybrid ensemble ap-proach which proves to reduce the predictions error(lesser error) to 6percentage lesser from the best performing individual model.Secondly,we focused on bringing confidence prediction into intermittent de-mand forecasting. The confidence prediction brings a certainty factorin to the predictions, which is the second major contribution of ourresearch. In our approach of confidence prediction, we came up with a confidence of 95 per cent which shows that we are 95 per cent cer-tain that the value will fall in the range of our prediction interval.And we also made sure that the prediction bandwidth with such alarge confidence interval is not too wide so that it doesn’t affect tothe safety stock maintenance in the warehouse thus can reduce thestock accumulation in case of adverse conditions that affect the sales.

This report provides a description of creating a circuit board, designed for a cable-based control system in a BLDC engine. The objective of the project was to examine how effective a replacement of cables with a circuit board would be, to make the control system more compact. A software named Kicad was used to create a layout, later - the created digital model was ordered, and all the necessary components were installed on the circuit board. At first, all the cable connections were examined in terms of functions, and later - a circuit scheme was created to clarify the connections. The design of the circuit board was completed with respect to all kinds of interference and its impact on the system. In the theory subsection, it is explained in detail how the design of the layout was made with respect to white noise and other kinds of interferences. The result subsection provides a demonstration of the functionality and robustness of the created circuit board.

No description available.

The complexity of electrical systems present in vehicles is continuously rising and the number of interconnected electrical devices is growing during the strive for optimization and reaching higher efficiency levels. Actuation of said devices have the possibility of injecting voltage and current harmonics into the system, thus negatively affecting neighbouring devices. A measurement method for detecting the transient currents originating from such devices was therefore desirable. Focus was placed on current transients with frequency components within the range 1 kHz to 1 MHz. The report presents theory regarding current sensing techniques, where sensors based on the Rogowski coil were chosen for further implementation. Signal analysis theory included choice of sampling frequency and the FFT approach. Different data acquisition hardware were considered for usage with the current sensors, and evaluated both in field and a laboratory environment. Compiled application notes for the end-user of the measurement method are presented. Laboratory tests showed that Rogowski sensors were capable of measuring the transient currents with the desired spectral resolution. Caution should however be taken when measuring and interpreting low frequency components due to the droop effect. Among the evaluated Rogowski sensors, the sensor type 30LFB was found to be best fitted for measuring current transients originating from electrical loads in a vehicle. Different power cable set-ups can act on the system with low-pass characteristic. Field tests showed that the energy demand of an electrical unit is not solely supplied by the battery but also neighbouring devices. Most prominently were a 40 kHz component that could be seen propagating from the electronic clutch actuator to other loads. However, the majority of the currents’ frequency components with considerable amplitudes were located outside the delimited spectrum. It was concluded that sampling hardware have the possibility of injecting the quantified waveform with frequency components that are related to the sampling frequency.

To measure the current impulses before a discharge process in an insulation material is completed a proposed system has been built theoretically. The blocks in the system have been studied by going through relevant sources and meetings with the supervisor of the project and new ideas have been considered.  With the goal of having a proposed theoretical circuit that can measure current impulses with a peak of 100A, some methods have been excluded and some have been put into the system. Exclusion of some methods are because there was not enough time to dig into a completely new approach for all the methods, and therefore some methods were studied more deeply than others.  The project started with a lot of reading to get understanding of the fundamental process of long air gap discharges and continued with putting the theory into a simulated system for measuring current.  The proposed system has been simulated and a result has been drawn from this by looking into the bandwidth, the sensitivity and accuracy of the system.

No description available.

The power grid must expand rapidly to meet future capacity needs. Society's electrification and transition to transient energy sources, as well as the advent of micro-production means that the electricity grid must change. Since there is a shortage of capacity in the electricity networks already, it is necessary to look at alternatives that could reduce the need for capacity. One such alternative is “demand side flexibility”. That means that the user adjusts his electricity consumption according to production. The adjustment means that consumption is reduced or increased as needed, but also that consumption can be moved to an earlier or later occasion.   The local electricity network of Umeå Energi that is powered by distribution station S is a rural network with 1018 subscribers supplied by 49 substations, this electricity network is examined using network analyzes at the medium-voltage level for two different cases. In each case, both network expansion and demand side flexibility are studied as a solution to the capacity shortage. The first case deals with the emergence of electric car charging in the electricity grid, while the second case deals with expansion of micro-production in the electricity grid. The study of these two cases showed that demand side flexibility can solve the lack of capacity effectively, but in the long term, network expansion is a better and more economically profitable alternative. The first case declares that the cost of network expansion corresponds to the cost of 3.26 years with demand flexibility while the second case says that a period of 0.84 years with demand flexibility will reach the cost of a network expansion. The biggest found economic difference is that the network expansion has only non-recurring costs, while the cost of demand flexibility consists of both non-recurring costs and recurring costs. / Elnätet måste byggas ut snarast för att klara av framtida kapacitetsbehov. Samhällets elektrifiering och övergång till transienta energikällor samt tillkomst av mikroproduktion gör att elnätet måste utvecklas. Eftersom det råder kapacitetsbrist i elnäten redan nu så måste det beaktas alternativ som kan hantera kapacitetsbehovet, ett sådant alternativ är efterfrågeflexibilitet. När användaren justerar sin elkonsumtion vid behov kallas detta för efterfrågeflexibilitet. Justeringen innebär att konsumtionen minskas eller ökas vid behov, men även att den flyttas till ett tidigare eller senare tillfälle.   Umeå Energis lokalnät som matas ifrån fördelningsstation S är ett typiskt landsbygdnät med 1018 abonnenter som försörjs av 49 nätstationer, detta elnät undersöks med hjälp av nätanalyser på mellanspänningsnivån för två olika fall. I vartdera fall undersöks både nätutbyggnad och efterfrågeflexibilitet som lösning på kapacitetsbristen. Första fallet behandlar tillkomst av elbilsladdning i elnätet, medan det andra fallet behandlar expansion utav mikroproduktion i elnätet. Studien av dessa två fall visade att efterfrågeflexibilitet kan lösa kapacitetsbristen effektivt, men långsiktigt är nätutbyggnaden ett bättre och mer ekonomiskt lönsamt alternativ. Det första fallet konstaterar att kostanden för nätutbyggnad motsvarar kostnaden för 3,26 år med efterfrågeflexibilitet, andra fallet fastställer att det räcker med en tidsperiod på 0,84 år med efterfrågeflexibilitet för att nå kostanden för en nätutbyggnad. Den största ekonomiska skillnaden är att nätutbyggnaden har engångskostnader medan kostnaden för efterfrågeflexibiliteten består utav både engångskostnader och rörliga kostnader.