In recent years, the electrification of technology that is traditionally powered by fossil fuels has become a popular means to reduce greenhouse gases (GHG). Although the intentions are well founded, the strain on the electrical grid is seldom taken into consideration. When there is increased load on the grid, it is typically met by fossil fuel peaking power plants or additional fossil fuel infrastructure. Depending on the electrical generation technology deployed and the power plant efficiency, electrification can result in an increase in GHG emissions. To make better informed decisions for GHG reductions, policy makers and engineers are in need of smart energy systems, such as the Integrated Community Energy and Harvesting (ICE-Harvest) system. ICE-Harvest systems work with and can respond to changes on the electrical grid, providing demand response. The system creates electrical demand when renewable generation sources are available, reduces demand when fossil fuel generation is present, and can offset centralized generation using distributed combined heat and power resources. In this thesis, steps to design a micro-thermal network (MTN) for the ICE-Harvest system are outlined and different operational strategies are explored that respond to grid behaviour in real time. How fast the thermal network reacts to grid level variations is defined as the response time. The physical response of the thermal network is a temperature set point change. A design map was developed presenting multiple parameters that contribute to the response time, the trade-offs between them, and the corresponding temperature difference achievable. Through developing models in the equation-based object-oriented software Dymola, the viability for real time temperature set point changes in micro-thermal networks was explored. The MTN and the energy transfer stations (ETSs) that transfer energy between the thermal network and the buildings have been modeled. Yearly system simulations were conducted to analyze the corresponding performance of the MTN in terms of electrical requirements and overall GHG emissions. An operational range of the system was presented demonstrating the flexibility of the ICE-Harvest system. The simulation results have identified the ICE-Harvest system as a viable means to provide demand response to the grid and to reduce GHG emissions. Future work and recommendations will be made to improve the response of the system and further reduce electrical consumption and GHG emissions. / Thesis / Master of Science in Mechanical Engineering (MSME)

The thermal regime of a gearbox is of considerable importance to its performance. Several significant gearbox parameters, such as the efficiency and fatigue life of its components, are temperature dependent. It is thus important to be able to determine the temperatures of the gearbox components during operation, but they are difficult to measure experimentally. A simulation model capable of predicting these temperatures would therefore be a valuable tool. The objective of this master’s thesis was to create a model capable of simulating the thermal regime of a truck gearbox during operation. To do this, mechanical losses in the gearbox, heat exchange with the surroundings, as well as heat transfer between components had to be accounted for. The model was created using the 1D simulation software LMS Imagine.Lab Amesim 14.0, and is based on a combination of mechanical and thermal networks. Details of the mechanical and thermal interactions between components are calculated using empirical and analytical formulas for mechanical losses and heat transfer. The result of the thesis is a model which can be used to simulate either real or idealised load cases, from which temperatures of gear wheels, shafts, bearings, housing and gearbox oil may be studied, as well as gearbox losses and heat transfer. Comparisons between simulated and measured gearbox efficiencies show good correlation. It is also shown that the model can predict oil temperatures which agree with in-vehicle measurements. Due to a lack of measurement data, most simulated component temperatures cannot be compared to measured values. However, temperature measurements performed for one of the gear wheels indicate that the model can be used to predict their temperature. In order to demonstrate the capabilities of the model, example results from both real and idealised load cases are presented.

Unmanned Air Vehicles (UAVs) are becoming more widely used in both military and civilian applications. Some of the largest UAVs have power systems equivalent to that of a military strike jet making power management an important aspect of their design. As they have developed, the amount of power needed for loads has increased. This has placed increase strain on the on-board generators and a need for higher reliability. In normal operation these generators are sized to be able to power all on-board systems with out overheating. Under abnormal operating conditions these generators may start to overheat, causing the loss of the generator's power output. The research presented here aims to answer two main questions: 1) Is it possible to predict when an overheat fault will occur based on the expected power usage defined by mission profiles? 2) Can an overheat fault be prevented while still allowing power to be distributed to necessary loads to allow mission completion? This is achieved by a load management algorithm, which adjusts the load profile for a mission, by either displacing the load to spare generators, or resting the generator to cool it down. The result is that for non-catastrophic faults the faulty generator does not need to be fully shut down and missions can continue rather than having to be aborted. This thesis presents the development of the load management system including the algorithm, prediction method and the models used for prediction. Ultimately, the algorithms developed are tested on a generator test rig. The main contribution of this work is the design of a prognostic load management algorithm. Secondary contributions are the use of a lumped parameter thermal model within a condition monitoring application, and the creation of a system identification model to describe the thermal dynamics of a generator.

Syfte – Syftet för denna studie var att utveckla en sensorlös modell som beräknar en estimeradtemperatur i en BLDC-motors statorlindningar, detta för att undersöka hur väl det går attskydda handhållna produkter mot oaktsam användning och för att kunna motverka körningunder höga temperaturer, vilket skulle kunna förlänga livslängden för handhållna produkter. Metod – Denna studie har använt forskningsmetoden Design Science Research för att utvecklaen artefakt som sensorlöst estimerar temperatur i en BLDC-motors statorlindningar.Artefaktens prestanda för den estimerade temperaturen var noggrannhet, precision ochkonvergeringstid, vilket utvärderats genom analys av kvantitativa data som samlats in underolika experiment. Resultat – Den utvecklade artefakten i studien baserades på en kombination av CurrentInjection och Lumped Parameter Thermal Network samt ett Kalman Filter, artefaktensprestanda uppfyllde inte Husqvarna AB:s krav. Artefaktens precision och noggrannhet för att estimera temperatur i en BLDCmotorsstatorlindningar blev 7,2 °C ± 23,8 °C och dess konvergeringstid blev 7,3 sför dess medelvärde och 18,4 s för dess precision. Implikationer – Denna studie och dess resultat kan användas som en hänvisning på hur välen kombination av Current Injection, Lumped Parameter Thermal Network och Kalman Filterkan estimera temperaturen i statorlindningar för BLDC-motorer med en resistans på 20 mΩ,induktans på 10 uH, nominell hastighet på ~20 000 RPM med terminering av typen Delta ochsom är icke salient. Begränsningar – Studiens begränsningar listas nedan. Utvecklingstiden för artefakten utfördes under begränsad tid. Vilket bidragit till mindre optimering av artefakterna. Vilket bidragit till färre iterationer av artefakter. Artefakten utvärderas endast på VESC hårdvara och dess mjukvara som grund.Artefaktens prestanda påverkas av noggrannheten samt precisionen vidmätning av ström och spänning. Experimenten som utfördes var begränsade. Hade intervallen som experimenten utfördes gällande temperatur, hastighetoch dynamisk last varit större skulle artefaktens prestanda kunna bli undersökti mer verkliga förhållanden. En bättre bromsbänk och en klimatkammareskulle använts. Endast en BLDC motor utvärderades. Utvärdering av fler motorer skulle kunna visa på skillnader i prestanda förartefakten mellan olika mindre motorer, det vill säga visa på dess generellatillämpbarhet. Analys av artefaktens prestanda vid enbart konvergerande tillstånd utfördes inte. Vilket skulle kunna visa på om artefaktens prestanda vid enbart konvergeradetillstånd hade uppfyllt Husqvarna AB:s krav. Nyckelord – Estimera Temperatur, BLDC-motor, Statorlindningar, Current Injection,Lumped Parameter Thermal Network, Kalman Filter, VESC / Purpose – The purpose of this study was to develop a sensorless model that calculates anestimated temperature in a stator winding of a BLDC motor, to investigate how well it is possibleto protect handheld products from inadvertent use and to be able to counteract operation underhigh temperatures, which could prolong service life of the handheld products. Method – This study has used the research method Design Science Research to develop anartifact that sensorlessly estimates temperature in a BLDC motor's stator windings. Theperformance of the artifact for the estimated temperature is accuracy, precision, andconvergence time, which was evaluated by analysing quantitative data collected during differentexperiments. Findings – The artifact developed in the study is based on a combination of Current Injectionand Lumped Parameter Thermal Network and a Kalman Filter, the performance of the artifactdid not meet Husqvarna AB's requirements. The precision and accuracy of the artifact for estimating temperature in a statorwinding of a BLDC motor was 7,2 °C ± 23,8 °C and its convergence time was 7,3 sfor its mean and 18,4 s for its precision. Implications – This study and its results can be used as a reference regarding how well acombination of Current Injection, Lumped Parameter Thermal Network and Kalman Filter canestimate the temperature in stator windings for non-salient BLDC motors with a resistance of20 mΩ, inductance of 10 uH, nominal speed of ~20 000 RPM with termination of the Deltatype. Limitations – The limitations of the study are listed below. The development time for the artifact was performed for a limited time. Which has contributed to less optimization of the artifacts. Which has contributed to fewer iterations of artifacts. The artifact is evaluated only on VESC hardware and its software as a basis.The performance of the artifact is affected by the accuracy and precision inmeasuring current and voltage. The experiments performed were limited. Had the intervals at which the experiments were performed regardingtemperature, speed and dynamic load been greater, the performance of theartifact could have been examined in more real conditions. A better brakebench and a climate chamber would be used. Only one BLDC motor was evaluated. Evaluation of more motors could show differences in the performance of theartifact between different smaller motors, that is, show its general applicability. Analysis of the performance of the artifact in convergent states alone was notperformed. Which could show if the performance of the artifact could fulfill HusqvarnaAB's requirements if the analysis were only performed in convergingconditions. Keywords – Estimate Temperature, BLDC Motor, Stator Windings, Current Injection,Lumped Parameter Thermal Network, Kalman Filter, VESC

The energy crisis together with greater environmental awareness, has increased interest in the construction of low energy buildings. Fabric thermal storage systems provide a promising approach for reducing building energy use and cost, and consequently, the emission of environmental pollutants. Hollow core ventilated slab systems are a form of fabric thermal storage system that, through the coupling of the ventilation air with the mass of the slab, are effective in utilizing the building fabric as a thermal store. However, the benefit of such systems can only be realized through the effective control of the thermal storage. This thesis investigates an optimum control strategy for the hollow core ventilated slab systems, that reduces the energy cost of the system without prejudicing the building occupants thermal comfort. The controller uses the predicted ambient temperature and solar radiation, together with a model of the building, to predict the energy costs of the system and the thermal comfort conditions in the occupied space. The optimum control strategy is identified by exercising the model with a numerical optimization method, such that the energy costs are minimized without violating the building occupant's thermal comfort. The thesis describes the use of an Auto Regressive Moving Average model to predict the ambient conditions for the next 24 hours. A building dynamic lumped parameter thermal network model, is also described, together with its validation. The implementation of a Genetic Algorithm search method for optimizing the control strategy is described, and its performance in finding an optimum solution analysed. The characteristics of the optimum schedule of control setpoints are investigated for each season, from which a simplified time-stage control strategy is derived. The effects of weather prediction errors on the optimum control strategy are investigated and the performance of the optimum controller is analysed and compared to a conventional rule-based control strategy. The on-line implementation of the optimal predictive controller would require the accurate estimation of parameters for modelling the building, which could form part of future work.

This thesis deals with thermal calculation of asynchronous motor. The theoretical part deals with principles of heat transfer, which are important for thermal calculation. Another theoretical part describes asynchronous motor analysis and its loss. In the practical part, these losses together with the electromagnetic circuit are calculated. Subsequently, two thermal networks are created to calculate the warming of individual machine parts. To ensure the correctness of the result, a bound model of partial calculations of the asynchronous machine is created. The next step is to compare the calculated electrical quantities and the calculated temperatures with respect to the measured values.

Thermal effects in integrated circuits have increasing impact on chip's lifetime and function. For this reason, the chips must be subjected to electro-thermal simulations prior to the launch of production in order to avoid potential circuit failures. Therefore, in the first part of this diploma thesis these effects and methods of creating thermal models are described. The thesis also explores available tools for electro-thermal simulations and the way these simulators work. In the practical part of the thesis, the operation of electro-thermal simulation in the Eldo tool is verified, a method of automated thermal network creation is proposed and a application for its generation based on the circuit layout is implemented. The results of the electro-thermal simulation with the generated thermal network are compared with the results of the currently used method.

This master´s thesis deals with ventilation of synchronous generators with a cylindrical rotor. For the design of ventilation we apply basic physical laws in the field of hydromechanics and thermomechanics. Therefore the first chapters are devoted to these subjects. They are followed by the description of ventilation systems and a thermal net is created and solved for one of them consisting of the thermal resistance and sources. The final part deals with a program, which I developed in Visual Basic 2008 Express Edition. This program enables to calculate the ventilation and heating of individual parts of the machine after entering basic machine dimensions and losses.

This thesis is focus on thermal analysis of aircraft electronic devices and their cooling possibilities. The two analytic methods of thermal analysis are applied on two particular technical objects. The laboratory experiment of non-contact temperature measurement method is applied on real unit. The results of simulation are compared with results of experiment.

This paper deals with interaction of different physical phenomena in asynchronous motor. The first part of this work is devoted to computing of electrical ratios in asynchronous motor. By using the equivalent circuit in the shape of Gamma-circuit the equation for computing of currents, performances and losses of asynchronous motor are derived. The second part describes calculating of electromagnetic circuit and iron-core losses. In the next part there is the first part of associated model created which respects electric and electromagnetic ratios in the asynchronous motor. This model can be used for example to pursuance of variation of flux density caused by resizing load. In this model the unconventional way of computing the magnetizating inductance and resistance coresponding to iron-core losses is used. The next part deals with calculation of machine warming using the thermal network. In the last part there is a complete coupled model assembed which respects the interaction of electrical, electromagnetical and thermal ratios of induction machine.