No description available.

Development today has moved more towards battery technology, partly due to the increased demand of electric vehicles (EVs). The quest for a sustainable society is at an all-time high, with electrification of almost all devices only being the beginning. Due to the use of the fragile Lithium-Ion battery, a system that controls and monitors the battery must be implemented to ensure that it operates normally. A system like this is often referred to as a Battery Management System (BMS), in this case for Lithium-Ion batteries. The objective in this thesis is to construct a modular BMS playground for NEVS in Trollhättan to continue development on. The interface for the system will consist of Controller Area Network (CAN), a fast and robust communication protocol used in almost all personal vehicles today, and Isolated Serial Peripheral Interface (isoSPI), an isolated adaptation of one of the most common communication protocols used in sensors and microcontrollers so far. The BMS will be constructed of four individual subsystems using Arduino, each with a different purpose. These four subsystems are later merged into one BMS system to offer communication between CAN and isoSPI, thus supporting a future integration of this BMS to the Vehicle Control Unit of an EV. Moreover, since the BMS is going to be developed for a vehicle, modes for engaging the vehicle to drive and stop will be made. In order to provide some safety measures, automatic disconnection of the battery in case of an error will be added. The BMS with the previously mentioned features, also capable of doing voltage measurements with a safe connection/disconnection of the battery was then made. Features such as current and temperature monitoring were omitted due to time constraints and will in the future instead be done by NEVS along additional features. This thesis was conducted by Karlstad University and NEVS in Trollhättan, Sweden.

No description available.

This project is aimed at developing a simulation model in Simulink for a new startup system controlling the marine current turbine at Uppsala university's research facility in Söderfors. The goal is to design a circuit that is able to switch between feeding power to and extracting power from the synchronous machine in order to control the rotational speed of the turbine. The technical solution consisted of two separate circuits combined into the final system. First, the synchronous machine is run as a BLDC motor where power is fed to the motor in order to accelerate the turbine. Then, at a specified rotational speed threshold the BLDC circuit is disconnected and the turbine continues to accelerate by picking up power from the water alone. Lastly, when the rotational speed reaches the desired setpoint for the rotational speed the synchronous machine is connected to a DC load. By controlling the power extracted in the load with a PI controller the rotational speed of the turbine stays at the setpoint value. Results from the simulation model shows that it is possible to control the startup process of the turbine with such a system. In future projects improvements can be made regarding removing current spikes, more smooth power usage and faster PI controllers. To further develop the startup system the next step would be to translate the simulation model into LabVIEW code in order to test it at the site in Söderfors.

This report covers a project that set out to create our own and implement another existing measurement system that measures the power consumption in different student residences with higher resolution then what is currently offered by Vattenfall. This is important since there is a problem in Uppsala with a lack of power from the electrical grid which limits Uppsalas ability to grow as a city. Different dorm rooms in the housing area Gamla Studenstaden were then measured and data with the resolution of 1 minute was then analysed. This data was then used in order to answer which type of accommodation is most efficient with its power usage in relation to the amount of rooms. This report also wanted to answer how different types of accommodations cause spikes in their power usage which are only possible to spot with the higher resolution. The resulting data show that one-room apartments has relatively low power consumption over the day but contribute to so called power spikes which cause large load on the power grid. The dorm rooms did however seem to have a more distributed power consumption over the day.

No description available.

No description available.

In 2014 KTH Royal Institute of Technology initiated a space technology and research center, KTH Space Centre. MIST (MIniature Student saTellite) is the rst student project conducted at KTH Space Centre and also the rst student satellite from KTH with a predicted launch in 2017. This report includes the thermal analysis and control of the spacecraft MIST. One of the main systems in a spacecraft is the thermal control system. In order for the payloads and subsystems to withstand the harsh thermal environment in space a thorough thermal analysis is needed. In this project the thermal model has been built and thermal control design of the spacecraft has been started. As a start a preliminary thermal analysis was performed where the spacecraft was approximated as a sphere in order to get some estimates on the temperature in orbit due to the space environment. Furthermore the temperature decrease in eclipse was studied. Since most of the spacecraft will consist of Printed Circuit Boards (PCB) the thermal behavior of PCB has been investigated and as a part of this investigation a thermal vaccum chamber test was performed where the conductance from a PCB through the mounting interface to a metal plate was measured. This report will also guide the reader through the model built and assumptions made. As a part of the thermal control, Multi Layer Insulation (MLI) has been studied and modeled in two di erent ways which have been compared with each other in order to know the level of detail needed for the MLI model. Last but not least the design of the thermal control system has been started where some payloads have been wrapped in MLI and thermal contact conductance coecient has been changed in order to meet the thermal requirements of the payloads and subsystems.

The task of this master's thesis was to design a transformer test bench while focusing on safety and usability. There are several safety risks when working with high voltages, therefore the high demand for safety precautions. A bench was worked upon, and attachments, such as module frames and banana connectors were integrated into the bench. Further, a list of components were modied and installed on the new bench. A new design, using a magnetic non-contact safety interlock switch and an easy-to-apply circuitry, was proposed and implemented. In addition to the implementation, a code in LabVIEW was written in order to handle the measured data from the tests that can be performed on a transformer. Several tests were performed on a single-phase transformer and a three-phase transformer in order to verify the function of the transformer test bench, with respect to the design. Complications emerged due to random additive noise. After some work, the noise was suppressed and the results showed that the equipment worked well with the new design. Finally, a user's manual was written in order to guide the user through the wire connections, tests and the developed software in LabVIEW. / En transformatortestbänk avsedd för laborationer inom forskning och utbildning har utvecklats, där fokus har lagts på säkerhet och användbarhet, eftersom arbete med höga spänningar medför säkerhetsrisker. En bänk modierades för att möjliggöra fastsättning av moduler samt banankontakter. Vidare anskaades elektroniska komponenter, bearbetades och installerades. En design med en magnetisk switch samt lättanvända kretsar föreslogs. Dessutom skrevs en kod i LabVIEW med ett brett användningsområde. Ett 　flertal tester utfördes på en enfastransformator och en trefastransformator med syfte att säkerställa att komponenter- na fungerar väl ihop med den framtagna transformatortestbänken. En del komplikationer uppstod på grund av slumpmässigt, additivt brus. Detta gick dock att undertrycka. Det slutliga resultatet visade att kom- ponenterna fungerade väl ihop med den framtagna transformatortestbänken. Slutligen skrevs en användarmanual med syfte att instruera använda- re av transformatortestbänken beträande kopplingarna, testerna samt mjukvaran som är skriven i LabVIEW.

Security is recently arising as an important issue for the Internet of Things (IoT). Efficient ways to provide secure communication between devices and sensors is crucial for the IoT devices, which are becoming more and more used and spread in a variety of fields. In this context, Elliptic Curve Cryptography (ECC) is considered as a strong candidate to provide security while being able to be functional in an environment with strong requirements and limitations such as wireless sensor networks (WSN). The solutions used need to be efficient for devices that have some important restrictions on memory availability and battery life. In this master thesis we present a lightweight BSD-based implementation of the Elliptic Curve Cryptography (ECC) for the Contiki OS and its evaluation. We show the feasibility of the implementation and use of this cryptography in the IoT by a thorough evaluation of the solution by analyzing the performance using different implementations and optimizations of the used algorithms, and also by evaluating it in a real hardware environment. The evaluation of ECC shows that it can adapt to the upcoming challenges, thanks to the level of security that it provides with a smaller size of keys when compared to other legacy cryptography schemes.