This thesis studies the options of using PCB embedding bare die power MOSFET and new packaging of MOSFET to increase the power density in a PCB. This is to decrease the winding losses in an isolated DC/DC converter which, according to "Flex Power Modules", can be done by improving the interleaving between the layers of the transformer and/or decreasing the AC loop. To test the MOSFET packaging two layout are made from a reference PCB, one using embedded MOSFET and the other using the new packaging. The leakage induction and winding losses are simulated and if they are lower compared to the reference PCB prototypes are manufactured. The simulated result is that PCB embedded MOSFET decrease the leakage induction but the winding loss is higher. With the new packaging the leakage induction is higher and the winding loss has linear characteristics. Only the PCB with the new MOSFET packaging is made because the MOSFET die gate pad is too small for the PCB manufacturer to make a via connection to it. The PCB is tested that it operates as a DC/DC converter with a 40-60 V input and a 12 V output. The PCB is put on a test board in a wind-tunnel to test its characteristics under different wind speeds, input voltage and loads. The result is that the PCB has a higher efficiency than the reference PCB but it has worse thermal resistance. Further development of the design needs to be made to improve the thermal resistance. Using new packaging is a way to continue the development of power converter with lower efficiency but embedding MOSFET needs a less complicated manufacturing process before there is any widespread usage.

No description available.

The objective of this thesis was to investigate if an optical fiber sensing method with the use of two overlapping fiber Bragg gratings to measure Lamb wave $S_0$ modes in a steel plate, and how it would compare to traditional PZT transducers. A solution was proposed where the use of an optical fiber sensing system was built and took advantage of the strain dependence of a fiber Bragg grating mounted to a steel plate. Together with an overlapping reference fiber Bragg grating, the system can translate strain to light intensity. A method of controlling the Bragg wavelength of the reference fiber Bragg grating to optimize the overlap between the two fiber Bragg gratings, enabling the system to compensate for drift in the sensing fiber Bragg grating. Testing of the system was performed and yielded promising results, being able to measure the Lamb wave signal from the steel plate. The system showed some sensitivity limitations and signal to noise ratio, as well as the software created to compensate for the drift. With the improvement proposed for further work with the system in terms of improving the system's sensitivity, signal to noise ratio and drift control should make the system able to perform at levels as traditional PZT transducers.

The proliferation of Electric Vehicles (EVs) poses new challenges for the Distribution System Operator (DSO). For example, the rectifiers that are used for charging EV batteries could significantly influence Power Quality (PQ), in terms of harmonic distortion. The emissions from individual EV, are well regulated by current harmonic emission standards. But what the aggregation of multiple EV loads will look like is still uncertain and the research being made in this area is still in its early stage.  The DSO responsibilities include ensuring grid code compliance confirmed by PQ metering.  In general, 10 minute RMS values are sufficient. However, the large scale integration of non-linear loads, like EVs, could lead to new dynamic phenomena, possibly lost in the process of time aggregation. In this thesis PQ and, in more detail, the concept of harmonics, and how this is related to EVs, is presented. A current-harmonic load model using power exponential functions and built from actual measurement data during the individual charging of four different fully electric vehicles was constructed. The model was based on individual emitted current harmonics as a function of state of charge (SOC), and was used to deterministically simulate the simultaneous charging of six vehicles fed from the same bus. The aggregation of current harmonics up to the 11th was simulated while randomizing battery SOC, the start of charging, and the kind of vehicle. Additionally, an investigation of the impact on aggregation in time was conducted. The analysis clearly shows the importance of phase angle information, its correlation to SOC, and how the aggregation of EV loads is influenced by these factors. The analysis also shows that 10 minute RMS aggregation could lead to significant deviations from the “actual” (200ms) data.  This indicates that 10 minute value monitoring could lead to information losses.

The ability to reliably connect electrical cables is important in many applications. A poor connection can become a fire hazard, so it is important that cables are always appropriately connected. This thesis investigates methods for monitoring of a machine that presses cable connectors onto cables. Using sensor data from the machine, would it be possible to create an algorithm that can automatically identify the cable and connector and thus make decisions on how a connector should be pressed for successful attachment? Furthermore, would it be possible to create an anomaly detection algorithm that is able to detect whether a connector has been incorrectly pressed by the end user? If these two questions can be addressed, the solutions would minimise the likelihood of errors, and enable detection of errors that anyway do arise. In this thesis, it is shown that the k-Nearest Neighbour (kNN) algorithm and Long Short-Term Memory (LSTM) network are both successful in classification of connectors and cables, both performing with 100% accuracy on the test set. The LSTM is the more promising alternative in terms of convergence and speed, being 28 times faster as well as requiring less memory. The distance-based methods and an autoencoder are investigated for the anomaly detection task. Data corresponding to a wide variety of possible incorrect kinds of usage of the tool were collected. The best anomaly detector detects 92% of incorrect cases of varying degrees of difficulty, a number which was higher than expected. On the tasks investigated, the performance of the neural networks are equal to or higher than the performance of the alternative methods.

This thesis relates to the design and implementation of a Gysel power combiner consisting of two input ports. The design is implemented using discrete (lumped) components over the conventional transmission line architecture and operates at 100 MHz. Because of the high power requirements for the power combiner, special attention is given to the power handling capabilities of the lumped elements and the other components involved. Simulations of an S-parameter of Gysel power combiner are performed using the Advanced Design System (ADS) from Keysight Technologies. The final design of two-way Gysel power combiner using PCB toroidal inductor was implemented, simulated and optimized at centre frequency of 100 MHz. Satisfactory results were obtained in terms of Insertion loss, Return loss and Port Isolation.

In this thesis, a wireless module in form of a portable peripheral printed circuit board that can connect to a master device, periodically sending values from a sensor, has been developed to the company Biotage. A literature study has been made on antennas and PCB-design for high frequency applications and a prototype has been designed through CAD software. This thesis handles the design process behind the module which consists of choosing suitable components, measurements/matching of an antenna and design of a suitable rechargeable power supply module. The prototype resulted in a portable, fully wireless device with a long expected battery life with the help of Bluetooth Low Energy technology and low power usage components.

I arbetet som har utförts i samarbete med företaget Kalmarglobal undersöks om tunga truckar kan drivas med eldrift istället för diesel. Dynamiska laddning undersöks vilket innebär att fordonet ska kunna laddas medan det rör sig. Induktiv laddning ställs mot konduktiv laddning. Med målet att göra batteriernas kapacitet så liten som möjligt jämförs dynamisk och statisk laddning. Rapporten avslutas med en diskussion om olika scenarion vad gäller batteristorlek och effekter.

This report presents a project that has been made to present the design of a planar transformer as a part of a series loaded resonant DC/DC converter in a power unit. The design is based on an existing transformer that is not planar and so the characteristics of the transformer is translated into a planar version. A multilayer printed circuit board (PCB) design was made to fit a chosen magnetic ferrite core that was chosen based on the magnetic characteristics of the old core. Calculations were made for the loss of both core and windings and the final results show that it is possible to design a planar transformer from a traditional transformer.

Suitable locations for marine current power generation were scouted. The specific turbines considered in this project are vertical axis turbines and require an water velocity of 0.8 m/s to start and has a system efficiency of 20%. In the beginning of the project focus was directed towards areas along Florida's coastal line with high water velocities tapping into the Gulf Stream. Data found the velocities did not meet the water speed requirements. Following this observation, it was decided to discontinue further research in the Florida region and divert the attention towards waters in Alaska. There current velocities were found to be significantly higher. Because velocities vary over time marine current power is not relevant in Alaska, but rather the closely related technology tidal power. Two areas in Alaska distinguished themselves, Cook Inlet and Aleutian Islands.Potential power and annual energy extraction were estimated for turbine stations at each site. A battery energy storage system was implemented to counteract varying water velocities. The most promising site could steadily deliver 269 kW and an annual energy production of 2.44 GWh per turbine.