Every electronics product should be electromagnetic compatible and adherence to appropriate standards for commercial success. Solar Bora, situated in Linköping, manufactures off-grid power systems with solar cell systems that deliver a high-power output of 230 VACclean and stable electricity. The energy stored in the batteries must be effectively transferred from DC to AC with the help of an inverter module. The current master’s thesis is about radiated emission testing on the controller printed circuit board which contributes to overall emissions in the inverter. EN-61000-6-3: Generic standards - Emission standards for residential, commercial, and light-industrial environments guide the testing procedure.When there are limited prototype runs and a short time to market, knowing and comprehending how different design factors affect EMC performance is critical. This thesis will look at how different layout design factors impact the converter’s radiated emissions. Radiated emissions testing in the frequency range 30 MHz - 1 GHz are the focus. Based on the findings, appropriate mitigation measures are implemented to minimize radiated emission; Altium Designer used in the new converter layout design. The new converter was put through the same emission test as per standard in the lab to ensure its functioning.

n recent years visible light communication (VLC) has been one of the technologies overgrowing in this competitive world and breaking through the wireless transmission of future mobile communications. This VLC replaces radio frequency (RF), which has several important features like large bandwidth, low cost, unlicensed spectrum. In telecommunications, there is a need for high bandwidth and secure transmission of data through a network. Communication can be done through wired and wireless. Wired communication such as coaxial cable, twisted wire, fiber optics, and wireless are RF, light fidelity (Li-Fi), optical wireless communication(OWC). In our daily lives, we are transferring data from one place to another through a network connection. The network is connected to multiple devices as the network bandwidth provided by VLC is higher than the RF communications. When multiple devices are connected to RF, the latency is high. In the case of VLC, the latency is low. In this research, the light emitting diode (LED) bulbs act as the transmitter(Tx), and the avalanche photodiode (APD) acts as a receiver(Rx). This research mainly focuses on creating a MATLAB simulation environment for a two-room VLC system with given spectral power distributions. We have simulated two rooms with the exact dimensions. The LEDs are placed in opposite positions in each room. LED is placed at the middle top of the ceiling in one room, and a photodiode (PD) is placed on top of the table under the light in the same room. Moreover, in another room, the light is placed on top of the table at the bottom, and PD is placed at the middle top of the ceiling.Moreover, these two rooms are connected to the same network.   The input parameters are taken from the previous studies, but the transmitting power is calculated from the Red-Green-Blue(RGB or White) light spectrum distribution using the OOK modulation technique. We obtained responsivity of APD at a single point and bit error rates(BER) of APD at multi-points inside both the rooms.

Borealis i Stenungsund är Sveriges enda polyetentillverkare och deras krackeranläggning är en av de mest flexibla i Europa. Då anläggningen är i ständig utveckling behövs nya verktyg för att modellera elanläggningarna som kan ge en helhetsbild. Syftet med rapporten är att undersöka hur väl det fungerar att implementera Borealis existerande lågspänningsställverk i programmet Febdok, som används för att dimensionera kablar och skydd i elanläggningar enligt svensk standard. För att undersöka detta tas modeller fram för två olika lågspänningsställverk i Borealis anläggning fram för att utvärdera programmet. Rapporten tar fram tre generella beräkningsexempel i Febdok och utför manuella beräkningar för att kontrollera resultaten i programmet. Exemplen beskriver olika driftlägen för ett enkelt lågspänningsnät i normal drift, drift med UPS och drift med reservgenerator. Resultaten av de manuella beräkningar som utförts ligger nära motsvarande värde i Febdok. Metoden för beräkningarna diskuteras i varje exempel utifrån felkällor och de förenklingar som gjorts. Utifrån beräkningsexemplen utförs modelleringen av ställverken i Febdok. Detaljer har utelämnats av sekretesskäl och delar som är svåra att modellera har lyfts fram. Exempelvis beskrivs hur reläskydd kan modelleras som effektbrytare och hur felaktig kabelförläggning kan hanteras. Problematiken med modelleringen diskuteras utifrån de specifika ställverken men också ur ett generellt perspektiv. Rapporten visar att det går att skapa en modell av ett befintligt lågspänningsställverk i Febdok om vissa metoder används för att kringgå säkerhetsfunktioner och kontrollfunktioner i programmet. Dessutom beskrivs hur värden på strömmar och spänningar i Febdok kan reproduceras med hjälp av manuella beräkningar. Exemplen som används beskriver vilka parametrar som har använts för att räkna fram belastningsströmmar, spänningsfall och felströmmar samt en diskussion kring avvikelser görs också när resultaten jämförs. Slutligen beskrivs ett antal förbättringsförslag som förenklar modellering av existerande anläggningar. / Borealis in Stenungsund is Sweden's only polyethylene manufacturer and their cracker plant is one of the most flexible in Europe. As the plant is in constant development, new tools are needed to model the electrical systems that can provide an overall picture. The purpose of the report is to investigate how well it works to implement Borealis existing low voltage substation in the Febdok program, which is used to dimension cables and protection devices in electrical installations according to Swedish standards. To investigate this, models are produced for two different low-voltage substations at Borealis facility in order to evaluate the program. The report produces three general modelling examples in Febdok and performs manual calculations to validate the results in the program. The examples describe different operating modes for a simple low-voltage network in normal operation, operation with UPS and operation with a backup generator. Results of the manual calculations performed are close to the corresponding values given by Febdok. Calculation methods and resulting accuracy are discussed in each example based on sources of error and the simplifications made. Based on the general modelling examples, the modeling of the selected low-voltage substations is performed in Febdok. Details have been omitted for reasons of confidentiality and parts that are difficult to model have been described in detail. Problems with the modeling are discussed based on the specific switchgear but also from a general perspective. The report shows that it is possible to create a model of an existing low-voltage substation in Febdok if certain methods are used to circumvent safety functions and control functions in the program. In addition, it is described how values of currents and voltages in Febdok can be reproduced using manual calculations. The examples used describe which parameters have been used to calculate load currents, voltage drop, fault currents and a discussion of deviations is also made when the results are compared. Finally, several proposals for improvements are described that simplify modeling of existing facilities.

No description available.

Project Ngulia is a public-private partnership that aims at developing innovative cost-efficient technical solutions in Ngulia sanctuary, Kenya. The technologies assist KenyaWildlife Service (KWS) with improving the security of rhinoceros. So far they have, amongothers, developed a dashboard showing the status of the sanctuary. This thesis attempts toinstall a LoRaWAN network system containing a server and a gateway, and to develop anappurtenant end-device prototype sampling the pH, conductivity, and temperature of thewater holes in the sanctuary. The plan is for Project Ngulia to, later on, include the samplesfrom the end-device in the dashboard using the LoRaWAN network system. In addition,the thesis attempts to evaluate the advantages and disadvantages of using LoRaWAN inthis use case by both literature studies and by tests during the implementation.The total system was developed according to a model inspired by the NASA engi-neering design process, an iteration of six steps;Identify criteria and constraints,identify theproblem,explore hardware and possibilities,select an approach,build a prototypeandevaluate. TheLoRaWAN network system and the water sample prototype was in every iteration devel-oped on the basis of the design goals of robustness and power consumption.The final prototype was built upon an Arduino Pro Mini 3.3V 8MHz, the LoRa ra-dio transceiver SX1276 and the open source LoRaWAN library calledarduino-lmic version1.5.0+arduino-2. The gateway, however, was build on a Raspberry Pi 3 model B, the opensource library namedpacket ́forwarderand an iC880A concentrator which contains theSX1301 LoRa radio transceiver. The server used was the LoRaServer software. An ad-vantage of LoRaWAN is that the range of the LoRa radio signal seems to cover the waterholes of interest in Ngulia sanctuary quite good with five gateways. Another is that onegateway can handle up to 100 end-devices broadcasting data every 20 minutes or less. Adisadvantage, on the other hand, is the memory occupation the LoRaWAN protocol occu-pies in the end-device, limiting the number of sensors to be connected to each end-device.

This thesis is the final module of the Master's program in Electronics Design at Halmstad University. The Master Thesis work is a part of an ongoing development of Halmstad University's reverberation chamber (RC), which is aimed at frequencies in the low GHz range. The development process has been passing in several phases. One phase is to design a mechanical stirrer system which was done by the work presented in another thesis work. The current phase, which is done by this thesis work, is to investigate electromagnetic field uniformity and isotropy while using tuned-mode (stepped stirrer). The frequency 2.4 GHz was chosen because, from one hand, it fits the capability of the assigned equipment for this thesis (spectrum analyzer, signal generator, antennas). On the other hand, it is the operating frequency of a wide range of WIFI and BlueTooth devices that need to be tested inside the RC to comply with the Electromagnetic Compatibility (EMC) standards. The measurement results verified, to a reasonable extent, the field uniformity and isotropy. The standard deviation of all measurements, taken from different eight positions with three different orientations of the receiving antenna, was 1.5dB. It is less than 3dB fulfilling the IEC 61000-4-21standards for frequencies above 400MGHz. Moreover, a quality factor degradation test was conducted, showing a 3.5 dB reduction of the received power when the chamber was loaded by organic material. The received power, while sweeping the bandwidth 800MHz-1.5GHz, was measured. These results indicate that at the resonance frequencies of the chamber, the received power is higher than that at non-resonance frequencies.

The Internet of things (IoT) is a disruptive innovation which has shown the potential to change the way we live our lives. At the core of the IoT eco systems are the wireless sensor nodes. These are responsible for the sensing of the target environment parameters or situations and communication of such to the desired destinations. For this communication to happen, a good performing antenna is required. This project explores the design of an on-PCB inverted-F antenna for a wireless sensor node. The Literature review and insight into wireless sensor nodes and antenna design are conducted. The designed antenna is stimulated using ADS simulation software and the performance analysis presented. Design description of a wireless sensor node is also made, which includesthe high frequency PCB layout design for the sensor node. The antenna and PCB are both fabricated in the lab, while various antenna performance measurements and evaluation are done. The designed antenna showed good S11 parameter of -43dB on simulation and -20dB when fabricated.

A power supply unit with very low standby losses has been constructed. A reference design from Texas Instrument was used as a comparison and starting point. A choice between optimizing the existing reference design or creating a new power supply was made. The losses in the reference design was located to be due to high switching frequency. This also led to losses in the snubber circuit. Because the reference design has an inefficient external start-up circuit and does not allow load dependent switching frequency without an complicated modification, a new power supply was decided to be constructed. The fly- back controller used was the integrated circuit UCC28730, which has a built-in start-up circuit and a load dependent switching frequency function. To implement faster commu- nication between the output and the flyback controller the integrated circuit UCC24650 was added to the design. This allows the UCC24650 to send wake-up signals when a volt- age droop is detected on the secondary side. The new power supply has a built-in under voltage protection to protect the batteries which is the power source. Although the new power supply seems to regulate the desired output voltage during no load, it does seem to have issues with faults during both no load and load. / Ett nätaggregat med väldigt låg tomgångsförbrukning har byggts. En referensdesign från Texas Instrument användes som jämförelse och startpunkt. Ett val mellan optimering av den befintliga referensdesignen eller att skapa en ny design gjordes. Förlusterna i referensdesignen lokaliserades att vara på grund av hög switchfrekvens. Detta ledde även till att förluster i dämpningarna i snubberkretsen. Eftersom referensdesignen har en ineffektiv extern uppstartningskrets och inte tillåter att gå ner i switchfrekvens beroende på last utan en komplicerad modifikation, beslöts att ett nytt nätaggregat skulle konstrueras. Som spänningsregulator användes integrerade kretsen UCC28730, vilket har en inbyggd uppstartningskrets och en funktion som möjliggör lastberoende switchfrekvens. För att implementera snabbare kommunikation mellan utgången och regulatorn lades även integrerade kretsen UCC24650 till i designen. Detta möjliggör att UCC24650 kan skicka uppvakningssignaler när ett snabbt spänningsfall detekteras på sekundärsidan. Det nya nätaggregatet har ett inbyggt underspänningsskydd för att skydda spänningskällan, vilket är ett batteri. Även fast nätaggregatet reglerar önskad spänning på utgången vid ingen last, visar den sig ha problem med fellägen både med och utan last på utgången.

An autonomous lawn mowing robot moves around randomly within an area enclosed by a magnetic wire and makes decision based on sensor information. To ensure human and animal safety it is essential that the robotic lawn mower can detect and stop if, for instance, it is being lifted by a human. This thesis takes a look at how on-board sensors could be used to detect a few critical events, here called fault cases. Data such as acceleration, angular velocity and motor currents are recorded and then used to develop three methods for detection briefly de-scribed below. The Odometry method uses constraints on valid movement of the robotic lawnmower and a fault case is detected if estimated velocity in global coordinates violates these constraints. The pitch angle relationship estimates the relation between electrical currents needed to drive the robotic lawn mower at a certain speed in certain pitch angle. When the electrical currents corresponding to a certain pitch angle according to the relation deviates from measured currents a fault case would be detected. The frequency method is based on the idea that disturbances on signals caused by uneven ground should decrease when the robotic lawn mower is lifted or held. The method would then detect this damping of disturbances by examining frequency content. The best method is the pitch angle relationship while the other two proposed methods have potential but would need higher sampling frequencies and additional signals to fully perform satisfactorily. With additional information such as position of the robotic lawn mower the estimation of the global velocities could be significantly improved which in turn would improve the odometry method and serve as a complement to the current pitch angle relation. The frequency methods would also be valid if the sampling frequencies were much higher, some-thing that might not be as cost efficient as needed to make the method profitable.

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.