Händelser: Signaler och system, Elektroteknikhttp://www.chalmers.se/sv/om-chalmers/kalendariumAktuella händelser på Chalmers tekniska högskolaFri, 09 Apr 2021 16:09:23 +0200http://www.chalmers.se/sv/om-chalmers/kalendariumhttps://www.chalmers.se/sv/institutioner/e2/kalendarium/Sidor/Disputation-Junfei-Tang.aspxhttps://www.chalmers.se/sv/institutioner/e2/kalendarium/Sidor/Disputation-Junfei-Tang.aspxJunfei Tang, Elektroteknik<p>https://chalmers.zoom.us/j/68624590055</p><p>​Titel på avhandlingen: Design and Control of Electrically Excited Synchronous Machines for Vehicle Applications</p><a href="https://chalmers.zoom.us/j/68624590055">​<span style="background-color:initial">Anslut till seminariet från PC, Mac, Linux, iOS eller Android via Zoom</span>​</a><div><br /><div>The seminar can be accessed through Zoom, and it will open shortly before 10:00. We would kindly ask you to keep the video off and mute the microphone during the seminar. At the end of the session there will be an opportunity to ask questions through Zoom. In case there will be any updates about the event, these will be posted on this website.</div> <div><br /></div> <div>Junfei Tang är doktorand vid forskargruppen Elmaskiner och kraftelektronik</div> <div>Opponent är Professor Mats Alaküla, Faculty of Engineering, Lund University</div> <div>Examinator är bitr Professor Ola Carlson vid forskargruppen Elnät och komponenter</div> <h2 class="chalmersElement-H2">Sammanfattning</h2> <div>Electrically excited synchronous machines (EESMs) are becoming an alternative to permanent magnet synchronous machines (PMSMs) in electric vehicles (EVs). This mainly attributes to the zero usage of rare-earth materials, as well as the ability to achieve high starting torque, the effectiveness to do field weakening and the flexibility to adjust power factor provided by EESMs. Furthermore, in case of converter failure at high speed, safety can be improved by shutting down the field current in EESMs. </div> <div><br /></div> <div>The purpose of this study is to investigate the potential application of EESMs in EVs. To achieve this aim, several topics are covered in this study. These topics are studied to confront the challenges before EESMs could become prevalent and to maximumly use the advantages of EESMs for EV applications. In control strategies, the challenge is to properly adjust the combination of stator and field currents so that high power factor and minimum copper losses can be achieved. To tackle this, control strategies are proposed so that reactive power consumption and total copper losses are minimized. With the proposed strategies, the output power is maximized along the torque-speed envelope and high efficiency in field-weakening is achieved. In dynamic current control, due to the magnetic couplings between field winding and stator winding, a current rise in one winding would induce an electromagnetic force (EMF) in the other. This introduces disturbances in dynamic current control. In this study, a current control algorithm is proposed to cancel the induced EMF and the disturbances are mitigated. In machine design, high starting torque and effective field weakening are expected to be achieved in the same EESM design. To realize this, some criteria need to be satisfied. These criteria are derived and integrated into the design procedure including multi-objective optimizations. A 48 V EESM is prototyped during the study. In experimental verification, a torque density of 10 N·m/L is achieved including cooling jacket. In field excitation, a contactless excitation technology is adopted, which leads to inaccessibility of the field winding. To realize precise control of field current in a closed loop, an estimation method of field current is proposed. Based on the estimation, closed-loop field current control is established. The field current reference is tracked within an error of 2% in experimental verifications. The cost of an EESM drive increases because of the additional converter used for field excitation. A technique is proposed in which the switching harmonics are extracted for field excitation. With this technique, both stator and field windings can be powered using only one inverter. </div> <div><br /></div> <span style="background-color:initial">From all the challenges tackled in this study, it can be concluded that the application of EESMs in EVs is feasible.  ​</span></div>https://www.chalmers.se/sv/institutioner/e2/kalendarium/Sidor/Masterpresentation-Abbas.aspxhttps://www.chalmers.se/sv/institutioner/e2/kalendarium/Sidor/Masterpresentation-Abbas.aspxSaad Abbas Abbasi, MPNET<p>Webseminarium</p><p>​Behavioral modeling of power amplifiers with machine learning on multi carrier and multi band scenarios</p><div>​</div> <div> <p class="MsoNormal"><span lang="EN-US" style="font-family:&quot;segoe ui&quot;, sans-serif"><a href="https://teams.microsoft.com/l/meetup-join/19:meeting_NDIwYmYzOTAtMGY3NS00ZWE1LWJhYmItZmQ2YzNmMjQzZTNi%40thread.v2/0?context=%7b%22Tid%22:%22a13e1e56-894f-4630-8e8f-e8b46617ea67%22%2c%22Oid%22:%22eeecc19a-d326-4c1b-8c99-3f1bc45a1177%22%7d" target="_blank"><span style="font-size:10.5pt;font-family:&quot;segoe ui semibold&quot;, sans-serif">Click here to join the meeting</span></a> </span></p> <br /></div> <div>Examinator: Thomas Eriksson, Inst för elektroteknik</div> <div><br /></div> <h2 class="chalmersElement-H2">Sammanfattning</h2> <div><br /></div> <div>The purpose of this thesis is to explore the possibility of using machine learning (ML) algorithms for the behavioral modeling of power amplifier (PA). This thesis is an extension of the previous masters thesis work [5] which compares the performance of ML methods with memory polynomial (MP), generalized memory polynomial (GMP) and look-up table (LUT) methods for the PA modelling on single carrier and single band scenario. We expand it to multicarrier and multiband scenarios. The performance of MP and GMP as the baseline algorithms are compared with the performance of ML algorithms as neural network (NN), gradient boosting (GB), decision trees (DT) and linear regression (LR) in terms of normalized mean square error (NMSE) and adjacent channel error power ratio (ACEPR). The experiments are done with three different test scenarios for single carrier as a reference case, multi carrier in full band, and multi carrier in separated band/carrier. Experimental results show that NN achieves the best performance in all of the test scenarios except for the separated multi-carrier scenario and GB also gives the best performance in one of the separate multi-carrier scenario but in most scenarios the performance is worse than MP and GMP results. DT gives poor performance at all and finally LR fails to correctly predict the test output signal as expected that the PA modeling can be considered the non-linearity problem. Finally, computational complexity analysis of ML algorithms is given with the corresponding performance results of ML algorithms in this study.<br /><br /></div>https://www.chalmers.se/sv/styrkeomraden/halsa-och-teknik/kalendarium/Sidor/Engineering-Health-2021.aspxhttps://www.chalmers.se/sv/styrkeomraden/halsa-och-teknik/kalendarium/Sidor/Engineering-Health-2021.aspxEngineering Health 2021<p></p><p>​Välkommen till vårt initiativseminarium våren 2021!​ ​​​</p>​<img src="/SiteCollectionImages/Areas%20of%20Advance/Health/Toppbilder/Engineering-Health-2021-750.jpg" alt="" style="margin:5px" /><br /><br /><div>Initiativseminariet Engineering Health har underrubriken <strong>Joining forces in healthcare solutions</strong>. De två dagarna är öppna för alla och kostnadsfria.<br /><br /><span style="background-color:initial"><a href="http://www.chalmers.se/en/areas-of-advance/health/news/Pages/Engineering-Health-2021.aspx">Hela programmet finns nu tillgängligt här​</a>.</span><div><a href="https://ui.ungpd.com/Events/2257cee4-fde6-4cec-ac3c-d2462f0d9b62">Anmäl dig här!​​</a><br /><br /></div> Det två dagar långa eventet är uppdelat i fyra delar:</div> <div><div>• <strong>New technology:</strong> Pushing the boundaries in diagnostics and treatment</div> <div>• <strong>Prevention:</strong> Keep out (of the hospital)!</div> <div>• <strong>Restoring health:</strong> New solutions for rehabilitation</div> <div>• <strong>Modern treatment:</strong> Personalised health- and self-care<br /><br /></div></div> <div>​Vi presenterar stolt vår inspirationstalare <strong>Carolina Klüft</strong>, som kommer att tala om sitt engagemang i Generation Pep och ungas hälsa.<br /></div>https://www.chalmers.se/sv/styrkeomraden/produktion/kalendarium/Sidor/Digitala-tvillingar-för-individualiserad-produktion.aspxhttps://www.chalmers.se/sv/styrkeomraden/produktion/kalendarium/Sidor/Digitala-tvillingar-f%C3%B6r-individualiserad-produktion.aspxDigitala tvillingar för individualiserad produktion<p>Online</p><p>​I den sjätte delen av styrkeområde Produktions seminariesserie handlar det om digitala tvillingar.</p><div><span style="background-color:initial"><br /></span></div> <span style="background-color:initial">Dagens talare är Rikard Söderberg, professor i produkt- och produktionsutveckling, Institutionen för industri- och materialvetenskap.</span><div><b>Innehåll: </b><span style="background-color:initial">Under de senaste decennierna har variationssimulering utvecklats och implementerats i industrin. Huvudsyftet är att stödja tidiga produkt- och produktionsutvecklingsfaser mot “första gången rätt”, höja kvalitén och undvika dyra prototyper och testserier.</span></div> <div>I seminariet visar Rikard Söderberg hur variationssimulering kan användas som digital tvilling för att kontrollera och förbättra kvalitén i löpande produktion.​</div> <div></div> <div><br /></div> <div><b>Datum och tid: </b>15 april 2021, 11: 00-12: 00. Det är ca 30 minuters seminarium med efterföljande frågestund. </div> <div><b>Språk: </b>Engelska</div>https://www.chalmers.se/sv/institutioner/e2/kalendarium/Sidor/Masterpresentation-Daniel-Åkerberg.aspxhttps://www.chalmers.se/sv/institutioner/e2/kalendarium/Sidor/Masterpresentation-Daniel-%C3%85kerberg.aspxDaniel Åkerberg, MPEPO<p>Webseminarium</p><p>​ Development of testbed for EMP radiated susceptibility testing</p><div>​</div> <div><a href="https://chalmers.zoom.us/j/66649473361">Anslut till seminariet via Zoom.</a></div> <div>Lösenord: 718390<br /></div> <div><br /></div> <div>Examinator: Yuriy Serdyuk, Inst för elektroteknik</div> <div>Opponent: Erik Andersson</div> <h2 class="chalmersElement-H2">Sammanfattning</h2> <div><br />In the modern society, complex electronic devices are widely used that, either intentionally or unintentionally, radiate signals imposing a risk of interferences with other electronics. To meet a growing urge for uninterrupted operation of electronic devices and systems, testing for approving sufficient electromagnetic compatibility are essential. Such tests, including radiated susceptibility tests, are described in the globally used military test standard MIL-STD-461G. This project aimed to develop a testbed for radiated susceptibility testing for objects sized up to 1x1x1 m3. The test procedure comprises generation of a high voltage pulse and injection of the pulse into a radiation system for creating a transverse electromagnetic field to which the test object is exposed. For the test to be valid, the electromagnetic pulse should provide the front time of maximum 2.3 ns, full width at half time of maximum 18-28 ns and the electric field amplitude of minimum 50 kV/m.<br />The testbed materiel produced within this project includes a radiation system constituted by a 3 m high transmission line composed by 21 conducting wires arranged in a parallel plate resembling structure, a water resistor to make a matched termination of the transmission line, a pressure vessel including a pulse trigger spark gap and field derivative sensors for measuring both electric displacement field and magnetic flux density. FEM based simulations were performed to verify design parameters of the transmission line and the spark gap. <br />In the experiments, a low inductance, 200 kV rated capacitor bank of 4 nF was charged with a voltage impulse of 900 ns front time originating from a Marx generator. Further, electromagnetic pulses were generated by rapidly discharging the capacitor bank into the transmission line via the pulse trigger spark gap enclosed in the vessel filled with SF6 gas at pressure up to 3 bar. Prominent scattering in the trigger voltage was observed, which probably was caused by impurities in the gas system. Electromagnetic pulses with the front time of 8 ns were successfully generated. The pulse amplitude of 173 kV was obtained, but only occasionally due to issues with external flashovers in the pulse generator. The amplitude of reliably repeatable pulses was 132 kV. Consequently, the electric field requirement of minimum 50 kV/m was not fully fulfilled that was shown by the compilation of the results from the electric field simulations and measured signal attenuation in the transmission line. <br />The analysis of the results suggests the ways for further improvements. Thus, it is found that the testbed premises (the high voltage laboratory with grounded walls, floor and ceiling) implicated undesired waves reflections, which need to be damped. Further, an evaluation of different measurement cables emphasized the need of using properly shielded cables to suppress noise level. Various types of transmission line termination resistors were tested and it was concluded that a water resistor was preferred as it features low inductance and its resistance value could easily be adjusted to make a properly matched termination. In addition, the used field sensors would need to be calibrated to give absolute values of the electric field amplitude. <br /></div>https://www.chalmers.se/sv/styrkeomraden/halsa-och-teknik/kalendarium/Sidor/GRSHE-seminarium-Torbjorn-Lundh.aspxhttps://www.chalmers.se/sv/styrkeomraden/halsa-och-teknik/kalendarium/Sidor/GRSHE-seminarium-Torbjorn-Lundh.aspxSeminarium: Starting something new<p>Zoom</p><p>Om utmaningar och genombrott i samarbeten mellan medicin, matematik och teknik. Detta seminarium arrangeras av  ​Gothenburg Research School of Health Engineering, i samarbete mellan Chalmers och Sahlgrenska akademin/Sahlgrenska Universitetssjukhuset.​</p>​<br /><span style="background-color:initial">Mer inform​ation på <a href="/en/areas-of-advance/health/calendar/Pages/GRSHE-seminar-Torbjorn-Lundh.aspx">den engelska sidan här</a>.</span><span style="background-color:initial">​</span>https://www.chalmers.se/sv/institutioner/e2/kalendarium/Sidor/Masterpresentation-Murali.aspxhttps://www.chalmers.se/sv/institutioner/e2/kalendarium/Sidor/Masterpresentation-Murali.aspxAshwin Kumaar Murali Dharan, MPBME<p>Webseminarium</p><p>​ A pilot study on developing an artificial head for bone conduction devices testing purposes</p><div>​</div> <div><a href="https://chalmers.zoom.us/j/69357263267">Anslut till seminariet via Zoom.</a></div> <div>Lösenord: 513244<br /></div> <div><br /></div> <div>Examinator: Sabine Reinfeldt, Inst för elektroteknik</div> <div>Handledare: Henrik Fyrlund, Cochlear Bone Anchored Solutions AB</div> <div><br /></div> <h2 class="chalmersElement-H2">Sammanfattning</h2> <div><br /></div> <div>Hearing loss is a major health issue throughout the world and reduces the quality of life for people. Various types of hearing implants have been developed to support people with such an impairment. One such type of hearing aid is the bone conduction hearing implants, which facilitate sound transmission to the inner ear via the skull bone, thereby bypassing the outer and middle ears. They are intended for patients with the conductive hearing loss (problems with outer or middle ear), mixed hearing loss (combination of conductive loss and sensorineural loss in cochlea or auditory nerve) and single sided deafness (loss of hearing perception in one of the ears). For research and development purposes in the bone conduction business, there are some subjective measurements involving human subjects for parameters such as mechanical point impedance, transcranial attenuation, skin attenuation and acoustic feedback. These parameter values are relevant during testing, calibration, product development and quality control phases for bone conduction hearing implants.<br />However, involving human subjects for testing is a challenge, as these are patients, who are surgically implanted with hearing implants, which makes the whole process impractical and cumbersome on a long term basis. Hence there exists a need to develop an alternative, which is the objective measurements of the above mentioned parameters. One option among the objective measurements could be testing on cadavers or post-mortem human surrogates. However, these options have their own pitfalls, in the sense that they change in nature after death, leading to variability in results and there are also ethical issues, which makes this an undesirable option. We could accomplish these objective measurements through development of an artificial<br />or synthetic head, which can illicit the same or similar mechanical and acoustic response as a live human subject would.<br />This thesis work, which was done in collaboration with Cochlear Bone Anchored Solutions AB (CBAS), focuses on building an artificial head prototype (which consists of an artificial skull, skin and brain assembled together) to be used for testing the bone conduction hearing implants developed by Cochlear. An extensive literature<br />study was conducted to identify materials which could mimic the mechanical properties of the skull, the skin and the brain. These materials/prototypes have been sourced from various facilities throughout the world and they are assembled at CBAS, Mölnlycke, Sweden.<br />Different brain surrogate materials on spheres were tested and the spheres mechanical point impedance were measured. The obtained results were plotted, compared with the clinical reference and an existing artificial head values. From the results, Permagel was identified as the most suitable brain surrogate material from the test results, which is to be later used on an anatomically correct artificial head for testing all the relevant parameters mentioned before.<br /></div>https://www.chalmers.se/sv/styrkeomraden/produktion/kalendarium/Sidor/Produktion-i-rymden.aspxhttps://www.chalmers.se/sv/styrkeomraden/produktion/kalendarium/Sidor/Produktion-i-rymden.aspxProduktion i rymden<p>online</p><p>Hur massproducerar man för rymden? Kan man tillverka produkter på Mars? Och hur bidrar Chalmers till rymdteknik och forskning? Det är några av de frågor vi kommer att lyfta under temat: Produktion i rymden.​</p><div><span style="background-color:initial">Sverige är en framstående rymdnation, inte minst tack vare vår rymdindustri som till största delen ligger i Västsverige. Chalmers är en viktig part, som har stor bredd av rymdforskning inom olika discipliner, inte minst inom produktion där t ex additiv tillverkning förbättras och anpassas för rymdtillämpningar.</span></div> <div><span style="background-color:initial">Välkommen till en intressant eftermiddag där vi möter forskare och inbjudna gäster från NASA, Rymdstyrelsen med flera.</span></div> <div>Anmälan öppnar snart!</div> <div><span style="background-color:initial"><br /></span> ​</div>https://www.chalmers.se/sv/styrkeomraden/halsa-och-teknik/kalendarium/Sidor/GRSHE-seminarium-Ana-Nordberg.aspxhttps://www.chalmers.se/sv/styrkeomraden/halsa-och-teknik/kalendarium/Sidor/GRSHE-seminarium-Ana-Nordberg.aspxSeminarium: Legal and ethical aspects to consider in medical research and healthcare?<p>Zoom</p><p>Legala och etiska aspekter av medicinsk forskning och sjukvård. Detta seminarium arrangeras av  ​Gothenburg Research School of Health Engineering, i samarbete mellan Chalmers och Sahlgrenska akademin/Sahlgrenska Universitetssjukhuset. ​​​</p>​Mer information på <a href="/en/areas-of-advance/health/calendar/Pages/GRSHE-seminar-Ana-Nordberg.aspx">seminariets engelska sida här</a>.https://www.chalmers.se/sv/styrkeomraden/halsa-och-teknik/kalendarium/Sidor/GRSHE-seminarium-Polesie-och-Heckemann.aspxhttps://www.chalmers.se/sv/styrkeomraden/halsa-och-teknik/kalendarium/Sidor/GRSHE-seminarium-Polesie-och-Heckemann.aspxSeminarium: Artificial intelligence in health care<p>Zoom</p><p>Om potentiella hinder när forskning kring AI ska implementeras i sjukvården. Detta seminarium arrangeras av  ​Gothenburg Research School of Health Engineering, i samarbete mellan Chalmers och Sahlgrenska akademin vid Göteborgs universitet samt Sahlgrenska Universitetssjukhuset.</p>​<br />Mer infor​mation på <a href="/en/areas-of-advance/health/calendar/Pages/GRSHE-seminar-Polesie-and-Heckemann.aspx">den engelska sidan här</a>.https://www.chalmers.se/sv/institutioner/e2/kalendarium/Sidor/International-Conference-on-Phantom-Limb-Pain-SV.aspxhttps://www.chalmers.se/sv/institutioner/e2/kalendarium/Sidor/International-Conference-on-Phantom-Limb-Pain-SV.aspxInternational Conference on Phantom Limb Pain<p>R-huset, Mölndals sjukhus, Mölndal</p><p>​Den första internationella konferensen om fantomsmärta, Phantom Limb Pain, (ICPLP) sammanför framstående experter inom forskning och behandling av fantomsmärtor i ett forum för öppen diskussion om teorier och rön.</p>​<div>​Läs mer <br /></div> <div><a href="/sv/institutioner/e2/nyheter/Sidor/Forsta-forskarkonferensen-om-fantomsmartornas-gata.aspx"><img class="ms-asset-icon ms-rtePosition-4" src="/_layouts/images/ichtm.gif" alt="" />​<span style="background-color:initial">Första forskarkonferensen om fantomsmärtornas gåta <br /></span></a></div> <div><span style="background-color:initial"><br /></span></div> <div><span style="background-color:initial">Mer information och anmälan till konferensen</span></div> <div><a href="http://www.bnl.chalmers.se/wordpress/index.php/icplp-2020/" target="_blank"><img class="ms-asset-icon ms-rtePosition-4" src="/_layouts/images/icgen.gif" alt="" />ICPLP:s webbplats​</a></div> <div><br /></div> <div>Konferensen var ursprungligen planerad att hållas 2020 men har flyttats fram i tiden på grund av coronapandemin.</div> <div><br /></div>