Elektroteknik (E2) // Electrical Engineering (E2)

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https://odr.chalmers.se/handle/20.500.12380/12

Arbetar med hållbara och smarta lösningar på samhällsutmaningar, såsom energieffektivitet och elektrifiering inom områden från transport- och produktionssystem till kommunikationslösningar och medicinteknik.

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För forskning och forskningspublikationer, se https://research.chalmers.se/organisation/elektroteknik/

At the department of Electrical Engineering research and education are performed in the areas of Communication and Antenna systems, Systems and Control, Signal processing and Biomedical engineering, and Electric Power Engineering.

We work with challenges for a sustainable future in society of today, for example in the growing demands concerning efficient systems for communications and electrification. Our knowledge is of use everywhere where there is advanced technology with integrated electronics, no matter if it involves electricity, electrical signals, optical signals or microwaves.

Studying at the Department of Electrical Engineering at Chalmers

For research and research output, please visit https://research.chalmers.se/en/organization/electrical-engineering/

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Visar 1 - 20 av 209

3D modelling and finite element analysis of three phase transformer with integrated inductors in COMSOL Multiphysics
(2020) Choudhary, Kunal; Chalmers tekniska högskola / Institutionen för elektroteknik; Serdyuk, Yuriy; Serdyuk, Yuriy
600 V DC-DC converter for battery charger investigation
(2020) Rajendran, Udhayaraj; Krishnan, Ganapathy Nathan; Chalmers tekniska högskola / Institutionen för elektroteknik; Thiringer, Torbjörn; Thiringer, Torbjörn
A comparison of modulation techniques and motor performance evaluation
(2018) He, Yangdi; Chalmers tekniska högskola / Institutionen för elektroteknik; Chalmers University of Technology / Department of Electrical Engineering
A Model for Simulating FCR Prequalification Tests for Kaplan Turbines
(2024) Eriksson, Eddie; Chalmers tekniska högskola / Institutionen för elektroteknik; Chen, Peiyuan; Ekstrand, Christian
Abstract A Kaplan turbine was modeled in Simulink with the purpose of simulating prequalification tests for Frequency Containment Reserve (FCR) provision, based on technical requirements for FCR introduced in 2023. The model did not successfully predict fulfillment of steady-state requirements, and was too optimistic in its prediction of fulfillment of dynamic requirements. However, all tests predicted to fail also failed in real-world tests, indicating a potential use case for ruling out Kaplan turbines not suitable for FCR provision. A sensitivity analysis showed that simulation results were mostly unaffected by runner servo parameters, indicating a flaw in the model. Compensation with a first order low-pass filter significantly improved the accuracy of simulated dynamics. However, several model parameters, including the time constant for the low-pass filter, needed real-world tests for estimation. This reduced the likelihood of achieving high simulation accuracy ahead of conducting real prequalification tests. Using the simulated prequalification tests, methods for improving performance were explored. Both tuning the FCR controllers and the servos controlling guide vanes and runner blades were shown to improve dynamic performance, but tuning the servos improved the stability margins more. An approach to active power feedback was introduced and resulted in perfect fulfillment of the steady-state requirements. The dynamic performance requirements were not affected much, but the stability margins were severely worsened due to larger control movements at higher frequencies. The results suggested that fulfilling all technical requirements for FCR will be very challenging for Kaplan turbines. However, with increased market participation from other sources, this will likely not lead to insufficient FCR capacity in the near future.
Active distribution networks and their impact on the transmission system
(2022) Andersson, Ludvig; Chalmers tekniska högskola / Institutionen för elektroteknik; Chen, Peiyuan; Chen, Peiyuan
Active Thermal Control of Power Semiconductor for High Power Electric Drive Applications
(2024) Yesgat, Amare; Chalmers tekniska högskola / Institutionen för elektroteknik; Liu, Yujing; Sharma, Nimananda
Abstract Electric vehicle applications, driven by the need for space and mass savings, increasingly demand high-power density inverters. However, this reduction in mass has led to a decrease in thermal capacity, badly exposing power emiconductors to larger temperature swings and thermal cyclic stress. The vulnerability of wire bonds and chip solder in the power semiconductor to failure due to thermal cycling necessitates a solution. This solution, actively controlling the junction temperature during operation, is the focus of this research and is referred to as active thermal control techniques (ATC). Different active thermal control strategies are explored in the literature via manipulation of losses or heat dissipation and they are discussed in this work. Some of the methods require specific hardware, such as specialized gate drivers. The control of junction temperature without any extra hardware can be achieved by controlling the PWM frequency, load current, and modulation methods. However, controlling load current requires implementing an online current reference estimation. Additionally, changing the modulation method would increase control complexity. Therefore, this work investigates active junction temperature control by varying the PWM frequency. The junction temperature is controlled using a hysteresis band-type controller with some modifications. The influence of the control band and average junction temperature calculation on the inverter’s control effectiveness, prolonged lifetime, and improved efficiency is investigated. The inverter’s losses are calculated analytically, and the inverter is implemented together with a heavy-duty truck and machine model in simulations. Drive cycle-based analysis is combined together with rain flow counting and a lifetime model to estimate the influence of the controller on the devices’ lifetime. Simulation results show that the active control of the junction temperature can result in more than 246% increase in lifetime and simultaneously increase efficiency by 0.30%.
Aging models and adaptive SOC estimation for lithium ion batteries
(2018) Maheshwar, Shivadeep; Zhou, Yuwei; Chalmers tekniska högskola / Institutionen för elektroteknik; Chalmers University of Technology / Department of Electrical Engineering
An equivalent circuit model for swelling in Prismatic Lithium-ion cells
(2023) Gingsjö, Erik; Harish , Poshith; Chalmers tekniska högskola / Institutionen för elektroteknik; Thiringer, Torbjörn; Thiringer, Torbjörn
Abstract In this thesis, the expansion behavior of a Prismatic Lithium-ion cell is investigated via its external pressure changes. Experiments were done for 0% to 100% state-of-charge for both charge and discharge at various charging rates from 0.05C to 1.2C. An equivalent circuit with a single resistance was used to model the pressure behavior during charging, where the modeled resistance can be understood as a mechanical resistance of the cell casing to expand. It was shown to exhibit a clear trend for charging rate as well as state-of-charge, with values becoming bigger with both increasing charging rate and state-of-charge up to 0.5C. The model was evaluated for 0.3C with the absolute relative error between the modeled and experimental result being around 1% after 5% to 100% state-of-charge. Data from two research articles with similar pressure change experiments were used to validate the model. The first, [1], used charging rates comparable to those used in this thesis, and the other, [2], used charging rates above 1C. For the former, the modeled resistance values showed similar trends as presented here. For the latter however, the resistance values instead decreased with both state-of- charge and increasing charging rate, which was assumed to be due to lithium plating at higher state-of-charge at the higher charging rates as well as due to thermal effects.
An induction machine vs a standard NdFeB magnet machine
(2019) Bergman, Sebastian; Karlsson, Anders; Chalmers tekniska högskola / Institutionen för elektroteknik; Chalmers University of Technology / Department of Electrical Engineering
An off-grid energy harvesting system for radar equipment
(2019) Blomkvist, Niklas; Loftman, Victor; Chalmers tekniska högskola / Institutionen för elektroteknik; Chalmers University of Technology / Department of Electrical Engineering
Analysis and Improvement of Traction Motor Insulation Systems Exposed to High Switching Frequency Converters
(2021) Alhalak, Mohammed Numair; Chalmers tekniska högskola / Institutionen för elektroteknik; Liu, Yujing; Liu, Yujing
Analysis of asymmetrical features of an electric machine
(2018) Zahangir, Tamanna; Chalmers tekniska högskola / Institutionen för elektroteknik; Chalmers University of Technology / Department of Electrical Engineering
Analysis of Multi-level Inverters for Electric Vehicle Application
(2023) Seshadri, Manoj Krishna; Kanipakam, Vishal; Chalmers tekniska högskola / Institutionen för elektroteknik; Thiringer, Torbjörn
Abstract Traditional two-level inverters are used for electric vehicles on the market today. But, in recent years there is a growing interest in multi-level inverters to be used as the propulsion inverter in electric vehicles. So, this thesis work analyzes the performance of a multi-level inverter of different topologies as a traction inverter and a comparison is made with a traditional two-level inverter. Using a multi-level inverter, multiple levels of the output voltage can be obtained which helps in the reduction of losses and also THD. The implementation and analysis of this work are mostly carried out in PLECS software where different topologies of the multi-level inverter are modeled, simulated and the comparison between the different topologies is made in various aspects such as losses, THD, and also the DC link ripple from the capacitors. The thermal analysis is also done as the inverter models are designed considering the thermal properties of the power module. Finally, a comparison of the different topologies is made using two different switches. One uses the SiC switch and the other uses the GaN switch. In this thesis, a two-level inverter and a multi-level inverter of three levels are in vestigated. In a multi-level inverter, four different topologies (i.e., Neutral point clamped inverter, T-type neutral point clamped inverter, Flying capacitor inverter, and Cascaded H-bridge inverter) are modeled, simulated, and analyzed. Two differ ent switching strategies (i.e., Sine wave PWM and Space vector PWM) are imple mented for the inverter models. But for the multi-level inverter models, phase-shifted sine wave PWM is used. As the number of levels increases, the complexity of the modulation technique, cost, and size of the inverter increases. So, when it comes to selecting an inverter, it is a trade-off between all the above parameters.
Analysis of the Propulsion System of an Electric Aircraft
(2023) Smita, Smita; Kollara Pradeep, Chandrima; Chalmers tekniska högskola / Institutionen för elektroteknik; Lundberg, Stefan; Hellsing, Johan; Mingardo, Giacomo
Abstract This thesis focuses on the design and development of control laws, specially crafted for the propulsion system of the ES-30 aircraft, a creation of Heart Aerospace AB. The ES-30 distinguishes itself as a hybrid electric aircraft, designed for regional travel and outfitted to accommodate 30 passengers. This study unfolds the intricate relationship between the propulsion system and the electrical counterparts, outlining the control laws and the effective functioning of this aircraft. The control function is a network that feeds on the thrust request and air data as its inputs and provides RPM and pitch angle as outputs. This strategic combination is designed to deliver the requested thrust while concurrently maximizing the efficiency of the propulsion system. This idea is taken one step further by accounting for electrical losses that pervade through the propulsion system. These losses are primarily attributed to motor and inverter losses, which vary across different operational phases and time duration. They are integrated into the system-wide considerations to determine the final propeller pitch and motor RPM. Such a holistic approach guarantees a comprehensive understanding of the system’s functioning and the implementation of the most efficient control laws. From our analysis, it has been determined that the optimal RPM - pitch combinations for the Take off, Climb and Cruise flight phases are 1750 rpm and 20.3°, 1650 rpm and 29.15°, 1350 rpm and 31.7°respectively. These combinations offer optimal efficiency during the associated flight phases, a conclusion derived from thorough analysis. The average efficiency of the flight across the Take off, climb and cruise phases for when optimizing for the the propeller efficiency alone was noted to be 82.43 % and compared to 82.49 % when optimizing for the entire propulsion system efficiency. It was also observed that the propeller’s and the entire propulsion system’s optimum operating point is at the same RPM for flight phases with higher thrust demand - Take Off and Climb, while they are different for the phases with lower thrust demand, Cruise. Since the aircraft is in Cruise for the longest time, it makes a difference in the performance of the aircraft.
Analyzing the simplified model of the DFIG wind turbine under short circuit faults
(2018) Heidarzad Pahlaviani, Kasra; Chalmers tekniska högskola / Institutionen för elektroteknik; Chalmers University of Technology / Department of Electrical Engineering
Battery aging and battery modelling
(2018) Syed, Abdul Sattar; Otac, Nevzat; Chalmers tekniska högskola / Institutionen för elektroteknik; Chalmers University of Technology / Department of Electrical Engineering
Battery cell electro-thermal modeling and cooling system design
(2018) Sun, Qian; Tang, Chengjun; Chalmers tekniska högskola / Institutionen för elektroteknik; Chalmers University of Technology / Department of Electrical Engineering
Battery Electric Vehicle with a Fuel Cell Stack
(2019) Wang, Shaohang; Xu, Yiwen; Chalmers tekniska högskola / Institutionen för elektroteknik; Chalmers University of Technology / Department of Electrical Engineering
In this thesis project, a complete fuel cell system submodel, including a fuel cell stack, supplying system, and water management system was modelled. One Fuel Cell Plug-in Hybrid Electric Vehicle (FC-PHEV) and one Fuel Cell Hybrid Electric Vehicle (FC-HEV) model, as well as different components and control strategies, were also implemented in the GT-Suite software to simulate the hydrogen consumption under various driving cycles and scenarios. Furthermore, a cost analysis model is also developed to determine the optimal battery size for the FC-PHEV. Finally, a cost comparison among FC-PHEV, FC-HEV, and Battery Electric Vehicle (BEV)was made based on current data available from the U.S market. The Fuel Cell-PHEV model and the Fuel Cell-HEV model are validated against the WLTC and NEDC driving cycles. The functionality of the main control units is also evaluated. The simulation results show that: For the Fuel Cell-PHEV, the combined hydrogen consumption is 0.29 kg/100 km for NEDC, and 0.34 kg/100 km for WLTC. For the Fuel Cell-HEV, the hydrogen consumption is 0.68 kg/100 km for NEDC, and 0.82 kg/100 km for WLTC. The results of the initial cost comparison of energy source, based on current data show the ranking from the cheapest to the most expensive is FC-HEV, FC-PHEV, and BEV. The ranking of the total cost of ownership, including running cost from the cheapest to the most expensive is FC-PHEV, BEV, and FC-HEV. Overall, the Fuel Cell Plug-in Hybrid Electric Vehicle could be the best choice based on the current data.
Battery electric vehicle with a fuel cell stack
(2019) Wang, Shaohang; Xu, Yiwen; Chalmers tekniska högskola / Institutionen för elektroteknik; Chalmers University of Technology / Department of Electrical Engineering
Battery Energy Storage System for Grid Support and Charging of Electric Ships
(2021) Sabbouh, Mohammad; Persson, Arvid; Chalmers tekniska högskola / Institutionen för elektroteknik; Ehnberg, Jimmy; Ehnberg, Jimmy

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