Past seminars at IEA in 2014

Past seminars in 2021, 2020, 2019, 2018, 2017, 2016, 2015, 2014, 2013, 2012, 2011, 2010, 2009, 2008, 2007, 2006, 2005, 2004, 2003, 2002, 2001, 2000, 1999, 1998

Abstract:
This master thesis was carried out at Lund University in collaboration with the European Spallation Source (ESS). It brings up the question of whether it's possible to find an optimal solution for complex electric power electronic topologies, using a well formulated global optimization methodology. The commercially available software tool MATLAB was adopted for these studies, including its own toolbox for optimization. These tools and associated solvers will be described for the optimal design of two different problems:- a power inductor and a multilevel DC/DC power converter. In both cases, the objective function consists of the sum of the capital costs (price of the systems in question) and of the long term operating costs (power losses and maintenance cots). A set of constraints to which the design should comply with is also defined for each case and these will comprise parameters like maximum volume of the system, minimal output performance (value of inductance, maximal saturation field density, maximal current density for the first example or output voltage ripple, volume for the second example), etc. The methodology consists of five steps, the first one is to describe the problem to be optimized. In the second step all the data and information needed to give an accurate view of the problem is to be collected. The third step contains a description of the problem with an objective function that should be optimized. The fourth step corresponds to the definition of the boundaries or constraints. Finally, the fifth step consists on the evaluation of the obtained results.

Supervisor: Carlos Martins, ESS and IEA.

Examiner: Mats Alaküla, IEA.

Description:
This master thesis is about building and testing of a new idea for how to provide cars with power directly from the road by a conductive connection. The electric road system is analyzed with regard to dynamic thermal and electromagnetic properties including lighting protection. The thermal model includes solar radiation and variations in traffic intensity. Both FEM models and lumped parameter models are used.

Supervisor: Lars Lindgren, IEA

Examiner: Mats Alaküla, IEA

Description:
This master thesis is about building and testing of a new idea for how to provide cars with power directly from the road by a conductive connection. For safety reasons this requires switching on and off the power to small sections as the vehicles passes by. A very compact 600 V, 400 A, IGBT switch prototype with driver and short-circuit protection are designed and built. The design are analyzed and tested for both thermal and electric properties. Furthermore a compact specialized high current connector has been built and tested.

Supervisor: Lars Lindgren, IEA

Examiner: Mats Alaküla, IEA

Opponents: Christopher Dahlin.

Abstract:
Material science has become an important research area in order to fulfill today's requirements on lighter, cheaper and more sustainable materials. The European spallation source is a research center based on the world's most powerful neutron source, which will enable new possibilities to evaluate material properties down to an atomic level. The linear accelerator (Linac), accelerates with help of electromagnetic fields, protons to a speed of 96.2 % of the light. Due to high power and the pulsing nature of the accelerator an extremely advanced electrical supply is required. This master´s thesis comprises a concept topology for solving the electrical supply. The electrical supply consists of two series connected steps, which will be stacked in modulators. The first step is a low voltage grid connected capacitor bank charger, the second step converts the power to a high voltage pulsing pattern. This project comprises the first stage (the capacitor charger) which consists of an Active Front End in series with a DC/DC-converter. The main objectives are to fulfil the international standards regarding power quality, where main focus will be on flicker, low frequency harmonics emission and unitary power factor. In order to fulfill these goals with pulsating loads connected, a completely new developed power control introduced. Mathematical models have been derived in order to verify the functionality and to tune all the developed controls. A complete final implementation is done with the help of Matlab Simulink to more in-depth verify the different control parameters. The full implementation is also managed to check that the international standards are met. Complete calculations of power losses are also presented with evaluation of results and possible improvements. Together with the limitations, goals of the degree project and basic equations are merely everything in this report derived. The topology is shown to be extremely effective with very good results in terms of output voltage quality and on flicker and low frequency harmonics impact on the grid. Almost every effects due to the pulsing output nature is totally erased seen from the grid side.

Supervisor: Dr. Carlos A. Martins

Examiner: Prof. Mats Alaküla

Opponents: Andreas Olenmark
Jens sloth

Abstract:
The thesis describes in detail the design process of an electric traction machine for a particular HEV application, an Electric Rear Wheel Drive (E-RWD) unit. The evolution of the design is presented, analyzing the effect of the different driving forces at the different stages. A new machine design methodology based on the description of the load profile in the form of driving cycles is introduced. The manufacturing of a prototype and the experimental validation of the design are also covered in this work. The proposed machine is tested both standalone, and integrated in the E-RWD unit onboard the vehicle. From the experience gained both from the design and the experimental testing phases, it appears that the performance of the machine is usually limited by its thermal capabilities. A way to enhance the cooling capabilities for conventional radial flux machines is presented, together with an additional machine design with a completely novel cooling concept based on direct cooling of laminated stator windings.

Supervisors:
Prof. Mats Alaküla (LTH)
Assoc. Prof. Avo Reinap (LTH)

External examiner:
Dr. Ing. Jörg Merwerth (from BMW, AG)

Examination committee:
Prof. Chandur Sadarangani (KTH)
Assoc. Prof. Anders Grauers (Chalmers)
Dr. Jonas Hellgren (AB Volvo)
Prof. Jinliang Yuan (LTH, reserve)

Description:
This work has been carried out at ConnectBlue AB. Various principles and methods to power a sensor in a wireless network have been studied. An implementation with a solar cell and a rechargeable battery (Li-ion) has been made.

Supervisors: Bengt Simonsson (IEA-LTH).
Examiner: Gunnar Lindstedt (IEA-LTH).

Abstract:
It is critical for the durability of power modules to maintain low enough temperature in its components (IGBTs and diodes).
The goal of this project was to examine methods to estimate the junction temperature of components in an IGBT module in real-time.
After studying literature on the subject, a model was developed using Foster-circuits and feed-back from the NTC-thermistor in the IGBT-module.
This model was tested in a simulation with temperature measured at a nearby point and phase-currents as inputs. Data for the cooling system (heatsink and fan) was estimated from lab experiments. Information about component characteristics was given in the datasheet for the IGBT-module.

Supervisors: Hans Bängtsson (IEA-LTH), Per Södergård (CG Drives & Automation).
Examiner: Mats Alaküla (IEA-LTH).
Opponents: Christoffer Gydenius, Anton Magnusson.