Bachelor/Semester/Master Theses

The electrification of construction machinery, such as excavators or dump trucks, has recently been gaining popularity due to numerous technical, economical, and ecological benefits. At HPE, concepts to replace hydraulic excavators with electrical counterparts are investigated. The excavator’s battery voltage can vary substantially around its nominal value (up to ±25%). To boost this voltage up to a constant DC-link voltage for a motor drive (with energy recuperation), a highly compact and efficient bidirectional boost converter is required. In this project, you will commission a prototype system of a given boost converter design. This task includes the PCB, the magnetic components (inductors), the cooling system and the implementation of converter control & safety functions in VHDL. Thereafter, you will test the system at multiple operating points. Finally, you will make improvements to the PCB and/or the inductive components for an improved prototype system based on your findings during testing.

Simon Beck, ETL F12, beck@hpe.ee.ethz.ch

25% Control 10% Hardware Design 10% Simulation 30% Testing 25% VHDL Coding

Interest and knowledge in power electronic systems, Interest and knowledge in hardware design, Working language: English/German

Dr. Jürgen Biela

Magnetic materials constitute inductors and transformers used in the manufacturing of power electronic converters, which enable the conversion of electrical energy. The magnetic material on which the project is focused is magnetic powder core, which is a mixture of magnetic particles homogeneously distributed into a non-magnetic material. As each particle is insulated from the others, the induced eddy currents are distributed within the particle itself. In this project, you will develop analytical models to describe the distribution of the induced eddy currents in particles with different shapes. The development of physics-based models that describe the losses in magnetic materials, such as the one proposed here, is part of a wider class of models that describe the power converters’ behaviour. These models are then implemented in Matlab, building a modelling architecture, and are essential for the virtual prototyping of power converters, which is a significant topic in power electronics. As a result, this project is linked to a relevant engineering problem.

Marco Cotti, ETL F11, cotti@hpe.ee.ethz.ch

50% Modelling 50% Theory

• Interest in power electronic systems and material science • Interest and knowledge in Electromagnetics, Working language: English

Dr. Jürgen Biela

At HPE, Wide Band Gap (WBG) semiconductor device models have been developed for SiC MOSFETs and GaN HEMTs. For an optimal converter design, accurate yet computationally efficient switching loss models of such semiconductor devices are needed. In this project, you will first derive and implement an analytical turn-off switching loss model for SiC MOSFETs in Matlab based on a publication. Then, you will simulate switching waveforms and calculate switching losses in LTspice. As a next step, you will validate and compare your implemented analytical model with both LTspice simulations and existing measurement results from an optimally designed PCB for a SiC Half-Bridge at different operating conditions. Finally, you will comprehensively evaluate the accuracy of the implemented model using both device characteristics from data sheets and those measured from a power device analyser at HPE.

Anliang Hu, ETL F11, hu@hpe.ee.ethz.ch

30% Theory 50% Implementation 10% Simulation 10% Testing

Interest in power electronics, knowledge in basic electric circuit theory

Dr. Jürgen Biela

The electrification of construction machinery, such as excavators or dump trucks, has recently been gaining popularity due to numerous technical, economical, and ecological benefits. Therefore, concepts to replace hydraulic excavators actuators with electric counterparts are investigated at HPE. To enable bidirectional power flow to such electric actuators, wireless power transmission (WPT) is employed. Thereby, the mechanical durability is increased compared to brush rings or external cables, while maintenance requirements are reduced. In this project, you will commission the prebuilt WPT converter hardware, which consists of the primary and secondary PCBs as well as the WPT transformer. After validating the basic functionality of the system (isolation, switching, V&I measurements, etc.), you will develop safety and control mechanisms in VHDL to enable the full operation of the converter. Finally, you will make adjustments to the PCBs and/or WPT transformer for an improved prototype system based on your findings during operation.

Simon Beck, ETL F12, beck@hpe.ee.ethz.ch

10% Control 10% Hardware Design 10% Simulation 35% Testing 35% VHDL Coding

Interest and knowledge in power electronic systems, Interest and knowledge in hardware design, Working language: English/German

Dr. Jürgen Biela

The electrification of construction machinery, such as excavators or dump trucks, has recently been gaining popularity due to numerous technical, economical, and ecological benefits. At HPE, concepts to replace hydraulic actuators with electrical counterparts are investigated. Wireless power and data transfer across a mechanical joint (e.g. of an excavator arm) enables nearly maintenance free operation of the joint. The data/communication channel needs to be immune to interference, capable of real-time communication, and reliable even in dirty environments, such as construction sites. Radio frequency (RF) communication has been identified as a promising option to establish such a communication channel. In this project, you will design a communication system with focus on the RF antenna and adapt it to a given joint geometry. You will use FEM tools to optimise the antenna and identify the most suitable RF frequency range considering available communication ICs. Finally, if time permits, you will build a prototype of the resulting RF communication system.

Simon Beck, ETL F12, beck@hpe.ee.ethz.ch

33% Hardware Design 33% Modelling 33% Simulation

Interest and knowledge in microwave/RF engineering, Interest in power electronic systems Working language: English/German

Dr. Jürgen Biela

GaN high-electron-mobility transistors (HEMTs) are increasingly popular in power electronic systems due to their advantages over Si/SiC devices. However, GaN HEMTs exhibit a dynamic behavior in on-state resistance, where the Rds,on immediately after switching on is higher than its DC value. Also, it has been found that the value of Rds,on is dependent on multiple factors, including the switching condition (hard or soft). The figure above shows an exemplary circuit to measure the Rds,on under hard or soft switching conditions. At HPE, a GaN HEMT is investigated for an inverter system, where accurate measurements of its dynamic Rds,on behavior are crucial for loss modeling and system optimization. In this project, you will design a setup for dynamic Rds,on measurements, covering circuit design, PCB layout, and FPGA code implementation. In case of a master thesis, you will validate the setup and measure the characteristics of the device.

Ruida Zhang and Anliang Hu (co-supervision), ETL G12, zhang@hpe.ee.ethz.ch

10% Coding 55% Hardware Design 15% Simulation 20% Theory

Interest/knowledge in design of power electronic systems, Working language: English

Dr. Jürgen Biela

EuroTube is focusing on the implementation of hyperloop vacuum transport infrastructure, with the first step being the DemoTube test track in Dübendorf, Switzerland and the next one being a 3km test track (AlphaTube) in canton Valais, Switzerland. AlphaTube is planned to be a 3 km long Hyperloop test track built using ½ scale concrete tubes of 2.2m. This will serve as a test and development facility, for "full-scale" technology research, with launch tests of vehicles at target speeds of 900 km/h. The top of the tube will be covered with solar panels. The aim of this master thesis is to propose a design of a DC/DC insulated converter integrated with the PV plant into the 3kV DC bus, taking into account the spatial peculiarities of a 3km long linear PV array. In a real system, voltages higher than 3kV will probably be used, so the proposed topology should be scalable to higher voltages if possible. The result of the thesis will later be integrated into an overall energy flow based model to define the AlphaTube Microgrid.

Antoine Juge, R&D Electrical Hardware Engineer, EuroTube

● Literature review ● Study of existing topology and technical limitations from MVDC Integration and galvanic insulated DC/DC usage ● PV and converter space distribution strategy analysis, definition of the optimum converter power level ● Design of a DC/DC converter model: Topology and switch technology definition, Coil sizing and design, Capacitor sizing and design, Energy flow and losses calculation, Filter design and harmonics level definition ● Optional : Control algorithm implementation

Electrical engineering student ● Knowledge of power electronics ● High motivation and interest in the topic ● Experience or interest in learning circuit simulation tools

Dr. Jürgen Biela

Moderne Brennstoffzellenfahrzeuge benötigen eine Druckluftversorgung, welche vorteilhaft mit Hilfe eines Turbokompressors realisiert wird. Der zugehörige Umrichter muss neben den funktionalen Spezifikationen eine geringe Baugrösse aufweisen und herausfordernden Kostenzielen gerecht werden. Um Marktanwendungen mit immer höher Ausgangsleistung der Brennstoffzelle zu unterstützen, muss auch die Umrichter-Ausgangsleistung kontinuierlich erhöht werden. Dazu sollen in dieser Arbeit verschiedene Möglichkeiten zur Erhöhung der Ausgangsleistung der vorhandenen Technologieplattform untersucht werden. Mögliche Ansätze liegen in der Parallelschaltung von mehreren Leistungshalbleitern, einer Optimierung der thermischen Anbindung der Halbleiter an die Wasserkühlung, sowie der Einsatz alternativer Modulationsverfahren, welche die Ausnutzung der Halbleiter- und Filterkomponenten verbessern. Zu Beginn dieser Masterarbeit soll daher basierend auf vorhandenen Rechenmodellen das Potential der verschiedenen Optimierungsansätze analytisch beurteilt werden. Basierend auf den theoretischen Resultaten sollen zielführende Massnahmen ausgewählt und anschliessend für die messtechnischen Überprüfung in einem Hardware-Prototyp implementiert werden. Im letzten Teil der Arbeit soll die erreichbare Leistungserhöhung durch Messungen am Prototyp verifiziert werden. Die Arbeit wird bei der ETH Spin-Off Firma CELEROTON TurboCell in Volketswil durchgeführt.

Christoph Gammeter, Celeroton AG, christoph.gammeter@celeroton.com

20 % Theory 40 % Implementation 40 % Testing

Vorlesungen «Leistungselektronik», «Design of Power Electronic Systems», und/oder «Power Electronics I/II»,  Hardware Testerfahrung, Working language: English/German

Dr. Jürgen Biela

Magnetic components, such as transformers and inductors, are pivotal for advancing the field of power electronics. Leveraging these components to their full capability is essential for enabling the optimal use of Wide Bandgap semiconductors in power electronics applications. Frenetic, a pioneering startup based in Madrid & San Francisco with research office in Zurich, offers comprehensive solutions for magnetics from design to production, emphasizing the importance of accurate modelling. Currently, we are seeking motivated students that work on extracting the parasitic capacitances of transformers and their inclusion in equivalent circuits. In this work you will develop and implement models based on Maxwell’s equations and artificial intelligence. Ultimately, you will design and build transformers for model verification by measurements and perform FEM simulations. You will gain hands-on experience, merging theory with practice, contributing to significant advancements in power electronics.

Dr. Richard Schlesinger, richard.schlesinger@frenetic.ai

40 % Coding 20 % Laboratory 40 % Theory

Interest and knowledge in power electronic systems, Interest in the physics, modelling, and design of magnetic components, Working language: English/German

Dr. Jürgen Biela

Hyperloop is the next evolution of rail-based transportation, combining the speed of aircraft and the efficiency of the railway industry. EuroTube is focusing on the implementation of hyperloop infrastructure, with the first step being the DemoTube test track in Dübendorf, Switzerland. In DemoTube, test vehicles will be propelled by a track mounted, long primary linear induction motor (LIM). A track mounted motor solves the problem of transferring electrical power to a vehicle within a vacuum tube and drastically reduces the weight of the vehicle. However, the long primary needs to be split into segments to ensure the efficient operation of the motor. In this master thesis, the student will investigate the strategy for the switching of the motor segments, the transient effects caused by it, possible mitigation measures (i.e. filters) and propose a hardware setup for the final configuration in the test track.

Please email your CV and transcript to ioannis.stavropoulos@eurotube.org

● Literature review on induction motors, transient phenomena and filters ● Simulation of the electrical circuit and determination of the best possible switching strategy and hardware ● Optional: Proposal of electrical hardware ● Summary of the results and compilation of a written report

● Electrical engineering student ● Knowledge of power electronics and electrical motors ● High motivation and interest in the topic ● Able to work independently and be creative ● Experience or interest in learning circuit simulation tools

Dr. Jürgen Biela

Hyperloop is the next evolution of rail-based transportation, combining the speed of aircraft and the efficiency of the railway industry. EuroTube is focusing on the implementation of hyperloop infrastructure, with the first step being the DemoTube test track in Dübendorf, Switzerland and the next one being a 3km test track (AlphaTube) in canton Valais, Switzerland. In AlphaTube, test vehicles will be propelled by a track mounted, long primary linear electric motor. In this master thesis, the student will investigate different linear motor types and topologies for the future 3km AlphaTube vacuum transport demonstrator. The track-side (long primary) motor will be 400m long and will propel the vehicle to 900km/h, reaching a peak power of 10MW. Possible motor types of interest are the permanent magnet synchronous motor and the synchronous reluctance motor, while both double-sided and single-sided topologies can be investigated. The designs will be compared to the existing linear induction motor design of EuroTube for efficiency, cost and optimal usage of materials. The motor designs should be verified in a 2D or 3D finite element analysis software.

Please email your CV and transcript to ioannis.stavropoulos@eurotube.org

● Literature review on linear electric motors ● Derivation of the equivalent electrical circuit and hardware ● Finite element analysis of different motor types and topologies ● Summary of the results and compilation of a written report

● Electrical engineering student ● Knowledge of electrical motors ● High motivation and interest in the topic ● Able to work independently and be creative ● Experience or interest in learning circuit simulation and finite element analysis tools

Dr. Jürgen Biela

Magnetic components, such as transformers and inductors, are pivotal for advancing the field of power electronics. Leveraging these components to their full capability is essential for enabling the optimal use of Wide Bandgap semiconductors in power electronics applications. Frenetic, a pioneering startup based in Madrid & San Francisco with research office in Zurich, offers comprehensive solutions for magnetics from design to production, emphasizing the importance of accurate modelling. Using parallel windings is a common practice to increase the conducting cross section for high currents. However, current can balance inhomogeneously across these parallels depending on the energy minimum of the system. This results in lower efficiency and in the worst case the component burns down. Your task is to investigate and evaluate efficient winding arrangements that overcome this problem, and thus, solve a common problem of the industry. You will analyze this effect using various tools such as FEM and other modelling techniques and verify the results with hardware measurements. This way, you will gain hands-on experience, merging theory with practice, contributing to significant advancements in power electronics. Promising results might be published at a renowned conference.

Dr. Richard Schlesinger, richard.schlesinger@frenetic.ai

40 % Modelling & Theory 20 % Coding 25 % Design 15 % Measurements

Interest and knowledge in power electronic systems, Interest in the physics, modelling, and design of magnetic components, Working language: English/German

Dr. Jürgen Biela

Magnetic components, such as transformers and inductors, are pivotal for advancing the field of power electronics. Leveraging these components to their full capability is essential for enabling the optimal use of Wide Bandgap semiconductors in power electronics applications. Frenetic, a pioneering startup based in Madrid & San Francisco with research office in Zurich, offers comprehensive solutions for magnetics from design to production, emphasizing the importance of accurate modelling. Currently, we are seeking motivated students that work on LLM-/Machine Learning-based approaches for the design of transformers and inductors in power electronics. Your goal is to obtain an optimized design regarding efficiency and power density. Ultimately, the design has to be verified with a real-life implementation. You will gain hands-on experience, merging theory with practice, contributing to significant advancements in power electronics.

Dr. Jonas Mühlethaler, jonas@frenetic.ai

40 % Coding 20 % Laboratory 40 % Theory

Interest and knowledge in power electronic systems, Interest in the physics, modelling, and design of magnetic components, Working language: English/German

Dr. Jürgen Biela

The hyperloop transport system is expected to be capable of running at speeds up to 900 km/h. Consequently, the architecture of the power system for propulsion and levitation is key to ensure efficiency and high performance during the operation of the system. While hyperloop is still in development, many system topologies can be proposed: power on-board or off-board, hybrid energy storage systems, EDS/EMS levitation systems and so on.

Please email your CV and transcript to lorenzo.benedetti@eurotube.org

This thesis will have the following objectives: 1. Starting from the expected trajectory of the vehicle, the power profile relative to the propulsion and levitation systems will be extracted and compared with the corresponding one of high speed railway. 2. After having established the expected performance, the thesis will focus on which power system architecture is most suitable. In particular: a. Few potential topologies will be identified b. Preliminary design of the main components c. Simulation of the power flow d. Evaluation of performance 3. Comparison of the proposed topologies and identification of potential improvements The final project focus and work packages will be decided during the first meetings.

● Electrical engineering student ● Knowledge and willingness to learn about, power electronics, electrical motors and magnetic levitation ● High motivation and interest in the topic ● Able to work independently and be creative ● Experience or interest in learning circuit simulation tools

Dr. Jürgen Biela

At HPE, model predictive control (MPC) is investigated as an alternative control method for power electronic systems since converters with MPC can achieve a fast dynamic behavior and incorporate system constraints. The challenging part is that for implementing MPC an optimisation problem has to be solved with limited resources in embedded systems within every sampling interval in real-time, which is typically very short in power electronic systems (range of a few μs). In this project, you will develop a toolbox for enabling a rapid realtime implementation of MPC based on implemented quadratic program (QP) solvers using the Intel high-level-synthesis (HLS) compiler. The toolbox will execute an optimization routine to compare the performance considering hardware resource constraints and verify the implementation through FPGA-in-the-loop experiments.

Min Jeong, ETL F14, jeong@hpe.ee.ethz.ch

30% Coding 50% Implementation 20% Simulation

Interest/basic knowledge in coding and FPGA, Working language: English

Dr. Jürgen Biela

The high blocking voltages of the latest wide-bandgap semiconductors have enabled power electronic converter systems to operate within the medium voltage range. A core component of these systems is the medium-frequency transformer (MFT), which provides the necessary galvanic isolation. To insulate the medium voltage side from the low voltage side, a significant fraction of the MFT’s overall volume is consumed by the insulation. Therefore, designing an optimal MFT also necessitates optimising its insulation system. This is where your work will be crucial. In this project, you will implement an optimisation routine in MATLAB that integrates state-ofthe- art insulation models, which are currently developed at HPE. Your optimisation results will uncover previously unutilised potential in MFT design by addressing limitations caused by the absence of insulation modelling. As a master’s thesis student, you will also have the opportunity to build and experimentally test the optimised transformer, bringing your design from theory to practical validation.

Bastian Korthauer, ETL G12, korthauer@hpe.ee.ethz.ch

50% Coding 15% Hardware Design 5% Implementation 15% Testing 15% Theory

Interest in power electronics, Interest in high voltage engineering,Interest in code optimisation Working language: English/German

Dr. Jürgen Biela

Using litz wire is one of the most efficient ways to reduce high frequency winding losses. However, only perfectly twisted litz wire, in which each strand conducts the same current and no eddy currents are circulating between different strands, can effectively reduce the high frequency winding losses. To achieve this goal, the proper twisting process is critical. Therefore, mathematical models calculating the strand current affected by the twisting parameters, are developed at HPE. To validate these models, the current conducted by different strands needs to be measured. In this project, you will begin with a literature review to investigate different current measurement methods and select the suitable one. Moreover, based on the selected current measurement method, a measurement system, which can automatically measure the currents for at least 20 strands, needs to be designed. FEM and circuit simulation are needed to validate your design. Finally, the validated design will be implemented and experimentally tested.

Qingchao Meng, ETL F17, meng@hpe.ee.ethz.ch

30% Hardware Design 30% Implementation 30% Simulation 10% Testing

Interests in hardware design and measurements, Working language: English/German

Dr. Jürgen Biela

Due to a high efficiency and a high power density, isolated DC-DC converters are widely used in power supplies of modern data centers, battery chargers of electric vehicles, etc. A key component of such isolated DC-DC converters is the medium frequency transformer (MFT), in which often litz wire is used to reduce the losses. Litz wire is made of numerous twisted strands to prevent the bundle-level eddy current. However, the termination of the litz wires has a significant impact on the current distribution between strands, and could result in high eddy current losses. Therefore, the impact of the wire termination on the current density distribution and the eddy current losses in litz wire must be investigated. In this project, 3D FEM is used to investigate the effects. Your task is to model the 3D geometry of litz wire by a mathematical algorithm. Furthermore, the current density distribution and the eddy current losses should be calculated for different termination strategies and for different litz wire geometries by FEM. The impact of improper terminations should be qualitatively/quantitatively analysed.

Qingchao Meng, ETL F17, meng@hpe.ee.ethz.ch

20% Coding 60% Simulation 20% Theory

Interests in FEM simulation and modeling, Interests in power electronics, Working language: English/German

Dr. Jürgen Biela

At HPE, core loss models are developed for optimising different inductor or transformer designs. Recently, HPE released a novel innovative core loss model based on physical derivations. So far, the current implementation of the model is done only in frequency domain. To integrate the new core loss model in circuit-based simulation tools (such as PLECS or SPICE), the model must be modified to operate also in time domain. In this project, you will first analyse the frequency domain implementation. In a second step you will develop and implement a method to adapt the outcome of the core loss model so that it can be used in timedomain simulations using PLECS, based for instance on equivalent circuits representing the core losses. Thanks to this project, you will learn how to combine coding and physical modelling to develop advanced electronics design automation (EDA) tools for power electronics.

Dr. Théophane Dimier, ETL F17, tdimier@hpe.ee.ethz.ch

25% Coding 25% Implementation 25% Modelling 25% Simulation

Interest/knowledge in circuit, simulation tools (PLECS, SPICE...), Knowledge in Matlab Working language: English

Dr. Jürgen Biela

In converter systems, for example a Buck converter, inductors often play an important role. Specifically, its inductance value is crucial for a proper converter operation. Exposing (foil) inductors to short current rise times could result in a reduction of the inductance value by up to 25 %. This is due to the shielding effect in foil windings. This reduction of the inductance affects the converter operation, more specifically, the current ripple. In this project, you will use analytical models to calculate the frequencydependent inductance of inductors over a wide frequency range. Based on these models, you will investigate and apply suitable methods in order to perform time-domain circuit simulations of the converter system with a varying, time-dependent inductance. Furthermore, you will work on developing sophisticated models that predict the behavior of the converter system the inductor is employed in.

T. Ewald, ETL F18, ewald@hpe.ee.ethz.ch

20% Implementation 35% Modelling 10% Testing 35% Theory

Interest in analytical modelling, Understanding of converters, Experience in Matlab/Comsol, Working language: English/German

Dr. Jürgen Biela

At HPE, various basic switching cell configurations are investigated to optimise the design of power electronics converter systems. A switching cell design consists of the semiconductor devices, the gate drivers, the DC-link capacitors, and the heat sink. The arrangement of those components has significant impact on the electrical and thermal performance of the converter. In this project, you will design PCBs for a few different half-bridge switching cell configurations. The PCB design will be performed in Altium and evaluated in terms of parasitics. Eventually, you will build and test the designed switching cell as well as measure the switching losses. In case of a master thesis, a comparison of the different arrangements will follow in order to examine the trade-off between efficiency and power density.

G. Papadopoulos, ETL F13, papadopoulos@hpe.ee.ethz.ch

40% Hardware Design 20% Simulation 30% Testing 10% Theory

Interest and knowledge in power electronic systems, Interest/knowledge in PCB design, and testing, Working language: English

Dr. Jürgen Biela

The design of power electronic systems is typically performed with optimisation procedures, where analytical models of the system and its components are used. One important component of power electronic converter systems is the switching cell (i.e. a bridge leg + DC-link capacitor). At HPE, various switching cell configurations are investigated to optimise the design of power electronics converter systems. A switching cell design consists of the semiconductor devices, the gate drivers, the DC-link capacitors, and the heat sink. The arrangement of those components has significant impact on the electro-thermal performance of the converter. In this project, you will design PCBs for switching cells based on the X3D format using an existing software tool developed in Matlab. These PCBs will be evaluated and optimised in terms of parasitics. Finally, you will compare the simulation results of the PCBs designed in the X3D format with a PCB, which you will design in Altium. In case of a master thesis, an experimental validation of the results will follow.

G. Papadopoulos, ETL F13, papadopoulos@hpe.ee.ethz.ch

20% Coding 30% Hardware Design 30% Simulation 20% Theory

Interest/knowledge in PCB design and testing, Interest in power electronic systems and coding, Working language: English

Dr. Jürgen Biela

The design of power electronic systems is typically performed with optimisation procedures, where analytical models of the system and its components are used. One important component of power electronic converter systems is the switching cell (i.e. a bridge leg + DC-link capacitor). At HPE, various switching cell configurations are investigated to optimise and simplify the design of power electronics converter systems. One of the major components of a switching cell is the heat-sink. The performance of the heat sink/cooling system has a significant impact on the efficiency and power density of the converter. In this project, you will develop an analytical thermal model of the switching cell and implement the 3D representation in the X3D format based on a software tool developed in Matlab. Finally, you will intergrate the switching cell model into a converter system and evaluate the temperature distribution using FEM simualation. The final goal is to automate the process of performing thermal simulations of different converter arrangements.

G. Papadopoulos, ETL F13, papadopoulos@hpe.ee.ethz.ch

30% Coding 40% Modelling 20% Simulation 10% Theory

Interest and knowledge in power electronic systems, Interest/knowledge in thermal modeling, Working language: English

Dr. Jürgen Biela

The design of power electronic systems is typically performed with optimisation procedures, where analytical models of the system and its components are used. One important component of power electronic converter systems is the switching cell (i.e. a bridge leg + DC-link capacitor). At HPE, various switching cell configurations are investigated to optimise the design of power electronics converter systems. A switching cell design consists of the semiconductor devices, the gate drivers, the DC-link capacitors, and the heat sink. The arrangement of those components has significant impact on the electro-thermal performance of the converter. In this project, you will parametrise the mechanical layout of different switching cell arrangements and design the 3D representation in the X3D format based on a software tool developed in Matlab. The goal is to have mechanical models of the switching cell that can be used to automate the design procedure of a converter and speed up the process of performing thermal and parasitic simulations of different switching cell arrangements.

G. Papadopoulos, ETL F13, papadopoulos@hpe.ee.ethz.ch

20% Coding 30% Modelling 30% Simulation 20% Theory

Interest and knowledge in PCB design, Interest in coding, Working language: English

Dr. Jürgen Biela

At HPE, research is performed on Plasma Pulse Geo Drilling (PPGD) as a potential alternative to traditional mechanical drilling for harnessing geothermal energy in large depths (up to 10 km). PPGD technology is based on applying high voltage (several hundreds of kV) electrical discharges to rocks. These discharges create a plasma channel inside the rock that effectively fragments the rock. A high voltage pulse generator must be positioned near the drilling electrodes for applying those discharges to the rock. Therefore, the generator must be compact to fit inside the drilling hole. A Marx generator is a possible interesting option for ruling the pulse generator. In this project, you will use FEM simulations to model the components of Marx generator in order to avoid unwanted high electrical fields which may cause electrical failures. Furthermore you will design customised inductors for the equipment. Finally, you will present a possible optimised design for the application.

Joao Martins Junior, ETL G12, martins@hpe.ee.ethz.ch

30% Hardware Design 30% Modelling 10% Simulation 30% Theory

Knowledge in FEM simulations; Knowledge in Matlab; Knowledge in high voltage engineering, Working language: English

Dr. Jürgen Biela

At HPE, research is performed on Plasma Pulse Geo Drilling (PPGD) as a potential alternative to traditional mechanical drilling for harnessing geothermal energy in large depths (up to 10 km). PPGD technology is based on applying high voltage (several hundreds of kV) electrical discharges to rocks. These discharges create a plasma channel inside the rock that effectively fragments the rock. A high voltage pulse generator must be positioned near the drilling electrodes for applying those discharges to the rock. Therefore, the generator must be compact to fit inside the drilling hole. A Tesla transformer is a possible interesting option for generating the required high voltage pulses. In this project, you will use analytical as well as FEM models to optimise a Tesla transformer to meet the size and efficacy constraints of the project. At the end, you will present a possible design solution. In case of a master thesis, a virtual prototype can be designed.

Joao Martins Junior, ETL G12, martins@hpe.ee.ethz.ch

20% Hardware Design 40% Modelling 10% Simulation 30% Theory

Knowledge in Matlab; • Knowledge in high voltage engineering. Working language: English

Dr. Jürgen Biela

Magnetic materials are key components in electrical machines and power electronics converters and are present in many applications where electrical energy is processed. In order to design the components in an optimised way, it is necessary to know all losses during the design phase, including the losses occurring in the magnetic core. In this project you will investigate the relevant electromagnetic phenomena of interest in magnetic components used in power electronics, in particular in magnetic cores made of laminated materials such as electrical steel, amorphous or nanocrystalline. FEM simulation will be used to analyse the electromagnetic behaviour of the laminated cores. The phenomena to be analysed include the magnetic field distributions and eddy currents within the magnetic laminations, the effect of magnetic fields perpendicular to the plane of the lamination and the electrical interactions between the laminations, the study of these phenomena will be applied to the assessment of power losses.

Miguel Astudillo, ETL F11, astudillo@hpe.ee.ethz.ch

20% Coding 20% Modelling 40% Simulation 20% Theory

Interest in power electronic systems and material science, Interest and knowledge in physics simulation of electromagnetics, Working language: English

Dr. Jürgen Biela