Semester-/Bachelor Projects and Master Theses

Bachelor Project / Semester Project

Most of current mechanical circulatory support systems use a percutaneous driveline and place the motor inverter outside of the human body. The use of a TET eliminates the driveline and the associated risks for infections but makes it necessary to place the motor inverter inside the body. An ultra compact inverter was developed based on an STM32 microcontroller. The PCB must now be assembled and commissioned. For this task, corresponding embedded software must be developed. A PLECS model of the expected motor load shall be derived, simplifying the software development using the integrated code generation feature. The prototype inverter shall then be characterized using an inductive load and an available motor prototype. As an additional task, the integration of a sensor interface using a CPLD shall be evaluated and realized. Based on the gained knowledge, a second optimized version of the converter shall be specified and designed.

- 20% literature - 50% embedded and PC software development - 20% measurements - 10% report & documentation

- Lectures in power electronic systems

Andreas Horat, ETL H 14, horat@ams.ee.ethz.ch

Prof. Dr. Ch. Franck

Bachelor Project / Semester Project / Master Thesis

Wide-bandgap (WBG) semiconductors are becoming more popular, especially in electric transportation and industrial automation, where high efficiency and power density are crucial. It is important to identify those converter variants that take most advantage of the superior performance of WBG devices. In this thesis, you compare various threelevel three-phase inverters for next-generation variable speed drives. The choice of the bridge-leg topology significantly impacts the overall system performance, efficiency, and reliability of these systems. Thus, you will model and simulate the most interesting three-level bridge-leg topologies using PLECS. Further, you will define performance metrics for a multi-objective comparative evaluation (efficiency, mission-profile efficiency, power density, etc.) and implement a MATLAB routine to calculate these performance indicators for each topology. Finally, this allows a comprehensive comparison of the performance limits (Pareto fronts).

- 15% literature review - 20% modeling and simulation - 40% multiobjective optimization and comparison - 15% report & documentation

- Lectures in power electronic systems

Rahel Herzog, ETL H 17, herzog@ams.ee.ethz.ch

Prof. Dr. Ch. Franck

Bachelorarbeit / Semesterarbeit / Masterarbeit

In industriellen Applikationen werden häufig Mehrachsensysteme eingesetzt. Durch die mechanischen Verbindungen und deren begrenzter Steifigkeit können die Aktions- und Reaktionskräfte der Motoren zu unerwünschten Kopplungen zwischen den Achsen und zu mechanischen Schwingungen im System führen. Zur Systemanalyse bietet es sich an, gleich die im System verbauten Servomotoren mit integrierter Positionserfassung zu verwenden. Dazu müssen diese geeignet angeregt und die resultierenden Bewegungen gemessen und analysiert werden. Das Ziel der Arbeit ist die Entwicklung eines Tools, das in einem Mehrachsensystem auf Basis der eingebauten Servomotoren bei verschiedenen Positionen und Frequenzen automatisierte Messungen durchführt, mechanische Kopplungen und Schwingneigungen erkennt und die Resultate visualisiert. Die Arbeit wird in Zusammenarbeit mit der Firma NTI AG (www.LinMot.com) in Spreitenbach durchgeführt.

- 50% Softwareentwicklung (LabView) - 40% Systemanalyse und Messtechnik - 10% Dokumentation

Interesse an Servoantriebstechnik und Systemanalyse

Dr. Daniel Ausderau, LinMot, daniel.ausderau@linmot.com

Prof. Ch. Franck

Semester Project / Master Thesis Project

Levitronix specializes in critical bioprocessing technologies, producing components like levitated centrifugal pumps, flow sensors, and pinch valves for applications such as tangential flow filtration, cell culture perfusion, and vaccine production. These components are crucial for highperformance biotechnological laboratory systems. This project aims to develop a modular system that securely and precisely positions various components, such as sensors, actuators, and filters, tailored to each specific application. The system shall enhance ease of use, installation, and operation in laboratory environments. Using rapid prototyping through Solid- Works and 3D printing, the design will undergo iterative improvements to be production- ready and compatible with injection molding processes. Key design goals include production feasibility for manufacturing, laboratory compatibility with compact and easy-to-clean structures, and optimized fluid dynamics that reduce fluid volume and eliminate dead zones or high-shear areas.

- 30% CAD modeling & simulation - 30% prototyping (3D-printing) - 30% testing and validation - 10% report & documentation

- Basic knowledge of CAD software (e.g., SolidWorks) - Interest in mechanical design for life sciences - Prior experience with 3D printing is a plus

Fabian Frank, Levitronix GmbH, BioprocessInnovationTeam@levitronix.com

Prof. Ch. Franck

Bachelor Project / Semester Project / Master Thesis

Bioreactors for cell cultivation and vaccine production are typically equipped with mechanically supported stirring bars. These stirring rods require a lot of space and handling during cultivation is very time-consuming. A novel method is the use of magnetically mounted bottom stirrers, which are to be investigated in this work. The use of such drives would offer enormous advantages in terms of flexibility and space management. However, it must first be shown that the mixing efficiency is at least equal with the state-of-the-art technology. This is to be achieved in this work by means of CFD simulations and mixing time measurements. The final aim of the work is to analyze to what extent the design of the mixer (diameter, height, geometry, placement) and reactor tanks (diameter, height, shape) have an influence on performance and to derive design specifications accordingly.

- 60% simulation - 30% measurements - 10% report & documentation

Interest in simulation, fluid dynamics, mechatronics and practical lab work

Dr. Daniel Steinert, Levitronix GmbH, steinert@levitronix.com

Prof. Ch. Franck

Bachelor Project / Semester Project / Master Thesis

Levitronix specializes in critical bioprocessing technologies, producing components like levitated centrifugal pumps, flow sensors, and pinch valves for applications such as tangential flow filtration, cell culture perfusion, and vaccine production. These components are crucial for highperformance biotechnological laboratory systems. This project aims to develop a bistable solenoid pinch valve, enabling further miniaturization based on an existing valve. This will require a completely new bistable actuator design and a specialized concept. The actuator is to be designed and optimized using magnetostatic FEM simulations. Subsequently, the actuator and the closure mechanism are to be designed in SolidWorks and manufactured using a combination of 3D-printed or machined parts. In the final step, the valve will be assembled, the simulation results verified, and its functionality tested in a fluid circuit.

- 30% simulation - 30% CAD-modeling - 30% testing and validation - 10% report & documentation

- Basic knowledge of CAD software (e.g., SolidWorks) - Interest in mechanical design for life sciences - Interest in simulation

Peter Mayr, Levitronix GmbH, mayr@levitronix.com

Prof. Ch. Franck

Master Thesis

Bucher Hydraulics provides solutions such as electrohydraulic systems (EHS) and xPTOs with a matching motor drive inverter (Bucher Mobile Drive, BMD), targeting the electrification of heavy mobile machinery and off-highway vehicles. In this project, first you will first carry out a literature review to understand the electromagnetic energy conversion principle and field-oriented control (FOC) of electrically excited synchronous machine (EESMs). The electrical parameters of the synchronous machine are estimated either analytically or using FEM simulations of an EESM. The control concept and the drive topology will be explained in detail. The dq-modelling and FOC of the EESM will be implemented in Matlab/Simulink. The expected model outputs are voltage, current, power, losses, power factor for the entire torque-speed plane. The thesis result provides incite knowledge about drive concept and operating characteristics of the electrohydraulic system. Finally, a proposal will be made to implement the model into the BMD software. The master thesis is carried out in the Advanced Technology team of Bucher Hydraulics AG in CH-6345 Neuheim.

- 40% modeling and drive concept (Matlab/Simulink) - 40% software calculation (analytical/FEM) - 10% hardware - 10% documentation

Lectures in power electronic systems and/or electric machines

Dr.-Ing. Ahamed Bilal Asaf-Ali, Bucher Hydraulics AG, ahamedbilal.asafali@bucherhydraulics.com

Prof. Ch. Franck

Semester Project / Master Thesis

In this project first the means of constructing a variable inductor are to be investigated based on the two principles shown above. In the first the magnetic coupling between two series connected spherical windings can be adjusted to vary the inductance while in the second the magnetic core is moved linearly in and out of the coil to vary the inductance. Given the targeted specifications of the variable inductor, FEM simulations should be used to evaluate the best solution and facilitate the design of the variable inductor. To enable integration into an automated switch-loss measurement setup, mechanical adjustment should be precisely controlled, ideally in a closed-loop system with real-time position feedback, using a servo or stepper motor interfaced with a microcontroller, allowing fine-tune selection of the inductance from a MATLAB script.

- 20% research & FEM simulations - 60% hardware realization - 5% measurements - 15% report & documentation

- Lectures in power electronic systems - Interest in hardware design - Initial hardware experience is a plus

Sven Weihe, ETL H 18.1, weihe@ams.ee.ethz.ch

Prof. Dr. Ch. Franck

Semester Project / Master Thesis

novel agitation method of bioreactors for cell cultivation and vaccine production is the use of magnetically levitating stirrers. The use of such drives offers enormous advantages in terms of flexibility and space management. This new approach requires a highly customized gassing device to aerate the liquid as efficiently as possible. Previous characterizations using small-scale bioreactors have demonstrated the suitability of this technology. The aim of this project is to develop a prototype setup, including a new mixer impeller and a gassing system, for highvolume bioreactors to extend existing data. This includes designing (CAD modelling) and realization using additive and traditional manufacturing processes. The project emphasizes hands-on laboratory work, where the newly constructed rig is used to investigate and analyze the scalability of critical system properties, including mixing times and gas transfer rates. Ultimately, the goal is to prove the scalability of the newly developed bioreactor agitation system through iterative design and process optimization.

- 45% product development (designing, prototyping, realization) - 45% lab work and measurements - 10% report & documentation

Interest in product development, mechatronics and practical lab work in an industrial environment

Nils Schlegel, Levitronix GmbH, nils.schlegel@levitronix.com

Prof. Dr. Ch. Franck

Bachelorarbeit / Semesterarbeit / Masterarbeit

Hochdynamische tubulare Linearmotoren werden auch in Kombination mit magnetischen Federn eingesetzt. Dabei werden magnetische Federn direkt in den Linearmotor integriert, was auch kombinierte magnetische Erregereinheiten erfordert, welche aus verschiedenartigen Permanentmagneten aufgebaut sind. In dieser Arbeit soll ein automatisiertes Testgerät entwickelt werden, mit dem zylinderförmige magnetische Erregereinheiten nach der Fertigung schnell und zuverlässig bezüglich deren magnetischen Qualität geprüft werden können. Das Testgerät soll das Magnetfeld um den Umfang der Erregereinheit über die ganze Oberfläche mithilfe eines Sensorarrays und der Verwendung von Antrieben erfassen können. Das nach dem Oberflächen-Scan erfasste Magnetfeld soll geeignet ausgewertet werden, um die magnetische Qualität des Prüflings anforderungsgemäss beurteilen zu können. Die Arbeit wird in Zusammenarbeit mit der Firma NTI AG (www.LinMot.com) in Spreitenbach durchgeführt.

- 50% Antriebstechnik, Sensorik und Messtechnik - 40% Softwareentwicklung (LabView) - 10% Dokumentation

Interesse an Testsystemen (Antriebstechnik, Sensorik, Datenanalyse)

Dr. Daniel Ausderau, LinMot, daniel.ausderau@linmot.com

Prof. Dr. Ch. Franck

Bachelorarbeit / Semesterarbeit

Bei Anwendungen mit Linearmotoren ist neben der Positionserfassung häufig auch die Kenntnis der an die Last übertragenen Kraft wichtig. Dafür kommen zusätzlich Kraftsensoren zum Einsatz, welche aus praktischen Gründen oft motorseitig verbaut oder sogar in den Motor integriert werden. Davon und von der Anwendung abhängig zeigen sich im dynamischen Betrieb unterschiedliche systematische Messfehler, welche in dieser Arbeit identifiziert und quantifiziert werden sollen. Relevante Messfehler sollen mithilfe der Kenntnis des Systemzustandes durch geeignete Massnahmen (Kompensation, Filterung, ...) minimiert werden. Dabei ist auch der Einsatz eines Beschleunigungssensors vorzusehen. Die Arbeit wird in Zusammenarbeit mit der Firma NTI AG (www.LinMot.com) in Spreitenbach durchgeführt.

- 50% Antriebs- und Messtechnik - 40% Softwareentwicklung - 10% Dokumentation

Interesse an Antriebstechnik und Signalverarbeitung

Dr. Daniel Ausderau, LinMot, daniel.ausderau@linmot.com

Prof. Dr. Ch. Franck

Master Thesis

The CO2 emission target is recently driving a trend towards electrification of heavy mobile machinery, buses, and trucks (offhighway vehicles), where electrohydraulic systems (EHS) and xPTOs are used for auxiliary functions. The electric motor driving the hydraulic pump operates in a wide range of different load conditions. Whereas the output current of the drive is limited to keep the ohmic stator losses and hence the stator temperature within limits, in the stator within the limit, there is not direct measurement of the rotor temperature. Therefore, it is necessary to estimate the rotor temperature to maximizing the motor performance (temporary overload) while protecting the permanent magnets in the rotor from demagnetization due to overtemperatures. In this project, you will employ data-driven machine-learning models to provide an estimate of the dynamic temperature distribution in various parts of an electric motor subject to dynamic load changes. The master thesis is carried out in the Advanced Technology team of Bucher Hydraulics AG in CH-6345 Neuheim.

- 25% thermal modeling (e.g. Matlab/Simulink) - 65% machine learning (Python) - 10% documentation

Lectures in electric machines and machine learning

Dr.-Ing. Ahamed Bilal Asaf-Ali, Bucher Hydraulics AG, ahamedbilal.asafali@bucherhydraulics.com

Prof. Dr. Ch. Franck

Semester Project / Master Thesis

Integrating the numerous data signals from inputs and outputs of bioreactor components used for cell cultivation and vaccine production into an interactive and complex embedded system is essential. A new approach for bioreactors involves several individual Levitronix components, such as magnetically levitating agitators and pumps. Those components will be accompanied with the required sensors and control units for bioprocessing. This project aims for the software integration of Levitronix components and external sensors into an embedded system, leading to a more robust and efficient bioprocess control system. This includes choosing the required sensors and control units, designing necessary embedded system related hardware, and programming the integration into the embedded system. The newly developed system focuses on intuitive control with a highly flexible and modifiable user interface. Ultimately, the developed setup shall be tested and evaluated.

- 25% hardware design - 40% programming - 25% testing - 10% report & documentation

Interest in embedded systems, programming, mechatronics and practical lab work in an industrial environment

Nils Schlegel, Levitronix GmbH, nils.schlegel@levitronix.com

Prof. Dr. Ch. Franck

Semester Project / Master Thesis

There are currently no commercially available transcutaneous energy transfer (TET) systems. Based on the work previously done at the Power Electronic Systems Laboratory of ETH Zürich, the goal is to develop an improved TET system utilizing the latest (semiconductor) technologies to reduce power losses and mechanical dimensions. The project starts with thoroughly understanding the previously developed TET system and the current state of research. Based on that, an improved system will be designed employing the latest research advancements. A hardware prototype will be developed and built. This includes the mechanical as well as the electrical design. For the commissioning, some basic software will be developed. Finally, you will verify the performance of the realized system, including measurements of power losses and tissue heating.

- 30% FEM & circuit simulation - 40% hardware realization - 20% measurements - 10% report & documentation

- Lectures in power electronic systems - Interest in hardware design - Initial hardware experience is a plus

Andreas Horat, ETL H 14, horat@ams.ee.ethz.ch

Prof. Ch. Franck

Semester Project / Master Thesis

Electromagnetic compatibility (EMC) is essential in any power electronic converter. To comply with international standards, electromagnetic interference (EMI) mitigation is crucial. EMI filters attenuate unwanted high-frequency noise emission at the input and/or output ports to acceptable levels and thus prevent disruption of other nearby devices. EMI filters can be built with passive components only or can also feature active components. In this project, you will first familiarize yourself with EMI filter theory (modeling, measurement methods, standards), and then you will implement a promising hybrid filter concept, featuring both active and passive components. Finally, you will test your filter with an existing inverter and compare your results with previous measurement results featuring various filter topologies.

- 20% literature review & circuit simulation - 30% hardware design & commissioning - 40% measurements - 10% report & documentation

- Lecture in design of power electronic systems - Interest in hardware design and characterization - Initial hardware experience is a plus

Rahel Herzog, ETL H 17, herzog@ams.ee.ethz.ch

Prof. Ch. Franck

Semester Project / Master Thesis

The Shuttle pump is a novel linear-rotary blood pump. This total artificial heart works with a piston, which pumps in linear direction and opens and closes the valves by rotating the piston. The tubular linear actuator is paired with a modified rotary actuator using only a fraction of the usual permanent magnets. An eddy current based position sensor is used to measure the linear and rotational position. A functional prototype of the drive system was designed and built during a previous PhD thesis. Based on this prototype, multiple final pump demonstrators were manufactured. The goal of this project is to fully commission these demonstrators at ETH Zürich and afterwards assess the hydrodynamic performance in collaboration with the Medical University of Vienna.

- 10% documentation study - 80% hardware commissioning and measurements - 10% report & documentation

- Experience in power electronics and electric machines - VLSI 1 and embedded software is a plus

Andreas Horat, ETL H14, horat@ams.ee.ethz.ch

Prof. Dr. Christian Franck

Bachelor Project / Semester Project / Master Thesis

Circuit simulation and mathematical analysis demonstrate that this isolated Y-rectifier with a DCX-like operation (iYRX), maintains a constant output voltage with a fixed voltage ratio relative to the threephase grid voltage input. Unlike conventional designs, it achieves this with a threephase grid input, sustaining natural ohmic mains behavior without requiring active control. This simplicity promises a robust design; however, preliminary investigations reveal a significant sensitivity to asymmetries in the transformer leakage inductances caused by manufacturing imperfections. To address this, transformers will be designed and fabricated with precisely tuned leakage inductances using low-variability manufacturing techniques, such as PCB windings. These transformers will then be integrated into either an existing or newly developed hardware design, depending on the project timeline. Finally, system commissioning will enable measurements and waveform captures to validate the iYRX's operating principles.

- 20% transformer analysis and design - 45% hardware & software realization - 20% measurements - 15% report & documentation

- Lectures in power electronic systems - Interest in hardware design - Initial hardware experience is a plus

Sven Weihe, ETL H18.1, weihe@ams.ee.ethz.ch

Prof. Ch. Franck

Bachelor Project / Semester Project / Master Thesis

In the pursuit of lightweight and compact power conversion systems for next-generation aerospace applications, cryogenic cooling presents a promising approach: if cooled down to 70…80 K, the electrical conductivity of materials like copper and the performance of semiconductors improve significantly. This leads to reduced conduction losses and potentially smaller and lighter power electronic systems. To evaluate these benefits in a controlled lab environment, a reliable and safe cryogenic test setup is essential. The goal of this project is to develop and validate a cryogenic test platform suitable for characterizing power electronic systems components in a vacuum cryostat using pressure-free LN2 cooling for enhanced power extraction capability. Initially, you will use evaluate different concepts using computer simulation. Then, you will design and implement a test setup capable of maintaining and monitoring cryogenic conditions, with a focus on safety, thermal stability, and ease of integration with electrical test equipment. Finally, you will experimentally verify the setup regarding the cooling performance, thermal isolation and system stability.

- 10% literature review - 30% simulation - 50% hardware design and realization - 10% report & documentation

- Interest in power electronic systems - Interest in hardware design - Initial hardware experience is a plus

Luc Imperiali, ETL H 18.1, imperiali@ams.ee.ethz.ch

Prof. Dr. Ch. Franck

Semester Project / Master Thesis

PFC rectifiers supplying a standard dc bus for one or several variable speed motor drives from a single-phase grid are required to feature galvanic isolation to enable a flexible grounding of the inverters and bidirectional power flow to facilitate regenerative braking of the motors. A standard approach to generate such an isolated dc bus voltage is a two-stage system, i.e., a PFC rectifier followed by a high-frequency (HF) isolated dc-dc converter which, however, suffers from high realization effort and component count, and the fact that the power is converted twice. Current research therefore aims at identifying new single-phase HF-isolated PFC rectifiers with low component count and low complexity. In this project, a new converter concept is investigated in detail and a state-of-the-art prototype is designed and commissioned. In a first step simulations are conducted, and the main power component stresses are derived. Then, suitable component realizations are identified, and the PCB is designed using Altium. Further, the prototype is assembled and commissioned step by step.

- 20% circuit simulation - 50% hardware realization - 20% measurements - 10% report & documentation

- Lectures in power electronic systems - Interest in hardware design - Initial hardware experience is a plus

Rahel Herzog, ETL H 17, herzog@ams.ee.ethz.ch

Prof. Dr. Ch. Franck

Semester Project / Master Thesis

On-Board Chargers (OBCs) comprising an ac-dc PFC rectifier front-end and a subsequent isolated dc-dc converter stage represent a crucial component of Electric Vehicles (EVs), and must be able to charge the EV battery from both, a three-phase and a single-phase mains. The Smart-dc- Link (S-Link) concept facilitates compact OBCs by utilizing an active power pulsation buffer (PPB) circuit to eliminate the bulky electrolytic capacitors conventionally required for buffering the 100 Hz power ripple in single-phase operation. Advantageously, the S-Link concept employs the same circuitry also in three-phase operation to achieve a substantial reduction of the switching losses. In this project, you will first familiarize yourself with the S-Link concept and the existing hardware demonstrator. Then, you will design, tune and implement the control algorithms in a Xilinx Zynq SoC and then commission the entire S-Link hardware demonstrator, which finally facilitates the detailed experimental characterization of the system efficiency in single-phase and three-phase operation. This project is ideal for developing the skills to implement advanced control methods in a hardware prototype and to develop a good understanding of the challenges of operating both, a three-phase and a single-phase PFC rectifier.

- 20% circuit simulation & control design - 50% firmware development & commissioning - 20% measurements - 10% report & documentation

- Lectures in power electronic systems - Interest in coding and control - Experience with Zynq SOC or similar FPGA hardware is a requirement

Sven Weihe, ETL H 18.1, weihe@ams.ee.ethz.ch

Prof. Dr. Ch. Franck

Semester Project / Master Thesis

The above approach has been validated, but to enhance usability, a new testing platform with PCBs, including a logic board with a microcontroller to provide gate signals and driver supply voltages to a swappable half-bridge daughter card should be further upgraded and its functionality validated. Testing new semiconductor devices will then require only a new daughter card, with a template PCB for SiC and GaN devices to be generated as part of the project. Additionally, the temperature measurement board should be improved for robustness against electromagnetic interference from the halfbridge switching. A MATLAB script will enable automated measurement by controlling hardware to adjust gate signals, reconfigure the circuit with relays, manage supply voltage/current to the half-bridge, and capture temperature and current data to evaluate switching losses of the device under test.

- 10% error analysis and operating principal investigation - 55% hardware & software realization - 20% measurements - 15% report & documentation

- Lectures in power electronic systems - Interest in hardware design - Initial hardware experience is a requirement

Sven Weihe, ETL H 18.1, weihe@ams.ee.ethz.ch

Prof. Dr. Ch. Franck

Bachelor Project / Semester Project

A highly integrated motor drive IC was developed by Texas Instruments. This IC integrates a sensor-less permanent magnet synchronous motor controller. It automatically determines the motor parameters and can operate the motor standalone at a commanded speed. To configure and read out the machine, a microcontroller from the STM32 family with an integrated USB interface is used. The scope of this thesis is to develop the embedded software necessary to configure the TI IC via USB and to log data onto the connected SD card. In addition, a tool for the PC shall be developed to simplify the configuration concept. The converter shall then be used to characterize a dual stage blood pump machine prototype at various operating points. A simple casing shall be developed and manufactured to simplify usage in a medical environment.

- 20% literature - 50% embedded and PC software development - 20% measurements - 10% report & documentation

Lectures in power electronic systems

Andreas Horat, ETL H 14, horat@ams.ee.ethz.ch

Prof. Dr. Chr. Franck

Bachelor Project

Currently, mainly commercial FEM tools are used in the Advanced Mechatronic Systems Group. The goal of this thesis is to evaluate the open-source software Elmer FEM in the application for an implantable blood pump. In the first step, the 3D model is built and meshed. The electromagnetic machine properties shall be analyzed and compared to an existing FEM model solved with a commercial tool. In a second step, the thermal behavior of the machine shall be simulated to confirm sufficiently low blood and tissue heating. During the work, the workflow differences between commercial and open-source tools should be outlined and documented. In the end, a comprehensively documented example model for Elmer should result.

- 10% literature review - 80% FEM simulation - 10% report & documentation

- Lecture in FEM analysis is a plus

Andreas Horat, ETL H 14, horat@ams.ee.ethz.ch

Prof. Dr. Ch. Franck

Bachelor Project / Semester Project / Master Thesis

With the aim of achieving net-zero greenhouse gas emissions by 2050 and recognizing the finite availability of natural resources, future power electronic converter designs must be compatible with a circular economy. To achieve this goal, future converters must be designed for ease of repair and for ease of (partial) reuse and/or recycling at the end of life. Disassembling of electronic components is a challenge, thus it is of key importance that the end-of-life phase is already considered in the design phase. In contrast to today’s often highly integrated power converters stands a fully modular approach which enhances repairability, as defective submodules and/or components can easily be replaced, and further simplifies disassembly, such that certain long-living components can be reused again. In this project, you will familiarize yourself with circular economy concepts and the repairability, reusability and recyclability of power electronic converters. You will then study what criteria for modularization, e.g., functional, lifetime, component values, etc. is most suitable to design such a circular economy friendly converter. Then you will design and realize a 2.5 kW VSD prototype to experimentally verify your findings.

- 10% literature review, circuit simulation - 40% hardware design and optimization - 40% hardware realization - 10% report & documentation

- Lectures in power electronic systems - Interest in hardware design - Initial hardware experience is a plus

Luc Imperiali, ETL H 18.1, imperiali@ams.ee.ethz.ch

Prof. Dr. Ch. Fanck

Bachelor Project / Semester Project / Master Thesis

Due to stringent weight requirements, future all-electric aircraft may utilize a hybrid electric propulsion system. A hydrogen fuel cell (FC) provides high energy density and a battery the peak power for take-off and climbing. As the FC and the battery voltages vary in large overlapping ranges, a dc-dc converter with buck-boost capability is needed. Liquid hydrogen is stored at cryogenic temperatures, which allows to cool parts of the powertrain accordingly. For example, the conductivity of copper increases by about a factor of 10 at 77 K, reducing conduction losses in, e.g., magnetic components, and hence enables potentially smaller, lighter, and more efficient converter systems. In this thesis, you will clarify the limits of gravimetric power density of a cryogenic buck-boost dc-dc converter by means of a multi-objective optimization (MOO). First, you will familiarize yourself with cryogenic power electronics and an MOO framework. Based on the optimization results, you will design and realize a 15 kW buckboost dc-dc converter to experimentally verify your findings in a cryogenic environment.

- 20% literature review, circuit simulation - 20% multi-objective optimization (MATLAB) - 50% hardware design and realization - 10% report & documentation

- Lectures in power electronic systems - Interest in hardware design - Initial hardware experience is a plus

Luc Imperiali, ETL H18.1,imperiali@ams.ee.ethz.ch

Prof. Dr. Ch. Franck