Open student theses
Due to ever increasing power densities, number of devices and the use of wide-bandgap semiconductors, power electronic systems are getting more complex and compact. To still achieve a maximum efficiency, all solutions of the (discrete) solution space must be investigated. The solution space is defined by e.g. suitable semiconductors and passives or the PCB-design.
To map this solution space, the aid of computer-based methods is necessary, which are calculating the optimal point of the so called pareto-front.
Goal of this thesis is to implement a workflow for such a pareto-front optimization with a multi-dimensional simulation for a compact DC/DC-converter and, if applicable, to construct and characterize this converter.
- Literature research (10%)
- Implementation multi-domain optimization (50%)
- Setup and characterization of the converter (25%)
- Written thesis & talk (20%)
- Experience in 3D-FEM helpful
- Knowledge in power electronics
- Good knowledge of MATLAB or similar
ILH takes part at the international MTT Sat-Challenge for students and after-graduates, with the goal of the development of novel high-frequency hardware (RF) for CubeSats. The ILH convinced with the idea of combining a gallium nitride (GaN) power amplifier for W-band (75-100 GHz) with a variable and monolithic integrated GaN DC/DC power supply, to achieve a more compact and efficient amplifier.
In addition the amplifier should be improved by digital pre-distortion and with the aid of a power detector at the output of the amplifier, an intelligent power module should be evaluated.
The ILH is offering several topics for a student thesis in the frame of this challenge:
- Layout design and simulation of an integrated DC/DC converter
- Reduction of noise of a GaN DC/DC for a SSPA supply
- Control implementation for a GaN DC/DC on a space-ready micro-controller
- Simulation and layout of a power detector topologies incl. couplers in a GaN-technology
- Implementing and extension of digital pre-distortion for an E-band amplifier
- Investigation of efficiency enhancement methods for a power amplifier in E-Band
- Investigation of analog pre-distortion technologies for a mmW amplifier
- Influence of noise in the DC supply on a mmW amplifier
One of the main objectives in the development of power electronic circuits is to increase efficiency and thus reduce energy losses. This allows a smaller dimensioned cooling system and reduced space requirement of components, which leads to material savings and in the end to cost reduction and a resource-saving production of the power electronic assembly.
The topic of this thesis is to identify the limits in which Peltier elements in power electronic circuits can be usefully applied for energy recovery.
In this context it has to be investigated under which electrical and thermal conditions the Peltier element has to be operated, at which point in the heat dissipation path it can be best integrated and how the generated electrical energy can be coupled into the circuit of the gate control.
- Peltier elements:
- Simulation capabilities
- Energy recovery with TEGs
- Losses in gate driver circuits
- Possibility of energy recovery into the gate driver circuit
- Circuit design for efficiency analysis
In high-frequent switching converter passive components (inductances, capacitances and transformers) are playing a major role, since their losses are often higher than the ones from the active components. Especially the estimation of these losses is difficult, since there is no efficient method to characterize the losses at high frequencies. Also the modelling of core materials at high frequencies and a wide power area is complex.
Because of these reasons in this work a design-flow should be developed, which allows to simulate and model inductances and transformers. In a first step different physical models (e.g. litz-wire) should be connected with magnetostatic and full-wave simulations. Afterwards a conventional transformer should be simulated and with the gained experience a planar transformer should be designed and optimized. If necessary some measurements with a NWA will support the simulations.
- Familiarization & literature search(10 %)
- Simulation and modelling of a transformer (25 %)
- Design and simulation of a planar transformer (25 %)
- Measurement of transformer (optional 20 %)
- Written thesis & presentation (20 %)
- 3D-FEM simulation in CST
- Knowledge of magnetic components and their loss mechanisms
- Practical experience