Projektarbeit

Classical modulation technique for power inverters use the triangular carrier signal modulation or the space vector modulation to generate the voltage pulse patterns. In general, these resulting voltage pulse patterns are non-optimal in view of the total harmonic distortion (THD) of the voltage pattern itself, but also non-optimal in view of the resulting current, even in steady state synchronized operation.

Because the voltage pulse patterns and the resulting currents are periodic in the steady state operation, the main tool for the analysis of the charactersitics is the Fourier series expansion. Therefore, the Fourier series expansion of the volage pattern can be used to analyse the spectral characteristics of the voltage pulse pattern, the THD of it and the THD of the resulting current.

This project aims to investgate the analytical description of different voltage pulse patterns in steady state operation of the power inverters. At first, voltage pulse patterns with quarter wave symmetry will be investigated, taking different numbers of pulses per half period into account. Secondly, pulse patterns with half wave symmetry will be constructed and analysed in view of their characteristics. Both types of pulse patterns with different numbers of pulses should be optimised to reach to least THD of the resulting current in different operation point, depending on the modulation index.

Besides single phase inverters, three phase inverters should be considered in the investigation. The power inverter switches will be modeled as ideal switches. The SicLab software environment will be used for building up the simulation models and to perform the analytic-numerical analyses. Theoretical derivations, the general and detailed findings and the developed software should be commented and documented precisely and in detail.

PA 001

Auskunft und Betreuung: Prof. Dr.-Ing. Ingo Hahn