Simulation and Testing of a Power Converter for Aircraft AC Electric Power Generation System using Software Elimination of Higher Harmonics

Abstract

This paper presents the results of simulation and practical tests of the inverter-based power converter with a sine output filter designed for implementation in an aircraft power system. In order to reduce the output voltage harmonic distortion, the converter utilises active software harmonics filtering. This work provides an analysis of the converter performance under two control algorithms applied for the active filtering operation. The first control algorithm is based on discrete Fourier transform (DFT) where the control system injects measured higher harmonics with inverse polarity into the inverter command voltage and DFT provides the measurement of the converter output voltage. The second control method is based on repetitive controller (RC) algorithms which adjusts the inverter command voltage using a self-learning approach. The second method significantly reduces the demand for CPU computational resources. The software filtering in both systems shows a good performance and ensures the converter output voltage with less than 5% THD under all load conditions. This paper discusses the structures for both proposed control systems as well as the implementation in MATLAB models and microcontroller software. Both algorithms are modelled in software and implemented in a practical microcontroller. The advantages of the RC-based control method are demonstrated through the software analysis and performance of the system.

Equivalent Electrical Model of an Inductor Excited by a Triangular Current Including Saturation

“…These components have non-linear behaviour that needs to be added in electromagnetic analysis to develop a transient simulation of these power converters [7][8][9][10][11]. Models of these magnetic components can be found in the bibliography [12][13][14], However, non-linear models that represent non-linear behaviour is an an absence of power converterfield. An electrical-magnetic model of a ferrite inductor valid for triangular current excitations is presented for a 15 kHz to 1 GHz frequency range (the range of switching frequencies used by power electronic converters based on Si, SiC or GaN semiconductors) with different signals to include the saturation status in the analysis.…”