Power quality of smart grids: study of supraharmonics (disturbing phenomena in the frequency range 2-150 kHz)

Disturbing phenomena in the frequency range 2-150kHz, known as supraharmonics are gaining more and more interest in the recent year. In this master thesis an experimental setup is built to assess the supraharmonic emissions of an Active Power Factor Corrector (APFC) circuit. The goal is to test a specific control and to asses the behaviour of the converter as a supraharmonic current or voltage source. To do so, we put an inductance in serie with the grid and measure the voltage and current at the input of the device under test for different values of the serie inductance. By looking at the 50kHz voltage and current variation in function of the serie inductance we can deduce the supraharmonic current or voltage source behaviour. We use 800Hz band grouping around the 50kHz switching frequency. This setup is composed of a Texas instrument development kit connected to an auto transformer. The TI kit is the masterpiece and permits to implement the desired control using Matlab Simulink. The complete measurement method is detailed and digital filtering is used to mitigate the side effects of the Discrete Fourier Transform (DFT). Two main measurements are presented. First the effectiveness of the APFC in reducing the low frequency harmonics (up to 2kHz) is shown. Secondly, the supraharmonic voltage source behaviour of the converter is confirmed.