Simulation of series active power filter with adaptive harmonic injection method

Semiconductor technology has developed rapidly in the last century, paving the way for more frequent use of power electronics elements in the field. However, due to the high frequency switching and non-linear load characteristics of these elements, power quality problems have arisen in power systems. These devices, which contain power electronics elements and are frequently used in electrical systems, have some disruptive effects on the system. The most important of these effects are harmonic generation and reactive power draw from the system. Although the use of passive filters is a traditional approach to overcome these problems; recently, active power filters have been used more frequently for harmonic filtering and reactive power compensation due to their disadvantages such as not being able to keep up with changing load conditions, being suitable for fixed compensation and most importantly resonating with the mains or load. In this thesis, a control algorithm has been proposed for the elimination of harmonics caused by problems such as voltage sag and swell on the source side and harmonic components that may occur in the source during the generation of electricity without causing any change in the load voltage. This algorithm is an Adaptive Harmonic Injection (AHI) algorithm based on the Normalized Least Squares (NLS) method. The algorithm is an adaptive reference mark generation algorithm that can be implemented in the time domain. The circuit topology in which the algorithm is applied is a 3-phase, 3-wire Series Active Power Filter structure created using a Voltage Source Inverter (VSI). The aim here is to switch the VSI of the estimated reference signals obtained by the AHI algorithm and to ensure that the harmonic to be printed on the system is detected correctly. Space Vector PWM (SVPWM) is used to obtain the switching signals at the VSI input and the system is simulated using the Matlab2021a/Simulink interface. According to the results obtained, it is evaluated whether the THD (Total Harmonic Distortion) values are within acceptable limits. The results obtained from this study show that the proposed AHI algorithm is a very successful method in eliminating voltage harmonics.