Study and Implementation of a Selective Detection of Harmonics using a PLL-Based Algorithm

Power electronic loads are sources of unwanted harmonic as well as reactive power. Passive power filters and active power filters are a suitable solution for those power quality issues. If active power filters are used, then it controls systems need to measure of harmonic and reactive power to compensate it through a controlled current or voltage source. Thus, it is important to determinate both, fundamental component and harmonics components for the electric variable to be compensated. Furthermore, if the design uses a modular approach with several active filters compensating different harmonics then the value of each harmonic in real time is required. This work presents a method to find the harmonic components of signal based on a robust PLL where a sinusoidal base is built and used to find the Fourier coefficients for the selected harmonics. Simulated and experimental results are presented to validate the theoretical considerations.