Sinusoidal Amplitude Integrator-based Harmonic Extraction for Active Harmonic Filter

The substantial increase in demand has also posed a threat to utilities due to nonlinear loads. A recent example is the cluster of EV charging stations with a front-stage rectifier unit followed by passive LC filtering to generate the DC link. These practices lead to power quality issues in the grid because of the nonlinear current extraction. To address these challenges, this paper proposes an Active Harmonic Filter (AHF) incorporating a Sinusoidal Amplitude Integrator (SAI) for harmonic extraction. AHF injects the high-harmonic current components into the Point of Common Coupling (PCC). Thus, the source current is drawn to be of acceptable quality. Traditionally, in synchronous reference frame control techniques, harmonic currents in the grid current are extracted through a low-pass filter. Unbalances in the voltages can lead to synchronization issues and potentially slow down the detection of harmonic currents. Fast and precise harmonic detection can be achieved using SAl-based harmonic detection. The instantaneous power theory-based Phase-Locked Loop (PLL) is implemented to achieve seamless and reliable synchronization. Simulations and experiments are carried out to verify the proposed control.