Performance analysis of second order adaptive filter using Matlab Simulink

Grid-tied distributed energy sources needs a proper synchronization technique which will estimate the phase angle of the grid voltage. The most common synchronisation techniques are being the phase locked loops (PLL)s, which decides the quality of grid utility power. By using different filtering techniques, the disturbance rejection capability in the (PLL)s can be improved. Synchronous reference frame phase locked loop (SRF-PLL) is the most commonly used synchronisation technique because of its simple operation good dynamic response. The conventional (SRF-PLL) controller with high bandwidth when used for synchronization work provides satisfactory performance when the grid voltage is undistorted and balanced. However SRF-PLL does not work properly in case of distorted and polluted grid conditions, so the estimated phase can have a substantial amount of unnecessary ripple. In case the grid voltage is balanced but polluted with higher order harmonic with reasonable amplitude, the detection system bandwidth can be reduced in order to attenuate the effect of harmonics on the output. Here second order adaptive filters (SOAF) are used to extract the harmonic components existing in balanced and polluted harmonic grid signals.