Real-time Amplitude and Phase Detection of Grid Fundamental Voltage Considering Decaying DC Component

The fast and accurate fundamental-wave amplitude and phase detection of the grid voltage can be realized by filtering the decayed DC (DDC) component signal effectively. To this end, firstly, based on the periodicity and half-wave symmetry of the three-phase grid voltage signals, the grid voltage is sampled at a half-period and full-period delay under the abc frame system to achieve the DDC component detection in one grid-period. Secondly, aiming at the distorted signals containing both DDC and harmonic components, the DDC detection algorithm and the moving average filtering algorithm are combined in the dq frame system to achieve the simultaneous filtering of DDC and harmonic components in one grid cycle. Finally, the proposed detection algorithm is combined with the grid voltage amplitude/phase detection algorithm to obtain a complete amplitude phase detection algorithm for the fundamental grid voltage. Experiment results verified the effectiveness and advancement of the proposed detection algorithm.