| Title |
The Study on Detecting Scheme of Voltage Sag using the Two Difference Voltage |
| DOI |
http://dx.doi.org/10.5207/JIEIE.2014.28.12.065 |
| Keywords |
All-Pass Filter(APF) ; Two Difference Voltage ; Zero Crossing Voltage |
| Abstract |
In this paper, the detection scheme of the voltage variation using a two difference voltage is proposed. The conventional sag detector is from a single-phase digital phase-locked loop (DPLL) that is based on a d-q transformation using an all-pass filter (APF). The APF generates a virtual q-axis voltage component with 90° phase delay but the APF cannot generate the virtual q-axis voltage depending on the phase of the grid voltage. To overcome the problem, q-axis voltage component is generated from difference between the current and previous value of d-axis voltage component in the stationary reference frame. However, the difference voltage around the zero crossing is not enough to detect the voltage sag. Therefore, the new detection scheme using the two difference voltage which can detect the sag around the zero crossing voltage is proposed. |