ÇUKUROVA UNIVERSITY INSTITUTE OF NATURAL AND APPLIED ...

3. FUNDAMENTALS OF DVR Mustafa İNCİ
Figure 3.15. Phasor diagram of the phase advance compensation method
In this method the values of load current and voltage are fixed in the system
so one can change only the phase of the sag voltage. In short, PAC method uses only
reactive power and unfortunately, not all the sags can be mitigated without real
power, as a consequence, this method is only suitable for a limited sag range (Shazly
et al., 2013).
3.3.4. Reference Voltage Generation
Reference signals are generated using time domain and frequency domain
methods in literature. Frequency domain methods use Fourier Transform (FT) to
generate reference signals. Even though it enables selective harmonic elimination
and provides to generate reference signals rapidly, it has main drawbacks such as
requirement at least one cycle to estimate the reference current and control
complexity compared to control methods in time domain. Synchronous Reference
Frame (SRF) and P-q-r (IRPT) are the most common and popular control techniques
to determine the reference signals based on time-domain. RMS (Average) Magnitude
Detector, Recursive Weighted Least Square Method, Modified Delta Rule Method,
Kalman Filter, EPLL are another methods to generate reference voltages in dynamic
voltage restorer. Besides, SOGIPLL is performed and analyzed to extract reference
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