Design and Comparison of Two Control Strategies for Voltage-sag Compensation using Dynamic Voltage Restorers
Keywords: Control design, dynamic voltage restorer, power quality, voltage sag
AbstractThe Dynamic Voltage Restorer (DVR) is one of the most frequently used devices for voltage-sag compensation. This work explains the design procedure and comparison of two different control strategies for the compensation of balanced and imbalanced voltage sags by using a DVR. The two strategies considered are the widely-used proportional-integral (PI) controller and a new approach based on the generalized proportional-integral (GPI) controller. Both control schemes are implemented in a synchronous reference frame (SRF) and use a feedforward term to improve the time response. The simulations in PSCAD/EMTDC show the performance of both control strategies for several voltage sags and for grid-frequency deviations. The obtained results show that the SRF-GPI approach is superior.
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