Performance Comparison of a Dynamic Voltage Restorer Using DQ and PQ Control Methods

In the dominion of power systems, voltage sags and swells are transient disturbances that can significantly impact the performance and stability of the grid. This issue must be addressed with robust control techniques to have good performance, with low harmonic and stable operation of the power system. Many techniques for instance, dynamic voltage restorers (DVRs) and series active power filters were proposed based on conventional theories having merits and demerits. This research aims to provide a comprehensive comparison between two DVR control techniques. The First technique is the modified instantaneous reactive power theory (PQ), whereas the second is modified synchronous stationary frame (DQ) method under various sag and swell voltage conditions. The extracted components of the grid voltage positive sequence and load current negative sequence form the basis of the improved approaches. to detect the disturbance and generate the control signal of the DVR. The study encompasses Unbalanced load voltage with 80% sag, unbalanced load voltage with 70% swell, balanced 80% voltage sag, and a 50% balanced load change are the four different operating conditions. Both control approaches, with their modified versions, are mathematically represented and evaluated under different specified severe power quality conditions. The methods are performed in MATLAB/Simulink environment and implemented experimentally using DSPACE DS1104 controller-based system to provide a comparison analysis and validate the system's voltage profile and harmonic distortion performance study. The obtained results and analysis illustrate the effectiveness of the proposed two control methods. Each technique demonstrates their effectiveness for addressing the power quality issue.