Analysis and Experimental Validation of Virtual Flux Direct Power Control Pulse Width Modulation AC–DC Converter Under Distorted and Unbalanced Voltage Supply

Virtual flux direct power control (VFDPC) is an advanced power control technique designed to effectively address the challenges posed by unbalanced and distorted voltage supply in an electrical power grid system. A key feature of VFDPC is the implementation of positive and negative sequence extraction methods within the controller to reduce the negative effects caused by unbalanced and distorted input voltage. Estimation of the instantaneous active and reactive powers is done by analyzing the positive and negative sequences of the virtual flux in the three-phase grid. By accurately extracting and compensating for the negative sequence components, the VFDPC effectively reduces current harmonics to 2.96% in simulation and 3.8% in experimental validation, ensuring optimal system operation even under challenging supply conditions. In this study, a VFDPC system was tested under unbalanced and distorted voltage supply conditions as well as under various loads and DC reference voltages to evaluate its dynamic performance. The results revealed that the VFDPC system maintained stable operation and consistent performance despite the significant changes in load conditions and DC reference voltage levels. This capability ensures that the power converter can handle sudden changes in the power demand without compromising the stability or quality of the power supply. Moreover, power factor analysis was conducted to test the VFDPC system under unity, lagging, and leading power factor operating modes. Finally, experiments were carried out to validate the simulation results for the VFDPC system under unbalanced voltage conditions, including the dynamic performance of the VFDPC system under various loads and DC reference voltages and power factor adjustments.