Implementation of a D-STATCOM and Active Power Filter Control Strategy–Based on Virtual Flux Direct Power Control Technique for an Electrical Energy Quality Improvement

The improved virtual flux–based direct power control (VF-DPC) strategy for a grid-connected power converters is proposed in this paper to eliminate current harmonics and mitigate voltage fluctuations during grid voltage faults without using voltage sensors. The proposed control strategy integrates VF-DPC for static reactive power compensator (STATCOM) and active power filter (APF) into a single algorithm. The reference electrical quantities for each operating mode of the converter are selected based on the state of the electrical grid. Specifically, if the grid voltage variation remains within the limits defined by international standards, the APF operating mode is prioritized. However, if the voltage variation exceeds these standards, the STATCOM operating mode is given preference. The primary goal of the proposed control strategy is to enable a seamless transition between APF mode and STATCOM mode, while minimizing reactive power exchange with the electrical grid and reduces the number of sensors required. This control strategy gives priority to the reactive power injection during grid voltage faults to support voltage regulation. Under normal grid conditions, it enables the power converter to effectively eliminate current harmonics produced by nonlinear loads. Simulation results demonstrate that the proposed modified VF-DPC technique has high performance in both of converter operation modes. Practical results plotted using a test bench based on a dSPACE 1104 card justify the validity and efficiency of the developed algorithm.