Study of Control Strategies for Grid-connected Current Improvement Under Distorted Grid Conditions Based on Virtual Impedance

Addressing the situation where the power grid voltage contains harmonic voltages causing distortion in the inverter’s current through the grid, this study begins by analyzing the procedure of harmonics production in the output currents of voltage source inverters using a voltage-current dual-loop control diagram. Subsequently, recommending a current enhancement technique for the grid. In order to reconstruct the line impedance, this is accomplished by feeding the voltage across the virtual impedance returned into the dual-loop control, thereby achieving harmonic current suppression. Finally, the correctness of the research methodology was demonstrated through simulation results.