Analysis of Synchronverter and PLL-Less Control for Three-Phase VSI in AC Microgrids

To ensure optimal performance at the Point of Common Coupling (PCC) within grid-tied micro grids, efficient inverter control techniques are essential. The primary aim of this study is to conduct a comparative analysis between the synchronverter and PLL-less based Grid Voltage Modulated Direct Power Control (GVM-DPC) techniques for inverter regulation. The paper includes the mathematical modeling of these control methodologies. To regulate the gate pulse of the Voltage Source Inverter (VSI), the Sine Pulse Width Modulation (SPWM) technique is adopted. The controller's performance and resilience are evaluated in both stable and dynamic conditions, particularly concerning variations in available active
$(P_{ref})$
and reactive
$(Q_{n}\lambda$
powers at the DC end. The developed simulation model is executed in the MATLAB/ Simulink environment to validate the effectiveness of the controllers. In the synchronverter method, the modulating signals are obtained directly from the instantaneous grid voltages, which are derived from the necessary mechanical input and induced EMF. The PLL-less GVM-DPC control exhibits a rapid response in the aspect of power fluctuations or transients, surpassing the performance of the synchronverter control.