Grid Voltage Sensorless Control of Three-Phase LCL Grid-Connected Inverters Using Multisampled Current

This paper presents a grid voltage sensorless control strategy for three-phase LCL-type grid-connected inverters by only using inverter current. The capacitor voltage is estimated based on linear regression of the multisampled current during zero voltage vectors, which is used for the grid synchronization in a phase-locked loop (PLL). Single-loop control with inverter current feedback is employed because the multisampling can reduce control delays and extend the stability range. Moreover, based on the fast response of multisampling control, the inverter current feedforward is utilized to compensate the impact of the grid on the inrush current. Finally, the effectiveness of the proposed method is verified through the simulation.