State observer for grid-voltage sensorless control of a grid-connected converter equipped with an LCL filter

This paper proposes a simple grid-voltage sensorless alternative to the conventional PLL synchronization for a grid-connected converter equipped with an LCL filter. The grid-voltage magnitude and angle are estimated based only on the converter current and DC-voltage measurements. Reduced number of sensors decreases costs and amount of sensor wiring. The analytically derived design is validated experimentally.