Observer-Based Grid-Voltage Sensorless Synchronization and Control of a VSI-LCL tied to an Unbalanced Grid

ROBERTO FANTINO; CLAUDIO BUSADA; JORGE SOLSONA

IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

Lugar: New York; Año: 2019 vol. 66 p. 4972 - 4981

0278-0046

This work proposes an observer-based gridvoltage sensorless strategy that allows to implement the synchronization and control of an LCL grid-tied voltage source inverter. By using exclusively the measurement of the current injected to the grid, an observer estimates both fundamental positive- and negative-sequence components of the grid voltage, with a quality (in terms of THD and convergence speed) comparable to that obtained with a classic DSOGI-FLL. The unmeasured LCL filter states are also estimated by the observer, and they are used to implement a full-state feedback control strategy suitable for low resonance frequency LCL filters. The effectiveness of the scheme proposed here is demonstrated by comparison with a DSOGI-FLL and with a controller recently proposed in the literature. Experimental and simulation results that demonstrate the validity and effectiveness of the proposal are presented.