This paper proposes a new integrated self-synchronising stationary frame current control strategy for grid-connected converters. The strategy uses quadrature outputs from the stationary frame current controller resonator to create self-synchronised target current references, and then uses the current errors as inputs to a frequency locked loop to track grid frequency variations without requiring any external measurements. The resultant system maintains accurate current regulation and excellent fundamental frequency synchronisation, even under varying and distorted grid conditions. The effectiveness of the approach has been verified using detailed simulation and experimental investigations.
