I. Introduction
An increasing number of grid-tied pulsewidth modulation (PWM) interfacing converters have been integrated into modern power systems for many applications including active-front end of variable frequency drive, distribution generation (DG), grid-interactive energy storage, and power conditionings in [1] and [2]. With high penetration level of power electronic converters, the control of grid-tied converter becomes more challenging due to a few major issues such as control loops interaction, protection interferences, and the power quality problems.