Active Damping Design with Additional Harmonic Rejection for Single-Phase Grid-Tied Inverters

This paper presents the use of an alternative control strategy for single-phase grid-tied inverters, with active damping based on virtual resistor and grid-side current feedback for the control network. The damping technique uses the converter-side inductor current feedback to provide assistance in the harmonic compensation in order to help comply with power quality standards, such as IEEE 1547 and IEC 61727. The current control structure uses proportional-resonant controller with harmonic compensation, the virtual resistor and control gains are designed to achieve stability and low harmonic distortion despite of grid parameters variance. The active damping is analyzed through mathematical modeling and computational simulation, additionally, experimental results are presented as a form to validate the theory described.