<p>LCL filters are widely employed to enhance the current quality between power converters and the grid due to their superior harmonic attenuation capability. However, they have a resonance issue at specific frequencies where the impedance drops to zero, necessitating appropriate damping techniques. Passive damping using resistors leads to power loss, while active damping methods employing virtual resistors and compensators typically require additional sensors. To overcome these drawbacks, an active damping method based on a model reference adaptive system (MRAS) observer, which is implementable without extra sensors, has been proposed and shown to be effective. However, a mathematical and quantitative evaluation of its performance has not been carried out. This paper presents a performance evaluation of MRAS based active damping through system modeling and proposes a novel virtual resistor based active damping scheme utilizing the MRAS observer.</p>