Adaptive Line Impedance Estimation Algorithm for DC Microgrid Systems

This paper proposes a novel closed loop adaptive cable line resistance estimation method for DC Microgrid to ensure accurate load sharing and enhanced DC bus voltage regulation. The proposed method injects a small voltage perturbation to the DC bus voltage reference for a short period of time and estimates the cable line resistance value associated with the DC/DC converters in the DC Microgrid by employing a closed loop estimation algorithm. Additionally, the proposed method considers the effect of cable line inductance in the estimation procedure for making it more robust and can perform seamlessly at small perturbation levels with very small perturbation-time interval. Unlike the existing methods, the proposed method doesn't require any additional hardware circuitry or superimposed frequency to determine the cable line resistance. Detailed simulation in MATLAB/Simulink, experimental results along with comparison with the existing estimation methodologies has been presented to showcase the effectiveness of the proposed method.