Online Bus Impedance Estimation and Stabilization of DC Power Distribution Systems: A Method Based on Source Converter Loop-Gain Measurement

In this work a method of stability monitoring and adaptive stabilization is proposed for DC power distribution systems (PDS). It has been shown that the stability of DC PDS can be effectively analyzed using the system bus impedance, which is calculated as the parallel combination of all individual impedances of the converters connected to the DC bus. Conventionally, these impedances are measured in several lengthy measurements. This work, instead, proposes a method for online estimation of the bus impedance using the voltage loop-gain of the source converter and the input impedance of the load converter. In this approach, all the needed information for system stability monitoring and adaptive stabilization are obtained in a single measurement by injecting a wide-band perturbation in the source converter control platform. This method has several advantages, namely the simplification of online stability monitoring and stabilization as well as elimination of the need for any communications among converters. The proposed method is validated by simulation and experimental results.