System-level design and stability analysis of DC microgrid

DC microgrid will be the main power supply system for the future sustainable homes and buildings due to the advantages of the low converter cost and easy control with no reactive power concern. The system-level stability is an important issue in the design of the DC power supply system. The overlap between the output impedance of paralleled converter and load input impedance causes the system instability. This paper presents the output impedance designed for the paralleled converter in DC microgrid and analyzes the output impedance peak of the paralleled converter which worked in droop control method. The impacts of the line filter parameters on the system stability are also discussed. Simulation results show that they are confirmed fitting the stability criterion in a simple DC microgrid.