Addressing Stability Limits of a LVDC Shipboard Microgrid with CPL via Impedance-Based Approach

DC shipboard microgrids operate in islanded mode, making voltage regulation performance crucial for system stability. The presence of constant power loads, such as electric propulsion, introduces negative incremental resistance, which can affect stability. This work presents an impedance-based modeling and stability analysis of a LVDC shipboard microgrid. The impedance characteristics of system components are derived, and stability is evaluated based on source-load interactions. The Nyquist criterion is applied under various load conditions to identify stability limits and assess the influence of constant power loads and constant resistance loads. The methodology highlights the destabilizing effect of the constant power load and the damping effect of constant resistance load, providing insights into the dynamic behavior of the microgrid. Electromagnetic transient simulation results validate the proposed approach.