Large signal stability analysis for constant power loads with RC parallel damping filters

In the DC power systems of advanced aircraft, the electrical motor drives and power electronic converters generally behave as constant power loads (CPLs) when tightly regulated, and usually cause negative impedance instability. This paper introduces RC parallel damping filters to stabilize the CPLs systems, and derives large signal stability criteria for the CPLs based on Brayton-Moser´s mixed potential theory. The simple criteria utilize the dynamic negative incremental impedance of the CPLs to place quantitative constraints on the filter parameters. Comparisons indicate the stability criterion for the CPLs with a single-stage LC filter can be regarded as a special case of the proposed stability criteria. Simulation and experimental results confirm the presented criteria would guarantee the system stability under different voltage disturbances.