Large signal stabilization method of constant power loads by adding R parallel damping filters

In the DC power systems of More Electric Aircraft, the closed-loop controlled electrical motor drives and power electronic converters can be generally regarded as constant power loads (CPLs), and usually lead to negative impedance-related instability. Depending on Brayton-Moser´s mixed potential theory, this paper adopts R parallel damping filters to stabilize the CPLs systems, and derives large signal stability criteria. The simple criteria utilize the dynamic negative impedance of the CPLs to place quantitative constraints on the filter parameters, and provide important design guidelines during the filter determination. Comparisons demonstrate the stability criterion for the CPLs with a single-stage LC filter can be regarded as a special case of the proposed criteria. The region of asymptotic stability (RAS) around the stable equilibrium point is obtained, and it indicates the criteria can guarantee the system stability during large disturbances. The experimental results also confirm the validity of the proposed stabilization method.