A Novel Active Stabilizer Method for DC/DC Power Converter Systems Feeding Constant Power Loads

Multi-converter DC power distribution systems are widely used in different applications such as electric vehicles, more electric aircraft, and modern ships. In these systems, addressing the instability problems induced by constant power loads (CPLs) due to their negative incremental impedance characteristic has become an interesting research topic. Hence, in this paper, firstly, the stability of a DC/DC buck power converter system loaded by a CPL is analyzed through the system's state-space averaging model, and then, its stability conditions are identified. Afterward, in order to overcome the destabilizing effect caused by the CPL, implementation of a novel active stabilizer scheme is presented. Using the proposed stabilizer technique, which has a simple control structure with a more straightforward tuning of control parameters, the system stability is guaranteed without affecting the dynamic performance of the system. This result is achieved by insertion of a virtual series RC in parallel with the output LC filter capacitor for satisfying the system stability criterion. In addition, practical constraints such as weight saving and low power dissipation are preserved, which are critical factors for the embedded DC power distribution systems. The circuit physical meaning realized by the proposed active stabilizer scheme is analytically proved. Simulation results are also provided to verify the effectiveness of the presented stabilizer.