Energy-based Stabilizing Controllers for DC-DC Converters Feeding Constant Power Loads

In this paper is studied and presented the solution for the instability problem caused by the interconnection of DC converters with constant power loads (CPLs). A linear and a nonlinear energy-based approaches are proposed. Without the presence of CPLs, the stability of the DC-DC power converter is intrinsic, while with CPLs the stability must be induced, a task that is not easy with traditional control approaches. This paper shows that the stabilization of the power converter can be achieved in pure physical terms, using power and energy as the primary objectives, which can be done in a linear and a nonlinear approach. Also, considering the energy as the perspective for the problem provides a physical explanation to the stability issues, furthermore, it provides a clear practical solution, because now it is possible to link the parameters of the controller to nominal specifications that are used for power converter design. In this way, the strategies based on the power and energy are now based on known approaches, which is a difference to known approaches, whose stability are based on frequency domain, eigenvalue and immittance criteria. Experimental results are presented to corroborate the theoretical analysis.