Low-cost input impedance estimator of Dc-to-Dc converters for designing the control loop in cascaded converters

Current trends in power distribution systems are focused on distributed architectures instead of centralized approach. Distributed architectures are more complex since a network of power electronic converters is required to distribute power with appropriate performance. One of the main issues deals with the control loop design of the converters when they are loaded by other converters downstream. Existing design approaches of the converter control loop for system-level stability are typically based on the use of small-signal impedance-based models of the different converters. As a consequence the input impedance of the converters that act as load is required to design the feedback compensation. However, these systems are usually comprised of subsystems made up by a variety of manufacturers, which do not provide the data required to parameterize a model due to reasons of confidentiality. Hence, many power system designers should perform complex measurements and identification techniques to obtain behavioral models of the converters to perform proper control loop design. The aim of this paper is to provide an input impedance estimator of the Dc-to-Dc converters avoiding complex power system measurements and analytical identification techniques. The proposed estimator has been validated with several commercial converters provided by different manufacturers.