Linearized large signal modeling, analysis, and control design of phase-controlled series-parallel resonant converters using state feedback

This paper proposes a linearized large signal state-space model for the fixed-frequency phase-controlled series-parallel resonant converter. The proposed model utilizes state feedback of the output filter inductor current to perform linearization. The model combines multiple-frequency and average state-space modeling techniques to generate an aggregate model with dc state variables that are relatively easier to control and slower than the fast resonant tank dynamics. The main objective of the linearized model is to provide a linear representation of the converter behavior under large signal variation which is suitable for faster simulation and large signal estimation/calculation of the converter state variables. The model also provides insight into converter dynamics as well as a simplified reduced order transfer function for PI closed-loop design. Experimental and simulation results from a detailed switched converter model are compared with the proposed state-space model output to verify its accuracy and robustness

A methodology for cooperation between electric utilities and consumers for microgrid utilization based on a systems engineering approach

In recent years, the energy market has experienced important challenges in its structure and requirements of its actors, such as the necessity for more reliable electric service, energy efficiency, environmental care practices, and the incorporation of decentralized power generation based on distributed energy resources (DER). Given this context, microgrids offer several advantages to the grid and its actors. However, few microgrid projects have been implemented, and the participation of electric utilities is lower than the expected. Hence, this research explores how electric utility - customer interactions can accommodate mutual benefits for both parties through the proposal of a Microgrid Reference Methodology (MRM) that guides the cooperation of these actors for future microgrid projects. For this research, an understanding of the microgrid system was imperative; hence, the interests and concerns of electric utilities and industrial customers were determined via questionnaires, interviews, and a literature review of specialized articles, books, and magazines. In addition, the MRM development was based on different frameworks and concepts from the fields of Systems Engineering, System of Systems, Management Science, and Infrastructure Architectures. The proposed MRM uses a four-level microgrid system in which the delta (business) level is added to the other three levels that are traditionally analyzed in microgrid design and modeling. The steps and processes necessary to determine the actors in the system and their interests, goals, criteria, and factors are exemplified with a generic case study, in which the proposed MRM evaluates the impact of different alternatives on the objectives of both parties. In addition, it was possible to identify external factors that can be influenced by other actors, such as regulators and government, to incentivize the implementation of microgrid projects