Modeling and Nonlinear Control of dc–dc Converters for Microgrid Applications

Abstract

This paper proposes a high-performance control strategy for dc–dc converters supplying combined loads (constant current/power, and/or linear loads). This strategy combines a feedback law with a feedforward compensation. The feedback law is based on full feedback linearization, which guarantees that zero dynamics are avoided. To design a single controller for the three basic converter topologies (i.e., buck, boost and buck–boost), a unified model for these converters is introduced. From the resulting combined control law, the specific control law for each type of converter can be obtained by setting three constant coefficient to 0 or 1. The feedforward compensation is based on the estimated values of the load obtained via a nonlinear observer. The main advantage of this unified approach is that it is implemented by using a single algorithm which can be executed in a dedicated hardware, for instance, a single integrated circuit, providing a unified solution for the control of the mentioned topologies. The good performance of the proposed scheme is verified through simulations and tested via experimental application cases, concluding that this is a good unified solution to control dc–dc converters used in microgrid applications.