Modelado y control predictivo de un convertidor NPC de 5 niveles

Abstract

I n power electronics systems, the widely applied concept of averaging, used to conceal the switching aspect from the control problem, is becoming obsolete. The motivation of this work is to replace the classic use of the current loop and modulator by one single control entity. The MPC combines the possibilities offered by a control problem with discrete states such as power electronics, together with the increasing computing power offered by the control and actuation systems today. The MPC control aims to be the basis of control within the switching power electronics, offering robust control with lower switching frequencies than modulation and low harmonic distortions. This work focuses on the use of the predominant model-based predictive control (MPC) scheme applied to elements of power electronics. Specifically, emphasis is placed on DC-AC conversion systems for medium-voltage (MV) applications. Particularly, the control strategies that are developed throughout the work will be verified on NPC multilevel converters (Neutral-Point Clamped) that operate at switching frequencies on the order of tens of KHz. The proposed control techniques are parameterized for possible applications on elements of lesser or greater power. For the verification and simulation of the control strategies that are presented in this work, there is a 12 KVA power five-level NPC bidirectional converter, which will serve as the basis for all the simulations that are made, with the intention of implementing a controller for said converter that confirms the benefits of the proposed control. For this purpose, a constructive modification in this converter is proposed for its adaptation as a DC-AC inverter.