Model Predictive Control of Multilevel Cascaded H-Bridge Inverters

TLDR

The large number of voltage vectors in multilevel inverters requires many calculations, hindering implementation on standard control platforms. The paper proposes a model predictive current control algorithm for multilevel converters, including a modified strategy that reduces computational load without compromising performance. The algorithm uses a discrete‑time model to predict future currents for all voltage vectors and selects the vector that minimizes a cost function, with a modified approach that cuts computation. Experimental results on five‑ and nine‑level cascaded H‑bridge inverters validate the proposed control algorithm.

Abstract

This paper presents a model predictive current control algorithm that is suitable for multilevel converters and its application to a three-phase cascaded H-bridge inverter. This control method uses a discrete-time model of the system to predict the future value of the current for all voltage vectors, and selects the vector which minimizes a cost function. Due to the large number of voltage vectors available in a multilevel inverter, a large number of calculations are needed, making difficult the implementation of this control in a standard control platform. A modified control strategy that considerably reduces the amount of calculations without affecting the system's performance is proposed. Experimental results for five- and nine-level inverters validate the proposed control algorithm.