Predictive Control of a Three-Phase Neutral-Point-Clamped Inverter

TLDR

A new predictive strategy for current control of a three‑phase neutral‑point‑clamped inverter is presented. The algorithm models the inverter, predicts each switching state, and selects the state minimizing a quality function, incorporating terms for reference tracking, dc‑link balance, and switching‑frequency reduction. Compared to an established method, the strategy delivers comparable reference tracking, lower switching frequency per semiconductor, similar transient behavior, and eliminates the need for linear controllers or modulation techniques.

Abstract

A new predictive strategy for current control of a three-phase neutral-point-clamped inverter is presented. The algorithm is based on a model of the system. From that model, the behavior of the system is predicted for each possible switching state of the inverter. The state that minimizes a given quality function is selected to be applied during the next sampling interval. Several compositions of are proposed, including terms dedicated to achieve reference tracking, balance in the dc link, and reduction of the switching frequency. In comparison to an established control method, the strategy presents a remarkable performance. The proposed method achieves comparable reference tracking with lower switching frequency per semiconductor and similar transient behavior. The main advantage of the method is that it does not require any kind of linear controller or modulation technique, achieving a different approach to control a power converter.