Model Predictive Control of Three-Level Converter Considering Dead-Zone Voltage Vector

Aiming at the three-level converter, this paper proposes a finite-control-set model predictive control strategy considering dead-zone voltage vector. Based on the dead-zone effect, a virtual vector is synthesized from the basic voltage vector and the corresponding dead-zone voltage vector, and a new virtual vector control set is constructed by optimizing the dead-zone time. To reduce the amount of calculation, firstly, the reference vector is obtained by the deadbeat prediction. It is strictly proved that the Euclidean distance between the output vector and the reference vector is equivalent to the current prediction of the traditional value function. Therefore, a new simplified value function is constructed, which effectively reduces the complexity of iterative calculations. Secondly, the relevant basic vector is selected to construct a simplified control set, which significantly reduces the search space. Finally, the optimal virtual vector is selected by the value function based on the Euclidean distance, and the fast model predictive control with variable dead-zone time is realized. Compared with the traditional model predictive control, the control strategy proposed in this paper can decrease the output current pulsation and reduce the total harmonic distortion of the current by about 40%～50%, which significantly improves the control performance of the converter. © 2022 Chinese Machine Press. All rights reserved.