An Improved Model Predictive Control with Neutral-Point Voltage Balancing and Common-Mode Voltage Suppression for Three-Level T-type Converters

The three-phase three-level T-type converters have been used in many industrial applications. However, the common-mode voltage (CMV) and neutral point (NP) voltage are a coupled issue. In this paper, an improved model predictive control (MPC) method is proposed to solve this problem. Firstly, the CMV is analyzed and vectors with smaller CMV are selected as the candidate vectors. Secondly, the space voltage vector diagram is divided into 12 sectors and in each sector two seven-segment sequences are adopted. By switching them, the NP voltage can be balanced actively and no addition switching occurs. Thirdly, the duty ratios are calculated through the cost function results. Finally, the steady-state and the dynamic simulations are conducted to verify the effectiveness of the proposed MPC method.