Common-mode voltage elimination of three-level T-type inverters with a finite control set model predictive control method

The main contribution of this paper is the proposal of a new finite control set model predictive control (FCS-MPC) based method for three-level T-type inverters (3LT 2 Is) to eliminate the common-mode voltage (CMV) with considering the dead time effects. Firstly, the CMV of the 3LT 2 Is is analyzed and only six medium and one zero voltage vectors (6MV1Z) which generate zero CMV are defined as the candidate voltage vectors (VVs) for the FCS-MPC. Furthermore, the dead time effects when utilizing the defined candidate VVs with 6MV1Z are investigated and a new FCS-MPC based CMV elimination (CMV-EL) method is proposed. In the proposed CMV-EL method, the candidate voltage VVs are redefined by pre-excluding the VVs which will cause CMV fluctuations during the dead time from 6MV1Z. Besides, the proposed CMV-EL method can effectively eliminate the CMV as well as control the grid current and balance the neutral point potentials (NPPs). Finally, experimental results confirm the effectiveness of the proposed CMV-EL method.