A finite control set model predictive controller for single-phase transformerless T-type dynamic voltage restorer

This paper presents a five-level T-type multilevel inverter (MLI) with a finite control set model predictive control (FCS-MPC) scheme for a single-phase transformerless dynamic voltage restorer (DVR). Typical two-level voltage source inverters are not suitable for high-power and medium-voltage applications due to high dv/dt, large size, and high cost of the filter, as well as high voltage stress on all switches. To overcome these issues, a reduced switch count T-type MLI-based transformerless DVR is proposed. The literature does not yet describe an FCS-MPC control scheme for transformerless T-type DVR. The FCS-MPC controller predicts the future of the trajectory of the controlled variables based on a prediction model. The optimal state is then selected using a cost function that is formed by combining predicted and reference variables. The proposed control technique minimizes the total harmonic distortion to a very low value compared to a linear PI controller. In addition, this control scheme is not dependent on a modulation scheme and linear control technique. The proposed system is validated by both simulation and experimental results.