**Improved Deadbeat FC-MPC Based on the Discrete Space Vector Modulation Method with E**ffi**cient Computation for a Grid-Connected Three-Level Inverter System**

## **Ibrahim Mohd Alsofyani and Kyo-Beum Lee \***

Department of Electrical and Computer Engineering, Ajou University, 206, World cup-ro, Yeongtong-gu, Suwon 16499, Korea

**\*** Correspondence: kyl@ajou.ac.kr; Tel.: +82-31-219-2376

Received: 5 July 2019; Accepted: 8 August 2019; Published: 13 August 2019

**Abstract:** The utilization of three-level T-type (3L T-type) inverters in finite set-model predictive control (FS-MPC) of grid-connected systems yielded good performance in terms of current ripples and total harmonic distortions. To further improve the system's performance, discrete space vector modulation (DSVM) was utilized to synthesize a higher number of virtual voltage vectors. A deadbeat control (DBC) method was used to alleviate the computational burden and provide the optimum voltage vector selection. However, 3L inverters are known to suffer from voltage deviation, owing to the imbalance of the neutral-point voltage. We have proposed a simplified control strategy for balancing the neutral point in the FS-MPC with DSVM and DBC of grid-connected systems, not requiring a weighting factor or additional cost function calculation. The effectiveness of the proposed method was validated using simulation and experiment results. Our experimental results show that the execution time of the proposed algorithm was significantly reduced, while its current quality performance was not affected.

**Keywords:** deadbeat control; discrete space vector modulation; computation efficiency; model predictive control; grid connected system; three-level system; T-type inverter
