Model Predictive Control of a Four-Level T-NNPC Inverter without Weighting Factors

The finite control set model predictive control (FCS-MPC) has obtained a lot of attention for power converters due to its advantages of high performance and multi-objective capability. In conventional MPC formulation, the multi-objective capability is achieved through designing a cost function with delicate weighting factors. The choice of the weighing factors influences the system performance or even stability in some cases. To avoid this problem, this paper proposes a finite control set model predictive control (FCS-MPC) scheme that achieves multi-objectives without introducing any weighting factors. The proposed MPC scheme is validated on a four-level T-NNPC inverter where the multi-objective such as current tracking, floating capacitor balancing, and common-mode voltage (CMV) reduction are all desired. Compared with the conventional cost-function-based MPC scheme, the MPC controller design procedures is simplified without sacrificing the overall performance. The simulations validate the performance of the proposed MPC scheme.