A data-driven switching frequency control method based on finite-control-set model-predictive control (FCS-MPC) for single-phase three-level neutral-point-clamped rectifiers is proposed to achieve the accurate control of the switching frequency. Taking the switching weighting factor as input and the average switching frequency within a fixed sliding window time as output, a compact-form dynamic linearization method is used to establish an equivalent dynamic linearized data model at each dynamic operating point of the closed-loop system. Based on this data model, a data-driven controller is designed to control the switching frequency. Simulation and experimental results prove the correctness and superiority of the proposed FCS-MPC with the data-driven switching frequency control scheme.

To improve the utilization of the dc-bus voltage and solve the problem of neutral-point voltage (NP-V) unbalance and high common-mode voltage (CMV) in the overmodulation region of three-level neutral-point clamped inverters, a virtual space vector overmodulation (VSV-OVM) strategy considering NP-V balance and CMV suppression is proposed. Based on the hybrid vector correction method, the utilization of dc-bus voltage in the overmodulation region is improved, the computational burden of overmodulation algorithm is alleviated by means of fitting and establishing lookup table. Meanwhile, an effective active NP-V control method with switch states Misalignment protection is designed for the proposed VSV-OVM strategy. Furthermore, the implementation details of the proposed VSV-OVM strategy is elaborated. The experimental results verify that the proposed VSV-OVM has excellent NP-V balance and CMV suppression ability in the overmodulation region, and has higher dc-bus voltage utilization.

The three-level neutral-point clamped voltage source inverter (3L-NPC-VSI) is widely used in the maglev traction systems due to its high output voltage, large output capacity and low output current harmonics. In order to improve the utilization of the DC-bus voltage, an overmodulation strategy is necessary. This paper proposes an improved overmodulation strategy based on the minimum amplitude error method for a 3L-NPC-VSI. Compared with the conventional overmodulation strategy based on the minimum amplitude error method, the utilization of the DC-bus voltage is higher. Meanwhile, a virtual space vector modulation strategy is adopted for inverter neutral-point (NP) voltage balance and common-mode voltage (CMV) suppression. Furthermore, the suppression of leakage current also has been verified. Furthermore, the implementation details of the proposed overmodulation strategy based on minimum amplitude error method is elaborated. The effectiveness of the proposed method is verified by simulation and experimental results.

This article presents a data-driven quantitative multiobjective finite-control-set model predictive control (FCS-MPC) for three-phase three-level neutral point clamped (NPC) inverters, aiming to achieve precise control of both the switching frequency and the neutral point voltage. Considering the switching weighting factor and the neutral point voltage weighting factor as inputs, and the average switching frequency within a fixed sliding window time and the maximum value of the neutral point voltage within another fixed sliding window time as outputs, a compact form dynamic linearization (CFDL) method is employed to construct an equivalent dynamic linearized data model at each dynamic operating point of the closed-loop system. Building upon this data-driven model, a meticulously crafted controller is devised to precisely regulate both the switching frequency and the peak deviation of the neutral-point potential. The simulation and experimental results validate the correctness and demonstrate the superiority of the proposed control approach.

This paper proposes a computationally efficient sphere decoding algorithm model predictive control (SDA-MPC) method for the three-phase five-level active neutral-point clamped converter. The core of this approach is the dynamic incorporation of the neutral-point potential and the three-phase flying capacitor voltage balancing errors into the calculation of the hypersphere radius and the sphere centroid distance, which effectively achieves precise multi-capacitor voltage balancing. Furthermore, the strategy reconstructs the search tree, which contains redundant switching states, by imposing level transition constraints and sector partitioning constraints, thereby significantly reducing the maximum computational burden of the SDA-MPC. Experimental results fully validate the feasibility and superiority of the proposed method.