Abstract:
The existing active neutral-point-clamped three-level (ANPC-3L) inverter space vector modulation strategy point potential control effect needs to be further improved, and it is difficult to realize the organic unity of the low implementation complexity and high point potential control accuracy, particularly when the ANPC-3L inverter is operating with a high modulation ratio and low power factor. This exacerbates the issue of bus neutral-point potential fluctuation. Based on model prediction and simplified equivalent space vector modulation, a neutral-point potential control technique is presented to address the aforementioned issues. The strategy realizes fast and accurate control of the neutral-point potential by establishing a neutral-point potential prediction model and traversing to determine the optimal vector sequence and action time. The dynamic switching of the modulation mode in the uncontrollable region of the neutral-point potential reduces the neutral-point potential fluctuation of the ANPC-3L inverter by 80% in the high modulation ratio and low power factor operating condition, which equivalently reduces the demand for the capacitance value of the support capacitor. Finally, the effectiveness of the proposed control strategy is verified by a three-phase ANPC-3L inverter with a power rating of 18 kW.