Algorithm for the virtual vectors modulation in three-level inverters with a voltage-balance control loop

The modulation strategy based on virtual vectors can remove the low-frequency voltage oscillation that appears in the neutral point of the three-level inverter. However, this strategy has no natural voltage balancing. This work presents a novel space-vector modulation algorithm that includes voltage-balancing control and therefore can remove any possible imbalance. Since the algorithm takes advantage of symmetry in the space-vector diagram, it can be processed quickly in a digital-signal processor. The proposed method is verified by simulation and experiment