Dc-link capacitor voltage unbalance would affect the performance of the neutral-point clamped (NPC) three-level inverter. With the traditional virtual space vector modulation (VSVPWM) method, the dc-link capacitor voltage could be kept balance under the different modulation indexes or power factors. With the virtual medium vector being set as an adjustable one, the voltage balance could be better guaranteed no matter there might have some non-linear factors However, whether the traditional or improved VSVPWM method has a complicated trigonometric calculation, thus, a newly MPC-based virtual vector modulation has been proposed in this paper. With the 19 virtual space vectors being in roll optimisation, a nice current trajectory, dc-link capacitor voltage balance, even a relative low switch losses have been implemented. Considering that the optimised virtual space vector could not be taken as a direct output, the distribution of the basic vectors has been generated to make it being favourable for modulation. The effectiveness of this MPC-based virtual vector modulation is verified in comparisons with other methods, which can save over 67.3% execution time of the traditional SVPWM method, and over 46.6% of the improved VSVPWM way while provide a better dc-link capacitor voltage balance and output current quality.

中文翻译：

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基于新的基于MPC的虚拟矢量调制的NPC三电平逆变器的直流链路电容器电压控制

直流母线电容器电压不平衡会影响中性点钳位（NPC）三电平逆变器的性能。使用传统的虚拟空间矢量调制（VSVPWM）方法，可以在不同的调制指标或功率因数下使直流环节电容器电压保持平衡。通过将虚拟介质矢量设置为可调矢量，无论是否存在一些非线性因素，都可以更好地保证电压平衡。但是，无论是传统的还是改进的VSVPWM方法，其三角计算都非常复杂，因此，一种新的MPC-本文提出了一种基于虚拟矢量调制的方法。通过对19个虚拟空间矢量进行滚动优化，可以实现良好的电流轨迹，直流母线电容器电压平衡，甚至实现了相对较低的开关损耗。考虑到不能将优化的虚拟空间矢量作为直接输出，已经生成了基本矢量的分布以使其有利于调制。与其他方法相比，该基于MPC的虚拟矢量调制的有效性得到了验证，可以节省传统SVPWM方法超过67.3％的执行时间，并在改进的VSVPWM方法中节省超过46.6％的时间，同时提供更好的直流链路电容器电压平衡和输出电流质量。