Aimed at reducing the switching loss and common-mode voltage amplitude of\nhigh-power medium-voltage three-level inverter under low modulation index conditions, an\nimproved synchronous space vector PWM strategy is proposed in this paper. The switching times\nin each fundamental period are reduced by the re-division of small regions and the full use of the\nredundant switching state. The sum of switching algebra is introduced as an evaluation index and\nthe switching state with the minimum value of the sum of switching algebra are adopted. Then, the\ncommon mode voltage amplitude is reduced. The theoretical analysis and experimental results\nshow that the improved modulation strategy proposed in this paper can effectively reduce the\nswitching loss and common-mode voltage amplitude of the inverter under the condition of the low\nmodulation index. Moreover, the neutral-point voltage ripple is also reduced simultaneously.
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