| CPC H02M 7/53873 (2013.01) [H02M 1/123 (2021.05); H02M 7/5395 (2013.01)] | 16 Claims |

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1. A common-mode voltage injection control method, wherein the common-mode voltage injection control method is applied to a three-phase three-level inverter, and the method comprises:
obtaining a direct current bus voltage and three-phase port voltages of the three-phase three-level inverter;
calculating a common-mode voltage for a discontinuous pulse-width modulation (DPWM) mode based on the three-phase port voltages and an output power command;
calculating a common-mode voltage for a model predictive control (MPC) modulation mode based on the direct current bus voltage, the three-phase port voltages, and the output power command;
determining a modulation proportion based on a maximum phase voltage peak value of the three-phase port voltages, the direct current bus voltage, and a power factor of the output power command; and
generating a common-mode injection voltage based on the common-mode voltage for the DPWM mode, the modulation proportion, and the common-mode voltage for the MPC modulation mode, wherein
the common-mode injection voltage is used to generate an output voltage modulation wave of the three-phase three-level inverter, the common-mode injection voltage comprises a first part and a second part, the first part of the common-mode injection voltage is the common-mode voltage for the DPWM mode, the second part of the common-mode injection voltage is the common-mode voltage for the MPC modulation mode, and a proportion of the first part of the common-mode injection voltage to the second part of the common-mode injection voltage is determined according to the modulation proportion.
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