Common-mode voltage injection control method and apparatus for inverter

Patent metadata

Field	Value
Publication number	US-12224682-B2
Application number	US-202318154277-A
Country	US
Kind code	B2
Filing date	Jan 13, 2023
Priority date	Jul 13, 2020
Publication date	Feb 11, 2025
Grant date	Feb 11, 2025

Abstract

A common-mode voltage injection control method and apparatus for an inverter. For the method and apparatus, a common-mode voltage for a DPWM mode is calculated based on three-phase port voltages and an output power command; a common-mode voltage for an MPC modulation mode is calculated based on the direct current bus voltage, the three-phase port voltages, and the output power command; a modulation proportion is determined 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 a common-mode injection voltage is generated based on the common-mode voltage for the DPWM mode, the modulation proportion, and the common-mode voltage for the MPC modulation mode.

First claim

What is claimed is:

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.

2. The common-mode voltage injection control method according to claim 1 , further comprising:
calculating a common-mode voltage for a continuous pulse-width modulation (CPWM) mode based on the common-mode voltage for the DPWM mode and the common-mode voltage for the MPC modulation mode, wherein the common-mode voltage for the CPWM mode is between the common-mode voltage for the DPWM mode and the common-mode voltage for the MPC modulation mode; and
calculating the common-mode injection voltage based on the common-mode voltage for the DPWM mode, the modulation proportion, the common-mode voltage for the MPC modulation mode, and the common-mode voltage for the CPWM mode, wherein
the common-mode injection voltage further comprises a third part, the third part of the common-mode injection voltage is the common-mode voltage for the CPWM mode, and proportions of the third part of the common-mode injection voltage to the first part of the common-mode injection voltage and the second part of the common-mode injection voltage are determined according to the modulation proportion.

3. The common-mode voltage injection control method according to claim 2 , further comprising:
dividing a single-cycle time period of the three-phase port voltages into a first part, a second part, and a third part, wherein respective proportions of the first part of the single-cycle time period, the second part of the single-cycle time period, and the third part of the single-cycle time period in the single-cycle time period are determined according to the modulation proportion; and
respectively injecting the first part of the common-mode injection voltage, the second part of the common-mode injection voltage, and the third part of the common-mode injection voltage in the first part of the single-cycle time period, the second part of the single-cycle time period, and the third part of the single-cycle time period to generate a single cycle of the output voltage modulation wave, wherein the output voltage modulation wave is formed by cycling the single cycle of the output voltage modulation wave.

4. The common-mode voltage injection control method according to claim 3 , wherein dividing the single-cycle time period of the three-phase port voltages into the first part, the second part, and the third part further comprises:
sequentially dividing the single-cycle time period of the three-phase port voltages into six continuous and non-overlapping sectors, wherein each of the six sectors is sequentially divided into four continuous and non-overlapping sub-sectors; and
for the four sub-sectors corresponding to each of the six sectors, the common-mode voltage injection control method further comprises:
sequentially marking the four sub-sectors as a first sub-sector, a second sub-sector, a third sub-sector, and a fourth sub-sector; and
determining respective proportions of the first sub-sector, the second sub-sector, the third sub-sector, and the fourth sub-sector in the single-cycle time period according to the modulation proportion, wherein
the first sub-sector corresponds to the first part of the single-cycle time period, the third sub-sector corresponds to the second part of the single-cycle time period, and the second sub-sector and the fourth sub-sector correspond to the third part of single-cycle time period.

5. The common-mode voltage injection control method according to claim 4 , wherein duration of the second sub-sector is the same as duration of the fourth sub-sector, and the common-mode voltage injection control method further comprises:
calculating a real-time value of the common-mode voltage for the CPWM mode corresponding to the real time, based on the common-mode voltage for the DPWM mode, the common-mode voltage for the MPC modulation mode, the duration of the second sub-sector, and the real time.

6. The common-mode voltage injection control method according to claim 1 , further comprising:
dividing a time period of a plurality of consecutive cycles of the three-phase port voltages into a first segment and a second segment, wherein the first segment of the time period of the plurality of consecutive cycles and the second segment of the time period of the plurality of consecutive cycles each consist of one or more consecutive cycles in the time period of the plurality of consecutive cycles, and respective proportions of the first segment of the time period of the plurality of consecutive cycles and the second segment of the time period of the plurality of consecutive cycles in the time period of the plurality of consecutive cycles are determined according to the modulation proportion; and
respectively injecting the first part of the common-mode injection voltage and the second part of the common-mode injection voltage in the first segment of the time period of the plurality of consecutive cycles and the second segment of the time period of the plurality of consecutive cycles to generate a plurality of consecutive cycles of the output voltage modulation wave, wherein the output voltage modulation wave is formed by cycling the plurality of consecutive cycles of the output voltage modulation wave.

7. The common-mode voltage injection control method according to claim 1 , wherein the output power command comprises an active power command, and calculating the common-mode voltage for the MPC modulation mode based on the direct current bus voltage, the three-phase port voltages, and the output power command further comprises:
determining a minimum value of the three-phase port voltages and a first phase voltage corresponding to the minimum value, a maximum value of the three-phase port voltages and a second phase voltage corresponding to the maximum value, and a first phase current and a second phase current of three-phase port currents of the three-phase three-level inverter that are respectively in phase with the first phase voltage and the second phase voltage;
calculating a first feasible value of the common-mode voltage based on the active power command, the direct current bus voltage, the first phase voltage corresponding to the minimum value, and the first phase current;
calculat

Assignees

• Huawei Digital Power Tech Co Ltd

Inventors

• Yu Xinyu
• Xin Kai
• Dong Peng
• Li Junjie

Classifications

• H02J2101/24

  Photovoltaics · CPC title

• H02M7/5395

  by pulse-width modulation · CPC title

• H02M1/123

  Suppression of common mode voltage or current · CPC title

• H02M7/487

  Neutral point clamped inverters · CPC title

• H02M1/0012

  Control circuits using digital or numerical techniques (in DC/DC converters H02M3/157, H02M3/33515; in DC-AC converters H02M7/53873) · CPC title