Power supply system, inverter, and method for controlling positive and negative bus voltages of inverter

Patent metadata

Field	Value
Publication number	US-12483158-B2
Application number	US-202318474463-A
Country	US
Kind code	B2
Filing date	Sep 26, 2023
Priority date	Mar 31, 2021
Publication date	Nov 25, 2025
Grant date	Nov 25, 2025

Abstract

A power supply system, an inverter, and a method for controlling positive and negative bus voltages of an inverter. The power supply system includes at least one group of inverters, each group of the at least one group of inverters includes a primary inverter and at least one secondary inverter corresponding to the primary inverter, an input end of the primary inverter is coupled to a direct current power supply corresponding to the primary inverter, an input end of the secondary inverter is coupled to a direct current power supply corresponding to the secondary inverter, and a three-phase output end of the primary inverter is coupled to a three-phase output end of the secondary inverter and then is connected to an alternating current power grid.

First claim

What is claimed is:

1 . A power supply system, comprising:
at least one group of inverters, each group of the at least one group of inverters comprises a primary inverter and at least one secondary inverter corresponding to the primary inverter, an input end of the primary inverter is coupled to a direct current power supply corresponding to the primary inverter, an input end of the at least one secondary inverter is coupled to a direct current power supply corresponding to the at least one secondary inverter, and a three-phase output end of the primary inverter is coupled to a three-phase output end of each of the at least one secondary inverter and then is connected to an alternating current power grid, wherein the primary inverter is configured to adjust an output common-mode direct current voltage of the primary inverter based on a first voltage difference between a positive bus voltage of the primary inverter and a negative bus voltage of the primary inverter and an output active power of the primary inverter, wherein the positive bus voltage of the primary inverter is a voltage between a positive input end of the primary inverter and a first reference voltage input end, and the negative bus voltage of the primary inverter is a voltage between the first reference voltage input end and the positive input end of the primary inverter; and the at least one secondary inverter is configured to adjust an output common-mode direct current of the at least one secondary inverter based on a second voltage difference between a positive bus voltage of the at least one secondary inverter and a negative bus voltage of the at least one secondary inverter, wherein the positive bus voltage of the at least one secondary inverter is a voltage between a positive input end of the at least one secondary inverter and a second reference voltage input end, and the negative bus voltage of the at least one secondary inverter is a voltage between the second reference voltage input end and a negative input end of the at least one secondary inverter.

2 . The power supply system according to claim 1 , wherein the primary inverter is further configured to:
when the first voltage difference is greater than a first preset voltage difference threshold, and the output active power of the primary inverter is greater than 0, increase the output common-mode direct current voltage of the primary inverter, wherein the first preset voltage difference threshold is greater than 0; or when the first voltage difference is less than a second preset voltage difference threshold, and the output active power of the primary inverter is greater than 0, reduce the output common-mode direct current voltage of the primary inverter, wherein the second preset voltage difference threshold is less than 0.

3 . The power supply system according to claim 1 , wherein the primary inverter is further configured to:
when the first voltage difference is greater than a first preset voltage difference threshold, and the output active power of the primary inverter is less than 0, reduce the output common-mode direct current voltage of the primary inverter, wherein the first preset voltage difference threshold is greater than 0; or when the first voltage difference is less than a second preset voltage difference threshold, and the output active power of the primary inverter is less than 0, increase the output common-mode direct current voltage of the primary inverter, wherein the second preset voltage difference threshold is less than 0.

4 . The power supply system according to claim 1 , wherein the primary inverter is further configured to:
adjust a direct current voltage in an initial reference output voltage to obtain a target reference output voltage, and adjust the output common-mode direct current voltage of the primary inverter based on the target reference output voltage.

5 . The power supply system according to claim 1 , wherein the at least one secondary inverter is further configured to:
when the second voltage difference is greater than a first preset voltage difference threshold, reduce the output common-mode direct current of the at least one secondary inverter, wherein the first preset voltage difference threshold is greater than 0; or when the second voltage difference is less than a second preset voltage difference threshold, increase the output common-mode direct current of the at least one secondary inverter, wherein the second preset voltage difference threshold is less than 0.

6 . The power supply system according to claim 1 , wherein the at least one secondary inverter is further configured to:
adjust a direct current voltage in an initial reference output voltage to obtain a target reference output voltage, and adjust the output common-mode direct current of the at least one secondary inverter based on the target reference output voltage.

7 . The power supply system according to claim 1 , wherein a negative input end of the primary inverter is connected to the negative input end of the at least one secondary inverter.

8 . The power supply system according to claim 1 , wherein the positive input end of the primary inverter is connected to the positive input end of the at least one secondary inverter.

9 . The power supply system according to claim 1 , wherein the at least one group of inverters comprise a first group of inverters and a second group of inverters, a negative input end of one inverter in the first group of inverters is connected to a positive input end of one inverter in the second group of inverters, the first group of inverters comprise a first primary inverter and n first secondary inverters corresponding to the first primary inverter, and the second group of inverters comprise a second primary inverter and n second secondary inverters corresponding to the second primary inverter, wherein n is a positive integer, the three-phase output end of the first primary inverter is coupled to a three-phase output end of each first secondary inverter in the n first secondary inverters and then is connected to the alternating current power grid, and a three-phase output end of the second primary inverter is coupled to a three-phase output end of each second secondary inverter in the n second secondary inverters and then is connected to the alternating current power grid.

10 . A method for controlling positive and negative bus voltages of an inverter, wherein the method is applicable to a power supply system, the power supply system comprises at least one group of inverters, each group of the at least one group of inverters comprises a primary inverter and at least one secondary inverter corresponding to the primary inverter, an input end of the primary inverter is coupled to a direct current power supply corresponding to the primary inverter, an input end of the at least one secondary inverter is coupled to a direct current power supply corresponding to the at least one secondary inverter, and a three-phase output end of the primary inverter is coupled to a three-phase output end of each of the at least one secondary inverter and then is connected to an alternating current power grid, the method comprising:
adjusting, by the primary inverter, an output common-mode direct current voltage of the primary inverter based on a first voltage difference between a positive bus voltage of the primary inverter and a negative bus voltage of the primary inverter and an output active power of the primary inverter, wherein the positive bus voltage of the primary inverter is a voltage between a positive input end of the primary inverter and a first reference voltage input end, and the negative bus voltage of the primary inverter is a voltage between the

Assignees

• Huawei Digital Power Tech Co Ltd

Inventors

• Yu Xinyu
• Xin Kai

Classifications

• H02J2101/24

  Photovoltaics · CPC title

• H02M7/493

  the static converters being arranged for operation in parallel · CPC title

• H02M1/14

  Arrangements for reducing ripples from DC input or output · CPC title

• H02J3/38

  Arrangements for feeding a single network from two or more generators or sources in parallel; Arrangements for feeding already energised networks from additional generators or sources in parallel · CPC title

• H02J3/381

  Dispersed generators · CPC title