Granted Patent B2

US 12,381,491 · App. 18/225,164 · Granted Aug 5, 2025

Inventors: Guiying Lin (Fujian, CN); Jinfeng Gao (Fujian, CN); Weichen He (Fujian, CN)

Assignee: CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED

H02M7/219H02M1/12H02J3/26H02M1/4216

Abstract

Claims (48)

1. A method applied to a pulse width modulation (PWM) rectifier, the method comprising:

acquiring a grid voltage and a grid current;

calculating, according to the grid voltage, a 90° lagged grid voltage by a differential tracker;

calculating instantaneous power according to the 90° lagged grid voltage and the grid current;

obtaining a first bias by obtaining a first difference between an instantaneous active power and an active power given and then inputting the first difference to a first proportional-integral controller and a first resonance controller;

calculating a power converter voltage using the first bias and according to the instantaneous power; and

obtaining, according to the power converter voltage, a corresponding pulse sequence to suppress grid voltage imbalance.

2. The method of claim 1 , wherein the acquiring the grid voltage and the grid current comprises:

acquiring a three-phase alternating current (AC) voltage and a three-phase AC current; and

performing a Clark transformation on the three-phase AC voltage and the three-phase AC current to obtain the grid voltage and the grid current in an orthogonal static coordinate system.

3. The method of claim 2 , wherein the instantaneous power comprises instantaneous active power and instantaneous reactive power.

4. The method of claim 3 , wherein the calculating the power converter voltage according to the instantaneous power comprises:

performing a Park transformation on the grid voltage in the orthogonal static coordinate system to obtain a d-axis grid voltage and a q-axis grid voltage in an orthogonal rotating coordinate system;

adding the d-axis grid voltage to the first bias to obtain a d-axis power converter voltage;

adding the q-axis grid voltage to a second bias, which is obtained by obtaining a second difference between the instantaneous reactive power and a reactive power given and then inputting the second difference to a second proportional-integral controller and a second resonance controller, to obtain a q-axis power converter voltage; and

performing an inverse Park transformation on the d-axis power converter voltage and the q-axis power converter voltage to obtain an α-axis power converter voltage and a β-axis power converter voltage.

5. The method of claim 4 , wherein the obtaining, according to the power converter voltage, the corresponding pulse sequence to suppress the grid voltage imbalance comprises:

obtaining the corresponding pulse sequence using a modulation strategy according to the α-axis power converter voltage and the β-axis power converter voltage; and

inputting the pulse sequence to a power converter to suppress the grid voltage imbalance.

6. The method of claim 5 , wherein the modulation strategy adopts pulse width modulation, space vector pulse width modulation or sinusoidal pulse width modulation.

7. An apparatus, comprising:

an acquirer to acquire a grid voltage and a grid current;

a differential tracker to calculate, according to the grid voltage, a 90° lagged grid voltage by the differential tracker;

an instantaneous power calculation structure to:

obtain a first bias by obtaining a first difference between an instantaneous active power and an active power given and then inputting the first difference to a first proportional-integral controller and a first resonance controller; and

calculate instantaneous power using the first bias and according to the 90° lagged grid voltage and the grid current;

a power converter voltage calculation structure to calculate a power converter voltage according to the instantaneous power; and

a pulse sequence acquisition structure to obtain, according to the power converter voltage, a corresponding pulse sequence to suppress grid voltage imbalance.

8. The apparatus of claim 7 , wherein

the acquirer further

acquires a three-phase alternating current (AC) voltage and a three-phase AC current; and

performs a Park transformation on the three-phase AC voltage and the three-phase AC current to obtain the grid voltage and the grid current in an orthogonal rotating coordinate system; and

the instantaneous power calculation structure further calculates the instantaneous active power and the instantaneous reactive power according to the 90° lagged grid voltage and the grid current.

9. The apparatus of claim 8 , wherein the power converter voltage calculation structure further:

performs a Park transformation on the grid voltage in an orthogonal static coordinate system to obtain a d-axis grid voltage and a q-axis grid voltage in an orthogonal rotating coordinate system;

adds the d-axis grid voltage to the first bias, to obtain a d-axis power converter voltage;

adds the q-axis grid voltage to a second bias, which is obtained by obtaining a second difference between the instantaneous reactive power and a reactive power given and then inputting the second difference to a second proportional-integral controller and a second resonance controller, to obtain a q-axis power converter voltage; and

performs an inverse Park transformation on the d-axis power converter voltage and the q-axis power converter voltage to obtain an α-axis power converter voltage and a β-axis power converter voltage.

10. The apparatus of claim 9 , wherein the pulse sequence acquisition structure further:

obtains the corresponding pulse sequence using a modulation strategy according to the α-axis power converter voltage and the β-axis power converter voltage; and

inputs the pulse sequence to a power converter to suppress the grid voltage imbalance.

11. A non-transitory computer-readable storage medium, wherein the storage medium has a computer program stored thereon, the computer program, when run by a processor, executing the method of claim 1 .

12. The method of claim 1 , further comprising:

obtaining a second bias by obtaining a second difference between an instantaneous reactive power and a reactive power given and then inputting the second difference to a second proportional-integral controller and a second resonance controller, wherein

the calculating the power converter voltage uses the first bias and the second bias.

13. The apparatus of claim 7 , wherein

the instantaneous power calculation structure further obtains a second bias by obtaining a second difference between an instantaneous reactive power and a reactive power given and then inputting the second difference to a second proportional-integral controller and a second resonance controller, and

the instantaneous power calculation structure calculates the instantaneous power using the first bias and the second bias.

Assignments (2)

Continuity (2)

References Cited (28)