Power converter and method for controlling same

1 . A power converter comprising:

a power converter first input end;

a power converter second input end configured to couple to a neutral line;

a power converter first output end;

a power converter second output end configured to couple to the neutral line;

an output inductor comprising:

an output inductor first end; and

an output inductor second end;

an output capacitor comprising:

an output capacitor first end coupled to the power converter first output end; and

an output capacitor second end coupled to the power converter second output end;

a first-phase bridge arm comprising a first midpoint coupled to the power converter first input end;

a first switch, wherein the power converter first input end is coupled to the first midpoint through the first switch;

a second-phase bridge arm comprising a second midpoint coupled to the output capacitor second end and the power converter second input end;

a second switch, wherein the output capacitor first end is coupled to the power converter first output end through the second switch;

a third-phase bridge arm comprising a third midpoint coupled to the output capacitor first end through the output inductor, wherein the first-phase bridge arm, the second-phase bridge arm, and the third-phase bridge arm are coupled in parallel to each other;

a current sampling circuit disposed on a connection line between the second midpoint and the output capacitor second end and configured to collect an inductive current of the output inductor; and

a controller communicatively coupled to the current sampling circuit and configured to:

control the first switch to be off and the second switch to be on before both the second-phase bridge arm and the third-phase bridge arm are in a first working state;

obtain the inductive current from the output inductor; and

obtain, based on the inductive current, an output current of the power converter.

2 . The power converter of claim 1 , wherein the current sampling circuit comprises:

an iron core;

a primary winding coupled to the iron core and comprising:

a primary winding first end coupled to the second midpoint; and

a primary winding first second end coupled to the output capacitor second end; and

a secondary winding coupled to the iron core.

3 . The power converter of claim 2 , wherein the controller is further configured to:

further obtain the inductive current when both the second-phase bridge arm and the third-phase bridge arm are in the first working state; and

further obtain, based on a capacitive current of the output capacitor, the output current.

4 . The power converter of claim 2 , further comprising a bypass branch comprising:

a bypass branch first end coupled to the power converter first input end; and

a bypass branch second end coupled to the power converter first output end,

wherein the controller is further configured to:

obtain the inductive current when the bypass branch is in a second working state; and

obtain the inductive current as the output current.

5 . The power converter of claim 1 , wherein the controller is further configured to:

further obtain the inductive current when both the second-phase bridge arm and the third-phase bridge arm are in the first working state; and

further obtain, based on a capacitive current of the output capacitor, the output current.

6 . The power converter of claim 1 , further comprising a bypass branch comprising:

a bypass branch first end coupled to the power converter first input end; and

a bypass branch second end coupled to the power converter first output end,

wherein the controller is further configured to:

obtain the inductive current when the bypass branch is in a second working state; and

determine obtain the inductive current as the output current.

7 . The power converter of claim 6 ,

wherein the controller is further configured to control the first switch and the second switch to be off before the bypass branch is in the second working state.

8 . A power converter comprising:

a power converter first input end;

a first switch coupled to the power converter first input end;

a power converter second input end configured to couple to a neutral line;

a power converter first output end;

a second switch coupled to the power converter first output end;

a power converter second output end configured to couple to the neutral line;

an output inductor comprising:

an output inductor first end; and

an output inductor second end;

an output capacitor comprising:

an output capacitor first end coupled to the power converter first output end; and

an output capacitor second end coupled to the power converter second output end;

an input capacitor comprising:

an input capacitor first end coupled to the power converter first input end; and

an input capacitor second end coupled to the power converter second input end;

an input inductor coupled to the first switch;

a first-phase bridge arm comprising a first midpoint coupled to the power converter first input end sequentially through the input inductor and the first switch;

a second-phase bridge arm comprising a second midpoint coupled to the output capacitor second end and the power converter second input end;

a third-phase bridge arm comprising a third midpoint coupled to the output capacitor first end through the output inductor, wherein the first-phase bridge arm, the second-phase bridge arm, and the third-phase bridge arm are coupled in parallel to each other;

a first current sampling circuit disposed on a first connection line between the second midpoint and the output capacitor second end and configured to collect a first inductive current of the output inductor;

a second current sampling circuit disposed on a second connection line between the power converter second input end and the second midpoint and configured to collect a second inductive current of the input inductor; and

a controller communicatively coupled to the first current sampling circuit and configured to:

obtain the first inductive current;

obtain the second inductive current; and

obtain, based on the first inductive current and the second inductive current, an output current of the power converter.

9 . The power converter of claim 8 , wherein the first current sampling circuit comprises:

an iron core;

a primary winding coupled to the iron core and comprising:

a primary winding first end coupled to the second midpoint; and

a primary winding second end coupled to the output capacitor second end; and

a secondary winding coupled to the iron core.

10 . The power converter of claim 9 , wherein the controller is further configured to:

further obtain the first inductive current when both the second-phase bridge arm and the third-phase bridge arm are in a working state; and

further obtain, based on a capacitive current of the output capacitor, the output current.

11 . The power converter of claim 9 , further comprising a bypass branch comprising:

a bypass branch first end coupled to the power converter first input end; and

a bypass branch second end coupled to the power converter first output end,

wherein the controller is further configured to:

obtain the first inductive current when the bypass branch is in a working state; and

obtain the first inductive current as the output current.

12 . The power converter of claim 8 , wherein the power converter first input end is coupled to the first midpoint through the first switch, wherein the output capacitor first end is coupled to the power converter first output end through the second switch, and wherein the controller is further configured to control the first switch to be off and the second switch to be on before both the second-phase bridge arm and the third-phase bridge arm are in a working state.

13 . A power converter comprising:

a power converter first input end;

a power converter second input end configured to couple to a neutral line;

a power converter first output end;

a power converter second output end configured to couple to the neutral line;

an output inductor comprising:

an output inductor first end; and

an output inductor second end;

an output capacitor comprising:

an output capacitor first end coupled to the power converter first output end; and

an output capacitor second end coupled to the power converter second output end;

a first-phase bridge arm comprising a first midpoint coupled to the power converter first input end;

a first switch, wherein the power converter first input end is coupled to the first midpoint through the first switch;

a second-phase bridge arm comprising a second midpoint coupled to the output capacitor second end and the power converter second input end;

a second switch, wherein the output capacitor first end is coupled to the power converter first output end through the second switch,

a third-phase bridge arm comprising a third midpoint coupled to the output capacitor first end through the output inductor, wherein the first-phase bridge arm, the second-phase bridge arm, and the third-phase bridge arm are coupled in parallel to each other;

a current sampling circuit disposed on a connection line between the second midpoint and the output capacitor second end and configured to collect an inductive current of the output inductor;

a bypass branch; and

a controller communicatively coupled to the current sampling circuit and configured to:

control the first switch and the second switch to be off before the bypass branch is in a first working state;

obtain the inductive current from the output inductor; and

obtain, based on the inductive current, an output current of the power converter.

14 . The power converter of claim 13 , wherein the current sampling circuit comprises:

an iron core;

a primary winding coupled to the iron core and comprising:

a primary winding first end coupled to the second midpoint; and

a primary winding first second end coupled to the output capacitor second end; and

a secondary winding coupled to the iron core.

15 . The power converter of claim 14 , wherein the controller is further configured to:

further obtain the inductive current when both the second-phase bridge arm and the third-phase bridge arm are in a second working state; and

further obtain, based on a capacitive current of the output capacitor, the output current.

16 . The power converter of claim 14 , wherein the bypass branch comprises:

a bypass branch first end coupled to the power converter first input end; and

a bypass branch second end coupled to the power converter first output end,

wherein the controller is further configured to:

obtain the inductive current when the bypass branch is in the first working state; and

obtain the inductive current as the output current.

17 . The power converter of claim 13 , wherein the controller is further configured to:

further obtain the inductive current when both the second-phase bridge arm and the third-phase bridge arm are in a second working state; and

further obtain, based on a capacitive current of the output capacitor, the output current.

18 . The power converter of claim 13 , wherein the controller is further configured to control the first switch to be off and the second switch to be on before both the second-phase bridge arm and the third-phase bridge arm are in a second working state.

19 . The power converter of claim 13 , wherein the controller is further configured to control the first switch to be off and the second switch to be on before both the second-phase bridge arm and the third-phase bridge arm are in a second working state:

control the first switch to be in an on state and the second switch to be in an off state;

control, after the first switch is in the on state and the second switch is in the off state, the first-phase bridge arm to be in the second working state and a bus capacitor to be in a charging state;

control, after a voltage of the bus capacitor reaches a first voltage, the first-phase bridge arm to stop working; and

control the first switch to be in an off state.

20 . The power converter of claim 13 , wherein the bypass branch further comprises:

a bypass branch first end coupled to the power converter first input end; and

a bypass branch second end coupled to the power converter first output end,

wherein the controller is further configured to:

obtain the inductive current when the bypass branch is in the first working state; and

obtain the inductive current as the output current.