Method for discharge control of full-bus load in household appliance, and related apparatuses

1 . A method for controlling a full bus load in a household electrical appliance, wherein:

the household electrical appliance comprises a three-level active Power Factor Correction (PFC) circuit, a full bus load, and a half bus load;

the three-level active PFC circuit comprises an upper half bus capacitor and a lower half bus capacitor connected in series between a positive terminal of a Direct Current (DC) bus and a negative terminal of the DC bus;

a node between the upper half bus capacitor and the lower half bus capacitor is a midpoint of the DC bus;

the full bus load is connected between the positive terminal and the negative terminal, and the half bus load is connected between the midpoint and one of the positive terminal and the negative terminal;

the three-level active PFC circuit is configured to convert an inputted three-phase power to output a first DC power through the positive terminal of the DC bus and the negative terminal of the DC bus, and to output a second DC power through the midpoint of the DC bus and the negative terminal of the DC bus or through the positive terminal of the DC bus and the midpoint of the DC bus, the first DC power being configured to supply power to the full bus load, and the second DC power being configured to supply power to the half bus load; and

the method comprises:

determining a voltage difference between the first DC power and the second DC power when the full bus load is turned off and the half bus load is turned on; and

controlling the full bus load to be turned on or off based on the voltage difference to stabilize a half bus voltage in a predetermined voltage interval.

2 . The method according to claim 1 , wherein:

when the second DC power is outputted from the midpoint of the DC bus and the negative terminal of the DC bus, the voltage difference is a voltage between the positive terminal of the DC bus and the midpoint of the DC bus; and

when the second DC power is outputted from the midpoint of the DC bus and the positive terminal of the DC bus, the voltage difference is a voltage between the midpoint of the DC bus and the negative terminal of the DC bus.

3 . The method according to claim 2 , wherein when the second DC power is outputted from the midpoint of the DC bus and the negative terminal of the DC bus, said controlling the full bus load to be turned on or off based on the voltage difference comprises:

determining a first half bus voltage reference value; and

controlling the full bus load to be turned on and adjusting the full bus load to equalize the voltage difference with the first half bus voltage reference value.

4 . The method according to claim 2 , wherein when the second DC power is outputted from the midpoint of the DC bus and the negative terminal of the DC bus, said controlling the full bus load to be turned on or off based on the voltage difference comprises:

controlling, when the voltage difference is greater than or equal to a first predetermined voltage threshold, the full bus load to be turned on to discharge the upper half bus capacitor; and

controlling, when the voltage difference is smaller than or equal to a second predetermined voltage threshold, the full bus load to be turned off to charge the upper half bus capacitor,

wherein the first predetermined voltage threshold is greater than the second predetermined voltage threshold.

5 . The method according to claim 2 , wherein when the second DC power is outputted from the midpoint of the DC bus and the positive terminal of the DC bus, said controlling the full bus load to be turned on or off based on the voltage difference comprises:

determining a second half bus voltage reference value; and

controlling the full bus load to be turned on and adjusting the full bus load to equalize the voltage difference with the second half bus voltage reference value.

6 . The method according to claim 2 , wherein when the second DC power is outputted from the midpoint of the DC bus and the positive terminal of the DC bus, said controlling the full bus load to be turned on or off based on the voltage difference comprises:

controlling, when the voltage difference is greater than or equal to a third predetermined voltage threshold, the full bus load to be turned on to discharge the lower half bus capacitor; and

controlling, when the voltage difference is smaller than or equal to a fourth predetermined voltage threshold, the full bus load to be turned off to charge the lower half bus capacitor,

wherein the third predetermined voltage threshold is greater than the fourth predetermined voltage threshold.

7 . The method according to claim 1 , wherein:

the full bus load comprises a compressor; and

the half bus load comprises a DC fan.

8 . A power control board for a household electrical appliance, comprising:

a memory; and

at least one processor;

wherein a program, for controlling a full bus load to discharge in a household electrical appliance, is stored in the memory and executable by the at least one processor, wherein the at least one processor, when executing the program for controlling the full bus load to discharge in the household electrical appliance, implements the method for controlling the full bus load to discharge in the household electrical appliance according to claim 1 .

9 . A household electrical appliance comprising:

a full bus load;

a half bus load;

a power control board comprising a three-level active Power Factor Correction (PFC) circuit and a controller,

wherein:

the three-level active PFC circuit comprises an upper half bus capacitor and a lower half bus capacitor connected in series between a positive terminal of a direct current (DC) bus and a negative terminal of the DC bus;

a node between the upper half bus capacitor and the lower half bus capacitor is a midpoint of the DC bus;

the full bus load is connected between the positive terminal and the negative terminal, and the half bus load is connected between the midpoint and one of the positive terminal and the negative terminal;

the three-level active PFC circuit is configured to convert an inputted three-phase power to output a first DC power through the positive terminal of the DC bus and the negative terminal of the DC bus, and to output a second DC power through the midpoint of the DC bus and the negative terminal of the DC bus or through the positive terminal of the DC bus and the midpoint of the DC bus, the first DC power being configured to supply power to the full bus load, and the second DC power being configured to supply power to the half bus load; and

the controller is configured to: determine a voltage difference between the first DC power and the second DC power when the full bus load is turned off and the half bus load is turned on; and control the full bus load to be turned on or off based on the voltage difference to stabilize a half bus voltage in a predetermined voltage interval.

10 . The household electrical appliance according to claim 9 , wherein:

when the second DC power is outputted from the midpoint of the DC bus and the negative terminal of the DC bus, the voltage difference is a voltage between the positive terminal of the DC bus and the midpoint of the DC bus; and

when the second DC power is outputted from the midpoint of the DC bus and the positive terminal of the DC bus, the voltage difference is a voltage between the midpoint of the DC bus and the negative terminal of the DC bus.

11 . The household electrical appliance according to claim 10 , wherein when the second DC power is outputted from the midpoint of the DC bus and the negative terminal of the DC bus, the controller is configured to control the full bus load to be turned on or off based on the voltage difference by:

determining a first half bus voltage reference value; and

controlling the full bus load to be turned on and adjusting the full bus load to equalize the voltage difference with the first half bus voltage reference value.

12 . The household electrical appliance according to claim 10 , wherein when the second DC power is outputted from the midpoint of the DC bus and the negative terminal of the DC bus, the controller is configured to control the full bus load to be turned on or off based on the voltage difference by:

controlling, when the voltage difference is greater than or equal to a first predetermined voltage threshold, the full bus load to be turned on to discharge the upper half bus capacitor; and

controlling, when the voltage difference is smaller than or equal to a second predetermined voltage threshold, the full bus load to be turned off to charge the upper half bus capacitor,

wherein the first predetermined voltage threshold is greater than the second predetermined voltage threshold.

13 . The household electrical appliance according to claim 10 , wherein when the second DC power is outputted from the midpoint of the DC bus and the positive terminal of the DC bus, the controller is configured to control the full bus load to be turned on or off based on the voltage difference by:

determining a second half bus voltage reference value; and

controlling the full bus load to be turned on and adjusting the full bus load to equalize the voltage difference with the second half bus voltage reference value.

14 . The household electrical appliance according to claim 10 , wherein when the second DC power is outputted from the midpoint of the DC bus and the positive terminal of the DC bus, the controller is configured to control the full bus load to be turned on or off based on the voltage difference by:

controlling, when the voltage difference is greater than or equal to a third predetermined voltage threshold, the full bus load to be turned on to discharge the lower half bus capacitor; and

controlling, when the voltage difference is smaller than or equal to a fourth predetermined voltage threshold, the full bus load to be turned off to charge the lower half bus capacitor,

wherein the third predetermined voltage threshold is greater than the fourth predetermined voltage threshold.

15 . The household electrical appliance according to claim 9 , wherein:

the full bus load comprises a compressor; and

the half bus load comprises a DC fan.