Refrigerator having variable speed compressor and control method thereof

Patent metadata

Field	Value
Publication number	US-11454436-B2
Application number	US-201816643413-A
Country	US
Kind code	B2
Filing date	Aug 24, 2018
Priority date	Aug 28, 2017
Publication date	Sep 27, 2022
Grant date	Sep 27, 2022

Abstract

A refrigerator and a method for controlling the same are disclosed. The refrigerator may minimize the size and material cost of the control system by controlling the internal temperature and the speed of a compressor using a thermostat used in the conventional low-capacity/low-cost refrigerator without using a system controller equipped with various sensors (internal sensors and/or external sensors) capable of controlling the internal temperature. In addition, since an inverter controller capable of controlling a BLDC compressor estimates the internal/external temperature based on operation information of the compressor, and determines the internal load, it may save energy and reduce vibrations and noise, which are the largest disadvantages of a constant-speed compressor, thereby improving satisfaction of the consumer. In addition, the BLDC compressor may be started and operated stably by applying a differentiated algorithm of the inverter controller.

First claim

The invention claimed is:

1. A refrigerator comprising:
a housing forming an external appearance of the refrigerator, and including a storage chamber;
a thermostat configured to operate according to an internal temperature of the storage chamber;
a compressor comprising a motor and configured to be operated according to operation of the thermostat;
an inverter controller comprising a plurality of switching elements and configured to control an operation speed of the compressor by operating the switching elements to operate the motor, based on operation information of the compressor; and
a speed controller configured to transmit an output voltage to the inverter controller and control a duty ratio of the output voltage,
wherein the inverter controller is configured to calculate power consumption of the compressor using a voltage applied to a winding of the motor in the compressor and a current flowing in the winding of the motor, and control the operation speed of the compressor based on the calculated power consumption of the compressor,
wherein the inverter controller is configured to operate the switching elements based on the duty ratio, so that the switching elements operate at a switching frequency period corresponding to the duty ratio, and
wherein the speed controller is configured to execute a speed control at an execution period, which is the same as the switching frequency period, so that the speed control and operation of the switching elements are synchronized.

2. The refrigerator according to claim 1 , wherein the inverter controller is configured to change the operation speed of the compressor by estimating the internal temperature based on the calculated power consumption.

3. The refrigerator according to claim 2 , wherein the inverter controller is configured to compare the power consumption with a reference power, determine that the internal temperature is high when the power consumption is equal to or higher than the reference power and increase the operation speed of the compressor.

4. The refrigerator according to claim 3 , wherein the inverter controller is configured to set the reference power for different operation speeds of the compressor and change the operation speed of the compressor stepwise according to the internal temperature.

5. The refrigerator according to claim 2 , wherein the inverter controller is configured to compare the power consumption with a reference power, determine to be in a load condition where the internal temperature is appropriate when the power consumption is less than or equal to the reference power, and operate the compressor at a specified speed that is less than a maximum speed.

6. The refrigerator according to claim 1 , wherein the inverter controller is configured to change the operation speed of the compressor by estimating an external temperature based on the operation speed or an operation time of the compressor.

7. The refrigerator according to claim 6 , wherein the inverter controller is configured to compare the operation time of the compressor with a reference time, determine that the external temperature is high when the operation time is equal to or higher than the reference time and increase the operation speed of the compressor.

8. The refrigerator according to claim 6 , wherein the inverter controller is configured to compare the operation time of the compressor with reference time, determine to be in a load condition where the external temperature is appropriate when the operation time is less than or equal to the reference time, and operate the compressor at a specified speed that is less than a maximum speed.

9. The refrigerator according to claim 2 , wherein the thermostat is configured to be in a conducting state when the internal temperature increases beyond a set point as the internal temperature increases and apply power to the inverter controller.

10. The refrigerator according to claim 9 , wherein the inverter controller is configured to operate a brushless direct current (BLDC) motor in the compressor when a circuit is in a conducting state by the thermostat.

11. The refrigerator according to claim 1 , further comprising:
a filter configured to block switching noise generated in controlling the compressor.

12. A refrigerator comprising:
a brushless direct current (BLDC) compressor comprising a motor;
a thermostat configured to transmit an electrical signal according to an internal temperature of a storage chamber;
an inverter controller comprising a plurality of switching elements and configured to operate the BLDC compressor at a specified speed according to the electrical signal transmitted from the thermostat, wherein the specified speed is less than a maximum speed; and
a speed controller configured to transmit an output voltage to the inverter controller and control a duty ratio of the output voltage,
wherein the inverter controller is configured to calculate power consumption of the BLDC compressor using a voltage applied to a winding of the motor in the BLDC compressor and a current flowing in the winding of the motor during operation of the BLDC compressor at the specified speed, and control an operation speed of the BLDC compressor by estimating the internal temperature based on the calculated power consumption,
wherein the inverter controller is configured to control the operation speed by operating the switching elements to operate the motor,
wherein the inverter controller is configured to operate the switching elements based on the duty ratio, so that the switching elements operate at a switching frequency period corresponding to the duty ratio, and
wherein the speed controller is configured to execute a speed control at an execution period, which is the same as the switching frequency period, so that the speed control and operation of the switching elements are synchronized.

13. The refrigerator according to claim 12 , wherein the inverter controller is configured to control the operation speed of the BLDC compressor by estimating an external temperature using the operation speed or an operation time of the BLDC compressor.

14. The refrigerator according to claim 13 , wherein the inverter controller is configured to set a reference power for different operation speeds of the BLDC compressor and change the operation speed of the BLDC compressor stepwise according to the internal temperature.

15. A method of controlling a refrigerator including a housing having a storage chamber formed therein, a thermostat configured to operate according to an internal temperature of the storage chamber, a compressor comprising a motor and configured to be operated according to operation of the thermostat, and an inverter controller comprising a plurality of switching elements, the method comprising:
calculating power consumption of the compressor by detecting a voltage applied to a winding of the motor in the compressor and a current flowing in the winding of the motor;
comparing the calculated power consumption with reference power, and increasing an operation speed of the compressor when the power consumption is equal to or higher than the reference power;
operating the compressor at a specified speed that is less than a maximum speed when the power consumption is less than the reference power; and
performing speed control according to an output voltage, to control the switching elements to operate at a switching frequency period corresponding to a duty ratio of the output voltage so as to operate the motor, thereby changing the operation speed of the compressor,
wherein the speed control is executed at an execution period,

Assignees

• Samsung Electronics Co Ltd

Inventors

• Park Sung In
• Yoon Hyo Jin
• Park Pyeong Ki
• Shin Hyo Jae
• Yang Jae Won
• Ryu Ho-Hyun
• Je Hyung Gwan

Classifications

• F25B49/022 Primary

  Compressor control arrangements · CPC title

• F25B49/025 Primary

  Motor control arrangements · CPC title

• F25B2600/021

  Inverters therefor · CPC title

• F25B2500/19

  Calculation of parameters · CPC title

• F25B2700/2104

  of an indoor room or compartment · CPC title