Apparatus and method for controlling a linear compressor and a linear compressor and a refrigerator having the same

Patent metadata

Field	Value
Publication number	US-2016153442-A1
Application number	US-201514948600-A
Country	US
Kind code	A1
Filing date	Nov 23, 2015
Priority date	Nov 27, 2014
Publication date	Jun 2, 2016
Grant date	—

Abstract

An apparatus and method for controlling a linear compressor and a linear compressor and a refrigerator having the same are provided. The apparatus may include a drive configured to drive the linear compressor based on a control signal, a detector configured to detect a motor current of the linear compressor, an asymmetric current generator configured to generate an asymmetric motor current by applying a current offset to the detected motor current, and a controller configured to generate the control signal based on the asymmetric motor current. The current offset may be changed based on a change in a position of a piston of the linear compressor.

First claim

What is claimed is:

1 . An apparatus for controlling a linear compressor, the apparatus comprising:
a drive configured to drive the linear compressor based on a control signal; a detector configured to detect a motor current of the linear compressor; an asymmetric current generator configured to generate an asymmetric motor current by applying a current offset to the detected motor current; and a controller configured to generate the control signal based on the asymmetric motor current, wherein the current offset is changed based on a change in a position of a piston of the linear compressor.

2 . The apparatus of claim 1 , wherein the current offset is determined based on an asymmetry ratio of a stroke based on an initial value of the piston.

3 . The apparatus of claim 2 , wherein the current offset is changed such that the initial value of the piston is moved toward a top dead center when the asymmetry ratio of the stroke is greater than a predetermined asymmetry ratio, and wherein the current offset is changed such that the initial value of the piston is moved toward a bottom dead center when the asymmetry ratio of the stroke is smaller than the predetermined desired asymmetry ratio.

4 . The apparatus of claim 1 , wherein the current offset is determined based on a comparison result between the motor current and a predetermined motor current peak value.

5 . The apparatus of claim 4 , wherein the current offset is changed such that the initial value of the piston is moved toward a top dead center when the motor current is greater than the predetermined motor current peak value, and wherein the current offset is changed such that the initial value of the piston is moved toward a bottom dead center or maintained when the motor current is smaller than the predetermined motor current peak value.

6 . The apparatus of claim 5 , wherein the current offset is changed such that the initial value of the piston is moved toward a bottom dead center when the motor current is smaller than a value obtained by subtracting a predetermined current-changed amount from the predetermined motor current peak value, and when the motor current is greater than the value obtained by subtracting the predetermined current-changed amount from the predetermined motor current peak value the current offset is maintained.

7 . The apparatus of claim 1 , wherein the current offset is determined based on a comparison result between a detected stroke and a predetermined stroke peak value.

8 . The apparatus of claim 7 , wherein the current offset is changed such that the initial value of the piston is moved toward a top dead center when the detected stroke is greater than the predetermined stroke peak value, and wherein the current offset is changed such that the initial value of the piston is moved toward a bottom dead center or maintained when the detected stroke is smaller than the predetermined stroke peak value.

9 . The apparatus of claim 8 , wherein the current offset is changed, such that the initial value of the piston is moved toward a bottom dead center when the detected stroke is smaller than a value obtained by subtracting a predetermined stroke variation from the predetermined stroke peak value, and when the detected stroke is greater than the value obtained by subtracting a predetermined stroke variation from the predetermined stroke peak value the current offset is maintained.

10 . The apparatus of claim 1 , wherein the current offset is determined based on a detected top dead center.

11 . The apparatus of claim 10 , wherein the current offset is changed such that the initial value of the piston is moved toward a top dead center or a bottom dead center and thus the detected top dead center is ‘0.’

12 . The apparatus of claim 10 , wherein the controller detects a stroke based on the asymmetric motor current and a motor voltage of the linear compressor, and generates the control signal based on the detected stroke.

13 . The apparatus of claim 12 , wherein the controller detects a phase difference between a phase of the asymmetric motor current and a phase of the detected stroke, detects a top dead center of the linear compressor based on the phase difference, and generates the control signal based on the detected top dead center.

14 . The apparatus of claim 12 , wherein the controller detects a phase difference between a phase of the asymmetric motor current and a phase of the detected stroke, detects a gas spring constant based on the phase difference, the asymmetric motor current, and the detected stroke, and generates the control signal based on the gas spring constant.

15 . The apparatus of claim 14 , wherein the controller detects a top dead center of the linear compressor based on the gas spring constant, and generates the control signal based on the detected top dead center.

16 . The apparatus of claim 1 , wherein the current offset is changed according to a change in a load of the linear compressor or a cooling capacity command value applied to the linear compressor.

17 . The apparatus of claim 1 , wherein the current offset is changed according to an operation mode of the linear compressor, and wherein the operation mode is at least one of a symmetric control mode, an asymmetric control mode, or a counter-asymmetric control mode.

18 . The apparatus of claim 17 , wherein the operation mode is determined based on a load of the linear compressor or a cooling capacity command value applied to the linear compressor.

19 . The apparatus of claim 17 , wherein the controller sets the current offset to ‘0’ when the operation mode is the symmetric control mode, and sets the current offset to a value other than ‘0’ when the operation mode is the asymmetric control mode or the counter-asymmetric control mode.

20 . The apparatus of claim 19 , wherein the current offset when the operation mode is the asymmetric control mode and the current offset when the operation mode is the counter-asymmetric control mode have opposite values to each other.

21 . The apparatus of claim 19 , wherein the current offset is determined based on at least one of an asymmetry ratio of a stroke based on an initial value of the piston, a comparison result between the motor current and a predetermined motor current peak value, a comparison result between a detected stroke and a predetermined stroke peak value, or a detected top dead center.

22 . A linear compressor including the apparatus of claim 1 .

23 . A refrigerator including the linear compressor of claim 22 .

24 . A method of controlling a linear compressor, the method comprising:
detecting a motor current and a motor voltage corresponding to a motor of the linear compressor; generating an asymmetric motor current by applying a current offset to the detected motor current; generating a control signal based on the asymmetric motor current and the detected motor voltage; and driving the linear compressor based on the control signal, wherein the current offset is changed based on a change in a position of a piston of the linear compressor.

25 . A linear compressor controlled using the method of claim 24 .

26 . A refrigerator including a linear compressor controlled using the method of claim 24 .

Assignees

• Lg Electronics Inc

Inventors

• Lim Sungjin
• Park Daegeun
• Song Youngwoong

Classifications

• F04B2203/0401

  Current · CPC title

• F04B49/06 Primary

  Control using electricity (regulating by means of floats actuating electric switches F04B49/04) · CPC title

• F04B53/14

  Pistons, piston-rods or piston-rod connections · CPC title

• F04B35/04

  the means being electric · CPC title

• F04B35/045

  using solenoids · CPC title