Apparatus and method for controlling operation of linear compressor

• US 20020064463A1
• Filed: 11/21/2001
• Published: 05/30/2002
• Est. Priority Date: 11/29/2000
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Kim, Se Young, Park, Joon Hyung, Kim, Yang Kyu, Park, Jin Koo, Hwang, Yin Young
• Granted Patent: US 6,537,034 B2
• Time in Patent Office: Days
• US Class Current: 417/44.1
• CPC Class Codes: F04B 2201/0201 Position of the piston
• CPC Class Codes: F04B 2201/0206 Length of piston stroke
• CPC Class Codes: F04B 2203/0401 Current
• CPC Class Codes: F04B 2203/0402 Voltage
• CPC Class Codes: F04B 35/045 using solenoids
• CPC Class Codes: F04B 49/065 and making use of computers
• CPC Class Codes: F25B 2400/073 Linear compressors
• CPC Class Codes: F25B 49/022 Compressor control arrangements

Abstract

An apparatus for controlling an operation of a linear compressor includes: a sensorless circuit unit for detecting a current and a voltage applied to a linear compressor and outputting a work operation value corresponding to them; a stroke controller for receiving the work operation value and outputting a switching control signal corresponding to a variation amount of the work operation value; and an electric circuit unit for receiving the switching control signal from the stroke controller and outputting a certain voltage to the linear compressor, accordingly, a TDC of the piston in consideration of an error due to the nonlinear characteristic can be controlled, and thus, an operation efficiency of the linear compressor can be improved.

Claims

1. An apparatus for controlling an operation of a linear compressor comprising:

a sensorless circuit unit for detecting a current and a voltage applied to a linear compressor and outputting a work operation value corresponding to them;

a stroke controller for receiving the work operation value and outputting a switching control signal corresponding to a variation amount of the work operation value; and

an electric circuit unit for receiving the switching control signal from the stroke controller and outputting a certain voltage to the linear compressor.

2. The apparatus of claim 1, further comprises a stroke input unit for outputting a predetermined stroke command value according to a user'"'"'s input.

3. The apparatus of claim 1, wherein the stroke controller comprises:

a memory unit for sequentially storing the work operation values; and

a microcomputer for receiving a previous work operation value outputted from the memory unit and the work operation value outputted from the sensorless circuit unit, and outputting a switching control signal corresponding to a variation amount of the work operation value.

4. The apparatus of claim 1, wherein the electric circuit unit comprises a triac for receiving the switching control signal from the stroke controller, switching an AC power, and applying a stroke voltage to the linear compressor.

5. The apparatus of claim 4, wherein the stroke voltage is controlled by varying an ON/OFF period of the triac according to the switching control signal of the microcomputer.

6. The apparatus of claim 1, wherein the sensorless circuit unit comprises:

a current detector for detecting a current applied to the linear compressor; and

a work operating unit for receiving the current from the current detector, integrating it for one period, and outputting a corresponding work operation value.

7. The apparatus of claim 6, wherein the stroke controller comprises:

a memory unit for sequentially storing the work operation values; and

a microcomputer for receiving a previous work operation value outputted from the memory unit and the predetermined work operation value outputted from the work operating unit, comparing them, and outputting a corresponding switching control signal corresponding to the variation amount of the work operation value.

8. The apparatus of claim 7, wherein the microcomputer compares the current work operation value and the previous work operation value, and if the variation amount of the work operation value is less than a predetermined value, the microcomputer outputs the switching control signal while gradually varying its duty ratio, and then, if the difference between the current work operation value and the previous work operation value becomes more than the predetermined value, the microcomputer maintains and outputs the switching control signal of the current time point.

9. The apparatus of claim 7, wherein after the current work operation value and the previous work operation value are compared, the time point where a difference of the variation amount is above a predetermined value is where the TDC is ‘

0’

.

10. The apparatus of claim 1, wherein the sensorless circuit unit comprises:

a current detector for detecting a current applied to the linear compressor;

a voltage detector for detecting a voltage generated from the linear compressor;

a displacement computing unit for receiving the current detected by the current detector and the voltage detected by the voltage detector, and computing a displacement; and

a work operating unit for receiving the displacement of the displacement computing unit and the current of the current detector, operating them, and outputting a corresponding work operation value.

11. The apparatus of claim 10, wherein the work operating unit multiplies the input current and the displacement together, integrates the multiplied value, and outputs the integrated value as a work operation value (W).

12. The apparatus of claim 10, wherein the stroke controller comprises:

a memory unit for sequentially storing the work operation values; and

a microcomputer for receiving a previous work operation value outputted from the memory unit and the predetermined work operation value outputted from the work operating unit, comparing them, and outputting a corresponding switching control signal.

13. The apparatus of claim 12, wherein the microcomputer compares a current work operation signal and a previous work operation signal, and if the difference is less than a predetermined value, the microcomputer outputs the switching control signal while gradually varying its duty ratio, and then, if the difference between the current work operation signal and the previous work operation signal becomes more than the predetermined value, the microcomputer maintains and outputs the switching control signal of the current time point.

14. The apparatus of claim 13, wherein after the current work operation value and the previous work operation value are compared, the time point where a difference of the variation amount is above a predetermined value is where the TDC is ‘

0’

.

15. The apparatus of claim 1, wherein the sensorless circuit unit comprises:

a current detector for detecting a current applied to the linear compressor;

a voltage detector for detecting a voltage generated from the linear compressor;

a half-wave rectifying unit for half-wave rectifying the detected current received from the current detector, and outputting a corresponding half-wave current;

a displacement computing unit for receiving the voltage detected by the voltage detector and the half-wave current outputted from the half-wave rectifying unit, and computing a displacement; and

a work operating unit for receiving the displacement of the displacement computing unit and the half-wave current of the half-wave rectifying unit, operating them, and outputting a corresponding work operation signal.

16. The apparatus of claim 15, wherein the half-wave rectifying unit half-wave rectifies the current of the current detector and outputs a positive current or a negative current.

17. The apparatus of claim 15, wherein the work operating unit multiplies the positive current and the displacement together, integrates the multiplied value and outputs the integrated value as a work operation value.

18. The apparatus of claim 15, wherein the stroke controller comprises:

a memory unit for sequentially storing the work operation values; and

a microcomputer for receiving a previous work operation value outputted from the memory unit and the predetermined work operation value outputted from the work operating unit, comparing them, and outputting a corresponding switching control signal.

19. The apparatus of claim 18, wherein the microcomputer compares the current work operation value and the previous work operation value, and if the variation amount of the work operation value is less than a predetermined value, the microcomputer outputs the switching control signal while gradually varying its duty ratio, and then, if the difference between the current work operation value and the previous work operation value becomes more than the predetermined value, the microcomputer maintains and outputs the switching control signal of the current time point.

20. The apparatus of claim 19, wherein the time point where a variation amount of the difference between the current work operation value and the previous work operation value is above a predetermined value is where the is TDC is ‘

0’

.

21. The apparatus of claim 1, wherein the sensorless circuit unit comprises:

a current detector for detecting a current applied to the linear compressor;

a voltage detector for detecting a voltage generated from the linear compressor;

a displacement computing unit for receiving the current and the voltage and computing a displacement;

a work operating unit for receiving the displacement of the displacement computing unit and the current of the current detector, operating them, and outputting a corresponding work operation value; and

a work operation value variation amount detector for receiving the work operation value from the work operating unit, comparing it with the previous work operation value, and detecting a corresponding work operation value variation amount.

22. The apparatus of claim 21, wherein the work operating unit multiplies the input current and the displacement, integrates the multiplied value, and outputs the integrated value as a work operation value.

23. The apparatus of claim 21, wherein the work operation value variation amount detector includes a memory for sequentially storing the work operation values.

24. The apparatus of claim 21, the stroke controller comprises:

a gain computing unit for receiving the work operation value variation amount of the work operation value variation amount detector and a previous gain value, operating them, and computing a corresponding gain; and

receiving the gain from the gain computing, outputting a switching control signal with a duty ratio increased as much as the gain, and at the same time, outputting the gain to the gain computing unit.

25. The apparatus of claim 24, wherein the gain computing unit divides a previous gain by the work operation value variation amount, multiplies the divided value by a predetermined constant value, and takes the resulting value as a gain, if the work operation value variation amount inputted from the work operating unit is less than a predetermined value.

26. The apparatus of claim 25, wherein the predetermined value is ‘

2’

.

27. The apparatus of claim 24, wherein the gain computing unit outputs a work operation value variation amount inputted from the work operating unit by regarding the gain as ‘

0’

, if the work operation value variation amount inputted from the work operating unit is more than a predetermined value or less than ‘

0’

.

28. The apparatus of claim 27, wherein the predetermined value is ‘

2’

.

30. The method of claim 29, wherein the switching control signal outputting step includes a step of varying a duty ratio of the switching control signal if the variation amount of the work operation value does not correspond to the predetermined value after the detected work operation value and the stored work operation value are compared.

31. The method of claim 29, wherein the switching control signal controls the ON/OFF period of the triac by using the work operation value corresponding to the current and the voltage when the TDC is ‘

0’

.

29. A method for controlling an operation of a linear compressor comprising the steps of:

inputting a stroke command value according to a user'"'"'s input information;

detecting and outputting a current and a voltage generated when the linear compressor is driven by a stroke voltage;

detecting and outputting a work operation value by using the detected current and voltage;

receiving the work operation value, comparing it with a previous work operation value, and outputting a variation amount of the work operation value;

outputting a switching control signal if the variation amount of the work operation value satisfies a predetermined value;

switching an AC power with a triac according to the switching control signal, applying the stroke voltage to the linear compressor and driving a linear compressor.

32. A method for controlling an operation of a linear compressor comprising the steps of:

outputting a stroke command value according to a user'"'"'s input information;

detecting a current generated when the linear compressor driven according to the stroke voltage;

receiving the detected current, integrating it for one period and outputting a corresponding work operation value (Wi);

comparing the work operation value (Wi) and a previous work operation value (Wi) and outputting a variation amount of the work operation value;

outputting a switching control signal having a duty ratio of the current time point if the variation amount of the work operation value is more than a predetermined value; and

switching the AC power with the triac according to the switching control signal, applying the stroke voltage to the linear compressor and driving the linear compressor.

33. The method of claim 32, wherein the step of comparing the work operation signals includes a step of increasing a duty ratio of the switching control signal, if the difference between the current work operation value and the previous work operation value is less than the predetermined value.

34. The method of claim 32, wherein the switching control signal controls the ON/OFF period of the triac by using a work operation value corresponding to the current when the TDC is ‘

0’

.

36. The method of claim 35, wherein the work operation value comparing step includes a step of increasing the duty ratio of the switching control signal, if the variation amount of the work operation value is less than the predetermined value.

37. The method of claim 35, wherein the switching control signal controls the ON/OFF period of the triac 31 by using a work operation value corresponding to the current and the displacement when the TDC is ‘

0’

.

39. The method of claim 38, wherein the work operation value comparing step includes a step of increasing the duty ratio of the switching control signal, if the variation amount of the work operation value is less than the predetermined value.

40. The method of claim 38, wherein the switching control signal controls the ON/OFF period of the triac 43 by using a work operation value corresponding to the current and the displacement when the TDC is ‘

0’

.

41. The method of claim 38, wherein in the half-wave rectifying signal detecting step, the half-wave current may be a positive current or a negative current obtained from the detected current by using a diode.

35. A method for controlling an operation of a linear compressor comprising the steps of:

outputting a stroke command value according to user'"'"'s input information;

outputting a current and a voltage generated when the linear compressor 32 is driven by the stroke voltage;

receiving the detected current and the voltage and computing a displacement;

receiving the displacement and the detected current, multiplying the current and the displacement together, integrating the multiplied value, and outputting the integrated value as a work operation value;

receiving the work operation value (W), comparing it with a previous work operation value (W) and outputting a variation amount of the work operation value;

outputting a switching control signal having a duty ratio of the current time point if the variation amount of the work operation value is more than a predetermined value; and

switching an AC power with the triac 31 according to the switching control signal, applying a stroke voltage to the linear compressor 32, and driving the compressor.

38. A method for controlling an operation of a linear compressor comprising the steps of:

outputting a stroke command value according to user'"'"'s input information;

outputting a current and a voltage generated when a linear compressor is driven by a stroke voltage;

half-wave rectifying the detected current and outputting a corresponding half-wave current;

receiving the detected voltage and the half-wave current, computing and outputting the displacement;

receiving the displacement and the half-wave current, multiplying the half-wave current and the displacement together, integrating the multiplied value, and outputting the integrated value as a work operation value (W);

receiving the work operation value (W), comparing it with a previous work operation value (W), and outputting a variation amount of the work operation value;

outputting a switching control signal having a duty ratio of the current time point if the variation amount of the work operation value is more than a predetermined value; and

switching an AC power with a triac according to the switching control signal, and applying a stroke voltage to the linear compressor to drive the linear compressor.

42. A method for controlling an operation of a linear compressor comprising the steps of:

inputting a stroke command value according to user'"'"'s input information;

outputting a current and a voltage generated when a linear compressor 57 is driven by a stroke voltage;

receiving the detected current and voltage and computing and outputting the displacement;

receiving the displacement and the current, multiplying the current and the displacement together, integrating the multiplied value, and outputting the integrated value as a work operation value (W);

receiving the work operation value (W), comparing it with a previous work operation value (W), and outputting a corresponding variation amount of the work operation value;

receiving the work operation value variation amount and a previous gain (Gp), operating them, and computing a corresponding gain (G);

receiving the gain and outputting a switching control signal having a duty ratio increased as much as the gain; and

switching an AC power with the triac 56 according to the switching control signal, applying a stroke voltage to the linear compressor 57, and driving the compressor.

43. The method of claim 42, wherein in the gain computing step, if the work operation value variation amount is less than a predetermined value, the previous gain is divided by the work operation value variation amount and multiplies the divided value by a predetermined constant value (tuning gain), and then thusly obtained value is computed as a gain, thereby automatically controlling the gain.

44. The method of claim 42, wherein in the gain computing step, If the inputted work operation value variation amount is more than a predetermined value or less than ‘

0’

, the gain is outputted as ‘

0’

, thereby automatically controlling the gain.