Linear compressor, and apparatus and method for controlling a linear compressor

Patent metadata

Field	Value
Publication number	US-10598175-B2
Application number	US-201514831923-A
Country	US
Kind code	B2
Filing date	Aug 21, 2015
Priority date	Aug 25, 2014
Publication date	Mar 24, 2020
Grant date	Mar 24, 2020

Abstract

An apparatus and a method for controlling a linear compressor, and a linear compressor operable with high power and low noise are provided. The apparatus may include a reference operating frequency determiner that determines a reference operating frequency at which a linear motor is operated, and an actual operating frequency determiner that determines an actual operating frequency as an arbitrary value included in a predetermined numerical value range in a vertical direction around the reference operating frequency. A correction signal may be determined by the actual operating frequency.

First claim

What is claimed is:

1. An apparatus for controlling a linear compressor, comprising:
a detector that detects an operating state of the linear compressor, the operating state including at least a current of a linear motor and a voltage of the linear motor;
a controller that outputs a correction signal for correcting at least an operating frequency of the linear motor based on the operating state; and
a drive signal generator that generates a drive signal of the linear motor according to the correction signal, the drive signal including a voltage and a frequency to be applied to the linear motor, and outputs the generated drive signal to the linear motor, wherein the controller includes:
a reference operating frequency determiner that determines a reference operating frequency at which the linear motor is operated according to the drive signal, the reference operating frequency being set as an operating frequency at which the operating frequency of the linear motor and a natural frequency of a piston in the linear compressor coincide with each other; and
an actual operating frequency determiner that determines an actual operating frequency within a range of actual operating frequencies centered around the reference operating frequency, wherein the correction signal is determined based on the determined actual operating frequency, and wherein the actual operating frequency is continuously changed up and down based on the range of actual operating frequencies centered around the reference operating frequency while the reference operating frequency is maintained at a same frequency, to avoid a resonance phenomenon that occurs when the actual operating frequency coincides with a mechanism natural frequency of the linear motor.

2. The apparatus according to claim 1 , wherein the detector includes:
a current detector that detects a current of the linear motor;
a voltage detector that detects a voltage of the linear motor; and
a stroke detector that detects a stroke using the detected current and the detected voltage.

3. The apparatus according to claim 2 , wherein the controller further includes:
a control signal generator that determines a current load of the linear motor according to a phase difference between the detected current and the detected stroke, and outputs to the reference operating frequency determiner a frequency control signal based on the determination result; and
a comparator that compares the actual operating frequency and a current operating frequency, and outputs a frequency correction signal based on the comparison result.

4. The apparatus according to claim 3 , wherein the control signal generator determines the current load of the linear motor according to the phase difference between the detected current and the detected stroke, and further outputs a stroke control signal based on a determination result, wherein the controller further includes a stroke determiner that determines a stroke command value for varying the stroke according to the stroke control signal, and wherein the comparator compares the stroke command value and the current stroke and outputs a stroke correction signal based on the comparison result.

5. The apparatus according to claim 1 , wherein the drive signal generator includes:
a PWM controller that performs a PWM control based on the correction signal and outputs a PWM control signal; and
an inverter that varies a voltage and a frequency to be output to the linear motor according to the PWM control signal.

6. The apparatus according to claim 1 , wherein the controller further includes a random number generator that transmits a random number to the actual operating frequency determiner, so that the actual operating frequency is determined randomly.

7. The apparatus according to claim 1 , wherein a noise signal generated in the linear compressor is transmitted to the controller, and the actual operating frequency determiner controls the actual operating frequency according to the noise signal.

8. The apparatus according to claim 7 , wherein, when the noise signal has a value smaller than a predetermined noise value, the actual operating frequency is controlled to be equal to the reference operating frequency.

9. The apparatus according to claim 7 , wherein the noise signal is transmitted to the actual operating frequency determiner.

10. The apparatus according to claim 1 , wherein, when the reference operating frequency of the linear motor does not coincide with the mechanism natural frequency of the linear compressor, the actual operating frequency determiner controls the actual operating frequency to be equal to the reference operating frequency.

11. A linear compressor operated by the apparatus of claim 1 .

12. The linear compressor according to claim 11 , wherein a noise sensor is mounted in a sealed container of the linear compressor.

13. A method for controlling a linear compressor, the method comprising:
detecting an operating state of the linear compressor;
determining a reference operating frequency to output a correction signal for correcting at least an operating frequency of a linear motor based on the operating state, the reference operating frequency being set as an operating frequency at which the operating frequency of the linear motor and a natural frequency of a piston in the linear compressor coincide with each other;
determining an actual operating frequency within a range of actual operating frequencies centered around the reference operating frequency at which the linear motor is actually operated;
comparing the actual operating frequency and a current operating frequency and determining and outputting the correction signal; and
generating a drive signal of the linear compressor according to the correction signal and outputting the generated drive signal to the linear compressor, wherein the actual operating frequency is continuously changed up and down based on the range of actual operating frequencies centered around the reference operating frequency while the reference operating frequency is maintained at a same frequency, to avoid a resonance phenomenon that occurs when the actual operating frequency coincides with a mechanism natural frequency of the linear motor.

14. The method according to claim 13 , wherein the method includes a linear change mode in which the actual operating frequency is operated to be equal to the reference operating frequency, and a random change mode in which the actual operating frequency is continuously changed.

15. The method according to claim 14 , wherein, when a current noise value of the linear compressor is greater than a predetermined noise value, the random change mode is performed.

16. The method according to claim 14 , wherein, when the linear motor is operated at a frequency in close proximity to the mechanism natural frequency causing mechanical resonance of the linear compressor, the random change mode is performed.

17. An apparatus for controlling a linear compressor, the apparatus comprising:
means for detecting an operating state of the linear compressor, the operating state including at least a current of a linear motor and a voltage of the linear motor;
means for determining a reference operating frequency to output a correction signal for correcting at least an operating frequency of a linear motor based on the operating state, the drive signal including a voltage and a frequency to be applied to the linear motor the reference operating frequency being set as an operating frequency at which the operating frequency of the linear motor and a natural frequency

Assignees

• Lg Electronics Inc

Inventors

• Kang Kyoungseok
• Yoo Jaeyoo

Classifications

• F04B35/045

  using solenoids · CPC title

• F04B39/122

  Cylinder block · CPC title

• F04B49/06 Primary

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

• F04B2203/0404

  Frequency of the electric current · CPC title

• F04B49/065

  and making use of computers · CPC title