CN-116490784-B - Linear compressor and internal crash cushion

Abstract

A linear compressor or an operating method drives a motor of the linear compressor to a reference current and detects a sampled current during driving of the motor. The linear compressor or method may further provide for calculating a variance of the current using the sampled current, determining that the calculated variance exceeds a variance threshold, and limiting the reference current based on determining that the calculated variance exceeds the variance threshold.

Inventors

• Joseph Wilson Latham
• Gregory William Hahn

Assignees

• 海尔智家股份有限公司
• 青岛海尔电冰箱有限公司
• 海尔美国电器解决方案有限公司

Dates

Publication Date

20260512

Application Date

20211118

Priority Date

20201119

Claims (17)

1. 1. A method of operating a linear compressor to correct for internal collisions between the linear compressor and a shell closing the linear compressor, the method comprising: Driving a motor of the linear compressor to a reference current; detecting a sampled current during driving of the motor; Calculating a variance of the current using the sampled current; determining that the variance of the calculated current exceeds a variance threshold, and Limiting the reference current based on determining that a variance of the calculated current exceeds the variance threshold; The method includes the steps of determining a current level of a motor, determining a current level of the motor, reducing a reference current for driving the motor in response to the one or more calculated current variances exceeding a variance threshold, which is done independent of a piston position of the motor, driving the motor using the reduced reference current after limiting the reference current, and increasing the reference current if a subsequent electrical cycle passes without the calculated current variances exceeding the variance threshold until the adjusted reference current equals a default reference current value.
2. 2. The method of claim 1, wherein the sampled current comprises a peak supply current value, and wherein the reference current comprises a reference peak current value.
3. 3. The method of claim 1, wherein the sampled current comprises a root mean square current value, and wherein the reference current comprises a reference root mean square current value.
4. 4. The method of claim 1, wherein the variance of the calculated current is a recursive variance.
5. 5. The method of claim 1, wherein calculating the variance of the current comprises: Calculating the difference between the previous sampled current and the sampled current, and A variance of a current is calculated based on the difference of a previously sampled current and the sampled current.
6. 6. The method of claim 1, wherein detecting the sampled current comprises detecting a predetermined number of sets of sampled current values, and wherein calculating the variance of the current comprises calculating the variance of the predetermined number of sets of sampled current values.
7. 7. The method of claim 6, wherein calculating the variance of the current comprises calculating an average of the predetermined number of sets of sampled current values.
8. 8. The method of claim 1, wherein determining that the variance of the calculated current exceeds the variance threshold comprises determining that a variance value of a plurality of calculated currents exceeds the variance threshold, and wherein limiting the reference current is dependent on determining that a variance value of a plurality of calculated currents exceeds the variance threshold.
9. 9. A method of operating a linear compressor to correct for internal collisions between the linear compressor and a shell closing the linear compressor, the method comprising: driving a motor of the linear compressor to a reference current during a plurality of electrical cycles; detecting a sampled current, the detecting the sampled current including detecting a discrete sampled current value for each of the plurality of electrical cycles; Calculating a variance of the current using the sampled current; determining that the variance of the calculated current exceeds a variance threshold, and Limiting the reference current based on determining that a variance of the calculated current exceeds the variance threshold independent of a piston position of the motor; The method includes the steps of determining a current level of a motor, determining a current level of the motor, reducing a reference current for driving the motor in response to the one or more calculated current variances exceeding a variance threshold, which is done independent of a piston position of the motor, driving the motor using the reduced reference current after limiting the reference current, and increasing the reference current if a subsequent electrical cycle passes without the calculated current variances exceeding the variance threshold until the adjusted reference current equals a default reference current value.
10. 10. The method of claim 9, wherein the sampled current comprises a peak supply current value, and wherein the reference current comprises a reference peak current value.
11. 11. The method of claim 9, wherein the sampled current comprises a root mean square current value, and wherein the reference current comprises a reference root mean square current value.
12. 12. The method of claim 9, wherein calculating the variance of the current is a recursive variance.
13. 13. The method of claim 9, wherein calculating the variance of the current comprises: Calculating the difference between the previous sampled current and the sampled current, and A variance of a current is calculated based on the difference of a previously sampled current and the sampled current.
14. 14. The method of claim 9, wherein the sampled current value is an absolute value of a maximum current of the corresponding electrical cycle.
15. 15. The method of claim 9, wherein detecting the sampled current comprises detecting a predetermined number of sets of sampled current values, and wherein calculating the variance of the current comprises calculating the variance of the predetermined number of sets of sampled current values.
16. 16. The method of claim 15, wherein calculating the variance of the current comprises calculating an average of the predetermined number of sets of sampled current values.
17. 17. The method of claim 9, wherein determining that the variance of the calculated current exceeds the variance threshold comprises determining that a variance value of a plurality of calculated currents exceeds the variance threshold, and wherein limiting the reference current is dependent on determining that a variance value of a plurality of calculations exceeds the variance threshold.

Description

Linear compressor and internal crash cushion Technical Field The present invention relates generally to a compressor for an electrical appliance, such as a compressor for refrigerating an electrical appliance. Background Some refrigeration appliances include a sealing system for cooling the refrigeration compartment of the refrigeration appliance. Sealing systems typically include a compressor that generates compressed refrigerant during operation of the sealing system. The compressed refrigerant flows to an evaporator where heat exchange between the refrigeration compartment and the refrigerant cools the refrigeration compartment and food items located therein. Recently, some refrigeration appliances include a linear compressor for compressing a refrigerant. Linear compressors typically include a piston and a drive coil, and they are housed within a sealed housing. The drive coil generates a force for sliding the piston forward within the chamber. During movement of the piston within the chamber, the piston compresses the refrigerant. The movement of the piston within the chamber is typically controlled such that the compressor does not strike the inner shell (i.e., as an internal collision). Such internal collisions may damage various components of the linear compressor and may be very noisy or annoying to nearby users. Even when the linear compressor is properly operated (e.g., avoiding an impact due to piston movement), it is possible that a series of internal collisions, such as a hard impact of the refrigeration door or a tilting of the linear compressor, are caused by a considerable impact. Unfortunately, as the linear compressor moves within the housing, a series of internal collisions may occur after a single collision, resulting in abrupt changes in the back emf of the motor, which makes it difficult to control the linear compressor. However, it may be difficult to predict or quickly determine when such a series of internal collisions occur. The addition of a sensor configured to detect significant movement or noise from the linear compressor may allow a wide range of collisions to occur before the system can detect and stop such collisions. Additionally or alternatively, the addition of such sensors may undesirably increase the complexity or expense of the appliance. This in turn may lead to a poor user experience, reduced reliability or unacceptably increased cost of the linear compressor. It would therefore be useful to provide a linear compressor design or method of operation for quickly detecting or mitigating internal collisions of a linear compressor with the inner surface of a surrounding casing. In particular, it would be advantageous to provide a system or method for detecting or mitigating internal collisions without the need for a separate sensor. Disclosure of Invention Various aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention. In one exemplary aspect of the present invention, a method of operating a linear compressor to correct an internal collision between the linear compressor and a shell closing the linear compressor is provided. The method may include driving a motor of the linear compressor to a reference current and detecting the sampled current during driving of the motor. The method may further include calculating a variance of the current using the sampled current, determining that the calculated variance exceeds a variance threshold, and limiting the reference current based on determining that the calculated variance exceeds the variance threshold. In another exemplary aspect of the present invention, a method of operating a linear compressor to correct an internal collision between the linear compressor and a shell closing the linear compressor is provided. The method may include driving a motor of the linear compressor to a reference current during a plurality of electrical cycles and detecting the sampled current. Detecting the sampled current may include detecting a discrete sampled current value for each of a plurality of electrical cycles. The method may further include calculating a variance of the current using the sampled current, determining that the calculated variance exceeds a variance threshold, and limiting the reference current based on determining that the calculated variance exceeds the variance threshold independent of the position of the piston of the motor. These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention. Drawings The present invention has been fully described in the specification wi