Method and system for controlling vibrations in a variable displacement compressor of a refrigeration system

Abstract

The present invention discloses a method for vibration control of a variable displacement compressor of a refrigeration system, the method comprising the following steps: receiving a request to change the rotational speed of the variable displacement compressor from a current rotational speed to a reference rotational speed; verifying whether the reference rotational speed requires minimization of compressor vibration; defining a reference speed range that includes the reference speed; defining a maximum rotational speed within the rotational speed range and a minimum rotational speed within the rotational speed range; comparing a reference rotation speed with the current rotation speed; changing the rotational speed of the compressor; measuring compressor vibration within a reference speed range; specifying the minimum and maximum vibration speeds; defining a vibration difference; setting a vibration difference criterion; comparing the vibration difference with the vibration difference reference; Defining the final operating speed of the compressor.

Description

[Technical Field]

[0001] The present invention discloses a method and system for controlling vibration in a variable displacement compressor of a refrigeration system.

[0002] More specifically, the solution of the present invention aims to minimize vibration and noise in a refrigeration system with a variable displacement compressor in an active manner and using at least one vibration sensor. [Background technology]

[0003] Today, most solutions to minimize vibration and noise in refrigeration systems with variable displacement compressors are based on an a priori study of the most problematic compressor operating conditions (such conditions are primarily determined by the compressor motor speed), and then generating (prescribing) a prohibition range of operating conditions by specifying a prohibited RPM range, which becomes a permanent prohibition range for all products of the determined model.

[0004] U.S. Patent No. 5,203,178A, published April 20, 1993, entitled "Noise Control for Air Conditioners," discloses an air conditioning system having a condenser fan, an evaporator fan, a compressor, and at least two motors for driving the fans and the compressor. The air conditioning system reduces vibration by controlling the rotational speed of each motor in response to vibration in the air conditioning system. The system performs a test to determine the optimum rotational speed of the motors to minimize vibration. The system uses a microcomputer, which changes the rotational speed of at least one of the motors to each of a plurality of different speed values ​​within a predetermined speed range during the test. The system also uses at least one vibration detector, which detects vibration values ​​when the motor operates at different rotational speed values. At the end of the test, the motor is controlled to operate at the rotational speed that minimizes vibration.

[0005] U.S. Patent Application Publication US2020 / 240689A1, published June 30, 2020, and entitled "Method and Apparatus for Preventing Component Malfunctions Using an Accelerometer," discloses a method for minimizing malfunctions of components in a heating, ventilation, and air conditioning (HVAC) system, the method including measuring vibrations of at least one component of the HVAC system with an accelerometer attached to the at least one component, and receiving actual vibration data reflecting the measured vibrations by a controller. The method further includes using the controller to determine whether the actual vibration data is greater than predetermined acceptable amounts by a predetermined acceptable baseline vibration data. In response to a positive determination in the determining step, the controller adds an operational frequency of at least one component corresponding to the actual vibration data as a deadband frequency.

[0006] U.S. Patent Application Publication US2018 / 202679A1, published July 19, 2018, and entitled "Method and Apparatus for System Diagnostics Using Accelerometers," discloses a method for monitoring the health of components in a heating, ventilation, and air conditioning (HVAC) system. The method includes measuring vibrations of at least one component of the HVAC system with an accelerometer associated with the at least one component; receiving, by a controller, actual vibration data reflecting the measured vibrations; determining, using the controller, whether the actual vibration data differs from predefined acceptable baseline vibration data by more than an acceptable amount; and, in response to a positive determination in the determining step, forwarding, by the controller, information related to the determination to a monitoring device for monitoring operation of the component.

[0007] U.S. Patent Application Publication US2015 / 300684A1, published October 22, 2015, and entitled "Sound Level Control in an HVAC System," discloses a system and method for controlling sound levels in a heating, ventilation, and air conditioning (HVAC) system. The system includes a refrigeration unit including a compressor, a condenser fan, a controller, and a sound controller. The sound controller is configured to maintain the sound level of the refrigeration unit within a sound level operating range. A method for controlling a refrigeration unit for a heating, ventilation, and air conditioning (HVAC) system is described. The method includes determining, by the controller, a cooling requirement for a conditioned space. The controller also determines a sound level operating range for the refrigeration unit. The method further includes the controller applying a cooling setting based on the cooling requirement and the sound level operating range.

[0008] The specification of U.S. Patent Application Publication US2009 / 093911A1, published on April 9, 2009, and entitled "Vibration Protection in a Variable Speed ​​Compressor," discloses vibration protection in a compressor system having a variable speed compressor, the vibration protection including operating the variable speed compressor at multiple frequencies, measuring multiple vibration values ​​associated with the multiple frequencies, determining a frequency characteristic of the compressor system based on the multiple vibration values, and identifying prohibited compressor frequencies based on the frequency characteristic.

[0009] Brazilian patent document BRPI0702369A2, published on January 20, 2009, entitled "System and method for diagnosis by detection of mechanical waves in refrigeration systems and / or household appliances", discloses a system and method for diagnosis of refrigeration systems and / or household appliances, which determines and notifies the operating state of said refrigeration systems and / or their components based on a number of detected physical values.

[0010] The specification of European Patent EP3535533B1, published on September 9, 2019, for an invention entitled "Refrigeration Apparatus with Noise Sensor," discloses a refrigeration apparatus having an electric device component that generates noise during operation. A controller operates the electric device component within a normal operating power range. The noise sensor detects the intensity of the noise emitted from the electric device component. The controller is configured to change the operating power of the electric device component within the normal operating power range, determine a minimum value of the noise intensity detected by the noise sensor, and determine a noise-reduced operating power for operating the electric device component at the noise-reduced operating power.

[0011] Thus, a drawback of the prior art is the fact that by defining prohibited speed ranges for compressor operation, such prohibited ranges are permanent and do not change according to refrigeration system conditions. Summary of the Invention [Problem to be solved by the invention]

[0012] SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and system for controlling vibrations in a variable displacement compressor of a refrigeration system that overcomes the drawbacks of the prior art. [Means for solving the problem]

[0013] The above object is achieved by a method for controlling vibrations of a variable displacement compressor of a refrigeration system, the method comprising the steps of: receiving a request to change the rotational speed of the variable displacement compressor from a current rotational speed to a reference rotational speed; a step of verifying (checking, determining) whether the reference rotation speed requires minimization of compressor vibration; defining a reference speed range including the reference rotation speed; defining (specifying) a maximum rotational speed within the rotational speed range and a minimum rotational speed within the rotational speed range based on the rotational speed range and the reference rotational speed; comparing the reference rotation speed with the current rotation speed; varying the rotational speed of the compressor based on a comparison between the reference rotational speed and the current rotational speed; measuring compressor vibration within a reference speed range; defining (specifying) a minimum vibration, a minimum vibration speed, and a maximum vibration based on the vibration measured within the rotational speed range; A step of defining (determining) a vibration difference based on the lowest vibration and the highest vibration; setting a vibration difference criterion; comparing the vibration difference with the vibration difference reference; Defining (prescribing) a final operating speed for the compressor to operate based on a comparison of the vibration difference and a vibration difference criterion.

[0014] Additionally, in the method according to the invention, the reference rotational speed is, for example, a new rotational speed that the compressor is required to reach by changing from its current rotational speed.

[0015] Furthermore, in the method according to the present invention, in the step of verifying whether the reference rotation speed requires minimization of compressor vibrations, If minimization of compressor vibration is not required, the current rotation speed may be set as the reference rotation speed.

[0016] Furthermore, in the method according to the present invention, the step of defining the rotational speed range may further include: The rotational speed range is the same for all reference speeds, or The rotation speed range varies depending on the reference rotation speed.

[0017] Furthermore, in the method according to the present invention, the step of defining the minimum and maximum rotational speeds may include: The minimum rotational speed is calculated as follows: RPM_L=RPM_REF -kL.RPM_RG The maximum rotation speed is calculated as follows: RPM_H=RPM_REF +kH.RPM_RG The maximum rotation speed RPM_H and the minimum rotation speed RPM_L are defined symmetrically around (or approximately at) the reference rotation speed, and the multiplier kL is equal to the multiplier kH, or the maximum rotation speed RPM_H and the minimum rotation speed RPM_L are defined asymmetrically around (or approximately at) the reference rotation speed, and the multiplier kL is different from the multiplier kH.

[0018] Furthermore, in the method according to the present invention, during the steps of comparing the reference rotation speed with the current rotation speed and changing the rotation speed of the compressor, if the reference rotation speed is lower than the current rotation speed, the rotation speed of the compressor may be reduced at a first rate of change until it reaches the highest reference rotation speed within the rotation speed range.

[0019] Additionally, the method according to the present invention comprises a step of measuring compressor vibrations, which step may be performed as follows: The rotational speed of the compressor is gradually reduced (decelerated) in steps (step speed change) at a second rate of change from the maximum rotational speed to the minimum rotational speed. Here, the vibration is measured at each step of the speed change.

[0020] Furthermore, in the method according to the present invention, in the step of comparing the reference rotational speed with the current rotational speed and changing the reference rotational speed, when the reference rotational speed is higher than the current rotational speed, the rotational speed of the compressor may be increased at a first rate of change until it reaches a minimum rotational speed within the speed range.

[0021] Furthermore, in the method according to the invention, the step of measuring compressor vibrations may be performed as follows: The rotational speed of the compressor is gradually increased (speed-up) in steps (step speed change) at a second rate of change from the minimum rotational speed to the maximum rotational speed. Here, the vibration is measured at each step of the speed change.

[0022] Furthermore, in the method according to the present invention, in the step of defining the minimum vibration, the minimum vibration speed, and the maximum vibration, The minimum vibration is, for example, the lowest vibration level measured by at least one vibration sensor within the rotational speed range; The minimum vibration speed is, for example, the speed that makes it possible to achieve the lowest vibration within the speed range when operated by a compressor. The maximum vibration is, for example, the highest vibration level measured by at least one vibration sensor within a speed range.

[0023] Furthermore, in the method according to the present invention, in the step of determining (obtaining) the vibration difference, the vibration difference is determined by VD=VH-VL, or The vibration difference may be the percentage of the highest vibration to the lowest vibration.

[0024] Furthermore, in the method according to the invention, in the step of establishing a vibration difference criterion: The vibration difference criterion is the same for all reference rotational speeds, or The vibration difference criterion may vary for each reference rotational speed.

[0025] Additionally, in the method according to the present invention, in the step of comparing the vibration difference with a vibration difference criterion and defining a final operating speed for operating the compressor, when the vibration difference is greater than the vibration difference criterion, the final operating speed may be set as the minimum vibration speed.

[0026] Additionally, in the method according to the present invention, in the step of comparing the vibration difference with a vibration difference reference and defining a final operating speed for operating the compressor, when the vibration difference is less than the vibration difference reference, the final operating speed may be set as the reference speed.

[0027] The above object is also achieved by a system for controlling vibrations in a variable displacement compressor of a refrigeration system, the system comprising: First electronic controller; a second electronic controller; and at least one vibration sensor.

[0028] One of the advantages (effects) of the present invention is that the compressor rotation speed is defined (specified) based on a comparison (comparison result) of vibration levels within a rotation speed range, and is not dependent on the absolute value of the vibration level.

[0029] A further advantage of the present invention is that it allows the operating rotational speed of the compressor to be slightly varied to minimize vibration without compromising other characteristics of the refrigeration system that depend on the compressor rotational speed, such as cooling capacity and energy efficiency. [Brief explanation of the drawings]

[0030] The objects and advantages of the present invention will become more apparent through the following detailed description of the embodiments and non-limiting drawings presented herein.

[0031] [Figure 1] FIG. 1 shows a refrigeration system and control system according to the present invention.

[0032] [Figure 2] FIG. 2 illustrates the method according to the invention.

[0033] [Figure 3] FIG. 3 illustrates a practical use of the method and system according to the invention. [Figure 4] FIG. 4 illustrates a practical use of the method and system according to the invention.

[0034] [Figure 5] FIG. 5 shows a possible use of the method according to the invention, which is carried out on the basis of time intervals while being driven for a longer time at the same current rotation speed according to the invention. DETAILED DESCRIPTION OF THE INVENTION

[0035] The present invention discloses a system and method for vibration control of a variable displacement compressor of a refrigeration system for refrigerating an environment 5.

[0036] 1, the refrigeration system comprises an evaporator 10, a condenser 20, and a variable displacement compressor 30. In addition, there is a system for vibration control of the variable displacement compressor 30 inside the refrigeration system according to the present invention, said control system comprising a first electronic controller 40, such as an electronic thermostat, which measures the temperature of the environment to be refrigerated, a second electronic controller 50, such as a frequency inverter, which measures and defines the rotation speed of the compressor 30, and at least one vibration sensor 60, such as an accelerometer. The at least one vibration sensor 60 is connected to the second electronic controller 50, and the measured vibrations or noise are transmitted to the second controller 50.

[0037] According to FIG. 2, the start of the method according to the invention comprises a step 95 in which the second controller 50 receives a request to change the compressor rotational speed from the current rotational speed RPM_SET to a reference rotational speed RPM_REF.

[0038] If it is expected that the vibration of the compressor is minimized up to the reference rotational speed RPM_REF, the method proceeds to the next step, otherwise the current rotational speed RPM_SET is set by the second controller 50 as the reference rotational speed RPM_REF.

[0039] If it is expected that compressor vibrations are minimized for the reference rotational speed RPM_REF, the method proceeds to step 105 in which the second controller 50 defines (specifies) a rotational speed range RPM_RG having the reference rotational speed RPM_REF within the rotational speed range RPM_RG.

[0040] The rotational speed range RPM_RG may be a fixed value for any reference rotational speed RPM_REF, or may vary depending on the value of the reference rotational speed RPM_REF. For example, the rotational speed range RPM_RG may be limited to a smaller value, such as 200 RPM, when the reference rotational speed RPM_REF is a lower rotational speed, such as 2000 RPM, to minimize fluctuations in compressor cooling capacity when efficiency is a priority. On the other hand, when the reference speed RPM_REF is a higher rotational speed value, such as 4500 RPM, the rotational speed range RPM_RG may also be increased.

[0041] Then, further referring to FIG. 2, the method proceeds to step 110 in which the second controller 50 defines (specifies) a maximum rotational speed RPM_H within the rotational speed range RPM_RG and a minimum rotational speed RPM_L within the rotational speed range RPM_RG based on the rotational speed range RPM_RG and the reference rotational speed RPM_REF.

[0042] According to this definition step 110, the minimum rotation speed RPM_L is calculated as follows: RPM_L=RPM_REF - kL.RPM_RG

[0043] where RPM_REF is the reference rotation speed, kL is the multiplier, and RPM_RG is the rotation speed range.

[0044] Furthermore, the maximum rotation speed RPM_H is calculated as follows: RPM_H=RPM_REF + kH.RPM_RG

[0045] where RPM_REF is the reference rotation speed, kH is the multiplier, and RPM_RG is the reference rotation speed range.

[0046] The maximum rotational speed RPM_H and the minimum rotational speed RPM_L are defined symmetrically or asymmetrically around (or approximately around) the reference rotational speed RPM_REF. For example, if the reference rotational speed RPM_REF is 2400 RPM and the rotational speed range RPM_RG is 200 RPM, the minimum rotational speed RPM_L may be 2300 RPM, the maximum rotational speed RPM_H may be 2500 RPM, and both multipliers kL and kH may be 0.5, or the minimum rotational speed RPM_L may be 2350 RPM, the maximum rotational speed RPM_H may be 2550 RPM, the multiplier kL may be 0.25, and the multiplier kH may be 0.75, or the minimum rotational speed RPM_L may be 2400 RPM, the maximum rotational speed RPM_H may be 2600 RPM, the multiplier kL may be zero, and the multiplier kH may be 1.

[0047] Then, according to FIG. 2, the method proceeds to step 115 in which the second controller 50 compares the reference rotational speed RPM_REF with the current rotational speed RPM_SET.

[0048] Based on the comparison of the reference rotational speed RPM_REF with the current rotational speed RPM_SET (step 115), the second controller 50 determines how the rotational speed of the compressor 30 should be controlled, i.e., whether to slow down or speed up.

[0049] 2, the method therefore proceeds to step 120, in which the second controller 50 modifies the rotational speed of the compressor 30 based on the comparison (step 115) between the reference rotational speed RPM_REF and the current rotational speed RPM_SET as follows: if the reference rotational speed RPM_REF is lower than the current rotational speed RPM_SET, the rotational speed of the compressor 30 is reduced until it reaches the highest rotational speed RPM_H in the rotational speed range RPM_RG; conversely, if the reference rotational speed RPM_REF is higher than the current rotational speed RPM_SET, the rotational speed of the compressor 30 is increased until it reaches the lowest rotational speed RPM_L in the rotational speed range RPM_RG.

[0050] 2, the method continues with step 125, where compressor vibrations within the rotational speed range RPM_RG are measured by at least one vibration sensor 60 as follows: if the reference rotational speed RPM_REF is lower than the current rotational speed RPM_SET, the rotational speed of the compressor 30 is reduced to the highest reference rotational speed RPM_H at a first rate of change RPM_ROUT. The first rate of change RPM_ROUT (RPM changes / sec) is typically high to increase the rotational speed. The first rate of change RPM_ROUT is a predefined value set by the user, which depends on the application of the method. The user determines the first rate of change RPM_ROUT depending on the rotational speed at which the method must be executed. Once the maximum reference rotational speed RPM_H is reached, the rotational speed of the compressor 30 is gradually (stepwise) reduced (decelerated) from the maximum rotational speed RPM_H to the minimum rotational speed RPM_L at a second rate of change RPM_RIN. This rate of change is usually low to ensure that the vibration sensor 60 can measure vibration from RPM_H to RPM_L at each step of the stepwise speed change RPM_S. The second rate of change RPM_RIN is a predefined value set by the user, and this value depends on the application of the method. The user defines (determines) the second rate of change RPM_RIN depending on the rotational speed at which the method must be executed. Conversely, if the reference rotational speed RPM_REF is higher than the current rotational speed RPM_SET, the rotational speed of the compressor 30 is increased (accelerated) to the minimum rotational speed RPM_L at a first rate of change RPM_ROUT. When the minimum rotational speed RPM_L is reached, the speed of the compressor 30 is gradually (stepwise) increased (accelerated) from the minimum rotational speed RPM_L to the maximum rotational speed RPM_H at a second rate of change RPM_RIN, and the at least one vibration sensor 60 measures vibration at every step of the speed change RPM_S. The step-wise speed change RPM_S is a predefined value set by a user, and the user defines the step-wise speed change RPM_S according to the rotational speed at which the method must be performed.

[0051] 2, the method continues to step 130, where the second controller 50 determines, based on the vibrations measured within the rotational speed range RPM_RG (step 125), a minimum vibration VL, a minimum vibration rotational speed RPM_VL, and a maximum vibration VH. The minimum vibration VL is the lowest vibration level measured by the at least one vibration sensor 60 within the rotational speed range RPM_RG, the minimum vibration rotational speed RPM_VL is a rotational speed that, when operated by the compressor 30, enables the generation of the lowest vibration VL within the rotational speed range RPM_RG, and the maximum vibration VH is the highest vibration level measured by the at least one vibration sensor 60 within the rotational speed range RPM_RG.

[0052] 2, after the definition of step 130, the method proceeds to step 135, in which a vibration difference VD is defined by the second controller 50 based on the lowest vibration VL and the highest vibration VH. The vibration difference VD is calculated as follows: VD = VH - VL

[0053] where VH is the highest vibration in the rotational speed range RPM_RG and VL is the lowest vibration in the rotational speed range RPM_RG.

[0054] Alternatively, the vibration difference VD may be expressed as a percentage of the highest vibration VH to the lowest vibration VL as follows: VD = (VH - VL) / VL (%)

[0055] The method then proceeds to step 140 where the second controller 50 establishes (sets) a vibration difference reference VD_REF.

[0056] The vibration difference reference VD_REF is a fixed value for all reference rotational speeds RPM_REF, for example 20%, which means that the highest vibration VH is 20% higher than the lowest vibration VL. Optionally, the vibration difference reference VD_REF varies for different reference rotational speeds RPM_REF (varies depending on the reference rotational speed RPM_REF), for example, when the reference rotational speed RPM_REF is less than 2000 RPM, the vibration difference reference VD_REF is 20%, and when the reference rotational speed RPM_REF is more than 2000 RPM, the vibration difference reference VD_REF is 10%.

[0057] Then, according to FIG. 2, the method compares the vibration difference VD with a vibration difference reference VD_REF by the second controller 50 (step 145). Finally, still referring to FIG. 2, the method comprises defining, by the second controller 50, a final operating speed RPM_RSET for the compressor 30 to operate based on a comparison of the vibration difference VD with the vibration difference reference VD_REF (step 150).

[0058] In this sense, the regulation (step 150) made by the second controller 50 is performed as follows: if the vibration difference VD is greater than the vibration difference reference VD_REF, the second controller 50 sets the final operating speed RPM_RSET to be equal to the minimum vibration rotational speed RPM_VL. Conversely, if the vibration difference VD is less than the vibration difference reference VD_REF, the second controller 50 sets the value of the final operating speed RPM_RSET to be equal to the requested reference rotational speed RPM_REF.

[0059] [Example of use of the preferred embodiment of the present invention] Hereinafter, practical examples of the present invention will be described in detail.

[0060] 3 and 4, the second controller 50 receives a request to change the variable displacement compressor rotational speed from the current rotational speed RPM_SET of 3600 RPM to a lower reference rotational speed RPM_REF of 2400 RPM.

[0061] 2 and 3, if it is expected that the vibration of the compressor 30 will be minimized (become smallest) around the reference rotational speed RPM_REF, the controller defines in step 105 a rotational speed range RPM_RG of 200 RPM between 2300 RPM and 2500 RPM (multipliers kL and kH are both 0.5), and the reference rotational speed RPM_REF is within said range RPM_RG.

[0062] Continuing, according to FIG. 3, the method defines, by the second controller 50, a highest reference rotational speed RPM_H of 2500 RPM within the rotational speed range RPM_RG and a lowest reference rotational speed RPM_L of 2300 RPM within the rotational speed range RPM_RG (step 110).

[0063] 4, the method then compares the reference rotational speed RPM_REF with the current rotational speed RPM_SET (step 115) by the second controller 50. Because the reference rotational speed RPM_REF of 2400 RPM is lower than the current rotational speed of 3600 RPM, the method varies the rotational speed of the compressor 30 by decreasing the rotational speed of the compressor 30 until it reaches the highest reference rotational speed RPM_H of 2500 RPM (step 120).

[0064] 4, at least one vibration sensor 60 measures compressor vibration within the rotational speed range RPM_RG (step 125). Because the reference rotational speed RPM_REF of 2400 RPM is lower than the current rotational speed RPM_REF of 3600 RPM, the rotational speed of the compressor 30 is gradually (stepwise) decreased from 2500 RPM in 20 RPM increments RPM_S (20 RPM steps at a time) until the minimum reference rotational speed RPM_L of 2300 RPM is reached. The vibration of the compressor 30 is measured by the at least one vibration sensor 60 at each step RPM_S.

[0065] Subsequently, based on the measured vibrations (step 125), the method defines a minimum vibration VL of 0.95 mm / s, a minimum vibration rotational speed RPM_VL of 2340 RPM, and a maximum vibration of 1.90 mm / s (step 130).

[0066] Based on the definition of the minimum vibration VL and maximum vibration VH (step 130), the method defines a vibration difference VD of 0.95 mm / s (step 135). Alternatively, the vibration difference VD may be expressed as a percentage of the maximum vibration VH relative to the minimum vibration VL, which in this example is 100%.

[0067] The method includes, by the second controller 50, setting a vibration difference reference VD_REF (step 140), where the vibration difference reference VD_REF may be a fixed value for any rotational speed (all rotational speeds) or the vibration difference reference VD_REF may have different values ​​for different rotational speed ranges, in this example the vibration difference reference VD_REF is expressed as a percentage of the highest vibration VH to the lowest vibration VL.

[0068] The method compares the vibration difference VD with a vibration difference reference VD_REF by the second controller 50 (step 145).

[0069] If the vibration difference VD is greater than the vibration difference reference VD_REF, for example, if the vibration difference reference VD_REF is defined as 50%, the method determines by the second controller 50 a final operating speed RPM_RSET for the compressor 30 to operate based on a comparison of the vibration difference VD and the vibration difference reference VD_REF (step 150), where the final operating speed RPM_RSET is the minimum vibration rotational speed RPM_VL.

[0070] The comparison of the vibration difference VD with the vibration difference reference VD_REF is performed to weight how much the vibration level varies within the rotational speed range RPM_RG. Alternatively, for the example described here, the vibration difference VD may be lower than the vibration difference reference VD_REF, e.g., 20% and 40%, respectively. In such a case, the second controller 50 defines the final operating speed RPM_RSET at (the same value as) the reference rotational speed RPM_REF requested at the beginning of the method.

[0071] According to FIG. 5, the method may be executed at any time (at predetermined time intervals) to ensure that compressor vibrations are reduced not only when a reference rotational speed RPM_REF is requested, but also after a long period of operation at the same current rotational speed RPM_SET.

[0072] 5 shows the time T_VIB that is periodically checked (step 155) by the second controller 50. When the time T_VIB is reached (time T_VIB has elapsed), the method is carried out as described above, and if the comparison between the vibration difference VD and the vibration difference reference VD_REF indicates that the vibration difference VD is higher than the vibration difference reference VD_REF, the compressor rotation speed is adjusted (changed) to the minimum vibration rotation speed RPM_VL.

[0073] In addition to the above embodiments, the same inventive concepts can be applied to other alternatives or variations (possible implementations) of using the present invention, for example, a noise sensor can be used instead of a vibration sensor.

[0074] Although the present invention has been described in connection with preferred embodiments, it should be understood that it is not intended to limit the invention to such particular embodiments. 。

Claims

1. 1. A method for controlling vibrations in a variable displacement compressor (30) of a refrigeration system, comprising: receiving (95) a request to change the rotational speed of the variable displacement compressor (30) from a current rotational speed (RPM_SET) to a reference rotational speed (RPM_REF); a step (100) of verifying whether the reference rotation speed (RPM_REF) requires minimization of compressor vibrations; A step (105) of defining a reference rotational speed range (RPM_RG) including the reference rotational speed (RPM_REF); A step (110) of determining a maximum rotational speed (RPM_H) within the rotational speed range (RPM_RG) and a minimum rotational speed (RPM_L) within the rotational speed range (RPM_RG) based on the rotational speed range (RPM_RG) and the reference rotational speed (RPM_REF); comparing (115) the reference rotation speed (RPM_REF) with the current rotation speed (RPM_SET); varying (120) the rotational speed of the compressor (30) based on a comparison between the reference rotational speed (RPM_REF) and the current rotational speed (RPM_SET); measuring (125) the compressor vibration within the reference rotational speed range (RPM_RG); defining (130) a minimum vibration (VL), a minimum vibration rotational speed (RPM_VL), and a maximum vibration (VH) based on the vibrations measured within the rotational speed range (RPM_RG); determining (135) a vibration difference (VD) based on the lowest vibration (VL) and the highest vibration (VH); Setting a vibration difference reference (VD_REF) (140); comparing (145) the vibration difference (VD) with the vibration difference reference (VD_REF); defining (150) a final operating speed (RPM_RSET) for the compressor (30) to operate based on a comparison of the vibration difference (VD) and the vibration difference reference (VD_REF); A method comprising:

2. 2. The method of claim 1, wherein the reference rotational speed (RPM_REF) is a new rotational speed at which the compressor (30) is desired to operate from the current rotational speed (RPM_SET).

3. 2. The method of claim 1, wherein in the step (100) of verifying whether the reference rotational speed (RPM_REF) requires minimization of the compressor vibration, if the minimization of the compressor vibration is not required, the current rotational speed (RPM_SET) is set as the reference rotational speed (RPM_REF).

4. 2. The method according to claim 1, wherein in the step (105) of defining the rotational speed range (RPM_RG), the rotational speed range (RPM_RG) is the same for all reference rotational speeds (RPM_REF), or the rotational speed range (RPM_RG) is different for each reference rotational speed (RPM_REF).

5. In the step (110) of defining the minimum rotation speed (RPM_L) and the maximum rotation speed (RPM_H), The minimum rotation speed (RPM_L) is calculated as RPM_L = RPM_REF - kL.RPM_RG, The maximum rotation speed (RPM_H) is calculated as RPM_H = RPM_REF + kH.RPM_RG. The maximum rotational speed (RPM_H) and the minimum rotational speed (RPM_L) are defined symmetrically around or approximately around the reference rotational speed (RPM_REF), and the multiplier kL is equal to the multiplier kH, or 2. The method of claim 1, wherein the maximum rotational speed (RPM_H) and the minimum rotational speed (RPM_L) are defined asymmetrically around or approximately around the reference rotational speed (RPM_REF), and the multiplier kL is different from the multiplier kH.

6. 2. The method of claim 1, wherein, in the step of comparing (115) the reference rotational speed (RPM_REF) with the current rotational speed (RPM_SET) and the step of changing (120) the rotational speed of the compressor (30), if the reference rotational speed (RPM_REF) is lower than the current rotational speed (RPM_SET), the rotational speed of the compressor (30) is reduced at a first rate of change (RPM_ROUT) until it reaches the highest reference rotational speed (RPM_H) within the rotational speed range (RPM_RG).

7. 2. The method of claim 1, wherein in the step of measuring compressor vibration (125), the speed of the compressor (30) is gradually reduced in stepwise speed changes (RPM_S) from the highest rotational speed (RPM_H) to the lowest rotational speed (RPM_L) at a second rate of change (RPM_RIN), and the vibration is measured at each step of the stepwise speed changes (RPM_S).

8. 2. The method of claim 1, wherein, in the step of comparing (115) the reference rotational speed (RPM_REF) with the current rotational speed (RPM_SET) and the step of changing (120) the reference rotational speed (RPM_REF), if the reference rotational speed (RPM_REF) is higher than the current rotational speed (RPM_SET), the rotational speed of the compressor (30) is increased at a first rate of change (RPM_ROUT) until it reaches a minimum rotational speed (RPM_L) within the rotational speed range (RPM_RG).

9. 2. The method of claim 1, wherein in the step of measuring compressor vibration (125), the rotational speed of the compressor (30) is gradually increased in stepwise speed changes (RPM_S) from the lowest rotational speed (RPM_L) to the highest rotational speed (RPM_H) at a second rate of change (RPM_RIN), and vibration is measured at each step of the speed changes (RPM_S).

10. In the step (130) of defining the lowest vibration (VL), the lowest vibration rotational speed (RPM_VL), and the highest vibration (VH), the lowest vibration (VL) is the lowest vibration level measured by at least one vibration sensor (60) within the rotational speed range (RPM_RG); the minimum vibration rotational speed (RPM_VL) is a speed that, when operated by the compressor (30), enables the minimum vibration (VL) to be achieved within the rotational speed range (RPM_RG); 2. The method of claim 1, wherein the highest vibration (VH) is the highest vibration level measured by the at least one vibration sensor (60) within the rotational speed range (RPM_RG).

11. In the step of determining (135) the vibration difference (VD), the vibration difference (VD) is calculated as VD = VH - VL, or 2. The method according to claim 1, wherein the vibration difference (VD) is a percentage of the highest vibration (VH) to the lowest vibration (VL), and is calculated as VD = (VH - VL) / VL (unit: %).

12. 2. The method of claim 1, wherein in the step of setting (140) the vibration difference reference (VD_REF), the vibration difference reference (VD_REF) is the same for all the reference rotational speeds (RPM_REF), or the vibration difference reference (VD_REF) varies for each reference rotational speed (RPM_REF).

13. 2. The method of claim 1, wherein, in the steps of comparing (145) the vibration difference (VD) with the vibration difference reference (VD_REF) and defining (150) a final operating speed (RPM_RSET) for operation of the compressor (30), if the vibration difference (VD) is greater than the vibration difference reference (VD_REF), the final operating speed (RPM_RSET) is set to the minimum vibration rotational speed (RPM_VL).

14. 2. The method of claim 1, wherein, in the steps of comparing (145) the vibration difference (VD) with the vibration difference reference (VD_REF) and defining (150) the final operating speed (RPM_RSET) for operation of the compressor (30), if the vibration difference (VD) is less than the vibration difference reference (VD_REF), the final operating speed (RPM_RSET) is set to the reference rotational speed (RPM_REF).

15. 2. The method of claim 1, wherein the step of receiving (95) a request to change the rotational speed of the variable displacement compressor (30) from the current rotational speed (RPM_SET) to the reference rotational speed (RPM_REF) and the step of verifying (100) whether the reference rotational speed (RPM_REF) requires minimization of compressor vibrations are replaced by a step of checking (155) whether a time (T_VIB) has elapsed.

16. 1. A system for controlling vibrations in a variable displacement compressor of a refrigeration system, comprising: a first electronic controller (40); a second electronic controller (50); at least one vibration sensor (60); and A system for carrying out the method of claim 1.

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