US20140212266A1

US20140212266A1 - Device and method for reducing vibration in a compressor

Info

Publication number: US20140212266A1
Application number: US14/162,068
Authority: US
Inventors: Juhyoung LEE; Jinhee Noh
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2013-01-29
Filing date: 2014-01-23
Publication date: 2014-07-31
Also published as: CN103967764B; ES2570981T3; EP2759788A1; EP2759788B1; CN103967764A; KR20140096871A; KR102037290B1

Abstract

A device and method for reducing vibration in a compressor are provided. The device for reducing vibration in a compressor may include a compressor controlled to be operated at a target operating velocity after starting; a power supply that supplies power to the compressor; and a controller that controls the power supply so that a magnitude or a phase of the power supplied to the compressor is changed. The controller may control the power supply so that vibration generated in the compressor is offset by an exciting force generated in the compressor within a predetermined time interval multiple times when the compressor starts or when the compressor stops during a target operation velocity operating of the compressor.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application claims priority under 35 U.S.C. 119 and 35 U.S.C. 365 to Korean Patent Application No. 10-2013-0010013, filed in Korea on Jan. 29, 2013, which is hereby incorporated by reference in its entirety.

BACKGROUND

1. Field
A device and method for reducing vibration in a compressor are disclosed herein.
2. Background
A refrigeration cycle is a series of cycles of compression, condensation, expansion, and evaporation, and is used in an air conditioner. The air conditioner may perform heating using condensation heat of refrigerant and perform cooling using evaporation heat.
A device that compresses the refrigerant in the refrigeration cycle is a compressor. The compressor is connected with a condenser or an evaporator by a pipe through which the refrigerant flows in the refrigeration cycle.
As the compressor, a constant-velocity compressor and an inverter compressor are primarily used, and a velocity control pattern for the constant-velocity compressor and inverter compressor is illustrated in FIG. 1 according to the related art. FIG. 1A is a graph illustrating an operating velocity of the compressor with time when operating the constant-velocity compressor, and FIG. 1B is a graph illustrating an operating velocity of the compressor with time when operating the inverter compressor.
Referring to FIG. 1A, the constant-velocity compressor is abruptly accelerated up to the operating velocity in starting and abruptly stopped in stopping. Referring to FIG. 1B, the inverter compressor is accelerated up to the operating velocity relatively slowly as compared with the constant-velocity compressor, but abruptly stopped in stopping like the constant-velocity compressor.
FIG. 2A illustrates a velocity control pattern for a constant-velocity compressor according to the related art. FIG. 2B illustrates an exciting force generated in a compressor by the velocity control pattern of FIG. 2A. FIG. 2C illustrates vibration generated in a compressor by the velocity control pattern of FIG. 2A. FIG. 2D illustrates stress that acts on a pipe connected with a compressor due to the velocity control pattern of FIG. 2A.
Referring to FIGS. 2A-2D, the exciting force acts on the compressor when the compressor starts and stops, and as a result, the compressor vibrates and stress having the same pattern as the vibration of the compressor acts on the pipe connected with the compressor. Therefore, when the compressor is operated according to the velocity control pattern according to the related art, the stress acts on the pipe connected with the compressor whenever the compressor starts or stops, and as a result, the pipe may be broken.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will be described in detail with reference to the following drawings in which like reference numerals refer to like elements, and wherein:

FIGS. 1A-1B are graphs illustrating an operating velocity pattern of a compressor according to the related art, FIG. 1A illustrating the operating velocity pattern in the case of a constant-velocity compressor, and FIG. 1B illustrating the operating velocity pattern in the case of an inverter compressor;

FIG. 2A illustrates a velocity control pattern for a constant-speed compressor according to the the related art;

FIG. 2B illustrates an exciting force generated in a compressor by the velocity control pattern of FIG. 2A;

FIG. 2C illustrates vibration generated in a compressor by the velocity control pattern of FIG. 2A;

FIG. 2D illustrates stress that acts on a pipe connected with a compressor due to the velocity control pattern of FIG. 2A;

FIG. 3 is a schematic diagram of a device for reducing vibration in a compressor according to an embodiment;

FIG. 4A illustrates a velocity control pattern for a device for reducing vibration in a compressor according to an embodiment;

FIG. 4B illustrates an exciting force generated in the compressor by the velocity control pattern of FIG. 4A;

FIG. 4C illustrates vibration generated in a compressor by the velocity control pattern of FIG. 4A;

FIG. 4D illustrates stress that acts on a pipe connected with a compressor due to the velocity control pattern of FIG. 4A.

FIG. 5A illustrates a velocity control pattern by the device for reducing vibration in a compressor according to an embodiment;

FIG. 5B is a graph illustrating a magnitude of current provided to the compressor for the velocity control pattern of FIG. 5A;

FIG. 6 is a flowchart illustrating a method for reducing vibration in a compressor according to an embodiment;

FIG. 7A is a graph illustrating an acceleration pattern when a compressor velocity is accelerated in two stages;

FIG. 7B is a graph illustrating an acceleration pattern when a compressor velocity is accelerated in three stages;

FIG. 7C is a graph illustrating an acceleration pattern when a compressor velocity is accelerated in four stages;

FIG. 8A illustrates an acceleration pattern of a method for reducing vibration in a compressor according to another embodiment; and

FIG. 8B is a graph illustrating a result of Equation 2 discussed herein below.

DETAILED DESCRIPTION

Hereinafter, a device and method for reducing vibration in a compressor according an embodiments will be described in detail with reference to the accompanying drawings. Where possible, like refernce numerals have been used to indicate like elements, and repetitive disclosure has been omitted.
FIG. 3 is a schematic diagram of a device for reducing vibration in a compressor according to an embodiment. Further, FIG. 4A illustrates a velocity control pattern for a device for reducing vibration in a compressor according to an embodiment.
Referring to FIG. 3, the device for reducing vibration in a compressor according to this embodiment may include a compressor 100, a power supply 200, and a controller 300. The compressor 100 may be connected with a pipe 10. For example, the compressor 100 may form a refrigeration cycle together with a condenser 20, an evaporator 30, and an expansion device 40 and serve to compress and discharge refrigerant. For example, the compressor 100 may be connected with the condenser 20 and the evaporator 30 through the pipe 10.
The compressor 100 may be operated at a target operating velocity Vp until a stop signal is input after starting.
The power supply 200 may serve to supply power to the compressor 100. The power supply 200 may supply power by changing a magnitude and a phase of power provided to the compressor 100 according to a control by the controller 300 as described hereinbelow.
The controller 300 may control the power supply 200 to damp vibration, which may be generated in the compressor 100, by an exciting force when the exciting force is generated temporally separately multiple times, that is, with a difference of a set time at a time when the compressor 100 starts or stops. That is, the controller 300 may control the power supply 200 so that vibration generated in the compressor in starting or stopping is minimized.
Herein, the exciting force generated multiple times may include a first exciting force (see A in FIGS. 4A-4D) generated in starting, that is, when a starting signal is input into the compressor 100, and a second exciting force (see B in FIGS. 4A-4D) generated just after the first exciting force A. The first exciting force A and the second exciting force B may be generated with a temporal separation which is approximately ½ of a natural frequency of the vibration of the compressor 100, for example, as illustrated in FIGS. 4A-4D, that is, approximately half of a period of the natural frequency of the vibration.
The first exciting force A may be an exciting force generated by a current applied to the compressor 100, so that the compressor 100 is operated at a velocity (first velocity, V1), which is half of the target operating velocity Vp, as discussed hereinbelow. In addition, the second exciting force B may be an exciting force generated by a current applied to the compressor 100, so that the compressor 100 currently operated at the velocity (first velocity, V1), which is half of the target operating velocity, is operated at the target operating velocity Vp. A magnitude of the first exciting force A may be relatively larger than a magnitude of the second exciting force B.
As a result, a first vibration C generated in the compressor 100 by the first exciting force A may include a first wave a, a second wave b, and a third wave c, as illustrated in FIGS. 4A-4D. In addition, a second vibration D generated in the compressor 100 by the second exciting force B may include a first wave a′ and a second wave b′, as illustrated in FIGS. 4A-4D. The second wave b of the first vibration C may be equal to the first wave a′ of the second vibration D in magnitude and opposite in direction, and as a result, both exciting forces may be offset. Similarly, the third wave c of the first vibration C may be equal to the second wave b′ of the second vibration in magnitude and opposite in direction, and as a result, both exciting forces may be offset.
However, the first wave a of the first vibration C generated in a first interval I, which is an interval before the second exciting force B is generated after the first exciting force A is generated, may not be offset but may remain. Therefore, stress equivalent to the vibration generated in the compressor 100 may be generated in the pipe 10 connected with the compressor 100 in the first interval I. However, all vibration of the compressor 100 may be offset, and thus, not generated after the first interval I, and as a result, the stress does not act on the pipe 10. Therefore, the total stress S that acts on the pipe 10 when the compressor 100 starts becomes the stress generated in the first interval I, as illustrated in FIGS. 4A-4D.
After the first interval I, the compressor 100 may be operated at the target operating velocity Vp until a stopping signal of the compressor is recognized.
Further, the aforementioned generation of the exciting force multiple times may include a third exciting force (see A′ in FIGS. 4A-4D) generated in stopping, that is, when the stopping signal is input into the compressor 100, and a fourth exciting force (see B′ in FIGS. 4A-4D) generated just after the third exciting force A′. The third exciting force A′ and the fourth exciting force B′ may be generated with a temporal separation, which may be approximately ½ of the natural frequency of the vibration of the compressor 100, for example, as illustrated in FIGS. 4A-4D, that is, approximately half of a period of the natural frequency of the vibration.
The third exciting force A′ may be an exciting force generated by a current applied to the compressor 100, so that the compressor 100 is operated at the velocity (first velocity, V1), which is half of the target operating velocity of the compressor 100. In addition, the fourth exciting force B′ may be an exciting force generated by a current applied to the compressor 100, so that the compressor 100 completely stops at the velocity (first velocity, V1), which is half of the target operating velocity of the compressor 100. A magnitude of the third exciting force A′ may be relatively larger than a magnitude of the fourth exciting force B′.
As a result, a third vibration C′ may be generated in the compressor 100 by the third exciting force A′, and a fourth vibration D′ may be generated in the compressor 100 by the fourth exciting force B′. As the aforementioned description of the first vibration C and the second vibration D may be applied to the third vibration C′ and the fourth vibration D′, repetitive description thereof has been omitted.
Similarly to the first interval I, as a second interval II, which is an interval before the fourth vibration D′, is generated, the third vibration C′ may not be offset but may remain. Therefore, stress equivalent to the vibration generated in the compressor 100 may be generated in the pipe 10 connected with the compressor 100 in the second interval II. However, all vibrations of the compressor 100 may be offset, and thus, not generated after the second interval II, and as a result, the stress may not act on the pipe 10. Therefore, a total stress S that acts on the pipe 10 when the compressor 100 stops becomes the stress generated in the second interval II, as illustrated in FIGS. 4A-4D.
Therefore, the stress that acts on the compressor 100 and the pipe 10 connected to the compressor 100 may be minimized by the device for reducing vibration in the compressor according to embodiments. Further, the first exciting force A and the third exciting force A′, and the second exciting force B and the fourth exciting force B′ described above may be provided by supplying a current pattern as illustrated in FIG. 5 to the compressor 100.
For example, the first exciting force A and the third exciting force A′, and the second exciting force B and the fourth exciting force B′ may be generated by an impulse current as illustrated in FIGS. 5A-5B; however, embodiments are not limited thereto. Further, the controller 300 may primarily accelerate the compressor up to the first velocity V1, which may be less than the target operating velocity Vp, at the time of starting the compressor 100, and thereafter, secondarily accelerate the compressor up to the target operating velocity Vp after time has elapsed. A time when the secondary acceleration starts may be a time after approximately ½ of the natural frequency of the vibration of the compressor 100 has elapsed from the time when the primary acceleration starts. In addition, the first velocity V1 may be approximately half of the target operating velocity Vp, and in this case, the vibration generated in the compressor may be minimized as described above.
Further, the controller 300 may primarily decelerate the compressor 100 down to the first velocity (see V1 in FIGS. 4A-4D), which is less than the operating velocity (see Vp in FIGS. 4A-4D, as the compressor 100 is operated at the target operating velocity, the operating velocity and the target operating velocity are equal to each other) when the compressor 100 stops, and thereafter, secondarily decelerates the compressor 100 so that the compressor 100 completely stops after the time has elapsed. A time when the secondary deceleration starts may be a time after approximately ½ of the natural frequency of the vibration of the compressor 100 has elapsed from the time when the primary deceleration starts. In addition, the first velocity V1 may be approximately half of the operating velocity Vp, and in this case, the vibration generated in the compressor 100 may be minimized as described above.
Hereinafter, a method for reducing vibration in a compressor according an embodiment will be described in detail with reference to the accompanying drawings.
FIG. 6 is a flowchart illustrating a method for reducing vibration in a compressor according to an embodiment. Hereinafter, the method for reducing vibration in a compressor according to embodiments is described on the presumption that an initial state of the compressor 100 is a stop state, but this is for ease of description and embodiments are not limited thereto.
Referring to FIG. 6, first, a compressor, such as compresssor 100 of FIG. 3, which is in the stop state, may be primarily accelerated up to a first velocity (S100). The first velocity may be a velocity corresponding to approximately half of a target operating velocity to be described below; however, embodiments are not limited thereto.
In addition, after a time as long as approximately ½ of a natural frequency of the vibration of the compressor from a time when the primary acceleration starts, the compressor may be secondarily accelerated up to the target operating velocity. The primary acceleration and the second acceleration may be achieved by supplying an impulse current corresponding to a maximum current to the compressor, for example. Thereafter, the compressor may be operated while constantly maintaining the target operating velocity (S300).
Thereafter, the compressor may be primarily decelerated down to a second velocity (S400). The second velocity may be a velocity corresponding to approximately half of a target operating velocity similarly as the first velocity; however, embodiments are not limited thereto.
In addition, after a time as long as approximately ½ of a natural frequency of the vibration of the compressor from a time when the primary deceleration starts, the compressor may be secondarily decelerated so that the compressor completely stops (S500). The primary deceleration and the secondary deceleration may be achieved by supplying an impulse current corresponding to a minimum current.
A series of steps from the start to the stoppage of the compressor may be completed through steps S100 to S500.
Hereinafter, a method for reducing vibration in a compressor according another embodiment will be described in detail with reference to the accompanying drawings.
FIGS. 7A-7C illustrate an acceleration pattern to be used in a method for controlling vibration in a compressor according to another embodiment. That is, FIG. 7A is a graph illustrating an acceleration pattern when a compressor velocity is accelerated in two stages, FIG. 7B is a graph illustrating an acceleration pattern when a compressor velocity is accelerated in three stages. FIG. 7C is a graph illustrating an acceleration pattern when a compressor velocity is accelerated in four stages. Further, FIG. 8 is a graph illustrating a result of Equation 2 discussed hereinbelow.
Hereinafter, accelerating the velocity of the compressor will be described as an example for easy description, but the following contents may be applied to even decelerating the compressor.
In a case where the velocity of the compressor 100 is accelerated, when the velocity is accelerated as an impulse pattern in two stages, as illustrated in FIG. 7A, the velocity is accelerated as an impulse pattern in three stages, as illustrated in FIG. 7B, or the velocity is accelerated as an impulse pattern in four stages, as illustrated in FIG. 7C, the same effect as the previous embodiment may be achieved. That is, vibration of the compressor may be minimized when the compressor starts.
However, it is extremely difficult to accelerate the velocity of the compressor using the impulse patterns as illustrated in FIGS. 7A, 7B, and 7C. Therefore, hereinafter, an acceleration pattern g(t) of the impulse patterns illustrated in FIGS. 7A, 7B, and 7C, and a general acceleration pattern f(t) are subjected to convolution integral to propose the acceleration pattern for the velocity of the compressor.
In general, the convolution integral as a kind of integral form may be used to acquire an output signal of a linear system for an input signal and an impulse response of the system.
First, the convolution integral is illustrated in Equation 1 below.
[Equation 1]
f(t)* g(t)=∫_∞ ^∞ f(t)g(t−τ)dτ
It has been already demonstrated that a new function acquired through the convolution integral expressed by Equation 1 above has features of the existing f(t) and g(t). When force is excited in two stages as illustrated in FIG. 7A, f(t)=a and g(t)=1/(1+k) (at t=0), and g(t)=k/(1+k) (at t=ΔT). When both functions are subjected to the convolution integral, a result thereof is illustrated as Equation 2 below.
$\begin{matrix} {f (t)}^{*} g (t) = \frac{a}{1 + k} H (t) - \frac{a}{1 + k} H (t - Δ T) + \frac{ak}{1 + k} H (t - T) - \frac{ak}{1 + k} H (t - T - Δ T) k = e^{\frac{- ζ π}{\sqrt{1 - ζ^{2}}}}, Δ T = \frac{π}{ω \sqrt{1 - ζ^{2}}} & [Equation 2] \end{matrix}$
where ω=natural frequency of compressor vibration system,
ζ=damping ratio of compressor vibration system,
a=maximum acceleration of compressor,
T=V/a, V=target operating velocity,
H(x)=unit step function,
H(x)=1 (x≧0), and
H(x)=0 (x<0).
In FIGS. 8A and 8B, Equation 2 above is expressed by graphs. In FIG. 8A, an equation corresponding to area (A) is a/(1+k)*H(t)−a/(1+k)*H(t−Δt) and an equation corresponding to area (B) is ak/(1+k)*H(t−T)−ak/(1+k)H(t−T−ΔT). It can be seen that FIG. 8B is acquired by simply summing up areas (A) and (B).
That is, as illustrated in FIG. 8B, when i) the compressor is accelerated at a/(1+k) from 0 sec to ΔT sec, ii) the compressor is accelerated at a from AT sec to T sec, iii) the compressor is accelerated at ak/(1+k) from T sec to ΔT+T sec, the vibration is generated in the compressor similarly as the case in which the velocity is accelerated as the impulse pattern in two stages as illustrated in FIG. 7A. Therefore, the vibration in the compressor may be reduced when the compressor is accelerated as illustrated in FIG. 8B.
When force is excited in three stages as illustrated in FIG. 7B, f(t)=a and g(t)=1/(1+2k+k²) (at t=0), g(t)=2k/(1+2k+k²) (at t=ΔT), and g(t)=k²/(1+2k+k²) (at t=2ΔT). When both functions are subjected to convolution integral, a result thereof is illustrated as Equation 3 below.
$\begin{matrix} {f (t)}^{*} g (t) = \frac{a}{1 + 2 k + k^{2}} H (t) - \frac{a}{1 + 2 k + k^{2}} H (t - Δ T) + \frac{2 ak}{1 + 2 k + k^{2}} H (t - T) - \frac{2 ak}{1 + 2 k + k^{2}} H (t - T - Δ T) + \frac{{ak}^{2}}{1 + 2 k + k^{2}} H (t - 2 T) - \frac{{ak}^{2}}{1 + 2 k + k^{2}} H (t - 2 T - Δ T) & [Equation 3] \end{matrix}$
where ω=natural frequency of compressor vibration system,
ζ=damping ratio of compressor vibration system,
a=maximum acceleration of compressor,
T=V/a, V=target operating velocity,
H(x)=unit step function,
H(x)=1 (x≧0), and
H(x)=0 (x<0).
That is, even when the velocity of the compressor is accelerated as illustrated in Equation 3, the vibration generated in the compressor may be reduced.
Further, when force is excited in fourth stages as illustrated in FIG. 7C, f(t)=a and g(t)=1/D (at t=0), g(t)=3k/D (at t=ΔT), g(t)=3k²/D (at t=2ΔT), and g(t)=k³/D(at t=3ΔT). When both functions are subjected to the convolution integral, a result thereof is illustrated as Equation 4 below.
$\begin{matrix} {f (t)}^{*} g (t) = \frac{a}{D} H (t) - \frac{a}{D} H (t - Δ T) + \frac{3 ak}{D} H (t - T) - \frac{3 ak}{D} H (t - T - Δ T) + \frac{3 {ak}^{2}}{D} H (t - 2 T) - \frac{3 {ak}^{2}}{D} H (t - 2 T - Δ T) + \frac{k^{3}}{D} H (t - 3 t) - \frac{k^{3}}{D} H (t - 3 T - Δ T) & [Equation 4] \end{matrix}$
where D=(1+k)³.
ω=natural frequency of compressor vibration system,
ζ=damping ratio of compressor vibration system,
a=maximum acceleration of compressor,
T=V/a, V=target operating velocity,
H(x)=unit step function,
H(x)=1 (x≧a0), and
H(x)=0 (x<0).
That is, even when the velocity of the compressor is accelerated as illustrated in Equation 4, vibration generated in the compressor may be reduced.
Embodiments disclosed herein provide a device for reducing vibration in a compressor and a method for reducing vibration that minimize vibration in a compressor when the compressor starts and stops.
Embodiments disclosed herein provide a device for reducing vibration in a compressor that may include a compressor controlled to be operated at a target operating velocity after starting; a power supply unit or power supply that supplies power to the compressor; and a control unit or controller that controls the power supply unit so that a magnitude or a phase of the power supplied to the compressor is changed. The control unit may control the power supply unit so that vibration generated in the compressor is offset because or by an exciting force generated in the compressor within a predetermined time interval multiple times when the compressor starts or when the compressor stops during a target operation velocity operating of the compressor.
Further, the predetermined time interval may correspond to approximately ½ of a natural frequency of the compressor vibration. In addition, when the compressor starts, the multiple times of exciting force may include a first exciting force, and a second exciting force generated after the first exciting force is generated and having a smaller magnitude than the first exciting force. Moreover, the first exciting force may be an exciting force generated by a current applied to the compressor so that the compressor is operated at a first velocity lower than a target operating velocity, and the second exciting force may be an exciting force generated by a current applied to the compressor so that the compressor operated at the first velocity is operated at the target operating velocity. In addition, the first velocity may correspond to approximately ½ of the target operating velocity of the compressor.
Moreover, when the compressor stops, the multiple times of exciting force may include a third exciting force, and a fourth exciting force generated after the third exciting force is generated and having a smaller magnitude than the third exciting force. Further, the third exciting force may be an exciting force generated by a current applied to the compressor so that the compressor is operated at the first velocity lower than the target operating velocity, and the fourth exciting force may be an exciting force generated by a current applied to the compressor so that the compressor operated at the first velocity stops. In addition, the first velocity may correspond to approximately ½ of the target operating velocity of the compressor.
Further, the multiple times of exciting force may be generated by an impulse current supplied to the compressor.
A device for reducing vibration in a compressor according to another embodiment may include a compressor constituting a refrigeration cycle and operable at a target operating velocity; a power supply unit or power supply that supplies power to the compressor; and a control unit or controller that controls the power supply unit so that a magnitude or a phase of the power supplied to the compressor is changed. The control unit may control the power supply unit so that the compressor is accelerated or decelerated to a first velocity which is less than the target operating velocity when the compressor starts or when the compressor stops while being operated at the target operating velocity.
Further, the control unit may control the power supply unit so that the compressor is primarily accelerated up to the first velocity, and thereafter, secondarily accelerated up to the target operating velocity after a predetermined time elapsed when the compressor starts. Further, the predetermined time may correspond to approximately ½ of a natural frequency of the compressor vibration.
In addition, the control unit may control the power supply unit so that the compressor is primarily decelerated down to the first velocity from the target operating velocity, and thereafter, stops after a predetermined time elapsed when the compressor stops. Further, the predetermined time may correspond to approximately ½ of a natural frequency of the compressor vibration. Moreover, the first velocity may be a velocity which is half of the target operating velocity.
A method for reducing vibration in a compressor according to yet another embodiment may include primarily accelerating a stopped compressor up to a first velocity; and secondarily accelerating the compressor up to a target operating velocity. A time as long as approximately ½ of a natural frequency of the compressor vibration from a primary acceleration start time of the compressor up to a secondary acceleration start time of the compressor. Moreover, the first velocity may be a velocity which is approximately half of the target operating velocity.
In addition, the method may further include primarily decelerating the compressor operated at the target operating velocity down to the first velocity; and secondarily decelerating the compressor to be completely stopped. Further, a time as long as approximately 1/2 of a natural frequency of the compressor vibration may elapse from a primary deceleration start time of the compressor up to a secondary deceleration start time of the compressor.
Moreover, a first exciting force of the compressor generated in the primary acceleration may be larger than a second exciting force of the compressor generated in the secondary acceleration, and a third exciting force of the compressor generated in the primary deceleration may be larger than a fourth exciting force of the compressor generated in the secondary deceleration.
According to embodiments disclosed herein, vibration generated in a compressor may be minimized when the compressor starts and stops. Therefore, stress generated in a pipe connected with the compressor may be minimized, and as a result, breakage of the pipe may be prevented.
Although embodiments have been described above, embodiments are not limited to the aforementioned specific embodiments. That is, various changes and modifications can be made without departing from the spirit and the scope of the appended claims by those skilled in the art, and it should be understood that equivalents of all appropriate changes and modifications belong to the scope.
Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments.
Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.

Claims

What is claimed is:

1. A device for reducing vibration in a compressor, comprising:

a compressor controlled to be operated at a target operating velocity after starting;

a power supply that supplies power to the compressor; and

a controller that controls the power supply so that a magnitude or a phase of the power supplied to the compressor is changed, wherein the controller controls the power supply so that vibration generated in the compressor is offset by an exciting force generated in the compressor within a predetermined time interval multiple times when the compressor starts or when the compressor stops.

2. The device of claim 1, wherein the predetermined time interval corresponds to approximately half of a period of a natural frequency of the vibration.

3. The device of claim 1, wherein when the compressor starts, the generation of the exciting force multiple times includes a first exciting force, and a second exciting force generated after the first exciting force and having a smaller magnitude than the first exciting force.

4. The device of claim 3, wherein the first exciting force is an exciting force generated by a current applied to the compressor so that the compressor is operated at a first velocity, which is lower than the target operating velocity, and the second exciting force is an exciting force generated by a current applied to the compressor so that the compressor currently being operated at the first velocity is operated at the target operating velocity.

5. The device of claim 4, wherein the first velocity corresponds to approximately half of the target operating velocity of the compressor.

6. The device of claim 1, wherein when the compressor stops, the generation of the exciting force multiple times includes a third exciting force, and a fourth exciting force generated after the third exciting force and having a smaller magnitude than the third exciting force.

7. The device of claim 6, wherein the third exciting force is an exciting force generated by a current applied to the compressor so that the compressor is operated at a first velocity, which is lower than the target operating velocity, and the fourth exciting force is an exciting force generated by a current applied to the compressor so that the compressor currently being operated at the first velocity stops.

8. The device of claim 7, wherein the first velocity corresponds to approximately half of the target operating velocity of the compressor.

9. The device of claim 1, wherein the generation of the exciting force multiple times is accomplished by an impulse current supplied to the compressor.

10. A device for reducing vibration in a compressor, comprising:

a compressor of a refrigeration cycle and operable at a target operating velocity;

a power supply that supplies power to the compressor; and

a controller that controls the power supply so that a magnitude or a phase of the power supplied to the compressor is changed, wherein the controller controls the power supply so that the compressor is accelerated or decelerated to a first velocity, which is less than the target operating velocity, when the compressor starts or when the compressor stops.

11. The device of claim 10, wherein the controller controls the power supply so that the compressor is primarily accelerated to the first velocity, and after a predetermined time has elapsed, secondarily accelerated to the target operating velocity when the compressor starts.

12. The device of claim 11, wherein the predetermined time corresponds to approximately half of a period of a natural frequency of the vibration.

13. The device of claim 10, wherein the controller controls the power supply so that the compressor is primarily decelerated to the first velocity from the target operating velocity, and after a predetermined time has elapsed, stops when the compressor stops.

14. The device of claim 13, wherein the predetermined time corresponds to approximately half of a period of a natural frequency of the vibration.

15. The device of claim 10, wherein the first velocity is a velocity which is half of the target operating velocity.

16. A method for reducing vibration in a compressor, comprising:

primarily accelerating a stopped compressor to a first velocity; and

secondarily accelerating the compressor to a target operating velocity, wherein a time as long as approximately half of a period of a natural frequency of compressor vibration has elapsed from a primary acceleration start time of the compressor to a secondary acceleration start time of the compressor.

17. The method of claim 16, wherein the first velocity is a velocity which is approximately half of the target operating velocity.

18. The method of claim 16, further comprising:

primarily decelerating the compressor currently operated at the target operating velocity to the first velocity; and

secondarily decelerating the compressor to be completely stopped.

19. The method of claim 18, wherein a time as long as approximately half of a natural frequency of the compressor vibration elapses from a primary deceleration start time of the compressor to a secondary deceleration start time of the compressor.

20. The method of claim 18, wherein a first exciting force of the compressor generated in the primary acceleration is larger than a second exciting force of the compressor generated in the secondary acceleration, and a third exciting force of the compressor generated in the primary deceleration is larger than a fourth exciting force of the compressor generated in the secondary deceleration.