Patent ID: 12222145

MODE FOR INVENTION

The above-mentioned objects, features, and advantages of the present disclosure are described in detail with reference to accompanying drawings. A person having ordinary knowledge in the art to which the present disclosure pertains may easily embody the technical idea of the present disclosure. A detailed description of a well-known technology relating to the present disclosure may be omitted if it unnecessarily obscures the gist of the present disclosure.

Hereinafter, preferred embodiments according to the present disclosure are described in detail with reference to the accompanying drawings. In the drawings, same reference numerals can be used to refer to same or similar components.

FIG.1is a front view showing an interior of a refrigerator according to an embodiment of the present disclosure.

Referring toFIG.1, the refrigerator according to an embodiment of the present disclosure includes a main body40having a freezing room31and a refrigerating room32, and doors35L and35R connected to the main body40by a hinge to open and close the freezing room31and the refrigerating room32.

The freezing room31and the refrigerating room32are separated by a partition wall disposed in the main body40to prevent cold air flow and a freezing room evaporator and a refrigerating room evaporator are disposed in the freezing room31and the refrigerating room32to cool spaces thereof.

FIG.2is a perspective view showing devices of the refrigerator ofFIG.1.

As shown inFIG.2, the refrigerator according to an embodiment of the present disclosure includes a compressor100, a condenser110to condense refrigerant compressed by the compressor100, a freezing room evaporator124disposed in the freezing room31to receive the refrigerant condensed by the condenser110and evaporate the refrigerant, a refrigerating room evaporator122disposed in a refrigerating room32to receive the refrigerant condensed by the condenser110and evaporate the refrigerant, a 3 way valve130which is a refrigerant control valve to supply the refrigerant condensed by the condenser110to the refrigerating room evaporator122or the freezing room evaporator124, a refrigerating room expansion valve132to expand the refrigerant supplied to the refrigerating room evaporator122, and a freezing room evaporator124.

A refrigerating room fan142is disposed in the refrigerating room32to improve heat exchange efficiency of the refrigerating room evaporator122and circulate air inside of the refrigerating room32. In addition, a freezing room fan144is disposed in the freezing room31to improve heat exchange efficiency of the freezing room evaporator124and circulate the air inside of the freezing room31.

In addition, a check valve is disposed at a discharge side of the refrigerating room evaporator122to prevent flow of the refrigerant from the freezing room evaporator124.

In short, the refrigerator shown inFIGS.1and2has a 1COM-2EVA system in which the refrigerating room32and the freezing room31are independently cooled by respective evaporators122and124.

The 3 way valve130may select and open and close a flow path of the refrigerant supplied from the condenser110, and may open or close either the refrigerating room expansion valve132or the freezing room expansion valve134.

Meanwhile, in this embodiment, the 3 way valve130may be disposed, but instead of the 3 way valve130, an opening/closing valve may be disposed in each of pipes connected to the refrigerating room evaporator122and the freezing room evaporator124.

Meanwhile, the refrigerator may include an outside air temperature sensor to sense an outside air temperature, a refrigerating room temperature sensor to sense a temperature of the refrigerating room, and a freezing room temperature sensor to detect the temperature of the freezing room.

The outside air temperature sensor detects the outside temperature of the refrigerating room32and the freezing room31. The outside air temperature sensor may detect the temperature of outside air (i.e., outside air) suctioned into a machine room. The refrigerating room temperature sensor is disposed inside of the refrigerating room32to detect the temperature inside of the refrigerating room32. The freezing room temperature sensor is disposed inside of the freezing room31to detect the temperature inside of the freezing room31.

FIG.3is a control block diagram of a refrigerator according to an embodiment of the present disclosure.

Referring toFIG.3, the refrigerator may further include an input unit150to input a desired refrigerating room temperature or a desired freezing room temperature. The input unit150may be disposed in a main body40, and a user may input the desired refrigerating room temperature or the desired freezing room temperature by manipulating the input unit150. When an additional operation is not performed using the input unit150, the refrigerator may be operated based on a desired refrigerating room temperature or a desired freezing room temperature set at a time of manufacturing thereof.

The refrigerator may further include a condensing fan160. The condensing fan160is disposed adjacent to the condenser110and may blow outside air from the main body40to the condenser110.

The refrigerator may further include a controller180to control a compressor100, a 3 way valve130, a condensing fan160, a refrigerating room fan142, and a freezing room fan144. The controller180may be a processor-based device. The processor may include one or more of a central processing unit, an application processor, or a communication processor.

Meanwhile, the controller180may include a main controller and a compressor controller. The compressor controller and the main controller may each transmit and receive various pieces of information through bidirectional communication.

The controller180may determine the refrigerating room temperature satisfaction/dissatisfaction based on the temperature detected by the refrigerating room temperature sensor172. If the temperature detected by the refrigerating room temperature sensor172is within a refrigerating room temperature satisfaction range, the controller180may determine a state of temperature detected by the refrigerating room temperature sensor172as a refrigerating room temperature satisfaction state. If the temperature detected by the refrigerating room temperature sensor172is within a refrigerating room temperature dissatisfaction range, the controller180may determine a state of the temperature detected by the refrigerating room temperature sensor172as a refrigerating room temperature dissatisfaction state. The refrigerating room temperature satisfaction range may be set lower than the refrigerating room temperature dissatisfaction range. The refrigerating room temperature satisfaction range and the refrigerating room temperature dissatisfaction range may be set based on a refrigerating room reference temperature set at the time of manufacturing of the refrigerator or a desired refrigerating room temperature input by a user. The controller180may control the compressor100, the 3 way valve130, the condensing fan160, and the refrigerating room fan142to adjust the refrigerating room temperature to be within the refrigerating room temperature satisfaction range and this operation may be a refrigerating room operation.

The controller180may determine the freezing room temperature satisfaction/dissatisfaction based on the temperature detected by freezing room temperature sensor173. If the temperature detected by freezing room temperature sensor173is within the freezing room temperature satisfaction range, the controller180may determine a state of the temperature detected by freezing room temperature sensor173as a freezing room temperature satisfaction state. If the temperature detected by freezing room temperature sensor173is within the freezing room temperature dissatisfaction range, the controller180may determine a state of the temperature detected by freezing room temperature sensor173as the freezing room temperature dissatisfaction state. The freezing room temperature satisfaction range may be set lower than the freezing room temperature dissatisfaction range. The freezing room temperature satisfaction range and the freezing room temperature dissatisfaction range may be set based on a freezing room reference temperature set at the time of manufacturing of the refrigerator or a desired freezing room temperature input by the user. The controller180may control the compressor100, the 3 way valve130, the condensing fan160, and the freezing room fan144to adjust the freezing room temperature to be within the freezing room temperature satisfaction range and the operation may be a freezing room operation.

The controller180may drive the compressor100, control the 3 way valve130to be in refrigerating room cooling mode, and drive the condensing fan160and the refrigerating room fan142when the refrigerating room temperature is within the dissatisfaction range in a state in which the compressor100is stopped or the refrigerator is in an initial operation state in which power is applied to the refrigerator.

When the compressor100is driven, the 3 way valve130is in the refrigerating room cooling mode, and the condensing fan160and the refrigerating room fan142are driven, the refrigerant may circulate through the compressor100, the condenser110, the refrigerating room expansion valve132, and the refrigerating room evaporator122, the refrigerating room fan142may circulate cold air of the refrigerating room32to the refrigerating room evaporator122and the refrigerating room32, and the refrigerator may perform a refrigerating room operation to cool the refrigerating room32.

When the refrigerating room temperature detected by the refrigerating room temperature sensor172reaches the refrigerating room temperature satisfaction range, the controller180may stop the refrigerating room fan142and complete the refrigerating room operation.

When the refrigerating room operation is completed, the controller180may perform a freezing room operation, control the 3 way valve130in a freezing room cooling mode, and drive the freezing room fan82. The compressor100and the condensing fan160may be driven in the freezing room cooling mode of the 3 way valve130.

When the compressor100is driven, the 3 way valve130is in the freezing room cooling mode, and the condensing fan160and the freezing room fan144are driven, the refrigerant may circulate through the compressor100, the condenser110, the freezing room expansion valve134, and the freezing room evaporator124and the freezing room fan144may circulate the cold air of the freezing room31to the freezing room evaporator124and the freezing room31and the refrigerator may perform the freezing room operation to cool the freezing room31.

When the freezing room temperature detected by freezing room temperature sensor173reaches the freezing room temperature satisfaction range, the controller180may stop the freezing room fan144and complete the freezing room operation.

When the freezing room operation is completed, the controller180may perform a refrigerant recovery operation and control the 3 way valve130to be in a refrigerant recovery mode. In the refrigerant recovery mode, the 3 way valve130may close an inlet or close both a first outlet and a second outlet. Therefore, in the refrigerant recovery mode, the refrigerant does not flow from the condenser110to each of the refrigerating room evaporator122and the freezing room evaporator124, and the refrigerant in the refrigerating room evaporator122and the remaining refrigerant in the freezing room evaporator124may be suctioned into the compressor100based on the driving of the compressor100and may be moved to the compressor100.

When a refrigerant recovery operation termination condition is satisfied after the refrigerant recovery operation is performed, the controller180may terminate the refrigerant recovery operation. The conditions for terminating the refrigerant recovery operation are described below in more detail.

After the refrigerant recovery operation is terminated, the controller180may determine whether to start the refrigerating room operation based on the temperature detected by the refrigerating room temperature sensor172, and if the temperature detected by the refrigerating room temperature sensor172is in the refrigerating room temperature dissatisfaction range, the controller180may start the refrigerating room operation.

Meanwhile, embodiments of the present disclosure may be applied to a reciprocating compressor including a piston. The reciprocating compressor compresses refrigerant based on a reciprocating motion of the piston. Further, embodiments of the present disclosure may be applied to an oilless compressor using refrigerant as a lubricant for a piston. That is, embodiments of the present disclosure may be applied to an oilless reciprocating compressor.

Hereinafter, a structure of the above-described compressor is described in detail with reference toFIGS.4and5.

FIG.4shows a structure of a compressor100according to an embodiment of the present disclosure.

Referring toFIG.4, the compressor100may be a linear compressor, which is an example of reciprocating compressor.

The compressor100includes a cylinder420disposed inside of a shell401, a piston430to linearly reciprocate within the cylinder420, and a motor assembly440as a linear motor to provide a driving force to the piston430. When the motor assembly440is driven, the piston430may reciprocate in an axial direction.

The compressor100further includes a suction muffler450coupled to the piston430and to reduce noise generated from refrigerant suctioned through a suction pipe404. The refrigerant suctioned through the suction pipe404flows into the piston430through the suction muffler450.

The suction muffler450includes a first muffler451, a second muffler452, and a third muffler453coupled to one another.

The first muffler451is disposed inside of the piston430and the second muffler452is coupled to a rear side of the first muffler451. The third muffler453accommodates the second muffler452and may extend to the rear side of the first muffler451. From the viewpoint of a flow direction of the refrigerant, the refrigerant suctioned through the suction pipe404may sequentially pass through the third muffler453, the second muffler452, and the first muffler451.

The suction muffler450further includes a muffler filter455. The muffler filter455may be disposed at a boundary surface where the first muffler451and the second muffler452are coupled to each other.

Meanwhile, the term “axial direction” may be understood as a reciprocating direction of the piston430, that is, a transverse direction inFIG.4. In the “axial direction”, a direction toward a compression space (P) from the suction pipe404, that is, a flowing direction of the refrigerant is referred to as “a forward direction” and the opposite direction thereof is referred to as “a rearward direction”. When the piston430moves in the forward direction, the compression space (P) may be compressed. Meanwhile, “a radial direction” is a direction perpendicular to the reciprocating direction of the piston430and may be understood as a vertical direction ofFIG.4.

The piston430includes a substantially cylindrical piston body431and a piston flange432that extends from the piston body431in the radial direction. The piston body431may reciprocate inside the cylinder420and the piston flange432may reciprocate at an outside of the cylinder420.

The cylinder420includes a cylinder body421that extends in the axial direction and a cylinder flange422disposed outside of a front portion of the cylinder body421. In addition, the cylinder420accommodates at least a portion of the first muffler451and at least a portion of the piston body431.

A gas inlet426to which at least a portion of the refrigerants discharged through a discharge valve461described below is introduced is defined in the cylinder body421. The gas inlet426may penetrate a radial inner portion thereof from an outer circumferential surface of the cylinder body421.

A filter assembly500is disposed in the gas inlet426. The filter assembly500includes a filter member to filter foreign matters or oil contained in the refrigerant gas. In addition, a flow rate of the refrigerant passing through the filter member is adjusted using a nozzle disposed in the filter assembly500. The filter member functions as a gas bearing between the piston430and the cylinder420.

Further, the cylinder420includes the compression space (P) in which the refrigerant is compressed by the piston430. In addition, a suction hole433for introducing refrigerant into the compression space (P) is defined at a front side of the piston body431and a suction valve435is disposed at a front side of the suction hole433to selectively open the suction hole433.

In addition, a fastening hole436ato which a predetermined fastening member436is coupled is defined at the front side of the piston body431. The fastening member436is coupled to the fastening hole436athrough the suction valve435and couples the suction valve435to the front side of the piston body431.

A discharge cover460including a discharge space460aof the refrigerant discharged from the compression space (P) and discharge valve assemblies461and463coupled to the discharge cover460and to selectively discharge the refrigerant compressed in the compression space (P) are disposed in front of the compression space (P).

The discharge valve assemblies461and463include the discharge valve461that is opened when a pressure inside the compression space (P) is equal to or greater than a discharge pressure, and to introduce the refrigerant to the discharge space460aof the discharge cover460and a spring assembly463disposed between the discharge valve461and the discharge cover460and to provide an elastic force in the axial direction. The spring assembly463includes a valve spring463aand a spring supporter463bto support the valve spring463aon the discharge cover460.

The discharge valve461is coupled to the valve spring463aand a rear portion or a rear surface of the discharge valve461is supported on a front surface of the cylinder420. When the discharge valve461is supported on the front surface of the cylinder420, the compression space (P) remains closed, and when the discharge valve461is separated from the front surface of the cylinder420, the compression space (P) is opened and the refrigerant compressed in the compression space (P) may be discharged. The compression space (P) is provided between the suction valve435and the discharge valve461.

In the process of linear reciprocation of the piston430inside the cylinder420, when a pressure in the compression space (P) is less than the discharge pressure and is equal to or less than the suction pressure, the suction valve435is opened to suction the refrigerant into the compression space (P). If the pressure in the pressure space (P) is equal to or greater than the suction pressure, the refrigerant in the compression space (P) is compressed when the suction valve435is closed.

In addition, when the pressure in the compression space (P) is equal to or greater than the discharge pressure, the valve spring463ais deformed in the forward direction to open the discharge valve461, and the refrigerant is discharged to the discharge space460afrom the compression space (P). After the refrigerant is discharged, the valve spring463aprovides a restoring force to the discharge valve461to close the discharge valve461.

The compressor100further includes a frame410. The frame410fixes the cylinder420. For example, the cylinder420may be press-fit into the frame410.

The frame410includes a frame body411having a substantially cylindrical shape and a frame flange412that extends from the frame body411in the radial direction. The frame body411surrounds the cylinder420. That is, the cylinder420may be accommodated inside the frame body411. In addition, the frame flange412may be coupled to the discharge cover460.

The motor assembly440includes an outer stator441, an inner stator448spaced apart from the outer stator441in an inward direction of the outer stator441, and a magnet446disposed in a space between the outer stator441and the inner stator448.

The magnet446may linearly reciprocate by an electromagnetic force between the outer stator441and the inner stator448. The inner stator448is coupled to an outer circumference of the frame body411. The outer stator441includes coil winding bodies441b,441c, and441dand a stator core441a. The coil winding bodies441b,441c, and441dinclude a bobbin441band a coil441cwound in a circumferential direction of the bobbin.

In addition, the compressor100further includes a plurality of resonance springs476aand476bhaving natural frequencies adjusted to resonate the piston430. The driver reciprocating in the compressor100may be stably moved based on operations of the plurality of resonance springs476aand476band vibration or noise occurring based on the movement of the driver may be reduced.

In short, the compressor100described with reference toFIG.4includes the compression space to which working gas is suctioned and discharged between the piston430and the cylinder420, and the piston430linearly reciprocates inside of the cylinder and compresses the refrigerant.

FIG.5shows relation between an operation and a force of the compressor100ofFIG.4. In this case, m is a mass of a piston430, kmis an elastic modulus of springs476aand476b, A is a cross-sectional area of a bore, αi is a constant related to a counter electromotive force of the compressor100, i is a current applied to the compressor100, and Cfis attenuation coefficient of the compressor100.

FIG.6shows a schematic configuration of an operation control device of a compressor100according to an embodiment of the present disclosure.

Referring toFIG.6, the operation control device of the compressor100includes a reciprocating compressor (L.COMP) to change stroke based on a vertical motion of a piston430by a voltage applied to a motor (M) according to a stroke command value and adjust a cooling power, a current detector620and a voltage detector630to detect a current and a voltage generated in the reciprocating compressor (L.COMP) as the stroke is increased by the applied voltage, a microcomputer640to calculate a stroke based on the voltage and the current detected by the current detector620and the voltage detector630, compare the stroke with the stroke command value, and output a switching control signal, and an electric circuit610to shut off alternating power using Triac (Tr1) based on the switching control signal output from the microcomputer640and apply the voltage to the reciprocating compressor (L.COMP).

The reciprocating compressor (L.COMP) vertically moves the piston430by the applied voltage according to the stroke command value set by the user, changes the stroke, and adjusts the cooling power.

The stroke is increased as a turn-on period of the Triac (Tr1) of an electric circuit610is lengthened based on the switching control signal of the microcomputer640. In this case, the current detector620and the voltage detector630detect the current and the voltage applied to the motor (M) of the reciprocating compressor (L. COMP) and apply the current and the voltage to the microcomputer640.

The microcomputer640calculates the stroke based on the applied current and voltage detected by the current detector620and the voltage detector630, and then compares the stroke with the stroke command value to output a switching control signal.

That is, when the calculated stroke is less than the stroke command value, the microcomputer640outputs the switching control signal to lengthen the turn-on period of the Triac (Tr1) and increases a voltage applied to the reciprocating compressor (L.COMP). Further, when the calculated stroke is greater than the stroke command value, the microcomputer640outputs a switching control signal to shorten the turn-on period of the Triac (Tr1) to reduce the voltage applied to the reciprocating compressor (L.COMP).

FIG.7shows a schematic configuration of an operation control device of a compressor100according to another embodiment of the present disclosure.

Referring toFIG.7, the operation control device of the compressor100is a stroke control device of a reciprocating compressor and includes a current detector710, a stroke detector711, a phase difference detector720, a comparator730, a stable area storage portion740, an operation frequency determiner750, a stroke command value determiner760, a frequency/stroke storage portion770, a controller780, and an inverter790.

The current detector710detects a current flowing through a motor. The stroke detector711detects a current stroke of a piston based on a voltage and a current applied to the motor. The phase difference detector720receives the piston stroke detected by the stroke detector711and a motor current detected by the current detector710to detect a phase difference. The stable area storage portion740detects and stores a phase difference stable area to perform a stable operation. The comparator730compares whether the phase difference detected by the phase difference detector720is included in the phase difference stable area. The operation frequency determiner750increases or decreases a reference operation frequency by a predetermined frequency unit, and when the phase difference between the current and the piston stroke is in the stable area, the operation frequency determiner750determines a frequency at that time point as the operation frequency based on a comparison signal of the comparator730. The stroke command value determiner760determines a stroke command value based on the operation frequency output from the operation frequency determiner750. The frequency/stroke storage portion770stores a piston stroke for each operation frequency. The controller780compares the stroke command value with the current stroke of the piston and outputs a stroke control signal based on the comparison. The inverter790changes a voltage applied to the motor by varying the operation frequency based on the stroke control signal output from the controller780.

In more detail, the stroke control device of the compressor detects an inflection point of the phase difference between the piston stroke and the current, and varies the operation frequency to drive the motor in the stable area. That is, the current detector710detects a current applied to the motor, applies the current to the phase difference detector200, and the stroke detector711detects a piston stroke based on the voltage and current applied to the motor.

The phase difference detector720detects a phase difference between the power supply voltage and the motor current, a phase difference between the motor current and the motor voltage, a phase difference between the motor speed and the motor current, or a phase difference between a motor acceleration and the motor current and controls the motor to be driven in the stable area.

The stable area storage portion740detects and stores an area having a value less than ±δ (a predetermined value) based on the phase difference between the motor current and the piston stroke, the motor current and the piston speed, the motor current and the piston acceleration, or the motor current and the motor voltage when mechanical resonance occurs.

The comparator730receives the phase difference between the piston stroke and the current detected by the phase difference detector720, compares whether the phase difference is included in the safety area of the stable area storage portion740, and applies a comparison signal to the operation frequency determiner750.

The operation frequency determiner750increases or decreases the reference operation frequency by a predetermined frequency unit, and when the phase difference between the current and the piston stroke is included in the stable area, the operation frequency determiner750determines a frequency at that time point as the operation frequency based on the comparison signal of the comparator730and applies it to the stroke command value determiner760.

The stroke command value determiner760determines a stroke command value based on the operation frequency output from the operation frequency determiner750.

That is, the frequency/stroke storage portion770to store the piston stroke for each frequency reads the piston stroke corresponding to the operation frequency output from the operation frequency determiner750and determines the piston stoke as a stroke command value.

The controller780receives the stroke command value output from the stroke command value determiner760, compares the stroke command value with the piston stroke of the stroke detector711, and outputs a stroke control signal. That is, the comparator712compares the stroke command value with the piston stroke, outputs a difference value and the stroke controller713applies the corrected stroke control signal to the inverter790based on the difference value.

The inverter790changes the voltage applied to the motor by varying the operation frequency based on the stroke control signal output from the controller780.

Hereinafter, a method for controlling a refrigerator is described in detail with reference to the above matters.

FIGS.8to10show a flow of refrigerant during a cooling operation of a refrigerator according to an embodiment of the present disclosure.

Referring toFIGS.8to10, a 3 way valve130includes an inlet130aand two outlets130band130c. The first outlet130bamong the two outlets130band130cmay be connected to a refrigerating room expansion tube132and the second outlet130camong the two outlets130band130cmay be connected to a freezing room expansion tube134.

Referring toFIG.8, the 3 way valve130may be controlled in a first mode in which the inlet130acommunicates with the first outlet130band a space between the inlet130aand the second outlet130cis closed. The first mode corresponds to a mode in which refrigerant flows to a refrigerating room evaporator122, that is, a refrigerating room cooling mode.

Referring toFIG.9, a 3 way valve130may be controlled in a second mode in which an inlet130acommunicates with a second outlet130cand a space between the inlet130aand a first outlet130bis closed. The second mode corresponds to a mode in which refrigerant flows to a freezing room evaporator124, that is, a freezing room cooling mode.

Referring toFIG.10, a 3 way valve130may be controlled in a third mode in which an inlet130ais closed or a first outlet130band a second outlet130care closed. The third mode may be a mode in which refrigerant does not flow to a refrigerating room evaporator122and a freezing room evaporator124, that is, a refrigerant recovery mode.

FIG.11is a line diagram of a method for controlling an operation of the refrigerator ofFIGS.8to10.

InFIG.11, valve R is a flow path of a 3 way valve130at a refrigerating room side, valve F is a flow path of the 3 way valve130at a freezing room side, and opening and closing of the flow path at the refrigerating room side is referred to as “turn-on/turn-off of the valve R” and opening and closing of the flow path at the freezing room side is referred to as “on/off of the valve F”.

Referring toFIG.11, a refrigerating room operation, a freezing room operation, and a refrigerant recovery operation are sequentially performed.

During the operation of the refrigerating room, when a compressor100is operated, the valve R is turned on and the valve F is turned off. In this case, refrigerant flows from a condenser110to a refrigerating room expansion valve132and a refrigerating room evaporator122, a condensing fan160and a refrigerating room fan142are driven, and a freezing room fan144is not driven.

Subsequently, during the operation of the freezing room, when the compressor100is driven, the valve F is turned on and the valve R is turned off. In this case, the refrigerant flows from the condenser110to a freezing room expansion valve134and a freezing room evaporator124, the condensing fan160and a freezing room fan144are driven, and the refrigerating room fan142is not driven.

Subsequently, during the refrigerant recovery operation, while the compressor100is driving, both the valve R and the valve F are turned off. In this case, the refrigerant does not flow from the condenser to each of the refrigerating room evaporator122and the freezing room evaporator124. That is, the refrigerant supply to the refrigerating room and freezing room evaporators122and124is blocked.

In addition, the driving of the freezing room fan144during the freezing room operation, which is a previous operation to the refrigerant recovery operation, is maintained. For example, the freezing room fan144is driven at a low speed.

The residual refrigerant inside of the freezing room evaporator124is evaporated by the operation of the freezing room fan144, and a pressure inside of the freezing room evaporator124is increased by heat exchange. The refrigerant in the freezing room evaporator124flows toward the compressor100.

In addition, as the refrigerating room evaporator122has not been driven until the refrigerant recovery operation, the pressure of the refrigerating room evaporator122is higher than that of the freezing room evaporator124without additionally driving the refrigerating room fan142. Therefore, the residual refrigerant inside of the refrigerating room evaporator122is smoothly moved to the compressor100by driving the compressor100.

In particular, during the cooling recovery operation, the freezing room fan144is driven when the driving of the condensing fan160is stopped. That is, if the condensing fan160is driven, internal pressure of the condenser110is increased, thereby causing an adverse effect when recovering the refrigerant, so the condensing fan160is not driven.

Meanwhile, the embodiment in which the refrigerant recovery operation is performed after the freezing room operation is described hereinabove, but the above configuration may be similarly performed even when the refrigerant recovery operation is performed after the refrigerating room operation. In addition, even when the refrigerating room operation and the freezing room operation are simultaneously performed, the above configuration may be similarly performed.

Hereinafter, a configuration of determining an end time point of the refrigerant recovery operation is described in more detail with reference to drawings below.

As described above, the compressor converts mechanical energy into compressive energy of compressible fluid. In particular, a reciprocating compressor includes a compression space between the piston and the cylinder to suction and discharge working gas, and the piston linearly reciprocates inside the cylinder to compress refrigerant.

In this case, the operation of the reciprocating compressor may be modeled as shown inFIG.5and Equation 1.

Power=F×xt[Equation⁢1]F=α⁢i=m⁢d2⁢xdt2+Cf⁢dxdt+Km⁢x+A⁡(Pd-Ps)

Power is a driving input value (i.e., power or energy) applied to a compressor, F is a force of the compressor, x is a stroke of the piston of the compressor, t is time, α is a constant related to a counter electromotive force of the compressor, i is a current applied to the compressor, m is a mass of the piston of the compressor, Cfis attenuation coefficient of the compressor, Kmis an elastic modulus of the spring of the compressor, A is a cross-sectional area of a bore, Pa is the discharge pressure of a compressor, and Psis a suction pressure of the compressor.

Referring to Equation 1, when the stroke (x) of the piston is fixed as a constant, it can be seen that a driving power (Power) applied to the compressor is proportional to a difference (ΔP) between the discharge pressure (Pd) and the suction pressure (Ps) of the compressor (Power ∝ΔP).

The above relation is described in more detail as follows.

FIG.12is a graph showing relation between a driving power applied to a compressor during a refrigerant recovery operation and a difference (ΔP) between a discharge pressure (Pd) and a suction pressure (Ps) of the compressor.

The upper graph ofFIG.12is derived from a simulation of the refrigerant recovery operation performed by the present inventor. In the simulation, temperature sensors were placed at a suction end and a discharge end of the compressor to measure temperatures of the suction end and the discharge end of the compressor, and a driving current and a driving voltage applied to the compressor were measured. In addition, the simulation was performed when a stroke (x) of the compressor (a piston) was fixed. In this case, as the temperatures of the suction end and the discharge end of the compressor are proportional to pressures of the suction end and the discharge end of the compressor (refer to an ideal gas state equation), the lower graph ofFIG.12is obtained by replacing the temperature with the pressure.

Referring toFIG.12, a driving power (derived from a current and a voltage) applied to the compressor before and after a start of the refrigerant recovery operation, and the temperature/pressure at the suction end and the discharge end of the compressor have substantially constant values.

In addition, when the refrigerant recovery operation is terminated, an amount of refrigerant suctioned into the compressor is reduced. In this case, a difference in temperature/pressure between the suction end and the discharge end is decreased, and thus, the driving power applied to the compressor is decreased. For example, the temperature/the pressure of the suction end and the discharge end of the compressor converge to a value, and a difference in temperature/pressure between the suction end and the discharge end becomes “0. In addition, the compressor performs no-load operation.

In short, when the refrigerant recovery operation starts and the refrigerant remains inside of the evaporators, the difference in temperature/pressure between the suction end and the discharge end is almost unchanged. However, when the refrigerant is almost suctioned into the evaporators, the difference in temperature/pressure between the suction end and the discharge end decreases, the compressor smoothly performs no-load operation, and the driving power applied to the compressor decreases.

Therefore, according to an embodiment of the present disclosure, an end time point of the refrigerant recovery operation may be determined based on the driving power applied to the compressor100during the refrigerant recovery operation, that is, the driving input value.

FIG.13is a flowchart of a method for controlling a refrigerator according to an embodiment of the present disclosure.

As described above, the refrigerator performs a series of tasks to lower a temperature of an object to be cooled such as food and may include a compressor100, an operation control device of the compressor100, a condenser110, a refrigerator expansion tube132, a freezer expansion tube134, a refrigerating room evaporator122, a freezing room evaporator124, a 3 way valve130, and a main controller. In this case, the steps ofFIG.13may be performed by a compressor controller of the operation control device of the compressor100.

In addition, the method for controlling the refrigerator may be performed based on operation information of the compressor100. An example of operation information of the compressor100is as shown inFIG.14. In particular, the method for controlling the refrigerator may be performed based on a driving input value or a driving power value of the compressor100.

Meanwhile, before a start step ofFIG.13, whether a condition of a refrigerant recovery operation of recovering the refrigerant by the refrigerating room evaporator122and the freezing room evaporator124is satisfied may be determined.

For example, the condition of the refrigerant recovery operation may correspond to a condition in which a temperature of each of a freezing room31and a refrigerating room32satisfies a target temperature range of each of the freezing room and the refrigerating room after cooling the freezing room31. That is, in general, a pressure and a temperature of the refrigerating room evaporator122are higher than those of the freezing room evaporator124, and the refrigerant recovery operation may be performed after a second cooling operation when a first cooling operation by the refrigerating room evaporator122and the second cooling operation by the freezing room evaporator124are sequentially performed.

When the conditions of the refrigerant recovery operation are satisfied, it is assumed that the refrigerant recovery operation is started. In addition, it is assumed that a current detector and a voltage detector detect a driving current and a driving voltage applied to the compressor100in real time during a preset period of time and transmit them to a compressor controller, and the compressor controller detects a driving power applied to the compressor100based on the driving current and the driving voltage.

Hereinafter, the operation of the refrigerator performing the refrigerant recovery operation is described in more detail with reference toFIG.13.

At S10, a minimum operation time period and a maximum operation time period of refrigerant recovery are set.

The minimum operation time period of the refrigerant recovery (i.e., the minimum refrigerant recovery operation time period) refers to a time period for which the compressor100performs the refrigerant recovery operation at a minimum degree. In addition, the maximum operation time period of the refrigerant recovery (that is, the maximum refrigerant recovery operation time period) refers to a time period for which the compressor100performs the refrigerant recovery operation at a maximum degree.

In particular, it is possible to prevent abrasion of the piston430of the compressor100using the refrigerant as a lubricant by setting the minimum refrigerant recovery operation time period.

In more detail, the compressor100according to the present disclosure is an oilless compressor to lubricate between the piston430and the cylinder420using refrigerant gas. The refrigerant recovery operation may be terminated when the refrigerant is not sufficiently returned to the compressor100according to the operation condition of the refrigerator, and in this case, the lubrication may not be properly performed, thereby causing the abrasion of the piston430. In the present disclosure, a minimum refrigerant recovery operation time period determined as a minimum value of the operation time period of the compressor100may be set to ensure that a sufficient amount of refrigerant flows into the compressor100. In this case, the minimum refrigerant recovery operation time period may be set based on the operation state of the compressor (i.e., the driving input value).

Meanwhile, the minimum refrigerant recovery operation time period and the maximum refrigerant recovery operation time period may be set before the refrigerant recovery operation. In this case, S10may be omitted.

At S20, a driving input value of the compressor100detected at a first time point corresponding to a start time point (a beginning time point) of the refrigerant recovery operation is stored.

In this case, the first time point may be a start time point of the refrigerant recovery operation or may be a time point closer to the start time point of the refrigerant recovery operation. In addition, the driving input value may correspond to a driving power value applied to the compressor100. The driving input value (i.e., the first driving input value) at the first time point may be stored in a memory of the compressor controller.

At S30, a driving input value of the compressor100detected at a current time point of the refrigerant recovery operation is stored. The driving input value (i.e., a second driving input value) of the compressor100at the current time point may also be stored in the memory of the compressor controller.

At S40, the compressor controller determines whether abnormal operation has occurred in the compressor100.

The abnormal operation is a predefined operation of the compressor100and is related to protection logic of the compressor. For example, the abnormal operation may include a trip state of current, a low load state of the compressor, and the like.

If the compressor controller determines that the abnormal operation has occurred in the compressor100, the compressor controller determines whether a current operation time period of the refrigerant recovery is equal to or greater than a minimum operation time period at S50. Based on the current operation time period of the refrigerant recovery being less than the minimum operation time period, S50is performed again, and based on the current operation time period of the refrigerant recovery being equal to or greater than the minimum operation time period, the refrigerant recovery operation is terminated.

That is, at S50, the compressor100is driven for a time period that is longer than the minimum operation time period even if the abnormal operation occurs in the compressor100. That is, the S50is performed to introduce certain amount or more of refrigerant into the compressor100, thereby preventing the abrasion of the piston430due to lack of lubricant.

By contrast, based on determination that the abnormal operation does not occur in the compressor100, the compressor controller determines whether the current operation time period of the refrigerant recovery is equal to or greater than the minimum operation time period at S60.

Based on the current refrigerant recovery operation time period being less than the minimum operation time period, the process returns back to S30. That is, based on the current operation time of the refrigerant recovery not reaching the minimum operation time period, the refrigerant recovery operation is maintained and the current driving input value is updated. Accordingly, as described above, the refrigerant recovery operation is performed for a minimum time period or longer and the abrasion of the piston430may be prevented.

In addition, based on the current operation time period of the refrigerant recovery being equal to or longer than the minimum operation time period, the compressor controller determines whether a first ratio, which is a ratio between the driving input value at the first time point and the driving input value at the current time point is equal to or less than a threshold ratio at S70. That is, at S70, an end time point of the refrigerant recovery operation is determined by comparing the driving input value at the first time point with the driving input value at the current time point.

The threshold ratio is the above-mentioned preset ratio and may be determined experimentally. For example, the threshold ratio may be “0.5”.

Based on the first ratio being less than the threshold ratio, the compressor controller stops the driving of the compressor100and terminates the refrigerant recovery operation.

That is, the compressor controller determines the second time point of the refrigerant recovery operation at which the driving input value at the current time point is less than the driving input value at the first time point by the threshold value as the end time point of the refrigerant recovery operation. For example, the compressor controller may stop the driving of the compressor100and terminate the refrigerant recovery operation at the second time point when a ratio (a1/a2) between the driving power value (a1) at the first time point and the driving power value (a2) at the current time point is lower than the threshold ratio. In this case, the second time point may be an initial time point of the refrigerant recovery operation at which the first ratio is lower than the preset ratio.

As mentioned above, the driving power value detected based on the driving current and the driving voltage applied to the compressor100during the refrigerant recovery operation is closely related to the temperature/pressure of the suction end and the discharge end of the compressor100. That is, when the refrigerant recovery operation starts and the refrigerant is almost suctioned into the refrigerating room evaporator122and the freezing room evaporator124, a difference in temperature/pressure between the suction end and the discharge end is reduced and the driving power value applied to the compressor100is reduced.

During the refrigerant recovery operation, when the driving power value at the current time point (i.e., the driving input value) is greater than a value obtained by multiplying the driving power value at the first time point by the threshold ratio, the compressor controller determines that a large amount of refrigerant still remains inside the refrigerating room evaporator122and the freezing room evaporator124and does not terminate the refrigerant recovery operation. In addition, during the refrigerant recovery operation, when the driving power value at the current time point (that is, the driving input value) reaches a value obtained by multiplying the driving power value at the first time point by the threshold ratio, the compressor controller determines that the refrigerant is almost discharged from the inside of each of the refrigerating room evaporator122and the freezing room evaporator124and terminates the refrigerant recovery operation.

Based on the first ratio exceeding the threshold ratio, the compressor controller determines whether the current operation time period of refrigerant recovery is equal to or greater than a maximum operation time period at S80.

Based on the current operation time period of the refrigerant recovery being less than the maximum operation time period, the process returns back to S30. That is, based on the current operation time period of the refrigerant recovery not reaching the maximum operation time period, the refrigerant recovery operation is maintained and the current driving input value is updated.

In addition, based on the current operation time period of the refrigerant recovery being equal to or greater than the maximum operation time period, the refrigerant recovery operation is terminated.

Meanwhile, the method for controlling the refrigerator described with respect toFIG.13may be applied when the compressor100performs continuous operation and intermittent operation.

In short, the refrigerator according to an exemplary embodiment of the present disclosure may accurately determine the end time point of the refrigerant recovery operation based on the operation information of the compressor100, particularly, the driving input value of the compressor100. Specifically, the refrigerator according to an embodiment of the present disclosure may not perform the refrigerant recovery operation during a fixed operation time period, but may change the execution time period of the refrigerant recovery operation depending on the driving input value of the compressor100. Therefore, the end time point of the refrigerant recovery operation of the refrigerator may be determined simply and accurately.

In particular, the refrigerator according to an embodiment of the present disclosure may accurately determine the end time point of the refrigerant recovery operation without attaching the temperature sensor to the discharge end and the suction end of the compressor100. Therefore, manufacturing cost of the refrigerator may be reduced.

In addition, the refrigerator may be internally protected by accurately determining the end time point of the refrigerant recovery operation. Specifically, when the refrigerant recovery operation is performed for the fixed time period using the refrigerant gas as the lubricant for the piston, the refrigerant recovery operation may be terminated when the refrigerant gas is not sufficiently returned to the compressor according to the operation condition of the refrigerator. That is, when the sufficient amount of refrigerant gas that may be used as the lubricant for the piston is not present in the compressor, the abrasion of the piston may occur. In order to address the above problems, the refrigerator according to the present disclosure detects the driving input value or the driving power value input to drive the compressor to check whether sufficient amount of refrigerant gas has been introduced into the compressor, and when the refrigerant gas is sufficiently recovered, the refrigerant recovery operation is terminated by determining a time point at which the driving input value of the compressor is decreased. In addition, the refrigerator according to the present disclosure may accurately determine the end time point of the refrigerant recovery operation, thereby preventing unnecessary driving of the compressor and reducing unnecessary power consumption.

In addition, the refrigerator according to an embodiment of the present disclosure may ensure an optimum refrigerant recovery performance even with all cooling powers of the refrigerator and optimally supply the refrigerant to the evaporators122and124even under all operation conditions of the refrigerator, thereby increasing the operation efficiency of the refrigerator.

In addition, according to an embodiment of the present disclosure, the refrigerator may detect the operation state of the compressor100, and when the abnormal operation occurs in the compressor100, the refrigerator may terminate the refrigerant recovery operation and may be internally protected.

In addition, embodiments of the present disclosure may be implemented in the form of program instructions that may be executed via various computer means and may be recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like alone or in combination.

As described above, the present disclosure has been described with reference to embodiments and drawings limiting specific matters such as specific components. However, these are provided to aid overall understanding of the present disclosure and the present disclosure is not limited to the above embodiments and various modifications and changes can be made from the above description by a person having ordinary knowledge in the art to which the present disclosure pertains. Therefore, the spirit of the present disclosure should not be limited to the above embodiments and claims described below and all configurations that are equivalent to the claims or equivalent variations thereof belong to the scope of the spirit of the present disclosure.