KR100783239B1 - Controlling apparatus and its method for linear compressor - Google Patents

Abstract

A device and a method for controlling a linear compressor are provided to carry out control operation for a piston toward a top dead of a stroke by an inverter and inertia operation for the piston toward a bottom dead by a spring and the own mass of the piston, thereby reducing power consumption of the linear motor. A device for controlling a linear compressor includes a rectifying part(40) for rectifying commercial AC power, an inverter part(50) for receiving DC power from the rectifying part and applying an AC voltage to a linear motor(10), and a control part such as a microcomputer(70) for controlling a piston to carry out rectilinear reciprocation motion. The control part controls the inverter part in such a manner that the inverter part applies the AC voltage to the linear motor when the piston is positioned between a middle and a top dead center of a stroke to carry out control operation and blocks the AC voltage when the piston is positioned between the middle and a bottom dead center of the stroke to carry out inertia operation.

Description

CONTROLLING APPARATUS AND ITS METHOD FOR LINEAR COMPRESSOR}

1 is a configuration diagram of a driving apparatus of a linear compressor according to the prior art.

2A and 2B are graphs of a control signal and an input voltage in the driving device of FIG. 1.

3 is a cross-sectional view of a linear compressor according to the present invention.

4 is a configuration diagram of a driving device of the linear compressor according to the present invention.

5A to 5C are operation graphs on a control signal, an input voltage, and a stroke in the driving device of FIG. 4.

<Explanation of symbols for the main parts of the drawings>

6: piston 40: rectifier circuit

50: inverter circuit 60: detector

60: micom

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear compressor, and more particularly, to a driving apparatus and a driving method of a linear compressor for reducing power consumption by performing a control operation and an inertia operation of a piston in parallel.

In general, a compressor is a mechanical device that increases pressure by receiving power from a power generator such as an electric motor or a turbine to compress air, refrigerant, or various other working gases. It is widely used throughout.

These compressors are classified into a reciprocating compressor which compresses the refrigerant while linearly reciprocating the inside of the cylinder by forming a compression space in which the working gas is absorbed and discharged between the piston and the cylinder. And a rotary compressor for compressing the refrigerant while the roller is eccentrically rotated along the inner wall of the cylinder to form a compression space in which the working gas is sucked and discharged between the eccentrically rotating roller and the cylinder. As a scroll compressor that compresses the refrigerant while the rotating scroll rotates along the fixed scroll to form a compression space in which the working gas is absorbed and discharged between the orbiting scroll and the fixed scroll. Divided.

In general, a linear compressor sucks, compresses, and discharges a refrigerant by using a linear driving force of a motor. A compression unit including a cylinder and a piston for compressing a refrigerant gas is large, and a linear motor supplying driving force to the compression unit. It is divided into included driving parts.

Specifically, the linear compressor is installed so that the cylinder is fixed inside the sealed container, the piston is installed in the cylinder to reciprocate linear movement, the compression space in the cylinder as the piston reciprocating linear movement in the cylinder It is configured to compress and then discharge the refrigerant into the inlet, the inlet and outlet valve assembly is installed in the compression space to adjust the inflow and discharge of the refrigerant in accordance with the pressure in the compression space.

In addition, the linear motor for generating a linear motion force to the piston is installed so as to be connected to each other, the linear motor is provided with an inner stator and an outer stator configured to be laminated in a circumferential direction around the cylinder with a predetermined gap, A coil (or coil winding) is installed inside the inner stator or the outer stator, and a permanent magnet is installed in the gap between the inner stator and the outer stator so as to be connected to the piston.

At this time, the permanent magnet is installed to be movable in the direction of movement of the piston, the reciprocating linear movement in the direction of movement of the piston by the electromagnetic force generated as the current flows in the coil.

1 is a configuration diagram of a driving apparatus of a linear compressor according to the prior art. As shown in FIG. 1, the driving apparatus of the linear compressor includes a rectifier circuit 100 that receives a commercial AC power and provides a DC power or DC voltage, and receives the DC power or DC voltage from the microcomputer 400. Inverter circuit 200 that is switched by a control signal to apply an AC voltage to the motor M, the sensing unit 300 for detecting the state of the motor (M) or load, and the motor detected from the sensing unit 300 (M) or the microcomputer 400 for controlling the cooling power by generating and applying a control signal to the inverter circuit 200 in accordance with the state of the load.

The rectifier circuit 100 includes a diode bridge (not shown), a capacitor (not shown), and the like to perform rectification and smoothing functions.

When the inverter circuit 200 is a single phase power source, as shown in FIG. 1, the inverter circuit 200 includes four switching elements Q1 to Q4, and each switching element Q1 to Q4 is controlled by a control signal from the microcomputer 400. As the on / off is turned on, the input DC voltage is converted into an AC voltage and applied to the motor M.

The sensing unit 300 includes elements such as a current sensor, a voltage sensor, a temperature sensor, and the like, such as a state of the motor M (for example, a compression stroke or an expansion stroke) and a state of a load (for example, an overload, A low load, a heavy load, etc.) is applied to the microcomputer 400 to detect the detection signal.

The microcomputer 400 generates a control signal to the inverter circuit 200 according to the detection signal received from the sensing unit 300, and by this control signal, the motor M may generate an appropriate cooling force according to the load state. have. Such control signals are described in detail in FIGS. 2A and 2B below.

2A and 2B are graphs of a control signal and an input voltage in the driving device of FIG. 1.

As shown in FIG. 2A, when the microcomputer 400 performs the compression stroke of the linear compressor during the half cycle (0 to T / 2), that is, the piston proceeds in the direction of the top dead center (TDC). To do this, the control signal shown in FIG. 2A is applied to the inverter circuit 200. That is, by applying control signals to the switching elements Q1 and Q4 of the inverter circuit 200, the switching elements Q1 and Q4 are turned on, and the switching elements Q2 and Q3 are turned off.

During the next half cycle (T / 2 to T), when performing the expansion stroke of the linear compressor, i.e., for the piston to proceed in the direction of the bottom dead center (BDC), shown in FIG. 2A with the inverter circuit 200. The applied control signal. That is, by applying control signals to the switching elements Q2 and Q3 of the inverter circuit 200, the switching elements Q2 and Q3 are turned on, and the switching elements Q1 and Q4 are turned off.

That is, the microcomputer 400 applies the control signal to the inverter circuit 200 in the TDC section to perform the control operation, and applies the control signal to the inverter circuit 200 in the BDC section to perform the control operation. Perform control operation on the piston.

2B illustrates waveforms of input voltages applied to the motor M by the control of the inverter circuit 200 of the microcomputer 400. As shown, the input voltage for half cycle (0 to T / 2) and the input voltage for the next half cycle (T / 2 to T) are both generated by the control signal by the microcomputer (400).

In general, in the linear compressor, the microcomputer 400 requires precise control of the piston in the TDC section, but substantially no control of the piston in the BDC section is required. Nevertheless, the driving apparatus according to the prior art is to perform a control operation in the entire section, there is a problem of continuously consuming power.

In order to solve this problem, it is an object of the present invention to provide a driving apparatus and a driving method of a linear compressor that performs only control of the movement in the top dead center direction of the piston.

In addition, an object of the present invention is to provide a driving apparatus and a driving method of a linear compressor which performs a control operation by an inverter circuit and an inertial operation by the mass of a spring and a piston.

The driving apparatus of the linear compressor of the present invention is to rectify the commercial AC power source, the inverter unit for applying an AC voltage to the linear motor by receiving the DC power of the rectifying unit, and the piston of the linear compressor to perform a linear reciprocating motion, And a control unit for controlling the inverter unit to perform application and interruption of the AC voltage to the linear motor, respectively, corresponding to the case where the piston is between the center point and the top dead center of the stroke and between the center point and the bottom dead center. Therefore, the control operation and the inertia operation of the piston are performed according to the position of the piston.
In addition, the driving apparatus of the linear compressor of the present invention includes a rectifying unit for rectifying commercial AC power, an inverter unit for applying an AC voltage to the linear motor by receiving the DC power of the rectifying unit, and a piston of the linear compressor to perform a linear reciprocating motion. However, in response to the compression stroke and the expansion stroke of the linear compressor, respectively, the control unit for controlling the inverter unit to perform the application and blocking of the AC voltage to the linear motor, the control of the piston according to the stroke performed by the linear compressor Allow operation and inertial operation to be performed.
In addition, the linear compressor driving method of the linear reciprocating motion in the closed space of the present invention, when the piston is between the center point and the top dead center of the stroke, the control operation of the piston, the piston and the center point of the stroke If it is between the bottom dead center, including the step of inertial operation of the piston, so that the control operation and the inertia operation of the piston is performed according to the position of the piston.

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In the following, the invention is explained in detail on the basis of the embodiments of the invention and the accompanying drawings. However, the scope of the present invention is not limited by the following embodiments and drawings, and the scope of the present invention will be limited only by the contents described in the claims below.

3 is a cross-sectional view of a linear compressor according to the present invention.

In the linear compressor according to the present invention, as shown in FIG. 3, an inlet tube 2a and an outlet tube 2b through which refrigerant flows in and out are installed at one side of the sealed container 2, and a cylinder is formed inside the sealed container 2. (4) is fixed so that the piston (6) is installed inside the cylinder (4) to reciprocate linear movement to compress the refrigerant sucked into the compression space (P) inside the cylinder (4) Various springs are installed to elastically support in the direction of movement of 6), and the piston 6 is installed to be connected to the linear motor 10 for generating a linear reciprocating drive force.

In addition, a suction valve 22 is installed at one end of the piston 6 in contact with the compression space P, and a discharge valve assembly 24 is installed at one end of the cylinder 4 in contact with the compression space P. The suction valve 22 and the discharge valve assembly 24 are automatically adjusted to open and close according to the pressure in the compression space P, respectively.

Here, the airtight container 2 is installed so that the upper and lower shells are coupled to each other so that the inside is sealed, and an inlet tube 2a through which refrigerant is introduced and an outlet tube 2b through which the refrigerant is discharged are installed, and a cylinder ( 4) Inside the piston 6 is elastically supported in the movement direction to enable the reciprocating linear motion, and the linear motor 10 is assembled to each other by the frame 18 outside the cylinder 4 to constitute an assembly, The assembly is installed to be elastically supported by the support spring 29 on the inner bottom surface of the sealed container (2).

In addition, a predetermined oil is contained in the bottom surface of the airtight container (2), and an oil supply device (30) for pumping oil is installed at the bottom of the assembly, and oil is provided in the lower frame (18) of the assembly. An oil supply pipe 18a is formed to be supplied between the cylinders 4, so that the oil supply device 30 is operated by the vibration generated by the reciprocating linear movement of the piston 6 to pump oil, and The oil is supplied into the gap between the piston 6 and the cylinder 4 along the oil supply pipe 18a to cool and lubricate.

Next, the cylinder 4 is formed in a hollow shape so that the piston 6 can reciprocate linearly, and a compression space P is formed at one side, and one end is located close to the inside of the inflow pipe 2a. It is preferable to be provided on the same straight line as the inflow pipe 2a.

Of course, the cylinder (4) is installed in one end close to the inlet pipe (2a) so that the reciprocating linear movement of the piston 6, the discharge valve assembly 24 is provided at one end on the opposite side to the inlet pipe (2a) Is installed.

At this time, the discharge valve assembly 24 is a discharge cover (24a) is provided to form a predetermined discharge space on one end side of the cylinder 4, and the discharge valve is installed to open and close one end of the compression space (P) side of the cylinder ( 24b) and a valve spring 24c, which is a kind of coil spring that imparts an elastic force in the axial direction between the discharge cover 24a and the discharge valve 24b, and has an O-ring R around one end of the cylinder 4; It is installed so that the discharge valve 24a is in close contact with one end of the cylinder (4).

In addition, between the one side of the discharge cover (24a) and the outlet pipe (2b) is connected to the loop pipe 28 is formed bent, the loop pipe 28 not only guides the compressed refrigerant to be discharged to the outside The vibration caused by the interaction of the cylinder 4, the piston 6, and the linear motor 10 buffers the transmission of the entire sealed container 2.

Therefore, when the pressure of the compression space P becomes equal to or greater than a predetermined discharge pressure as the piston 6 reciprocates linearly inside the cylinder 4, the valve spring 24c is compressed to open the discharge valve 24b. The refrigerant is discharged from the compressed space P, and then completely discharged along the loop pipe 28 and the outlet pipe 2b.

Next, the piston 6 has a coolant flow path 6a formed at the center so that the coolant flowing from the inlet pipe 2a flows, and one end of the piston 6 adjacent to the inlet pipe 2a is connected by a linear motor. The suction valve 22 is installed at one end of the opposite side to the inflow pipe 2a and is installed to be directly connected to the inlet pipe 2a, and is installed to be elastically supported by various springs in the movement direction of the piston 6.

At this time, the suction valve 22 is formed in a thin plate shape so that the center portion is partially cut to open and close the refrigerant passage 6a of the piston 6, and one side is fixed by a screw to one end of the piston 6a. It is installed as possible.

Therefore, when the pressure of the compression space P becomes below the predetermined suction pressure lower than the discharge pressure as the piston 6 reciprocates linearly inside the cylinder 4, the suction valve 22 is opened to compress the refrigerant. When the suction in the space P and the pressure in the compression space P becomes equal to or greater than a predetermined suction pressure, the refrigerant in the compression space P is compressed in the state where the suction valve 22 is closed.

In particular, the piston 6 is installed so as to be elastically supported in the movement direction. Specifically, a piston flange 6b protruding in a radial direction at one end of the piston 6 proximate to the inflow pipe 2a includes a mechanical spring such as a coil spring or the like. 8a, 8b is elastically supported in the movement direction of the piston 6, the refrigerant contained in the compression space (P) on the opposite side to the inlet pipe (2a) acts as a gas spring by its elastic force to the piston (6) It will elastically support.

4 is a configuration diagram of a driving device of the linear compressor according to the present invention.

The driving apparatus of the linear compressor is a rectifier circuit 40 which is supplied with a commercial AC power supply to provide a DC power source or a DC voltage, and is switched by a control signal from the microcomputer 70 when the DC power source or DC voltage is applied to switch the AC voltage. To the linear motor (M) 10, the inverter circuit 50, the detection unit 60 for detecting the state of the linear motor (M) or load, and the linear motor (M) detected from the detection unit 60 Or a microcomputer 70 for generating and applying a control signal to the inverter circuit 50 according to the state of the load to control the cooling power.

The rectifier circuit 40 includes a diode bridge (not shown), a capacitor (not shown), and the like to perform rectification and smoothing functions.

When the inverter circuit 50 is a single phase power source, as shown in FIG. 4, the inverter circuit 50 includes four switching elements Q1 to Q4, and each switching element Q1 to Q4 is controlled by a control signal from the microcomputer 70. As the on / off is turned on, the input DC voltage is converted into an AC voltage having a predetermined operating frequency and applied to the linear motor M. FIG.

The sensing unit 60 includes elements such as a current sensor, a voltage sensor, a temperature sensor, and the like, such as a state of the linear motor M (for example, a compression stroke or an expansion stroke) and a state of a load (for example, an overload). , A low load, a heavy load, etc.) is applied to the microcomputer 70.

The microcomputer 70 generates a control signal to the inverter circuit 50 according to the detection signal received from the sensing unit 60, and the linear motor M generates an appropriate cooling force according to the load state. Can be. Such control signals are described in detail in FIGS. 5A to 5C below.

5A to 5C are operation graphs on a control signal, an input voltage, and a stroke in the driving device of FIG. 4.

As shown in FIG. 5A, the microcomputer 70 performs the compression stroke of the linear compressor during the half cycle (0 to T / 2) (when the piston 6 is between the top dead center and the center point of the stroke), that is, In order to control the piston 6 to proceed in the top dead center (TDC) direction, the control signal shown in FIG. 5A is applied to the inverter circuit 50. That is, by applying control signals to the switching elements Q1 and Q4 of the inverter circuit 50, the switching elements Q1 and Q4 are turned on, and the switching elements Q2 and Q3 are turned off.

During the next half cycle (T / 2 to T), when performing the expansion stroke of the linear compressor (when the piston 6 is between the center and bottom dead center of the stroke), ie the piston is the bottom dead center (BDC). In order to proceed in the direction, no control signal is applied to the inverter circuit 50. That is, all the switching elements Q1 to Q4 of the inverter circuit 50 are turned off. At this time, the piston 6 is moved to the bottom dead center (BDC) direction automatically by the force to return to the original state by the spring element composed of the gas spring by the refrigerant in the cylinder 4, and the mechanical spring (8a, 8b). do.

That is, the microcomputer 70 performs a control operation by applying a control signal to the inverter circuit 50 in the TDC section (section between the center point M of the stroke and the top dead center (TDC)), and performs the control operation in the BDC section (center point of the stroke). (M) and the bottom dead center (BDC)) does not apply any control signal to the inverter circuit 50 to perform the inertial operation. This inertial motion depends on the natural frequency according to the mass of the spring element and the piston 6.

5B shows waveforms of input voltages applied to the linear motor M by the control of the inverter circuit 50 of the microcomputer 70. As shown, the input voltage during the half cycle (0 to T / 2) is an alternating voltage applied by the inverter circuit 50, and then the input voltage during the half cycle (T / 2 to T) is determined by the piston (6). This indicates the counter electromotive voltage caused by inertia operation, and does not use any electric energy applied through the rectifier circuit 40 due to this counter electromotive voltage.

FIG. 5C illustrates a stroke in which the piston 6 linearly reciprocates, and a control operation by the microcomputer 70 is performed with respect to the top dead center (TDC) direction in the TDC section, and the bottom dead center (BDC) in the BDC section. With respect to the direction, it indicates that the inertial operation by the mass of the spring element and the piston 6 is performed.

The present invention of such a configuration has the effect of driving the linear compressor through a simple control that performs only the control for the movement in the top dead center direction of the piston.

In addition, the present invention has the effect of reducing the power consumed by the linear compressor to perform the control operation by the inverter circuit and the inertial operation by the mass of the spring and the piston in parallel.

Claims (8)

Rectifying unit for rectifying the commercial AC power supply; An inverter unit receiving the DC power from the rectifying unit and applying an AC voltage to the linear motor; The piston of the linear compressor is configured to perform a linear reciprocating motion, in response to the case where the piston is between the center point and the top dead center of the stroke and between the center point and the bottom dead center, respectively, to apply and cut off the AC voltage to the linear motor. The driving apparatus of the linear compressor, characterized in that consisting of a control unit for controlling the inverter unit to perform each. The linear compressor driving apparatus of claim 1, wherein when the piston is between a center point and a top dead center of the stroke, the control unit applies a control signal to the inverter unit so that an AC voltage is applied to the linear motor. 2. A drive system for a linear compressor according to claim 1, wherein the piston is inertial when the piston is between a center point and a bottom dead center of the stroke. Rectifying unit for rectifying the commercial AC power supply; An inverter unit receiving the DC power from the rectifying unit and applying an AC voltage to the linear motor; Wherein the piston of the linear compressor to perform a linear reciprocating movement, in response to the compression stroke and the expansion stroke of the linear compressor, respectively, the control unit for controlling the inverter unit to perform the application and blocking of the AC voltage to the linear motor A drive device for a linear compressor. 5. The driving apparatus of claim 4, wherein, during the compression stroke of the linear compressor, the control unit applies a control signal to the inverter unit so that an AC voltage is applied to the linear motor. 5. A drive system for a linear compressor according to claim 4, wherein said piston is inertial during the expansion stroke of said linear compressor. In a linear compressor driving method for linearly reciprocating a piston in a closed space, If the piston is between a center point and a top dead center of the stroke, controlling the piston for driving; And when the piston is between the center point and the bottom dead center of the stroke, inertial operation of the piston. The linear compressor driving method according to claim 7, wherein the control operation step controls the piston in a top dead center direction.

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