WO-2026095112-A1 - CONTROL DEVICE FOR LINEAR COMPRESSOR

WO2026095112A1WO 2026095112 A1WO2026095112 A1WO 2026095112A1WO-2026095112-A1

Abstract

A control device for a linear compressor, according to one aspect of the present disclosure, comprises: an inverter unit that supplies an alternating voltage to the linear compressor on the basis of a control signal; and a control unit that supplies the control signal to the inverter unit so as to control reciprocating motion of a piston, wherein the control unit performs control such that a first alternating voltage having a first amplitude is supplied to a motor in a first cycle, and a second alternating voltage having a second amplitude smaller than the first amplitude is supplied to the motor in a second cycle.

Inventors

PARK, SUNGHO
CHOI, JONGYOON
Heo, Jungwan
WOO, Donghun

Assignees

엘지전자 주식회사

Dates

Publication Date: 20260507
Application Date: 20241030

Claims (20)

In a control device for a linear compressor including a piston and a motor, An inverter unit that supplies AC voltage to the linear compressor based on a control signal; and, A control unit that controls the reciprocating motion of the piston by supplying the control signal to the inverter unit; The above control unit is, In the first cycle, a first alternating current voltage having a first amplitude is supplied to the motor, and A control device for a linear compressor that controls the supply of a second alternating current voltage having a second amplitude smaller than the first amplitude to the motor in the second cycle.
In paragraph 1, The above control unit is, In the first operating mode, the linear compressor is controlled by the first cycle and the second cycle, and A control device for a linear compressor that controls the linear compressor only by the first cycle in a second operating mode where the load is greater than in the first operating mode.
In paragraph 1, A control device for a linear compressor in which the first cycle and the second cycle are performed alternately.
In paragraph 1, When the above first cycle is performed once, A control device for a linear compressor in which the above second cycle is performed two or more times.
In paragraph 1, A control device for a linear compressor in which the amplitude of the first alternating current voltage is 60% or less of the amplitude of the second alternating current voltage.
In paragraph 1, A control device for a linear compressor in which the operating frequency of the first cycle is different from the operating frequency of the second cycle.
In paragraph 1, The above control unit is, A control device for a linear compressor that controls both the first cycle and the second cycle so that the stroke is smaller than the maximum value.
In paragraph 1, A phase difference detection unit for detecting a phase difference between the motor current applied to the motor and the stroke; and, A control device for a linear compressor further comprising: a power calculation unit that calculates load power based on the motor voltage applied to the motor and the motor current applied to the motor.
In paragraph 8, A voltage detection unit for detecting the motor voltage applied to the above motor; A current detection unit for detecting a motor current applied to the above motor; and A control device for a linear compressor further comprising a stroke calculation unit that calculates the stroke based on the motor voltage and the motor current.
In Paragraph 9, A control device for a linear compressor further comprising a gas spring calculation unit that calculates a gas spring constant based on the motor current, the stroke, and the phase difference.
A control device for a linear compressor comprising a motor, a cylinder, a piston disposed inside the cylinder, a discharge valve disposed at one end of the cylinder, and a suction valve disposed at one end of the piston, An inverter unit that supplies AC voltage to the linear compressor based on a control signal; and, A control unit that controls the reciprocating motion of the piston by supplying the control signal to the inverter unit; The above control unit is, In the first cycle, the suction valve and the discharge valve are opened, and A control device for a linear compressor that controls the suction valve to be open and the discharge valve not to be open during the second cycle.
In Paragraph 11, The above control unit is, In the first operating mode, the discharge valve is controlled to open once every two cycles, and A control device for a linear compressor that controls the discharge valve to open once per cycle in a second operating mode, where the load is greater than in the first operating mode.
In Paragraph 11, A control device for a linear compressor in which the first cycle and the second cycle are performed alternately.
In Paragraph 11, When the above first cycle is performed once, A control device for a linear compressor in which the above second cycle is performed two or more times.
In Paragraph 11, A control device for a linear compressor in which the amplitude of the voltage supplied to the motor in the first cycle is 60% or less of the amplitude of the voltage supplied to the motor in the second cycle.
In Paragraph 11, A control device for a linear compressor in which the operating frequency of the first cycle is different from the operating frequency of the second cycle.
In Paragraph 11, The above control unit is, A control device for a linear compressor that controls both the first cycle and the second cycle so that the stroke is smaller than the maximum value.
In Paragraph 11, A phase difference detection unit for detecting a phase difference between the motor current applied to the motor and the stroke; and, A control device for a linear compressor further comprising: a power calculation unit that calculates load power based on the motor voltage applied to the motor and the motor current applied to the motor.
In Paragraph 18, A voltage detection unit for detecting the motor voltage applied to the above motor; A current detection unit for detecting a motor current applied to the above motor; and A control device for a linear compressor further comprising a stroke calculation unit that calculates the stroke based on the motor voltage and the motor current.
In Paragraph 19, A control device for a linear compressor further comprising a gas spring calculation unit that calculates a gas spring constant based on the motor current, the stroke, and the phase difference.

Description

Control device for a linear compressor The present disclosure relates to a compressor control device, and more specifically, to a control device for a linear compressor capable of efficiently controlling a linear compressor. A compressor is generally a device that increases pressure by compressing refrigerants or various other working gases, and is widely used in refrigeration equipment, such as refrigerators and air conditioners. Compressors are broadly classified into reciprocating compressors, rotary compressors, and scroll compressors. In a reciprocating compressor, a compression space is formed between the piston and the cylinder where the working gas is drawn in and discharged, and the piston compresses the refrigerant as it moves in a straight line back and forth inside the cylinder. In a rotary compressor, a compression space is formed between an eccentrically rotating roller and a cylinder where working gas is drawn in and discharged, and the roller compresses the refrigerant as it rotates eccentrically along the inner wall of the cylinder. In a scroll compressor, a compression space is formed between an orbiting scroll and a fixed scroll where working gas is drawn in and discharged, and the orbiting scroll compresses the refrigerant as it rotates along the fixed scroll. Among them, reciprocating compressors can be classified into reciprocal type (reciprocal compressor) and linear type (linear compressor) depending on the method of driving the piston. Specifically, the reciprocating method converts the rotational force of a rotary motor into linear reciprocating motion by connecting a crankshaft to the crankshaft and a piston to the crankshaft, whereas the linear method directly connects a piston to the actuator of a linear motor to cause the piston to reciprocate using the motor's linear motion. Such reciprocating compressors consist of an electric unit that generates driving force and a compression unit that receives driving force from the electric unit and compresses the fluid. Motors are generally used as the electric unit, and in the case of the aforementioned linear type, a linear motor is used. When the above reciprocating compressor is used in a refrigerator or air conditioner, the voltage input to the reciprocating compressor is varied to vary the compression ratio of the reciprocating compressor, and accordingly, the freezing capacity can be controlled. As mentioned above, linear reciprocating compressors have lower friction losses because they lack a crankshaft that converts rotational motion into linear motion, so they have higher compression efficiency than reciprocating compressors. Meanwhile, the reciprocating compressor for the refrigerator controls the operating frequency, and the linear compressor controls the stroke size to implement variable cooling power. Linear compressors control the size of the piston stroke according to the load to ensure efficient operation through appropriate variable cooling power. Prior Art 1 (Korean Published Patent Application No. 10-2010-0104952) does not detect TDC under general load conditions where full stroke control is not required, detects a characteristic point where the phase difference (or gas spring constant) between the motor current and the stroke numerically matches the load power according to the compressor load, drives the motor by supplying input power corresponding to the detected characteristic point, and thereby reduces power consumption by changing the cooling power accordingly. Meanwhile, the aforementioned TDC is an abbreviation for "Top Dead Center," which is the English notation for the piston's top dead center in a linear compressor; physically, it refers to the stroke at the completion of the piston's compression stroke. Similarly, Bottom Dead Center (BDC) is an abbreviation for "Bottom Dead Center" and physically refers to the stroke at the completion of the piston's intake stroke. Prior art document 2 (Korean Published Patent Application No. 10-2015-0072167) designs the initial value of the piston based on the normal operating range and increases the maximum cooling power by adding DC current to the motor current in the high-load operating range to increase the initial value of the piston. However, in the low-load operating range, efficiency may decrease as friction losses and re-expansion losses increase. FIG. 1 is a perspective view of a refrigerator including a linear compressor according to one embodiment of the present disclosure. FIG. 2 is a cross-sectional view of a linear compressor according to one embodiment of the present disclosure. FIG. 3 is an internal block diagram of a control device for a linear compressor according to one embodiment of the present disclosure. FIG. 4 is an internal block diagram of a control device for a linear compressor according to one embodiment of the present disclosure. FIGS. 5 and FIGS. 6 are drawings referenced in the description of parameter calculation according to an embodiment