Control device of compressor, compressor, and control method of compressor

Abstract

The present application relates to a compressor control device, a compressor, and a compressor control method, which generates a control signal by compensating for a duty ratio of the control signal to be different in each of an interval in which a compression stroke is performed by the compressor and an interval in which a suction stroke is performed.

Description

TECHNICAL FIELD

[0001] The present application relates to a compressor control device, a compressor, and a compressor control method related to operation control of a compressor. BACKGROUND

[0002] The background art of the present application relates to control of a compressor, and more particularly, to control of an operation region of a reciprocating compressor used in a refrigerator.

[0003] In the operation characteristics of a refrigerator, it is necessary to improve the operation rate to improve power consumption and perform constant temperature operation. In particular, in the actual load (RT 16℃) operation characteristics under the strengthening of energy regulations, intermittent operation is performed in parallel due to a low operation rate, and thus it is necessary to expand the low speed operation region due to deterioration of power consumption, however, as the rotation speed decreases, problems of a decrease in compression efficiency and generation of vibration occur. This is because, as the operation speed decreases, the rotational energy is greatly reduced, and thus vibration is induced due to a difference in speed between a compression interval and a suction interval corresponding to a load, and a decrease in compression efficiency is induced due to an increase in the use current required to correspond to the load.

[0004] On the other hand, in the related art, a method of accelerating the speed of a compression stroke and reducing vibration by compensating for current before the top dead center of a piston (or in a maximum compression load interval) has been proposed, however, in this related art, as the use current increases, input is inevitably increased, and thus there is a problem of a decrease in efficiency of compression.

[0005] As a result, in the related art, a technology capable of simultaneously improving the problems of vibration and efficiency has not been proposed, and thus there is a problem that operation in a low speed region is limited. SUMMARY

[0006] The present application aims to improve the problems in the related art as described above.

[0007] That is, the present application provides an embodiment of a compressor control device, a compressor, and a compressor control method capable of improving the problems in the related art as described above.

[0008] Specifically, an embodiment of a compressor control device, a compressor, and a compressor control method capable of improving the problems of an increase in vibration and a decrease in efficiency by appropriate compensation per stroke interval is provided.

[0009] In particular, an embodiment of a compressor control device, a compressor, and a compressor control method capable of improving efficiency while suppressing vibration generated in a low speed operation region is provided.

[0010] Also, provided is an embodiment of a control device of a compressor, a compressor, and a control method of a compressor capable of reducing power consumption by expanding an operation region and increasing an operation rate in a reciprocating compressor used in a refrigerator.

[0011] An embodiment of the present specification for solving the problem as described above will generate the control signal by compensating the duty ratio of the control signal for each of the interval of performing the compression stroke and the interval of performing the suction stroke differently as a means for solving the technical problem.

[0012] For example, it is characterized by generating the control signal by compensating the duty ratio of the control signal according to a first compensation reference when the compressor performs the compression stroke, and compensating the duty ratio of the control signal according to a second compensation reference when performing the suction stroke.

[0013] Alternatively, it is characterized by generating the control signal by compensating the duty ratio of the control signal according to a preset first compensation reference during the period in which the compressor compresses air, and compensating the duty ratio of the control signal according to a preset second compensation reference during the period in which the compressor discharges the compressed air.

[0014] Alternatively, it is characterized by generating the control signal by compensating the duty ratio of the control signal according to a preset first compensation reference during the period from the time point at which the piston of the compressor is located at the bottom dead center to the time point at which the valve of the cylinder is opened, and compensating the duty ratio of the control signal according to a preset second compensation reference during the period from the time point at which the valve is closed to the period in which the internal pressure of the cylinder decreases to a constant size.

[0015] Alternatively, it is characterized by controlling the operation of the compressor by dividing a plurality of stroke intervals according to the change in the internal pressure, and changing the compensation of the current applied to the motor according to the plurality of stroke intervals.

[0016] On the other hand, it is characterized in that, in the case of discriminating the stroke interval of the compressor and controlling, the operation of the compressor is controlled by judging the current stroke interval based on the operation state of the compressor, and compensating the compensation value corresponding to the current operation interval.

[0017] In particular, it is characterized in that, when the compressor operates at an operation frequency lower than a preset reference frequency, that is, when the compressor operates in a low speed region, the current compensation is changed at the time of the compression stroke and the suction stroke.

[0018] As described above, by changing the compensation at the time of the compression stroke and the suction stroke, the efficiency is improved while reducing the vibration in the low speed operation region, thereby solving the problem as described above.

[0019] The technical features described above can be implemented by applying one or more of a compressor control device that controls operation of a compressor, a system that controls a compressor, a compressor, a compressor system, a compressor control method, a method of controlling a compressor, a method of operating a compressor, a method of stroke execution of a compressor, and a compensation control method of a compressor, and the present specification provides embodiments of a compressor control device, a compressor, and a compressor control method that use the technical features described above as means for solving problems.

[0020] An embodiment of the compressor control device of the present specification that uses the technical features as means for solving problems is a control device of a compressor that controls operation of the compressor, and includes an inverter section that converts a power source input from an external power source into a drive power source for driving a motor of the compressor and applies the drive power source to the motor, and a control section that detects one or more of a magnitude of the drive power source, a position of a piston of the compressor, and an internal pressure of a cylinder in which the piston reciprocates, generates a control signal of pulse width modulation (PWM) for controlling switching operation of the inverter section based on a detection result, and controls the switching operation by applying the control signal to the inverter section, the control section generating the control signal by compensating a duty ratio of the control signal differently for each of an interval in which a compression stroke of the compressor is performed and an interval in which a suction stroke is performed.

[0021] An embodiment of the compressor of the present specification that uses the technical features as means for solving problems includes a piston that reciprocates by rotation of a motor, a cylinder in which the piston reciprocates, a valve that restricts air inflow and outflow of the cylinder, and a control device that controls operation of the compressor by controlling application of a drive power source applied to the motor according to one or more of a magnitude of the drive power source, a position of the piston, and an internal pressure of the cylinder, the control device controlling operation of the compressor by changing compensation of a current applied to the motor according to a plurality of stroke intervals divided according to a change in the internal pressure if an operation speed of the compressor is below a predetermined reference speed.

[0022] The embodiment of the compressor control method of the present specification, which is a compressor control method of a compressor control device of a compressor, in which the compressor control device includes an inverter section that converts a power source input from an external power source into a drive power source for driving a motor of the compressor and applies the drive power source to the motor, and a control section that generates a control signal for controlling a PWM (Pulse Width Modulation) of a switching operation of the inverter section and controls the switching operation by applying the control signal to the inverter section, the compressor control method of the compressor control device including: a step of comparing an operation speed of the compressor with a preset reference speed; a step of judging a stroke interval of the compressor based on one or more of a size of the drive power source, a position of a piston of the compressor, and an internal pressure of a cylinder in which the piston reciprocates, if the operation speed is below the reference speed; a step of compensating a control command, which is a basis for generation of the control signal, by a current compensation value corresponding to a current stroke interval, based on a compensation reference that is preset differently for the stroke intervals; and a step of generating the control signal from the control command and applying the control signal to the inverter section.

[0023] Further, another embodiment of the compressor control method of the present specification, which is a compressor control method of a compressor control device of a compressor, in which the compressor control device includes: an inverter section that converts a power source input from an external power source into a drive power source for driving a motor of the compressor and applies the drive power source to the motor; and a control section that detects one or more of a magnitude of the drive power source, a position of a piston of the compressor, and an internal pressure of a cylinder in which the piston reciprocates, generates a PWM (Pulse Width Modulation) control signal for controlling a switching operation of the inverter section based on a detection result, and controls the switching operation by applying the control signal to the inverter section, the compressor control method of the compressor control device including: a step of compensating a duty ratio of the control signal by a first-1 compensation value from a time point at which the piston is at a bottom dead center to a time point at which the piston moves to a specific position; a step of compensating the duty ratio by a first-2 compensation value that is larger than the first-1 compensation value from a time point at which the piston is at the specific position to a time point at which a valve of the cylinder is opened; a step of not compensating the duty ratio by a compensation value from a time point that is a constant time before a time point at which the piston is at a top dead center to a time point that is a constant time after the time point at which the piston is at the top dead center; a step of compensating the duty ratio by a second-1 compensation value from a time point that is the constant time after the time point at which the piston is at the top dead center to a time point at which discharge of air compressed in the cylinder ends; and a step of compensating the duty ratio by a second-2 compensation value that is smaller than the second-1 compensation value from a time point at which the discharge of the air compressed in the cylinder ends to a time point at which the piston is at the bottom dead center.

[0024] The compressor control device, the compressor, and the compressor control method of the embodiment can appropriately compensate by changing the compensation at the compression stroke time and the suction stroke time.

[0025] Thus, it is possible to reduce vibration while improving efficiency in the low-speed operation region.

[0026] Further, by improving efficiency while suppressing generation of vibration in the low-speed operation region, it is possible to improve applicability, stability, efficiency, and reliability in the low-speed operation region.

[0027] Thus, the operation region is expanded, and power consumption is reduced due to an increase in operation rate.

[0028] As a result, it is possible to not only improve problems in the related art but also improve the utility and the availability of a product group using the compressor. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1is a perspective view showing the outer shell of a reciprocating compressor as an example and showing the inside thereof.

[0030] Figure 2 is a sectional view showing the inside of the reciprocating compressor as shown in Figure 1 .

[0031] Figure 3 is a configuration diagram of a control device of the compressor of the embodiment.

[0032] Figure 4 is a specific example diagram of the control device of the compressor as shown in Figure 3 .

[0033] Figure 5 is an example for explaining an example of application of compensation by stroke interval of the embodiment Figure 1 .

[0034] Figure 6 is an example for explaining an example of application of compensation by stroke interval of the embodiment Figure 2 .

[0035] Figure 7 is a flowchart showing the operation control procedure of the compressor of the embodiment.

[0036] Figure 8 is a flow of the compressor control method of the embodiment Figure 1 .

[0037] Figure 9 is a flow of the compressor control method of the embodiment Figure 2 .

[0038] Figure 10A is an example diagram showing the current magnitude change when the compensation is not applied.

[0039] Figure 10B is an example diagram showing the current magnitude change when the compensation of the embodiment is applied.

[0040] Figure 11 is an example diagram showing the vibration improvement rate when the compensation of the embodiment is applied.

[0041] BRIEF DESCRIPTION OF DRAWINGS

[0042] 10: control device 11: inverter section

[0043] 12: control section 100: compressor DETAILED DESCRIPTION

[0044] Hereinafter, the embodiments disclosed in the present specification will be described in detail with reference to the accompanying drawings, and the same or similar constituent elements are designated by the same numeral references regardless of the numerals in the drawings and their description will be omitted. In describing the embodiments disclosed in the present specification, if it is determined that the specific description of related known functions or configurations can obscure the gist of the embodiments disclosed in the present specification, the detailed description thereof will be omitted.

[0045] In addition, it should be understood that the drawings are for ease of understanding of the embodiments disclosed in the present specification, and the technical idea disclosed in the present specification is not limited by the drawings, but encompasses all modifications, equivalents, and even alternatives included in the idea and technical scope of the present invention.

[0046] <Basic structure of compressor>

[0047] First, referring to Figure 1 and Figure 2 , a basic structure of a compressor to which the embodiments are applied will be exemplified.

[0048] Figure 1 and Figure 2 , the compressor shown in the drawings shows an example of a hermetic reciprocating compressor, and the embodiments of the present specification can be implemented differently from the example shown in Figure 1 and Figure 2 , and can be applied to other compressors different from the example shown in

[0049] Referring to Figure 1 and Figure 2 , the compressor 100 as an example includes a housing 110 forming an appearance, a motor portion 120 provided in an inner space 110a of the housing 110 and providing a driving force, a compression portion 130 receiving the driving force from the motor portion 120 and compressing a refrigerant, a suction and discharge portion 140 guiding the refrigerant to a compression chamber and discharging the compressed refrigerant, and a support portion 150 supporting a compressor main body C including the motor portion 120 and the compression portion 130 to the housing.

[0050] The inner space 110a of the housing 110 is hermetically sealed and accommodates the motor portion 120 and the compression portion 130. The housing 110 is composed of an aluminum alloy (hereinafter, simply referred to as aluminum) that is light in weight and has high thermal conductivity, and includes a base housing 111 and a cover housing 112.

[0051] The base housing 111 is formed in a substantially hemispherical shape. A suction pipe 115, a discharge pipe 116, and a process pipe are respectively coupled to the base housing 111. The suction pipe 115, the discharge pipe 116, and the process pipe can be respectively coupled to the base housing 111 by insert die casting.

[0052] Further, a cover seating surface 111a for seating the first spring cover 152 described later can be formed on the bottom surface of the base housing 111, and a cover receiving groove 111b for supporting the first spring cover 152 can be formed on the cover seating surface 111a.

[0053] The cover seating surface 111a can be formed in a ring shape on the entire bottom surface of the base housing 111, but can also be formed corresponding to the number of the first spring cover (or support spring) 152. For example, as shown in the present embodiment, when the first spring cover 152 is arranged in four places in a radial manner, the cover seating surface can also be formed in four places on the bottom surface of the base housing in a radial manner.

[0054] The cover seating surface 111a can be formed with the cover receiving groove 111b and a cover fixing groove.

[0055] The cover receiving groove 111b can be formed corresponding to the shape of the lower surface of the first spring cover 152 described later. Specifically, a first cover support protrusion that protrudes more as it approaches the center can be formed on a first cover fixing surface that constitutes the lower surface of the first spring cover 152. Thereby, the cover receiving groove 111b can be formed in a shape that is recessed more as it approaches the center, to correspond to the first cover support protrusion.

[0056] The cover fixing groove can be formed corresponding to a cover fixing protrusion provided on the lower surface of the first spring cover described later. Specifically, the cover fixing groove can be formed recessed inside the cover receiving groove 111b in a cross-sectional shape with corners like a cuboid. Thereby, the contact area with the cover fixing protrusion described later is increased, so that the first spring cover 152 can be effectively inhibited from being pushed radially.

[0057] Although not shown in the drawings, the positions of the cover fixing protrusion and the cover fixing groove can also be formed in reverse to the above-described embodiment. For example, the cover fixing protrusion can be formed on the cover seating surface of the base housing, and the cover fixing groove opposite thereto can be formed on the cover fixing surface of the first spring cover.

[0058] The cover housing 112 is formed in a substantially hemispherical shape like the base housing 111. The cover housing 112 is coupled to the base housing 111 on the upper side of the base housing 111, and forms the internal space 110a of the housing 110.

[0059] Further, the cover housing 112 and the base housing 111 can be coupled by welding, but when the base housing 111 and the cover housing 112 are formed of aluminum material that is difficult to weld, fastening can be performed using a bolt.

[0060] Next, the motor portion will be described.

[0061] Referring to Figure 1 and Figure 2 , the motor portion 120 as an example includes a stator 121 and a rotor 122.

[0062] The stator 121 is elastically supported to the bottom surface of the inner space 110a of the housing 110, i.e., the base housing 111, and the rotor 122 is rotatably provided inside the stator 121.

[0063] The stator 121 of the present embodiment includes a stator core 1211 and a stator coil 1212.

[0064] The stator core 1211 is composed of a metal material such as an electrical steel sheet, and, when a voltage is applied to the motor portion 120 from the outside, the stator core 1211 interacts electromagnetically with the stator coil 1212 and the rotor 122 described later by electromagnetic force.

[0065] In addition, the stator core 1211 is formed in a substantially rectangular cylindrical shape. For example, the inner peripheral surface of the stator core 1211 can be formed in a circular shape, and the outer peripheral surface thereof can be formed in a rectangular shape. Bolt holes (refer to Figure 9 ) are formed so as to respectively pass through the four corner portions of the stator core 1211, and stator fastening bolts respectively pass through the respective bolt holes and are fastened to the cylinder block 131 described later. Thus, the stator core 1211 can be fixed to the lower surface of the cylinder block 131 by the stator fastening bolts.

[0066] In addition, in a state in which the stator core 1211 is spaced apart from the inner surface of the housing 110 in the axial and radial directions, the lower end of the stator core 1211 is supported to the bottom surface of the housing 110 by the support spring 151 described later. Thus, it is possible to suppress the vibration generated during operation from being directly transmitted to the housing 110.

[0067] The stator coil 1212 is wound around the inside of the stator core 1211. As described above, when a voltage is applied from the outside, the stator coil 1212 generates electromagnetic force and interacts electromagnetically with the stator core 1211 and the rotor 122. Thus, the motor portion 120 generates a driving force for reciprocating the compression portion 130.

[0068] An insulator 1213 is disposed between the stator core 1211 and the stator coil 1212. Thus, it is possible to suppress direct contact between the stator core 1211 and the stator coil 1212, so that electromagnetic interaction can be smoothly performed.

[0069] The rotor 122 includes a rotor core 1221 and a magnet 1222, as an example.

[0070] Like the stator core 1211, the rotor core 1221 is composed of a metal material such as an electrical steel sheet and is formed in a substantially cylindrical shape. The crankshaft 125 described later can be press-fitted and coupled to the center of the rotor core 1221.

[0071] The magnet 1222 is formed of a permanent magnet and can be inserted at equal intervals along the circumferential direction of the rotor core 1221 in combination with the rotor core 1221. When a voltage is applied, the rotor 122 rotates by electromagnetic interaction with the stator core 1211 and the stator coil 1212. Thereby, the crankshaft 125 transmits the rotational force of the motor portion 120 to the compression portion 130 via the connecting rod 126 while rotating together with the rotor 122.

[0072] Next, the compression portion will be described.

[0073] Referring to Figure 1 and Figure 2 , the compression portion 130 includes a cylinder 131 and a piston 132 as an example. The cylinder 131 is elastically supported to the housing 110, and the piston 132 is combined to the crankshaft 125 via the connecting rod 126 and relatively moves with respect to the cylinder 131.

[0074] The cylinder 131 is provided at the upper side of the motor portion 120 as an example. The cylinder 131 includes a frame portion 1311, a fixing protrusion 1312 combined to the stator 121 of the motor portion 120, a bearing portion 1313 supporting the crankshaft 125, and a cylinder tube portion 1315 forming a compression chamber V.

[0075] The frame portion 1311 can be formed in a flat plate shape extending in the lateral direction, or can be formed in a radiating plate shape by weight-reducing processing of a part of the edge except for the corner portion.

[0076] The fixing protrusion 1312 is formed at the edge of the frame portion 1311. For example, the fixing protrusion 1312 can be formed to protrude downward from the edge of the frame portion 1311 toward the motor portion 120.

[0077] In addition, a fastening hole (not shown) is formed in the fixing protrusion 1312 to communicate with the bolt hole provided in the stator 121. Thereby, the cylinder 131 can be fastened to the stator 121 by the stator fastening bolt to be described later, and can be elastically supported to the base housing 111 together with the stator 121 of the motor portion 120.

[0078] The bearing portion 1313 can be formed to extend from the central portion of the frame portion 1311 in the axial direction to both sides. A bearing hole 1313a is formed in the bearing portion 1313 in the axial direction to pass through the crankshaft 125, and a bush bearing can be inserted in combination with the inner circumferential surface of the bearing hole 1313a.

[0079] In addition, the plate portion of the crankshaft 125 can be supported in the axial direction by the upper end of the bearing portion 1313, and the support portion of the crankshaft 125 can be supported in the radial direction by the inner circumferential surface of the bearing portion 1313. Thereby, the crankshaft 125 can be supported in the axial and radial directions by the cylinder 131.

[0080] A cylinder portion (hereinafter, referred to as a cylinder) 1315 is formed eccentrically in a radial direction from a side edge of the frame portion 1311. The cylinder 1315 is perforated in the radial direction, and a piston 132 connected to the connecting rod 126 is inserted into an inner side opening end thereof, and a valve assembly 141 constituting a suction and discharge portion 140 described later is attached to an outer side opening end thereof.

[0081] In the piston 132 as an example, a side (rear side) toward the connecting rod 126 is formed to be open, and a front side as the opposite side is formed to be closed. Thus, the connecting rod 126 is inserted into the rear side of the piston 132 and rotatably coupled, and since the front side of the piston 132 is formed to be closed, a compression chamber V is formed together with the valve assembly 141 described later in the inside of the cylinder 1315.

[0082] In addition, the piston 132 can be made of the same material as the cylinder 131, for example, an aluminum alloy. Thus, the magnetic flux can be suppressed from being transmitted from the rotor 122 to the piston 132.

[0083] In addition, since the piston 132 is formed of the same material as the cylinder 131, the thermal expansion coefficients of the piston 132 and the cylinder (specifically, the cylinder) 131 are the same. Thus, even when the inside space 110a of the housing 110 is in a high temperature state (approximately 100°C) at the time of driving of the compressor 100, interference due to thermal expansion between the cylinder 131 and the piston 132 can be suppressed.

[0084] Next, the suction and discharge portion will be described.

[0085] Referring to Figure 1 and Figure 2 , the suction and discharge portion 140 as an example includes the valve assembly 141, a suction muffler 142, and a discharge muffler 143. The valve assembly 141 and the suction muffler 142 are coupled to the outer side opening end of the cylinder 1315 in this order.

[0086] The valve assembly 141 as an example includes a suction valve 1411 and a discharge valve 1412, and is coupled to the end portion of the cylinder 131. The suction valve 1411 and the discharge valve 1412 can be provided separately, but generally, can be formed together in the same valve plate.

[0087] The suction valve 1411 is opened and closed in the direction of the piston 132, and the discharge valve 1412 is formed to be opened and closed in the direction opposite to the suction valve 1411. Thus, a separate retainer is not provided in the suction valve 1411, but a retainer (not labeled with a reference numeral) which limits the opening degree of the discharge valve 1412 can be provided in the discharge valve 1412.

[0088] In addition, the valve assembly 141 may further include a valve plate 1413 supporting the suction valve 1411 , and a cylinder cover 1414 coupled to the valve plate 1413 and supporting the suction muffler 142 .

[0089] The valve plate 1413 is bolted to the cylinder body 131 together with a cylinder cover 1414 . A discharge space S is formed in the cylinder cover 1414 , and can be connected to a discharge muffler 143 described later via an annular pipe 118 .

[0090] The suction muffler 142, for example, transfers the refrigerant sucked through the suction pipe 116 to the compression chamber V of the cylinder 1315. The suction muffler 142 may be fixed to the end surface of the cylinder 131 via the valve assembly 141 or a separate clamp (not shown).

[0091] A suction space (not denoted by a reference numeral) is formed inside the suction muffler 142 . The inlet of the suction space communicates directly or indirectly with the suction pipe 115 , and the outlet of the suction space communicates directly with the suction side of the valve assembly 141 .

[0092] As an example, the discharge muffler 143 may be provided separately from the cylinder 131 .

[0093] A discharge space (not denoted by a reference numeral) is formed inside the discharge muffler 143 . The inlet of the discharge space can be connected to the discharge side of the valve assembly 141 via the annular tube 118 , and the outlet of the discharge space can be directly connected to the discharge pipe 116 via the annular tube 118 .

[0094] <Compressor Control Device>

[0095] Hereinafter, an embodiment of a control device for a compressor (hereinafter referred to as a control device) will be described.

[0096] like Figure 3 As shown, the control device 10 includes an inverter unit 11 and a control unit 12, and controls the Figure 1 and Figure 2 The control device for the operation of the compressor 100 is shown.

[0097] The control device 10 may control the operation of the compressor 100 by supplying driving power to the motor of the compressor 100 .

[0098] The control device 10 may control the operation of the compressor 100 by controlling the driving of the motor in an inverter manner.

[0099] That is, the control device 10 may be an inverter that controls the operation of the compressor 100 , or may be a device including the inverter.

[0100] The control device 10 controls the driving power source applied to the motor by controlling the switching operation of the inverter, and thereby controls the driving of the motor.

[0101] The control device 10 controls the driving power source by controlling the switching operation, and thereby controls the driving of the motor, and thereby controls the operation of the compressor 100.

[0102] The detailed circuit diagram of the control device 10 as shown in FIG. 1 can be as shown in FIG. 2. Figure 3 Figure 4

[0103] In the control device 10, the inverter part 11 converts the power source input from the external power source 1 into a driving power source for driving the motor of the compressor 100, and applies it to the motor.

[0104] The inverter part 11 can be connected to the motor, converts the alternating current power source input from the external power source 1 into a direct current power source, converts the direct current power source into the driving power source, and outputs the driving power source to the motor.

[0105] The motor can be a three-phase motor for driving the compressor C, and the driving power source can be in the form of a three-phase alternating current power source.

[0106] The inverter part 11 can convert the direct current power source into the driving power source in the form of an alternating current power source by switching operation, and output it to the motor.

[0107] The inverter part 11 can include a plurality of switching modules that convert the direct current power source into a three-phase alternating current power source.

[0108] Preferably, the plurality of switching modules can be Insulated Gate Bipolar Transistor (IGBT) modules.

[0109] The switching operation of the plurality of switching modules can be controlled by the control part 12.

[0110] That is, the inverter part 11 can be controlled by the control part 12.

[0111] The plurality of switching modules can receive a control signal for the switching operation from the control part 12, and perform switching operation according to the control signal to convert the direct current power source into the alternating current power source.

[0112] ​​That is, the switching operation of the inverter section 11 is controlled by the control section 12, and the drive power source is controlled by the switching operation, so that the driving of the motor can be controlled.

[0113] In the control device 10, the control section 12 detects one or more of the magnitude of the drive power source, the position of the piston of the compressor 100, and the internal pressure of the cylinder in which the piston reciprocates, generates a PWM (Pulse Width Modulation) control signal for controlling the switching operation of the inverter section 11 based on the detection result, and controls the switching operation by applying the control signal to the inverter section 11.

[0114] The control signal is a signal for controlling the switching operation by adjusting the duty ratio of the switching module.

[0115] That is, the control section 12 can control the switching operation in a PWM control manner.

[0116] The control section 12 can control the current applied to the motor by adjusting the duty ratio of the control signal.

[0117] The control section 12 can generate a control instruction based on the detection result, and determine one or more of a command voltage for the motor voltage, a command current for the motor current, a speed command for the operating speed of the motor, and a frequency command for the switching frequency of the motor based on the control instruction, and generate the control signal based on the determination result.

[0118] Thus, feedback control of the compressor 100 can be performed.

[0119] The control section 12 can determine the operating range of the compressor 100 or the stroke of the compressor 100 based on the detection result, and can generate the control signal based on the determination result.

[0120] For example, it can be determined whether the compressor 100 is performing a compression stroke based on a change in the internal pressure, and the control signal can be generated to perform corresponding control during the compression stroke.

[0121] The control section 12 can be composed of a plurality of controllers, and the control signal can be generated by an arithmetic process in the plurality of controllers.

[0122] For example, as Figure 4As shown, the control section 12 can include one or more of a position detector, a start condition determiner, a rotational position determiner, a speed converter, a speed controller, a compensation value calculator, and a PWM switching signal generator, and the control signal can be generated by performing calculations in each of the plurality of controllers.

[0123] The control section 12 as described above generates the control signal by compensating the duty ratio of the control signal differently for each of when the compressor 100 performs a compression stroke and when the compressor 100 performs a suction stroke.

[0124] That is, the control section 12 can change the compensation of the duty ratio and generate the control signal according to the stroke performed by the compressor 100.

[0125] Thus, the compensation of the duty ratio when the compression stroke is performed and the compensation of the duty ratio when the suction stroke is performed can be different.

[0126] Here, the compression stroke and the suction stroke can refer to a stroke interval divided according to the operating principle characteristics of the compressor 100.

[0127] Thus, the control device 10 can change the compensation of the duty ratio according to the stroke interval of the compressor 100 divided according to the operating principle characteristics.

[0128] The respective intervals of the compression stroke and the suction stroke in which the duty ratio is compensated differently can be as shown. Figure 5

[0129] The compression stroke, which refers to an interval in which the piston advances from the bottom dead center (BDC) to the top dead center (TDC) and compresses air so that the internal pressure of the cylinder rises to a reference value, can include a compression interval C1-1, C1-2, and a valve opening interval C0.

[0130] The suction stroke, which refers to an interval in which the piston retreats from the top dead center (TDC) to the bottom dead center (BDC) and sucks in air so that the internal pressure decreases to a reference value, can include a re-expansion interval C2-1 and a suction interval C2-2.

[0131] The control section 12 can determine the current stroke interval of the compressor 100 based on one or more of the detection results of the size of the driving power source, the position, and the internal pressure, and compensate the duty ratio and generate the control signal according to the determined stroke interval.

[0132] For example, the control section 12 can be implemented as a microcomputer including a CPU, a ROM, a RAM, and the like, and can be implemented as a hardware circuit such as an ASIC. Figure 5 ​The control section 12 can judge the current stroke section based on the detection result of one or more of the magnitude of the current and the internal pressure, and the change in the current or the change in the internal pressure in each section.

[0133] In Figure 5 , the left vertical axis can refer to the RMS (Root Mean Square) ratio value of the current, and the right vertical axis can refer to the magnitude value of the internal pressure.

[0134] The compensation of the stroke section according to the duty ratio can be performed as Figure 6 indicated.

[0135] In the execution of the compression stroke, the control section 12 can generate the control signal by positively (+) compensating the duty ratio of the control signal in a predetermined first section C1-1, C1-2.

[0136] Here, the meaning that the duty ratio is compensated in the first section C1-1, C1-2 can mean that the duty ratio is compensated in at least a part of the section of the first section C1-1, C1-2.

[0137] In the following description, the meaning that the duty ratio is compensated in an arbitrary section can mean that the duty ratio is compensated in at least a part of the section of the arbitrary section.

[0138] The first section C1-1, C1-2 can be at least a part of the compression section of the compression stroke.

[0139] The first section C1-1, C1-2 can be a section from a time point at which the piston is located at the bottom dead center to a time point at which the valve of the cylinder is opened.

[0140] That is, the control section 12 can generate the control signal by compensating the duty ratio with a positive (+) compensation value in the first section C1-1, C1-2 from the time point at which the piston is located at the bottom dead center to the time point at which the valve of the cylinder is opened.

[0141] As Figure 6 indicated, the control section 12 can generate the control signal by increasing the compensation value of the duty ratio in stages in the first section C1-1, C1-2.

[0142] That is, the compensation of the duty ratio can be increased in stages in the first section C1-1, C1-2.

[0143] For example, an arbitrary compensation value is compensated in the first-1 section C1-1, and a compensation value greater than the arbitrary compensation value is compensated in the first-2 section C1-2, so that the compensation can be increased in stages.

[0144] The control section 12 can compensate the duty ratio by a first-1 compensation value x% in a first-1 section C1-1 in the first section C1-1, C1-2, from a time point at which the piston is located at a bottom dead center to a time point at which the piston moves to a specific position.

[0145] The first-1 section C1-1 can be a compression initial section of the compression stroke.

[0146] That is, the control section 12 can generate the control signal by compensating the duty ratio by the first-1 compensation value x% in the first-1 section C1-1, corresponding to the compression initial section, from the time point at which the piston is located at the bottom dead center to the time point at which the piston moves to the specific position.

[0147] The control section 12 can compensate the duty ratio by a first-2 compensation value ax% greater than the first-1 compensation value in a first-2 section C1-2 in the first section C1-1, C1-2, from a time point at which the piston is located at the specific position to a time point at which a valve of the cylinder is opened.

[0148] The first-2 section C1-2 can be a compression increase section of the compression stroke.

[0149] That is, the control section 12 can generate the control signal by compensating the duty ratio by the first-2 compensation value ax% greater than the first-1 compensation value x% in the first-2 section C1-2, corresponding to the compression increase section, from the time point at which the piston is located at the specific position to the time point at which the valve of the cylinder is opened.

[0150] The first-1 compensation value x% can be a numerical value x% representing a compensation value of the duty ratio.

[0151] For example, the first-1 compensation value x% can be 50%.

[0152] The first-2 compensation value ax% can be a constant multiple a of the first-1 compensation value x%.

[0153] For example, the first-2 compensation value ax% can be twice, i.e., 100%, of the first-1 compensation value x%.

[0154] Thus, the compensation of the duty ratio in the compression increase section C1-2 can be increased by the constant multiple a from the compression initial section C1-1, so that the compensation of the duty ratio can be increased in stages in the compression stroke section.

[0155] In the execution of the suction stroke, the control section 12 can generate the control signal by negatively (-) compensating the duty ratio of the control signal in a preset second interval C2-1.

[0156] The second interval C2-1, C2-2 can be an interval of at least a portion of the suction stroke.

[0157] The second interval C2-1, C2-2 can include at least a portion of a re-expansion interval in the suction stroke.

[0158] The second interval C2-1, C2-2 can include an interval C2-1 from a time point that is a constant time earlier than a time point at which the piston is at the top dead center to a time point at which the discharge of the air compressed in the cylinder ends.

[0159] That is, the control section 12 can generate the control signal by compensating the duty ratio by a negative (-) compensation value in the interval C2-1 from the time point that is a constant time earlier than the time point at which the piston is at the top dead center to the time point at which the discharge of the air compressed in the cylinder ends.

[0160] In which, the interval from the time point that is a constant time earlier than the time point at which the piston is at the top dead center to the time point at which the discharge of the air compressed in the cylinder ends can be the re-expansion interval C2-1.

[0161] Thus, the control section 12 can generate the control signal by compensating the duty ratio by a negative (-) compensation value in the re-expansion interval C2-1.

[0162] In which, the re-expansion interval C2-1 can include an interval in which the piston retreats due to the re-expansion of the residual gas that is not discharged.

[0163] That is, in the re-expansion interval C2-1 from the time point that is a constant time earlier than the time point at which the piston is at the top dead center to the time point at which the discharge of the air compressed in the cylinder ends, the piston can retreat by the re-expansion of the residual gas that is not discharged.

[0164] As shown in FIG. 6, the control section 12 can compensate the duty ratio by a second compensation value x% in the second interval C2-1, C2-2. Figure 6 In which, the second compensation value x% can be a negative (-) compensation value, and can be the same value as the first-1 compensation value x%.

[0165] For example, when the first compensation value x% is 50%, the second compensation value x% can be -50%.

[0166]

[0167] ​Thus, in the second interval C2-1, C2-2, negative compensation of an amount corresponding to the positive compensation value of the compression initial interval C1-1 can be performed.

[0168] The second interval C2-1, C2-2 can further include an interval C2-2 from a time point at which discharge of air compressed in the cylinder is completed to a time point at which the piston is located at a bottom dead center.

[0169] For example, at least a portion of a suction interval of the suction stroke can also be included.

[0170] In this case, the second interval C2-1, C2-2 can be divided into the re-expansion interval C2-1 corresponding to the second-1 interval and the suction interval C2-2 corresponding to the second-2 interval, and compensation of the duty ratio can also be performed in the suction interval C2-2.

[0171] For example, the duty ratio can be compensated by a second-2 compensation value bx% in the suction interval C2-2.

[0172] On the other hand, in a case in which the second interval C2-1, C2-2 includes the second-2 interval C2-2, the control portion 12 can also gradually increase the compensation value of the duty ratio and generate the control signal in the second interval C2-1, C2-2.

[0173] For example, an arbitrary compensation value can be compensated in the second-1 interval C2-1, and a compensation value smaller than the arbitrary compensation value can be compensated in the second-2 interval C2-2, so that the compensation can be gradually increased.

[0174] In this case, since negative (-) compensation is performed in the second interval C2-1, C2-2, a case in which the compensation value decreases as an absolute value can refer to a case in which the compensation is eventually increased.

[0175] As described above, the control portion 12 changes compensation of the duty ratio by the stroke interval by performing positive (+) compensation of the duty ratio during the compression stroke and negative (-) compensation of the duty ratio during the suction stroke, and the control portion 12 can compensate the duty ratio during the compression stroke and the duty ratio during the suction stroke differently from each other when the compressor 100 operates at an operating frequency below a predetermined reference frequency.

[0176] That is, the control portion 12 can compensate the duty ratio during the compression stroke and the duty ratio during the suction stroke differently from each other when the compressor 100 operates below the reference frequency.

[0177] The reference frequency can be a frequency corresponding to a low-speed operating region.

[0178] The reference frequency can also be set to an operating speed of the compressor 100.

[0179] Thus, when the compressor 100 operates at a speed lower than the reference speed, the compensations for the compression stroke and the suction stroke can be made different.

[0180] <Compressor>

[0181] Hereinafter, an embodiment of a compressor will be described.

[0182] The compressor 100 includes a piston reciprocating by rotation of a motor, a cylinder in which the piston reciprocates, a valve restricting air inflow and outflow of the cylinder, and a control device 10 controlling operation of the compressor 100 by controlling a driving power source applied to the motor according to one or more of a magnitude of the driving power source, a position of the piston, and an internal pressure of the cylinder.

[0183] The control device 10 can be the aforementioned control device.

[0184] The control device 10 can also be a device different from the aforementioned control device.

[0185] Hereinafter, a part repeated from the aforementioned content will be omitted, and a specific embodiment of the compressor 100 will be mainly described.

[0186] In the compressor 100, when an operating speed of the compressor 100 is lower than a preset reference speed, the control device 10 controls operation of the compressor 100 by changing a compensation for a current applied to the motor according to a plurality of stroke intervals divided according to a change in the internal pressure.

[0187] That is, when the compressor 100 operates at a speed lower than the reference speed, the control device 10 can control operation of the compressor 100 by compensating the current differently according to the plurality of stroke intervals.

[0188] The reference speed can be a speed corresponding to a low-speed operation region.

[0189] The reference speed can also be set to an operating frequency of the compressor 100.

[0190] For example, it can be set to 15 Hz.

[0191] In this case, when the compressor 100 operates at a speed lower than 15 Hz, the control device 10 can control operation of the compressor 100 by compensating the current differently according to the plurality of stroke intervals.

[0192] The control device 10 can control the operation of the compressor 100 by detecting one or more of the size of the driving power supply, the position, and the internal pressure, and judging the currently executed stroke interval based on the detection result, and compensating the current compensation value corresponding to the judged stroke interval to the current.

[0193] For example, the currently executed travel section among the plurality of travel sections may be determined based on the change in the internal pressure.

[0194] like Figure 6 As shown, the plurality of stroke intervals are divided according to the change of the internal pressure, and may include: a compression initial interval C1-1 in which the internal pressure increases to a preset baseline size; a compression increase interval C1-2 in which the internal pressure increases at a preset increase ratio or above; a valve opening interval C0 in which the internal pressure changes within a preset rising range; a re-expansion interval C2-1 in which the internal pressure decreases at a preset decrease ratio or above; and a suction interval C2-2 in which the internal pressure changes within a preset minimum range.

[0195] That is, the control device 10 may determine the currently executed stroke section among the compression initial section C1-1, the compression increase section C1-2, the valve opening section C0, the re-expansion section C2-1, and the suction section C2-2 based on the detection result.

[0196] In an embodiment of the compressor 100, preferably, the control device 10 can determine, based on the detection result of the internal pressure, whether the currently executed stroke interval is the compression initial interval C1-1, the compression increase interval C1-2, the valve opening interval C0, the re-expansion interval C2-1, and the suction interval C2-2.

[0197] The compression initial section C1-1 may be a section in which the internal pressure increases from a level when the piston is at the bottom dead center (BDC) to the reference level.

[0198] The reference level may be a level at which the internal pressure starts to increase at or above the increase rate.

[0199] That is, the compression initial section C1-1 may be a section in which the internal pressure increases from a level when the piston is at the bottom dead center BDC to the reference level.

[0200] Thus, when the internal pressure when the piston is located at the bottom dead center BDC is detected, the control device 10 can determine that the compressor 100 has entered the compression initial section C1-1.

[0201] The compression increase interval C1-2 can be an interval in which the internal pressure increases at more than the increase rate from the reference size.

[0202] The increase rate can be a constant differential value of the internal pressure.

[0203] That is, the compression increase interval C1-2 can be an interval in which the internal pressure increases at a slope of more than a constant differential value from the reference size.

[0204] Thereby, when the internal pressure size of the reference size is detected, the control device 10 can determine that the compressor 100 enters the compression increase interval C1-2.

[0205] The valve opening interval C0 can be an interval in which the internal pressure changes in the rising range after increasing at more than the increase rate.

[0206] The rising range can be a range of variation of a maximum value of the internal pressure.

[0207] That is, the valve opening interval C0 can be an interval in which the internal pressure changes in a range of variation of a maximum value of the internal pressure after increasing at more than the increase rate.

[0208] Thereby, when the internal pressure is detected to be a size that increases at more than the increase rate, the control device 10 can determine that the compressor 100 enters the valve opening interval C0.

[0209] Alternatively, it can also be determined that the compressor 100 enters the valve opening interval C0 by detecting the opening state of the valve.

[0210] The re-expansion interval C2-1 can be an interval in which the internal pressure decreases at more than the decrease rate after changing in the rising range.

[0211] The decrease rate can be a constant differential value of the internal pressure.

[0212] That is, the re-expansion interval C2-1 can be an interval in which the internal pressure decreases at a slope of more than a constant differential value after changing in the rising range.

[0213] Thereby, when the internal pressure is detected to be an internal pressure size that changes in the rising range, the control device 10 can determine that the compressor 100 enters the re-expansion interval C2-1.

[0214] The suction interval C2-2 can be an interval in which the internal pressure changes in the minimum range after decreasing at more than the decrease rate.

[0215] The minimum range can be a variation range of the minimum value of the internal pressure.

[0216] That is, the suction interval C2-2 can be an interval in which the magnitude of the internal pressure varies within the variation range of the minimum value of the internal pressure after being reduced by more than the reduction ratio.

[0217] Thus, when the internal pressure is detected to be of a magnitude reduced by more than the reduction ratio, the control device 10 can determine that the compressor 100 enters the suction interval C2-2.

[0218] As described above, the control device 10 that determines the current stroke interval can control the operation of the compressor 100 by applying different current compensation values to the current compensation in each of a plurality of the stroke intervals.

[0219] The compensation of the current can mean that the current is compensated and controlled by generating a control signal for controlling the current based on a control command to which a current compensation value is compensated, according to the control command reflecting the current compensation value.

[0220] Alternatively, it can also mean that the current is compensated and controlled according to the control signal reflecting the current compensation value by applying a duty compensation value corresponding to the current compensation value to the duty of the control signal.

[0221] The control device 10 can compensate the current by 50% of the compensation value in the compression initial interval C1-1.

[0222] That is, when the current stroke interval is the compression initial interval C1-1, the control device 10 can compensate the current by 50% of the compensation value.

[0223] The control device 10 can compensate the current by a compensation value greater than that of the compression initial interval C1-2 in the compression increase interval C1-2.

[0224] That is, when the current stroke interval is the compression increase interval C1-2, the control device 10 can compensate the current by a compensation value greater than that of the compression initial interval C1-2.

[0225] For example, when the current is compensated by 50% of the compensation value in the compression initial interval C1-1, the current can be compensated by 100% of the compensation value in the compression increase interval C1-2.

[0226] Thus, the control device 10 can control the compensation of the current to increase stepwise from the compression initial section C1-1 to the compression increase section C1-2.

[0227] The control device 10 can not compensate the current in the valve opening section CO.

[0228] That is, the control device 10 can not compensate the current when the current stroke section is the valve opening section CO.

[0229] The control device 10 can compensate the current by -50% of the compensation value in the reinflation section C2-1.

[0230] That is, the control device 10 can compensate the current by -50% of the compensation value when the current stroke section is the reinflation section C2-1.

[0231] The control device 10 can compensate the current by compensating the current in the suction section C2-2 by a compensation value that is smaller than that in the reinflation section C2-1.

[0232] The decrease in the compensation value can refer to a decrease in the absolute value.

[0233] That is, the control device 10 can compensate the current by a compensation value that is smaller in absolute value than that in the reinflation section C2-1 when the current stroke section is the suction section C2-2.

[0234] For example, when the current is compensated by -50% of the compensation value in the reinflation section C2-1, the current can be compensated by -25% of the compensation value in the suction section C2-2.

[0235] That is, the control device 10 can control the compensation of the current to increase stepwise from the reinflation section C2-1 to the suction section C2-2.

[0236] An example of the process in which the control device 10 described above controls the operation of the compressor 100 can be as shown in Figure 7

[0237] ​When the operation of the compressor 100 is started, the control device 10 controls the compressor 100 to operate at a low speed (P1), and judges whether the current load is less than an entry load (P2), and if the current load is the entry load or more, shifts to normal operation, and if the current load is less than the entry load, judges whether a target speed is less than a current speed (P3), and if the target speed is the current speed or more, shifts to normal operation, and if the target speed is less than the current speed, judges a current stroke interval (P4) based on one or more of the detected magnitude of the drive power source, the position, and the internal pressure.

[0238] Then, when the interval corresponding to the current stroke among the plurality of stroke intervals is judged, a compensation value corresponding to the judged current stroke interval can be applied to the duty ratio of the control signal (P5), and the control signal to which the compensation value is applied can be output to the motor (P6).

[0239] <Compressor control method>

[0240] Hereinafter, an embodiment of a compressor control method (hereinafter, referred to as a control method) will be described.

[0241] The control method can be a method in which the control device 10 described above controls the compressor 100.

[0242] The control method can also be a method in which the control section 12 of the control device 10 described above controls the compressor 100.

[0243] The control method can also be a control method of a device different from the control device described above.

[0244] Hereinafter, a part that is repetitive of the above will be omitted, and a specific embodiment of the control method will be mainly described, and an embodiment in which the control device 10 described above controls the compressor 100 will be mainly described.

[0245] The control method is a compressor control method of the control device 10 as shown in Figure 3 and Figure 4 Figure 8 ​As shown, it includes: a step (S1) of comparing the operating speed of the compressor 100 with a preset reference speed; when the operating speed is lower than the reference speed, based on the size of the driving power supply, the position of the piston of the compressor and one or more of the internal pressure of the cylinder for the reciprocating motion of the piston, a step (S2) of judging the stroke range of the compressor 100; based on the compensation reference preset differently according to the stroke range, a step (S3) of compensating the control instruction that serves as the basis for generating the control signal with a current compensation value corresponding to the current stroke range; and a step (S4) of generating the control signal according to the control instruction and applying it to the inverter unit 11.

[0246] That is, the control method can control the operation of the compressor 100 in the following order: the control device 10 determines the operating speed of the compressor 100 (S1), and when the compressor 100 operates below the reference speed, determines the stroke interval (S2), and compensates the control instruction with a current compensation value corresponding to the current stroke interval according to the compensation reference (S3), and generates the control signal according to the control instruction that compensates the current compensation value and applies it to the inverter unit 11.

[0247] The step ( S2 ) of determining the stroke range of the compressor 100 may be a step in which the control device 10 detects one or more of the magnitude of the driving power, the position, and the internal pressure, and determines the stroke range based on the detection results.

[0248] like Figure 6 As shown, the stroke interval may include: a compression initial interval C1-1 in which the internal pressure increases to a preset baseline size; a compression increase interval C1-2 in which the internal pressure increases at a preset increase ratio or above; a valve opening interval C0 in which the internal pressure changes within a preset rising range; a re-expansion interval C2-1 in which the internal pressure decreases at a preset decrease ratio or above; and a suction interval C2-2 in which the internal pressure changes within a preset minimum range.

[0249] Therefore, in the step (S2) of determining the stroke interval, the control device 10 can determine which of the compression initial interval C1-1, the compression increase interval C1-2, the valve opening interval C0, the re-expansion interval C2-1 and the suction interval C2-2 the current stroke interval is.

[0250] The step ( S3 ) of compensating the control command serving as a basis for generating the control signal with the current compensation value may be a step in which the control device 10 compensates the control command with the current compensation value corresponding to the current travel section based on the compensation reference.

[0251] The current compensation value can be set to a positive (+) compensation value in the compression initial section C1-1 and the compression increase section C1-2, and can be set to a negative (-) compensation value in the re-expansion section C2-1, with respect to the compensation reference.

[0252] Thus, in the step of judging the stroke section (S2), when the control device 10 judges that the current stroke section is the compression initial section C1-1 or the compression increase section C1-2, a positive (+) compensation value can be compensated to the control command in the step of compensating the control command (S3), and in the step of judging the stroke section (S2), when it is judged that the current stroke section is the re-expansion section C2-1, a negative (-) compensation value can be compensated to the control command in the step of compensating the control command (S3).

[0253] In addition, in the step of judging the stroke section (S2), when the control device 10 judges that the current stroke section is the valve opening section (CO), no compensation value can be compensated to the control command in the step of compensating the control command (S3).

[0254] That is, the control device 10 can not compensate a compensation value in the valve opening section (CO).

[0255] The compensation reference can also set the compensation value differently in each stroke section.

[0256] For example, a +x% compensation value can be set in the compression initial section C1-1, a larger ax% compensation value than the +x% compensation value in the compression initial section C1-1 can be set in the compression increase section C1-2, a -x% compensation value can be set in the re-expansion section C2-1, and a larger (in absolute value) -bx% compensation value than the -x% compensation value in the re-expansion section C2-1 can be set in the suction section C2-2.

[0257] The compensation value +ax% of the compression increase section C1-2 can be set to a compensation value that increases stepwise from the compensation value +x% of the compression initial section C1-1.

[0258] For example, it can be set to a constant multiple (a: a number of 2 or more) of the compensation value +x% of the compression initial section C1-1, that is, +ax%.

[0259] In addition, the compensation value -bx% of the suction section C2-2 can be set to a compensation value that increases stepwise from the compensation value -x% of the re-expansion section C2-1.

[0260] For example, a constant ratio (b: a number greater than 0 and less than 1) of the compensation value -x% of the re-expansion section C2-1 can be set.

[0261] In addition, the absolute values of the compensation value +x% of the compression initial section C1-1 and the compensation value -x% of the re-expansion section C2-1 can be set to be the same.

[0262] With the compensation reference being set as described above, the compensation value can be increased stepwise from the compression initial section C1-1 to the compression increase section C1-2, and the compensation value can be increased stepwise from the re-expansion section C2-1 to the suction section C2-2.

[0263] As described above, with the compensation value being increased stepwise and compensated, not only can the change in the current control be stably achieved, but also the sharp change in the current corresponding to the load can be limited.

[0264] In the case where the compensation reference is set as described above, in the step of compensating the control command (S3), when it is judged in the step of judging the stroke section (S2) that the current stroke section is the compression initial section C1-1, the control device 10 can compensate the control command by the compensation value +x% of the compression initial section C1-1, when it is judged in the step of judging the stroke section (S2) that the current stroke section is the compression increase section C1-2, the control device 10 can compensate the control command by the compensation value +ax% of the compression increase section C1-2, when it is judged in the step of judging the stroke section (S2) that the current stroke section is the valve opening section CO, the control device 10 can not compensate the control command by the compensation value, when it is judged in the step of judging the stroke section (S2) that the current stroke section is the re-expansion section C2-1, the control device 10 can compensate the control command by the compensation value -x% of the re-expansion section C2-1, and when it is judged in the step of judging the stroke section (S2) that the current stroke section is the suction section C2-2, the control device 10 can compensate the control command by the compensation value -bx% of the suction section C2-2.

[0265] In the step of generating the control signal according to the control command and applying it to the inverter section 11 (S4), the control device 10 generates the control signal according to the control command compensated according to the compensation reference and applies it to the inverter section 11, so that the current can be controlled according to the compensation of the current compensation value.

[0266] In the case where the operation of the compressor 100 is continued, after the step (S4) of generating the control signal in accordance with the control command and applying it to the inverter section 11, the control device 10 can repeatedly execute the step (Sl) of comparing the operation speed of the compressor 100 with the preset reference speed and the steps thereafter.

[0267] On the other hand, the control method can also be implemented in the order as shown in Figure 9

[0268] That is, another embodiment of the control method can be as shown in Figure 9

[0269] The control method as shown in Figure 9 includes the step (SlO) of compensating the duty ratio of the control signal by a first-1 compensation value from the time point at which the piston is located at the bottom dead center to the time point at which the piston moves to a certain position, the step (S20) of compensating the duty ratio by a first-2 compensation value which is larger than the first-1 compensation value from the time point at which the piston is located at the certain position to the time point at which the valve of the cylinder is opened, the step (S30) of not compensating the duty ratio by a compensation value from the time point at which the valve is opened to the time point which is a constant time ahead of the time point at which the piston is located at the top dead center, the step (S40) of compensating the duty ratio by a second-1 compensation value from the time point which is a constant time ahead of the time point at which the piston is located at the top dead center to the time point at which the discharge of the air compressed in the cylinder ends, and the step (S50) of compensating the duty ratio by a second-2 compensation value which is smaller than the second-1 compensation value from the time point at which the discharge of the air compressed in the cylinder ends to the time point at which the piston is located at the bottom dead center.

[0270] That is, the control method can control the operation of the compressor 100 in the order of the step (SlO) of compensating the duty ratio by the first-1 compensation value, the step (S20) of compensating the first-1 compensation value by the first-2 compensation value, the step (S30) of not compensating the compensation value, the step (S40) of compensating the second-1 compensation value, and the step (S50) of compensating the second-1 compensation value by the second-2 compensation value.

[0271] Thus, the control device 10 can sequentially execute the respective steps by compensating the duty ratio by the compensation values which are different from each other in each step.

[0272] ​​The step of compensating for the first-1 compensation value (S10) can be a step corresponding to the aforementioned compression initial interval C1-1, the step of compensating for the first-2 compensation value (S20) can be a step corresponding to the aforementioned compression increase interval C1-2, the step of not compensating for the compensation value (S30) can be a step corresponding to the aforementioned valve opening interval CO, the step of compensating for the second-1 compensation value (S40) can be a step corresponding to the aforementioned re-expansion interval C2-1, and the step of compensating for the second-2 compensation value (S50) can be a step corresponding to the aforementioned suction interval C2-2.

[0273] According to the control method as described above, the compressor 100 can be operated in the order of the compression initial interval C1-1 (S10) in which the duty ratio is compensated for the first-1 compensation value, the compression increase interval C1-2 (S20) in which the duty ratio is compensated for the first-2 compensation value, the valve opening interval CO (S30) in which the duty ratio is not compensated for the compensation value, the re-expansion interval C2-1 (S40) in which the duty ratio is compensated for the second-1 compensation value, and the suction interval C2-2 (S50) in which the duty ratio is compensated for the second-2 compensation value.

[0274] The above-described embodiments of the control method can be implemented by codes readable by a computer in a medium on which a program is recorded. The computer-readable medium includes all kinds of storage devices storing data readable by a computer system. The computer-readable medium is, for example, a hard disk drive (HDD), a solid state disk (SSD), a silicon disk drive (SDD), a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like, and can also be implemented in the form of a carrier wave (for example, transmission based on the Internet). In addition, the computer can also include the control device 100.

[0275] The control method as described above can also be applied with the control device 100 or a control algorithm and program for controlling a motor included in the control section 20 of the control device 100, an application, software, or the like.

[0276] <Effects of Embodiments>

[0277] Hereinafter, the effects of the aforementioned control device 10, compressor 100, and control method embodiments will be described with reference to the graphs regarding experimental charts.

[0278] Figure 10A and Figure 10Bare graphs showing current variation results of the non-compensation control and the control (with compensation) of the example at the operating frequency of 13 Hz, respectively, Figure 11 is a graph showing the vibration improvement rate when the compensation of the example is applied.

[0279] When compared with the non-compensation control at the operating frequency of 13 Hz, Figure 10A and Figure 10B it can be confirmed that the current magnitude is reduced by 21% to 27% in the control result of the example compared with the non-compensation control.

[0280] As described above, when the compensation control as shown in the example is applied in the low-speed operating region, not only the sharp current variation can be limited, but also the current magnitude can be reduced, so that the power consumption of the compressor can be reduced to improve the efficiency at the low-speed operation.

[0281] Figure 11 is a graph showing the vibration improvement rate in each case when the compensation control is applied only to the compression stroke (1st interval - compression), only to the suction stroke (2nd interval - re-expansion), and to both strokes with different compensation values, as shown in Figure 11 it can be confirmed that the vibration is improved by 46% when the compensation control is applied to both strokes with different compensation values, and the effect of the vibration improvement is great compared with the case when the compensation control is applied only to either interval.

[0282] Especially, Figure 11 The results shown in are bar graphs showing the results of the example, and it can be confirmed that the results of the example have a significant difference (46%) compared with the case when the results of the compensation control applied in each of the 1st and 2nd intervals are simply added (14% + 8%), and thus the results of the example are effects that cannot be predicted or expected by simply adding the compensation control for the 1st interval and the compensation control for the 2nd interval.

[0283] As described above, the description is made through the defined example and graph, but the present application is not limited to the described example, and various modifications and variations can be made from such description for those skilled in the art to which the present application pertains. Therefore, the present application is explained only by the claims, and the modifications equivalent or equivalent to the claims belong to the scope of the idea of the present application.

Claims

1. A compressor control device for controlling the operation of the compressor, characterized in that: include: an inverter unit that converts power input from an external power source into driving power for driving a motor of the compressor and applies the driving power to the motor; as well as a control unit that detects at least one of the magnitude of the driving power supply, the position of the piston of the compressor, and the internal pressure of a cylinder in which the piston reciprocates, generates a pulse width modulated control signal for controlling a switching operation of the inverter unit based on the detection result, and controls the switching operation by applying the control signal to the inverter unit. The control unit generates the control signal by compensating the duty ratio of the control signal in each of a section in which the compressor performs a compression stroke and a section in which the compressor performs a suction stroke so as to be different from each other. The control unit generates the control signal by performing negative (-) compensation on the duty ratio of the control signal during a preset second interval of the suction stroke. The second section is a section from a time point a constant time before a time point when the piston is located at the top dead center to a time point when discharge of the air compressed in the cylinder is completed.

2. The compressor control device according to claim 1, characterized in that: The control unit generates the control signal by performing positive (+) compensation on the duty ratio of the control signal in a predetermined first section during execution of the compression stroke.

3. The compressor control device according to claim 2, characterized in that: The first section is a section from the time when the piston is located at the bottom dead center to the time when the valve of the cylinder is opened.

4. The compressor control device according to claim 2, characterized in that: The control unit generates the control signal by gradually increasing the compensation value of the duty ratio in the first interval.

5. The compressor control device according to claim 4, characterized in that: The control unit compensates the duty ratio by a 1-1 compensation value in a 1-1 interval from a time point when the piston is at the bottom dead center to a time point when the piston moves to a specific position in the first interval, In a 1-2 interval from the time when the piston is located at the specific position to the time when the valve of the cylinder is opened, the duty ratio is compensated with a 1-2 compensation value that is larger than the 1-1 compensation value.

6. The compressor control device according to any one of claims 1 to 5, characterized in that: When the compressor is operated at an operating frequency lower than or equal to a preset reference frequency, the control unit compensates for the difference between the duty ratios in the compression stroke and the suction stroke.

7. A compressor, characterized in that: include: The piston reciprocates through the rotation of the motor; a cylinder, wherein the piston reciprocates within the cylinder; a valve to restrict the inflow and outflow of air into and out of the cylinder; as well as a control device for controlling the operation of the compressor by controlling the application of the driving power according to at least one of the magnitude of the driving power applied to the motor, the position of the piston, and the internal pressure of the cylinder; If the operating speed of the compressor is lower than a preset reference speed, the control device controls the operation of the compressor by changing the compensation of the current applied to the motor according to a plurality of stroke intervals divided according to the change in the internal pressure. The plurality of travel intervals include: The internal pressure increases to a preset reference level during the initial compression interval; a compression increase interval in which the internal pressure increases at a predetermined increase rate or higher; a valve opening interval in which the internal pressure varies within a preset rising range; a re-expansion interval in which the internal pressure is reduced at a predetermined reduction ratio or higher; and The internal pressure varies within a preset minimum range during the suction interval. The control device compensates the current by 50% of the compensation value in the initial compression interval. The control device compensates the current by a compensation value of -50% in the re-expansion interval.

8. A compressor control method, which is a method for controlling a compressor control device, the compressor control device comprising: an inverter unit that converts power input from an external power source into driving power for driving a motor of the compressor and applies the driving power to the motor; as well as a control unit that generates a pulse width modulated control signal for controlling a switching operation of the inverter unit and controls the switching operation by applying the control signal to the inverter unit; The compressor control method is characterized by comprising: comparing the operating speed of the compressor with a preset reference speed; If the operating speed is lower than the reference speed, determining a stroke range of the compressor based on at least one of the magnitude of the driving power supply, the position of the piston of the compressor, and the internal pressure of a cylinder in which the piston reciprocates; The step of compensating the control instruction serving as a basis for generating the control signal with a current compensation value corresponding to the current travel section based on compensation references preset differently for each travel section; and generating the control signal according to the control instruction and applying the control signal to the inverter unit; The travel interval includes: The internal pressure increases to a preset reference level during the initial compression interval; a compression increase interval in which the internal pressure increases at a predetermined increase rate or higher; a valve opening interval in which the internal pressure varies within a preset rising range; a re-expansion interval in which the internal pressure is reduced at a predetermined reduction ratio or higher; and The internal pressure varies within a preset minimum range during the suction interval. In the compression initial section and the compression increase section, the current compensation value of the compensation reference is set to a positive (+) compensation value, and in the re-expansion section, the current compensation value of the compensation reference is set to a negative (-) compensation value.

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