JP2003214353A - Control apparatus and control method for linear compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To regularly preset a thrust constant of a linear motor and thereby to improve reliability in drive control, in a drive control apparatus implementing protective control by using the thrust constant of a linear compressor. <P>SOLUTION: The control apparatus comprises: an auto-tuning means for calculating the thrust constant from induced voltage of the linear motor; and a means for presetting the thrust constant depending on an environmental condition or the drive condition. Therefore, the reliability of protective control is improved. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear compressor drive device which reciprocates a piston in a cylinder by a linear motor to generate compressed gas in a compression chamber formed by the cylinder and the piston.

[0002]

2. Description of the Related Art In recent years, a linear compressor has been developed as a mechanism for compressing a refrigerant gas in a refrigeration system.
For example, a conventional example proposed in Japanese Patent Laid-Open No. 11-324911 will be described with reference to FIG. As illustrated, a position command value generation unit (130), a position / speed control unit (131), a current command value generation unit (132), a position / speed detection unit (13).
3), top-bottom dead center detector (134), current / speed phase difference detector (135), current gain controller (136), amplitude neutral position controller (137), and frequency controller (138).
It consists of The position / velocity detector (133)
The position data Pa is taken from the sensor signal processing circuit to set the current position value Pnow and the current position value P
Differentiate now to obtain the current speed value Vnow. The top-bottom dead center detection unit (134), based on a series of current position values Pnow obtained from the position / velocity detection unit (133), determines the top dead center amplitude between the top dead center of the piston and the bottom dead center. The bottom dead center side amplitude between the point and the origin is detected. The top dead center side amplitude and the bottom dead center side amplitude are detected each time one cycle of the position command Pref is completed, that is, each time the position command Pref passes through the zero cross point. The current / speed phase difference detection unit (135) calculates the phase difference between the current position value Vnow generated by the position / speed detection unit (133) and the current command value Iref generated by the current command value generation unit (132). To detect.
The phase difference is detected every time one cycle of the current position value Pnow ends, that is, every time the current position value Pnow passes through the zero cross point. Position command value generation unit (130)
Is the sine table stored in the memory, the amplitude A,
The position command value Pr based on the angular frequency ω and the shift amount B
ef (Pref = Asin ωt + B (sine function)) is generated, and the generated position command value Pref is given to the position / speed control unit (131). The position / speed control unit (131)
Position command value P generated by the position command value generation unit (130)
The speed command value Vref is generated based on the deviation (Pref-Pnow) between the ref and the current position value Pnow generated by the position / speed detection unit (133), and the speed command value Vref is further generated.
The speed control value Vc is generated based on the deviation (Vref-Vnow) between ref and the current speed value Vnow generated by the position / speed detection unit (133). Current command value generator (1
32) is a current command value Iref based on the speed control value Vc generated by the position / speed control unit (131) and the current gain Gi output from the current gain control unit (136).
(Iref = Gi · Vc) is generated, and the current command value I
The ref is converted into the control signal φc and given to the motor driver. The output current I of the motor driver is controlled by, for example, the PWM method. Current gain controller (136)
Compares the top dead center side amplitude and the bottom dead center side amplitude detected by the top and bottom dead center detecting section (134), and the larger of the top dead center side amplitude and the bottom dead center side amplitude is the maximum amplitude. Current value An
ow, the value of the current gain Gi used in the current command value generation unit (132) is controlled for each cycle of the vibration of the piston so that the current maximum amplitude value Anow matches the predetermined maximum amplitude target value Aref. To do. Further, the current gain control section (136) determines whether the phase difference detected by the current / speed phase difference detection section (135) exceeds a predetermined allowable value once every several hundred cycles of piston vibration. If the current command value generation unit (1
32) Decrease the value of the current gain Gi used in 32) by several percent. In this way, the maximum amplitude control is performed in addition to the position / speed control by the position / speed control unit (131), and the current gain Gi is reduced by several% prior to the frequency control, so that the piston head and the cylinder are controlled. You can avoid collision with the wall. Furthermore, in order to avoid the collision of the piston when the load (gas pressure) suddenly drops, the magnitude between the target position of the top dead center of the piston and the limit position where the piston collides with the cylinder upper wall is increased or decreased. Set two excess judgment criteria. Regarding the large excess judgment criterion, when the current position value of the piston exceeds the excess judgment criterion, the gain Gi of the current gain control unit (136) is decreased by several tens of percent, and the small excess judgment criterion is When the average value of the top dead center position of the piston for 2 to several cycles exceeds the excess judgment criterion, the current gain control unit (13
The gain Gi of 6) is reduced by several percent. As a result, it is possible to reliably avoid a collision between the piston and the upper wall of the cylinder when the load (gas pressure) suddenly drops. The amplitude neutral position control section (137) includes an upper and lower dead center detection section (13
The position command value generating unit (130) compares the top dead center side amplitude and the bottom dead center side amplitude detected in 4) and reduces the difference between the top dead center side amplitude and the bottom dead center side amplitude. Shift amount B
Is controlled each time one cycle of the position command value Pref is completed. That is, if the amplitude at the top dead center side is larger than the amplitude at the bottom dead center side, the amplitude neutral position control unit (137) corrects the shift amount B to the negative side (downward), and the amplitude at the top dead center side is corrected. Is smaller than the bottom dead center side amplitude, the shift amount B is corrected to the positive side (upward direction). The processing flow will be described below with reference to FIG. In step 151, it is determined whether or not the current position value is greater than the excess judgment standard on the top dead center side. When the result is NO, the current position value is smaller than the excess judgment standard on the bottom dead center side in step 152. Determine if Step 15
When YES is determined in step 1 or YES is determined in step 152, there is a high risk of a piston collision, so the process proceeds to step 153, and the current gain is significantly reduced (for example, several tens%). When it is determined NO in step 152, the process proceeds to step 154 to detect whether the position command value has zero-crossed from the positive side to the negative side,
If yes, the process moves to step 155 and the third counter is incremented. Then, in step 156,
It is determined whether or not the value of the third counter has reached a set value (for example, 2 to 5). If the result is YES, in step 157, the maximum value of the piston position (collision avoidance) is set after the third counter is reset. The average value of (for processing) and the average value of the minimum position value (for collision avoidance processing) are calculated. Then, in step 158, it is determined whether or not the average value of the maximum position values (for collision avoidance processing) is larger than the excess judgment criterion on the top dead center side. It is determined whether the average value (for collision avoidance processing) is smaller than the excess judgment criterion on the bottom dead center side. If YES is determined in step 158 or YES is determined in step 159, there is a risk of piston collision, so the process proceeds to step 160 and the current gain is reduced by several percent. Next, in step 161, after resetting the maximum position value (for collision avoidance processing) and the minimum position value (for collision avoidance processing) that are held, in step 162, the third counter is reset, and the process proceeds to step 163. To do. Also, when it is determined no in step 154 and when it is determined no in step 156, the process proceeds to step 163, and the maximum position value (for collision avoidance processing) and minimum position value for the cycle are determined. Detects (for collision avoidance processing), holds and returns. According to the above collision avoidance routine, regarding the excess judgment criterion, when the position of the piston exceeds the judgment criterion in a certain cycle, the current gain is reduced by several tens of% at that time, and the collision of the piston is surely avoided. To be done. Regarding the excess judgment criterion, when the average value of the top dead center position or the bottom dead center position of the piston in 2 to several cycles exceeds the judgment criterion, the current gain is reduced by several% in the next cycle. The collision of the piston is avoided.

[0003]

However, the position of the piston of the linear compressor is calculated from the current, voltage, motor constant, mechanical system resonance frequency, etc. of the linear motor without using an operating transformer or Hall element, and highly efficient driving is achieved. Control or collision prevention control of piston and cylinder,
The motor constant of a linear motor, especially the thrust constant due to the neodymium magnet (thrust generated per unit current), is related to the design of the linear motor. It changes due to various factors such as the relative positional relationship of the fixed part core provided, the stroke amount of the movable part (piston), variations in mass production of magnets, deterioration over time, and temperature characteristics. In particular, variations in mass production of magnets, assembly accuracy, and aged deterioration of magnets have a large effect.When performing linear compressor drive control or protection control using the thrust constant of a motor at the initial design stage, if the magnet characteristics deteriorate, it will become one of the motor constants. The thrust constant is greatly reduced, the thrust constant changes due to the temperature characteristics of the magnet surface due to the difference in load conditions, and the moving part (piston) and fixed part (core part with windings) of the linear motor The thrust constant changes due to the large iron loss of the linear motor due to the relative positional relationship, the stroke amount of the piston, and the current. Therefore, when such a change occurs, unless the thrust constant is preset to the latest thrust constant by the auto-tuning means on a regular basis, the piston and the cylinder collide with each other, possibly damaging the linear compressor. Exists.

The present invention provides a controller for a linear compressor capable of presetting a thrust constant of a linear motor depending on variations in mass production of magnets of the linear motor, deterioration over time, demagnetization, temperature characteristics of the magnet, positional relationship of pistons, and the like. The purpose is to provide a control method.

[0005]

A control device for a linear compressor according to a first aspect of the present invention is a control device for a linear compressor in which a piston is driven by a linear motor in a cylinder to generate compressed gas. An inverter that outputs an alternating current supplied to the linear motor, a target current determination unit that determines a current flowing through the linear motor, and a power detection unit that detects an input power to the linear motor,
Driving frequency determining means for adjusting the frequency of the alternating current to determine the driving frequency, a current value command from the target current determining means and the inverter to create a current waveform corresponding to the driving frequency from the driving frequency determining means. Inverter control means for instructing and auto tuning means for presetting the parameter of the motor constant of the linear motor are provided. The linear compressor control method of the present invention according to claim 2, wherein an inverter for outputting an alternating current supplied to the linear motor, a target current determining means for determining a current flowing through the linear motor, and an input to the linear motor. Corresponding to the power detection means for detecting the power, the drive frequency determination means for adjusting the frequency of the alternating current to determine the drive frequency, the current value command from the target current determination means and the drive frequency from the drive frequency determination means. Inverter control means for instructing the inverter to create a current waveform, auto-tuning means for presetting motor constant parameters of the linear motor, and induced voltage detection means for detecting the induced voltage of the linear motor, A specific alternating current is applied to the linear motor by the inverter to drive the moving part of the linear motor. After that, the power supply to the inverter is stopped, and when the moving part of the linear motor is in the free-run state, the induced voltage of the linear motor is measured by the induced voltage detecting means, and at least the induced voltage is detected by the auto tuning means. It is characterized in that the thrust constant calculated from the voltage is preset. A control method for a linear compressor according to a third aspect of the present invention includes an inverter that outputs an alternating current supplied to a linear motor,
Target current determining means for determining the current flowing through the linear motor, power detecting means for detecting the input power to the linear motor, drive frequency determining means for adjusting the frequency of the alternating current and determining the drive frequency, and the target Inverter control means for instructing the inverter to create a current waveform corresponding to the current value command from the current determination means and the drive frequency from the drive frequency determination means, and auto-tuning for presetting the parameter of the motor constant of the linear motor Means, an induced voltage detection means for detecting an induced voltage of the linear motor, and an external forced vibration detection means for detecting that the movable portion of the linear motor is reciprocating by forced vibration from the outside, After the external forced vibration detection means detects the forced vibration from the outside, the induced voltage detection means, Measuring the induced voltage of the linear motors at the auto-tuning means, characterized by presetting the thrust constant calculated from at least the induced voltage. According to a fourth aspect of the present invention, there is provided a linear compressor control method, wherein an inverter that outputs an alternating current supplied to a linear motor, a target current determination unit that determines a current flowing through the linear motor, and an input to the linear motor. Corresponding to the power detection means for detecting the power, the drive frequency determination means for adjusting the frequency of the alternating current to determine the drive frequency, the current value command from the target current determination means and the drive frequency from the drive frequency determination means. Inverter control means for instructing the inverter to create a current waveform, auto-tuning means for presetting motor constant parameters of the linear motor, and piston stroke and top dead center position are calculated from at least the thrust constant of the linear motor. A piston position calculation means, and the piston position calculated by the piston position calculation means Based on the stroke and the amplitude center position information, in the auto-tuning means,
At least the thrust constant of the linear motor is calculated and preset. The linear compressor control method of the present invention according to claim 5, wherein an inverter that outputs an alternating current to be supplied to the linear motor, a target current determination means that determines a current flowing through the linear motor, and an input to the linear motor. Corresponding to the power detection means for detecting the power, the drive frequency determination means for adjusting the frequency of the alternating current to determine the drive frequency, the current value command from the target current determination means and the drive frequency from the drive frequency determination means. Inverter control means for instructing the inverter to create a current waveform, auto-tuning means for presetting motor constant parameters of the linear motor, induced voltage detection means for detecting induced voltage of the linear motor, and external forced vibration And an engine speed detecting means for detecting from the engine speed. After the external forced vibration is detected by the step, energization of the inverter is stopped, and when the moving part of the linear motor is in the free running state, the induced voltage of the linear motor is measured by the induced voltage detecting means, and the The tuning means presets at least a thrust constant calculated from the induced voltage. The present invention according to claim 6 is the method for controlling a linear compressor according to any one of claims 2 to 5, further comprising discharge temperature detection means for detecting a discharge temperature of a refrigerant of the linear compressor, The temperature of the magnet fixed to the movable portion of the linear motor is converted from the discharge temperature, and the thrust constant of the linear motor is corrected from the magnet temperature by the auto-tuning means. According to a seventh aspect of the present invention, there is provided a control method for a linear compressor, wherein an inverter for outputting an alternating current supplied to a linear motor, a target current determining means for determining a current flowing through the linear motor, and a frequency of the alternating current are adjusted. Drive frequency determining means for determining a drive frequency, and an inverter control means for instructing the inverter to create a current value command from the target current determining means and a current waveform corresponding to the drive frequency from the driving frequency determining means. An automatic tuning means for presetting a parameter of a motor constant of the linear motor, an induced voltage detecting means for detecting an induced voltage of the linear motor, an applied voltage detecting means for detecting a voltage applied to the linear motor, and the linear Current detecting means for detecting a motor current, the detected applied voltage and the detected motor voltage. When the phase difference detected by the phase detecting means is equal to or more than a set value, the auto tuning means presets at least a thrust constant calculated from the induced voltage. After the preset, the inverter is returned to normal drive control. The control method for a linear compressor according to the present invention according to claim 8, wherein an inverter that outputs an alternating current supplied to the linear motor, a target current determination unit that determines a current flowing through the linear motor, and an input to the linear motor. Corresponding to the power detection means for detecting the power, the drive frequency determination means for adjusting the frequency of the alternating current to determine the drive frequency, the current value command from the target current determination means and the drive frequency from the drive frequency determination means. Inverter control means for instructing the inverter to create a current waveform, auto-tuning means for presetting parameters of motor constants of the linear motor, induced voltage detection means for detecting induced voltage of the linear motor, and external External forced vibration detecting means for detecting forced vibration, wherein the external forced vibration detecting means is It determines that the forced vibration from the outside when the induced voltage is higher than the applied voltage applied to the motor,
After the external forced vibration detection means detects the forced vibration from the outside, the induced voltage detection means measures the induced voltage of the linear motor, and the auto tuning means,
At least the thrust constant calculated from the induced voltage is preset. The linear compressor control method of the present invention according to claim 9 is a controller for a linear compressor that drives a piston in a cylinder by a linear motor to generate compressed gas, and an alternating current supplied to the linear motor. , An inverter for outputting the target current, a target current determining means for determining the current flowing in the linear motor, a power detecting means for detecting the input power to the linear motor, and a drive frequency for determining the drive frequency by adjusting the frequency of the alternating current. Determining means, an inverter control means for instructing the inverter to create a current waveform corresponding to the current value command from the target current determining means and the drive frequency from the drive frequency determining means, and a motor constant of the linear motor. It is equipped with a preset means for presetting parameters, and at least the thrust constant is set after the linear compressor is assembled. Calculating a non-motor constant, characterized by memory the motor constant by the preset device.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION A control device for a linear compressor according to a first embodiment of the present invention comprises an inverter for outputting an alternating current supplied to a linear motor and a target current determining means for determining a current flowing through the linear motor. A power detection means for detecting the input power to the linear motor, a drive frequency determination means for adjusting the frequency of the alternating current and determining the drive frequency,
Inverter control means for instructing the inverter to create a current waveform corresponding to the current value command from the target current determination means and the drive frequency from the drive frequency determination means, and auto-tuning means for presetting the motor constant parameter of the linear motor It is equipped with. According to the present embodiment, by providing the auto-tuning means, the thrust constant of the linear motor due to variations in mass production of the linear motor magnet, deterioration over time, demagnetization, temperature characteristics of the magnet, positional relationship of the piston, etc. Alternatively, the control constants stored in, for example, the flash memory of the microcomputer or the data table of the serial PROM can be preset at regular intervals. When controlling the drive of the linear motor, for example, the magnet surface temperature is detected from the stroke amount of the piston, the center position of the amplitude, and the discharge temperature, and the auto tuning means calculates and presets according to the operating environment. You can

In the control method for the linear compressor according to the second embodiment of the present invention, the inverter energizes the linear motor with a specific alternating current to drive the movable portion of the linear motor, and then the energization of the inverter is stopped. Then, when the moving part of the linear motor is in the free-run state, the induced voltage of the linear motor is measured by the induced voltage detecting means and the thrust constant calculated from at least the induced voltage is preset by the auto tuning means. According to the present embodiment, since the thrust constant of the motor is calculated from the induced voltage of the linear motor, it is possible to find the thrust constant of the linear motor during mass production and according to a regular schedule, and preset the motor constant.

In the method for controlling a linear compressor according to the third embodiment of the present invention, after the external forced vibration detecting means detects the external forced vibration, the induced voltage detecting means measures the induced voltage of the linear motor. However, the auto-tuning means presets at least the thrust constant calculated from the induced voltage. According to the present embodiment, when mounted on an automobile or the like and fastened to a vibration source of external vibration such as an engine, it is detected that the movable portion of the linear motor is reciprocating due to forced vibration from the vibration source. Then, the induced voltage of the linear motor is measured by the induced voltage detecting means, and the thrust constant is calculated from the induced voltage.Therefore, it is not necessary to forcibly drive the linear motor by the inverter, so the thrust constant of the linear motor can be efficiently calculated. Can be preset.

A control method for a linear compressor according to a fourth embodiment of the present invention is based on the piston stroke and amplitude center position information calculated by the piston position calculation means.
At least the thrust constant of the linear motor is calculated and preset by the auto tuning means. According to the present embodiment, by calculating the thrust constant of the linear motor based on the stroke and amplitude center position information of the piston, even under various operating conditions such as the piston amplitude center, stroke amount, motor current, etc. The thrust constant of the motor can be preset, and particularly when the top dead center of the piston is calculated using the thrust constant to perform the collision prevention control, the detection accuracy can be improved and the drive control of the linear compressor with higher reliability can be performed.

In the control method for the linear compressor according to the fifth embodiment of the present invention, after the external forced vibration is detected by the engine speed detecting means, the energization of the inverter is stopped and the moving part of the linear motor is free running. In the state, the induced voltage of the linear motor is measured by the induced voltage detecting means, and the thrust constant calculated from at least the induced voltage is preset by the auto tuning means. According to the present embodiment, when an external vibration source such as an engine mounted on an automobile is present, the engine speed is detected, the preset mode, that is, the induced voltage of the linear motor is measured, and the thrust constant is calculated. Can be preset.

The sixth embodiment of the present invention has a discharge temperature detecting means for detecting the discharge temperature of the refrigerant of the linear compressor in the control method of the linear compressor according to the second to fifth embodiments. The temperature of the magnet fixed to the movable portion of the linear motor is converted from the discharge temperature, and the thrust constant of the linear motor is corrected from the magnet temperature by the auto tuning means. According to the present embodiment, it is possible to correct the thrust constant based on the temperature characteristic, and it is possible to perform more reliable drive control of the linear compressor.

In the control method for a linear compressor according to the seventh embodiment of the present invention, when the phase difference detected by the phase detecting means is equal to or larger than a set value, the thrust constant calculated from at least the induced voltage by the auto tuning means. Is preset, and the inverter is returned to normal drive control after presetting. According to the present embodiment, when the phase difference is equal to or larger than the set value, the auto tuning mode is entered. Furthermore, when the motor thrust constant is preset and the auto-tuning mode ends, normal drive control is immediately resumed, so the piston reciprocates continuously, so there is no sudden drop in performance and comfort is not impaired. .

In the control method for the linear compressor according to the eighth embodiment of the present invention, when the induced voltage is higher than the applied voltage applied to the linear motor, the external forced vibration detecting means detects the forced vibration from the outside. After determining that there is a forced vibration from the outside by the external forced vibration detection means, the induced voltage of the linear motor is measured by the induced voltage detection means, and the thrust constant calculated from at least the induced voltage by the auto tuning means. Is to be preset. According to the present embodiment, a sensor is not required when a vehicle is mounted on an automobile or the like and has a vibration source for external vibration such as an engine, and thus the cost is low and the reliability is high.

The control method for a linear compressor according to the ninth embodiment of the present invention is to calculate a motor constant including at least a thrust constant after assembling the linear compressor and store the motor constant in a preset means. . According to the present embodiment, when a linear compressor is mass-produced, the control program of the linear compressor is the same even if the motor specifications are different due to variations in magnet characteristics and model development, and the motor thrust is stored in the flash memory of the microcomputer. By presetting constants, it is possible to develop models with the same microcomputer and reduce mass production costs.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing the configuration of the linear compressor. A movable portion 204 of a linear motor having a magnet fixed thereto is fastened to the piston 207, and the piston rod 2
It is supported by the elastic container 205 in a closed container via 08. The fixed portion 202 of the linear motor is provided with the winding 203, and when a sine wave is energized by the inverter, the movable portion 2
By the electromagnetic action with 04, the piston 207 fastened to the movable portion 204 reciprocates in the cylinder 209. The refrigerant is sucked from the suction port, compressed in the compression chamber 206, and discharged into the discharge chamber 201. Piston 207
Since the relative positional relationship between the cylinder 209 and the cylinder 209 is affected by the pressure balance between the discharge pressure and the suction pressure, the elastic member 205
Of the compression chamber 206 and the gas spring constant of the compression chamber 206.

FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention. The DC power supply 101 that rectifies the AC voltage from the AC power supply 100 supplies the inverter 102 with the DC voltage. The inverter 102 is the inverter control means 1
The power element is switched according to the control command from 08, and a sinusoidal AC voltage is supplied to the linear compressor 103. The electric power detection unit 120 detects the voltage applied to the linear compressor 103 from the applied voltage detection unit 119 and the data from the current detection unit 106 that detects the current flowing through the linear compressor 103. Calculate the power on the primary side. Inverter control means 108
Is always based on the data from the current detection means 106 and the data from the target current determination means 122.
While the feedback control is performed so that the current flowing in 3 becomes the target current, the drive frequency determining unit 121 changes the drive frequency by several Hz around the drive frequency, and the power of the primary side of the linear motor detected by the power detecting unit 120 is detected. Is output to the inverter 102.
By setting the drive frequency at which the electric power on the primary side of the linear motor is maximized while the motor current is constant, highly efficient drive control can always be performed.

Here, the motor thrust constant has a great influence on the relative positional relationship between the piston 207 and the cylinder 209 due to the characteristics of the magnet fixed to the movable portion 204 of the linear motor shown in FIG. 1 and the configuration of the motor. The position detection accuracy of 207 is greatly affected. Therefore, the motor constant auto-tuning means 109 detects the induced voltage of at least the linear motor 104.
The thrust constant of the linear motor is regularly calculated based on the induced voltage value from the motor and the information from the current detection means 106, the motor constant is tuned periodically according to the calculation result, and the data is sent to the inverter control means 108. Thus, even if there is aged deterioration of the magnets, variations in mass production, demagnetization, changes in driving conditions, etc., the thrust constant is optimally auto-tuned periodically, so that highly reliable control can be realized.

FIG. 3 is a block diagram showing the structure of another embodiment. DC power is supplied from the DC power supply 101 to the inverter 102, the power element of the inverter 102 is switched according to a control command from the inverter control means 108, and a sinusoidal AC power is supplied to the linear compressor 103. The signal from the detector 107 that detects the current flowing through the linear compressor 103 is detected by the current detecting means 106. The induced voltage detecting means 104 detects a signal from a detector 105 which detects an induced voltage to the linear compressor 103. The presetting means 124 calculates the thrust constant of the linear motor based on the information from the induced voltage detecting means 104 and the current detecting means 106, and presets it in the inverter controlling means 108.

FIG. 4 is a control flow of the thrust constant auto-tuning means according to an embodiment of the present invention. When the auto tuning means is started (step 30
0), in step 301, the command current of Isinωt is output to the linear compressor, the resonance frequency of the drive system is tracked and controlled so as to become the resonance frequency of the mechanical system, and it is determined in step 302 whether or not the resonance frequency is reached. To do. When the resonance state is reached, the command current of the inverter is stopped in step 303. When the linear motor is in the free-run state due to the stop of the command current of the inverter, the induced voltage of the linear motor is measured by the induced voltage measuring means in step 304, and the current, voltage, frequency and amplitude value of the linear motor are measured in step 306. To measure. The induced voltage is approximately proportional to the magnetic flux density of the magnet, the frequency, and the amplitude value of the piston.
The thrust constant of the linear motor is calculated based on the basic database, and the data table is preset in step 307.

FIG. 5 is a diagram showing the relationship between the amplitude of the movable portion (piston) of the linear motor and the induced voltage of the linear motor. When the movable part of the linear motor is driven, an induced voltage is generated, and the induced voltage with respect to the amplitude of the movable part is
It can be seen that there is almost a proportional relationship.

Another embodiment of the present invention will be described with reference to FIGS. 6 and 7. FIG. 6 is a block diagram showing the configuration of the control device of this embodiment. In the case of a vehicle compressor, since the linear compressor 103 is attached to the mount of the engine 111, the movable portion (piston) of the linear compressor 103 is forcibly forced by the external vibration source by the forced vibration from the engine 111. Generates an induced voltage by being assisted by the force of. The signal from the induced voltage detector 105 of the linear motor is detected by the induced voltage detector 104, and the signal from the current detector 107 is detected by the current detector 106. Preset means 124
Calculates the thrust constant of the linear motor based on the information from the induced voltage detection means 104 and the current detection means 106, and presets it in the inverter control means 108.

FIG. 7 is a control flow of this embodiment. The forced vibration from the outside is detected in step 311, and if it is the forced vibration from the outside, the command current of the inverter is stopped in step 312 to put the motor in the free-run state. When the motor is in the free running state, the induced voltage of the linear motor is measured in step 313, and the frequency and current are measured in step 314. In step 315, the thrust constant is calculated from the information based on the basic database. Then, in step 316, the data is preset in the data table.

FIG. 8 is a control block diagram according to another embodiment of the present invention. The AC voltage from the AC power supply 100 is rectified by the DC power supply 101, and the rectified DC voltage is supplied to the inverter 102. The inverter 102 supplies a sine wave AC voltage to the linear compressor 103 according to a control command from the inverter control means 108. The power detection means 120 is an inverter 1 that supplies the linear compressor 103.
02. The electric power of the primary side of the linear compressor based on the data from the applied voltage detecting means 119 for detecting the voltage on the primary side or the secondary side and the data from the current detecting means 106 for detecting the current flowing through the linear compressor 103. To calculate. The inverter control means 108, based on the data from the current detection means 106 and the data from the target current determination means 122,
The feedback frequency is controlled so that the current flowing through the linear compressor 103 is always the target current, and the driving frequency determining means 121 is centered on the driving frequency and the number H before and after the driving frequency.
The frequency at which the primary side electric power of the linear motor detected by the electric power detection means 120 is changed to z is output to the inverter 102 as the next drive frequency. Highly efficient drive control can always be performed by changing the drive frequency at which the electric power becomes maximum at a constant current depending on the load. Current detection means 106
The linear compressor 103 is operated by the piston position calculation means 123 based on the current information from the motor, the voltage information from the applied voltage detector 119, and the drive frequency information from the drive frequency determiner 121.
The upper limit value, the lower limit value, the amplitude center value, and the stroke of the piston are calculated. Then, the motor constant auto-tuning means 109 calculates the optimum thrust constant of the linear motor from the piston position information, current, and frequency information, and presets the data table, so that the thrust constant changes due to changes in the environment. However, the control accuracy of the linear compressor can be improved, and the reliability can be improved.

Still another embodiment of the present invention will be described with reference to FIGS. 9 and 10. FIG. 9 is a control block diagram of this embodiment. A linear compressor 103, a four-way valve 118 for switching between heating and cooling, a heat exchanger (condenser) 113, an electric expansion valve 117, and a heat exchanger (evaporator) 115 are annularly connected to form a refrigeration cycle. To do. Blower fan for heat exchanger 1
Reference numeral 14 is provided for the heat exchanger (condenser) 113, and the blower fan 116 for the heat exchanger is provided for the heat exchanger (evaporator) 115. DC power supply 1 for rectifying AC voltage from AC power supply 1
01 supplies a DC voltage to the inverter 102. The inverter 102 supplies a sine wave AC voltage to the linear compressor 103 according to a control command from the inverter control means 108. The supply of the AC voltage from the inverter 102 causes the piston of the linear compressor 103 to reciprocate, and the refrigerant is sucked and compressed. Discharge temperature detection means 126
Detects the discharge temperature of the compressed and discharged refrigerant gas. The discharge temperature data detected by the discharge temperature detecting means 126 is sent to the motor constant auto-tuning means 109 and converted into the current magnet temperature of the linear motor. In addition, the signal from the induced voltage detection unit 105 of the linear motor is detected by the induced voltage detection unit 104, and the motor current is detected by the current detection unit 106 from the signal of the current detection unit 107 that detects the current of the linear motor. Then, a thrust constant is calculated from the converted magnet temperature, the detected induced voltage, and the current of the linear motor, and the calculated thrust constant data is preset in the data table. Then, the position of the piston is calculated from the thrust constant, the current and voltage of the linear motor, and the motor constant, and the protection drive control is performed, whereby more reliable drive control can be performed.

FIG. 10 is a characteristic diagram showing the relationship between the magnet surface temperature and the thrust constant. The thrust constant of the linear motor decreases as the magnet surface temperature rises. The engine 11
The engine speed detection means (external forced vibration detection means) 110 detects the engine speed of 1 and when the engine speed reaches the resonance frequency of the linear compressor 103, a control command from the inverter control means 108 to the inverter 102 is issued. Stop and put the motor in a free run state. When the piston repeatedly swings in this state, an induced voltage is generated at the terminals of the linear motor. The signal from the induced voltage detector 105 of the linear motor is detected by the induced voltage detecting means 104, the thrust constant is calculated from at least the detected induced voltage information, and the data table is preset to optimize the thrust constant on a regular basis. Can be converted.

Another embodiment of the present invention will be described with reference to FIGS. FIG. 11 is a block diagram showing the configuration of this embodiment. In the case of a vehicle compressor, a linear compressor 1
03 is attached to the engine 111 mount,
When the frequency of the forced vibration from the engine 111 becomes the same as the resonance frequency of the mechanical system (spring mass system) of the linear compressor 103, the movable part (piston) of the linear compressor 103.
However, it is driven by the force of the external vibration source.

FIG. 12 is a characteristic diagram showing the relationship between the vibration frequency of the external vibration and the engine speed. As shown in this characteristic diagram, the vibration frequency increases as the engine speed increases. Therefore, as in the configuration of FIG. 11, when the engine speed of the engine 111 is detected by the engine speed detection means (external forced vibration detection means) 110 and the engine speed becomes the resonance frequency of the linear compressor 103, inverter control is performed. Inverter 102 from means 108
Stops the control command for and sets the motor to the free-run state. When the piston repeatedly swings in this state, an induced voltage is generated at the terminals of the linear motor. The signal from the induced voltage detector 105 of the linear motor is detected by the induced voltage detecting means 104, the thrust constant is calculated from at least the detected induced voltage information, and the data table is preset to optimize the thrust constant on a regular basis. Can be converted. The thrust constant may be the current of the linear motor detected by the current detection unit 106 by inputting the signal from the current detection unit 107.

Another embodiment of the present invention is shown in FIGS.
This will be described with reference to FIG. FIG. 13 is a block diagram showing the configuration of the control device of this embodiment. The applied voltage of the inverter 102 applied to the linear motor 103 is detected by the applied voltage detection means 119, and the motor current is detected by the current detection means 10.
Detect at 6. The phase detector 125 detects the phase difference between the applied voltage and the motor current from the applied voltage detected by the applied voltage detector 119 and the motor current detected by the current detector 106. The inverter control means 108 is a drive frequency determining means 1 which always sets the drive frequency to the mechanical system resonance frequency.
21 and the command value determined by the target current determining means 122 for controlling the piston capacity, the inverter 102.
Is being controlled. For example, when the vibration frequency of the external forced vibration of the engine or the like matches the resonance frequency of the linear compressor 103, the movable portion (piston) of the linear compressor 103 has a piston stroke proportional to the external vibration force. extend. When the piston stroke due to external forced vibration becomes larger than the piston stroke determined by the command current, the linear motor becomes a generator and the DC power supply 101
Regenerative current flows to the side.

FIG. 14 is a characteristic diagram showing the phase states of the applied voltage and the motor current during normal operation and when external forced vibration is applied. When regenerative current flows, as shown in Fig. 14,
The phase of the motor current greatly advances with respect to the applied voltage.
From this relationship, by detecting the applied voltage and the phase of the motor current with the phase detection means 125, it is possible to detect that the external forced vibration is synchronized with the resonance frequency of the mechanical system and that the piston is assisted and vibrated. That is, in this case, the phase detection means 125 functions as an external forced vibration detection means. When the thrust constant needs to be preset, the mode immediately shifts to the auto tuning mode and the inverter 102 stops the drive control. Even after the drive control is stopped, the movable portion (piston) of the linear compressor 103 continues the amplitude motion by the external excitation force, so that the induced voltage is generated between the terminals of the linear motor. The induced voltage is detected by the induced voltage detecting means 104. Further, since the detected induced voltage changes at least approximately in proportion to the frequency of the movable part and the stroke amount of the piston, the piston position calculation means 123 and the induced voltage detection means 104 cause the stroke amount and frequency of the piston and the induction at that time. Based on the voltage information, the induced voltage, which is a reference for calculating the thrust constant, can be accurately calculated. Thrust constant of linear motor (torque generated per unit current)
Since a relational expression having at least a reference induced voltage as a function is established, when the induced voltage decreases, the thrust constant also decreases according to the functional expression. Therefore, by accurately calculating the reference induced voltage, the thrust constant of the linear motor can be calculated with high accuracy, and the calculated thrust constant is preset in the data table to end this mode. When the preset is completed, the inverter control means 108
Thus, the linear compressor 103 is switched to the normal operation mode, and the drive frequency determining means 121 and the target current determining means 1
Drive control of the linear compressor 103 is performed based on the command value of 22. In this way, the external excitation force is applied to the phase detection means 125.
By detecting with, it is possible to calculate and preset the thrust constant of the linear motor without apparently stopping the linear compressor 103.

FIG. 15 is a flowchart of the control device according to this embodiment. For example, if it is set to preset the thrust constant in the motor constant auto-tuning mode once a month, step 320 is performed once a month.
Enter the subroutine. Normal operating mode (Step 3
In step 21), drive control of the linear compressor is performed, and step 3
At 22, the motor applied voltage, current, and piston position are detected. Then, in step 323, the phase difference between the voltage applied to the motor and the current is calculated. The calculated phase difference is calculated in step 324.
If the phase difference is larger than the set value, the command current is stopped in step 325 to put the linear motor in the free-run state. The movable part of the linear motor continues to vibrate due to an external vibration force, and an induced voltage is generated at the terminals of the motor. In step 326, the induced voltage generated is measured. In step 327, the induced voltage under the reference condition is calculated from the detected stroke, frequency and induced voltage. Since the thrust constant of the linear motor is expressed by a function of the induced voltage, in step 328, the thrust constant is calculated from the induced voltage calculated under the reference condition. And step 3
At 29, the thrust constant is preset in the data table, and the normal linear compressor drive control is resumed.

Another embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the applied voltage of the linear motor is compared with the induced voltage calculated at that time, and when the calculated induced voltage is higher than the applied voltage, the mode is shifted to the induced voltage detection mode for detecting the forced vibration from the outside. is there. Therefore, in the present embodiment, although not shown in the figure, a comparison means for comparing the applied voltage of the linear motor and the induced voltage calculated at that time, and an external force for judging that the forced vibration from the outside when the calculated induced voltage is higher than the applied voltage. Vibration detection means. FIG. 16 is a characteristic diagram showing the relationship between the applied voltage and the induced voltage when the linear motor is in the normal operation state, and FIG. 17 is
It is a characteristic view which shows the relationship between the applied voltage and the induced voltage when the forced vibration from the outside matches the resonance frequency of the mechanical system and assists the piston. When the assist force acts on the piston from the outside, the induced voltage becomes higher than the applied voltage. Therefore, when it is detected that the induced voltage is higher than the applied voltage, the process proceeds to the induced voltage measuring means to calculate the thrust constant. According to this method, since no special sensor is used, it can be realized at a lower cost. In the above embodiment or separately from the above embodiment, before shipment from the factory of the drive unit for the linear compressor, at least the motor constant including the thrust constant is calculated based on the information from the induced voltage detecting means. It is preferable to preset in the data table of the flash memory of the microcomputer. This type of presetting means is provided, and at least after the linear compressor is assembled, the presetting means presets the motor constants in the memory, so that even if the motor specifications differ between different models or if there are large variations in the mass production of magnets, the same Drive control is possible with the program.

The relationship between the thrust constant and the position of the piston described in the above embodiment will be described. FIG. 18 is a characteristic diagram showing the thrust constant of the linear motor with respect to the amplitude center position of the movable portion (piston) of the linear compressor. In the figure,
The position "0" of the piston indicates when the center of the movable part of the linear motor and the center of the fixed part with the winding are relatively aligned, and the direction in which the movable part is offset to the compression side of the piston is "+". , "-" Indicates the direction of offset to the suction side.
Since the linear compressor does not have a crank mechanism, the amplitude center of the piston changes depending on the balance between suction pressure and discharge pressure. That is, the thrust constant also changes as shown in the figure according to the load condition.

Next, the iron loss generated in the linear motor will be described. FIG. 19 is a characteristic diagram showing the iron loss with respect to the frequency of the linear motor. As the frequency increases, the iron loss also increases in proportion to the square. When the iron loss increases, the thrust constant also changes. FIG. 20 is a characteristic diagram showing iron loss with respect to the motor current flowing in the linear motor. When the current increases, the field iron loss increases and the thrust constant decreases.

[0034]

As described above, according to the present invention, the motor constants are preset at regular intervals and the linear motors are drive-controlled based on the preset values, whereby variations in mass production of magnets of the linear motors, deterioration over time, demagnetization, It is possible to perform highly reliable drive control of the linear compressor in response to changes in the thrust constant of the linear motor based on temperature characteristics and piston position. Further, according to the present invention, the linear compressor is driven by the inverter, and the thrust constant of the motor is calculated from the induced voltage of the linear motor. Therefore, the thrust constant of the linear motor is calculated at the time of mass production or according to a regular schedule. Can be preset. Further, according to the present invention, when mounted on an automobile or the like and fastened to a vibration source of external vibration such as an engine, it is detected that the movable portion of the linear motor is reciprocating due to forced vibration from the vibration source. Since the induced voltage of the linear motor is measured by the induced voltage detection means and the thrust constant is calculated from the induced voltage, it is not necessary to forcibly drive the linear motor with the inverter, so the thrust constant of the linear motor is preset efficiently. can do. Further, according to the present invention, based on the stroke information of the piston and the amplitude center position information, at least the thrust constant of the linear motor is calculated by the auto-tuning means, so that the piston amplitude center, stroke amount, motor current, etc. can be varied. The thrust constant of the motor can be preset even under various operating conditions. Especially, when the top dead center of the piston is calculated using the thrust constant and collision prevention control is performed, the detection accuracy is improved and the linear compressor drive is more reliable. You can control. Further, according to the present invention, when mounted on an automobile or the like, and when there is a vibration source of external vibration such as an engine, the engine speed is detected,
In the preset mode, that is, the induced voltage of the linear motor is measured, the thrust constant is calculated, and presetting is possible.
Further, according to the present invention, a discharge temperature detecting means for detecting the discharge temperature of the refrigerant of the linear compressor is provided, the temperature of the magnet fixed to the movable part of the linear motor is converted from the discharge temperature, and the converted magnet temperature Therefore, by calculating and presetting the thrust constant, the thrust constant can be corrected by the temperature characteristics under any operating condition, and more reliable drive control of the linear compressor can be performed. Further, according to the present invention, the phase of the applied voltage of the linear motor and the phase of the motor current are detected, and when the phase difference is equal to or more than the set value, the mode is shifted to the auto tuning mode. The piston position and driving frequency are detected by the piston position detecting means, and the induced voltage at that time is detected by the induced voltage detecting means. Since the induced voltage is largely related to at least the driving frequency and the stroke of the piston, the calculated value is recalculated from the piston stroke and frequency to the standard measurement condition, so the induced voltage can be converted with high accuracy, resulting in the thrust of the linear motor. The constant can be calculated with high accuracy. Furthermore, when the motor thrust constant is preset and the motor constant auto-tuning mode ends, the normal drive control is immediately resumed, and the piston reciprocates continuously, so there is no sudden drop in performance and comfort is maintained. Does not spoil. Further, according to the present invention, when mounted on an automobile or the like and a vibration source for external vibration such as an engine is present, a means for detecting forced vibration from the vibration source is used to compare the applied voltage and the induced voltage of the linear motor. When the induced voltage is higher, the preset mode, that is, the induced voltage of the linear motor is measured, and the thrust constant is calculated and preset. Therefore, no sensor is required, which is less expensive and more reliable. Further, according to the present invention, when the linear compressor is mass-produced, the control program of the linear compressor is the same even if the motor specifications are different due to variations in magnet characteristics and model development, and the motor thrust constant is stored in the flash memory of the microcomputer. By presetting, it is possible to develop models with the same microcomputer and reduce mass production costs.

[Brief description of drawings]

FIG. 1 is a sectional view showing the configuration of a linear compressor.

FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 3 is a block diagram showing the configuration of another embodiment.

FIG. 4 is a control flow of an automatic tuning means for a thrust constant according to an embodiment of the present invention.

FIG. 5 is a diagram showing a relationship of an induced voltage of the linear motor with respect to an amplitude amount of a movable portion (piston) of the linear motor.

FIG. 6 is a block diagram showing a configuration of a control device according to another embodiment of the present invention.

FIG. 7 is a control flowchart of this embodiment.

FIG. 8 is a control block diagram according to another embodiment of the present invention.

FIG. 9 is a control block diagram according to still another embodiment of the present invention.

FIG. 10 is a characteristic diagram showing the relationship between magnet surface temperature and thrust constant.

FIG. 11 is a control block diagram according to still another embodiment of the present invention.

FIG. 12 is a characteristic diagram showing the relationship between the engine rotation speed and the excitation frequency of external vibration.

FIG. 13 is a control block diagram according to still another embodiment of the present invention.

FIG. 14 is a characteristic diagram showing phase states of applied voltage and motor current during normal operation and when external forced vibration is applied.

FIG. 15 is a flowchart of the control device according to the present embodiment.

FIG. 16 is a characteristic diagram showing the relationship between applied voltage and induced voltage when the linear motor is in a normal operation state.

FIG. 17 is a characteristic diagram showing the relationship between the applied voltage and the induced voltage when the forced vibration from the outside matches the resonance frequency of the mechanical system and assists the piston.

FIG. 18 is a characteristic diagram showing the thrust constant of the linear motor with respect to the amplitude center position of the movable part (piston) of the linear compressor.

FIG. 19 is a characteristic diagram showing iron loss with respect to frequency of a linear motor.

FIG. 20 is a characteristic diagram showing iron loss with respect to a motor current flowing through a linear motor.

FIG. 21 is a block diagram showing a conventional configuration.

FIG. 22 is a flowchart with a conventional configuration.

[Explanation of symbols]

100 AC power supply 101 DC power supply 102 Inverter 103 Linear compressor 104 Induced voltage detection means 106 Current detection means 108 Inverter control means 109 Motor constant auto tuning means 110 Engine speed detection means (external forced vibration detection means) 111 Engine 113 Heat exchanger (Condenser) 115 Heat exchanger (evaporator) 117 Electric expansion valve 118 Four-way valve 119 Applied voltage detection means 120 Electric power detection means 121 Drive frequency determination means 122 Target current determination means 123 Piston position calculation means 124 Preset means 201 Discharge chamber 202 Fixed part 203 Winding 204 Movable part 205 Elastic body 206 Compression chamber 207 Piston 208 Piston rod 209 Cylinder 210 Discharge temperature detection means

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 3H045 AA03 AA09 AA12 AA27 BA31                       BA41 CA09 CA21 DA07 DA46                       EA17 EA20 EA26 EA38 EA42                 3H076 AA02 BB28 BB43 CC07                 5H540 AA10 BA10 EE08 FA06 FB05                       FC02 FC03

Claims (9)

[Claims] 1. A control device for a linear compressor, which drives a piston in a cylinder by a linear motor to generate compressed gas, wherein the inverter outputs an alternating current supplied to the linear motor, and the linear motor flows into the linear motor. Target current determining means for determining a current, power detecting means for detecting the input power to the linear motor, drive frequency determining means for adjusting the frequency of the alternating current and determining a drive frequency, and target current determining means An inverter control means for instructing the inverter to create a current waveform corresponding to the current value command and the drive frequency from the drive frequency determining means, and an auto tuning means for presetting a parameter of a motor constant of the linear motor are provided. A control device for a linear compressor, which is characterized in that 2. An inverter for outputting an alternating current supplied to a linear motor, a target current determining means for determining a current flowing through the linear motor, a power detecting means for detecting an input power to the linear motor, and an alternating current. Driving frequency determining means for adjusting the frequency and determining the driving frequency, and commanding the inverter to create a current value command from the target current determining means and a current waveform corresponding to the driving frequency from the driving frequency determining means. Inverter control means, auto-tuning means for presetting the motor constant parameters of the linear motor, and induced voltage detection means for detecting the induced voltage of the linear motor are provided, and a specific AC current is applied to the linear motor by the inverter. After energizing to drive the movable part of the linear motor, stop energizing the inverter, When the movable part of the linear motor is in the free running state, the induced voltage of the linear motor is measured by the induced voltage detecting means, and the thrust constant calculated from at least the induced voltage is preset by the auto tuning means. A method for controlling a linear compressor, characterized by: 3. An inverter for outputting an alternating current supplied to a linear motor, a target current determining means for determining a current flowing through the linear motor, a power detecting means for detecting an input power to the linear motor, and an alternating current. Driving frequency determining means for adjusting the frequency and determining the driving frequency, and commanding the inverter to create a current value command from the target current determining means and a current waveform corresponding to the driving frequency from the driving frequency determining means. Inverter control means, auto-tuning means for presetting the parameter of the motor constant of the linear motor, induced voltage detection means for detecting the induced voltage of the linear motor, and the movable part of the linear motor reciprocates due to external forced vibration. An external forced vibration detecting means for detecting that the external forced vibration is detected, After the means detects the forced vibration from the outside, the induced voltage of the linear motor is measured by the induced voltage detecting means, and the thrust constant calculated from at least the induced voltage is preset by the auto tuning means. Characteristic linear compressor control method. 4. An inverter for outputting an alternating current supplied to a linear motor, a target current determining means for determining a current flowing through the linear motor, a power detecting means for detecting an input power to the linear motor, and an alternating current. Driving frequency determining means for adjusting the frequency and determining the driving frequency, and commanding the inverter to create a current value command from the target current determining means and a current waveform corresponding to the driving frequency from the driving frequency determining means. Inverter control means, auto-tuning means for presetting motor constant parameters of the linear motor, and piston position calculation means for calculating the stroke and top dead center position of the piston from at least the thrust constant of the linear motor are provided. Piston stroke and amplitude center position information calculated by the position calculation means On the basis of the above, at least the thrust constant of the linear motor is calculated and preset by the auto-tuning means, and the linear compressor control method is characterized. 5. An inverter for outputting an alternating current supplied to a linear motor, a target current determining means for determining a current flowing through the linear motor, a power detecting means for detecting an input power to the linear motor, and an alternating current. Driving frequency determining means for adjusting the frequency and determining the driving frequency, and commanding the inverter to create a current value command from the target current determining means and a current waveform corresponding to the driving frequency from the driving frequency determining means. Inverter control means, auto-tuning means for presetting motor constant parameters of the linear motor, induced voltage detection means for detecting the induced voltage of the linear motor, and engine speed detection for detecting external forced vibration from the engine speed. Means for detecting external forced vibration by the engine speed detecting means, When the energization of the inverter is stopped and the movable part of the linear motor is in the free-run state, the induced voltage of the linear motor is measured by the induced voltage detecting means, and at least the induced voltage is measured by the auto tuning means. A control method for a linear compressor, characterized in that the calculated thrust constant is preset. 6. The auto tuning having a discharge temperature detecting means for detecting a discharge temperature of a refrigerant of the linear compressor, converting the temperature of a magnet fixed to a movable portion of the linear motor from the discharge temperature, and performing the auto tuning. 6. The method of controlling a linear compressor according to claim 2, wherein the means corrects the thrust constant of the linear motor from the magnet temperature. 7. An inverter for outputting an alternating current supplied to a linear motor, a target current determining means for determining a current flowing through the linear motor, and a drive frequency determining means for adjusting a frequency of the alternating current to determine a drive frequency. , An inverter control means for instructing the inverter to create a current waveform corresponding to the current value command from the target current determination means and the drive frequency from the drive frequency determination means, and preset motor constant parameters of the linear motor Automatic tuning means, induced voltage detection means for detecting the induced voltage of the linear motor, applied voltage detection means for detecting the voltage applied to the linear motor, current detection means for detecting the current of the linear motor, Phase detecting means for detecting a phase difference between the detected applied voltage and the detected motor current; When the phase difference detected by the phase detection means is equal to or more than a set value, the auto-tuning means presets at least a thrust constant calculated from the induced voltage, and after presetting, the inverter is put into normal drive control. A method for controlling a linear compressor, which is characterized in that it is restored. 8. An inverter for outputting an alternating current supplied to a linear motor, a target current determining means for determining a current flowing through the linear motor, a power detecting means for detecting an input power to the linear motor, and an alternating current. Driving frequency determining means for adjusting the frequency and determining the driving frequency, and commanding the inverter to create a current value command from the target current determining means and a current waveform corresponding to the driving frequency from the driving frequency determining means. Inverter control means, auto tuning means for presetting motor constant parameters of the linear motor, induced voltage detection means for detecting induced voltage of the linear motor, and external forced vibration detection means for detecting forced vibration from the outside. And the external forced vibration detecting means is more than the applied voltage applied to the linear motor. When the induced voltage is high, it is determined to be external forced vibration, and after the external forced vibration detection means detects external forced vibration, the induced voltage detection means measures the induced voltage of the linear motor, A method of controlling a linear compressor, wherein at least a thrust constant calculated from the induced voltage is preset by the auto-tuning means. 9. A control device for a linear compressor, which drives a piston in a cylinder by a linear motor to generate compressed gas, wherein the inverter outputs an alternating current supplied to the linear motor and the linear motor flows. Target current determining means for determining a current, power detecting means for detecting the input power to the linear motor, drive frequency determining means for adjusting the frequency of the alternating current and determining a drive frequency, and target current determining means An inverter control means for instructing the inverter to create a current waveform corresponding to the current value command and the drive frequency from the drive frequency determining means; and a preset means for presetting a parameter of a motor constant of the linear motor, After assembling the linear compressor, calculate the motor constant including at least the thrust constant and A method for controlling a linear compressor, characterized in that the motor constant is stored in memory by means of a control means.