JP2001090661A - Device and method for controlling drive of linear compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive control device for linear motor for controlling the stroke of the linear motor while computing the maximum stroke of the linear motor. SOLUTION: A drive control unit 2 for a linear compressor 1 has a sensor signal processing circuit 6, a control circuit 5 and a motor driver 3. The control circuit 5 approximates the displacement of a piston to sine wave and while detects the overtime, during which the predetermined part of the piston exceeds the predetermined stroke. The maximum stroke is computed on the basis of the overtime and the approximated sine wave. The linear motor is controlled on the basis of the computed maximum stroke.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive control device and a drive control method for a linear compressor, and more particularly, to a drive control device for a linear compressor having a stroke calculator for calculating a maximum stroke in the linear compressor, and a drive for the linear compressor. It relates to a control method.

[0002]

2. Description of the Related Art In recent years, in a cooling device such as a refrigerator, as a device for compressing expanded refrigerant gas, a linear compressor that performs gas compression by reciprocating a piston in a cylinder by a linear motor has been developed. I have.

[0003] First, a linear compressor as a first related art will be described. In a linear compressor, the smaller the distance (top clearance) between the piston head and the upper wall of the cylinder when the piston reaches the top dead center, the higher the volumetric efficiency can be obtained. Next, control of the linear motor is performed.

In the control of the linear motor, the displacement of the piston is measured, and the top dead center of the piston is detected based on the measured value. Then, feedback control is performed so that the detected top dead center approaches the target value.

In order to measure the displacement of the piston, for example, a differential transformer is used. The differential transformer is a conversion element that converts a mechanical displacement into a voltage and a current corresponding to the displacement. Since this differential transformer is provided over the entire length of the piston stroke, it is excellent in that its displacement can be accurately detected.

However, since the differential transformer is expensive, there is a disadvantage that the cost is increased.

Therefore, there is a second conventional linear compressor which solves such a drawback. The sensor of this linear compressor includes a magnet disposed only at a certain predetermined position within the range of the stroke of the piston, and a proximity switch provided so that the switch is turned ON only when the magnet approaches in the reciprocating drive of the piston. Consists of

In such a linear compressor, the displacement of the piston is controlled by detecting that the magnet has passed a predetermined position within the range of the stroke.

[0009]

However, the linear compressor according to the second prior art has the following problems.

The proximity switch provided in the linear compressor can accurately detect that the magnet has passed, but cannot detect the magnitude of the stroke of the piston. As a result, the cooling capacity of the linear compressor could not be maximized.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and one object of the present invention is to provide a drive control device for a linear compressor capable of calculating the maximum stroke of a piston and feeding it back. It is another object of the present invention to provide such a drive control method.

[0012]

According to a first aspect of the present invention, there is provided a linear motor drive control device including a sensor unit, a stroke calculation unit, and a linear motor control unit.
The sensor unit detects that a predetermined portion of the piston unit connected to the linear motor has passed near a predetermined stroke position with respect to the stroke of the piston unit. The stroke calculation unit is electrically connected to the sensor unit and calculates a maximum stroke of the piston unit. The linear motor controller is
The linear motor is controlled according to the calculated maximum stroke. The stroke calculation unit approximates the displacement of the piston unit with a sine wave, detects an excess time in which a predetermined portion of the piston unit exceeds a predetermined stroke position, and, from the sine wave approximated based on the excess time, Calculate the maximum stroke of the piston.

According to this structure, even if the continuous displacement of the piston portion is not detected, the maximum stroke of the piston portion can be determined by the relationship between the excess time exceeding the predetermined stroke position and the approximated sine wave. Can be calculated. By controlling the drive of the piston based on the calculated maximum stroke, the capacity of the linear compressor can be maximized. In addition, a relatively inexpensive sensor can be used as the sensor, and the cost can be reduced.

The above-mentioned excess time (T) is determined by the time when a predetermined portion passes through a predetermined stroke position when the piston portion is driven toward one dead center, and the time when the piston portion passes through one dead center. When driving toward the other dead center, it is preferable that the difference be calculated as the difference from the time when the predetermined portion passes through the predetermined stroke position again. Further, the maximum stroke (Max_ST) is based on the excess time (T), the frequency (f) of the linear motor, and the size of the predetermined stroke position (Std_ST), and the following expression: Max_ST = Std_ST / sin (π / 2) −T · π
F) It is preferably calculated from: By approximating the displacement of the piston portion with a sine wave, the maximum stroke can be easily calculated by the above equation.

In a second aspect of the linear motor drive control device according to the present invention, a sensor unit, a stroke calculation unit,
A linear motor control unit. The sensor unit detects that a predetermined portion of the piston unit connected to the linear motor has passed near a predetermined stroke position with respect to the stroke of the piston unit. The stroke calculation unit is electrically connected to the sensor unit and calculates a maximum stroke of the piston unit. The linear motor control unit controls the linear motor according to the calculated maximum stroke. The stroke calculation unit obtains a vibration waveform based on at least an output voltage for driving the linear motor as a waveform corresponding to the displacement of the piston unit, and calculates a displacement of the vibration waveform corresponding to a predetermined stroke position and a maximum amplitude of the vibration waveform. The maximum stroke of the piston is calculated based on the calculated stroke.

According to this structure, the vibration waveform is obtained as a waveform corresponding to the displacement of the piston portion, and the displacement of the vibration waveform at a predetermined stroke position and the vibration waveform are determined without detecting the continuous displacement of the piston portion. The maximum stroke of the piston portion is calculated based on the relationship with the maximum amplitude. Moreover, since this vibration waveform is based on at least the output voltage of the linear motor, a more accurate maximum stroke can be calculated.

The above-mentioned vibration waveform is represented by the voltage of the linear motor,
Preferably, it is calculated by integrating the velocity waveform of the piston based on the current, coil resistance and inductance. Further, the maximum stroke is defined as a first time when a predetermined portion passes through a predetermined stroke position when the piston portion is driven toward one dead center, and when the piston portion passes through one dead center and passes through the other, When driving toward the dead center, a second time at which the predetermined portion passes through the predetermined stroke position is obtained again, and displacements at the first time and the second time are further obtained from the vibration waveform, It is preferable to calculate from the maximum amplitude in the vibration waveform based on the magnitude of the stroke position and its displacement. Thus, an accurate maximum stroke can be easily calculated.

[0018] More preferably, the stroke calculation section calculates the maximum stroke by further obtaining the deviation of the piston portion from the stroke center.

In this case, the maximum stroke can be calculated with higher accuracy by considering the deviation.

The above-mentioned sensor section preferably includes a magnet section provided at a predetermined portion of the piston section, and a magnetic detection section provided at a predetermined stroke position and detecting a magnetic field of the magnet section. .

In this case, it is possible to easily detect that a predetermined portion of the piston has passed near a predetermined stroke position by detecting the magnetic field of the magnet with the magnetic detector.

A first aspect of the linear motor drive control method according to the present invention includes the following steps. The sensor unit detects that a predetermined portion of the piston unit connected to the linear motor has passed near a predetermined stroke position with respect to the stroke of the piston unit. Approximate the displacement of the piston portion with a sine wave, detect the excess time when the predetermined part of the piston portion exceeds the predetermined stroke position, and calculate the maximum stroke of the piston portion from the approximated sine wave based on the excess time. calculate. The linear motor is controlled according to the calculated maximum stroke.

According to this method, the displacement of the piston portion is approximated by a sine wave, and the excess time exceeding the predetermined stroke position is obtained, thereby detecting the continuous displacement of the piston portion without detecting the continuous displacement of the piston portion. Can be easily calculated. Then, by controlling the linear motor in accordance with the calculated maximum stroke, the capability of the linear motor can be maximized.

A second aspect of the drive control method for a linear motor according to the present invention includes the following steps. The sensor unit detects that a predetermined portion of the piston unit connected to the linear motor has passed near a predetermined stroke position with respect to the stroke of the piston unit. A vibration waveform based on at least the output voltage for driving the linear motor is obtained as a waveform corresponding to the displacement of the piston portion, and the displacement of the vibration portion corresponding to the predetermined stroke position and the maximum amplitude of the vibration waveform of the piston portion are determined based on the maximum amplitude of the vibration waveform. Calculate the maximum stroke. The linear motor is controlled according to the calculated maximum stroke.

According to this method, a vibration waveform based on at least the output voltage of the linear motor is obtained as a waveform corresponding to the displacement of the piston portion, and without detecting the continuous displacement of the piston portion, the vibration at the predetermined stroke position can be obtained. Based on the relationship between the displacement of the vibration waveform and the maximum amplitude of the vibration waveform,
A more accurate maximum stroke of the piston can be easily calculated. Then, by controlling the linear motor in accordance with the calculated maximum stroke, it is possible to maximize the performance of the linear motor.

As described above, the sensor section includes a magnet section provided at a predetermined portion of the piston section, and a magnetic detection section provided at a predetermined stroke position and detecting a magnetic field of the magnet section. Is preferred.

[0027]

(Embodiment 1) First, the structure of a linear compressor according to Embodiment 1 of the present invention will be described. As shown in FIG. 1, in the linear compressor, cylinders 11a and 11b are provided at an upper end and a lower end of a cylindrical casing 10, respectively. In the cylinders 11a, 11b, pistons 12a,
12b are fitted respectively. Pistons 12a, 1
Compression chambers 13a and 13b are formed between the head of 2b and the upper walls of the cylinders 11a and 11b.

The cylinders 11a and 11b are provided with suction valves 14a and 14b and discharge valves 15a and 15b which open and close according to the gas pressure in the compression chambers 13a and 13b.

The pair of pistons 12a and 12b are connected to one end and the other end of one rod 16, respectively. The rod 16 has a pair of bearings 17a, 1
The casing 10 and the cylinders 11a and 11b are reciprocally supported by the coil 7b and the coil springs 18a and 18b.

The linear compressor has a linear motor 20 for reciprocatingly driving the pistons 12a and 12b.
Is provided. The linear motor 20 is a voice coil motor, and includes a yoke portion 10a and a permanent magnet 21.
, A fixed portion including a coil 23 and a cylindrical support member 2
And a movable part including the movable part 4. The yoke part 10a forms a part of the casing 10. The permanent magnet 21 is fixed to the inner peripheral wall of the yoke part 10a.

One end of the support member 24 is
1 is loosely inserted into a cylindrical space between the outer peripheral wall of the body 12 and the other end is connected to the center of the rod 16. The coil 23 is attached to one end of the support member 24 and faces the permanent magnet 21. For example, two magnets 42a and 42b are fixed to the arm 160 projecting from the center of the rod 16 with the stroke center interposed therebetween.

On the other hand, a magnetic detecting section 41 is attached to the projection 100 formed on the inner surface of the casing 10 so as to face the magnets 42a and 42b. The presence / absence detection sensor 4 is constituted by the magnetic detection unit 41 and the magnets 42a and 42b. In addition, 2
Although two magnets 42a and 42b are provided, only one magnet may be provided.

As the magnetic detector, a Hall element or M
An R element is desirable. Further, in addition to the above-described sensor using magnetism, a proximity sensor using eddy current may be used.

The above-described linear compressor has a resonance frequency determined by the masses of the pistons 12a and 12b, the rod 16, the coil 23 and the support member 24, the spring constant of the gas in the compression chambers 13a and 13b, the spring constant of the coil spring 18, and the like. are doing. This resonance frequency is usually set near the frequency of commercial power (for example, 60 Hz). By driving the linear motor 20 at this resonance frequency, the gas can be compressed alternately in the pair of compression chambers 13a and 13b.

Next, the above-described linear compressor includes:
As shown in FIG. 2, a drive control unit 2 including a motor driver 3, a control circuit 5, and a sensor signal processing circuit 6 is connected.

The sensor signal (presence / absence signal) output from the presence / absence detection sensor 4 according to the displacement of the piston of the linear compressor is input to the sensor signal processing circuit 6. This sensor signal is a signal indicating that the stroke of the linear compressor has exceeded a certain position (reference stroke). In the sensor signal processing circuit 6, position data Pa is created from this sensor signal. The position data Pa is sent to the control circuit 5.

In the control circuit 5, the input position data P
a, a control signal φc is generated, and the control signal φc
Is sent to the motor driver 3. In the motor driver 3, the output current is controlled according to the control signal φc, and the output current is supplied to the linear motor.

Next, FIG. 3 shows the configuration of the main part of the control circuit 5 in the drive control unit 2. As shown in FIG. 3, the control circuit 5 includes a current command value basic value generation unit 30, a current command value generation unit 31, a current gain control unit 34, and an amplitude neutral position control unit 3.
5. Top and bottom dead center detection unit 32, current / position phase difference detection unit 33
And a frequency control unit 36.

The current command value basic value generator 30 generates a current command value basic value. The current command value basic value is sent to the current command value generator 31.

The current command value generator 31 generates a current command value based on the current command value basic value generated by the current command value basic value generator 30 and the current gain. further,
The current command value is converted into control signal φc and output to motor driver 3.

The upper and lower dead center detector 32 generates timing data of the maximum displacement (maximum stroke) of the piston based on the position data Pa from the sensor signal processing circuit 6 (hereinafter referred to as "timing data"). Is done. Further, as will be described later, a top dead center side amplitude between the top dead center of the piston and the origin and a bottom dead center side amplitude between the bottom dead center and the origin are detected. As shown in FIG. 8, detection of the top dead center side amplitude and the bottom dead center side amplitude is performed, for example, every time the current command value 1 reciprocating vibration passes near the maximum value.

The current / position phase difference detector 33 detects a phase difference between the timing data generated by the upper and lower dead center detector 32 and the current command value generated by the current command value generator 31. As shown in FIG. 8, the detection of the phase difference is performed, for example, each time the current command value 1 reciprocating vibration passes near the minimum value.

The current gain control unit 34 compares the top dead center side amplitude and the bottom dead center side amplitude detected by the top and bottom dead center detection unit, and determines which of the top dead center side amplitude and the bottom dead center side amplitude is larger. The current gain value used in the current command value generation unit 31 is set at each cycle of the reciprocating drive of the piston such that the current value is the maximum amplitude current value and the maximum amplitude current value matches the preset maximum amplitude target value. Is controlled.

The amplitude neutral position control unit 35 compares the top dead center side amplitude and the bottom dead center side amplitude detected by the top and bottom dead center detection unit 32, and calculates the difference between the top dead center side amplitude and the bottom dead center side amplitude. Is controlled each time one cycle of the current command value basic value is completed, so that the shift amount is reduced.

That is, in the amplitude neutral position control unit 35,
If the top dead center side amplitude is larger than the bottom dead center side amplitude, the shift amount is corrected to the negative side (downward), and the top dead center side amplitude is larger than the bottom dead center side amplitude. If smaller, the shift amount is corrected to the positive side (upward).

The frequency controller 36 determines whether or not the phase difference detected by the current / position phase difference detector 33 exceeds a preset allowable value. If the phase difference exceeds the allowable value, the angular frequency used in the current command value basic value generator 30 is corrected so that the phase difference disappears.

As shown in FIG. 8, the phase difference is, for example,
Control is performed so that the timing at which the current command value passes through the zero cross point substantially coincides with the timing at which the position of the piston reaches the maximum stroke. The timing at which the position of the piston reaches the maximum stroke is, as shown in the figure, to add a half of the time T (excess time) exceeding the reference stroke position to the time when the presence / absence detection sensor 4 is turned on. Is estimated.

Next, the operation of the control circuit 5 will be described with reference to the flowcharts shown in FIGS.

First, a basic current command value generator 30 generates a basic current command value. Current command value generator 3
At 1, a control signal φc is generated. When a current is supplied from the motor driver 3 to the coil of the linear motor, the movable portion of the linear motor starts reciprocating drive, and gas is compressed.

When the drive section of the linear motor starts reciprocating drive, a sensor signal from the presence / absence detection sensor 4 is sent to the sensor signal processing circuit 6.

In step S1, the sensor signal processing circuit 6
Reading of data from is performed.

In step S 2, based on the current command value basic value generated by the current command value basic value generator 30 and the current gain generated by the current gain controller 34,
The current command value is calculated in the current command value generation unit 31.

In step S3, current command data corresponding to the calculated current command value, that is, a control signal φc is output to the motor driver 3.

In step S4, the basic current command value generator 30 generates a basic current command value based on the position correction amount and the frequency set value.

In step S5, it is determined whether or not the current command value 1 reciprocating vibration has passed, for example, near the maximum value.
That is, it is determined whether the current command value 1 reciprocating vibration has ended. If it is not determined in step S5 that the current command value 1 reciprocating vibration has ended, the process proceeds to step S5.
Jump to 19.

On the other hand, if it is determined that the current command value 1 reciprocating vibration has been completed, the process proceeds to steps S6 to S11.
The top dead center side amplitude and the bottom dead center side amplitude of the piston are calculated by the top and bottom dead center detection unit 32.

Here, the calculation procedure will be described in detail. Assuming that the displacement of the piston is a sine wave, the displacement of the piston will draw a sine wave having a constant frequency as shown in FIG. At this time, when the time exceeding the reference stroke is T, the angle on the circular coordinates corresponding to the time T is θ, and the angle θ ′ is as shown in the figure, θ ′ is given by the following equation.

Θ ′ = π / 2−θ / 2 The sine of the angle θ ′ is given by the following equation.

Sin θ ′ = Std_ST / Max_ST Further, the time T is given by the following equation, where the frequency is Freq.

T = θ / (2 · π · Freq) From this, the maximum stroke Max_ST is given by the following equation.

Max_ST = Std_ST / sin (π
/ 2−T · π · Freq) In this manner, the maximum stroke Ma is obtained by the reference stroke Std_ST, the excess time T, and the frequency Freq.
x_ST is calculated.

Note that the excess time T is more specifically obtained as follows. That is, for example, on the top dead center side, when the piston is driven toward the top dead center, the magnets 42a and 42b provided at predetermined portions are driven by a clock (not shown) built in the drive control unit 2. Time t1 when the magnet passes through the vicinity of the magnetic detection unit 41 and time t2 when the magnets 42a and 42b pass again near the magnetism detection unit 41 when the piston drives toward the bottom dead center via the top dead center. Detected, and the difference is obtained as (t2−t1). The same applies to the bottom dead center side. This processing is desirably performed, for example, by the sensor signal processing circuit 6.

Although FIG. 9 shows the maximum stroke on the top dead center side, the maximum stroke on the bottom dead center side can be calculated in the same manner as the maximum stroke on the top dead center side.

Therefore, first, in step S6, it is determined whether or not the count value on the top dead center side has exceeded zero. The count value is incremented while the predetermined portion of the piston exceeds the reference stroke on the top dead center side and the bottom dead center side, and is set to 0 while the predetermined portion does not exceed the reference stroke.

If it is determined that the count value on the top dead center side does not exceed 0, the process proceeds to step S7. In step S7, the top dead center reference stroke is set to the maximum stroke (top dead center side amplitude).

On the other hand, if it is determined that the count value on the top dead center side has exceeded 0, the flow proceeds to step S8. In step S8, the displacement (maximum stroke) at the top dead center is calculated by the above-described calculation procedure.

Next, in step S9, it is determined whether or not the count value on the bottom dead center side has exceeded zero. When it is determined that the count value on the bottom dead center side does not exceed 0, the process proceeds to step S10. In step S10, the bottom dead center side reference stroke is set to the minimum stroke (bottom dead center side amplitude).

On the other hand, if it is determined that the count value on the bottom dead center side has exceeded 0, the process proceeds to step S11. In step S11, the displacement (minimum stroke) at the bottom dead center is calculated by the above-described calculation procedure.

In step S12, the magnitude relation between the top dead center side amplitude and the bottom dead center side amplitude is compared. At this time, if the top dead center side amplitude is larger than the bottom dead center side amplitude, the process proceeds to step S13.

In step S13, the amplitude neutral position control unit 35 sets a negative correction amount as a shift amount correction amount.

In the next step S14, the top dead center side amplitude is set as the maximum amplitude. On the other hand, if the top dead center side amplitude is smaller than the bottom dead center side amplitude in step S12, the process proceeds to step S15.

In step S15, the amplitude neutral position control unit 35 sets a positive correction amount as the shift amount correction amount.

In the next step S16, the bottom dead center side amplitude is set as the maximum amplitude. In step S17, the current gain control section 34 controls and sets the current gain so that the maximum amplitude matches the target amplitude.

In the next step S18, the counter at the top dead center is reset and the counter at the bottom dead center is reset.

In the next step S19, it is determined whether or not the displacement of the piston exceeds the top dead center side reference stroke. If it is determined that the displacement of the piston exceeds the top dead center side reference stroke, the process proceeds to step S20,
The top dead center counter is incremented.

On the other hand, if it is determined in step S19 that the displacement of the piston has not exceeded the top dead center reference stroke, the process proceeds to step S21 without executing step S20.

In step S21, it is determined whether or not the displacement of the piston exceeds the lower dead center side reference stroke. When it is determined that the displacement of the piston exceeds the bottom dead center side reference stroke, the process proceeds to step S22, and the bottom dead center side counter is incremented.

On the other hand, if it is determined in step S21 that the displacement of the piston has not exceeded the top dead center side reference stroke, the process proceeds to step S23 without executing step S22.

In step S23, it is determined whether or not the current command value 1 reciprocating vibration has passed, for example, near the minimum value. That is, it is determined whether the current command value 1 reciprocating vibration has ended. If it is not determined that the current command value 1 reciprocating vibration has ended, the process jumps to step S30.

On the other hand, if it is determined in step S23 that the current command value 1 reciprocating vibration has been completed, the process proceeds to step S24.

In step S24, the current / position phase difference detector 33 detects the phase difference between the current command value and the timing data.

In the next step S25, the count value of the phase control is incremented. In step S26,
It is determined whether the count value of the phase control has reached the set value. If it is not determined that the count value of the phase control has reached the set value, the process jumps to step S30.

On the other hand, if it is determined in step S26 that the count value of the phase control has reached the set value, the process proceeds to step S27.

In step S27, it is determined whether or not the phase difference between the current command value and the timing data is within a range of an allowable value. If it is determined that the phase difference between the current command value and the timing data is not within the range of the allowable value, step S2
Proceed to 8.

In step S28, the frequency control unit 36 corrects the angular frequency used in the current command value basic value generation unit 30 so that the phase difference is eliminated.

On the other hand, if it is determined in step S27 that the phase difference between the current command value and the timing data is within the range of the allowable value, the process proceeds to step S29 without executing step S28.

In step S29, the count value of the phase control is reset. In the next step S30, it is determined whether to end the control procedure. If the control procedure ends, the procedure ends.

On the other hand, if the control procedure is not to be ended in step S30, the procedure returns to step S1, and the same procedure is repeated.

The linear compressor according to the present embodiment operates as described above. According to this linear compressor, the displacement of the piston is approximated by a sine wave, the excess time exceeding the predetermined stroke position is detected, and the maximum stroke of the piston is calculated based on the relationship between the excess time and the sine wave. be able to. That is, the maximum stroke can be calculated without detecting the continuous displacement of the piston.

The stroke of the piston can be controlled based on the calculated maximum stroke. In particular,
By controlling the maximum stroke, the performance of the linear compressor can be maximized. Moreover, by using the relatively inexpensive presence / absence detection sensor 4 as a sensor, compared to the case of a conventional linear compressor,
Manufacturing costs can also be reduced.

(Embodiment 2) Next, a linear compressor according to Embodiment 2 of the present invention will be described.

In the present linear compressor, a vibration waveform of the linear motor is obtained as a waveform corresponding to the displacement of the piston, and a higher precision is obtained based on the displacement of the vibration waveform corresponding to the predetermined stroke position and the maximum amplitude of the vibration waveform. The maximum stroke can be determined.

That is, in addition to the presence / absence signal from the presence / absence detection sensor 4, a signal corresponding to the output voltage of the linear motor or the like is input to the control circuit. More specifically, as shown in FIG. 10, a motor driver 3, a control circuit 5, and a sensor signal processing circuit 6 connected to a linear compressor.
In addition to the position data Pa sent from the sensor signal processing circuit 6, a signal corresponding to the output voltage value and the like is sent from the motor driver 3 to the control circuit 5 in the drive control unit 2 composed of

The structure of the linear compressor itself is as follows.
Since the structure is the same as that of the linear compressor shown in FIG. 1 described above, the description is omitted.

Next, the configuration of the main part of the control circuit 5 in the drive control unit 2 is shown in FIG. As shown in FIG. 11, the control circuit 5 includes a current command value basic value generation unit 30, a current command value generation unit 31, a current gain control unit 34, an amplitude neutral position control unit 35, a vertical dead center detection unit 32, It comprises a position / phase difference detection unit 33 and a frequency control unit 36.

In particular, a signal corresponding to the output voltage value sent from the motor driver 3 is input to the upper and lower dead center detecting section 32. The other components are the same as those of the linear compressor according to the first embodiment, and a description thereof will be omitted.

Next, the operation of the control circuit 5 will be described with reference to FIGS.
This will be described according to the flowchart shown in FIG.

First, similarly to the first embodiment, a basic current command value generation unit 30 generates a basic current command value, and a current command value generation unit 31 generates a control signal φc. A current is supplied from the motor driver 3 to the coil of the linear motor, and the movable portion of the linear motor starts reciprocating drive.

In step S51, data is read from the sensor signal processing circuit 6. Next Step 5
In step 2, the signal corresponding to the output voltage value from the motor driver 3 is read in the upper and lower dead center detector 32.

In step S53, based on the current command value basic value generated by the current command value basic value generator 30 and the current gain generated by the current gain controller 34, the current command value generator 31 A value is calculated.

In step S54, current command data corresponding to the calculated current command value, that is, a control signal φc is output to the motor driver 3.

In step S55, the current command value basic value generator 30 generates a current command value basic value based on the position correction amount and the frequency set value.

In step S56, it is determined whether or not the current command value 1 reciprocating vibration has passed, for example, near the maximum value. That is, it is determined whether the current command value 1 reciprocating vibration has ended. If it is not determined that the current command value 1 reciprocating vibration has ended, the process jumps to step S74.

On the other hand, if it is determined in step S56 that the current command value 1 reciprocating vibration has ended, the process proceeds to step S57.

In step S57, based on the signal corresponding to the voltage value of the linear motor and the current command value holding value,
A fluctuation waveform of the piston speed is calculated.

More specifically, it is calculated as follows. From the voltage E, current i, thrust constant K, inductance L and coil resistance R of the linear motor, the piston speed dx / dt of the linear motor is expressed by the following equation. In addition, the values of the thrust constant K, the inductance L, and the coil resistance R are pre-installed values. dx / dt = 1 / K ・ (EL-di / dt-Ri) Next, in step S58, a fluctuation waveform shape of the piston position is calculated based on the fluctuation waveform of the piston speed. That is, by integrating the above equation, the fluctuation waveform f (t) of the piston position is given by the following equation, and draws a waveform close to a sine wave as shown in FIG. f (t) = ∫dx / dt · dt At this time, the absolute value of the maximum amplitude of f (t) is 1.

Next, at step S59, the magnitude (magnification a) and the neutral deviation (deviation b) of the actual piston position fluctuation waveform are estimated. That is, with respect to the reference stroke Std_ST, the magnification a and the deviation b satisfying the following equation are obtained. af (t1) + b = af (t1 + Tu) + b af (t3) + b = af (t3 + Tl) + b In step S60, it is determined whether or not the count value on the top dead center side has exceeded zero. If it is determined that the count value on the top dead center side does not exceed 0, step S
Go to 61. In step S61, the top dead center side reference stroke is set to the maximum stroke (top dead center side amplitude).

On the other hand, if it is determined in step S60 that the count value on the top dead center side has exceeded 0,
Proceed to step S62. In step S62, the displacement (maximum stroke) at the top dead center is calculated. The maximum stroke (Max_ST) is expressed by the following equation. Max_ST = af (t) max−b Next, in step S63, it is determined whether or not the count value on the bottom dead center side exceeds 0. When it is determined that the count value on the bottom dead center side does not exceed 0, the process proceeds to step S64. In step S64, the bottom dead center reference stroke is set to the minimum stroke (bottom dead center amplitude).

On the other hand, if it is determined in step S63 that the count value on the bottom dead center side has exceeded 0,
Proceed to step S65. In step S65, the displacement (minimum stroke) at the bottom dead center is calculated. The minimum stroke (-Max_ST) is represented by the following equation. -Max_ST = -af (t) max + b In step S66, the magnitude relationship between the top dead center side amplitude and the bottom dead center side amplitude is compared. At this time, if the top dead center side amplitude is larger than the bottom dead center side amplitude, the process proceeds to step S67.

In step S67, the amplitude neutral position control unit 35 sets a negative correction amount as the shift amount correction amount.

In the next step S68, the top dead center side amplitude is set as the maximum amplitude. On the other hand, when the top dead center side amplitude is smaller than the bottom dead center side amplitude in step S66, the process proceeds to step S69.

In step S69, the amplitude neutral position control unit 35 sets a positive correction amount as the shift amount correction amount.

In the next step S70, the bottom dead center side amplitude is set as the maximum amplitude. In step S71, the current gain control section 34 controls and sets the current gain so that the maximum amplitude matches the target amplitude.

In the next step S72, the counter at the top dead center is reset and the counter at the bottom dead center is reset. In the next step S73, the signal corresponding to the output voltage value for one cycle and the held value of the current command value are deleted. In the next step S74, the signal corresponding to the output voltage value for one cycle and the current command value are sequentially held.

In the next step S75, it is determined whether or not the displacement of the piston exceeds the top dead center side reference stroke. When it is determined that the displacement of the piston exceeds the top dead center side reference stroke, the process proceeds to step S76,
The top dead center counter is incremented.

On the other hand, if it is determined in step S75 that the displacement of the piston has not exceeded the top dead center reference stroke, the process proceeds to step S77 without executing step S76.

In step S77, it is determined whether or not the displacement of the piston exceeds the lower dead center side reference stroke. When it is determined that the displacement of the piston exceeds the bottom dead center side reference stroke, the process proceeds to step S78, and the bottom dead center side counter is incremented.

On the other hand, if it is determined in step S77 that the displacement of the piston has not exceeded the top dead center reference stroke, the flow advances to step S79 without executing step S78.

In step S79, it is determined whether the current command value 1 reciprocating vibration has passed, for example, near the minimum value. That is, it is determined whether the current command value 1 reciprocating vibration has ended. If it is not determined that the current command value 1 reciprocating vibration has ended, the process jumps to step S86.

On the other hand, if it is determined in step S79 that the reciprocating vibration of the current command value 1 has been completed, the process proceeds to step S80.

In step S80, the current / position phase difference detector 33 detects the phase difference between the current command value and the timing data.

In the next step S81, the count value of the phase control is incremented. In step S82,
It is determined whether or not the phase control count value has reached the set value. If it is not determined that the count value of the phase control has reached the set value, the process jumps to step S86.

If it is determined in step S82 that the phase control count value has reached the set value, the flow advances to step S83.

In step S83, it is determined whether or not the phase difference between the current command value and the timing data is within a range of an allowable value. If it is determined that the phase difference between the current command value and the timing data is not within the range of the allowable value, step S8
Proceed to 4.

In step S84, the frequency controller 36 corrects the angular frequency used in the current command value basic value generator 30 so that the phase difference is eliminated.

On the other hand, if it is determined in step S83 that the phase difference between the current command value and the timing data is within the range of the allowable value, the process proceeds to step S85 without executing step S84.

In step S85, the count value of the phase control is reset. In the next step S86, it is determined whether to end the control procedure. If the control procedure ends, the procedure ends.

According to this linear compressor, a vibration waveform based on the output voltage of the linear motor is obtained as a waveform corresponding to the displacement of the piston, and the displacement of the vibration waveform at a predetermined stroke position and the maximum amplitude of the vibration waveform are determined. The maximum stroke of the piston portion is calculated based on the relationship. That is, the maximum stroke can be calculated without detecting the continuous displacement of the piston.

Furthermore, in this case, since the vibration waveform is based on at least the output voltage of the linear motor, a more accurate maximum stroke is calculated than the approximation of the displacement of the piston described in the first embodiment with a sine wave. be able to.

In this embodiment, the magnets are arranged at predetermined stroke positions with respect to the center of the stroke of the piston as a sensor, but the magnets may be arranged only at one of them. In that case,
By treating as if there is no deviation b, the maximum stroke can be obtained more easily.

In each embodiment, a two-piston type linear compressor is described as an example, but the present invention can be similarly applied to a one-piston type linear compressor.

Further, the apparatus or method for controlling the stroke of the linear motor described in each of the embodiments is not limited to the linear motor of the linear compressor, and can be widely applied to the stroke control of the linear motor.

The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[0134]

According to the first aspect of the drive control apparatus for a linear motor according to the present invention, the displacement of the piston is approximated by a sine wave without detecting the continuous displacement of the piston,
The maximum stroke of the piston portion can be calculated by calculating the excess time exceeding the predetermined stroke position. By controlling the drive of the piston based on the calculated maximum stroke, the capacity of the linear compressor can be maximized. In addition, a relatively inexpensive sensor can be used,
Cost can be reduced.

The above-mentioned excess time (T) is determined by the time when a predetermined portion passes through a predetermined stroke position when the piston portion is driven toward one dead center, and when the piston portion passes through one dead center. When driving toward the other dead center, it is preferable that the difference be detected as a difference from the time when the predetermined portion passes through the predetermined stroke position again. The maximum stroke (Max_ST) is obtained by approximating the displacement of the piston portion with a sine wave to obtain the excess time (T), the frequency of the linear motor (f), and the size of the predetermined stroke position (Std).
_ST), and the following equation: Max_ST = Std_ST / sin (π / 2−T · π
F) It is preferably calculated from:

According to the second aspect of the drive control apparatus for a linear motor according to the present invention, a vibration waveform is obtained as a waveform corresponding to the displacement of the piston without detecting the continuous displacement of the piston. Is calculated based on the displacement of the vibration waveform at the stroke position and the maximum amplitude of the vibration waveform. Moreover, since this vibration waveform is based on at least the output voltage of the linear motor, a more accurate maximum stroke can be calculated.

The above-mentioned vibration waveform is preferably calculated by integrating the velocity waveform of the piston portion based on the voltage of the linear motor and the like. The maximum stroke is
When the piston portion is driven toward one dead center, a displacement at a first time when a predetermined portion passes through a predetermined stroke position, and the piston portion passes through one dead center and moves toward the other dead center. When the actuator is driven, the displacement at the second time when the predetermined portion passes through the predetermined stroke position is obtained again, and is calculated based on the magnitude of the predetermined stroke position, the displacement thereof, and the maximum amplitude in the vibration waveform. Is preferred. Thus, an accurate maximum stroke can be easily calculated.

The stroke calculating section calculates the maximum stroke by further calculating the deviation from the stroke center of the piston section, so that a more accurate maximum stroke can be calculated.

The above-described sensor section includes a magnet section provided at a predetermined portion of the piston section and a magnetism detection section provided at a predetermined stroke position and detecting a magnetic field of the magnet section. By detecting the magnetic field of the magnet part by the magnetic detection part, it is possible to easily detect that a predetermined part of the piston part has passed near a predetermined stroke position.

According to the first aspect of the drive control method of the linear motor according to the present invention, the displacement of the piston is approximated by a sine wave, and the excess time exceeding the predetermined stroke position is determined. The maximum stroke of the piston portion can be easily calculated without detecting the continuous displacement of the piston. Then, by controlling the linear motor in accordance with the calculated maximum stroke, the capability of the linear motor can be maximized.

According to the second aspect of the linear motor drive control method according to the present invention, a vibration waveform based on at least the output voltage of the linear motor is obtained as a waveform corresponding to the displacement of the piston portion, and the vibration waveform at a predetermined stroke position is obtained. A more accurate maximum stroke of the piston portion can be easily calculated based on the displacement of the vibration waveform and the maximum amplitude of the vibration waveform without detecting continuous displacement of the piston portion. Then, by controlling the linear motor in accordance with the calculated maximum stroke, it is possible to maximize the performance of the linear motor.

As described above, the sensor section includes a magnet section provided at a predetermined portion of the piston section, and a magnetic detection section provided at a predetermined stroke position and detecting a magnetic field of the magnet section. Is preferred.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a linear compressor according to Embodiment 1 or 2 of the present invention.

FIG. 2 is a block diagram showing a configuration of a drive control device for the linear compressor according to the first embodiment.

FIG. 3 is a block diagram of a control circuit shown in FIG. 2 in the embodiment.

FIG. 4 is a first diagram of a flowchart showing an operation of the control circuit in the embodiment.

FIG. 5 is a second diagram of a flowchart showing the operation of the control circuit in the embodiment.

FIG. 6 is a third diagram of a flowchart showing the operation of the control circuit in the embodiment.

FIG. 7 is a fourth diagram of the flowchart showing the operation of the control circuit in the embodiment.

FIG. 8 is a first diagram showing a procedure for calculating a maximum stroke in the embodiment.

FIG. 9 is a second diagram showing a procedure for calculating a maximum stroke in the embodiment.

FIG. 10 is a block diagram showing a configuration of a drive control device for a linear compressor according to a second embodiment.

FIG. 11 is a block diagram of a control circuit shown in FIG. 10 in the embodiment.

FIG. 12 is a first diagram of a flowchart showing an operation of the control circuit in the embodiment.

FIG. 13 is a second diagram of the flowchart showing the operation of the control circuit in the embodiment.

FIG. 14 is a third diagram of a flowchart showing the operation of the control circuit in the embodiment.

FIG. 15 is a fourth diagram of the flowchart showing the operation of the control circuit in the embodiment.

FIG. 16 is a fifth diagram of the flowchart showing the operation of the control circuit in the embodiment.

FIG. 17 is a diagram showing a procedure for calculating a maximum stroke in the embodiment.

[Explanation of symbols]

1 linear compressor, 2 drive control device, 3 motor driver, 4 presence / absence detection sensor, 5 control circuit, 6
Sensor signal processing circuit, 30 current command value basic value generation unit,
31 current command value generator, 32 vertical dead center detector, 33
Current / position phase difference detector, 34 current gain controller,
35 Amplitude neutral position control unit, 36 Frequency control unit.

Claims (9)

[Claims] 1. A drive control device for a linear compressor having a linear motor, wherein a predetermined portion of a piston portion connected to the linear motor has passed near a predetermined stroke position with respect to a stroke of the piston portion. A stroke calculating unit that is electrically connected to the sensor unit and calculates a maximum stroke of the piston unit; and a linear motor that controls the linear motor according to the calculated maximum stroke. A control unit, wherein the stroke calculation unit approximates the displacement of the piston unit as a sine wave, detects an excess time in which a predetermined portion of the piston unit exceeds the predetermined stroke position, and detects the excess time. Calculating the maximum stroke of the piston portion from the sine wave approximated based on Motion control device. 2. The excess time (T) is determined when the piston portion is driven toward one dead center.
At the time when the predetermined portion passes through the predetermined stroke position, and when the piston portion passes through one dead center and drives toward the other dead center, the predetermined portion again moves to the predetermined stroke position. The maximum stroke (Max_ST) is detected as the difference from the time at which the linear motor passes through, and the frequency (f) of the linear motor.
And the size of the predetermined stroke position (Std_S
T), the following equation: Max_ST = Std_ST / sin (π / 2−T · π
The drive control device for a linear compressor according to claim 1, wherein the drive control device is calculated by: f). 3. A drive control device for a linear compressor having a linear motor, wherein a predetermined portion of a piston portion connected to the linear motor has passed near a predetermined stroke position with respect to a stroke of the piston portion. A stroke calculating unit that is electrically connected to the sensor unit and calculates a maximum stroke of the piston unit; and a linear motor that controls the linear motor according to the calculated maximum stroke. A control unit, wherein the stroke calculation unit obtains a vibration waveform based on at least an output voltage for driving the linear motor as a waveform corresponding to the displacement of the piston unit, and the vibration waveform corresponding to the predetermined stroke position The maximum stroke of the piston part is calculated based on the displacement of the piston and the maximum amplitude of the vibration waveform. To, the linear compressor driving control device. 4. The vibration waveform is calculated by integrating a velocity waveform of the piston based on a voltage, a current, a coil resistance, and an inductance of the linear motor. When driving towards the dead center,
At a first time when the predetermined portion passes through the predetermined stroke position, and when the piston portion passes through one dead center and drives toward the other dead center, the predetermined portion again returns to the predetermined position. And a displacement at the first time and the second time are further obtained from the vibration waveform, and a magnitude and the displacement of the predetermined stroke position are obtained;
The drive control device for a linear compressor according to claim 3, wherein the drive control device is calculated from a relationship with a maximum amplitude in the vibration waveform. 5. The drive control device for a linear compressor according to claim 4, wherein the stroke calculation unit calculates the maximum stroke by further obtaining a deviation of the piston unit from a stroke center. 6. The sensor section includes: a magnet section provided at the predetermined portion of the piston section; and a magnetic detection section provided at the predetermined stroke position and detecting a magnetic field of the magnet section. Claims 1-5
The drive control device for a linear compressor according to any one of the above. 7. A drive control method for a linear compressor having a linear motor, wherein a predetermined portion of a piston portion connected to the linear motor is positioned at a predetermined stroke position with respect to a stroke of the piston portion by a sensor portion. Detecting the passage of the vicinity, and approximating the displacement of the piston portion with a sine wave, detecting an excess time in which a predetermined portion of the piston portion exceeds the predetermined stroke position, and detecting the excess time. A drive control method for a linear compressor, comprising: calculating the maximum stroke of the piston portion based on the calculated maximum stroke; and controlling the linear motor in accordance with the calculated maximum stroke. 8. A drive control method for a linear compressor having a linear motor, wherein a predetermined portion of a piston portion connected to the linear motor is moved at a predetermined stroke position with respect to a stroke of the piston portion by a sensor portion. Detecting that the vehicle has passed the vicinity; and obtaining a vibration waveform based on at least an output voltage for driving the linear motor as a waveform corresponding to the displacement of the piston portion, and displacing the vibration waveform corresponding to the predetermined stroke position. A step of calculating a maximum stroke of the piston portion based on a maximum amplitude of the vibration waveform; and a step of controlling the linear motor in accordance with the calculated maximum stroke. Control method. 9. The sensor unit includes: a magnet unit provided at the predetermined portion of the piston unit; and a magnetism detection unit provided at the predetermined stroke position and detecting a magnetic field of the magnet unit. A drive control method for a linear compressor according to claim 7.