KR101528473B1 - Apparatus and method for controlling stroke phase of linear compressor - Google Patents

Abstract

The present invention relates to the sensorless control of a linear compressor and, more specifically, to a device and a method to control the stroke phase of a linear compressor capable of improving the transient response of a stroke by adding a phase control part to a closed-loop stroke control device of the linear compressor. According to an embodiment of the present invention, the device to control the stroke phase of a linear compressor, which is a sensorless control device for a linear compressor, comprises a linear compressor modeling part, a piston position estimation part, a piston amplitude estimation part, a current control part, a piston amplitude control part, and a phase control part.

Description

[0001] APPARATUS AND METHOD FOR CONTROLLING STROKE PHASE OF LINEAR COMPRESSOR [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to sensorless control of a linear compressor and more particularly to an apparatus and method for controlling a stroke phase of a linear compressor that further improves stroke transient characteristics by adding a phase control unit to a closed loop control apparatus of a linear compressor. will be.

The present invention is derived from research carried out by the Ministry of Education and the Korea Research Foundation as part of the support of general researchers. [Task Control Number: 9991002083, Title: Study on Dynamic Performance and Operation Efficiency of Linear Compressor].

As the awareness of environmental protection expands, regulations on environmental destruction are accelerated around the world, especially in Europe, and regulations on energy consumption are being strengthened. Accordingly, refrigerators and air conditioners, which are the most energy-consuming household appliances in the home, are becoming major issues.

To meet this trend, manufacturers of air conditioning and refrigeration equipment are making great efforts in R & D to improve the efficiency of compressors. In the case of existing reciprocating compressors, the compressor efficiency (EER: Energy Efficiency Ratio) of 6.0 is the limiting point Is predicted. Therefore, a new mechanism has been actively studied for the purpose of developing a high efficiency compressor with an EER of 6.0 or more.

Among these studies, the linear compressor is an entirely new concept compressor unlike the conventional compressor, and has emerged as an alternative to overcome the existing limitations. The linear compressor is expected to have an electric consumption reduction of about 24% or more as compared with the conventional reciprocating compressor, and the difference between the linear compressor and the conventional reciprocating compressor will be described with reference to FIG.

1 is a view showing a structure of a reciprocating compressor and a linear compressor.

Referring to FIG. 1, FIG. 1 (a) shows the structure of a basic reciprocating compressor, and FIG. 1 (b) shows the structure of a linear compressor.

The conventional reciprocating compressor (Fig. 1 (a)) uses a kinematic element such as a crankshaft to change the motion of the rotating rotary motor to linear motion, while the linear compressor (Fig. 1 (b) , The frictional resistance of the bearing part and the sliding part due to the motion conversion is significantly reduced as compared with the reciprocating compressor and the lateral load generated by the existing crankshaft is eliminated.

That is, the linear compressor is a piston type compressor in which the piston PISTON is directly driven by the linear motor, and all the force driven by the linear compressor is applied in the linear motion direction. Therefore, since the linear compressor does not generate the pushing force in the lateral direction, there is an advantage that the friction loss is reduced as compared with the reciprocating compressor. Because of these advantages, linear motors are being developed as oil-free compressors.

In addition, the linear compressor employs a so-called free piston structure. That is, in the conventional reciprocating compressor, the piston is restrained by the connecting rod and reciprocates within a certain stroke (stroke distance) in the cylinder, while the linear compressor is operated only by the resonance spring The stroke (stroke distance) can be adjusted. Therefore, since the stroke of the linear compressor can be freely adjusted according to the temperature on the system or the ambient temperature, if the linear compressor is applied to the refrigerator, the power consumption can be greatly reduced.

In addition, the linear compressor is remarkably advantageous in noise compared with the conventional reciprocating compressor. That is, since the linear compressor uses not only a low noise level as a whole but also a starting method called "soft start & soft stop" (a phenomenon in which the stroke gradually increases from the stop at the time of the first start) The noise generated by the compressor is relatively small compared to the conventional reciprocating compressor.

Hereinafter, the linear compressor will be described in more detail with reference to the drawings.

2 is a view showing the detailed structure of the linear compressor.

2, the operation principle of the linear compressor will be briefly described. The linear compressor comprises a motor unit, a mechanical unit, a spring unit, a refrigerant suction and discharge unit, an oil supply unit, and a drive control unit. The outer stator 10 includes a coil 11, And a force for vibrating the magnet 12 is generated by the alternating magnetic field caused by the alternating current flowing through the coil 11 and the magnetic field generated by the magnet 12. [ At this time, when the vibrating force for vibrating the magnet 12 is applied to the piston 17 in the cylinder 14 located inside the inner stator 13, the one-degree-of-freedom oscillation vibration consisting of the piston 17 and the resonance spring 18 Resonance of the system occurs. As the vibration amplitude of the piston 17 increases due to the resonance, the vibration of the piston 17 periodically compresses / expands the refrigerant. Further, the refrigerant compressed by the discharge valve 15 and the suction valve 16 is discharged to the outside of the compressor through the discharge pipe.

3 is a diagram showing the principle of operation of the linear motor.

Referring to FIG. 3, when the AC power is applied to the coil 11 of the motor unit, the linear compressor flows alternately in the direction of the current, and flows into the iron core constituting the outer stator 10 and the inner stator 13 flux is alternated according to the direction of the current, so that the N pole S pole is alternately formed on both sides of the stator.

At this time, the magnets 12 fixed to the mover can be formed as S poles and N poles (or both N poles and S poles may be formed) with respect to the outer stator side 10 and the inner stator side 13 .

The mover moves to the left when the current flows in the [A] direction and to the right when the current flows in the [B] direction. 4, when the magnitude of the AC current increases, the magnetic field in the counterclockwise direction increases, and the magnet 12 is pushed to the left. Then, when the alternating current decreases to 0, the magnet 12 is biased to the left as shown in (b) of FIG. When the alternating current flows in the opposite direction after a lapse of time, the direction of the magnetic field is changed in a clockwise direction as shown in Fig. Accordingly, the magnet 12 receives a rightward force, and as a result, the magnet 12 is biased to the right most as shown in (d) of FIG.

If the magnitude of the AC current is 60 Hz and the amplitude of the AC current is 60 Hz and the amplitude of the AC current is 60 Hz while maintaining the frequency of the AC current at a constant value of 60 Hz, the width of the magnet 12, ie, the stroke, . When the stroke of the magnet 12 increases, the linear velocity of the piston 17 connected to the magnet 12 increases to increase the flow rate of refrigerant in the linear compressor. As a result, a larger cooling effect can be obtained.

On the other hand, the conventional reciprocating compressor uses a crankshaft in order to convert the rotational motion of the motor into a linear motion. This makes the reciprocating compressors energy-efficient but maintains safe operation without deviating from the top and bottom of the cylinder because the piston is constrained to the crankshaft. On the other hand, since the linear compressor is not mechanically constrained, it is necessary to precisely control the stroke of the piston in order to securely vibrate the piston in a certain region and not to hit the cylinder head. The exact stroke control of the piston is required. In order to accurately control the stroke of the piston, a technique for precisely grasping the position of the piston is required.

Accordingly, Korean Patent Registration No. 0311417 entitled "Piston position detection circuit of a linear compressor using LVDT" has a reverse polarity protection circuit part for changing the polarity of an input DC voltage and outputting the polarity, An LVDT for detecting a movement of a core connected to the piston when supplying a sine wave generated by the sine wave oscillator and detecting an output voltage corresponding to the sensed movement; And an amplifying and filtering unit for amplifying the output voltage to a predetermined magnitude and filtering and outputting the amplified signal.

The prior art has an advantage that the position of the piston can be detected with a precision of 0.1 mm by detecting the output voltage of the sensor unit installed when the core connected to the piston moves by installing the LVDT in the linear compressor, The position sensors such as the LVDT used are not only low in price but also difficult to be mounted, and there is a problem in that a few strands of wires must come out of the container of the compressor at the time of mounting.

Korean Patent No. 0311417 (Registered on September 25, 2011)

An object of the present invention is to improve the operating efficiency of a linear compressor.

An object of the present invention is to further improve the transient characteristics of a stroke by adding a phase control unit to a closed loop control apparatus for a linear compressor.

The present invention aims at contributing to energy saving and product performance enhancement across the country as a result of widespread application in not only refrigeration appliances such as refrigerators and air conditioners but also industries.

In order to achieve the above object, a stroke phase control apparatus of a linear compressor according to an embodiment of the present invention includes a linear compressor modeling unit, a piston position estimating unit, a piston amplitude estimating unit, a current controlling unit, A piston amplitude control section and a phase control section.

The linear compressor modeling unit models the mechanical equations of the linear compressor and the linear equations of the linear compressor in s-domain. The piston position estimating unit estimates the position of the piston using an input voltage value of the linear compressor measured from a voltage sensor and a current value flowing through the linear compressor measured from the current sensor. The piston amplitude estimator estimates the amplitude of the piston using a phase delay filter. The current control unit and the piston amplitude control unit are included to improve the input / output dynamic characteristics of the stroke. Wherein the phase control unit controls the phase of the stroke based on the phase difference between the phase of the current flowing in the linear compressor estimated based on the phase delay filter and the phase of the stroke estimated based on the phase delay filter, And the phase control unit increases the transient characteristic of the stroke by adding the phase control value of the stroke calculated using the phase difference to the output value of the piston amplitude control unit.

The phase control unit may calculate the phase estimate of the current and the phase estimate of the stroke using the phase delay filter, calculate a phase estimate of the current using the sine function, and a phase of the calculated stroke And calculating the phase control value by multiplying the calculated phase difference by a proportional constant, and the piston position estimating unit may integrate the linear compressor based on the electric equation of the linear compressor, It is possible to estimate the position of the piston.

Meanwhile, the stroke phase control method of a linear compressor according to an embodiment of the present invention includes a linear compressor modeling step, a piston position estimating step, a piston amplitude estimating step, and a phase control step in a sensorless control method of a linear compressor.

The modeling of the linear compressor models the mechanical equations of the linear compressor and the linear equations of the linear compressor in s-domain. The piston position estimating step estimates the position of the piston using the input voltage value of the linear compressor measured from the voltage sensor and the current value flowing through the linear compressor measured from the current sensor. The piston amplitude estimating step estimates the amplitude of the piston using a phase delay filter. Wherein the phase control step includes a step of increasing the input / output dynamic characteristic of the stroke by using a phase difference between a phase of a current flowing in the linear compressor estimated based on the phase delay filter and a phase of the stroke estimated based on the phase delay filter, And the phase control step enhances the transient characteristics of the stroke by adding the phase control value of the stroke calculated using the phase difference to the output value of the piston amplitude control step.

The phase control step may further include calculating a phase estimate of the current and a phase estimate of the stroke using the phase delay filter, and calculating a phase estimate of the current using the sine function and a phase estimate of the calculated current, And calculating the phase control value by multiplying the calculated phase difference by a proportional constant. The piston position estimating step may be performed by an analog method or a digital method by integrating based on the electric equation of the linear compressor, It is possible to estimate the position of the piston.

The present invention has the effect of improving the operating efficiency of the linear compressor.

The present invention has the effect of further improving the transient characteristics of the stroke by adding the phase control unit to the closed loop control apparatus of the linear compressor.

The present invention improves stroke transient characteristics by adding a current control unit to a closed loop control apparatus of a linear compressor, and further improves stroke input / output dynamic characteristics by adding a phase control unit.

The present invention has an effect that the transient characteristics of the stroke can be improved by adding a value proportional to the phase difference between the current phase and the phase on the stroke to the output of the piston amplitude control unit.

Since the stroke of the linear compressor is controlled using the phase control unit, the input / output dynamic characteristics of the stroke are improved and the disturbance is restored much faster than when the stroke is controlled without the phase control.

The present invention can be applied not only to refrigerated appliances such as a refrigerator and an air conditioner but also to a wide range of industries, thereby contributing to energy saving and product performance improvement across the country.

1 is a view showing a structure of a reciprocating compressor and a linear compressor.
2 is a view showing the detailed structure of the linear compressor.
3 is a view showing the operation principle of the linear motor.
4 is a s-domain representation of a closed loop control apparatus for a conventional linear compressor.
5 is a diagram showing an electric circuit equivalent model of a linear motor.
6 is a schematic block diagram of a stroke control apparatus of a conventional linear compressor.
7 is a schematic diagram of a stroke phase control apparatus for a linear compressor according to an embodiment of the present invention.
FIG. 8 is a graph showing a response graph of the amplitude estimate value of the actual stroke and the stroke amplitude command value according to an embodiment of the present invention.
9 is a graph showing a simulation result according to an embodiment of the present invention.
10 is a diagram illustrating a stroke response graph according to an embodiment of the present invention, with or without phase control.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. In the following description of the embodiments of the present invention, specific values are only examples.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to sensorless control of a linear compressor and more particularly to an apparatus and method for controlling a stroke phase of a linear compressor that further improves stroke transient characteristics by adding a phase control unit to a closed loop control apparatus of a linear compressor. will be.

First, a closed loop control device for a linear compressor will be described on the basis of the present invention.

6 is a schematic block diagram of a stroke control apparatus of a conventional linear compressor.

6, a stroke control apparatus of a conventional linear compressor includes a voltage control unit 20 for supplying a voltage for driving a linear compressor COMP, a capacitor 21 connected between the voltage control unit 20 and the linear compressor, A voltage sensor 22 for detecting an input voltage of the linear compressor, a current sensor 23 for detecting a current flowing in the linear compressor, a voltage output from the voltage sensor 22, A microcomputer 24 for receiving a current and calculating a stroke, comparing the calculated stroke with a control target stroke, and then controlling a stroke to be controlled; and a microcomputer 24 for driving the linear compressor according to the stroke determined by the microcomputer 24 And a drive unit 25 for outputting a drive voltage value to the voltage control unit 20. [

4 is a s-domain representation of a closed loop control apparatus for a conventional linear compressor.

Referring to FIG. 4, a conventional closed loop control apparatus for a linear compressor includes a linear compressor modeling unit 30, a piston position estimating unit 31, a piston amplitude estimating unit 32, a current controlling unit 33, And a control unit 34.

The linear compressor modeling unit 30 models the mechanical equations of the linear compressor expressed by Equation (1) and the electric equations of the linear compressor expressed by Equation (2) as s-domains.

More specifically, the mechanical equation of a linear motor in a linear compressor can be expressed as Equation 1.

[Formula 1]

In this case, M is the equivalent mass of the piston and the moving coil, C is the viscous damping coefficient, K is the spring constant, α is the thrust constant of the linear motor, A _p is the cross sectional area of the piston, x (t) (t) denotes a current flowing in the windings of the linear compressor, and? P (t) denotes a pressure difference between the chamber of the linear compressor and the rear surface of the piston.

On the other hand, the electric equation of the linear compressor can be derived from Fig.

5 is a diagram showing an electric circuit equivalent model of a linear motor.

Referring to FIG. 5, the electric equation of a linear motor in a linear compressor can be expressed by a linear differential equation, The thrust Fe of the linear motor can be expressed in a linear form as shown in Equation 3.

[Formula 2]

[Formula 3]

는 마그네트(12)의 운동에 의하여 권선코일(11)에 발생하는 역기전력을 의미한다.In Equation 2, L _e denotes the effective inductance of the coil 11, R _e denotes the effective resistance, v (t) denotes the power supply voltage (or input voltage) of the linear compressor,

Means a back electromotive force generated in the winding coil 11 by the motion of the magnet 12.

Therefore, modeling the mechanical equation of the linear compressor expressed by Equation (1) and the electrical equation of the linear compressor expressed by Equation (2) as s-domain can be expressed as (30) .

The piston position estimating unit 31 estimates the position of the piston using the input voltage value of the linear compressor measured from the voltage sensor 22 and the current value flowing through the winding of the linear compressor measured from the current sensor 23. At this time, the position of the piston can be estimated by implementing the analog method of Equation 5 or the digital method of Equation 6.

More specifically, since the linear compressor is not mechanically constrained, it is necessary to precisely control the stroke of the piston in order to securely vibrate the piston in a certain region and not hit the cylinder head. In addition, precise stroke control of the piston is also required to control the flow rate of the refrigerant for cooling. Therefore, accurate positional information of the piston is required for this purpose. Hereinafter, one method of indirectly estimating the position of the piston is shown.

Equation 2 representing the electric equation of the linear motor can be expressed as Equation 4 with respect to x (t).

[Formula 4]

는 식 4를 적분함으로써 구할 수 있으며, 이는 식 5와 같이 나타낼 수 있다. And the position estimate of the piston

Can be obtained by integrating Equation (4), which can be expressed as Equation (5).

[Formula 5]

Therefore, using Equation 5, the position of the piston can be indirectly estimated. Equation (5) can be used to estimate the position of the piston in an analog manner, while Equation (6) can be used to estimate the position of the piston in a digital manner.

[Formula 6]

Here, T denotes a sampling period.

On the other hand, in the conventional reciprocating compressor, the piston is restrained by the crankshaft (CRANKSHAFT) and reciprocates in a certain stroke (stroke distance) in the cylinder, while the piston 17 in the linear compressor is not restricted The stroke can be adjusted because it is supported by the resonance spring 18. Therefore, since the linear compressor is free from stroke control according to the temperature of the system or the ambient temperature, it has a great effect on reducing power consumption when applied to a refrigerator. At this time, in order to control the cooling capacity of the refrigerator or the air conditioner to which the linear compressor is applied, it is necessary to control the distance that the piston 17 moves for a unit time, that is, the speed of the piston 17. This adjusts the frequency or stroke of the linear motor It is possible. In most cases it is common to set the frequency fixed (for example 60 Hz) and to change the stroke.

If the piston position of the linear motor is expressed as Equation 7, the stroke becomes 2 x m. That is, controlling the stroke of the piston is the same as controlling the magnitude of X _m (amplitude), which implies that X _m should be estimated from the position waveform of the piston expressed in Eq.

[Equation 7]

Hereinafter, a method of using a phase delay filter as a method of estimating the amplitude of a piston will be described.

The piston amplitude estimating section 32 estimates the amplitude of the piston using a phase delay filter, where the phase delay filter can be expressed as Eq.

[Equation 8]

=1이면, 식 9 및 식 10이 성립한다.At this time,

= 1, Equation 9 and Equation 10 are established.

[Equation 9]

[Equation 10]

=1이면, 식 8은 90°(

라디안) 위상지연 필터 기능을 한다.In other words,

= 1, Equation 8 is 90 DEG (

Radian) phase delay filter.

Then, let x _d (t) denote that x (t) in Eq. (7) passes through the 90 ° phase delay filter, x _d (t) can be expressed as Eq.

[Equation 11]

Therefore, Equation 12 can be derived using Equation 7 and Equation 11, and Equation 12 can be used to estimate the amplitude of the piston.

[Equation 12]

In FIG. 4, the current control unit 33 and the piston amplitude control unit 34 are provided for improving the input / output dynamic characteristics of the stroke, and D (s) is an external force applied to analyze the dynamic performance of the closed loop control device of the linear compressor. The term means disturbance input.

It is another object of the present invention to further improve the transient characteristics of the stroke by adding a phase control unit to the closed loop control apparatus of the conventional linear compressor as described above. That is, in order to increase the acceleration of the stroke input and the disturbance input to the closed loop control apparatus of the conventional linear compressor described with reference to FIG. 4, that is, to improve the input / output dynamic characteristics of the stroke, The phase control unit 40 is further inserted.

7 is a schematic diagram of a stroke phase control apparatus for a linear compressor according to an embodiment of the present invention.

7, the stroke phase control apparatus 700 of the linear compressor of the present invention further includes a phase control unit 40 for further improving the input / output dynamic characteristics of the stroke in the closed loop control apparatus of the conventional linear compressor Lt; / RTI >

The phase control unit 40 uses a phase difference between a phase of a current flowing in a linear compressor estimated on the basis of a phase delay filter and a phase of a stroke estimated based on a phase delay filter so as to improve the input / And the phase control value of the stroke calculated using the phase difference is added to the output value of the piston amplitude control unit 34 to improve the transient characteristics of the stroke.

More specifically, in the present invention, a current phase estimator for estimating the phase of the current and a stroke phase estimator for estimating the phase of the stroke may be implemented in order to improve the transient characteristics of the stroke, , And the stroke phase estimator can be expressed as Equation (14). Equation (13) and Equation (14) can be derived using Equation (8) expressing a phase delay filter.

[Formula 13]

[Equation 14]

는 리니어 압축기의 권선에 흐르는 전류의 위상 추정치를 나타내고, i_d는 위상지연필터(식 8)를 이용하여 위상이 90°지연된 전류값을 나타내며, i는 측정된 전류값을 나타낸다.At this time,

I _d represents a current value delayed by 90 ° using a phase delay filter (Eq. 8), and i represents a measured current value.

는 스트로크의 위상 추정치를 나타내고,

는 위상지연필터(식 8)를 이용하여 위상이 90°지연된 추정된 스트로크 값을 나타내며,

는 추정된 스트로크 값을 나타낸다.Also,

Represents the phase estimate of the stroke,

Represents an estimated stroke value whose phase is delayed by 90 [deg.] Using the phase delay filter (Eq. 8)

Represents an estimated stroke value.

At this time, the phase difference between the phase of the current and the phase of the stroke changes within 180 degrees, and thus exists at the second upper limit. Therefore, the phase difference obtained by subtracting the phase estimate of the stroke from the phase estimate of the current using the sine function has a minus (-) value, which can be displayed by converting the phase difference to a positive (+) value as shown in equation (15).

[Formula 15]

At this time, Ø represents the phase difference between the phase estimate of the current and the phase estimate of the stroke.

The phase control unit 40 can be implemented by multiplying the converted value of the phase difference (that is, the phase difference -sin (?) Converted into the positive value) obtained in Equation 15 by the proportional coefficient k _ph . Therefore, the output value of the phase control unit 40 is a value obtained by multiplying the converted value of the phase difference by the proportional coefficient, which can be regarded as a phase control value of the stroke for improving the input / output dynamic characteristics of the stroke.

By adding the phase control value of the stroke calculated through the phase control section 40 to the output value of the piston amplitude control section 34, the transient characteristics of the stroke are further improved as compared with the closed loop control device of the conventional linear compressor, Also, there is a property that can be returned much faster for disturbance input.

Hereinafter, the results of the simulation performed to verify the effects of the present invention will be described.

=0.01[m]을 스텝 입력하고, t=0.5[sec]에서 외란 입력 D(s)=25[V]를 스텝 입력하고, t=1[sec]에서

=0.01[m]에서

=0.03[m]로 변경하고, t=1.5[sec]에서 외란 입력 D(s)=-25[V]를 스텝 입력하였고, 마지막으로 t=2[sec]에서

=0.03[m]에서

=0.02[m]로 변경하였을 때의 모의실험을 수행하였다. 이에 대한 결과 그래프는 도 8 및 도 9와 같다.7, the proportional coefficient used in the stroke phase control apparatus is _kps = 52, and the integral coefficient is _ks = 57.3. The proportional coefficient used in the current controller is k _pI = 13.1 and the integral coefficient is k _II = 18.5. And a median of M = 0.186 kg, C = 5 Ns / m, K = 62,500 N / m, a = 60 Vs / m, L _e = 0.11 H, and R _e = For a linear compressor with a variable, at t = 0

= 0.01 [m] is inputted step by step, and disturbance input D (s) = 25 [V] is inputted step by step at t = 1 [sec]

= 0.01 [m]

= 0.03 [m], and the disturbance input D (s) = - 25 [V] was input stepwise at t = 1.5 [sec]. Finally, at t = 2 [sec]

= 0.03 [m]

= 0.02 [m]. The resultant graph is shown in Figs. 8 and 9.

FIG. 8 is a graph showing a response graph of the amplitude estimate value of the actual stroke and the stroke amplitude command value according to an embodiment of the present invention.

Referring to the graph of FIG. 8, it can be seen that the stroke reaches a steady state at about 0.03 seconds. Then, when the disturbance is applied in 0.5 second, the steady state is reached after about 0.07 second, and it can be confirmed that the command value is well followed. Also, even if the command value is changed from 0.01 [m] to 0.03 [m] in one second, it can be confirmed that the command value is accurately followed.

9 is a graph showing a simulation result according to an embodiment of the present invention.

Referring to Fig. 9, Fig. 9 (a) shows the phase of the current near the initial start time, and Fig. 9 (b) shows the phase of the stroke near the initial start time. Figure 9 (c) shows the waveform of the current. 9 (d) shows the output waveform of the piston position estimating unit 31, and it can be confirmed that there is hardly any error in the steady state.

10 is a diagram illustrating a stroke response graph according to an embodiment of the present invention, with or without phase control.

10 shows the case where the phase control unit 40 is not provided (FIG. 10 (a)) and the phase control unit 40 in the state where the current control unit 33 is removed in FIG. 7 in order to more clearly see the performance of the phase control unit 40. [ (Fig. 10 (b)). That is, it can be confirmed that the case of controlling the stroke by phase control (Fig. 10 (b)) returns much faster than the case of controlling the stroke without phase control (Fig. 10 (a)).

Therefore, the present invention is simulated in order to demonstrate the feasibility of the stroke phase control apparatus 700 of the linear compressor. As a result, it has been found that the case where the stroke is controlled through the phase control unit 40 is controlled without the phase control unit 40 The initial response characteristics were improved, and the improvement of the performance in which the error of the steady state was decreased was confirmed. That is, the present invention improves the stroke transient characteristics by adding the current control unit 33 to the closed loop control apparatus of the linear compressor, and further improves the input / output dynamic characteristics of the stroke by adding the phase control unit 40 .

Accordingly, it has been confirmed that the technology of the present invention is applicable to a linear compressor applied to an actual refrigerator or an air conditioner, and as the technology of the present invention is applied not only to refrigerated appliances such as a refrigerator and an air conditioner but also to all industries, It is possible to contribute to a reduction in cost and an improvement in product performance.

11 is a flowchart of a stroke phase control method of a linear compressor according to an embodiment of the present invention.

Hereinafter, the flowchart will be briefly described based on the details described above.

11, in the stroke phase control method of the linear compressor of the present invention, the linear compressor modeling unit 30 models the mechanical equations of the linear compressor and the linear equations of the linear compressor as s-domains (S1100). This can be modeled through Equations 1 to 3, and a detailed description thereof will be made with reference to the above description.

Next, the piston position estimating unit 31 estimates the position of the piston using the input voltage value measured from the voltage sensor and the current value measured from the current sensor (S1200). In this case, the position of the piston can be estimated by implementing the analog method of Equation 5 or the digital method of Equation 6, and a detailed description thereof will be referred to the above description.

Next, the piston amplitude estimating unit 32 estimates the amplitude of the piston using the phase delay filter of Equation 8 (S1300). At this time, the piston amplitude estimating unit 32 can estimate the amplitude of the piston through Equations 7 to 12, and a detailed description thereof will be made with reference to the above description.

Next, the phase control unit 40 uses the phase difference between the phase of the estimated current based on the phase delay filter and the phase of the estimated stroke based on the phase delay filter to calculate the phase control value of the stroke, which improves the input / output dynamic characteristics of the stroke (S1400). At this time, the phase control unit 40 can calculate the phase control value of the stroke through Equations 13 to 15. Here, the phase control value of the stroke is a value obtained by multiplying the converted value of the phase difference by the proportional coefficient value, For a detailed description, reference is made to the above description.

Next, the phase control unit 40 can improve the transient characteristics of the stroke by adding the phase control value of the stroke calculated in step S1400 to the output value of the piston amplitude control unit (S1500).

Therefore, the present invention is characterized in that the transient characteristics of the stroke are further improved as compared with the closed loop control apparatus of the conventional linear compressor, and furthermore, the disturbance input can be recovered much more quickly.

The stroke phase control method of a linear compressor according to an embodiment of the present invention may be implemented in the form of a program command that can be executed through various computer means and recorded in a computer readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the medium may be those specially designed and constructed for the present invention or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

As described above, the present invention has been described with reference to particular embodiments, such as specific elements, and specific embodiments and drawings. However, it should be understood that the present invention is not limited to the above- And various modifications and changes may be made thereto by those skilled in the art to which the present invention pertains.

Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments described, and all of the equivalents or equivalents of the claims, as well as the following claims, belong to the scope of the present invention .

700: Stroke phase control device of linear compressor
30: Linear compressor modeling unit 31: Piston position estimating unit
32: Piston amplitude estimation unit 33: Current control unit
34: Piston amplitude control unit 40: Phase control unit

Claims (6)

A sensorless control apparatus for a linear compressor,
A linear compressor modeling unit for modeling the mechanical equation of the linear compressor and the electric equation of the linear compressor in s-domain;
A piston position estimating unit for estimating a position of a piston using an input voltage value of the linear compressor measured from a voltage sensor and a current value flowing through the linear compressor measured by the current sensor;
A piston amplitude estimator for estimating the amplitude of the piston using a phase delay filter;
A current controller for improving the input / output dynamic characteristics of the stroke;
A piston amplitude controller for improving the input / output dynamic characteristics of the stroke; And
A phase control value of the stroke that improves the input / output dynamic characteristics of the stroke by using a phase difference between a phase of a current flowing in the linear compressor estimated based on the phase delay filter and a phase of the stroke estimated based on the phase delay filter, A phase control unit for calculating a phase shift amount;
Lt; / RTI >
The phase control unit
And adding the phase control value of the stroke calculated using the phase difference to the output value of the piston amplitude control unit to improve the transient characteristic of the stroke
And the stroke phase control device of the linear compressor. The method according to claim 1,
The phase control unit
Calculating a phase estimate of the current using the phase delay filter and a phase estimate of the stroke, calculating a phase difference between the calculated phase estimate of the current and the phase estimate of the calculated phase using the sine function , And calculating the phase control value by multiplying the calculated phase difference by a proportional constant
And the stroke phase control device of the linear compressor. The method according to claim 1,
The piston position estimating unit
Estimating the position of the piston in an analog or digital manner by integrating based on the electrical equations of the linear compressor
And the stroke phase control device of the linear compressor. In a sensorless control method for a linear compressor,
A linear compressor modeling step of modeling the mechanical equation of the linear compressor and the electric equation of the linear compressor into an s-domain;
A piston position estimating step of estimating a position of the piston by using an input voltage value of the linear compressor measured from the voltage sensor and a current value flowing through the linear compressor measured from the current sensor;
A piston amplitude estimating step of estimating an amplitude of the piston using a phase delay filter; And
A phase control value of the stroke for improving the input / output dynamic characteristics of the stroke by using a phase difference between a phase of a current flowing in the linear compressor estimated based on the phase delay filter and a phase of a stroke estimated based on the phase delay filter, A phase control step of computing;
Lt; / RTI >
The phase control step
And increasing the transient characteristic of the stroke by adding the phase control value of the stroke calculated using the phase difference to the output value of the piston amplitude control step
And the stroke phase of the linear compressor. 5. The method of claim 4,
The phase control step
Calculating a phase estimate of the current using the phase delay filter and a phase estimate of the stroke, calculating a phase difference between the calculated phase estimate of the current and the phase estimate of the calculated phase using the sine function , And calculating the phase control value by multiplying the calculated phase difference by a proportional constant
And the stroke phase of the linear compressor. 5. The method of claim 4,
The piston position estimating step
Estimating the position of the piston in an analog or digital manner by integrating based on the electrical equations of the linear compressor
And the stroke phase of the linear compressor.

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