KR100311418B1 - Apparatus for detecting piston position of linear compressor - Google Patents

Abstract

The present invention relates to a piston position sensing device of a linear compressor, and there is a problem in that it does not accurately detect the stroke in the conventional sensorless method. Therefore, the present invention is provided with a magnetic body inserted into the cylinder and connected to a linear reciprocating piston moving together with the movement of the piston, and an inductive sensor for detecting the position of the piston by the magnitude of the voltage induced by the movement of the magnetic body. To detect the exact position of the piston.

Description

Piston position sensing device of linear compressor {APPARATUS FOR DETECTING PISTON POSITION OF LINEAR COMPRESSOR}

The present invention relates to a piston position sensing device of a linear compressor for accurately detecting the movement of the piston, and in particular, to detect the magnitude of the voltage induced in the induction type sensor installed in the linear compressor to detect the exact position of the piston. It relates to a piston position sensing device of the linear compressor to sense and control the stroke to improve the control performance.

1 is a block diagram of a piston position control apparatus of a linear compressor according to a conventional sensorless method. As shown in FIG. 1, a compressor 11 for varying a stroke by vertical movement of a piston to adjust a cooling force, and a switching signal The switch element 12 for regulating the voltage applied to the compressor 11 by intermitting the AC power input according to the present invention, the current detector 13 for detecting the current applied to the compressor 11, and the compressor ( 11) The stroke is calculated using the voltage detector 14 detecting the voltage between both ends, the current i detected by the current detector 13 and the voltage v detected by the voltage detector 14, and A stroke calculation unit 15 for outputting the calculated stroke measurement value, a rectification unit 16 for smoothing the stroke measurement value calculated by the stroke calculation unit 15 to remove unnecessary portions, and the rectification unit 16 A comparator 17 for comparing an output stroke measurement value with a stroke command value to obtain an error, and a control unit 18 for outputting a stroke for allowing the stroke measurement value to follow the stroke command value using the error provided by the comparator 17. ) And a smoothing unit 19 for smoothing the stroke output from the control unit 18 to the switch element 12.

Looking at the prior art configured in this way in detail as follows.

When 220V AC power is supplied from the power supply voltage terminal, the AC power is supplied to the compressor 11 through the current sensing resistor R and the switch element 12.

Accordingly, a voltage is supplied to the compressor 11.

Then, the piston of the compressor (not shown) reciprocates, and the reciprocating stroke distance of the piston is a stroke, and the stroke is varied to vary the cooling force.

In this case, since the piston is driven by a linear motor, the friction loss can be reduced, resulting in high efficiency.

The piston of the compressor 11 performs the optimum movement according to the pressure of both ends of the piston with respect to the applied voltage.

In order to produce the required cooling force and maintain a high efficiency of compression, the operation must be performed while maintaining a top clearance, which is a distance between the top dead center of the piston and the discharge valve, at a constant distance.

Therefore, when the user sets the temperature of the refrigerator or the air conditioner, a stroke command value proportional to the set temperature information is input to the controller 18 via the comparator 17.

Then, the controller 18 turns on or off the switch element 12 in accordance with the input stroke command value to adjust the voltage supplied to the compressor 11.

Accordingly, the compressor 11 operates, and at this time, the current detector 13 detects an input current i supplied to the compressor 11 through a current sensing resistor R and provides the stroke current to the stroke calculator 15. The voltage detector 14 detects the voltage V across the compressor 11 and provides the voltage V to the stroke calculator 15.

Accordingly, the stroke calculator 15 calculates the stroke using the current i and the voltage V provided by the two detectors 13 and 14 as follows.

Where V _M is the voltage across the compressor, Rac is the body resistance in the compressor, i is the inrush current, and L is the reactance.

When the calculated stroke is output to the rectifier 16, the rectifier 16 rectifies to remove the unnecessary portion and outputs the rectified stroke measurement to the comparator 17.

The comparator 17 then compares the current stroke measurement value with the stroke command value and transmits it to the control unit 18.

Accordingly, when the stroke measurement value is larger than the stroke command value, the control unit 18 outputs a correction stroke for turning off the switch element 12 to the smoothing unit 19 to reduce the voltage supplied to the compressor 11.

The smoothing unit 19 smoothes the stroke and outputs the switch element 12 to the switch element 12 so that the switch element SW is turned off to reduce the voltage supplied to the compressor 11.

When the stroke measurement value is smaller than the stroke command value, the correction stroke for turning on the switch element 12 is output to the smoothing unit 19 in order to increase the voltage supplied to the compressor 11.

The smoothing unit 19 smoothes the correction stroke and outputs it to the switch element 12 to turn it on.

As the switch element 12 is turned on, the voltage supplied to the compressor 11 increases.

Thus, the stroke top dead center is adjusted by decreasing or increasing the voltage supplied to the compressor 11.

In other words, after calculating the stroke with the motor resistance and the motor inductance, the current (i) and voltage (V) detected by the linear compressor (11) are calculated, and the stroke command value can be followed by comparing this value with the stroke command value. Control to maintain the top clearance between the piston top dead center of the compressor and the discharge valve at a constant distance.

However, in the prior art as described above, when detecting and controlling the stroke in a sensorless manner, there is a problem that the stroke is not accurately detected.

Accordingly, an object of the present invention for solving the conventional problems as described above is to provide a piston position detection device of the linear compressor to accurately detect the piston position of the compressor using an inductive sensor.

Another object of the present invention is to provide a piston position sensing device of a linear compressor for detecting the movement of a piston by detecting the magnitude of voltage induced by an inductive sensor.

1 is a block diagram of a piston position control device of a linear compressor according to a conventional sensorless method.

Figure 2 is a block diagram of a piston position detection device of the linear compressor of the present invention.

3 is a detailed structural diagram of an inductive sensor in FIG.

4 is a coil connection diagram in FIG. 3.

5 is a voltage waveform diagram induced by an inductive sensor in FIG.

***** Explanation of symbols for the main parts of the drawing *****

21: piston 22: magnetic material

23: connecting rod 24: inductive sensor

25 fixing part 31 housing

32: core W: winding coil

The present invention for achieving the above object is connected to the piston reciprocating linearly inserted into the cylinder and the magnetic body moving together in accordance with the movement of the piston, and detecting the position of the piston by the magnitude of the voltage induced by the movement of the magnetic body It characterized in that it comprises a voltage organic means.

Hereinafter, with reference to the accompanying drawings in detail as follows.

2 is a structural diagram of a piston position sensing device of the linear compressor according to the present invention. As shown therein, a piston 21 inserted into a cylinder and linearly reciprocating is connected to the piston 21 and reciprocated together with the piston 21. A magnetic body 22, a connecting rod 23 for connecting the piston 21 and the magnetic body 22, and a plurality of curved wires therein, formed in an annular shape is induced by the movement of the magnetic body 22 It consists of an inductive sensor 24 for sensing the magnitude of the voltage.

As shown in FIG. 3, the inductive sensor 24 is formed in an annular shape and fixed by a fixing part, and is located inside the housing 31 and at the side of the magnetic body. The core 32 includes a plurality of winding coils W1, W2, W3, and W4 inserted into the housing 31.

Referring to the operation and effect of the present invention configured as described in detail as follows.

When a voltage is supplied to the compressor, the piston 21 shown in Fig. 2 performs a linear reciprocating motion. The reciprocating stroke distance of the piston is a stroke, and the stroke is varied to adjust the cooling force.

When the piston 21 linearly reciprocates, the magnetic body 22 connected to the piston 21 via the connecting rod 23 also linearly reciprocates.

The magnetic body 22 is formed in an annular shape to move the inside of the inductive sensor 24.

In the inductive sensor 24, the housing 31, which is formed in an annular shape, is fixed to the cover 26 by the fixing part 25 as shown in FIG. 2, and the inside thereof is shown in FIG. The core 32 is fixed to the magnetic body 22 side, and a plurality of winding coils W1, W2, W3, and W4 are inserted into the housing 31.

The wiring of the plurality of winding coils W1, W2, W3, W4 inserted in this way is as shown in FIG.

At this time, when the magnetic body 22 formed in an annular shape moves inside the inductive sensor 24, the voltage as shown in FIG. 5 is induced by the winding coils W1, W2, W3, and W4. Here, when the magnetic body 22 is in the center, it becomes a zero voltage.

The microcomputer (not shown) receives the induced voltage, and detects the peak point of the induced voltage to find the current position of the piston.

Therefore, since the current position of the piston is known accurately, this position is used to control the top clearance between the piston top dead center of the compressor and the discharge valve to be maintained at a constant distance.

As described in detail above, the present invention includes a magnetic body moving together with the piston, and has the effect of detecting the exact position of the piston using an inductive sensor that induces a voltage as the magnetic body moves.

Claims (3)

A magnetic body inserted into the cylinder and connected to a linear reciprocating piston and moving together according to the movement of the piston, and a voltage organic means for detecting the position of the piston by the magnitude of the voltage induced by the movement of the magnetic body. Piston position sensor for linear compressors. According to claim 1, wherein the voltage storage means is formed in an annular shape and the housing which is fixed by the fixing means and the inside of the housing and the core located on the side of the magnetic material and a plurality of inserted into the housing Piston position sensing device of a linear compressor, characterized in that it comprises two winding coils. 3. The piston position sensing apparatus of claim 2, wherein the magnetic body is formed in an annular shape so as to be inserted into the voltage organic means.