KR20030012263A - Stroke comtrol apparatus for reciprocating compressor - Google Patents

Abstract

PURPOSE: An apparatus and method for controlling stroke of reciprocating compressor are provided to compensate error of stroke. CONSTITUTION: An apparatus includes a phase difference detecting part(500) calculating phase difference between current piston stroke and motor current on a certain load and detecting stroke on a point of inflection where TDC(Top Dead Center) is approximately 0; a stroke instruction value memory part(600) receiving the stroke where TDC is approximately 0 from the phase difference detecting part to store as stroke instruction value; and a control part(700) comparing the stroke instruction value stored in the stroke instruction value memory part and current piston stroke to control stroke thereby.

Description

Stroke control device and method of reciprocating compressors {STROKE COMTROL APPARATUS FOR RECIPROCATING COMPRESSOR}

The present invention relates to a reciprocating compressor. In particular, a reciprocating compressor which detects and stores a stroke at the point of 'TDC = 0' under the same load condition before using a product and uses the stroke as a reference stroke in all operating conditions. To a stroke control apparatus and method.

In general, a reciprocating compressor generates a torque by interrupting the power supplied to a coil wound around a multi-phase stator by using a switching element. By sequentially changing the excitation state between the rotor and the stator, The forward rotational torque can be generated by the suction force.

1 is a block diagram showing a configuration of an operation control device of a general reciprocating compressor. As shown in FIG. 1, the piston changes the stroke in vertical motion by the voltage applied to the internal motor according to the stroke command value. A reciprocating compression unit (L.COMP) for adjusting; A voltage detector (30) which detects a voltage generated in the reciprocating compression section (L.COMP) as the stroke is increased by an applied voltage; A current detector 20 which detects a current applied to the reciprocating compressor L.COMP as the stroke is increased by an applied voltage; A microcomputer (40) for calculating a stroke from the voltage and current detected by the voltage detector (30) and the current detector (20), comparing the stroke with a stroke command value, and outputting a switching control signal accordingly; In accordance with the switching control signal of the microcomputer 40, it consists of an electric circuit section 10 for interrupting the AC power to the triac (Tr1) to apply a voltage to the reciprocating compression section (L.COMP), and thus The operation of the conventional apparatus will be described.

First, the reciprocating compression section (L.COMP), the piston is moved up and down by the applied voltage according to the stroke command value set by the user, thereby the stroke is variable to adjust the cooling force.

Meanwhile, the stroke of the triac Tr1 of the electric circuit unit 10 is increased due to a long turn-on period due to the switching control signal of the microcomputer 40, wherein the motor M of the reciprocating compressor L.COMP is increased. The voltage and the current applied to the) are detected by the voltage detector 30 and the current detector 20, and applied to the microcomputer 40.

Then, the microcomputer 40 calculates a stroke using the applied voltage and current detected from the voltage detector 30 and the current detector 20, and compares the stroke with the stroke command value and accordingly switches the control signal. Outputs

That is, when the calculated stroke is smaller than the stroke command value, the microcomputer 40 outputs a switching control signal for lengthening the on-cycle of the triac Tr1, thereby converting the voltage applied to the reciprocating compressor L.COMP. Increase.

Unlike the above, when the calculated stroke is larger than the stroke command value, the microcomputer 40 outputs a switching control signal for shortening the on-cycle of the triac Tr1 and is applied to the reciprocating compression unit L.COMP. Reduce the voltage.

The above-described apparatus calculates the stroke of the point of 'TDC = 0' in a sensorless manner, or detects the stroke of the point of 'TDC = 0' using a sensor and uses it as the stroke command value. The stroke at the point where 'TDC = 0' is changed due to the load change due to the characteristic change or the external environment change, and there is a problem in that the stroke command value must be newly detected at every operation.

The present invention has been made to solve the above problems, before the product launch, after setting the stroke at the point of 'TDC = 0' detected under the same load conditions as the stroke command value, the stroke command value at all operating conditions It is an object of the present invention to provide a stroke control apparatus and method for a reciprocating compressor that compensates for a stroke error by adding or subtracting a correction value previously obtained by an experiment to a stroke command value during load change.

1 is a block diagram showing a configuration of a stroke control device of a general reciprocating compressor.

Figure 2 is a block diagram showing the configuration of the stroke control device of the reciprocating compressor of the present invention.

Figure 3 is an operation flowchart of the stroke control method of the reciprocating compressor of the present invention.

FIG. 4 is a diagram showing a change in phase difference between a stroke and a current with respect to the stroke in FIG.

FIG. 5 is a diagram showing changes in phase difference between voltage and current with respect to stroke in FIG.

** Explanation of symbols for main parts of drawings **

100: electrical circuit unit 200: current detection unit

300: voltage detection unit 400: stroke detection unit

500: Phase difference detection unit 600: Stroke command value

700: control unit 701: comparator

702: stroke control unit

According to the present invention for achieving the above object, in a reciprocating compressor, in a specific load state, after determining the phase difference between the current motor stroke and the motor current, detecting a stroke of 'TDC' 0 'at the inflection point of the phase difference. Detection means; Storage means for receiving a stroke of 'TDC'0' from the detection means and storing it as a stroke command value; And a control means for comparing the stroke command value of the storage means with the current piston stroke and controlling the stroke accordingly.

The present invention for achieving the above object, the first process for detecting a phase difference inflection point by the phase difference between the stroke and the motor current for a specific load; A second step of detecting a stroke value at the phase difference inflection point and storing it as a reference stroke command value; And a third process of comparing the stroke command value with the current stroke value and controlling the stroke accordingly.

Hereinafter, the operation and effects of the stroke control device and method of the reciprocating compressor according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram showing a configuration of a stroke control device of the reciprocating compressor of the present invention, and a current detecting unit 200 for detecting a current applied to a motor; A voltage detector 300 detecting a voltage applied to the motor; A stroke detection unit (400) for detecting strokes using the motor current and the motor voltage; A phase difference detection unit (500) for detecting a phase difference between the stroke and the current and detecting a stroke at an inflection point of the phase difference; A stroke command value storage unit 600 for storing the stroke of the phase difference detection unit 500 as a stroke command value; A controller 700 for comparing the stroke command value with the current piston stroke and outputting a switching control signal for controlling the stroke accordingly; By the switching control signal, the AC power is interrupted by the triac Tr1, and the electric circuit unit 100 applies a voltage to the reciprocating compression unit L.COMP.

The control unit 700 includes a comparator 701 for comparing the stroke command value with the magnitude of the current piston stroke and outputting a comparison signal according thereto; According to the comparison signal of the comparator 701, the stroke control unit 702 for outputting a switching control signal for controlling the voltage applied to the motor.

Fig. 3 is an operation flowchart of the stroke control method of the reciprocating compressor of the present invention, in which a first process SP1 detects a phase difference inflection point by a phase difference between a stroke and a motor current under a specific load condition; Second steps (SP2, SP3) for detecting a stroke value at the phase difference inflection point and storing it as a reference stroke command value; A third process (SP4 to SP7) for comparing the stroke command value with the current stroke value and controlling the stroke accordingly is described. The operation of the present invention will be described.

First, since the general operation is the same as the conventional one, it is omitted.

The present invention detects a voltage and a current applied to a motor under a specific load condition, calculates a stroke, detects an inflection point of the phase difference between the stroke and the current, sets the stroke at the inflection point as the stroke command value, and then The driving of the piston is controlled by the stroke command value, that is, the current detector 200 and the voltage detector 300 detect the current and voltage applied to the motor and apply it to the stroke detector 400.

Accordingly, the stroke detection unit 400 calculates a stroke using the current and the voltage, and applies the stroke to the phase difference detection unit 500. As a result, the phase difference detection unit 500 determines the phase difference between the stroke and the current. Alternatively, after detecting the phase difference between the power supply voltage (220V / 60Hz, 220V / 50Hz, 110V / 60Hz, 110V / 50Hz) and the motor current or the phase difference between the motor current and the voltage, the stroke at the inflection point of the phase difference is used as the stroke command value. Stored in the stroke command value storage unit 600.

At this time, the comparator 701 of the control unit 700 receives the stroke command value from the stroke command value storage unit 600 and compares it with the current motor stroke of the stroke detection unit 400 and compares the comparison signal accordingly with the stroke control unit 702. To apply.

Accordingly, the stroke control unit 702 applies a switching control signal for controlling the stroke to the triac Tr1 of the electric circuit unit 100 according to the comparison signal output from the comparator 701.

Accordingly, the electric circuit unit 100 interrupts the AC power supply to the triac Tr1 by the switching control signal output from the control unit 300, and generates a predetermined voltage for driving the motor M. Applied to M).

As a result, the motor M is driven at a predetermined speed.

If a load variation occurs, the controller 700 sets a new stroke command value by adding or subtracting a corresponding correction value of the lookup table to the stroke command value, and then performs stroke control with the stroke command value.

The look-up table stores in advance the difference between the stroke corresponding to each load and the reference stroke command value as a correction value by experiment.

Referring to FIG. 3, the present invention will be briefly described, in a specific load condition, as shown in FIG. 4, the phase difference inflection point is detected by the phase difference between the stroke and the motor current (SP1, SP2), and then at the phase difference inflection point. Detects the stroke value and stores it as the reference stroke command value (SP3).

The phase difference inflection point can also be detected by the phase difference between the motor applied voltage and the motor current as shown in FIG.

Then, the load fluctuation is determined (SP4), and if no load fluctuation occurs, the stroke command value is compared with the current motor stroke (SP6), thereby controlling the stroke of the motor (SP7).

If a load change occurs, read the correction value from the lockup table, add and subtract the correction value to the stroke command value, correct the stroke command value (SP5), and compare the corrected stroke command value with the current motor stroke (SP6). Then, the stroke of the motor is controlled (SP7).

Here, the phase difference inflection point detecting operation SP1 is repeatedly performed for a predetermined number of times before the product is shipped to detect the stroke.

The look-up table detects the corresponding stroke according to the magnitude of each load by experiment in advance, compares it with the stroke command value, and stores the difference value accordingly as a correction value.

As described in detail above, the present invention sets the stroke at the point of 'TDC = 0' detected under the same load condition before the product is released to the stroke command value, and then uses the load at all operating conditions with the stroke command value. At the time of fluctuation, the stroke command value is compensated by adding or subtracting a correction value previously obtained by experiment.

Claims (15)

In a reciprocating compressor, Detecting means for finding a phase difference between the current piston stroke and the motor current in a specific load state, and detecting a stroke of 'TDC' 0 'at the inflection point of the phase difference; Storage means for receiving a stroke of 'TDC'0' from the detection means and storing it as a stroke command value; And a control means for comparing the stroke command value of the storage means with the current piston stroke and controlling the stroke accordingly. The stroke control apparatus for a reciprocating compressor according to claim 1, wherein the detecting means detects a phase difference between the motor voltage and the motor current, and then detects a stroke of 'TDC' 0 'at an inflection point of the phase difference. The method according to claim 1, wherein the detecting means detects a stroke of 'TDC'0' at the inflection point of the phase difference with respect to the power supply voltage (220V / 60Hz, 220V / 50Hz, 110V / 60Hz, 110V / 50Hz) and the motor current. Stroke control device for reciprocating compressors. The stroke control apparatus for a reciprocating compressor according to claim 1, wherein the detecting means detects a phase difference between the piston speed and the motor current and detects a stroke of 'TDC' 0 'at an inflection point of the phase difference. The stroke control apparatus for a reciprocating compressor according to claim 1, wherein the detecting means detects a phase difference between the piston acceleration and the motor current, and then detects a stroke of 'TDC' 0 'at an inflection point of the phase difference. 2. The stroke control apparatus for a reciprocating compressor according to claim 1, wherein the control means includes correction means for correcting by adding or subtracting a correction value corresponding to a load variation determined by an experiment to the stroke command value. 7. The stroke control apparatus for a reciprocating compressor according to claim 6, wherein the correction means includes a look-up table which stores, by experiment, a correction value calculated according to the load size. A first process of detecting a phase difference inflection point by a phase difference between a stroke and a motor current under a specific load condition; A second step of detecting a stroke value at the phase difference inflection point and storing it as a reference stroke command value; And a third step of comparing the stroke command value with the current stroke value and performing a stroke control accordingly. The stroke control method for a reciprocating compressor according to claim 8, wherein the phase difference inflection point is detected by a phase difference between a motor applied voltage and a motor current. The stroke control method according to claim 8, wherein the phase difference inflection point is detected by the phase difference between the piston speed and the motor current. 12. The stroke control method for a reciprocating compressor according to claim 11, wherein the phase difference inflection point is detected by a phase difference between the piston acceleration and the motor current. 12. The stroke control method of claim 11, wherein the phase difference inflection point is detected by a phase difference with respect to a power supply voltage (220V / 60Hz, 220V / 50Hz, 110V / 60Hz, 110V / 50Hz) and a motor current. . 9. The stroke control method according to claim 8, wherein the phase difference inflection point detection operation is repeated for a predetermined number of times before shipment of the product to detect the stroke. The reciprocating compressor of claim 8, further comprising, by experiment, detecting the corresponding stroke according to the magnitude of each load, comparing the stroke with the stroke command value, and storing the comparison value as a correction value. Stroke control method. The stroke of the reciprocating compressor according to claim 8, wherein the second process includes a step of correcting by adding or subtracting a stroke command value at a particular load by a correction value corresponding to a load change obtained by an experiment when the load fluctuates. Control method.