KR100575692B1 - Low load driving control apparatus and method for reciprocating compressor - Google Patents

Abstract

The present invention relates to a low load operation control apparatus and method for a reciprocating compressor, and compares a phase difference between a current and a stroke with a low load condition angle to change the stroke so that the phase difference between the current and the stroke is equal to or less than a specific value when a low load is detected. In other words, the operating efficiency of the compressor is improved. To this end, the present invention provides a reciprocating compressor comprising: a current detector for detecting a current applied to the compressor; A voltage detector detecting a voltage applied to the compressor; A stroke estimator for estimating a stroke of the compressor based on the current output from the current detector and the voltage output from the voltage detector; A low load determining unit for calculating a phase difference between the stroke estimate output from the stroke estimating unit and the current of the current detecting unit and determining a low load condition using the phase difference; And a stroke command value generating section for generating a final stroke command value by increasing or decreasing the current stroke command value by the low load determination signal outputted from the low load determination section.

Description

LOW LOAD DRIVING CONTROL APPARATUS AND METHOD FOR RECIPROCATING COMPRESSOR}

1 is a block diagram showing a configuration for a driving control apparatus of a conventional reciprocating compressor.

2 is a flowchart illustrating an operation control method of a conventional reciprocating compressor.

Figure 3 is a block diagram showing a configuration for a low load operation control apparatus of a reciprocating compressor according to an embodiment of the present invention.

FIG. 4 is a graph showing the state in which the stroke is varied so as to follow TCV = 0 at low load in FIG.

5 is an operation flow chart for a low load operation control method of a reciprocating compressor according to an embodiment of the present invention.

***** Description of the symbols for the main parts of the drawings *****

10: current detector 20: voltage detector

30: Stroke estimator 40: Low load discrimination unit

50: Stroke command value decision part 60: Comparator

70: controller

The present invention relates to a low load operation control apparatus and method for a reciprocating compressor. In particular, when the low load is detected by comparing the phase difference between the current and the stroke with the low load condition angle, the stroke is changed so that the phase difference between the current and the stroke is equal to or less than a specific value. A low load operation control apparatus and method for a reciprocating compressor to be controlled.

In general, a reciprocating compressor (Reciprocating Compressor) is a piston in a cylinder reciprocating linearly in the inside of the cylinder to suck and compress the refrigerant gas and discharge, more specifically, according to the method of driving the piston (Recipro) method It can be divided into and linear method.

Recipro method combines the crankshaft with the rotary motor and piston with the crankshaft to convert the rotational force of the rotary motor into linear reciprocating motion, whereas the linear method is applied to the actuator of the linear motor. Directly connecting the piston to reciprocate the piston by the linear motion of the motor.

The present invention relates to a reciprocating compressor applying a linear system.

As described above, the linear reciprocating compressor does not have a crankshaft for converting rotational motion into linear motion and thus has low frictional loss, and thus, the compression efficiency is higher than that of a general compressor.

When the reciprocating compressor is used in a refrigerator or an air conditioner, the compression ratio of the reciprocating compressor may be varied by varying a voltage input to the reciprocating compressor, thereby freezing capacity. Can be controlled.

1 is a block diagram showing a configuration of an operation control apparatus of a conventional reciprocating compressor, and as shown therein, a current detection unit 4 for detecting a motor current applied to a motor; A voltage detector (3) for detecting a motor voltage applied to the motor; A stroke estimator (5) for estimating a stroke based on the detected motor current, motor voltage and motor parameters; A comparator (1) for comparing the stroke estimate value with the stroke command value and outputting a difference signal accordingly; In accordance with the difference signal, the controller 2 is configured to control the stroke by varying the voltage applied to the motor, and the operation of such a conventional apparatus will be described.

First, the current detector 4 detects a motor current applied to the motor, and the voltage detector 3 detects a motor voltage applied to the motor.

At this time, the stroke estimator 5 applies the motor current, the motor voltage, and the motor parameter to the following equation to calculate a stroke estimate, and then applies the stroke estimate to the comparator 1.

[Equation]

Where R: resistance

        L: Inductance

        α: motor constant

Accordingly, the comparator 1 compares the estimated stroke value with the stroke command value and applies a difference signal to the controller 2, whereby the controller 2 varies the voltage applied to the motor and strokes the stroke. To control.

That is, as shown in Fig. 2, the controller 2 decreases the motor applied voltage when the stroke estimate is larger than the stroke command value, and increases the motor applied voltage when the stroke estimate is smaller than the stroke command value.

At this time, the above-described reciprocating compressor performs stroke control by estimating the stroke by using the motor constant α, resistance R and inductance L regardless of the load. When the stroke control is performed, an overstroke occurs, which causes the compressor to be damaged.

The present invention has been made to solve the above problems, and comparing the phase difference between the current and the stroke to the low load condition angle, if the low load is detected by varying the stroke so that the phase difference between the current and stroke is below a specific value, It is an object of the present invention to provide a low load operation control apparatus and method for a reciprocating compressor to improve operation efficiency.

In order to achieve the above object, the present invention provides a reciprocating compressor comprising: a current detector for detecting a current applied to the compressor; A voltage detector detecting a voltage applied to the compressor; A stroke estimator for estimating a stroke of the compressor based on the current output from the current detector and the voltage output from the voltage detector; A low load determining unit for calculating a phase difference between the stroke estimate output from the stroke estimating unit and the current of the current detecting unit, and then determining a low load condition using the phase difference; And a stroke command value generating unit for generating a final stroke command value by increasing or decreasing the current stroke command value by the low load determination signal output from the low load determination unit.

According to an aspect of the present invention, there is provided a method of controlling a reciprocating compressor, the method including: detecting a voltage and a current of a motor currently driven, and estimating a stroke using the motor voltage and the motor current; Comparing the stroke command value with the stroke estimate value and increasing or decreasing the motor applied voltage based on the comparison result; Detecting a phase difference between the estimated stroke and current; The phase difference between the stroke and the current is compared with the low load condition angle, and a process of generating a final stroke command value by increasing or decreasing the current stroke command value based on the comparison result is performed.

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

Figure 3 is a block diagram showing the configuration of an embodiment of the operation control device of the reciprocating compressor of the present invention.

As shown in Fig. 3, the present invention includes a current detecting unit 10 for detecting a current applied to the compressor L.comp; A voltage detector 20 detecting a voltage applied to the compressor L.comp; A stroke estimator 30 estimating a stroke of the compressor L.comp based on the current output from the current detector 10 and the voltage output from the voltage detector 20; and the stroke estimator 30; A low load determining unit 40 for calculating a phase difference between a stroke estimated value output from the current and the current of the current detecting unit 10, and then determining a low load condition using the phase difference; A stroke command value generator 50 is provided to generate the final stroke command value by increasing or decreasing the current stroke command value by the low load determination signal output from the low load determination unit 40.

5 is an operation flowchart of an embodiment of an operation control method of the reciprocating compressor according to the present invention.

As shown in Fig. 5, the present invention includes the steps of detecting the voltage and current of a currently driven motor and estimating a stroke using the motor voltage and the motor current; Comparing the stroke command value with the stroke estimate value and increasing or decreasing the motor applied voltage based on the comparison result; Detecting a phase difference between the estimated stroke and current; The phase difference between the stroke and the current is compared with the low load condition angle, and the current stroke command value is increased or decreased based on the comparison result to generate the final stroke command value. The operation of the present invention will be described.

First, the current detector 10 detects a current applied to the compressor L.comp, and the voltage detector 20 detects a voltage applied to the compressor L.comp.

At this time, the stroke estimator 30 estimates the stroke of the compressor L.comp based on the current output from the current detector 10 and the voltage output from the voltage detector 20, and the comparator 60 The final stroke command value output from the stroke command value generation unit 50 to be described later is compared with the stroke estimate value output from the stroke estimating unit 30, and the difference value thereof is applied to the controller 70. Accordingly, the controller ( 70 controls the stroke by varying the voltage applied to the compressor (L.comp) according to the difference value.

On the other hand, the low load determination unit 40 calculates the phase difference between the stroke estimate output from the stroke estimating unit 30 and the current of the current detector 10, and then determines the low load condition using the phase difference.

That is, the low load discrimination unit 40 compares the phase difference between the stroke and the current with the low load condition angle 120 ° preset by the experiment, and when the phase difference is greater than the low load condition angle 120 °, Discriminate and output a low load discrimination signal accordingly.

The stroke command value generator 50 increases or decreases the current stroke command value by the low load determination signal output from the low load determination unit 40 to generate the final stroke command value.

That is, as shown in FIG. 4, the stroke command value is increased or decreased to operate by finding the point where TCV (Top Clearance) = 0. For example, when the load increases from 1 → 2 → 3 → 4 → 5, the operating point is E → D → C → B → A and if the load decreases from 5 → 4 → 3 → 2 → 1, the operation point moves from A → B → C → D → E.

That is, when the low load determination signal indicates a low load, the stroke command value generating unit 50 sets the low load recognition flag to '1', decreases the current stroke command value by a constant value, and generates the low load stroke command value. If the low load determination signal does not indicate low load and the low load recognition flag is set to '0', the current stroke command value is maintained as it is.

In addition, when the low load determination signal does not indicate low load and the low load recognition flag is set to '1', the stroke command value generation unit 50 compares the current stroke command value with the previous low load stroke command value, Based on the comparison result, the stroke is varied, that is, if the current stroke command value is larger than the previous low load stroke command value, the current stroke command value is kept as it is; Increase.

More specifically, the present invention will be described with reference to Fig. 5, first of all detecting current and voltage applied to the compressor and estimating stroke using the current and voltage.

Then, the stroke command value input by the user is compared with the stroke estimate value, and the voltage applied to the motor is reduced or increased based on the comparison result.

Then, the phase difference between the estimated stroke and the current is detected, and then the phase difference between the stroke and the current is compared with the low load condition angle, and the current stroke command value is increased or decreased based on the comparison result to generate the final stroke command value. do.

That is, the phase difference between the stroke and the current is compared with 120 ° of the low load condition angle preset by the experiment. If it is large, it is determined as a low load. If the phase difference is smaller than the condition angle of 120 °, it is determined as an overload.

If the current load is determined to be low load, the low load recognition flag is set to '1', and then the current stroke command value is decreased by a constant value to generate the low load stroke command value.

On the contrary, if the low load recognition flag is set to '0' and not determined as a low load, the current stroke command value is kept as it is.

If the low load acknowledgment flag is set to '1' and the low load recognition flag is set to '1', the current stroke command value is compared with the previous low load stroke command value, and the stroke is changed based on the comparison result. If is greater than the previous low load stroke command value, the current stroke command value is kept as it is, and if the current stroke command value is smaller than the previous low load stroke command value, the current stroke command value is increased by a constant value.

That is, the present invention compares the phase difference between the current and the stroke with the low load condition angle, and when the low load is detected, the stroke is varied so that the phase difference between the current and the stroke is equal to or less than a specific value.

The specific embodiments or examples made in the detailed description of the present invention are intended to clarify the technical contents of the present invention to the extent that they should not be construed as limited to these specific embodiments and should not be construed in consultation. Various changes can be made within the scope of.

As described in detail above, the present invention compares the phase difference between the current and the stroke with the low load condition angle, and when the low load is detected, the stroke is varied so that the phase difference between the current and the stroke is equal to or less than a specific value, thereby improving the operating efficiency of the compressor. It works.

In addition, the TCV (Top Clearance Volume) can be accurately found at a low load, and there is an effect of preventing the occurrence of overstroke.

Claims (14)

In a reciprocating compressor, A current detector for detecting a current applied to the compressor; A voltage detector detecting a voltage applied to the compressor; A stroke estimator for estimating a stroke of the compressor based on the current output from the current detector and the voltage output from the voltage detector; A low load determining unit for calculating a phase difference between the stroke estimate output from the stroke estimating unit and the current of the current detecting unit and determining a low load condition using the phase difference; And a stroke command value generating unit for generating a final stroke command value by increasing or decreasing the current stroke command value by the low load determination signal output from the low load determination unit. The method of claim 1, wherein the low load determination unit, The phase difference between the stroke and the current is compared with the low load condition angle 120 ° preset by the experiment, and if the phase difference is greater than 120 ° under the low load condition angle, the low load of the reciprocating compressor is characterized in that it is determined. Load operation control device. The stroke command value generating unit according to claim 1, When the low load discrimination signal indicates a low load, the low load operation flag is set to '1', the current stroke command value is decreased by a constant value, and the low load stroke control value of the reciprocating compressor is generated. Device. The stroke command value generating unit according to claim 1, A low load operation control device for a reciprocating compressor, wherein the low load discrimination signal does not indicate low load and maintains the current stroke command value if the low load recognition flag is set to '0'.  The stroke command value generating unit according to claim 1, If the low load determination signal does not indicate low load and the low load acknowledgment flag is set to '1', comparing the current stroke command value with the previous low load stroke command value and varying the stroke based on the comparison result Low load operation control device of a reciprocating compressor characterized in that. The stroke command value generating unit according to claim 5, A low load operation control apparatus for a reciprocating compressor, wherein the current stroke command value is maintained as it is if the current stroke command value is larger than the previous low load stroke command value. The stroke command value generating unit according to claim 5, A low load operation control apparatus for a reciprocating compressor, wherein the current stroke command value is increased by a predetermined value when the current stroke command value is smaller than the previous low load stroke command value. In the operation control method of a reciprocating compressor, Detecting a voltage and a current of a motor currently driven and estimating a stroke using the motor voltage and the motor current; Comparing the stroke command value with the stroke estimate value and increasing or decreasing the motor applied voltage based on the comparison result; Detecting a phase difference between the estimated stroke and current; Low load operation control of the reciprocating compressor, characterized in that the phase difference between the stroke and the current is compared with the low load condition angle, and the final stroke command value is generated by increasing or decreasing the current stroke command value based on the comparison result. Device. The process of claim 8, wherein the generating of the final stroke command value comprises: Comparing the phase difference between the stroke and the current with a low load condition angle 120 ° preset by the experiment; And determining that the phase difference is low when the phase difference is greater than 120 ° of the low load condition angle, and determining the overload when the phase difference is less than 120 ° of the low load condition angle. Way. The process of claim 8, wherein the generating of the final stroke command value comprises: Setting a low load recognition flag to '1' if the low load is determined; And reducing the current stroke command value by a predetermined value to generate the low load stroke command value. The process of claim 8, wherein the generating of the final stroke command value comprises: And if the low load acknowledgment flag is set to '0', the low stroke operation control method of the reciprocating compressor comprising: maintaining the current stroke command value as it is. The process of claim 8, wherein the generating of the final stroke command value comprises: Comparing the current stroke command value with the previous low load stroke command value and varying the stroke based on the comparison result if the low load recognition flag is not set to '1'. Load control method of a reciprocating compressor. The method of claim 12, wherein varying the stroke comprises: And if the current stroke command value is greater than the previous low load stroke command value, maintaining the current stroke command value as it is. The method of claim 12, wherein varying the stroke comprises: And if the current stroke command value is smaller than the previous low load stroke command value, increasing the current stroke command value by a constant value.

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