KR100641114B1 - Driving control apparatus and method for reciprocating compressor - Google Patents

Abstract

The present invention relates to an operation control apparatus and method for a reciprocating compressor. During operation of the reciprocating compressor, the load is changed by following the mechanical resonance frequency using the current integral value and the stroke for one cycle whenever the load is changed. Even when the compressor is to improve the operating efficiency. To this end, the present invention comprises a stroke estimating unit for estimating the stroke of the compressor by the current and voltage applied to the reciprocating compressor; And a driving frequency command value determining unit for obtaining a resonance point using an integrated value of the stroke estimate output from the stroke estimating unit and the current applied to the reciprocating compressor, and determining an operating frequency of the resonance point as an operating frequency command value. .

Description

Operation Control System and Method of Reciprocating Compressor {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 the configuration of the operation control apparatus of the reciprocating compressor according to an embodiment of the present invention.

FIG. 4 is a graph showing the resonance frequency in FIG. 3 when the sum of the product of the current integral and the stroke for one period is the maximum; FIG.

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

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

10: current detector 20: voltage detector

30: Stroke estimating unit 40: Operation frequency command value determining unit

50: comparator 60: controller

The present invention relates to an operation control apparatus and method for a reciprocating compressor. In particular, during the operation of a reciprocating compressor, a reciprocating type that follows a mechanical resonance frequency by using a current integral and a stroke for one cycle whenever the load is varied. It relates to an operation control apparatus and a method of a compressor.

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 stroke estimate with the stroke command value and applies a difference signal to the controller 2 according to which the controller 2 varies the voltage applied to the motor to make a 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.

Here, the above-described conventional reciprocating compressor estimates a stroke without varying the operating frequency, compares the stroke estimated value with the stroke command value, and drives the variable voltage applied to the motor based on the comparison result. Even if the mechanical resonance frequency is changed due to fluctuation, there is a problem in that the driving efficiency is lowered by always driving the reciprocating compressor at the same operating frequency.

The present invention has been made to solve the above problems, and during operation of the reciprocating compressor, when the load is changed, by following the mechanical resonance frequency by using the current integral value and stroke for one cycle, when the load changes It is an object of the present invention to provide an operation control apparatus and method for a reciprocating compressor to improve the operation efficiency of the compressor.

The present invention for achieving the above object,
A stroke estimating unit estimating a stroke of the compressor based on a current and a voltage applied to the reciprocating compressor;
And a driving frequency command value determining unit which obtains a resonance point by using the integral of the stroke estimate output from the stroke estimating unit and the current applied to the reciprocating compressor, and determines the operating frequency of the resonance point as the operating frequency command value. It features.

The present invention for achieving the above object,
Integrating a current applied to the reciprocating compressor, and then calculating a sum of a product of a current integral and a stroke for a current period;
A resonance point is obtained by a sum of a product of current integration and a stroke multiplied during the current period, and a process of determining a frequency at the resonance point as an operating frequency command value 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.

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First, in the present invention, as shown in FIG. 4, when a phase difference between a stroke and a current occurs at 90 ° under a constant load condition, resonance occurs, and the sum of the product of the integrated value of the current and the stroke for one period becomes the maximum. Note that we have noticed that resonance occurs at this point.

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) for estimating 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); An operating frequency command value determining unit for obtaining a resonance point by using the stroke estimate output from the stroke estimating unit 30 and a value obtained by integrating the current of the current detector 10, and determining an operating frequency of the resonance point as an operating frequency command value ( 40); A comparator (50) for comparing the stroke estimated value output from the stroke estimating unit (30) with the stroke command value and outputting a difference value according thereto; The controller 60 controls the stroke by varying the driving frequency according to the driving frequency command value and varying the voltage applied to the compressor L.comp according to the difference value output from the comparator 50.

7 is an operation flowchart of an embodiment of the operation control method of the reciprocating compressor of the present invention.

As shown in Fig. 7, the present invention includes the steps of detecting current and voltage applied to the compressor and estimating the stroke using the current and voltage; Integrating the current during the one period, and then calculating a sum of the product of the current and the stroke during the one period; The resonance point is obtained by the sum of the product of the current integral and the stroke multiplied during the current period, and the frequency at the resonance point is determined as the operation frequency 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.

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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 50 calculates the stroke of the compressor L.comp. The stroke command value is compared with the stroke estimate output from the stroke estimating unit 30, and a difference value corresponding thereto is applied to the controller 60. Accordingly, the controller 80 supplies the compressor L.comp according to the difference value. The stroke is controlled by varying the applied voltage.
On the other hand, the driving frequency command value determination unit 40 obtains a resonance point using the integral value of the stroke output from the stroke estimating unit 30 and the current output from the current detection unit 10, and calculates the operating frequency of the resonance point. Determined by the operation frequency command value.

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The operation frequency command value determining unit 40 determines the operating frequency at that time as the operation frequency command value when the sum of the current integral value and the stroke for one period is maximum. Compared to the sum of the product of the current integral and the stroke for the previous period, the operating frequency command value is determined by increasing or decreasing the frequency based on the comparison result.

That is, the operating frequency command value determining unit 40, if the sum of the product of the stroke and the current integral value during the current period is greater than the sum of the product of the stroke and the current integral value during the previous period, the state of the current operating frequency is The operating frequency command value is determined by increasing or decreasing the operating frequency by determining whether it is increasing.If the operating frequency is currently increasing, the operating frequency is continuously increased, and the sum of the product of the current integral and the stroke for one period is multiplied. When it reaches the maximum, the operating frequency at that time is determined as the operating frequency command value. On the contrary, if the current operating frequency is not increasing, the operating frequency is continuously decreased, and the sum of the current integral and the stroke multiplied for one period is the maximum. If is, the operation frequency at that time is determined as the operation frequency command value.

The operation frequency command value determination unit 40 determines that the sum of the product of the current integral and the stroke during the current period is less than the sum of the product of the current integral and the stroke during the previous period, If it is determined that the state is decreasing, and it is determined that the current operating frequency is decreasing, the operating frequency is continuously increased.If the sum of the current integral and the stroke multiplied for one period becomes the maximum, the operating frequency at that time is determined. If the current frequency is not decreasing and the current frequency is not decreasing, the operation frequency is continuously decreased. If the sum of the product of the current integral and the stroke for one period becomes the maximum, the operating frequency at that time is the operating frequency. Determined by the setpoint.

Thereafter, the controller 60 controls the driving of the motor by varying the current driving frequency by the driving frequency command value output from the driving frequency command value determination unit 40.

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 current is integrated and then the sum of the product of the current integral and the stroke for the current period is calculated.

Then, the resonance point is obtained by the sum of the current integrated value and the stroke multiplied during the current period, and the frequency at the resonance point is determined as the operating frequency command value.

Here, the operation frequency determination value determination process will be described in detail.

First, if the sum of the product of the current integral and the stroke for one cycle is the maximum, the operating frequency at that time is determined as the operating frequency command value.

That is, the sum of the product of the current integral and the stroke for one period is compared with the sum of the product of the stroke and the current integral for the previous period, and the result of the comparison is the product of the current integral and the stroke for the current period. If the sum of the values is greater than the sum of the current integral and the stroke multiplied during the previous period, and if the current operating frequency is increasing, the operating frequency is continuously increased, and the current integral and the stroke for one period are When the sum of the multiplied values is maximum, the operating frequency at that time is determined as the operating frequency command value.

If the sum of the product of the current integral and the stroke for the current period is greater than the sum of the product of the current integral and the stroke for the previous period, and the current operating frequency is not increasing, If it continues to decrease and the value obtained by multiplying the current integral and the stroke for one cycle becomes the maximum, the operating frequency at that time is determined as the operating frequency setpoint.

As a result of the comparison, if the sum of the product of the current integral and the stroke during the current period is less than the sum of the product of the current integral and the stroke during the previous period and the operation frequency is continuously increased, the operation frequency is continuously increased. If the sum of the product of the current integral and the stroke for one cycle becomes the maximum, the operating frequency at that time is determined as the operating frequency command value.

If the sum of the product of the current integral and the stroke for the current period is less than the sum of the product of the current integral and the stroke for the previous period and the current operating frequency is not decreasing, the current operating frequency is continued. When it decreases and the sum of the multiplication of the current integral and the stroke for one cycle becomes the maximum, the operating frequency at that time is determined as the operating frequency command value.

In other words, according to the present invention, during operation of a reciprocating compressor, a mechanical resonance frequency is searched and operated by using a current integral value and a stroke for one cycle whenever the load is varied.

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 is to operate the compressor even when the load is changed by following the mechanical resonance frequency by using the current integral value and the stroke for one cycle during the operation of the reciprocating compressor. Has the effect of improving.

Claims (18)

A stroke estimating unit estimating a stroke of the compressor based on a current and a voltage applied to the reciprocating compressor; And an operating frequency command value determining unit for obtaining a resonance point using an integral value of the stroke estimate output from the stroke estimating unit and a current applied to the reciprocating compressor, and determining an operating frequency of the resonance point as an operating frequency command value. Operation control apparatus of the reciprocating compressor. The method of claim 1, wherein the operation frequency command value determination unit, An operation control apparatus for a reciprocating compressor, characterized in that the operation frequency at that time is determined as the operation frequency command value when the sum of the product of the stroke and the current integral value for one cycle becomes maximum. The method of claim 1, wherein the operation frequency command value determination unit, Comparing the product of the integral of the current and stroke for one cycle with the sum of the product of the stroke and current integral for the previous cycle, and determining the operating frequency setpoint by increasing or decreasing the frequency based on the comparison result. Operation control apparatus of the reciprocating compressor characterized in that. The method of claim 3, wherein the operation frequency command value determination unit, If the sum of the product of the current integral and the stroke for the current period is greater than the sum of the product of the current integral and the stroke for the previous period, it is determined whether the state of the current operating frequency is increasing and based on the result of the judgment. Operating control device for a reciprocating compressor, characterized in that for determining the operating frequency command value by increasing or decreasing the operating frequency. The method of claim 4, wherein the operation frequency command value determination unit, If the current operating frequency is increasing, the operating frequency continues to increase, and if the sum of the product of the current integral and the stroke for one period becomes the maximum, the operating frequency at that time is determined as the operating frequency command value. Operation control device of same type compressor. The method of claim 4, wherein the operation frequency command value determination unit, If the current operating frequency is not increasing, the operating frequency is continuously decreased. If the sum of the product of the current integral and the stroke for one period is '0', the operating frequency at that time is determined as the operating frequency command value. Operation control apparatus of the reciprocating compressor. The method of claim 3, wherein the operation frequency command value determination unit, If the sum of the product of the current integral and the stroke for one period is less than the sum of the product of the current integration and the stroke for the previous period, it is determined whether the state of the current operating frequency is decreasing, and the result of the judgment An operating control device for a reciprocating compressor, characterized in that for determining the operating frequency command value by increasing or decreasing the operating frequency. The method of claim 7, wherein the operation frequency command value determination unit, If the current operating frequency is decreasing, the operating frequency continues to increase, and if the sum of the product of the current integral and the stroke for one period becomes the maximum, the operating frequency at that time is determined as the operating frequency command value. Operation control device of same type compressor. The method of claim 8, wherein the operation frequency command value determination unit, If the current operating frequency is not decreasing, the operating frequency is continuously decreased, and when the sum of the product of the current integral and the stroke for one period becomes the maximum, the operating frequency at that time is determined as the operating frequency command value. Operation control device of the reciprocating compressor. Integrating a current applied to the reciprocating compressor, and then calculating a sum of a product of a current integral and a stroke for a current period; And calculating a resonance point by the sum of the current integral value and the stroke product of the current period, and determining a frequency at the resonance point as an operation frequency command value. The method of claim 10, wherein the determining of the driving frequency command value comprises: And when the sum of the product of the current integral and the stroke multiplied for one period is maximum, determining the operation frequency at that time as the operation frequency command value. The method of claim 10, wherein the determining of the driving frequency command value comprises: Compare the sum of the product of the current integral and the stroke for one period with the sum of the product of the current integral and the stroke for the previous period, And operating frequency command value by increasing or decreasing the frequency based on the comparison result. The method of claim 12, wherein the step of determining the operating frequency command value by increasing or decreasing the frequency, If the sum of current multiplication times and strokes for the current period is greater than the sum of current multiplication times and strokes for the previous period, And determining whether a current operating frequency is increasing, and determining an operating frequency command value by increasing or decreasing the operating frequency based on the determination result. The method of claim 13, If the current operating frequency is increasing, continue to increase the operating frequency, And when the sum of the product of the current integral and the stroke multiplied for one period is maximum, determining the operation frequency at that time as the operation frequency command value. The method of claim 13, If the current operating frequency is not increasing, the operation frequency is continuously reduced, and if the sum of the product of the current integral value and the stroke for one period becomes the maximum, determining the operation frequency at that time as the operation frequency command value. Operation control method of the reciprocating compressor, characterized in that. The method of claim 12, wherein the determining of the operating frequency command value by increasing or decreasing the frequency comprises: If the sum of the current integral and the stroke multiplied by the current period is less than the sum of the current integral and the stroke multiplied by the previous period, And determining whether the state of the current operating frequency is decreasing, and determining the operating frequency command value by increasing or decreasing the operating frequency based on the determination result. The method of claim 16, If the current operating frequency is decreasing, continue to increase the operating frequency, And when the sum of the product of the current integral and the stroke multiplied for one period is maximum, determining the operation frequency at that time as the operation frequency command value. The method of claim 16, If the current operating frequency is not decreasing, continue to decrease the operating frequency, And when the sum of the product of the current integral and the stroke multiplied for one period is maximum, determining the operation frequency at that time as the operation frequency command value.

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