KR20050050969A - Driving control apparatus and method for reciprocating compressor - Google Patents

Abstract

The present invention relates to an operation control apparatus and a method of a reciprocating compressor, in order to match the operating frequency to the mechanical resonance frequency at each load change, the operating frequency variable constant, the current, or one week when the stroke for one period is the maximum By detecting the current when the stroke is minimum during the period, and detecting the operating frequency at which the current is close to '0' as the operating frequency command value, 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 stroke detector for detecting a stroke of the compressor; A driving frequency variable constant calculating unit configured to receive a current output from the current detection unit and a stroke output from the stroke detection unit, and calculate a current when the stroke for one period is maximum as an operating frequency variable constant; An operating frequency command value generator for comparing the magnitude of the operating frequency variable constant with '0 ± δ' and generating an operating frequency command value based on the comparison result; And a controller for comparing the operation frequency command value with the current operation frequency and variably controlling the operation frequency of the reciprocating compressor accordingly.

Description

Operation Control System and Method of Reciprocating Compressor {DRIVING CONTROL APPARATUS AND METHOD FOR RECIPROCATING COMPRESSOR}

The present invention relates to an operation control apparatus and a method of a reciprocating compressor, in particular, in order to match the operating frequency to the mechanical resonance frequency at every load change, the operating frequency variable constant, the current when the stroke for one period is the maximum, or An operating control device for a reciprocating compressor that detects a current when the stroke for a period is minimum and detects an operating frequency whose current is close to '0' as an operating frequency command value, thereby improving the operating efficiency of the compressor. And to a method.

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: counter electromotive force

Accordingly, the comparator 1 compares the stroke estimate and 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.

At this time, the reciprocating compressor described above, as shown in Figure 3, the operation efficiency of the compressor is the best when operating at the mechanical resonance frequency, the conventional reciprocating compressor operation control method, the mechanical resonance according to the variable load Even if the frequency is variable, since the stroke is always controlled at a constant frequency without a change in the operating frequency, there is a problem that the operating efficiency of the compressor is lowered.

The present invention has been made to solve the above problems, in order to match the operating frequency to the mechanical resonant frequency at each load variable, the operating frequency variable constant, the current or one cycle when the stroke for one period is the maximum The operation control device and method of the reciprocating compressor which detects the current when the stroke is minimum and detects the operation frequency whose current is close to '0' as the operation frequency command value, thereby improving the operation efficiency of the compressor. The purpose is to provide.

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 stroke detector for detecting a stroke of the compressor; A driving frequency variable constant calculating unit configured to receive a current output from the current detection unit and a stroke output from the stroke detection unit, and calculate a current when the stroke for one period is maximum as an operating frequency variable constant; An operating frequency command value generator for comparing the magnitude of the operating frequency variable constant with '0 ± δ' and generating an operating frequency command value based on the comparison result; And a controller configured to compare the operation frequency command value with the current operation frequency and to variably control the operation frequency of the reciprocating compressor.

The present invention for achieving the above object, the process of detecting a current and a stroke applied to the compressor at regular intervals; Detecting a current when the detected stroke is the maximum for one period and calculating the current as an operating frequency variable constant; The operation frequency variable constant is compared with '0 ± δ', and the operation frequency command value is generated by subtracting or subtracting the current operation frequency based on the comparison result, and then driving the compressor using the operation frequency command value. do.

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.

First, as shown in Fig. 6, the present invention has a mechanical resonance frequency at a point where the current when the stroke for one cycle is minimum or the current when the stroke for one cycle is maximum is '0'. It is to be noted that attention was paid.

Figure 4 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. 4, the present invention includes a current detector 40 for detecting a current applied to the compressor L.comp; A stroke detection unit 30 for detecting a stroke of the compressor L.comp; A driving frequency variable constant calculating unit configured to receive a current output from the current detector 40 and a stroke output from the stroke detection unit 30, and calculate a current when the stroke for one period is maximum as an operating frequency variable constant ( 50); An operating frequency command value generator 60 for comparing the magnitude of the operating frequency variable constant with '0 ± δ' and generating an operating frequency command value based on the comparison result; A first comparator (10) for comparing the operation frequency command value with the current operation frequency and outputting a difference value accordingly; A second comparator (70) for comparing the stroke output from the stroke detection unit (30) with the stroke command value and outputting a difference value according thereto; The operating frequency of the compressor (L.comp) is varied according to the difference value output from the first comparator 10, and applied to the compressor (L.comp) according to the difference value output from the second comparator 70. The controller 20 is configured to control the stroke by varying the voltage.

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 comprises the steps of detecting currents and strokes applied to the compressor L.comp at regular intervals (SP1, SP2); Detecting a current when the stroke detected in the above is the maximum for one period and calculating the current as a driving frequency variable constant (SP3); Comparing the operation frequency variable constant with '0 ± δ', and based on the comparison result, the operation frequency command value is generated by adding or subtracting the current operation frequency, and then driving the compressor using the operation frequency command value (SP4 to SP7). The operation of the present invention will be described.

First, the current detector 40 detects a current applied to the compressor L.comp, and the stroke detector 30 detects a stroke of the compressor L.comp.

In this case, the second comparator 70 compares the stroke command value with the stroke output from the stroke detection unit 30 and applies the difference value to the controller 20 accordingly, and the controller 20 according to the difference value accordingly. The stroke is controlled by varying the voltage applied to the compressor (L.comp).

In addition, the controller 20 controls the TDC by comparing the current TDC with the TDC command value and changing the voltage applied to the compressor L.comp accordingly.

On the other hand, the driving frequency variable constant calculating unit 50 receives the current output from the current detector 40 and the stroke output from the stroke detector 30 to operate the current when the stroke for one period is the maximum. Calculate with frequency variable constant.

The operating frequency variable constant may be calculated by calculating the current when the stroke for one cycle is minimum as the operating frequency variable constant, or at the current when the stroke for one cycle is minimum, the stroke for one cycle is maximum. In this case, the current is subtracted and the subtracted value is calculated as the operating frequency variable constant.

 Thereafter, the driving frequency command value generation unit 60 compares the magnitude of the driving frequency variable constant output from the driving frequency variable constant calculating unit 50 with '0 ± δ' and based on the comparison result, the driving frequency command value. Occurs.

That is, as shown in FIG. 7, if the magnitude of the driving frequency variable constant is a value within '0 ± δ', the current driving frequency is generated as the driving frequency command value without frequency variation, and the magnitude of the driving frequency variable constant is “0”. If the value is greater than + δ ', the current operating frequency is increased by a predetermined level, and the increased operating frequency is generated as the operating frequency command value.If the magnitude of the operating frequency variable constant is smaller than' 0-δ ', the current operating frequency is increased by the predetermined level. Reduce and generate the reduced operating frequency as the operating frequency setpoint.

Here, FIG. 8 subtracts the current when the stroke during the one cycle is the minimum and the current when the stroke during the one cycle is the maximum and compares the subtracted value with '0 ± δ' to increase or decrease the operating frequency. This is a waveform diagram showing the state.

At this time, the upper and lower limit values (± δ) of the frequency non-variable region are set in proportion to the maximum stroke value during one period.

Subsequently, the first comparator 10 compares the operation frequency command value with the current operation frequency and applies a difference value to the controller 20, whereby the controller 20 at the first comparator 10. The operating frequency of the compressor (L.comp) is varied according to the difference value output.

In more detail, the present invention will be described with reference to Fig. 5, first, the current and the stroke applied to the compressor L.comp are detected at regular intervals (SP1 and SP2).

Then, the operating frequency variable constant is calculated using the detected current and stroke (SP3), that is, the current when the stroke for one period is maximum is calculated as the operating frequency variable constant.

Then, the operating frequency variable constant is compared with '0 ± δ' (SP4, SP6), and the operating frequency command value is generated by subtracting or subtracting the current operating frequency based on the comparison result (SP5, SP7). The compressor (L.comp) is driven with the frequency command value.

At this time, if the magnitude of the operating frequency variable constant is a value within '0 ± δ', the current operating frequency is generated as the operating frequency command value without changing the frequency, and if the magnitude of the driving frequency variable constant is larger than '0 + δ', The operating frequency is increased by a predetermined level, and the increased operating frequency is generated as the operating frequency command value. If the magnitude of the operating frequency variable constant is smaller than '0-δ', the current operating frequency is decreased by a predetermined level and the reduced operation is performed. Generates the frequency as the operating frequency setpoint.

9 and 10 are operation flow charts of another embodiment of the operation control method of the reciprocating compressor according to the present invention, and FIG. 9 uses a current when the stroke for one cycle has a minimum operating frequency variable constant, and FIG. 10 subtracts the operating frequency variable constant from the current when the stroke for one period is maximum and the current when the stroke for one period is minimum and uses the subtracted 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, in order to match the operating frequency to the mechanical resonance frequency at every load variation, the present invention uses a variable operating frequency constant to minimize the current or stroke for one cycle. By detecting the current in one case and detecting the operating frequency at which the current is close to '0' as the operating frequency command value, there is an effect of improving the operating efficiency of the 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.

3 is a diagram showing the relationship between mechanical resonance frequency and compressor efficiency in FIG.

Figure 4 is a block diagram showing the configuration of the operation control device of the reciprocating compressor of the present invention.

5 is an operation flow chart for the operation control method of the reciprocating compressor of the present invention.

FIG. 6 is a diagram showing a relationship between an operating frequency variable and compressor efficiency in FIG. 4; FIG.

FIG. 7 is a diagram showing the magnitude of the driving frequency according to the magnitude of the driving frequency variable in FIG. 4; FIG.

Fig. 8 is a waveform diagram showing the state in which the operating frequency is added to or subtracted from the current when the stroke for one cycle is minimum and the current subtracted when the stroke for one cycle is maximum to '0 ± δ'. ,

Figure 9 is a flow chart of another embodiment of the operation control method of the reciprocating compressor of the present invention.

Figure 10 is a flow chart of another embodiment of the operation control method of the reciprocating compressor of the present invention.

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

10,70: Comparator 20: Controller

30: stroke detection unit 40: current detection unit

50: operation frequency variable constant calculation unit 60: operation frequency command value generator

Claims (13)

In a reciprocating compressor, A current detector for detecting a current applied to the compressor; A stroke detector for detecting a stroke of the compressor; An operating frequency variable constant calculator configured to receive a current output from the current detector and a stroke output from the stroke detector, and calculate a stroke when the current for one period is maximum as an operating frequency variable constant; An operating frequency command value generator for comparing the magnitude of the operating frequency variable constant with '0 ± δ' and generating an operating frequency command value based on the comparison result; And a controller for comparing the operation frequency command value with the current operation frequency and variably controlling the operation frequency of the reciprocating compressor. The method of claim 1 wherein the controller is And a stroke controlled by comparing a stroke output from the stroke detection unit with a stroke command value, thereby controlling a stroke by varying a voltage applied to the compressor. The method of claim 1, wherein the controller, Comparing the current TDC and the TDC command value and controlling the TDC by varying the voltage applied to the compressor according to the operation control device of the reciprocating compressor. According to claim 1, wherein the operating frequency variable constant calculating unit An operation control apparatus for a reciprocating compressor, characterized in that for calculating a stroke when the current for one cycle is minimum as a variable operating frequency. The driving frequency variable constant calculating unit of claim 1, Operating stroke control device for a reciprocating compressor characterized by subtracting the stroke when the current during one cycle is the maximum and calculating the subtracted value as the operating frequency variable constant from the stroke when the current during one cycle is minimum. . The driving frequency command value generating unit according to claim 1, If the magnitude of the operating frequency variable constant is a value within '0 ± δ', the operation control device for a reciprocating compressor, characterized in that to generate the current operating frequency as the operating frequency command value without changing the frequency. The driving frequency command value generating unit according to claim 1, And a driving frequency variable constant greater than " 0 + δ " to increase the current operating frequency by a predetermined level and to generate the increased operating frequency as an operating frequency command value. The driving frequency command value generating unit according to claim 1, And a driving frequency variable is smaller than '0-δ', thereby reducing the current operating frequency by a predetermined level and generating the reduced operating frequency as an operating frequency command value. 9. An operation control apparatus for a reciprocating compressor according to any one of claims 6 to 8, wherein? Is set in proportion to the maximum stroke value during one cycle. Detecting a current and a stroke applied to the compressor at regular intervals; Detecting a stroke when the current detected above is the maximum for one period and calculating the stroke as an operating frequency variable constant; The operation frequency variable constant is compared with '0 ± δ', and the operation frequency command value is generated by subtracting or subtracting the current operation frequency based on the comparison result, and then driving the compressor using the operation frequency command value. Operation control method of a reciprocating compressor. The method of claim 12, wherein the operating frequency variable constant, An operation control apparatus for a reciprocating compressor, characterized in that for calculating a stroke when the current for one cycle is minimum as a variable operating frequency. The method of claim 12, wherein the operating frequency variable constant, Operation control method of a reciprocating compressor characterized by subtracting the stroke when the current during one period is the maximum and calculating the subtracted value as a variable operating frequency constant in the stroke when the current during one period is the minimum. . The process of claim 11, wherein the operating frequency variable constant is compared with '0 ± δ' and the compressor is operated by adding or subtracting the current operating frequency based on the comparison result. Generating a current operating frequency as an operating frequency command value without changing the frequency when the magnitude of the driving frequency variable constant is a value within '0 ± δ'; If the magnitude of the driving frequency variable constant is greater than '0 + δ', increasing the current driving frequency by a predetermined level and generating the increased driving frequency as a driving frequency command value; If the magnitude of the operating frequency variable constant is smaller than '0-δ', reducing the current operating frequency by a predetermined level and generating the reduced operating frequency as the operating frequency command value. Control method.