KR100393807B1 - Driving comtrol apparatus for reciprocating compressor - Google Patents

Abstract

The present invention relates to an operation control apparatus and a method of a reciprocating compressor, and to detect the load by the voltage applied to both ends of the switching element of the reciprocating compressor to control the stroke in accordance with the load to enable the optimum operation. To this end, the present invention includes a detection means for detecting the voltage across the switching element as a load; Control means for determining a stroke command value according to the magnitude of the load detected by said detection means, and outputting a switching control signal corresponding to the stroke command value; And a driving means for interrupting the AC power supply to the switching element by the switching control signal output from the control means and applying a predetermined voltage for driving the motor.

Description

Operation control apparatus and method of reciprocating compressor {DRIVING COMTROL APPARATUS FOR RECIPROCATING COMPRESSOR}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reciprocating compressor, and more particularly, to an operation control apparatus and a method of a reciprocating compressor for detecting a load by a voltage across a switching element.

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.

If the specific excitation state is not changed, the rotor can be stopped at a predetermined position, and various drive control that can generate reverse power by controlling the phase of the input pulse signal applied to the switching element based on the maximum inductance shape. As is possible, it is applied to electronic products requiring direction control.

In particular, the reciprocating compressor used in the refrigerator or the air conditioner can vary the compression ratio by the voltage applied to the motor, and thus has the advantage of controlling the cooling power according to the user's intention. It will be described in detail with reference to one drawing.

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 electrical 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.

However, since the reciprocating compressor operating as described above has a nonlinearity in which the mechanical motion characteristics are severe, there is a problem that precise control is impossible with a linear control method that does not take into account the nonlinearity.

In order to solve this problem, the optimum operation condition of the reciprocating compressor is detected by TDC = 0 and the operation is controlled by the switching control signal at the point to improve the operation efficiency. When the compressor is continuously operated for a predetermined time, there is a problem that the position of the piston is out of TDC = 0 due to the load change caused by the change in mechanical characteristics and the surrounding environment.

The present invention has been made to solve the above problems, the reciprocating compressor to detect the load by the voltage across the switching element of the reciprocating compressor and to operate optimally by automatically varying the stroke according to the load Its purpose is to provide an operation control apparatus and method of the.

1 is a circuit diagram showing a configuration for the operation control apparatus of a general reciprocating compressor.

Figure 2 is a circuit diagram showing a configuration for the operation control device of the reciprocating compressor of the present invention.

Figure 3 shows the minimum stroke size in Figure 2 for the cooling capacity required for each load.

4 is a vector diagram showing the magnitude of the voltage across the switching in accordance with the magnitude of the load in FIG.

5 is a view showing a state in which the switching limit voltage is set according to the load and the voltage across the switching in FIG.

6 is a view showing a state in which the switching limit voltage is set in accordance with the stroke and switching both ends voltage in FIG.

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

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

100: electrical circuit part 200: load detection part

300: control unit 301: stroke detection unit

302: comparator 303: stroke control unit

The present invention for achieving the above object, the detection means for detecting the voltage across the switching element as a load; Control means for determining a stroke command value according to the magnitude of the load detected by said detection means, and outputting a switching control signal corresponding to the stroke command value; And a driving means for interrupting the AC power to the switching element by the switching control signal output from the control means and applying a predetermined voltage for driving the motor.

The present invention for achieving the above object, the first step of inputting a stroke command value, and comparing the voltage across the switching element with the switching limit voltage; A second step of checking a limit check bit and setting a stroke command value according to the limit check bit value when the voltage between the switching element exceeds the switching element limit voltage as a result of the comparison of the first step; As a result of the comparison of the first step, if the voltage across the switching element does not exceed the switching limit voltage, the stroke command value is increased and if the same as the limit stroke command value, the limit stroke command value is set as the stroke command value. It is characterized by.

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.

Fig. 2 is a block diagram showing an embodiment of the operation control apparatus of the reciprocating compressor of the present invention, and as shown therein, a load detection unit 200 for detecting a voltage across the triac Tr1 as a load; A control unit (300) for determining a stroke command value based on the magnitude of the load detected by the load detection unit (200) and outputting a switching control signal according to the stroke command value; By the switching control signal output from the controller 300, the AC power is interrupted to the triac Tr1, and the electric circuit unit 100 is applied to apply a predetermined voltage for driving the motor M.

The control unit 300 includes a stroke detection unit 301 for detecting a current motor stroke; A comparator 302 for comparing the stroke command value with the magnitude of the current motor stroke and outputting a difference value accordingly; The stroke controller 303 outputs a switching control signal for controlling the stroke in accordance with the difference value output from the comparator 302.

7 is an operation flowchart of the operation control method of the reciprocating compressor according to the present invention, after inputting a stroke command value as shown therein, a first process of comparing the voltages between both ends of the triac Tr1 with the switching limit voltage; A second step of checking a limit check bit and setting a stroke command value according to the limit check bit value when the voltage between both ends exceeds the switching limit voltage as a result of the comparison of the first step; As a result of the comparison of the first process, if the voltage at both ends does not exceed the switching threshold voltage, the stroke command value is increased, and if it matches the threshold stroke command value, the third stroke is set as the stroke command value. The same 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 the voltage at both ends of the triac Tr1 as a load, drives the motor M by controlling a stroke according to the load, that is, the load detection unit 200 is connected at both ends of the triac Tr1. The applied voltage is detected as a load and applied to the controller 300.

Then, the control unit 300 determines the stroke command value according to the load output from the load detection unit 200 and applies the switching control signal according to the triac Tr1 of the electric circuit unit 100.

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.

Here, when the operation of the control unit 300 will be described in detail, the stroke detection unit 301 detects the current stroke of the motor M and applies it to the comparator 302.

Then, the comparator 302 compares the stroke command value according to the current load with the stroke and outputs a difference value according to the current load, and the stroke control unit 303 controls the stroke according to the difference value output from the comparator 302. The switching control signal is applied to the triac Tr1 of the electric circuit unit 100.

Accordingly, the electric circuit unit 100 adjusts the on / off time of the AC power by the switching control signal and applies a predetermined voltage to the motor M accordingly.

At this time, the control unit 300 determines the stroke command value in proportion to the magnitude of the load as shown in FIG.

Here, the following equation is for obtaining the voltage across the switching,

Voltage across switching = Power supply voltage-Voltage across capacitor-Back EMF

= 220 (V)-

At this time, Figure 4 is a vector diagram showing the magnitude of the voltage across the switching according to the load, according to the above equation, Figure 5 is a diagram showing the state of setting the switching threshold voltage in accordance with the load and the voltage across the switching.

That is, as shown in FIG. 6, the switching limit voltage is set to a value smaller than the internal withstand voltage and larger than the voltage between both ends of the triac Tr1. For example, the cooling capacity is sufficient when operating at the stroke size of S1 under the load # 1 condition. Set the switching limit voltage to

Referring to Fig. 7, the method for determining the stroke command value of the present invention will be described. First, after inputting a predetermined stroke command value, the voltage between both ends of the triac Tr1 is compared with the switching limit voltage, i.e., The maximum voltage across the evil Tr1 is compared with the positive switching limit voltage, and the minimum voltage across the triac Tr1 is compared with the negative switching limit voltage.

As a result of the comparison, when the voltage across the triac Tr1 exceeds the switching limit voltage, the limit check bit is checked and the stroke command value is set according to the limit check bit value.

That is, it is determined whether the limit check bit is set to '1'. If the limit check bit is not set to '1', the stroke command value is set to the limit stroke command value, and then the limit check bit is set to '1'. Decreases the stroke setpoint, which initializes the timer.

On the other hand, if the limit check bit is set to '1', the timer is initialized while decreasing the stroke command value.

Here, the limit check bit is set to '1' when the switching limit voltage is generated, and is set to '0' when it is out of the switching limit voltage.

As a result of the comparison, if the voltage between the both ends of the triac Tr1 does not exceed the switching limit voltage, the stroke command value is increased and, if it matches the limit stroke command value, the limit stroke command value is set as the stroke command value.

In other words, the present invention automatically performs variable cooling power control by detecting the voltage across the switching element as a load and then determining the stroke command value according to the load.

As described in detail above, the present invention has the effect of optimizing the operation of the reciprocating compressor by detecting the load with the voltage across the switching element of the reciprocating compressor and controlling the stroke according to the load.

Claims (13)

Detection means for detecting a voltage across the switching element as a load; Control means for determining a stroke command value according to the magnitude of the load detected by said detection means, and outputting a switching control signal corresponding to the stroke command value; And driving means for interrupting the AC power supply to the switching element by the switching control signal output from the control means and applying a predetermined voltage for driving the motor. The method of claim 1, wherein the control means, And a piston speed command value is determined according to the detected load magnitude, and a switching control signal corresponding to the speed command value is output. The method of claim 1, wherein the control means, And a piston acceleration command value is determined according to the magnitude of the detected load, and a switching control signal corresponding to the acceleration command value is output. The method of claim 1, wherein the control means, A piston TDC (Top Dead Center) command value is determined according to the detected load magnitude, and the operation control apparatus of the reciprocating compressor characterized by outputting a switching control signal corresponding to the TDC command value. The method of claim 1, wherein the control means, An operation control apparatus for a reciprocating compressor, characterized in that the stroke command value is determined in proportion to the magnitude of the load. The control means according to any one of claims 1 to 5, Detection means for detecting a current piston stroke; Comparison means for comparing the stroke command value with the magnitude of the current piston stroke and outputting a difference value accordingly; And a switching control means for outputting a switching control signal for controlling the stroke in accordance with the difference value output from the comparing means. The operation control apparatus for a reciprocating compressor according to claim 1, wherein the switching means sets the switching element limit voltage to a value less than its withstand voltage and greater than a voltage at both ends of the switching element. A first step of inputting a stroke command value and comparing a voltage between both ends of the switching element with a switching limit voltage; A second step of checking a limit check bit and setting a stroke command value according to the limit check bit value when the voltage between both ends exceeds the switching limit voltage as a result of the comparison of the first step; As a result of the comparison of the first process, if the voltage at both ends does not exceed the switching threshold voltage, the stroke command value is increased, and if the threshold stroke command value is matched, the threshold stroke command value is set as the stroke command value. Operation control method of a reciprocating compressor. 9. The method of claim 8, wherein the first step comprises: comparing a maximum voltage across the switching element with a positive switching limit voltage; Comprising the step of comparing the minimum voltage across the switching element with the negative switching limit voltage operation control method of a reciprocating compressor. The method of claim 8, wherein the limit check bit is set to '1' when a switching limit voltage is generated and to '0' when it is out of the switching limit voltage. 9. The method of claim 8, wherein the second process comprises: a first step of determining whether the limit check bit is set to '1'; As a result of the determination in the first step, if the limit check bit is not set to '1', the stroke command value is set to the limit stroke command value, and then the stroke check value is reduced to the second step while the limit check bit is set to '1'. Operation control method of the reciprocating compressor, characterized in that made. 12. The method of claim 11, wherein the second step includes initializing the timer to '0'. 12. The operation control method according to claim 11, further comprising the step of resetting the timer while reducing the stroke command value if the limit check bit is set to '1'.