KR20050115807A - Reciprocating compressor, drive device of reciprocating compressor and control medhod of reciprocating compressor - Google Patents

Abstract

The present invention relates to a driving device and a control method of a reciprocating compressor, and in particular, the efficiency is improved under normal load, and the efficiency is improved by controlling the frequency of the input power source so as to follow the resonant frequency in which the operating frequency of the compressor is changed according to the load variation. It would be possible. The reciprocating compressor according to the present invention includes an inverter for adjusting the input power frequency, the resonance frequency of the reciprocating compressor is set within the range of 60 ~ 90% of the commercial power frequency, the input power frequency corresponding to the resonance frequency by the inverter It is set to the frequency. In addition, the present invention includes a control unit for controlling the input power frequency so that the operating frequency of the reciprocating compressor follows the resonance frequency that changes according to the operation of the reciprocating compressor.

Description

Reciprocating compressor, reciprocating compressor drive system and reciprocating compressor control method {RECIPROCATING COMPRESSOR, DRIVE DEVICE OF RECIPROCATING COMPRESSOR AND CONTROL MEDHOD OF RECIPROCATING COMPRESSOR}

The present invention relates to a reciprocating compressor, and more particularly, to improve efficiency at a general low load, and to improve efficiency by controlling a frequency of an input power source so as to follow a resonant frequency in which the operating frequency of the compressor varies with load fluctuations. The present invention relates to a driving device and a control method of a reciprocating compressor.

In general, among compressors used for compressing refrigerant in equipment such as an air conditioner or a refrigerator, there is a reciprocating compressor that compresses the refrigerant by causing the volume of the compression chamber to change due to the retraction of the piston. In addition, reciprocating compressors include a method of employing a rotary motor as a driving means and a method of employing a general linear motor.

Among these reciprocating compressors, a reciprocating compressor employing a conventional linear motor is directly connected to a mover of a linear motor in which a piston moving in and out of the compression chamber has a linear motion. The piston is supported by an elastic resonant spring. When the AC power is applied to the linear motor, the reciprocating compressor compresses the refrigerant by moving the piston in and out according to the frequency of the input power. At this time, the resonant spring exerts an excitation force to increase the kinetic force of the piston and at the same time smoothly retreat.

In addition, the conventional reciprocating compressor is a resonance frequency (intrinsic frequency) of the compressor and the operating frequency of the piston coincide with the increase of the kinetic force when the resonance occurs, the compression efficiency is improved. Therefore, conventionally, the efficiency of the compressor has been improved by setting the frequency of the commercial power source and the resonance frequency of the compressor to coincide. In other words, by adjusting the resonant frequency so that the resonant frequency corresponds to the frequency of the commercial power source to improve the compression capacity. Since the resonant frequency of the compressor is determined by the mass of the movable part including the piston and the mover of the linear motor, the elastic force of the resonant spring, and the like, it can be adjusted by changing these conditions.

However, since the conventional reciprocating compressor used the high frequency commercial power (typically 60 Hz) as the input power while the resonant frequency was matched with the frequency of the commercial power supply, the operating speed was fast and the compressor variable range was extended to a lower range. Not only was there a problem difficult to do, but there was a drawback of low efficiency due to iron loss and mechanical friction loss of the motor.

In addition, the reciprocating compressor may change the resonant frequency due to the pressure change of the gas applied to the piston when the load is changed during the operation of the compressor, the mismatch between the resonant frequency and the operating frequency due to the change of the resonant frequency There was a drawback that the efficiency is lowered.

The present invention is to solve such a problem, an object of the present invention is to set the resonant frequency of the compressor lower than the frequency of the commercial power source, and the input power frequency of the compressor to correspond to the resonant frequency to more than the variable capacity range of the compressor It is possible to provide a driving device and a control method of a reciprocating compressor which can be expanded to a low range and improve efficiency by performing resonance in a range lower than a frequency of a commercial power source.

It is another object of the present invention to provide a driving device and a control method of a reciprocating compressor that can improve the efficiency of the compressor by allowing the compressor to follow the resonant frequency that is changed according to the load change.

The reciprocating compressor according to the present invention for achieving the object, in the reciprocating compressor including an inverter for adjusting the input power frequency, the resonant frequency of the reciprocating compressor is set lower than the commercial power frequency, the input power of the reciprocating compressor A frequency is set by the inverter to a frequency corresponding to the resonance frequency.

In addition, the resonance frequency is characterized in that it is set in the range of 60 ~ 90% of the commercial power frequency.

In another aspect, the present invention includes a control unit for controlling the operation of the reciprocating compressor, wherein the control unit controls the input power frequency so that the operating frequency of the reciprocating compressor follows the resonant frequency that changes according to the operation of the reciprocating compressor. do.

The control unit may determine a phase difference between the input power frequency and the operating frequency of the reciprocating compressor, and control to increase or decrease the input power frequency with a correction value corresponding to the phase difference.

In another aspect, the present invention includes a current detection unit for detecting the frequency of the power applied to the reciprocating compressor from the inverter, and a displacement detection unit for detecting the moving frequency by detecting the retraction range of the piston provided in the reciprocating compressor. It is done.

In addition, the present invention includes a load detection unit for detecting the load of the reciprocating compressor, the control unit controls the inverter so that the input power frequency is equal to the resonant frequency when the load detected through the load detection unit is a normal load When the detected load is a high load, the inverter is controlled such that the input power frequency is higher than the resonance frequency.

In addition, the reciprocating compressor according to the present invention is a reciprocating compressor including an inverter for adjusting the input power frequency, the operating frequency and the input power frequency is the same by detecting the phase difference between the operating frequency and the input power frequency of the reciprocating compressor It characterized in that it comprises a control unit for controlling the inverter to lose.

In addition, the driving device of the reciprocating compressor according to the present invention includes an inverter for adjusting an input power frequency applied to the reciprocating compressor, a load detecting unit for detecting a load of the reciprocating compressor, and a load detected through the load detecting unit is a general load. And a controller for controlling the inverter so that an input power frequency is equal to the resonance frequency of the reciprocating compressor, and controlling the inverter such that the input power frequency is higher than the resonance frequency when the detected load is a high load. It is done.

In addition, the driving device of the reciprocating compressor according to the present invention detects the retraction range of the piston provided in the inverter for adjusting the input power frequency applied to the reciprocating compressor, the current detection unit for detecting the input power frequency, and the reciprocating compressor A displacement detection unit for detecting an operating frequency and a phase difference between the input power frequency and the operating frequency in order to follow the resonance frequency that is changed according to the operation of the reciprocating compressor, and then the input power frequency based on the phase difference. It characterized in that it comprises a control unit for controlling the inverter to increase or decrease.

In addition, the control method of the reciprocating compressor according to the present invention determines whether the load of the reciprocating compressor is a high load or a general load; When the load of the reciprocating compressor is a normal load, applying a power source having a frequency equal to the resonance frequency of the reciprocating compressor to the reciprocating compressor; When the load of the reciprocating compressor is a high load, it is characterized in that for applying the power of a frequency higher than the resonance frequency of the reciprocating compressor to the reciprocating compressor.

In addition, the control method of the reciprocating compressor according to the present invention includes a control method of a reciprocating compressor having an inverter, comprising: determining a phase difference between an input power frequency and an operating frequency of the reciprocating compressor; And control the inverter to increase or decrease the input power frequency by a correction value corresponding to the phase difference.

Hereinafter, with reference to the accompanying drawings a preferred embodiment according to the present invention will be described in detail.

As illustrated in FIG. 1, the reciprocating compressor according to the present invention includes a sealed container 10 formed by combining an upper container 10a and a lower container 10b. And it is installed in the sealed container 10, the compression device 20 including the cylinder block 21, the piston 22, the cylinder head 23, and the drive means for driving the compression device 20 In addition, the linear motor 30 including the movable member 31 and the inner and outer stators 32 and 33 is provided. The compression device 20 and the linear motor 30 inside the sealed container 10 are configured to form a set.

The cylinder block 21 of the compression device 20 has a cylinder portion 21a which forms the compression chamber 24 and an outer stator of the linear motor 30 extending outward from the lower circumference of the cylinder portion 21a. And a support 21b for supporting 33. The cylinder block 21 is supported by the lower end of the support portion 21b spaced apart from the inner surface of the lower container 10b through the plurality of buffer members 25.

The piston 22 is installed in the compression chamber 24 of the cylinder block 21 to be able to move up and down. The cylinder head 23 includes a suction chamber 23a and a discharge chamber 23b and is installed at the lower end of the cylinder block 21. In addition, an inlet port 23c having a suction valve plate is formed at the suction chamber 23a side of the cylinder head 23, and a discharge port 23d having a discharge valve plate is provided at the discharge chamber 23b side of the cylinder head 23. Is formed. In FIG. 1, reference numeral 11 denotes an external suction pipe, reference numeral 12 denotes a suction tube connected to the suction chamber 23a, and reference numeral 13 denotes a discharge pipe extending to the outside of the sealed container 10 and connected to the discharge chamber 23b. .

In the linear motor 30 for operating the piston 22, the mover 31 and the inner and outer stators 32 and 33 are disposed outside the cylinder portion 21a. The mover 31 is provided in a cylindrical shape and the upper fixing portion 31a at the upper end thereof is coupled to the upper outer surface of the piston 22 so as to move up and down with the piston 22. In addition, the movable magnet 31 is coupled to the magnetized magnet 35 to move forward and backward through the interaction with the outer stator (33).

The inner stator 32 and the outer stator 33 are each provided in a cylindrical shape and are disposed inside and outside of the mover 31, respectively. The inner stator 32 is fixed to the outer surface of the cylinder portion 21a to guide the up and down movement of the mover 31 and at the same time the magnetic flux from the outer stator 33 to the magnet 35 of the mover 31. It functions to make the flow smooth. The outer stator 33 has an excitation coil 34 for electromagnetic interaction with the magnet 35 of the mover 31, the lower end of which is supported by the support 21b of the cylinder block 21 and the upper end of which is fixed. Supported through the frame 36.

In addition, the reciprocating compressor of the present invention is installed on the upper spaced apart from the fixed frame 36 and the mover 31, and includes a resonant spring 37 consisting of a layered leaf spring. The resonant spring 37 has a central portion coupled to the upper end of the piston 22, and an outer end portion thereof is coupled to a spring support 38 extending upward from the fixed frame 36. This allows the excitation force to be generated by the elasticity of the resonant spring 37 to improve the kinetic force of the piston 22.

On the upper side of the resonant spring 37, a sensor core 41 extending upward from the mover 31 by sensing the movement of the mover 31 and the piston 22, and of the sensor core 41, Coil-type displacement detection sensor 42 for detecting the forward and backward motion is installed.

The reciprocating compressor is a magnetic field is formed on the outer stator 32 when the AC power is applied to the excitation coil 34 of the outer stator 33, the polarity of the magnetic field is periodically changed, the magnet 35 is coupled to the mover Up and down of (31) is made. Then, as the mover 31 moves forward and backward, the piston 22 is moved forward and backward, and the suction and pressurized discharge of the refrigerant is performed by the forward and backward operation of the piston 22.

If the operating frequency of the piston 22 and the resonance frequency (intrinsic frequency) of the compressor coincide in the course of such a compression operation, resonance occurs and the kinetic force of the piston 22 and the mover 31 is increased, thereby improving efficiency. . Therefore, in the case of the conventional reciprocating compressor, the frequency of the commercial power supply and the resonance frequency of the compressor are set to match. However, the reciprocating compressor of the present invention sets the resonance frequency lower than the normal commercial power source frequency, and sets the frequency of the input power supplied to the reciprocating compressor to correspond to the resonance frequency lower than the commercial power source frequency.

For example, when the frequency of the commercial power source is 60 Hz, the resonance frequency of the compressor is set to about 50 Hz, and the input power frequency of the compressor is also about 50 Hz. At this time, if the resonance frequency and the input power frequency of the compressor are set too low, the efficiency may be deteriorated. Therefore, if the commercial power frequency is 60 Hz, the resonance frequency and the input power frequency are 35 to 55 Hz corresponding to 60 to 90% of the commercial power frequency. It is appropriate to set the degree.

This configuration is to improve the efficiency and at the same time to widen the range of compression capacity according to the load fluctuation of the cooling system employing such a compressor by expanding the capability variable range to a lower range than the conventional reciprocating compressor. In addition, it is possible to improve the overall compressor efficiency by increasing the efficiency at low speed operation of the normal low load (hereinafter referred to as "normal load"), which has a high operation ratio because resonance occurs in a range lower than the commercial power frequency. In addition, the compressor operates at a lower operating frequency than the commercial power frequency under normal load conditions, so that it may be advantageous in terms of iron loss of the motor or mechanical friction loss.

Figure 2 is a control block diagram showing the configuration of a drive device for the operation control of such a reciprocating compressor. As shown in the drawing, the driving apparatus includes an inverter 51 for adjusting the voltage and frequency of the power supplied from the commercial AC power source 50 to the reciprocating compressor, and a current detector for detecting the input power frequency through the current sensor 52. (53). In addition, the drive unit detects the displacement of the piston 22 and the mover 31 from the displacement detection sensor 42 inside the compressor to detect the operating frequency and the temperature of the compressor, the discharge and suction pressure, etc. A load detector 55 for detecting a load on the compressor by detecting a load of a cooling system employing a compressor, and a current detector 53, a displacement detector 54, and a load for controlling an input power frequency applied to the reciprocating compressor. And a controller 56 that controls the inverter 51 based on the information detected by the detector 55 or the like.

The following describes a control method for the compression operation and the efficient operation control of such a reciprocating compressor.

When the compressor is started, a power source (for example, a 60 Hz power source) applied from the commercial power source 50 to the reciprocating compressor is switched by the inverter 51 to a power source corresponding to the resonance frequency of the compressor. In other words, the input power frequency applied from the inverter 51 to the compressor is 50 Hz corresponding to the resonance frequency. Therefore, the compressor performs the compression operation while the piston 22 moves to the operating frequency of about 50 Hz in the normal load state (low load state), and the resonance occurs in a range lower than the commercial power frequency, so that the operation ratio is high. Higher efficiency can be achieved in operation.

In addition, during this operation, the controller 56 of the compressor determines whether the load applied to the compressor through the load detector 55 is a normal load or a high load. When the load of the compressor is a general load, the inverter 51 is controlled so that the input power is supplied at a frequency corresponding to the resonance frequency of the compressor.

In addition, when the operation is performed in the normal load state, the controller 56 controls the input power frequency to keep the resonance state continuously following the change in the resonant frequency that changes minutely according to the load change of the compressor, thereby showing the optimum efficiency. Be sure to That is, while the compressor is in operation, the mass of the movable part including the piston 22 and the mover 31 and the elasticity of the resonant spring are fixed, but the resonance pressure is changed because the pressure of the gas applied to the piston 22 changes as the load changes. The present invention allows the input power frequency to follow the change in the resonance frequency through the control of the controller 56 so that the efficiency can be further improved.

Such control is performed as shown in FIG. That is, the control for following the resonance frequency detects the operation frequency by detecting the displacement of the piston 22 through the displacement detection unit 54 (61), and detects the input power frequency through the current detection unit 53 (62), The controller 56 detects the phase difference between the operating frequency and the input power frequency based on these information (63). The controller 56 determines whether the detected phase difference is "0" or larger or smaller than "0" (64, 65). This is to determine the presence and magnitude of the phase difference. At this time, the compressor may be regarded as a resonance state when the input power frequency and the operating frequency are the same. Therefore, if the phase difference is "0", the controller 56 controls the inverter 51 to maintain the input power frequency as it is (66). If the phase difference is greater than "0", the inverter 51 is controlled to calculate the correction value corresponding to the phase difference to increase the input power frequency (67), and if the phase difference is smaller than "0", it is also equivalent to the phase difference. The inverter 51 is controlled (68) to reduce the input power frequency by calculating a correction value. As such, the controller 56 calculates a correction value based on the detection of the phase difference between the input power frequency and the operating frequency to control the input power frequency to increase or decrease, thereby changing the resonance frequency according to the load variation. Or the operating frequency) to follow the resonant frequency to achieve the best efficiency.

On the other hand, if it is determined that the load of the compressor detected by the load detector 55 is a high load higher than the normal load, the controller 56 may be applied to the compressor input power frequency higher than the resonance frequency to improve the capacity of the compressor. The inverter 51 is controlled so that it is controlled. That is, the reciprocating compressor according to the present invention maximizes the efficiency of the normal load by matching the resonance frequency and the input power frequency in the case of the normal load, and controls so that the sufficient compression capacity can be exhibited in the range where the efficiency is not significantly lowered in the case of the high load. . Such control is often operated in a normal load state as compared with a case in which a normal compressor is operated at a high load state, so that the efficiency of the overall compressor can be improved by maximizing the efficiency at a normal load state having a high operation ratio. will be.

As described in detail above, the reciprocating compressor according to the present invention sets the resonant frequency of the compressor lower than the frequency of the commercial power source, and the input power frequency of the compressor to correspond to the resonant frequency, so that the range of the variable capacity of the compressor lower range It can be expanded to, and the resonance is made in the range lower than the frequency of the commercial power supply has the effect that the efficiency can be improved. In particular, since the efficiency under normal load conditions with a high running ratio can be improved, the overall compressor efficiency can be improved.

In addition, the present invention is to improve the efficiency of the compressor to maintain the resonance state by controlling the input power frequency so that the operating frequency can follow the resonance frequency even if the resonance frequency changes due to the load change during the operation of the compressor There is an effect that can be further improved.

1 is a cross-sectional view showing a reciprocating compressor according to the present invention.

2 is a control block diagram showing the configuration of a drive system for a reciprocating compressor according to the present invention.

3 is a flowchart illustrating a control process of the reciprocating compressor according to the present invention.

Explanation of symbols on the main parts of the drawings

10: sealed container, 20: compression device,

30: linear motor, 42: displacement detection sensor,

50: commercial power, 51: inverter,

53: current detector, 54: displacement detector,

55: load detection unit, 56: control unit.

Claims (12)

In the reciprocating compressor including an inverter for adjusting the input power frequency, And the resonant frequency of the reciprocating compressor is set lower than the commercial power frequency, and the input power frequency of the reciprocating compressor is set to a frequency corresponding to the resonant frequency by the inverter. The method of claim 1, The resonant frequency is reciprocating compressor, characterized in that set in the range of 60 ~ 90% of the commercial power frequency. The method of claim 2, A control unit for operation control of the compressor; And the control unit controls the input power frequency such that the operating frequency of the reciprocating compressor follows the resonance frequency which changes according to the operation of the reciprocating compressor. The method of claim 3, And the control unit judges a phase difference between the input power frequency and the operating frequency of the reciprocating compressor, and controls to increase or decrease the input power frequency by a correction value corresponding to the phase difference. The method of claim 4, wherein And a current detection unit for detecting a frequency of power applied from the inverter to the reciprocating compressor, and a displacement detection unit for detecting the moving frequency by detecting a retraction range of the piston provided in the reciprocating compressor. . The method according to claim 3 or 5, It includes a load detection unit for detecting the load of the reciprocating compressor, The controller controls the inverter such that the input power frequency is equal to the resonance frequency when the load detected by the load detector is a normal load, and the input power frequency is higher than the resonance frequency when the detected load is a high load. A reciprocating compressor, characterized in that for controlling the inverter to increase. In the reciprocating compressor including an inverter for adjusting the input power frequency, And a control unit controlling the inverter such that the operating frequency and the input power frequency become the same by detecting a phase difference between the operating frequency and the input power frequency of the reciprocating compressor. The method of claim 7, wherein The control unit controls the inverter to increase or decrease the input power frequency by a correction value corresponding to the phase difference, so that the operating frequency finally follows the resonance frequency that changes according to the operation of the reciprocating compressor. Reciprocating compressor. In a driving device for driving a reciprocating compressor, An inverter for adjusting an input power frequency applied to the reciprocating compressor, a load detector for detecting a load of the reciprocating compressor, and a load detected through the load detector, the input power frequency being a resonance frequency of the reciprocating compressor. And a controller for controlling the inverter to be equal to the controller, and controlling the inverter such that the input power frequency is higher than the resonance frequency when the detected load is a high load. In a driving device for driving a reciprocating compressor, An inverter for adjusting an input power frequency applied to the reciprocating compressor, a current detecting unit for detecting the input power frequency, a displacement detecting unit for detecting an operating frequency by detecting an advancing range of a piston provided in the reciprocating compressor, and the movable unit A control unit for controlling the inverter to increase or decrease the input power frequency based on the phase difference after determining a phase difference between the input power frequency and the operating frequency so that a frequency follows a resonance frequency that changes according to the operation of the reciprocating compressor. Driving device for a reciprocating compressor, characterized in that it comprises a. In the control method of the reciprocating compressor, Determining whether the load of the reciprocating compressor is a high load or a general load; When the load of the reciprocating compressor is a normal load, applying a power source having a frequency equal to the resonance frequency of the reciprocating compressor to the reciprocating compressor; The control method of the reciprocating compressor, characterized in that when the load of the reciprocating compressor is a high load, a power of a frequency higher than the resonance frequency of the reciprocating compressor is applied to the reciprocating compressor. In the control method of a reciprocating compressor having an inverter, Determine a phase difference between an input power frequency and an operating frequency of the reciprocating compressor; And controlling the inverter to increase or decrease the input power frequency by a correction value corresponding to the phase difference.