JP2005344708A - Reciprocating compressor and its drive mechanism as well as control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reciprocating compressor drive mechanism and its control method for controlling the frequency of an input power source so that the operating frequency of a compressor follows a resonance frequency which is varied with a load fluctuation applied to the compressor. <P>SOLUTION: A reciprocating compressor has an inverter for adjusting the frequency of the input power source. The frequency of the input power source is set to be a value corresponding to the resonance frequency by the inverter. The resonance frequency is set to be a range of 60-90% of the frequency of a service power source. The reciprocating compressor according to this invention also has a control part for controlling the frequency of the input power source so that the operating frequency of the compressor follows the resonance frequency which is varied with the operation of the compressor. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a reciprocating compressor, and more specifically, controls the frequency of an input power source so that the operating frequency of the compressor becomes equal to a resonance frequency that varies based on a load variation applied to the compressor, In addition, the present invention relates to a reciprocating compressor drive device and control method that improve efficiency in a low load state.

  In general, compressors used in air conditioners, refrigerators, and the like to compress refrigerant include a reciprocating compressor that compresses refrigerant by causing a volume change of a compression chamber by reciprocating movement of a piston. Furthermore, this reciprocating compressor is classified into a type employing a rotary motor as a driving means and a type employing a normal linear motor.

  Especially, the reciprocating compressor which employ | adopts a normal linear motor is comprised so that the piston which reciprocates in a compression chamber may be directly connected with the needle | mover of the linear motor which carries out a linear motion. The piston is supported by an elastic resonance spring. In such a reciprocating compressor, when an AC power supply is applied to the linear motor, the mover linearly reciprocates according to the frequency of the input power supply, and the piston reciprocates due to the linear reciprocation of the mover to compress the refrigerant. Is made. Here, the resonance spring exhibits an excitation force that facilitates the movement of the piston and makes the reciprocating movement smooth.

  In a normal compressor, the movement of the piston increases when the resonance frequency (natural frequency) of the compressor and the operating frequency of the piston coincide with each other. Therefore, in order to improve the efficiency of the compressor, Attempts have been made to match the frequency of the compressor with the resonance frequency of the compressor. That is, in order to improve the compression capability of the compressor, it is important to adjust the resonance frequency of the compressor according to the normal power supply frequency. Since the resonance 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 resonance spring, and the like, it may be adjusted by changing these conditions.

  However, since such a conventional reciprocating compressor uses a high-frequency service power source (usually 60 Hz) as an input power source in a state where the resonance frequency matches the power frequency, the operating speed of the compressor is high. There is a drawback that it becomes faster, it becomes difficult to expand the variable range of the compressor capacity to a lower range, and the efficiency is reduced due to iron loss and mechanical friction loss of the motor.

  In addition, in a conventional reciprocating compressor, when the load fluctuates during the operation of the compressor, the resonance frequency may change due to a change in the pressure of the gas applied to the piston. There is also a disadvantage that the frequency is not consistent and the efficiency of the compressor is lowered.

  The present invention has been made in view of the above circumstances, and an object thereof is to set the resonance frequency of the compressor to be lower than the normal power supply frequency and to match the frequency of the input power supply applied to the compressor with the resonance frequency. Thus, in addition to further expanding the capacity variable range of the compressor, a reciprocating compressor drive device that improves the compressor efficiency by allowing the compressor to resonate in a frequency range lower than the frequency of the normal power supply, and It is to provide a control method.

  Another object of the present invention is to provide a reciprocating compressor capable of further improving the efficiency of the compressor by matching the operating frequency of the compressor with a resonance frequency that is variable based on a change in load applied to the compressor. It is in providing the drive device and control method of this.

  In order to achieve the above object, a reciprocating compressor according to the present invention is a reciprocating compressor having an inverter that receives power and adjusts the frequency of the received power to be input to the compressor. The resonance frequency is lower than the normal frequency of the received power supply, and the frequency of the input power supply corresponds to the resonance frequency.

  The resonance frequency is in a range of 60 to 90% of a normal frequency of the received power supply.

  In addition, the reciprocating compressor further includes a control unit that controls the operation of the compressor, and the control unit is configured so that an operating frequency of the compressor follows a resonance frequency that varies depending on the operation of the compressor. The frequency of the input power supply is controlled.

  Further, the control unit determines a phase difference between the frequency of the input power source and the operating frequency of the compressor, and increases or decreases the frequency of the input power source according to a correction value corresponding to the phase difference. It is characterized by controlling an inverter.

  The reciprocating compressor includes a piston installed in the compressor, a current detection unit that detects the frequency of the input power source, and a displacement detection unit that detects the displacement of the piston and determines the operating frequency. , And further.

  The reciprocating compressor further includes a load detection unit that detects a load applied to the compressor, and the control unit includes the input power source when the load detected by the load detection unit is a general load. The inverter is controlled so that the frequency of the power supply is equal to the resonance frequency, and when the detected load is higher than the general load, the inverter is controlled so that the input power supply frequency is higher than the resonance frequency. It is characterized by that.

  The reciprocating compressor according to the present invention includes an inverter that adjusts a frequency of a power source input to the compressor, and an operating frequency of the compressor between a determined operating frequency and a frequency of the input power source. And a control unit that controls the inverter so as to match the frequency of the input power supply based on a phase difference.

  The reciprocating compressor driving apparatus according to the present invention includes an inverter that adjusts a frequency of an input power supply applied to the compressor, a load detection unit that detects a load applied to the compressor, and the load detection. When the load detected by the unit is a general load, the inverter is controlled so that the frequency of the input power source is equal to the resonance frequency of the compressor, and when the detected load is larger than the general load, And a control unit that controls the inverter so that the frequency of the input power supply is higher than the resonance frequency.

  The reciprocating compressor driving device according to the present invention includes a piston, an inverter for adjusting a frequency of an input power source applied to the compressor, a current detecting unit for detecting the frequency of the input power source, and a displacement of the piston. A displacement detection unit that determines the operating frequency of the compressor by detecting the noise, and the operating frequency between the input power supply frequency and the operating frequency so that the operating frequency follows a resonance frequency that varies depending on the operation of the compressor. A control unit that determines a phase difference and controls the inverter to increase or decrease the frequency of the input power source based on the determined phase difference.

  The reciprocating compressor control method according to the present invention determines whether the load applied to the compressor is a high load or a general load, and when the load applied to the compressor is a general load, When a power source having the same frequency as the resonance frequency is applied to the compressor and the load applied to the compressor is a high load, a power source having a frequency higher than the resonance frequency of the reciprocating compressor is supplied to the compressor. It is characterized by applying.

  The reciprocating compressor control method according to the present invention is a reciprocating compressor control method having an inverter, wherein the phase difference between the frequency of the input power source and the operating frequency of the compressor is determined and corresponds to the phase difference. The inverter is controlled so as to increase or decrease the frequency of the input power supply according to the correction value.

  In the reciprocating compressor according to the present invention, the resonance frequency of the compressor is set lower than the frequency of the normal power supply, and the input power supply frequency of the compressor corresponds to the resonance frequency, so that the variable capacity range of the compressor is lower. It is possible to expand the range so that the compressor resonates in a frequency range lower than the frequency of the utility power supply, and as a result, the efficiency of the compressor can be improved. In particular, since the efficiency of the compressor in a general load state with a high operation ratio is improved, the highest compressor efficiency can be obtained.

  In addition, the present invention maintains the resonance state by controlling the frequency of the input power supply so that the operating frequency follows the change in the resonance frequency even when the resonance frequency changes due to the load fluctuation during the operation of the compressor. As a result, the efficiency of the compressor can be maximized.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  As shown in FIG. 1, the reciprocating compressor according to the present invention includes a hermetic container 10 in which an upper container 10a and a lower container 10b are combined. The reciprocating compressor includes a compression device 20 including a cylinder block 21, a piston 22 and a cylinder head 23, and driving means for driving the compression device 20, including a mover 31, an inner / outer stator 32, And a linear motor 30 including 33. The compression device 20 and the linear motor 30 are installed as one set inside the sealed container 10.

  The cylinder block 21 of the compression device 20 includes a cylinder portion 21 a that forms a compression chamber 24, and a support portion 21 b that extends outward from the lower outer periphery of the cylinder portion 21 a and supports the outer stator 33 of the linear motor 30. And including. The cylinder block 21 is supported in a state in which the lower end of the support portion 21b is separated from the inner surface of the lower container 10b via a plurality of buffer members 25.

  The piston 22 is installed in the compression chamber 24 of the cylinder block 21 so as to reciprocate up and down. The cylinder head 23 includes a suction chamber 23 a and a discharge chamber 23 b and is installed at the lower end of the cylinder block 21. A suction port 23c having a suction valve plate is formed on the suction chamber 23a side of the cylinder head 23, and a discharge port 23d having a discharge valve plate is formed on the discharge chamber 23b side of the cylinder head 23. Reference numeral 11 denotes an external suction pipe, 12 denotes a suction pipe connected to the suction chamber 23 a, and 13 denotes a discharge pipe connected to the discharge chamber 23 b side and extending to the outside of the sealed container 10.

  The linear motor 30 that operates the piston 22 is installed such that the mover 31 is disposed inside the cylinder portion 21a and the inner and outer stators 32 and 33 are disposed outside the cylinder portion 21a. The mover 31 has a cylindrical shape, and an upper fixed portion 31 a at the upper end thereof is coupled to the upper outer surface of the piston 22 so as to move linearly up and down together with the piston 22. Moreover, the needle | mover 31 has the magnet 35 attached to the lower end of the upper side fixing | fixed part 31a. The magnet 35 reciprocates the mover 31 up and down by the interaction with the outer stator 33.

  The inner stator 32 and the outer stator 33 each have a cylindrical shape, and are respectively disposed on the inner side and the outer side of the movable member 31. The inner stator 32 is fixed to the outer surface of the cylinder portion 21a and guides the reciprocating movement of the mover 31. At the same time, the inner stator 32 has a function of smoothing the flow of magnetic flux from the outer stator 33 through the magnet 35 of the mover 31. Bear. The outer stator 33 includes an exciting coil 34 for electromagnetic interaction with the magnet 35 of the mover 31, the lower end is supported by the support portion 21 b of the cylinder block 21, and the upper end is supported by the fixed frame 36.

  Further, the reciprocating compressor of the present invention is provided on the fixed frame 36 so as to be spaced upward from the mover 31 and includes a resonance spring 37 composed of multiple plate springs. The resonance spring 37 has a center portion coupled to the upper end of the piston 22 and an outer end portion coupled to a spring support portion 38 extending upward from the fixed frame 36. The resonance spring 37 improves the motion force of the piston 22 by generating an excitation force by its elasticity.

  Further, on the upper side of the resonance spring 37, a sensor core 41 extending upward from the movable element 31 and reciprocatingly following the reciprocating movement of the movable element 31 and the piston 22, and a movement distance of the sensor core 41 are detected. The displacement detection sensor 42 is installed.

  In the reciprocating compressor configured as described above, when an AC power is applied to the excitation coil 34 of the outer stator 33, a magnetic field is formed in the outer stator 32, and the polarity of the magnetic field changes periodically while the magnet is changed. The movable element 31 to which the 35 is coupled is reciprocated up and down. As the movable element 31 reciprocates, the piston 22 reciprocates to perform a compression operation, and refrigerant can be sucked and discharged.

  During this compression operation, when the operating frequency of the piston 22 matches the resonance frequency (natural frequency) of the compressor, the resonance of the compressor is performed, thereby increasing the kinetic force of the piston 22 and the mover 31 and compressing the compression. The efficiency of the machine is also improved. Therefore, the conventional reciprocating compressor has been controlled so that the normal power supply frequency matches the resonance frequency of the compressor. In contrast, in the reciprocating compressor of this embodiment, the resonance frequency of the compressor is set to a value lower than the normal power supply frequency, and the frequency of the input power supplied to the reciprocating compressor is the normal power supply frequency. Control is made so as to correspond to a lower resonance frequency.

  For example, when the normal power supply frequency is 60 Hz, the resonance frequency of the compressor is set to about 50 Hz, and the input power supply frequency of the compressor is also set to about 50 Hz. Here, if the resonance frequency of the compressor and the frequency of the input power supply are too low, the efficiency is rather lowered. Therefore, if the normal power supply frequency is 60 Hz, the resonance frequency and the frequency of the input power supply are 60 to 90 of the normal power supply frequency. It is preferable to set to about 35 to 55 Hz corresponding to the% range.

  Such a configuration expands the variable variable range to a lower range as compared with the conventional reciprocating compressor, thereby changing the range of change in the compression capability due to the load fluctuation of the cooling system in which the compressor having the above configuration is adopted. This is to increase the efficiency of the compressor at the same time. In addition, the fact that the compressor resonates in a range lower than the normal power supply frequency means that the compressor operates more efficiently in a normal low load and low speed operation state (hereinafter referred to as “general load state”). To do. Therefore, by operating the compressor at an operating frequency lower than the normal power supply frequency in a general load state, it is possible to reduce the motor iron hand and mechanical friction loss as compared with the conventional case.

  FIG. 2 is a control block diagram of a driving device in the reciprocating compressor shown in FIG. As shown in the figure, the drive unit has an inverter 51 for adjusting the voltage and frequency of the power supplied from the AC power supply 50 to the reciprocating compressor, and the input power frequency based on the information sent from the current sensor 52. And a current detection unit 53 for detecting. Further, the drive device includes a displacement detector 54 that detects the operating frequency of the piston 22 and the mover 31 based on information sent from the displacement detection sensor 42 inside the compressor, and the temperature, discharge, and suction pressure of the compressor. Or a load detection unit 55 that detects a load applied to the compressor by sensing a load of a cooling system in which the compressor is used, and an input power frequency applied to the reciprocating compressor is controlled. Therefore, the control part 56 which further controls the inverter 51 based on the information detected by the electric current detection part 53, the displacement detection part 54, the load detection part 55 grade | etc., Is further provided.

  Next, a control method for the compression operation and efficient operation control of the reciprocating compressor according to the embodiment of the present invention will be described.

  When a power source having a frequency of 60 Hz is applied from the AC power source 50 to start the compressor, the normal power source is converted by the inverter 51 into an input power source having a frequency corresponding to the resonance frequency of the compressor. That is, the frequency of the input power applied from the inverter 51 to the compressor is about 50 Hz corresponding to the resonance frequency. Therefore, the compressor performs a compression operation while the piston 22 reciprocates at an operating frequency of about 50 Hz in a general load state (low load state). That is, the compressor resonates in a frequency range lower than the frequency of the normal power supply, and the compressor can exhibit higher efficiency in the operation in the general load state where the operation ratio is high.

  Further, during the compression operation as described above, the compressor control unit 56 determines whether the load applied to the compressor is a general load or a high load based on the information sent from the load detection unit 55. In the case of a general load, the control unit 56 controls the inverter 51 so that the frequency of the input power supply corresponds to the resonance frequency of the compressor.

  Further, when the operation is performed in the general load state as described above, the control unit 56 ensures that the frequency of the input power supply always corresponds to the resonance frequency even if the resonance frequency changes due to the load fluctuation applied to the compressor. By controlling the inverter 51, the compressor can continue to maintain the resonance state and achieve the optimum efficiency of the compressor. That is, while the compressor is in operation, the mass of the operating part including the piston 22 and the mover 31 and the elasticity of the resonance spring are fixed, but the pressure of the gas applied to the piston 22 changes due to load fluctuations. Since the resonance frequency is changed, in the present invention, the input power supply frequency is changed according to the change of the resonance frequency through the control of the control unit 56, and the optimized compressor efficiency is continuously maintained.

  Such control by the control unit 56 is performed as shown in FIG. That is, the displacement detector 54 detects the operating frequency of the compressor by sensing the displacement of the piston 22 so that the frequency of the input power source follows the resonance frequency (step S61), and the current detector 53 The frequency of the input power supply is detected (step S62). Based on the information detected by the detection units 53 and 54, the control unit 56 detects a phase difference between the operating frequency and the input power supply frequency (step S63), and the detected phase difference is “0” or “ It is determined whether it is greater than 0 "(step S64, step S65). This is performed to determine the presence / absence and magnitude of the phase difference. Here, if the input power frequency matches the operating frequency, it can be said that the compressor is in a resonance state. Therefore, when the phase difference is “0”, the control unit 56 controls the inverter 51 so that the input power supply frequency is maintained as it is (step S66). On the other hand, when the phase difference is larger than “0”, the inverter 51 is controlled to increase the input power supply frequency by calculating a correction value corresponding to the phase difference (step S67), and the phase difference is “0”. Similarly, when it is smaller than "", the inverter 51 is controlled so as to decrease the input power supply frequency by calculating the correction value corresponding to the phase difference (step S68). Based on the phase difference between the input power supply frequency and the operating frequency calculated in this way, the control unit 56 controls the input power supply frequency to increase or decrease, so that the resonance frequency is changed due to load fluctuation. Even if it occurs, control is performed so that the input power supply frequency (or operating frequency) follows the resonance frequency, so that the highest compressor efficiency is exhibited.

  On the other hand, when the load detection unit 55 determines that the load applied to the compressor is higher than the general load and the compressor is in a high load state, the control unit 56 compresses the input power source frequency higher than the resonance frequency. The inverter 51 is controlled so that the capacity of the compressor is improved by being applied to the machine. That is, the reciprocating compressor according to the present invention maximizes the compressor efficiency by controlling the resonance frequency so as to coincide with the input power supply frequency in the case of a general load, and does not decrease the efficiency of the compressor in the case of a high load. In such a range, control is performed so that sufficient compression capacity can be exhibited. Such a control is often operated in a general load state rather than a normal compressor operated in a high load state, so by maximizing the efficiency in a general load state with a high operation ratio, This is intended to improve the efficiency of the compressor.

It is sectional drawing which shows the reciprocating compressor by one Embodiment of this invention. It is a control block diagram of the drive device in the reciprocating compressor shown in FIG. It is a flowchart which shows the control method of the reciprocating compressor shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Airtight container 20 Compression apparatus 30 Linear motor 42 Displacement detection sensor 50 Common power supply 51 Inverter 53 Current detection part 54 Displacement detection part 55 Load detection part 56 Control part

Claims (15)

In a reciprocating compressor having an inverter that receives a power supply, adjusts the frequency of the received power supply and inputs the power to the compressor,
The resonance frequency of the compressor is lower than the normal frequency of the received power supply;
A reciprocating compressor characterized in that a frequency of an input power source corresponds to the resonance frequency.   The reciprocating compressor according to claim 1, wherein the resonance frequency is in a range of 60 to 90% of a normal frequency of the received power supply. A control unit for controlling the operation of the compressor;
The reciprocating compression according to claim 2, wherein the control unit controls the frequency of the input power supply so that an operating frequency of the compressor follows a resonance frequency that varies depending on an operation of the compressor. Machine.   The control unit determines a phase difference between the frequency of the input power source and the operating frequency of the compressor, and controls the inverter to increase or decrease the frequency of the input power source according to a correction value corresponding to the phase difference. The reciprocating compressor according to claim 3, wherein the reciprocating compressor is controlled. A piston installed inside the compressor;
A current detector for detecting the frequency of the input power supply;
The reciprocating compressor according to claim 4, further comprising a displacement detection unit that detects a displacement of the piston and determines the operating frequency. A load detecting unit for detecting a load applied to the compressor;
When the load detected by the load detection unit is a general load, the control unit controls the inverter so that the frequency of the input power supply is equal to the resonance frequency, and the detected load is greater than the general load. The reciprocating compressor according to claim 5, wherein the inverter is controlled so that the input power source frequency is higher than the resonance frequency when the frequency is higher. An inverter for adjusting a frequency of a power source input to the compressor;
A control unit that controls the inverter so that the operating frequency of the compressor matches the frequency of the input power source based on the phase difference between the determined operating frequency and the frequency of the input power source;
The reciprocating compressor characterized by including.   The control unit controls the inverter to increase or decrease the frequency of the input power source according to a correction value corresponding to the phase difference, and the operating frequency changes according to the operation of the compressor. The reciprocating compressor according to claim 7, wherein the frequency follows the frequency. In the drive device for driving the reciprocating compressor,
An inverter that adjusts the frequency of the input power applied to the compressor;
A load detector for detecting a load applied to the compressor;
When the load detected by the load detector is a general load, the inverter is controlled so that the frequency of the input power source is equal to the resonance frequency of the compressor, and the detected load is larger than the general load. A control unit that controls the inverter so that the frequency of the input power supply is greater than the resonance frequency;
A drive device for a reciprocating compressor, comprising: A piston,
An inverter for adjusting the frequency of the input power applied to the compressor;
A current detector for detecting the frequency of the input power supply;
A displacement detector that determines the operating frequency of the compressor by detecting the displacement of the piston;
A phase difference between the input power source frequency and the operating frequency is determined so that the operating frequency follows a resonance frequency that varies depending on the operation of the compressor, and the input power source A controller that controls the inverter to increase or decrease the frequency;
A drive device for a reciprocating compressor, comprising: Determine whether the load applied to the compressor is high load or general load,
When the load applied to the compressor is a general load, a power source having the same frequency as the resonance frequency of the compressor is applied to the compressor,
A control method for a reciprocating compressor, wherein a power having a frequency larger than a resonance frequency of the reciprocating compressor is applied to the compressor when a load applied to the compressor is a high load. In a control method of a reciprocating compressor having an inverter,
Determine the phase difference between the frequency of the input power source and the operating frequency of the compressor;
A control method for a reciprocating compressor, wherein the inverter is controlled to increase or decrease the frequency of the input power supply according to a correction value corresponding to the phase difference.   The reciprocating compressor according to claim 4, wherein the control unit maintains the frequency of the input power supply when the determined phase difference is “0”.   The reciprocating compressor according to claim 5, wherein the resonance frequency varies depending on a pressure of a gas applied to the piston. Input a power supply having a frequency larger than the resonance frequency of the compressor,
Adjusting the input power supply to the resonant frequency of the compressor;
A control method for a reciprocating compressor, wherein the compressor is driven by the adjusted power source.

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