JP2009024929A - Compressor control device, refrigerating air conditioning device and rotary compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compressor control device for suppressing vibration in stopping an operation of a compressor. <P>SOLUTION: This control device of the compressor comprising a compressor main body 1 having periodical torque pulsation in accompany with rotation, a motor 2 for driving the compressor main body, and a supporting member 4 for supporting the compressor main body and the motor, further comprises an invertor 8 for variable-speed driving the motor, and a control means 9 for controlling the motor through the invertor, and the control means 9 has a shut-down control means 10 for changing an output frequency of the invertor so that a rotational frequency of the compressor becomes near a mechanical resonance frequency determined by inertia of the compressor and the motor, a spring constant of the supporting member and a damping constant, when the stop of the compressor is required, and then turns off the output of the invertor. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a control device for a compressor having torque pulsation, and more particularly to a control device for stopping operation of a compressor.

  As a technique related to control at the time of operation stop of a conventional compressor, for example, there is one disclosed in Patent Document 1. This is because, in an air conditioner equipped with a compressor driven by an electric motor, an electromagnetic contactor is provided in an electric circuit that supplies electric power from the power source to the electric motor, and the electromagnetic contactor is opened and closed to change from the power source to the electric motor. If the controller detects that the compressor is in operation after performing control with the compressor stopped, the electromagnetic contactor is abnormally welded. It is determined that there is a control, and the control accompanied by the operation of the compressor is performed by canceling the control accompanied by the stop of the compressor. In other words, when the welding abnormality of the magnetic contactor is found, it is intended to protect the compressor by continuing the operation of the compressor that cannot be stopped without providing a fuse or the like. The compressor is then stopped by manually turning off the power breaker.

JP 2006-189244 A (Claim 1, FIG. 1, FIG. 2)

However, mechanical vibrations occur when the compressor is stopped. Since the compressor is connected to a metal refrigerant pipe for sucking and discharging refrigerant, the vibration of the compressor may cause metal fatigue in the pipe and cause it to tear, reducing the reliability of the equipment. It was a factor.
In addition, the vibration of the compressor may cause noise. In particular, since single rotary compressors and reciprocating compressors with large load torque pulsations are used in refrigerators and home air conditioners, etc., these devices are installed close to the living space. There is a high demand for low vibration and low noise.

In view of the above problems, an object of the present invention is to obtain a compressor control device that suppresses vibrations when a compressor is stopped.
Another object of the present invention is to obtain a refrigeration air conditioner and a rotary compressor to which the compressor control device is applied.

  A compressor control device according to the present invention includes a compressor body having periodic torque pulsation as it rotates, a motor that drives the compressor body, and a support member that supports the compressor body and the motor. The compressor control device includes an inverter that drives the motor at a variable speed, and a control unit that controls the motor via the inverter, and the control unit has a stop request for the compressor. After changing the output frequency of the inverter so that the rotation frequency of the compressor is close to the mechanical resonance frequency determined by the inertia of the compressor and the motor, the spring constant and the damping constant of the support member, A shutdown control means for turning off the output is provided.

  Since the shutdown control means of the present invention is configured as described above, there is an effect of suppressing vibration when the compressor is stopped and suppressing metal fatigue of the refrigerant piping.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram of a compressor and a compressor control device according to Embodiment 1 of the present invention.
As shown in FIG. 1, a compressor main body 1 including, for example, a hermetic rotary compressor includes a compressor shell 3 that is a hermetic container, and a motor 2 that drives the compressor main body 1 is attached to the compressor shell 3. Built in. The compressor body 1 and the motor 2 are supported by a support member 4. The fluid (refrigerant) to be compressed is introduced into the compressor body 1 through the suction pipe 5 and compressed, and flows out to the discharge pipe 6. The motor 2 is driven by an inverter 8 connected to a DC power source (for example, a DC power source obtained by converting AC power into DC power) 7. The control means 9 generates a control signal for the current or voltage output from the inverter 8. The control means 9 generates a drive signal for the inverter 8 so as to control the rotation speed and operation / stop of the motor 2. The control means 9 has a shutdown control means 10, and the shutdown control means 10 executes an operation sequence until the compressor is stopped when a request for stopping the compressor is generated in the control means 9. Here, the control means 9 is composed of, for example, a microcomputer, and the shutdown control means 10 is composed of S / W (software) of the microcomputer.

  When the above-described compressor is used, for example, when applied to a refrigeration cycle apparatus, the configuration is as shown in FIG. In FIG. 2, 130 is a compressor, 131 is a four-way valve, 132 is an outdoor heat exchanger that functions as a condenser, 133 is an indoor heat exchanger that functions as an evaporator, 134 is an expansion valve, 135 is refrigerant piping, 136 is A bypass valve provided in a bypass pipe 137 connected to the discharge pipe and the suction pipe, 138 is an outdoor fan, and 139 is an indoor fan.

  Here, mechanical vibration of the compressor configured as described above will be described with reference to FIG. FIG. 3 is a model diagram for analyzing the mechanical vibration of the compressor. Each element of the compressor is mechanically composed of a rotating part (mainly including a compressor rotor, a motor rotor, a shaft, etc.), a compressor shell (in addition to the shell, a compressor cylinder, a motor stator). Including a member fixed to an equal shell) and a support member. Here, the inertia of the rotating part is Jr, the inertia of the compressor shell is Jsh, the spring constant of the support member is ksh, the damping constant is Dsh, the deflection angle of the compressor shell is θ, the output torque of the motor is Tm, Assuming that the load torque is Tl, the equation of motion related to the vibration of the compressor shell is the second-order ordinary differential equation expressed by Equation 1.

Here, when Dsh ² <4 · Jsh · ksh, the shell displacement due to the torque difference Tl−Tm (hereinafter referred to as ΔT) is damped vibration. The natural frequency ωres [rad / s] of the damped vibration, the natural frequency (natural frequency) fres [Hz], and the deflection angle θ of the compressor shell are expressed by the following equations (2), (3), and (4). expressed. In Expression (4), C ₁ , C ₂ , and C ₃ are constants determined by Jsh, Dsh, and ksh.

   In order to prevent noise diffusion due to compressor vibration in refrigerators and air conditioner outdoor units, the natural frequency is selected to be 30 Hz or less, and the compressor operating frequency is generally higher than this frequency (40 rps or more). It is driven by.

  In order to suppress the deflection angle θ (circumferential vibration) of the compressor shell from the equation (4), it is necessary to reduce the torque difference ΔT between the load torque Tl of the rolling mill and the output torque Tm of the motor. First, the load torque of the compressor will be described with reference to FIG. FIG. 4 is a diagram showing the relationship between the crank angle of the rotary compressor and the load torque. Since the rotary compressor has a mechanism for sequentially sucking, compressing, and discharging fluid, the load torque varies greatly depending on the rotational position of the rotor (also called a rolling piston). This load torque depends on the pressure on the discharge side, and the pressure on the discharge side depends on the number of rotations of the compressor. Therefore, when operating at a low speed, the load torque becomes small.

  Next, the relationship between the change in the output torque of the motor and the torque difference will be described with reference to FIG. FIG. 5 is a diagram showing a change in torque before and after the motor operation is stopped. In order to drive a compressor having a load torque as shown in FIG. 4 with low vibration, the motor output torque may be operated so as to substantially match the load torque. That is, the motor output torque shown in FIG. 5 may be generated as a waveform having a crank angle of 0 to 720 deg and controlled so that the torque difference becomes substantially zero. However, when the operation of the compressor is stopped, the power supply from the inverter becomes zero, so the motor output torque becomes almost zero, the torque difference becomes equal to the load torque of the compressor, and the torque difference increases rapidly. That is, the vibration after the inverter stops depends on the behavior of the load torque of the compressor. In practice, it is difficult to completely match the compressor load torque and the motor output torque even during operation, and some excitation force remains. For this reason, the frequency (resonance frequency shown by the equation (2)) at which this excitation force is likely to vibrate is designed to some extent away from the operating range. Since the outdoor unit of the refrigerator or the air conditioner has an operation prohibition band of about 0.1 to 10 rps, the lower limit value fmin of the operation frequency is resonance frequency + operation prohibition band / 2. That is, the lower limit value fmin of the operating frequency is set so as to satisfy the following formula (5).

Next, generation of the vibration of the compressor shell due to the sudden change of the torque difference in FIG. 5 will be described with reference to FIGS. 6 and 7 show the time transition of the swing angle (circumferential vibration) of the compressor shell when the inverter is stopped. FIG. 6 shows the low speed operation and FIG. 7 shows the high speed operation.
The circumferential vibration of the compressor occurs at the same time as the output stop of the inverter. However, during high-speed rotation, as shown in FIG. 7, the amplitude of the load torque becomes large and ΔT in equation (4) becomes large. The angle (circumferential vibration) becomes large.

  From the above, next, the operation of the shutdown control means in Embodiment 1 of the present invention will be described based on FIG. FIG. 8 is a diagram showing a change in operation frequency (inverter output rotation speed) when the compressor is stopped in the first embodiment. When it becomes necessary to stop the compressor during operation, first the inverter operating frequency is reduced toward the natural frequency of equation (2). Next, when the operating frequency approaches the operating frequency lower limit value fmin shown by the equation (5), the drive signal from the inverter is stopped and the motor output is turned off.

  By controlling as described above, it is possible to suppress the load torque that is a factor of the compressor shell vibration when the inverter is stopped, and the shell vibration due to the sudden torque change at the time of stop is suppressed. FIG. 9 is a diagram showing the relationship between the operating frequency at which the inverter is stopped and the vibration of the compressor. The minimum value of the compressor vibration tends to become smaller as the speed becomes lower in the vicinity of the mechanical resonance frequency fres (within twice the fres). There is. Therefore, the upper limit fmax of the operating frequency is set so as to satisfy the following formula (6).

Embodiment 2. FIG.
A second embodiment that exhibits the effects of the present invention will be described. The configuration of the compressor and the compressor control device is the same as that in FIG. 1 and the description thereof is the same as that in the first embodiment, so that the description thereof will be omitted.

FIG. 10 is a diagram showing the vibration characteristics of the compressor shell when the rotation phase (crank angle) of the compressor when the inverter is stopped is changed. There are three operating frequencies at the time of stop, 15 rps, 20 rps, and 25 rps.
As shown in FIG. 10, when the crank angle when the inverter is stopped is about 300 to 60 degrees, the vibration of the compressor shell is large. According to FIG. 4, the crank angle of 300 to 60 deg is a region where the load torque pulsation during one rotation is negative and tends to decrease, and the compressor partially accelerates immediately after the inverter stops, resulting in increased vibration. That is, the stop timing of the compressor is performed while avoiding the phase that becomes the acceleration region, that is, by setting the crank angle to 60 to 300 deg, it is possible to further reduce the vibration at the time of stop.

Next, the operation will be described based on the flowchart of FIG. First, the compressor is started and operated (steps 1 and 2). Here, the control means 9 confirms the operation end command, and if it is a situation to end the operation, instructs the shutdown control means 10 to execute a sequence for stopping the compressor (step 3). The shutdown control means 10 that has received the instruction to terminate the operation first changes the output rotational speed of the inverter 8 to the rotational speed for ending energization. Since the method of giving this frequency is the same as in the first embodiment, the description thereof is omitted (steps 4 and 5). Next, the shutdown control means 10 determines whether or not the rotation phase (crank angle) of the compressor is a phase (60 to 300 deg) at which the vibration at the time of stop described above is reduced, and if so, The energization to the inverter 8 is stopped, and the output torque of the motor 2 is turned off (step 7).
By controlling as described above, the shell vibration of the compressor when the inverter is stopped can be suppressed.

Embodiment 3 FIG.
Next, a third embodiment that exhibits the effects of the present invention will be described with reference to FIG. FIG. 12 is a configuration diagram showing a schematic cross section of the rotary compressor according to the third embodiment of the present invention.
In the rotary compressor 130, the rotor 112 performs an eccentric rotational movement in the cylinder 111. The rotor 112 is eccentrically attached to the shaft 113 and is rotationally driven by a motor (not shown). A vane 114 whose tip abuts on the rotor 112 is slidably provided on the cylinder 111. The vane 114 moves in a predetermined direction (in this example, the vertical direction) as the rotor 112 rotates, and the cylinder 111 The inner space is separated into a suction chamber 115 on the suction side and a compression chamber 116 on the discharge side. The position of the vane 114 is controlled by the actuator 117. The fluid to be compressed is sucked into the suction chamber 115 through the suction port 118, and the fluid compressed in the compression chamber 116 by the rotation of the rotor 112 is discharged from the discharge valve 119. When the actuator 117 is energized, the vane 114 is moved to a position away from the rotor 112, and the differential pressure between the suction side pressure and the discharge side pressure is made zero.

  Next, the operation will be described with reference to FIG. During normal operation of the compressor, the actuator 117 is turned off to perform the compression operation. That is, the rotor 112 performs eccentric rotational movement in the order of FIGS. 13A to 13B, whereby fluid suction, compression, and discharge are repeatedly performed. When the compressor 1 is stopped from such a compressor operating state, the actuator 117 is turned on. Then, as shown in FIGS. 13D to 13F, the vane 114 is pulled up to the open position, whereby the suction chamber 115 and the compression chamber 116 communicate with each other to be in an unloaded state. Therefore, the compressor load torque is almost zero. Thereafter, the motor, which is the driving force of the compressor 130, is turned off. Before and after this energization, there is almost no torque difference, so vibration during stoppage is suppressed.

Embodiment 4 FIG.
Next, a fourth embodiment that exhibits the effects of the present invention will be described with reference to FIG. FIG. 14 shows the configuration of the refrigeration cycle apparatus according to Embodiment 4 of the present invention. In this refrigeration cycle apparatus, similarly to FIG. 2, the compressor 130, the outdoor heat exchanger 132, the expansion valve 134, the indoor heat exchanger 133, and the four-way valve 131 are connected by a refrigerant pipe 135 to constitute a refrigeration cycle. . The discharge side and the suction side of the compressor 1 are connected by a bypass pipe 137 having a bypass valve 116. In the figure, 138 is an outdoor fan, 139 is an indoor fan, 161 is a power source, and 162 is a switch for turning on / off the power supplied to a motor (not shown) of the compressor 1.

  Next, the operation will be described. When a stop request is generated during the operation of the compressor 1, first, the bypass valve 136 is opened by a control means (not shown), and the pressure difference between the suction side pressure and the discharge side pressure of the compressor 1 is made zero. Thereby, the load torque and its pulsation of the compressor 1 become extremely small. Thereafter, the switch 162 is changed from closed (ON) to open (OFF), and the operation of the compressor 1 is stopped. As described above, the torque fluctuation accompanying the stop is suppressed, and the motor stops with low vibration.

Embodiment 5 FIG.
In addition, although Embodiment 4 demonstrated by the method of providing a bypass valve, if there is no time restriction, you may substitute by expansion valve control, without using a bypass valve. The configuration diagram in this case is as shown in FIG. The operation is as shown in FIG. When a request to stop the compressor 1 is generated, the opening degree of the expansion valve 134 is increased, and the pressure difference between the suction side pressure and the discharge side pressure of the compressor 1 is gradually reduced. Then, after a predetermined time has elapsed, the compressor 1 is stopped. The above operation makes it possible to stop the compressor with low vibration.

The present invention is not limited to the embodiment described above. For example, as an application example of the present invention, low vibration and low noise of an inverter compressor for refrigeration and air conditioning can be mentioned. A single rotary type or reciprocating type compressor having a large load torque pulsation is used in refrigerators and home air conditioners. Since these devices are installed close to the living space, there is a high demand for low vibration and low noise of the devices.
Moreover, since this invention reduces the stress concerning refrigerant | coolant piping, it has the effect of prevention of pipe tearing by metal fatigue, and can suppress aged deterioration of refrigeration air-conditioning equipment.

The block diagram of the compressor and compressor control apparatus in Embodiment 1 of this invention. The block diagram of a refrigerating-cycle apparatus. The model figure for analyzing the mechanical vibration of a compressor. The figure which shows the relationship between the crank angle of a rotary compressor, and load torque. The figure which shows the change of the torque before and behind a motor driving | operation stop. The figure which shows the vibration of a compressor shell at the time of stopping an inverter during low speed driving | operation. The figure which shows the vibration of the compressor shell at the time of stopping an inverter during high speed operation. The figure which shows the change of the operating frequency at the time of the compressor stop in Embodiment 1. FIG. The figure which shows the relationship between the driving frequency which stops an inverter, and the vibration of a compressor. The figure which shows the characteristic of the vibration of a compressor shell at the time of changing the rotation phase (crank angle) of the compressor at the time of stopping an inverter. FIG. 9 is an operation explanatory diagram of the second embodiment. The block diagram of the compressor in Embodiment 3 of this invention. FIG. 9 is an operation explanatory diagram of the third embodiment. The block diagram of the refrigerating-cycle apparatus in Embodiment 4 of this invention. The block diagram of the refrigerating-cycle apparatus in Embodiment 5 of this invention. FIG. 10 is an operation explanatory diagram of the fifth embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Compressor body, 2 motor, 3 compressor shell, 4 support member, 5 suction piping, 6 discharge piping, 7 DC power supply, 8 inverter, 9 control means, 10 shutdown control means, 111 cylinder, 112 rotor, 113 shaft, 114 Vane, 115 Suction chamber, 116 Compression chamber, 117 Actuator, 118 Suction port, 119 Discharge valve, 130 Compressor, 131 Four-way valve, 132 Outdoor heat exchanger, 133 Indoor heat exchanger, 134 Expansion valve, 135 Refrigerant piping, 136 bypass valve, 137 bypass pipe, 138 outdoor fan, 139 indoor fan, 161 power supply, 162 switch.

Claims (10)

In a compressor control device comprising a compressor main body having periodic torque pulsation with rotation, a motor for driving the compressor main body, and a support member for supporting the compressor main body and the motor.
An inverter that drives the motor at a variable speed; and a control unit that controls the motor via the inverter;
When there is a request to stop the compressor, the control means has a rotational frequency of the compressor in the vicinity of a mechanical resonance frequency determined by the inertia of the compressor and the motor, a spring constant and a damping constant of the support member. Thus, after changing the output frequency of the inverter, it has a shutdown control means for turning off the output of the inverter. In a compressor control device comprising a compressor main body having periodic torque pulsation with rotation, a motor for driving the compressor main body, and a support member for supporting the compressor main body and the motor.
An inverter that drives the motor at a variable speed; and a control unit that controls the motor via the inverter;
The control means has a shutdown control means for turning off the output of the inverter after shifting the rotational phase of the compressor to a predetermined phase where the vibration of the compressor is lowered when the compressor is requested to stop. A compressor control device characterized by that. In a compressor control device comprising a compressor main body having periodic torque pulsation with rotation, a motor for driving the compressor main body, and a support member for supporting the compressor main body and the motor.
An inverter that drives the motor at a variable speed; and a control unit that controls the motor via the inverter;
When there is a request to stop the compressor, the control means has a predetermined rotation speed range in which the rotation frequency of the compressor is determined by the inertia of the compressor and the motor, the spring constant and the damping constant of the support member. The output frequency of the inverter is changed as described above, and the shutdown control means for turning off the output of the inverter after the rotational phase of the compressor is shifted to a predetermined phase where the vibration of the compressor is reduced is provided. Compressor control device. The lower limit value fmin [rps] of the predetermined rotational speed range satisfies the following expression when Jsh is the inertia of the compressor and the motor, ksh is the spring constant of the support member, and Dsh is the damping constant. The compressor control device according to claim 1 or 3.

The upper limit value fmax [rps] of the predetermined rotational speed range satisfies the following expression when Jsh is the inertia of the compressor and the motor, ksh is the spring constant of the support member, and Dsh is the damping constant. The compressor control device according to claim 1 or 3.

  4. The compressor control device according to claim 2, wherein the predetermined phase exists within a range of 60 to 300 deg in coordinates with the rotation direction being positive from the top dead center of the compressor. 5. In a compressor control device comprising a compressor main body having periodic torque pulsation with rotation, a motor for driving the compressor main body, and a support member for supporting the compressor main body and the motor.
A switch for turning on / off electric power supplied to the motor, bypass means for operating the suction side pressure and discharge side pressure of the compressor to be balanced, and control means for controlling operation and stop of the compressor; With
When stopping the compressor from operating, the control means first operates the bypass means to reduce the pressure difference between the suction side pressure and the discharge side pressure of the compressor, and then turns off the switch. A compressor control device characterized by that. A compressor having periodic torque pulsation with rotation; a motor that drives the compressor; and a support member that supports the compressor and the motor, the compressor, an indoor heat exchanger, an expansion mechanism, In a refrigerating and air-conditioning apparatus that connects outdoor heat exchangers with refrigerant pipes and performs outdoor and outdoor heat transfer using an indoor blower,
When the compressor is stopped during operation, the expansion mechanism is relaxed, and the compressor is stopped after reducing the pressure difference between the suction side pressure and the discharge side pressure of the compressor. apparatus. A compressor having periodic torque pulsation as it rotates, a motor for driving the compressor, a support member for supporting the compressor and the motor, and a switch for turning on / off the input power to the motor; In the refrigerating and air-conditioning apparatus comprising bypass means that operates to balance the pressure in the cylinder of the compressor, and control means that controls operation and stop of the compressor,
When stopping the compressor from operating, the control means first operates the bypass means to reduce the pressure difference between the suction side pressure and the discharge side pressure of the compressor, and then turns off the switch. A refrigeration air conditioner characterized by that. A cylinder, a rotor that performs eccentric rotational movement in the cylinder, a motor that drives the rotor, a suction port that sucks a fluid to be compressed into the cylinder, and a discharge valve that discharges the compressed fluid from the cylinder A rotary compressor comprising: a vane that separates a space in the cylinder into a suction chamber on the suction side and a compression chamber on the discharge side with a tip abutting against the rotor; and an actuator that drives the vane.
When the compressor is stopped during operation, the rotary compressor is configured to control the vane to an open position by the actuator to unload the compression chamber, and then stop energizing the motor.

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