JP4265601B2 - Air conditioner - Google Patents

Description

  The present invention relates to control when a compressor of an air conditioner is stopped.

  In recent air conditioners, an increasing number of models are equipped with a DC motor 1-piston rotary compressor driven by a torque control type inverter.

  The one-piston rotary can be manufactured at low cost because of its simple structure, and there is little mechanical loss. Therefore, there is an advantage that it is possible to design a high-performance and inexpensive air conditioner by driving it with a high-performance DC motor. On the other hand, there is a demerit that the vibration is large due to the speed fluctuation of the rotor caused by the load fluctuation during one rotation of the rotor. In addition, HFC refrigerants (mainly R410A refrigerants) have become mainstream due to the need for alternative refrigerants from the viewpoint of protecting the global environment. Since the pressure is high, the speed fluctuation becomes remarkable and the vibration increases.

  As means for solving the problem of vibration, Japanese Patent Laid-Open No. 2001-37281 discloses a torque control type inverter (hereinafter referred to as torque) that suppresses speed fluctuation by finely controlling the inverter output during one rotation of the rotor of the compressor motor. A control inverter). In the torque control inverter, the rotor speed fluctuation is detected and the inverter output during one rotation of the rotor is adjusted so as to be constant. Therefore, the rotor speed is kept substantially constant and the compressor vibration is suppressed.

  This torque-controlled inverter makes it possible to greatly suppress compressor vibration during operation, but to suppress vibration during stoppage because it is caused by the rotor inertia of the compressor after the inverter power is cut off. I can't. For this reason, there has been a problem that vibration and stress at the time of stopping of the compressor itself and piping around the compressor are remarkably increased, and noise is also generated.

  In order to solve the problem of vibration at the time of stopping, it is common to absorb the vibration at the time of stopping by making the piping design around the compressor flexible shape and using a vibration isolating material such as rubber member. Method. However, the piping design has a complicated shape using long piping, and a large number of vibration-proofing materials are required, which places a burden on both the material cost and the design man-hour. Therefore, as described in Japanese Patent Laid-Open No. 2001-37281, taking advantage of the torque control inverter that can detect the rotor position of the compressor motor, the compressor speed at the time of stop and the magnitude of the phase current can be obtained. Accordingly, there are disclosed a method of interrupting the inverter energization at the rotor position effective for vibration suppression at the time of stop and a control method of further suppressing vibration at the time of stop by performing brake output at the time of stop.

  Next, problems of the disclosed control method will be described. In the torque control inverter, the output of the inverter when the torque control amount is large changes greatly according to the load change accompanying the rotation of the compressor as shown in FIG. The optimal rotor stop position for suppressing vibration during stoppage is mainly when the rotor comes near the point where the load on the compressor is lightest, that is, immediately after the refrigerant gas is discharged. Detected by output fluctuation.

  However, when the torque control amount is increased when the compressor is operated at high speed, the peak value of the compressor phase current is significantly increased and the operation efficiency is deteriorated. In order to avoid deterioration, the control amount of torque control must be set to be small during high-speed operation. However, when the torque control amount is reduced, the output of the inverter becomes difficult to reflect the fluctuation of the compressor load as shown in FIG. As a result, when stopping at high speed operation, the detection accuracy of the rotor position decreases, and the rotor position may not stop at the optimum rotor position to suppress vibration during stoppage. In that case, vibration and noise at the time of large stoppage are generated. There was a problem.

  In addition, when the compressor is stopped during high-speed operation, even if it can be stopped at an appropriate rotor position, the vibration suppression effect at the time of stopping is limited due to the magnitude of inertia of the rotor itself. The use of auxiliary members such as rubber and tape is indispensable, which has been a factor in increasing product costs. In addition, when trying to stop at an appropriate rotor position when stopping the compressor at high speed operation, the optimal rotor stop position varies greatly depending on the compressor speed and compressor load at the time of stoppage. Even in the method of stopping at the optimal rotor stop position based on the estimated load of the compressor and the load detection value due to the compressor phase current as seen in the prior art, it must be set in many cases and the control is complicated Had the problem of becoming.

  Furthermore, when the brake output is performed during high-speed / high-load operation, the current increases greatly, so that the capacity of the power element has to be increased, which also increases the product cost.

The air conditioner of the present invention is an air conditioner driven by a torque control inverter that suppresses fluctuations in the speed of the rotor of the compressor motor. When an operation stop instruction is issued, the load applied to the compressor is not less than a predetermined value. After changing the compressor speed to a compressor speed at which the control amount of torque control becomes a certain value or more with a speed change ratio that considers whether or not it is determined, compression is performed at the optimal rotor position for vibration suppression at stop The machine is stopped. With this configuration, it is possible to reliably detect the rotor position at the time of stopping, and to sufficiently exhibit the vibration suppressing effect at the time of stopping by reducing the inertia of the rotor. Further, since the inertia of the rotor is reduced, the change in the optimum rotor position due to the compressor load at the time of stop can be suppressed as much as possible, and the control can be simplified. Furthermore, since the compressor speed to be stopped can be limited, the control can be simplified.

  By using the compressor stop control according to the present invention, reliable rotor position detection can be performed, so that an air conditioner with less vibration and noise suppression at the time of stop can be provided.

  Hereinafter, the structure of the air conditioner of one embodiment of the present invention is shown in FIG. 3A. In the air conditioner, the compressor 1, the decompressor 2, the indoor heat exchanger 3, the outdoor heat exchanger 4, and the four-way valve 10 are connected by piping as shown in FIG. 3A. The compressor 1 includes a drive motor, and the drive motor has a rotor. In addition, the indoor heat exchanger 3 exchanges heat by blowing air from the indoor blower 5, and the indoor heat exchanger 3 is provided with an indoor piping sensor 7 that detects the heat exchanger temperature. Similarly, the outdoor heat exchanger 4 exchanges heat by blowing air from the outdoor blower 6, and the outdoor heat exchanger 4 is provided with an outdoor pipe sensor 8 for detecting the heat exchanger temperature. The compressor 1 is driven by an inverter 9, and the operation of the inverter 9 is controlled by a control unit 11. The control unit 11 is configured by a microcomputer, for example, and includes a speed detection unit 111 and a stop position determination unit 112 as shown in FIG. 3B, and can further include a load amount determination unit 113 or a speed change ratio variable unit 114. . FIG. 3B illustrates a case where the control unit 11 includes all the units 111, 112, 113, and 114. Among these, the means 111 and the means 112 are indispensable, but the case where the control unit 11 does not have the means 113 and 114 or only one of them is included in the present invention.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 3A and 3B.

Example 1
FIG. 4 is a diagram showing the relationship between the compressor speed and the torque control amount in the torque control inverter in the first embodiment of the present invention. In the case of the torque control setting in FIG. 4, the torque control amount is constant at Ga% from the compressor speed 0 to fb, and the control amount is gradually decreased from the compressor speed fb to fd, and the compression is greater than fd. At the machine speed, the torque control amount is set to Gc%. Here, in order to accurately determine the rotor position and stop in any operating condition in torque control, a torque control amount of Gb% or more is necessary, and the compressor speed at that time is fc.

  In such a torque control amount setting, when the compressor is operating at a high speed of fc or higher and the air conditioner operator gives an instruction to stop the operation with the remote controller, the compressor speed is changed to fc or lower. After that, it is possible to surely suppress the vibration by shutting off and stopping the inverter energization at the optimal rotor position. Note that the lower the compressor speed that is actually stopped, the greater the vibration suppression effect.Since stopping at a low speed, the change in the optimal stop position due to the load is small, so fewer control parameters are required. Is preferred. However, for example, when a stop instruction is issued from the operator during driving at the maximum speed, it takes a considerable amount of time to change to the minimum speed, so depending on the driving speed when the stop instruction is issued, The speed of stopping may be divided according to the case.

  FIG. 5 is a stop control table A in the present embodiment. When the operator's stop instruction is given during operation at a speed equal to or higher than fc shown in FIG. 4, the control unit 11 changes the rotor speed to the stop speed fc that is the upper limit of the speed at which the rotor position can be detected with high accuracy. Later, it is determined to stop at the rotor position ωc that is optimal for stopping at the speed fc. Here, the stop speed fc refers to the rotor speed at which the torque control amount of the inverter is equal to or greater than a predetermined value. On the other hand, when a stop instruction is given during operation at a speed less than fc, the controller 11 changes the rotor speed to the stop speed fa corresponding to the lowest speed at which stable operation is possible, and then at the speed fa. It is determined to stop at the rotor position ωa that is optimal for stopping. Here, the positions ωc and ωa can be set, for example, by experimentally obtaining the rotor position at which the vibration at the time of stopping becomes the smallest when stopping at a heavy load.

  FIG. 6 is a flowchart of control in the first embodiment. In step 101, when the operating air conditioner receives a stop instruction from the operator by the remote controller, the speed detector 111 detects the rotor rotation speed at the time of the stop instruction. In step 102, the stop position determining means 112 inquires the detected rotor rotation speed from the stop control table A, and determines the compressor stop speed fs and the rotor stop position ωs corresponding to fs. In the next step 103, the control unit 11 starts changing the compressor speed toward the stop speed fs. In the final step 104, when the compressor speed reaches the stop speed fs set in step 102, the inverter is deenergized at the rotor stop position ωs set in step 102, and the compressor is stopped. FIG. 7 shows a series of operations of this flowchart in time series.

(Example 2)
FIG. 8 shows the stop control table B in the second embodiment of the present invention. The stop control table B is based on the stop control table A according to the first embodiment of the present invention, and further adds the piping temperature sensor output of the condensation side heat exchanger when the compressor is stopped as a rotor stop position setting table. In the second embodiment, the control unit 11 further includes a load amount determination unit 113 in addition to the speed detection unit 111 and the stop position determination unit 112. The load amount determination unit 113 determines whether or not the load amount of the compressor is equal to or greater than a predetermined value. Based on the determination by the load amount determination unit 113, the control unit 11 can set the rotor stop position when stopping the compressor 1 to the optimum position. In the second embodiment, the load amount determination unit 113 determines the output of the pipe temperature sensor provided in the condensation side heat exchanger when the compressor 1 is stopped, so that the control unit 11 detects the rotor stop position according to the sensor output. Settings can be determined. As shown in FIG. 3A, the pipe temperature sensor output is the output of the indoor pipe temperature sensor 7 during heating, and the output of the outdoor pipe temperature sensor 8 during cooling.

  In the setting of the stop control table A described in the first embodiment, when the operator's stop instruction is performed during operation at a speed equal to or higher than fc shown in FIG. 4, the compressor is stopped after changing to the speed of fc. . The setting of the stop control table B of the second embodiment further refers to the condensation side pipe temperature Ts when stopping. That is, the load amount determination unit 113 determines whether Ts is equal to or greater than Tc or less than Tc. When Ts is equal to or greater than Tc, the control unit 11 stops the compressor at the optimum rotor stop position ωc1 corresponding to the load. When Ts is less than Tc, the control unit 11 stops the optimal rotor according to the load. The compressor can be stopped at the position ωc2.

  In the setting of the stop control table A, when the operator gives a stop instruction during operation at a speed lower than fc, the compressor is stopped after changing to the speed of fa. The setting of the stop control table B of Example 2 refers to the condensation side pipe temperature Ts when stopping. That is, the load amount determination unit 113 determines whether Ts is equal to or greater than Ta or less than Ta. When Ts is equal to or greater than Ta, the control unit 11 stops at the optimal rotor stop position ωa1 corresponding to the load. When Ts is less than Ta, the control unit 11 stops the optimal rotor stop position ωa2 corresponding to the load. It is set to stop at the position. Here, each rotor stop position ωs can be set based on experimentally obtained data.

  Thereby, even when the control for stopping is performed under various operating conditions, the vibration at the time of stopping can be more effectively suppressed. In the present embodiment, the piping temperature detected by the sensor 7 or 8 is used as means for determining the load. However, it is needless to say that the present invention is not limited to this.

(Example 3)
FIG. 9A shows the stop control table C in the third embodiment of the present invention. The stop control table C is based on the stop control table A described in the first embodiment, and further includes a compressor speed change ratio setting table.

In the third embodiment, the control unit 11 further includes a speed change ratio variable unit 114 in addition to the speed detection unit 111, the stop position determination unit 112, and the load amount determination unit 113.
The load amount determination unit 113 detects the compressor load when the stop instruction is issued, and the speed change ratio setting unit detects the compressor load when changing the compressor speed to the stop speed according to the detected compressor load. Speed change ratio can be set. The speed change ratio setting means refers to the piping temperature sensor output of the condensation side heat exchanger as the compressor load.

  When the operator's stop instruction is given during operation at a speed equal to or higher than fc shown in FIG. 4, the compressor is stopped after changing to the stop speed fc in the setting of the stop control table A described in the first embodiment. . In the setting of the stop control table C of the third embodiment, the piping temperature Tk of the condensation side heat exchanger when the stop instruction is further made is referred to. The load amount determination unit 113 determines whether Tk is equal to or greater than Tc or less than Tc. If it is less than Tc, the speed change ratio varying means 114 performs the speed change up to the stop speed at the normal compressor change speed ratio Rt. If it is equal to or greater than Tc, it is determined that the operation is heavy, and the speed change ratio variable means 114 stops at a compressor change speed ratio Rc that is slower than the normal compressor change speed ratio R. Speed change up to speed can be implemented.

  In the setting of the stop control table A, when the operator gives a stop instruction during operation at a speed lower than fc, the compressor is stopped after changing to the stop speed fa. The setting of the stop control table B of the third embodiment further refers to the condensation side piping temperature Tk when the stop instruction is issued. The load amount determination means 113 determines whether Tk is equal to or greater than Ta or less than Ta. If the Tk is less than Ta, the speed change ratio variable means 114 changes the speed up to the stop speed at the normal compressor change speed ratio Rt. carry out. If it is equal to or higher than Ta, it is determined that the operation is heavy, and the speed change ratio varying means 114 stops at a compressor change speed ratio Ra that is gentler than the normal compressor change speed ratio Rt. Change speed up to speed.

  In the stop control table C described above, after reaching the stop speed fc or fa, the rotor is stopped at the stop position ωc or ωa, respectively. On the other hand, you may control based on the stop control table D shown to FIG. 9B. In the stop control table D, after reaching the stop speed fc or fa, the control unit 11 selects the stop position in consideration of the piping temperature Tk of the condensation side heat exchanger. For example, when the stop speed is fc and the pipe temperature is equal to or higher than Tc, the stop position ωc1 is selected.

  Thereby, for example, the compressor speed can be gradually changed under heavy load, and torque control during that time can be stably performed. In the present embodiment, the pipe temperature is used as a means for determining the load.

(Example 4)
FIG. 10 is a flowchart of control in Embodiment 4 of the present invention. Since the stop control table in the present embodiment uses the same stop control table A as in the first embodiment, description thereof will be omitted. In step 401, when the operating air conditioner receives a stop instruction from the operator by the remote controller, the speed detector 111 detects the rotor rotation speed at the time of the stop instruction. In step 402, the stop position determining means 112 inquires the detected rotor rotation speed from the stop control table A, and determines the compressor stop speed fs and the rotor stop position ωs to be stopped. Next, in step 403, the change of the compressor speed is started toward the stop speed fs. In step 404, when the compressor speed reaches the stop speed fs set in step 402, the controller 11 switches the four-way valve 10 in FIG. 3A. This balances the pressure of the air conditioner. Thereafter, the inverter is deenergized at the rotor stop position ωs set in step 405, and the compressor is stopped. FIG. 11 shows a series of operations of this flowchart in time series.

  By performing the operation of switching the four-way valve 10 immediately before stopping, the load at the time of stopping the compressor can be reduced and the vibration at the time of stopping can be further reduced, and at the same time, the change in the optimum rotor position due to the load is suppressed and reduced. It is possible to perform stop control using control parameters.

(Example 5)
FIG. 12 is a flowchart of control in Embodiment 5 of the present invention. Since the stop control table in the fifth embodiment uses the same stop control table A as in the first embodiment, the description thereof is omitted. In step 501, when the operating air conditioner receives a stop instruction from the operator by the remote controller, the speed detection unit 111 detects the rotor rotation speed at the time of the stop instruction. In step 502, the stop position determining means 112 inquires the stop control table A for the detected rotor rotation speed, and determines the compressor stop speed fs and the rotor stop position ωs to stop. Next, at the same time as starting the change of the compressor speed toward the stop speed in Step 503, the control unit 11 stops the blower of the evaporation side heat exchanger. In step 504, at the same time as the compressor speed reaches the stop speed fs set in step 502, the control unit 11 stops the blower of the condensation side heat exchanger. In step 505, the inverter is deenergized at the rotor stop position ωs set in step 502, and the compressor is stopped. FIG. 13 shows a series of operations of this flowchart in time series.

  As a result, during the stop control, the air conditioner evaporator does not absorb heat, while the condenser continues to dissipate heat, reducing the load when the compressor is stopped and reducing the vibration when stopped. It is possible to suppress the change of the optimal rotor position due to, and to perform stop control even with a small number of control parameters.

(Example 6)
FIG. 14 shows a display example of the indoor unit operation lamp in the sixth embodiment of the present invention. The indoor unit operation lamp is installed in the indoor unit and is set to light up during operation. In the sixth embodiment, the control unit 11 controls the blinking operation of the operation lamp during the stop control, that is, from when the operator gives a stop instruction with the remote controller to when the compressor actually stops. For example, as shown in FIG. 14, the lighting operation for 2 seconds and the turning off for 1 second are set as one cycle, the blinking display operation is repeated, and the indoor unit operation is performed to indicate to the operator that the control operation for stopping is being performed. Control the lamp. Taking Example 5 of the present invention as an example, this blinking display operation is performed from step 501 to step 505 in the control flowchart. Of course, if this blinking display operation is required for other purposes, it goes without saying that another display operation pattern may be set.

  As a result, the person who operates the air conditioner sends a shutdown instruction with the remote controller, but the compressor is driven or the internal / external blower is moving. It is possible to prevent misunderstanding.

  As described above, according to the compressor stop control method of the present invention, reliable rotor position detection can be performed, and in any case, the compressor can be stopped at the rotor position most suitable for vibration and noise suppression during stoppage. become. In addition, by reducing the inertia of the rotor, it becomes possible to more effectively exhibit the vibration / noise suppression effect at the time of stopping. Further, since the inertia of the rotor is reduced, the change in the optimum rotor position due to the compressor load at the time of stop can be suppressed as much as possible, and the control can be simplified.

  Further, since the compressor speed to be stopped can be limited, the change of the optimum rotor position due to the compressor speed at the time of stop can be suppressed as small as possible, and the control can be simplified.

  In addition, the present invention determines the rotor stop position of the compressor motor according to the compressor load at the time of stop, so that even when stop control is performed under various operating conditions, the vibration and noise at the time of stop are more effective. Can be suppressed. For example, the compressor speed can be gradually changed during heavy load, and torque control during that time can be stably performed.

  Furthermore, according to the present invention, by changing the speed change ratio according to the compressor load at the time of stop instruction, even during stop instructions under various operating conditions, the operation during stop control can be performed stably. .

  Furthermore, according to the present invention, by switching the four-way valve 10 immediately before the compressor is stopped, the refrigerant pressure at the time of stopping can be balanced, and vibration and noise at the time of stopping can be further reduced.

  Further, while the compressor speed is changed to the speed at which the compressor speed is stopped in the stop control of the present invention, the ventilation of the condensation side heat exchanger is continued and the blower of the evaporation side heat exchanger is stopped. That is, during the stop control, the heat absorption of the evaporator of the air conditioner is not performed, and on the other hand, since the heat dissipation of the condenser is continued, an increase in load during the stop control can be suppressed. The operation can be performed stably.

  Furthermore, the present invention has a display unit for displaying that the indoor unit is in a control operation for stopping. As the display portion, a liquid crystal display device, an LED, an EL element, a light bulb, or the like can be used. After sending an operation stop instruction with the remote control by displaying that it is in operation, a user who sees that the compressor is operating and that the internal and external blowers are moving will fail the air conditioner It is possible to prevent misunderstanding that it is.

  By using the compressor stop control according to the present invention, reliable rotor position detection can be performed, so that an air conditioner with less vibration and noise suppression at the time of stop can be provided.

The figure explaining the output state of the inverter when the torque control amount is large in the torque control inverter The figure explaining the output state of the inverter when the torque control amount is small in the torque control inverter A is a configuration diagram of an air conditioner according to an embodiment of the present invention, and B is a configuration diagram of a control unit according to an embodiment of the present invention. The figure which showed the relation between the compressor speed and the torque control amount in the torque control inverter The figure which shows the stop control table A in one embodiment of this invention Flowchart of control in one embodiment of the present invention The figure which showed the series of operation | movement of the flowchart in one embodiment of this invention in time series The figure which shows the stop control table B in one embodiment of this invention A is a diagram showing a stop control table C in one embodiment of the present invention, and B is a diagram showing a stop control table D in one embodiment of the present invention. Flowchart of control in one embodiment of the present invention The figure which showed the series of operation | movement of the flowchart of control in one embodiment of this invention in time series Flowchart of control in one embodiment of the present invention The figure which showed the series of operation | movement of the flowchart of control in one embodiment of this invention in time series The figure which showed the example of a display of the indoor unit operation lamp in one embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 2 Pressure reducer 3 Indoor heat exchanger 4 Outdoor heat exchanger 5 Indoor fan 6 Outdoor fan 7 Indoor piping sensor 8 Outdoor piping sensor 9 Inverter 10 Four-way valve 11 Control part 111 Speed detection means 112 Stop position determination means 113 Load amount Determination means 114 Speed change ratio variable means

Claims (7)

An air conditioner,
A compressor,
A motor having a rotor and driving the compressor;
A torque control type inverter for driving the motor;
A control unit that controls the operation of the inverter;
Speed detecting means for detecting the rotational speed of the rotor;
Stop position determining means for determining the stop speed and stop position of the rotor based on the rotational speed, load amount determining means for determining whether or not the load applied to the compressor is a predetermined value or more,
In consideration of the determination, there is a speed change ratio variable means for reducing the speed of the rotor to the stop speed ,
Upon receipt of the stop instruction, the control unit detects the rotational speed during operation by the speed detection means, and the speed change ratio variable means decelerates to the stop speed at which the torque control amount of the inverter becomes a predetermined value or more. Thereafter, the motor is stopped at the rotor position designated by the stop position determining means. The air conditioner according to claim 1 , further comprising a temperature sensor for measuring a pipe temperature of the condensation side heat exchanger,
The load amount determination means determines the output of the temperature sensor at the time when the stop instruction is given as a load amount. 3. The air conditioner according to claim 2 , wherein the stop position determining means determines the stop position in consideration of the determination. An air conditioner,
A compressor,
A motor having a rotor and driving the compressor;
A torque control type inverter for driving the motor;
A control unit that controls the operation of the inverter;
Speed detecting means for detecting the rotational speed of the rotor;
Stop position determining means for determining a stop speed and a stop position of the rotor based on the rotation speed;
In addition, it has a four-way valve that switches between cooling and heating,
Upon receiving the stop instruction, the control unit detects the rotational speed during operation by the speed detection means, and after decelerating to the stop speed at which the torque control amount of the inverter becomes a predetermined value or more, the stop position determination means The motor is stopped at a designated rotor position, and the four-way valve is switched immediately before the compressor is stopped. 5. The air conditioner according to claim 4 , wherein the control unit determines that the rotational speed has reached the stop speed, and switches the four-way valve immediately before the compressor is stopped. An air conditioner,
A compressor,
A motor having a rotor and driving the compressor;
A torque control type inverter for driving the motor;
A control unit that controls the operation of the inverter;
Speed detecting means for detecting the rotational speed of the rotor;
Stop position determining means for determining a stop speed and a stop position of the rotor based on the rotation speed ;
A condenser side heat exchanger blower;
It has a blower for the evaporation side heat exchanger,
Upon receiving the stop instruction, the control unit detects the rotational speed during operation by the speed detection means, and after decelerating to the stop speed at which the torque control amount of the inverter becomes a predetermined value or more, the stop position determination means The motor is stopped at a specified rotor position, and at the start of deceleration to the stop speed, the blower of the evaporation side heat exchanger is stopped, and it is determined that the stop speed has been reached and the condensation side heat exchanger is reached. Stop the blower. The air conditioner according to claim 6 , further comprising an indicator,
The controller controls the lighting operation of the display during a period from when the stop instruction is received to when the motor is stopped.

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