CN112212482B

CN112212482B - Air conditioner

Info

Publication number: CN112212482B
Application number: CN202010634181.9A
Authority: CN
Inventors: 渡边雅治
Original assignee: Sharp Corp
Current assignee: Sharp Corp
Priority date: 2019-07-09
Filing date: 2020-07-02
Publication date: 2023-07-04
Anticipated expiration: 2040-07-02
Also published as: JP2021011995A; CN112212482A; JP7319115B2

Abstract

The invention provides an air conditioner which can reliably start a compressor even if the outside air temperature and the compressor temperature are high. The air conditioner starts the compressor by a first start-up procedure (S3) when the outside air temperature is equal to or less than T1 or the compressor temperature is equal to or less than T2 (NO in S1 or S2), and starts the compressor by a second start-up procedure (S4) when the outside air temperature is equal to or greater than T1 and the compressor temperature is equal to or greater than T2 (YES in both S1 and S2). The first start-up procedure is a start-up procedure with high effect of suppressing vibration and noise at the time of start-up. The second start-up procedure is a start-up procedure that can reliably start up the compressor even in an overload state.

Description

Air conditioner

Technical Field

The present invention relates to an air conditioner.

Background

Patent document 1 discloses a compressor starting program for starting a compressor in an air conditioner. Patent document 1 discloses that when a start failure at the time of starting the compressor drive motor is detected, the drive motor is restarted by sequentially increasing the start voltage by a predetermined voltage. In addition, the compressor start-up program of patent document 1 abnormally stops the air conditioner when the start-up failure reaches a predetermined number of times.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 10-267432

Disclosure of Invention

The invention aims to solve the technical problems

In general, a compressor start-up program in an air conditioner starts up a compressor while suppressing vibration and noise at the time of start-up, and in the case where the outside air temperature is high and the load of the compressor is large, reliable start-up is required.

In the compressor starting program of patent document 1, when a start failure occurs for some reason, the starting voltage of the motor is raised at the time of restarting after the start failure to improve the reliability of the start, but the start failure in the case where the load of the compressor is large is not assumed. Further, according to the study of the present inventors, a method of increasing the start-up voltage of the motor as in patent document 1 cannot be said to be an optimal method for improving the reliability of the start-up when the load of the compressor is large. Therefore, in the compressor start-up procedure in patent document 1, the compressor may not be started up even in the case where it is more severe for the start-up of the compressor.

For example, when an air conditioner operating in a state where the outside air temperature is high is temporarily stopped and restarted, that is, when both the outside air temperature and the compressor temperature are high, the compressor is in an abnormal overload state, and a protection operation is performed when the air conditioner is restarted, and the start-up of the compressor is liable to fail. In the start-up procedure of patent document 1, there is a risk that the operation of the air conditioner is stopped after repeated start-up failure, while the start-up procedure cannot cope with such a situation.

The present invention has been made in view of the above-described problems, and an object thereof is to provide an air conditioner capable of reliably starting a compressor even when both the outside air temperature and the compressor temperature are high.

Solution for solving the problem

In order to solve the above problems, an air conditioner according to the present invention includes: a judging part for judging whether the compressor is in overload state when the operation of the air conditioner is started; and a control unit that performs start control of the compressor, wherein the control unit starts the compressor by a first start program when the determination unit determines that the compressor is not in an overload state, the first start program having a high effect of suppressing vibration and noise at the start, and starts the compressor by a second start program when the determination unit determines that the compressor is in an overload state, the second start program being capable of reliably starting the compressor even in an overload state.

According to the above configuration, when it is determined that the compressor is in the overload state, the compressor is started by the second start-up program for reliably starting the compressor, so that the compressor can be reliably started while preventing the failure in starting the compressor.

In the above air conditioner, the first start-up program and the second start-up program may be configured as follows: the second start-up program is a start-up program for increasing the rotational speed of the compressor to a desired rotational speed while the motor drive current of the compressor is being forcibly increased during start-up, and the second start-up program is a program for shifting the timing of increasing the motor drive current to the first start-up program.

According to the above configuration, in the second start-up routine, the rotor of the drive motor can be accelerated in a state where the rotor of the drive motor has sufficient rotational inertia by shifting the timing of raising the motor drive current to the first start-up routine. Thus, even in an overload state where both the outside air temperature and the compressor temperature are high, the start failure of the compressor can be prevented and the reliable start can be performed.

In the above air conditioner, the first start-up program and the second start-up program may be configured as follows: and a start-up routine for increasing the motor drive current when the compressor speed reaches a predetermined compressor speed, wherein the predetermined compressor speed is set to be greater than the compressor speed of the first start-up routine in the second start-up routine.

In the above-described air conditioner, the determination unit may determine that the compressor is in an overload state when the outside air temperature is higher than the first temperature threshold and the compressor temperature is higher than the second temperature threshold.

Effects of the invention

The air conditioner of the invention has the following effects: even in an overload state where both the outside air temperature and the compressor temperature are high, the compressor can be reliably started by starting the compressor in the second start-up procedure.

Drawings

Fig. 1 is a schematic configuration diagram of an air conditioner according to a first embodiment.

Fig. 2 is a flowchart showing a compressor start-up procedure when the air conditioner according to the first embodiment starts to operate.

Fig. 3 is a timing chart showing changes in motor drive current and compressor speed in the first start-up procedure.

Fig. 4 is a timing chart showing changes in motor drive current and compressor speed in the second start-up procedure.

Detailed Description

First embodiment

Hereinafter, a first embodiment of the present invention will be described in detail with reference to the accompanying drawings. Fig. 1 is a schematic configuration diagram of an air conditioner 10 according to a first embodiment, and shows a refrigeration cycle applied to the air conditioner 10.

The air conditioner 10 is configured by an indoor unit (indoor unit) 100 and an outdoor unit (outdoor unit) 110. In the path of the refrigeration cycle (heat pump) in the air conditioner 10, the indoor heat exchanger 101 is provided on the indoor unit 100 side, and the compressor 111, the outdoor heat exchanger 112, the four-way valve 113, and the expansion valve 114 are provided on the outdoor unit 110 side. The indoor unit 100 further includes: the outdoor unit 110 sends the air heat-exchanged by the indoor heat exchanger 101 to the indoor fan 102 in the room, and includes: the air is sent to an outdoor fan 115 of the outdoor heat exchanger 112.

The air conditioner 10 further includes a first temperature sensor 121 that detects an outside air temperature and a second temperature sensor 122 that detects a compressor temperature. The first temperature sensor 121 detects the intake air temperature of the outdoor heat exchanger 112 as the outside air temperature. Further, although detailed illustration is omitted in fig. 1, the air conditioner 10 is appropriately provided with temperature sensors that detect the temperature of each part in the refrigeration cycle as needed, in addition to the first temperature sensor 121 and the second temperature sensor 122.

The four-way valve 113 switches the circulation direction of the refrigerant according to the cooling/heating operation of the air conditioner 10 (fig. 1 shows a state in the cooling operation). During the cooling operation, the refrigerant circulates in the order of the compressor 111, the four-way valve 113, the outdoor heat exchanger 112, the expansion valve 114, the indoor heat exchanger 101, the four-way valve 113, and the compressor 111. That is, during the cooling operation, the outdoor heat exchanger 112 functions as a condenser, and the indoor heat exchanger 101 functions as an evaporator. Meanwhile, during the heating operation, the refrigerant circulates in the order of the compressor 111, the four-way valve 113, the indoor heat exchanger 101, the expansion valve 114, the outdoor heat exchanger 112, the four-way valve 113, and the compressor 111. That is, during the heating operation, the indoor heat exchanger 101 functions as a condenser, and the outdoor heat exchanger 112 functions as an evaporator.

Fig. 2 is a flowchart showing a start-up procedure (compressor start-up procedure) of the compressor 111 at the start of operation of the air conditioner 10 according to the first embodiment. The following compressor starting procedure is performed by providing a control unit (not shown) provided in the air conditioner 10 to control a drive current (motor drive current) of a drive motor (not shown) of the compressor 111.

When the air conditioner 10 starts to operate, the first temperature sensor 121 detects the outside air temperature and the second temperature sensor 122 detects the compressor temperature. In the control unit, the detected outside air temperature and the detected compressor temperature are compared with a first temperature threshold T1 (for example, 50 ℃) and a second temperature threshold T2 (for example, 80 ℃) (S1, S2), respectively.

The control section (determination section) determines whether or not the compressor 111 is in an overload state at the start of operation based on the detected external air temperature and the detected compressor temperature. When at least one of the outside air temperature and the compressor temperature is equal to or lower than the threshold value, that is, when the outside air temperature is equal to or lower than T1 or the compressor temperature is equal to or lower than T2 (no in S1 or S2), it is determined that the overload state is not present and the operation proceeds to S3. When both the outside air temperature and the compressor temperature are higher than the threshold values, that is, in the case where "outside air temperature > T1" and "compressor temperature > T2" (yes in both S1 and S2), it is determined that the overload state is present and the flow proceeds to S4.

In S3, the start of the compressor 111 is started with the first start-up procedure. The 1 st startup procedure is a normal startup procedure applied when the compressor 111 is not in an overload state, and is a startup procedure with a high effect of suppressing vibration and noise at the time of startup. Fig. 3 is a timing chart showing changes in motor drive current and compressor speed in the first start-up procedure.

When the compressor 111 is started, the motor drive current is forcibly increased in the middle of the start, and the compressor rotation speed is increased to a desired rotation speed. Here, a compressor start-up procedure for eventually increasing the compressor rotation speed to N3 (for example, 3500 rpm) is exemplified. In the first embodiment, the timing of increasing the motor drive current is controlled based on the compressor rotation speed. Therefore, the control unit according to the first embodiment monitors the compressor rotation speed.

As shown in fig. 3, in the first start-up routine, the motor drive current is set to I1 at the start of start-up, and is forcibly increased to I2 at the point of time when the compressor rotation speed reaches N11 (for example, 1500 rpm) (time t 11). Further, the rise of the motor drive current is stopped at a point of time (time t 12) when the compressor rotation speed reaches N12 (for example, 2000 rpm). Then, if the compressor rotation speed reaches N3 (time t 13) and the motor drive current stabilizes at I3, the start-up of the compressor 111 is completed (the compressor start-up routine ends). Here, the motor drive current I3 is a motor drive current corresponding to the compressor rotation speed N3.

From the start to time t11, the load increases with the increase in the compressor rotation speed, and thus the current increases. From time t11 to time t12, the motor drive current I2 having a current value larger than the motor drive current I3 is forcibly applied, and the current value becomes substantially constant. When the rising period of the motor drive current ends at time t12, the motor drive current becomes (decreases) to a current corresponding to the current compressor rotation speed at that time. Then, between time t12 and time t13, the amount of work increases with an increase in the compressor speed until the compressor speed stabilizes at N3, and thus the current also increases.

In the first start-up routine, the timing of increasing the motor drive current (i.e., the compressor rotation speeds N11, N12) is set so that vibration and noise at the time of start-up can be suppressed.

In S4, the start of the compressor 111 is started with the second start-up procedure. The second startup procedure is a startup procedure applied when the compressor 111 is in an overload state and it is determined that startup failure is likely to occur in a normal startup procedure. That is, in the second start-up procedure, vibration and noise at the time of start-up become larger than those in the first start-up procedure, but the compressor 111 can be reliably started up even in an overload state. Fig. 4 is a timing chart showing changes in motor drive current and compressor speed in the second start-up procedure.

As shown in fig. 4, in the second start-up routine, the motor drive current is set to I1 at the start of the start-up, and is forcedly increased to I2 at the time point (time t 21) when the compressor rotation speed reaches N21 (for example, 2000 rpm). Further, the rise of the motor drive current is stopped at a point of time (time t 22) when the compressor rotation speed reaches N22 (for example, 2500 rpm). Then, if the compressor rotation speed reaches N3 (time t 23) and the motor drive current stabilizes at I3, the start-up of the compressor 111 is completed (the compressor start-up routine ends). In the second start-up routine, the rotation speed of the compressor, which becomes the switching timing during the rising period of the motor drive current, is set to be greater than that in the first start-up routine. That is, N21> N11, and N22> N12.

When the compressor 111 is started, the rotor of the drive motor accelerates at the timing of increasing the motor drive current, but when the compressor 111 is in an overload state, a start failure easily occurs at the acceleration timing. In the second start-up routine, since the motor drive current is increased in a state where the compressor rotation speed is higher than the first start-up routine, the timing of increasing the motor drive current is shifted after the first start-up routine. By moving the timing of raising the motor drive current backward in this way, the rotor of the drive motor is accelerated in a state where the rotor of the drive motor has sufficient rotational inertia, and failure in starting (reliable starting) of the compressor 111 can be prevented.

Second embodiment

In the first embodiment, in the first start-up routine and the second start-up routine, the timing of increasing the motor drive current is controlled based on the compressor rotation speed. However, the present invention is not limited to this, and the timing of raising the motor drive current may be controlled based on the time elapsed from the start of the start.

For example, in the timing chart shown in fig. 3, a time t11 at which the predicted compressor speed reaches N11 and a time t12 at which the predicted compressor speed reaches N12 may be set in advance, and the control unit may increase the motor drive current at a point in time when the times t11 and t12 have elapsed.

Similarly, in the timing chart shown in fig. 4, a time t21 at which the compressor rotation speed N21 is predicted to be reached and a time t22 at which the compressor rotation speed N22 is predicted to be reached are set in advance, and the control unit increases the motor drive current at the time point when the times t21 and t22 have elapsed.

In the compressor starting program according to the second embodiment, the control unit may execute the compressor starting program by measuring time with a timer instead of monitoring the compressor rotation speed.

Third embodiment

In the first embodiment described above, the current values (i.e., I1 and I2) of the motor drive current (start current) that rise stepwise during start-up are the same in both the first start-up procedure and the second start-up procedure. However, the present invention is not limited thereto, and the starting current may be different in the first starting procedure and the second starting procedure (the motor driving current I3 finally achieved is the same).

Specifically, the start-up currents I1 'and I2' in the second start-up procedure may be larger than the start-up currents I1 and I2 (I1 '> I1 and I2' > I2) in the first start-up procedure. In this way, by making the start-up current in the second start-up procedure larger than that in the first start-up procedure, a start-up failure of the compressor 111 can be prevented more reliably.

Fourth embodiment

In the first embodiment described above, the overload state in which the second start-up procedure is implemented is determined based on the external temperature and the compressor temperature. However, the present invention is not limited thereto, and the overload state in which the second start-up procedure is implemented may be determined based on other parameters.

For example, it is possible to consider that the overload state in which the second start-up procedure is implemented is determined based on the external temperature and the time elapsed since the last operation stop. That is, it is assumed that if a sufficient time has elapsed since the last operation stop, the compressor temperature is reduced to such an extent that it is not in an overload state, but if a sufficient time has not elapsed, it is expected that the temperature is maintained at a high level.

Therefore, in the compressor start-up procedure according to the fourth embodiment, when the outside air temperature is higher than the first temperature threshold T1 (for example, 50 ℃) and the time elapsed since the last operation was stopped is shorter than a predetermined time threshold (for example, 1 hour), it is considered that the compressor 111 is in an overload state, and the second start-up procedure can be executed.

The embodiments disclosed herein are merely examples in all aspects and are not to be construed as limiting. Accordingly, the technical scope of the present invention is not to be interpreted by the above-described embodiments only, but is to be defined according to the description of the claims. The technical scope of the present invention includes all changes that come within the meaning and range of equivalency of the claims.

Description of the reference numerals

10 air conditioner, 100 indoor units (indoor units), 101 indoor heat exchanger, 102 indoor fan, 110 outdoor unit (outdoor unit), 111 compressor, 112 outdoor heat exchanger, 113 four-way valve, 114 expansion valve, 115 outdoor fan, 121 first temperature sensor, 122 second temperature sensor

Claims

1. An air conditioner, comprising:

a judging unit that judges whether or not the compressor is in an overload state at the start of the operation of the air conditioner; and

a control unit for controlling the start of the compressor,

when the judgment unit judges that the compressor is not in an overload state, the control unit starts the compressor by a first start-up program having a high effect of suppressing vibration and noise at the time of starting,

in the case where the judgment section judges that the compressor is in an overload state, the control section causes the compressor to start up with a second start-up program that can reliably start up the compressor even in the overload state,

the first start-up procedure and the second start-up procedure are: a start program for increasing the rotational speed of the compressor to a desired rotational speed while forcibly increasing the motor drive current of the compressor during start-up,

in the second start-up routine, the timing to raise the motor drive current is shifted to after the first start-up routine.

2. An air conditioner according to claim 1, wherein,

the first start-up procedure and the second start-up procedure are: a start program for increasing the motor drive current when the compressor rotation speed reaches a predetermined compressor rotation speed,

in the second start-up procedure, the predetermined compressor speed is set to be greater than the compressor speed of the first start-up procedure.

3. An air conditioner according to claim 1 or 2, wherein,

the determination unit determines that the compressor is in an overload state when the outside air temperature is higher than a first temperature threshold and the compressor temperature is higher than a second temperature threshold.