阅读说明：本技术 控制装置、压缩机、电动压缩机、传送带驱动型压缩机、车辆用空调装置及控制方法 (Control device, compressor, electric compressor, conveyor belt-driven compressor, air conditioning device for vehicle, and control method ) 是由 藤田胜博 山本隆英 鹈饲徹三 于 2019-01-18 设计创作，主要内容包括：本发明提供一种无误启动地进行压缩机的保护控制的控制装置。控制装置根据设置于制冷剂回路的低压侧的压力传感器所检测出的压力值和所述压力值的经时变化来启动所述制冷剂回路所具备的压缩机的保护控制。(The invention provides a control device for protecting and controlling a compressor without false start. The control device starts protection control of a compressor provided in a refrigerant circuit on the basis of a pressure value detected by a pressure sensor provided on a low-pressure side of the refrigerant circuit and a temporal change in the pressure value.)

1. A control device is provided with:

and a protection control unit that starts protection control of a compressor provided in the refrigerant circuit based on a pressure value detected by a pressure sensor provided on a low-pressure side of the refrigerant circuit and a temporal change in the pressure value.

2. The control device according to claim 1,

the protection control unit starts the protection control when the pressure value is in a negative pressure state within a predetermined range for a predetermined time or longer.

3. The control device according to claim 1 or 2,

the protection control unit starts the protection control when the pressure value decreases by a predetermined value or more within a predetermined time in a state of a negative pressure.

4. The control device according to claim 1 or 2,

the protection control unit starts the protection control when the pressure value does not change for a predetermined time or more during operation of the compressor.

5. The control device according to any one of claims 1 to 4,

the protection control unit cancels the protection control according to a predetermined recovery condition corresponding to a condition when the protection control is activated.

6. The control device according to any one of claims 1 to 5,

The protection control unit further includes: and a notification unit configured to notify that the protection control cannot be cancelled, if it is determined that the protection control cannot be cancelled.

7. The control device according to any one of claims 1 to 6,

the protection control unit controls the start of the protection control based on a value obtained by averaging the pressure values.

8. An air conditioning device for a vehicle, comprising:

a compressor; and

the control device of any one of claims 1 to 7, which controls the compressor.

9. A compressor for use in the vehicular air conditioning device according to claim 8,

the compressor is integrally provided with a pressure sensor constituting the control device.

10. A compressor is provided with:

a compression mechanism;

the control device of any one of claims 1 to 7; and

and a pressure sensor disposed on a low pressure side.

11. An electric compressor integrally includes:

a motor;

a compression mechanism driven by the motor;

the control device of any one of claims 1 to 7, which controls the motor; and

a pressure sensor disposed at a low pressure side,

the protection control portion starts the protection control by reducing a rotation speed of the motor or stopping the motor.

12. A conveyor belt-driven compressor integrally comprising:

a compression mechanism driven by power transmitted from a drive source;

the control device according to any one of claims 1 to 7, which controls a clutch mechanism that transmits power of the drive source; and

a pressure sensor disposed at a low pressure side,

the protection control unit switches the on state of the clutch mechanism to the off state to start the protection control.

13. An air conditioning device for a vehicle, comprising the compressor according to any one of claims 10 to 12.

14. A control method for starting protection control of a compressor provided in a refrigerant circuit on the basis of a pressure value detected by a pressure sensor provided on the low-pressure side of the refrigerant circuit and a change over time in the pressure value.

Technical Field

The present invention relates to a control device, a compressor, an electric compressor, a conveyor belt-driven compressor, a vehicle air conditioner, and a control method.

The present application claims priority from japanese patent application No. 2018-62063, filed in japan on 28/3/2018, and the contents thereof are incorporated herein by reference.

Background

The following techniques are proposed: a pressure sensor is provided on the suction side of a compressor of an air conditioning apparatus for a vehicle, and protection control of the compressor is started using the detected pressure value (patent document 1). Patent document 1 describes the following: when the pressure value is detected to be negative, protection control is performed to reduce the rotation speed of the compressor. Patent document 2 discloses an air conditioning device for a vehicle, which controls the rotation speed of a compressor so as not to lower the suction refrigerant temperature or the suction refrigerant pressure of the compressor more than a target value.

Prior art documents

Patent document

Patent document 1: japanese patent laid-open publication No. 2010-13017

Patent document 2: international publication No. 2017/002546

Disclosure of Invention

Technical problem to be solved by the invention

However, in the case of the air conditioner for a vehicle, the pressure on the suction side may become a negative pressure even if the compressor is normally operated depending on various conditions during the traveling of the vehicle. If the protection control is started only based on the pressure value or temperature on the suction side of the compressor, the protection control may be erroneously started.

The present invention provides a control device, a compressor, an electric compressor, a belt-driven compressor, a vehicle air conditioner, and a control method that can solve the above problems.

Means for solving the technical problem

According to one aspect of the present invention, a control device includes: and a protection control unit that starts protection control of a compressor provided in the refrigerant circuit based on a pressure value detected by a pressure sensor provided on a low-pressure side of the refrigerant circuit and a temporal change in the pressure value.

According to an aspect of the present invention, the protection control unit starts the protection control when the pressure value is in a negative pressure state within a predetermined range for a predetermined time or longer.

According to an aspect of the present invention, the protection control unit starts the protection control when the pressure value decreases by a predetermined value or more within a predetermined time in a state of a negative pressure.

According to an aspect of the present invention, the protection control unit starts the protection control when the pressure value does not vary for a predetermined time or more during operation of the compressor.

According to an aspect of the present invention, the protection control unit cancels the protection control according to a predetermined recovery condition corresponding to a condition when the protection control is activated.

According to an aspect of the present invention, the protection control unit further includes: and a notification unit configured to notify that the protection control cannot be cancelled, if it is determined that the protection control cannot be cancelled.

According to an aspect of the present invention, the protection control unit controls the start of the protection control based on a value obtained by averaging the pressure values.

According to an aspect of the present invention, there is provided an air conditioning device for a vehicle, including: a compressor; and the control device described in any one of the above, which controls the compressor.

According to an aspect of the present invention, the compressor is used in the vehicle air conditioner, and the compressor integrally includes a pressure sensor constituting the control device.

According to an aspect of the present invention, there is provided a compressor including: a compression mechanism; the control device of any of the above; and a pressure sensor disposed on the low pressure side.

According to an aspect of the present invention, there is provided an electric compressor integrally including: a motor; a compression mechanism driven by the motor; the control device of any one of the above, which controls the motor; and a pressure sensor provided on a low-pressure side, wherein the protection control unit starts the protection control by reducing a rotation speed of the motor or stopping the motor.

According to an aspect of the present invention, there is provided a conveyor belt-driven compressor integrally including: a compression mechanism driven by power transmitted from a drive source; the control device according to any one of the above, which controls a clutch mechanism that transmits power of a drive source; and a pressure sensor provided on a low-pressure side, wherein the protection control unit switches an on state of the clutch mechanism to an off state to start the protection control.

According to an aspect of the present invention, there is provided an air conditioning device for a vehicle, including the compressor described in any one of the above.

According to an aspect of the present invention, there is provided a control method for starting protection control of a compressor provided in a refrigerant circuit, based on a pressure value detected by a pressure sensor provided on a low-pressure side of the refrigerant circuit and a temporal change in the pressure value.

Effects of the invention

According to the control device, the compressor, the electric compressor, the conveyor belt-driven compressor, the vehicle air conditioner, and the control method, the protection control for preventing the failure of the compressor can be started without false start under appropriate conditions.

Drawings

Fig. 1 is a diagram showing an example of an air conditioning apparatus including an electric compressor according to a first embodiment of the present invention.

Fig. 2 is a flowchart showing an example of protection control in the first embodiment of the present invention.

Fig. 3 is a diagram showing an example of an air conditioner including a conveyor belt-driven compressor according to a second embodiment of the present invention.

Fig. 4 is a view 1 showing an example of a control circuit according to a second embodiment of the present invention.

Fig. 5 is a view 2 showing an example of a control circuit according to a second embodiment of the present invention.

Detailed Description

< first embodiment >

Hereinafter, protection control of the compressor according to the first embodiment of the present invention will be described with reference to fig. 1 to 2.

Fig. 1 is a diagram showing an example of an air conditioning apparatus including an electric compressor according to a first embodiment of the present invention. The air conditioner 1 shown in fig. 1 is, for example, an air conditioner for a vehicle. The air conditioner 1 includes an electric compressor 10, a condenser 11, a receiver 12, an expansion valve 13, and an evaporator 14.

The air conditioner 1 is used for cooling/heating in a vehicle. The electric compressor 10 compresses a refrigerant, and supplies the high-pressure refrigerant to the condenser 11. The refrigerant is condensed by radiating heat in the condenser 11. The condensed/liquefied refrigerant flows into the receiver 12. The refrigerant separates into a vapor phase and a liquid phase in the receiver 12. The liquid-phase refrigerant flows out of the receiver 12 and is decompressed by the expansion valve 13. The low-pressure refrigerant having passed through the expansion valve 13 is supplied to the evaporator 14. The refrigerant absorbs heat and is gasified by heat exchange with the outside air in the evaporator 14. The vaporized refrigerant is sucked into the electric compressor 10. The electric compressor 10 compresses and discharges a low-pressure refrigerant. The electric compressor 10, the condenser 11, the receiver 12, the expansion valve 13, the evaporator 14, and pipes through which the refrigerant connected thereto passes form a refrigerant circuit. The refrigerant is repeatedly circulated through the refrigerant circuit to perform the cooling operation or the heating operation in the vehicle.

The controller 20 controls the rotation speed of the electric compressor 10 based on a command value from an ECU (electronic control unit), not shown, mounted on the vehicle, and controls the cooling operation or the heating operation so that the temperature in the vehicle becomes a desired temperature. The motor-driven compressor 10 has a compression function portion 50 and a power supply chamber portion 51 partitioned within a casing 106. The electric compressor 10 includes a pressure sensor 101, a compression mechanism 102, and a motor 103 in the compression function portion 50. The electric compressor 10 includes a power supply unit 104 having an Inverter (INV)105 in a power supply chamber portion 51, and a control device 20 for controlling the inverter 105. The electric compressor 10 is, for example, a scroll compressor.

The pressure sensor 101 is inserted into a housing 106 constituting the compression function portion 50.

The compression function portion 50 becomes an airtight space (airtight portion) for sealing the refrigerant, and for example, an insertion port of the pressure sensor 101 is sealed with a sealing material or the like. The pressure sensor 101 is provided, for example, in the vicinity of the suction side of the compression mechanism 102, and measures the pressure of the refrigerant before compression (hereinafter, referred to as a low-pressure value). The pressure sensor 101 is connected to the control device 20 in the housing 106 constituting the power supply chamber portion 51, and outputs a measured low pressure value to the control device 20.

The compression mechanism 102 includes a swirling scroll, a fixed scroll, and a compression chamber formed by these. The motor 103 rotationally drives the compression mechanism 102. The compression mechanism 102 and the motor 103 are coupled by a crankshaft. When the motor 103 rotates, the orbiting scroll rotates about the crankshaft, and the refrigerant in the compression chamber is compressed. The compression mechanism 102 discharges the compressed refrigerant.

The power supply unit 104 receives dc power from a battery mounted in the vehicle. The inverter 105 converts the dc power into a three-phase ac power and supplies the ac power to the motor 103. The inverter 105 controls the current output to the motor 103 in accordance with an instruction from the control device 20. The control device 20 controls the inverter 105 based on a rotation speed command value of the motor 103 instructed from the ECU, and controls the motor 103 to operate at the instructed rotation speed. The electric compressor 10 is an inverter-integrated electric compressor incorporating a pressure sensor 101 and a controller 20.

When the cooling operation or the heating operation is continued, the evaporator is cooled and frost formation (frosting) may occur. In general, in a state where the frost formation occurs, the opening degree of the expansion valve 13 is controlled to be small, and the circulation amount of the refrigerant is reduced. Then, the refrigerant pressure on the suction side of the electric compressor 10 decreases, and depending on the degree of the decrease, the refrigerant pressure may cause a failure of the electric compressor 10. In addition, the pressure on the suction side of the compressor may decrease for various reasons. Conventionally, when a pressure value on a suction side (low pressure) of a compressor becomes equal to or lower than a threshold value or a pressure value on a discharge side (high pressure) becomes equal to or higher than a threshold value, protection control for stopping the compressor or decelerating the rotation speed is performed. In the present embodiment, a pressure sensor is provided at a low pressure portion in the refrigerant space in the electric compressor 10 to monitor a low pressure value of the refrigerant. The control device 20 determines whether or not to start the protection control of the electric compressor 10 based on the change in the low-pressure value or the change with time.

The control device 20 is a computer such as a microcomputer including a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). As shown in the figure, the control device 20 includes a sensor information acquisition unit 21, a protection control unit 22, a notification unit 23, a storage unit 24, and a timer 25. As described above, the control device 20 has the following functions: the cooling/heating operation or the heating operation of the air conditioner 1 is performed by controlling the opening degree of the inverter 105 or the expansion valve 13 based on a command value from an ECU (not shown) of the vehicle. Hereinafter, descriptions other than the protection control of the electric compressor 10 will be omitted.

The sensor information acquisition unit 21 acquires the low pressure value detected by the pressure sensor 101.

The protection control unit 22 starts protection control of the electric compressor 10 in accordance with the low pressure value and the temporal change in the low pressure value. For example, when the low pressure value is kept at a negative pressure (a pressure lower than atmospheric pressure) for a predetermined time or longer, the protection control unit 22 starts protection control. For example, the protection control unit 22 starts the protection control when the low pressure value is a negative pressure and the low pressure value decreases at a predetermined rate of decrease or more. For example, the protection control unit 22 starts protection control when the low pressure value does not change for a predetermined time or more. After the protection control is started, the protection control unit 22 releases the protection control when a predetermined recovery condition is satisfied.

The notification unit 23 notifies the user of the activation state of the protection control and the like. For example, the notification unit 23 notifies the user of activation and deactivation of the protection control, failure to deactivate the protection control, and the like.

The storage unit 24 stores various information. For example, the storage unit 24 stores the low pressure value and the like acquired by the sensor information acquisition unit 21.

The timer 25 measures time.

Next, the protection control of the first embodiment will be described on the premise of the configuration of fig. 1.

Fig. 2 is a flowchart showing an example of protection control in an embodiment of the present invention.

First, the control device 20 starts the operation of the electric compressor 10 by an instruction operation to start air conditioning by a user. Then, the pressure sensor 101 starts measuring a low pressure value. For example, the pressure sensor 101 measures a low pressure value at regular time intervals. The sensor information acquisition unit 21 starts acquisition of the low pressure value from the pressure sensor 101 (step S11). The sensor information acquisition unit 21 thereafter also acquires the low pressure value at predetermined time intervals. The control device 20 starts measuring time using the timer 25 (step S12). The timer 25 measures time. The sensor information acquisition unit 21 associates the acquired low pressure value with the acquisition time of the low pressure value measured by the timer 25, and records the associated value in the storage unit 24.

Next, the protection control unit 22 determines the start condition of the protection control using the low pressure value recorded in the storage unit 24 from the predetermined time ago to the latest low pressure value (step S13). At this time, the protection control unit 22 reads the low pressure value measured in a predetermined period from the storage unit 24, calculates an average value for each time of rotation of the scroll, and determines the following start condition based on a temporal change in the calculated average value. The refrigerant pressure pulsates due to the rotation of the scroll, and the average value is calculated in order to eliminate the influence of the pulsation in accordance with the determination of the start-up condition.

(condition 1) the state in which the low pressure value is a negative pressure within a predetermined range continues for a predetermined time.

For example, when the low pressure value is maintained at-0.03 MPaG or less for 30 seconds or longer, the protection control unit 22 determines that the protection control is to be activated. When the low pressure value is maintained at-0.03 MPaG or less for 30 seconds or longer, the evaporator 14 is likely to freeze. When the evaporator 14 freezes, the expansion valve 13 is closed, and the refrigerant gas cannot flow into the electric compressor 10 or the inflow amount of the refrigerant gas decreases. Accordingly, it becomes difficult to supply the refrigerant or the lubricating oil to the electric compressor 10. If the electric compressor 10 continues to operate in this state, there is a possibility that the electric compressor 10 may be damaged by biting. Therefore, when the above-described "condition 1" is satisfied, the protection control unit 22 determines that the protection control of the electric compressor 10 is performed.

Conventionally, there is a control in which a pressure sensor is provided in a pipe on the suction side of a compressor, and when the pressure detected by the pressure sensor becomes negative pressure, protection control is started. However, in the case of this control, even in a state where the evaporator is not frozen, the negative pressure may be temporarily detected, and in this case, the protection control may be unnecessarily executed. A temperature sensor is provided near the evaporator, and there is control for inferring icing of the evaporator from the temperature detected by the temperature sensor and initiating protection control. The temperature sensor is generally provided in the vicinity of a portion of the evaporator where the temperature is most greatly reduced, and when 0 ℃ or more, for example, 2 ℃ is sensed in order to prevent freezing of the evaporator, the freezing of the evaporator is prevented by activating the protection control. However, for example, when the temperature sensor is not properly positioned, or when the temperature distribution of the evaporator changes depending on the operating conditions and the temperature of a portion other than the vicinity of the installation portion of the temperature sensor is reduced to the maximum, or the like, or when the evaporator freezes and the freezing progresses to the vicinity of the temperature sensor, there is a possibility that the cold air from the evaporator does not reach the temperature sensor and the temperature higher than the actual evaporator temperature is measured. Then, the protection control is not started, the evaporator is frozen, and the compressor may malfunction. In the electric compressor 10 of the present embodiment, the pressure sensor 101 inserted into the compression mechanism 102 directly detects the pressure of the low-pressure portion of the refrigerant, and therefore, the negative pressure of the low-pressure value can be reliably detected, and the protection control can be started after confirming that the state continues for a certain time. This can prevent the false activation of the protection control which may occur in the conventional technique. The low pressure value of "condition 1" can be set in the range of-0.03 to-0.04 MPaG depending on the operating conditions. The duration of condition 1 can be set within a range of 5 to 30 seconds.

(condition 2) the low-pressure value is depressurized in a negative pressure state for a predetermined time by a predetermined value or more.

For example, when the low pressure value is reduced from 0MPaG to-0.05 MPaG within 5 seconds, the protection control unit 22 determines that the protection control is started. When the low-pressure value becomes a negative pressure and then rapidly decreases, there is a high possibility that foreign matter such as clogging of the expansion valve 13 with fine foreign matter enters a certain portion in the refrigerant circuit and the refrigerant circuit is closed. If the electric compressor 10 is operated in this state, a failure may occur. Therefore, the protection control unit 22 determines whether or not to start the protection control based on the above "condition 2". This makes it possible to protect the electric compressor 10 with high accuracy.

When a shut valve is provided in the refrigerant circuit, the shut valve must be opened and then started when the electric compressor 10 is started. Even if the electric compressor 10 erroneously activates the shut valve in the shut state for some reason, the protection control of the electric compressor 10 can be promptly started based on the "condition 2" to prevent damage. The time condition of "condition 2" can be set within a range of 5 to 10 seconds.

(condition 3) the low pressure value does not vary for a predetermined time during the operation of the electric compressor 10.

When a state in which the low pressure value is not changed is observed while the electric compressor 10 is operated, the protection control is started. For example, when the pressure of the electric compressor 10 is not changed from the pressure before the start even when the compressor is operated, a failure of the compressor can be expected. In this case, the compressor stop is implemented. Conventionally, a non-contact sensor of a vortex type or the like is provided in a compressor, and a lock sensor for detecting locking of the compressor by sensing that a component inside the compressor is not operated by using the sensor is provided. In the present embodiment, the pressure sensor 101 detects this. When the electric compressor 10 is locked for some reason, the compression mechanism 102 no longer sucks the refrigerant gas. If the refrigerant gas is no longer sucked, the low pressure value detected by the pressure sensor 101 does not change. According to the protection control of the present embodiment, the lock of the compressor can be detected by the determination of "condition 3" without providing a lock sensor.

The protection control unit 22 determines the above-described "condition 1" to "condition 3" with reference to the time series data of the low pressure values recorded in the storage unit 24. When any of the conditions "condition 1" to "condition 3" is not satisfied (step S14; no), the protection control unit 22 repeats the determination of step S13. The motor-driven compressor 10 continues to operate normally.

When any one of the "condition 1" to the "condition 3" is satisfied (step S14; yes), the protection control unit 22 starts protection control (step S15). The protection control means stopping the electric compressor 10 or reducing the rotation speed of the electric compressor 10. The protection control unit 22 may instruct the inverter 105 to decelerate or stop the motor 103 in accordance with the satisfied condition. For example, when "condition 1" is satisfied, the protection control unit 22 instructs the inverter 105 to drive the motor 103 at a predetermined low rotation speed. By rotating at a low speed, a decrease in the low pressure value can be prevented. For example, when "condition 2" or "condition 3" is established, the protection control unit 22 instructs the inverter 105 to stop the motor 103. By stopping the electric compressor 10, the compressor can be prevented from being damaged. The protection control unit 22 records the start time of the protection control in the storage unit 24.

When the protection control is started, the protection control unit 22 then determines a recovery condition for releasing the protection control and recovering the motor-driven compressor 10 to the normal operation state (step S16). For example, the protection control unit 22 determines whether or not to cancel the protection control based on the recovery condition corresponding to the condition when it is determined in step S14 that the protection control is started. For example, when the protection control is determined to be activated based on "condition 1", the protection control unit 22 determines that the recovery condition is satisfied when a predetermined set time has elapsed from the activation start time of the protection control. The time required for the ice to subside is set, for example, in the range of 5 seconds to 120 seconds. For example, when it is determined that the protection control is started based on "condition 2" or "condition 3", the protection control section 22 determines that the operation is stopped permanently (not automatically returned to the normal operation). This is because the electric compressor 10 cannot be operated unless the cause of the foreign matter mixing into the refrigerant circuit or the compressor lock is eliminated. In order to confirm "condition 2" or "condition 3", protection control unit 22 may start electric compressor 10 at a rotation speed with a low possibility of breakage, and determine whether or not "condition 2" or "condition 3" is satisfied. For example, the protection control unit 22 may determine that the vehicle is stopped permanently (the protection control cannot be released) when "condition 2" or "condition 3" is satisfied 3 consecutive times, and restart the normal operation in this state if the condition is not satisfied due to restart.

When the return condition is satisfied (step S17; satisfied), the protection control unit 22 cancels the protection control (step S18) and resumes the normal operation. This corresponds to the case where a predetermined set time (5 to 120 seconds) has elapsed after the start of the protection control by the "condition 1" or the case where the "condition 2" or the "condition 3" is not reproduced for confirmation at the time of restart after the start of the protection control by the "condition 2" or the "condition 3" in the above example. When the normal operation is resumed, the control device 20 performs control to rotate the motor 103 at a rotation speed based on the ECU command value, for example. While the control device 20 is executing the normal operation, the protection control portion 22 continues to monitor the low pressure value and makes the determination of step S13.

When the return condition is not satisfied (step S17; not satisfied), the protection control unit 22 waits until the determination of step S16 is satisfied. This corresponds to the period until the predetermined set time (5 seconds to 120 seconds) elapses after the start of the protection control by the "condition 1" in the above example.

When the recovery is not possible (step S17; recovery is not possible), the notification unit 23 notifies the user of the abnormality of the electric compressor 10 and the failure to start the electric compressor 10 (step S19). For example, a notification from the notification portion 23 may be received, and an abnormality of the electric compressor 10 or a message prompting to check the electric compressor 10 or a lamp may be displayed on a display device of the driver's seat by the ECU. This corresponds to the case where "condition 2" or "condition 3" is satisfied or the case where the phenomenon of "condition 2" or "condition 3" is satisfied even if the restart for confirmation is performed in the above example.

As described above, the electric compressor 10 of the present embodiment integrally includes the pressure sensor 101 for detecting the pressure on the low-pressure side, the compressor main body (the compression mechanism 102, the motor 103), and the control device 20. Since the control device 20 is provided, the electric compressor 10 can autonomously start the protection control.

Since the pressure sensor 101 is provided in the compressor air-tight section, control can be performed based on an accurate refrigerant pressure, and erroneous determination can be suppressed, as compared with a case where protection control is started based on a measurement value of a pressure sensor provided in the suction-side pipe outside the compressor or a temperature sensor provided in the vicinity of the evaporator. Since the control is performed based on the average value of the measurement values of the pressure sensors 101, the influence of the pulsation of the pressure value generated by the scroll can be reduced.

Similarly to the pressure sensor 101, a pressure sensor may be provided on the high-pressure side of the electric compressor 10 so as to be able to directly detect the pressure of the refrigerant, and for example, when the pressure on the high-pressure side becomes equal to or higher than a threshold value, the protection control may be started.

According to the present embodiment, the protection control is started not only by a change in the low pressure value to the negative pressure but also by a change over time in the low pressure value to the negative pressure. Therefore, it is possible to suppress the erroneous start of the protection control while preventing the malfunction of the electric compressor 10, and to realize the operation of the electric compressor 10 and the operation of the air conditioner 1 with high efficiency.

< second embodiment >

In the first embodiment, the protection control is described taking the electric compressor 10 as an example. In many cases, a belt-driven compressor that obtains a driving force of the compressor from an engine of a vehicle is used in the air conditioner for a vehicle. In the second embodiment, a conveyor belt-driven compressor 10a will be described. The same components as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

Fig. 3 is a diagram showing an example of an air conditioner including a conveyor belt-driven compressor according to a second embodiment of the present invention. The air conditioner 1a shown in fig. 3 includes a conveyor-driven compressor 10a, a condenser 11, a receiver 12, an expansion valve 13, and an evaporator 14. The conveyor belt-driven compressor 10a includes a pressure sensor 101, a compression mechanism 102, a magnetic clutch 107, a pulley portion 108, and a control device 20a for controlling the magnetic clutch 107. Of these, at least the pressure sensor 101 and the compression mechanism 102 are housed in the casing 106, and the pressure sensor is provided in a region where the refrigerant becomes low pressure during operation. The control portion 20a is provided on the outer surface of the low-pressure side housing. The conveyor belt-driven compressor 10a is, for example, a scroll compressor. The rotary shaft of the compression mechanism 102 is coupled to the magnetic clutch 107. The pulley portion 108 is connected to the engine 40 of the vehicle via the belt 41. The compression mechanism 102 and the pulley 108 can be coupled to and decoupled from each other by a magnetic clutch 107.

When the controller 20a turns on the magnetic clutch 107, the magnetic clutch 107 and the pulley 108 are engaged. When the magnetic clutch 107 is in the on state, the rotation of the engine 40 is transmitted by the belt 41, and the pulley portion 108, the magnetic clutch 107, and the rotation shaft of the compression mechanism 102 rotate. Thereby, in the compression mechanism 102, the orbiting scroll rotates, and the refrigerant is compressed. That is, the conveyor belt-driven compressor 10a is in an operating state.

When the control device 20a turns off the magnetic clutch 107, the magnetic clutch 107 and the pulley 108 are disengaged. When the magnetic clutch 107 is in the off state, the pulley portion 108 idles due to the rotation of the engine 40. At this time, the conveyor belt-driven compressor 10a is in a stopped state.

The control device 20a controls transmission of power supplied from the engine 40 to the compression mechanism 102 by switching the magnetic clutch 107 between an on state and an off state in accordance with a command value from an ECU (electronic control unit), not shown. The engine 40 transmits power to the compression mechanism 102 to operate the compression mechanism 102, thereby performing cooling operation or heating operation so that the interior of the vehicle is at a desired temperature. When air conditioning is not necessary, the control device 20a sets the magnetic clutch 107 to the off state. The pressure sensor 101 is inserted into an airtight portion on the low pressure side of the compression mechanism 102, and measures a low pressure value. As in the first embodiment, the pressure sensor 101 is connected to the control device 20a and outputs a measured low pressure value to the control device 20 a. The conveyor belt-driven compressor 10a is an integrated conveyor belt-driven compressor incorporating a pressure sensor 101 and a controller 20 a.

The control device 20a includes a sensor information acquisition unit 21, a protection control unit 22a, a notification unit 23, a storage unit 24, and a timer 25. The functions of the sensor information acquisition unit 21, the notification unit 23, the storage unit 24, and the timer 25 are the same as those of the first embodiment.

The protection control section 22a starts protection control of the conveyor belt-driven compressor 10a in accordance with the low pressure value and the temporal change in the low pressure value. For example, the protection control unit 22a determines the start of the protection control based on "condition 1" to "condition 3" described in fig. 2. When the protection control is started, the protection control unit 22a disconnects the magnetic clutch 107 to separate the conveyor belt-driven compressor 10a from the engine 40. The protection control unit 22a performs protection control by stopping the conveyor belt driven compressor 10a in this manner. After the protection control is started, the protection control unit 22a releases the protection control when a predetermined recovery condition is satisfied. When the protection control is released, the protection control unit 22a connects the conveyor belt-driven compressor 10a and the engine 40 via the conveyor belt 41 by turning the magnetic clutch 107 on. As in the first embodiment, the protection control unit 22a may perform control based on a value obtained by averaging the measurement values of the pressure sensor 101 in units of the rotation cycle of the orbiting scroll, or the like. Fig. 4 and 5 show a control circuit of the clutch mechanism including the control device 20a, the magnetic clutch 107, and the pulley portion 108.

Fig. 4 is a view 1 showing an example of a control circuit according to a second embodiment of the present invention.

As shown in fig. 4, the battery provided in the vehicle is connected to the control device 20a, the pressure sensor 101, and the switching element 120 via the relay 30. The relay 30 is provided outside the conveyor belt-driven compressor 10 a. The switching element 120 is provided inside the conveyor belt-driven compressor 10 a. The relay 30 includes a relay switch 31 and a relay coil 32. When the ECU causes a current to flow to the relay coil 32, the relay switch 31 is turned on, and the power is supplied to the control device 20a, the pressure sensor 101, and the switching element 120. For example, the switching element 120 is formed of an IGBT (insulated gate bipolar transistor). The magnetic clutch 107 is connected to a battery of the vehicle via a switching element 120. That is, when the relay 30 is in the on state and the switching element 120 is in the on state, the magnetic clutch 107 and the pulley portion 108 are tightened, and the rotation of the engine 40 can be transmitted to the compression mechanism 102.

The on state and the off state of the switching element 120 are controlled by the control device 20 a. That is, the control device 20a receives a command signal from the ECU to operate the conveyor belt-driven compressor 10a, and when the protection control portion 22a does not activate the protection control, the control device 20a controls the switching element 120 to the on state in accordance with an instruction from the ECU. Then, the magnetic clutch 107 is energized and tightened to the pulley portion 108. Thereby, the compression mechanism 102 rotates to compress the refrigerant. On the other hand, when the protection control unit 22a starts the protection control, the control device 20a controls the switching element 120 to be in the off state. Then, the magnetic clutch 107 is disengaged from the pulley portion 108, and the conveyor belt-driven compressor 10a is set to the non-operating state. This can suppress the negative pressure operation of the conveyor belt-driven compressor 10a, and avoid a failure, a breakage, or the like.

Fig. 5 is a view 2 showing an example of a control circuit according to a second embodiment of the present invention.

As shown in fig. 5, a battery provided in the vehicle is connected to the control device 20a, the pressure sensor 101, and the switching element 121 via the relay 30. The battery and the magnetic clutch 107 are connected via the switching element 121 and the relay 30. The relay 30 is provided outside the conveyor belt-driven compressor 10 a. The switching element 121 is provided inside the conveyor belt-driven compressor 10 a. The relay 30 includes a relay switch 31 and a relay coil 32. For example, the switching element 121 is formed of a MOS-FET which is less expensive than the IGBT illustrated in fig. 4. When the switching element 121 is turned on, a current flows to the relay coil 32, and the relay switch 31 is turned on. When the relay switch 31 is turned on, the battery supplies current to the control device 20a, the pressure sensor 101, and the magnetic clutch 107. In this state, the magnetic clutch 107 is in an on state, and the magnetic clutch 107 and the pulley portion 108 are tightened, so that the rotation of the engine 40 can be transmitted to the compression mechanism 102.

The on state and the off state of the switching element 121 are controlled by the control device 20 a. That is, the control device 20a receives a command signal from the ECU to operate the conveyor belt-driven compressor 10a, and when the protection control portion 22a does not activate the protection control, the control device 20a controls the switching element 121 to the on state in accordance with an instruction from the ECU. Then, the relay 30 is turned on, and electric power is supplied from the battery to the magnetic clutch 107 to be fastened to the pulley portion 108. Thereby, the compression mechanism 102 rotates to compress the refrigerant. On the other hand, when the protection control unit 22a starts the protection control, the control device 20a controls the switching element 121 to be in the off state. Then, the magnetic clutch 107 is disengaged from the pulley portion 108, and the conveyor belt-driven compressor 10a is set to the non-operating state. This can suppress the negative pressure operation of the conveyor belt-driven compressor 10a, and avoid a failure, a breakage, or the like.

Conventionally, a general configuration is such that a battery and a magnetic clutch 107 are connected via a relay 30, and the on state and the off state of the magnetic clutch 107 are switched by energization of a relay coil 32 by an ECU. In the conveyor belt-driven compressor 10a, as illustrated in fig. 4 and 5, a switching element may be provided between the magnetic clutch 107 and the relay 30, and the on state and the off state of the switching element may be switched by the determination of the protection control unit 22 a. Such a control circuit can be mounted by relatively easy wiring processing and the like.

The determination of the start and recovery of the protection control by the protection control unit 22a is the same as the processing described in fig. 2 of the first embodiment.

The scroll compressor has a large capacity (discharge amount) at the time of high rotation as compared with other types of compressors, and is often used in an air conditioner for a vehicle. When a conveyor belt-driven scroll compressor is used, the rotational speed rapidly increases at the time of rapid acceleration of the vehicle or the like, and the operation is performed in a high speed region. In the operation in the high speed region (at the time of high rotation), since the discharge amount is increased, a large amount of refrigerant is sucked, and even in a state where the evaporator is not frozen, the low pressure value may become a low pressure of a negative pressure or less in a short time. If a conventional control is performed on a scroll compressor such that a protection control is activated when the pressure on the suction side of the compressor becomes negative, there is a problem that the compressor is frequently stopped or decelerated even in such a case.

The belt-driven compressor is operated by driving the engine, and connection and disconnection with the engine are often controlled by the ECU. Since the protection control cannot be actively started on the compressor side, there is a possibility that the compressor is damaged due to a failure such as failure to start the compressor in a situation where the protection control should be started.

According to the present embodiment, since the belt-driven compressor 10a is configured to integrally include the pressure sensor 101, the compression mechanism 102, the clutch mechanism (the magnetic clutch 107, the pulley portion 108) that connects the compression mechanism 102 and the drive source (the engine 40), and the control device 20a that controls the clutch mechanism, the belt-driven compressor 10a can autonomously start the protection control and can prevent the occurrence of a failure in advance.

According to the present embodiment, the protection control is started in accordance with the temporal change in the low pressure value that becomes the negative pressure. Therefore, even if the negative pressure is temporarily measured at the time of rapid acceleration of the vehicle or the like, the protection control is not erroneously started. According to the present embodiment, since the low-pressure protection control of the compressor against the freezing of the evaporator, the clogging of the refrigerant circuit, and the like can be performed without erroneous operation and the determination of the locked state of the compressor 10a can be performed, a special lock detection device is not required.

Since the pressure sensor 101 is provided in the airtight portion, whether or not the protection control can be started can be determined based on the accurate refrigerant pressure. The conveyor belt-driven compressor 10a also exhibits the same effects as the electric compressor 10 of the first embodiment. A pressure sensor may be provided on the high-pressure side of the belt-driven electric compressor 10a so as to be able to directly detect the pressure of the refrigerant, and the protection control may be started when the pressure on the high-pressure side becomes equal to or higher than a threshold value, for example.

Further, since the control device 20a including the switching element is directly provided on the outer surface of the low-pressure side casing 106 of the compressor 10a, heat generation of the element can be cooled, and reliability can be improved.

All or a part of the functions of the control devices 20 and 20a may be realized by hardware such as an LSI (Large scale Integrated Circuit), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), an FPGA (Field-Programmable Gate Array), an Integrated Circuit, or the like. All or a part of the functions of the control devices 20 and 20a may be constituted by a computer provided with a processor such as a CPU. In this case, the process of each process in the control devices 20 and 20a can be realized by executing a program by a CPU or the like included in the control device 20, for example. The program executed by the control device 20, 20a may be recorded in a computer-readable recording medium, and may be realized by reading out and executing the program recorded in the recording medium.

In the first and second embodiments, the example in which the protection operation is autonomously performed without passing through the ECU of the vehicle is disclosed, but the information of the pressure sensor 101 or the control devices 20 and 20a may be directly notified to the ECU and be collectively controlled.

Further, the components of the above embodiments may be replaced with known components as appropriate without departing from the scope of the present invention. The technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

Industrial applicability

According to the control device, the compressor, the electric compressor, the conveyor belt-driven compressor, the vehicle air conditioner, and the control method, the protection control for preventing the failure of the compressor can be started without false start under appropriate conditions.

Description of the symbols

1. 1 a-air conditioning device, 10-electric compressor, 10 a-belt-driven compressor, 11-condenser, 12-receiver, 13-expansion valve, 14-evaporator, 20 a-control device, 21-sensor information acquisition section, 22 a-protection control section, 23-notification section, 24-storage section, 25-timer, 30-relay, 31-relay switch, 32-relay coil, 40-engine, 41-belt, 101-pressure sensor, 102-compression mechanism, 103-motor, 105-inverter, 104-power supply unit, 106-housing, 107-magnetic clutch, 108-pulley section, 120, 121-switching element.