JPH0840053A - Protecting method of motor-driven compressor and device having it - Google Patents

Abstract

PURPOSE:To prevent overheat or breakdown by arranging setting of a temperature sensor of a motor coil in three stages of a high temperature, a further high temperature and a low temperature, restricting rotating speed of a compressor when it exceeds first setting, and stopping the compressor when it exceeds second setting or becomes smaller than third setting. CONSTITUTION:When a coil temperature becomes 120 deg.C or higher and lower than 130 deg.C, first of all, rotating speed is restricted (S101 and 102) without stopping a compressor. The rotating speed is restricted as it is until the coil temperature becomes lower than 100 deg.C, and when it becomes lower than 100 deg.C, the rotating speed is restored (S103 to 105). If a motor is locked or an outdoor fan runs into trouble, since the coil temperature happens to exceeds 130 deg.c, when disconnection of a thermistor is detected in operation, the compressor is stopped (S106 and 107). As protection against a low temperature condition, when the coil temperature becomes lower than (-)20 deg.C, the compressor is stopped, and separate auxiliary heating is actuated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for protecting an electric compressor, and is particularly useful for an electric inverter type air conditioner mounted on an automobile.

[0002]

2. Description of the Related Art A conventional automobile air conditioning compressor receives power from an engine via a belt to compress a refrigerant. Further, since the conventional vehicle heats by using hot water for cooling the engine as a heat source, the compressor is dedicated to the cooling operation.

To protect the compressor, as shown in FIG. 2, the surface temperature of the compressor 11 is controlled by the bimetal SW1.
When one inspection is performed at 2, and when it detects a predetermined high temperature state, the clutch 13 of the compressor is turned off, and the compressor 11
Was to stop. In the conventional automobile compressor, since the belt 14 drives the compressor even if the pressure difference between the discharge pressure and the suction pressure remains when the compressor is once stopped, it can be immediately restarted. .

An electric compressor is used as a room air conditioner for home use. As shown in FIG. 3, the electric compressor 5 is also protected by the bimetal SW 12 for detecting the compressor surface temperature and internal temperature. Then, when it detects a predetermined high temperature state, the electric compressor 15 is stopped.

If the differential pressure between the discharge pressure and the suction pressure remains when the electric compressor temporarily stops, the starting torque of the motor increases and an excessive current is applied to the inverter driving the electric compressor. Since it flows, it cannot be started immediately after the compressor is stopped, and it started after waiting for a while (about 1 to 3 minutes). In the case of the room air conditioner, since the space to be air-conditioned is large, the waiting time has a relatively small effect on the room temperature.

[0006]

However, when an electric inverter type air conditioner used for a conventional room air conditioner is installed in, for example, an electric vehicle which has been developed in recent years, the following problems occur.

First, in the case of an automobile, the operating environment becomes more severe than that of the electric compressor for the current room air conditioner, and the compressor often overheats even in the normal use range, and in that case, it had to be stopped. And when it stops,
As mentioned above, it started after waiting for a while (about 1 to 3 minutes), but in the case of a car air conditioner, the space to be air-conditioned is small, the influence of solar radiation, etc. Since the occupant is made comfortable by applying to the occupant, there is a problem that the waiting time described above has a large influence on the room temperature and the comfort of the occupant, and the room temperature and the blowout temperature fluctuate greatly, which makes the occupant uncomfortable. It was This is remarkable in comparison with the fact that the belt-driven compressor of the current automobile can be immediately restarted.

Secondly, the heat source for heating in an electric vehicle is
Since the amount of heat generated from the driving motor is extremely small compared to the current engine, it is unavoidable to rely on the heat pump heating, and in this case, the compressor has an extremely low outside temperature as compared with the room air conditioner. Since it is operated, there is a problem that the suction refrigerant is likely to be in a liquid state and causes liquid compression, or causes a defective lubrication function to destroy the compressor.

The present invention solves the above problems and prevents the passenger from becoming uncomfortable due to a large change in the room temperature and the blowout temperature due to overheating of the compressor, and at the same time reliably and accurately operates the electric compressor from a high temperature state. The purpose is to protect and prevent the compressor from being broken due to liquid compression or poor lubrication function when the compressor is operated to a very low outside temperature by heat pump heating.

[0010]

In order to solve the above-mentioned problems, a method for protecting an electric compressor according to the present invention and an apparatus having the same are provided as follows: (1) Compress a refrigerant for air conditioning to wind a motor and its winding A first setting for detecting a high temperature state of the winding by a protection method when an electric compressor having a built-in temperature sensor for detecting a line temperature is controlled by an inverter at a variable rotation speed, and the first setting There is a second setting for detecting a higher temperature state than the setting, and a third setting for detecting a low temperature state of the winding, and when the winding temperature exceeds the first setting, the electric compressor The rotation speed is limited, and the electric compressor is stopped when the winding temperature exceeds the second setting or becomes lower than the third setting.

(2) A protection method for controlling an electric compressor, which compresses an air-conditioning refrigerant and incorporates a motor and a temperature sensor for detecting the winding temperature of the motor, at a variable speed with an inverter. A first setting for detecting a high temperature state of the winding, and a second setting for detecting a higher temperature state than the first setting, and when the winding temperature exceeds the first setting. The rotation speed of the electric compressor is limited, and the electric compressor is stopped when the winding temperature exceeds the second setting.

(3) A protection method for controlling an electric compressor, which compresses an air-conditioning refrigerant and has a motor and a temperature sensor for detecting a winding temperature of the motor, at a variable speed with an inverter. A first setting for detecting a high temperature state of the winding, a second setting for detecting a higher temperature state than the first setting, and a fourth setting for detecting a disconnection state of the temperature sensor. However, when the winding temperature exceeds the first setting, the rotational speed of the electric compressor is limited, and the winding temperature exceeds the second setting, or the fourth setting of the temperature sensor When a disconnection state is detected, the electric compressor is stopped.

[0013]

The present invention protects as described above. (1) Among the components of the electric compressor, the winding temperature of the motor, which has the highest temperature, is continuously detected to detect the high temperature state. At times, the rotation speed of the electric compressor is first limited without stopping the electric compressor, so that it is possible to prevent the passenger from becoming uncomfortable due to large changes in the room temperature and the blowout temperature.

Further, since the electric compressor is stopped when a further dangerous high temperature state is detected or when an abnormal low temperature state is detected, the electric compressor can be reliably protected from the high temperature state with high accuracy. Also, it is possible to prevent the compressor from being broken due to liquid compression or poor lubrication function.

(2) Among the constituent parts of the electric compressor, the winding temperature of the motor, which is the highest temperature, is continuously detected, and when a high temperature state is detected, the electric compressor is not stopped,
First, since the rotation speed of the electric compressor is limited, it is possible to prevent the passenger from becoming uncomfortable due to large fluctuations in the room temperature and the blowout temperature.

Further, since the electric compressor is stopped when a further dangerous high temperature state is detected, the electric compressor can be reliably and accurately protected from the high temperature state.

(3) Among the components of the electric compressor, the winding temperature of the motor, which is the highest temperature, is continuously detected, and when a high temperature state is detected, the electric compressor is not stopped,
First, since the rotation speed of the electric compressor is limited, it is possible to prevent the passenger from becoming uncomfortable due to large fluctuations in the room temperature and the blowout temperature.

When a further dangerous high temperature state is detected, the electric compressor is stopped, so that the electric compressor can be reliably and accurately protected from the high temperature state.

Since the electric compressor is stopped when the disconnection state of the temperature sensor is detected, the electric compressor can be surely protected even if the temperature sensor fails.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An electric compressor protecting method and an apparatus having the same according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a protective device for an electric compressor according to an embodiment of the present invention in an electric vehicle.
The battery 1 is a power source for driving the traveling motor 2 of the electric vehicle, and at the same time, a power source for driving the electric compressor 3 for compressing the refrigerant for air conditioning. The inverter 4 converts a DC voltage from the battery 1 into a variable voltage and a pseudo AC voltage having a variable frequency, and drives the electric compressor 3 at a variable rotation speed according to a set rotation speed output from the air conditioning control unit 5. ing. The air conditioning control unit 5 controls the rotational speed of the electric compressor 3 and other various actuators 8 in accordance with environmental conditions detected by various setting devices 6 and sensors 7 in order to make the passenger compartment comfortable. , The air outlet, suction port, air volume, etc. are controlled.

The temperature sensor 9 in the electric compressor 3 is a thermistor, which continuously detects the temperature of the stator winding 10 of the motor and outputs a temperature signal to the inverter 4. Here, the temperature of the stator winding 10 is detected as
Among the components of this electric compressor 3, including the compression section,
This is because the stator winding 10 is the most thermally weak and has a high temperature.

Usually, a winding of insulation class E to H is used for this winding, and the heat resistance temperature is around 130 (° C.).

FIG. 4 is a flow chart of a method for protecting an electric compressor according to an embodiment of the present invention. Winding temperature is 120
When the temperature exceeds (° C.) or higher (however, less than 130 (° C.)), first, the rotation speed is limited without stopping the compressor (steps 101 and 102). And the winding temperature is 100 (℃)
The rotation speed is kept limited until it becomes less than (steps 103 and 104). When the winding temperature becomes lower than 100 (° C.), the rotation speed is restored (steps 103, 1).
05).

Normally, this control alone can protect the compressor from overheating without stopping it, but if the motor is locked or the outdoor fan fails, the Since the line temperature may increase even during the rotation speed limitation and exceeds 130 (° C.), in this case, by stopping the compressor, it is possible to protect from an abnormal state (steps 106 and 107). Although not shown in the figure, when a break in the thermistor is detected during operation of the compressor, the temperature is erroneously detected on the low temperature side by stopping the compressor, and the operation of the compressor may continue. Can be prevented.

FIG. 5 shows the protection regarding the low temperature condition.
As shown in, when the air conditioner is operated from the non-operating state, if the winding temperature (equal to the compressor temperature) becomes less than -20 (° C), the compressor is stopped and another auxiliary By operating the heating device (steps 201, 20
2, 203), it is possible to protect the compressor from liquid compression and defective lubrication function while maintaining the heating function.

[0027]

As described above, the method for protecting an electric compressor and the device having the same according to the present invention include: (1) a temperature sensor for compressing a refrigerant for air conditioning to detect a motor and a winding temperature of the motor. A first setting for detecting a high temperature state of the winding, and a higher temperature state than the first setting are detected by a protection method when an electric compressor having a built-in motor is controlled by an inverter at a variable rotation speed. It has a second setting and a third setting for detecting a low temperature state of the winding, and when the winding temperature exceeds the first setting, the rotation speed of the electric compressor is limited, Since the electric compressor is stopped when the line temperature exceeds the second setting or becomes smaller than the third setting, the room temperature and the blowout temperature fluctuate significantly due to overheating of the compressor, which makes passengers uncomfortable. To ensure high accuracy at the same time. It is possible to protect the electric compressor from a warm state, and to prevent the compressor from being broken due to liquid compression or poor lubrication function when the compressor is operated to a very low outside air temperature by heat pump heating.

(2) A protection method for controlling an electric compressor, which compresses a refrigerant for air conditioning and has a motor and a temperature sensor for detecting a winding temperature of the motor, at a variable speed with an inverter. A first setting for detecting a high temperature state of the winding, and a second setting for detecting a higher temperature state than the first setting, and when the winding temperature exceeds the first setting. The rotation speed of the electric compressor is limited, and the electric compressor is stopped when the winding temperature exceeds the second setting. Prevent it from becoming uncomfortable,
At the same time, the electric compressor can be reliably and accurately protected from a high temperature state.

(3) A protection method for controlling an electric compressor, which compresses an air-conditioning refrigerant and incorporates a motor and a temperature sensor for detecting the winding temperature of the motor, at a variable speed with an inverter. A first setting for detecting a high temperature state of the winding, a second setting for detecting a higher temperature state than the first setting, and a fourth setting for detecting a disconnection state of the temperature sensor. However, when the winding temperature exceeds the first setting, the rotational speed of the electric compressor is limited, and the winding temperature exceeds the second setting, or the fourth setting of the temperature sensor When the disconnection state is detected, the electric compressor is stopped, so that it is possible to prevent the room temperature and the blowout temperature from fluctuating greatly and causing the passenger to feel uncomfortable due to the overheating of the compressor, and at the same time, reliably and accurately from the high temperature state. Protect the electric compressor, Even if the temperature sensor has failed can be protected reliably electric compressor.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of a protection device for an electric compressor according to an embodiment of the present invention.

FIG. 2 is a conventional compressor protection device for an engine-driven automobile.

[Figure 3] Room air conditioner compressor protection device

FIG. 4 is a flowchart of a method for protecting an electric compressor according to an embodiment of the present invention.

FIG. 5 is a flowchart of a method for protecting an electric compressor according to an embodiment of the present invention.

[Explanation of symbols]

 1 Battery 2 Traveling Motor 3 Electric Compressor 4 Inverter 5 Air Conditioning Control Unit 6 Setting Device 7 Sensor 8 Actuator 9 Temperature Sensor (Thermistor) 10 Stator Winding 11 Conventional Automotive Compressor 12 Bimetal SW 13 Clutch 14 Belt 15 Conventional Electric compressor

Claims (3)

[Claims] 1. A protection method for controlling an electric compressor, which compresses a refrigerant for air conditioning and has a motor and a temperature sensor for detecting a winding temperature of the motor, at a variable rotation speed by an inverter, It has a first setting for detecting a high temperature state of the winding, a second setting for detecting a higher temperature state than the first setting, and a third setting for detecting a low temperature state of the winding. When the winding temperature exceeds the first setting, the rotation speed of the electric compressor is limited, and when the winding temperature exceeds the second setting or becomes smaller than the third setting, the electric A method for protecting an electric compressor that stops a compressor, and an apparatus having the same. 2. A protection method for controlling an electric compressor, which compresses an air-conditioning refrigerant and has a motor and a temperature sensor for detecting a winding temperature of the motor, at a variable speed with an inverter. It has a first setting for detecting a high temperature state of the winding, and a second setting for detecting a higher temperature state than the first setting, and when the winding temperature exceeds a first setting, A method for protecting an electric compressor, which limits a rotation speed of the electric compressor, and stops the electric compressor when the winding temperature exceeds a second setting, and an apparatus having the method. 3. A protection method for controlling an electric compressor, which compresses an air-conditioning refrigerant and has a motor and a temperature sensor for detecting a winding temperature of the motor, at a variable speed with an inverter. It has a first setting for detecting a high temperature state of the winding, a second setting for detecting a higher temperature state than the first setting, and a fourth setting for detecting a disconnection state of the temperature sensor. When the winding temperature exceeds the first setting, the rotation speed of the electric compressor is limited, and the winding temperature exceeds the second setting, or the temperature sensor is disconnected at the fourth setting. A method for protecting an electric compressor, which stops the electric compressor when a state is detected, and an apparatus having the same.