JP3243934B2 - Automotive air conditioners - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner for a motor vehicle equipped with a heat pump heating device using a permanent magnet having an irreversible demagnetization phenomenon for a rotor of an electric compressor.

[0002]

2. Description of the Related Art Conventionally, heat pump type heating devices have been mainly used for room air conditioners. However, in the case of heat pump heating, when the difference between the evaporation temperature of the refrigerant and the outside air temperature becomes small, it becomes difficult to remove heat from the outside air. The capacity is reduced and the lowest usable temperature is at most for R22 refrigerant-
It was about 10 (° C.). Therefore, in extremely cold regions, heat pump heaters were rarely sold or used. In such an extremely cold region, a combustion-type heating device is often used.

FIG. 2A is a magnetic field-flux density characteristic diagram showing a relationship between an external magnetic field and an internal magnetic flux density of a ferrite permanent magnet often used for an electric compressor. As shown in FIG. There is a region and a demagnetization region, and the magnetic field at point A is the demagnetization limit magnetic field at room temperature. Therefore, when operating as a motor, a minus magnetic field always acts. However, if this minus magnetic field becomes larger than the demagnetization limit magnetic field at point A, the permanent magnets are demagnetized, and the motor performance deteriorates. Then, in the worst case, the electric compressor cannot be driven. The magnetic field at the demagnetization limit becomes smaller as the temperature becomes lower (moves to the point B side). That is, demagnetization is likely to occur. The magnitude of the negative magnetic field depends on the current flowing through the motor stator. FIG. 2B shows the relationship between the temperature and the demagnetizing current.

[0004]

[Table 1]

Here, in the case of a conventional room air conditioner,
As shown in the room air conditioner column of Table 1, the demagnetizing current determined from the minimum condition of the assumed operating temperature is sufficiently larger than the current capacity of the inverter, so that overcurrent protection for inverter protection is performed. Thus, protection against demagnetization of the permanent magnet was also achieved at the same time.

In recent years, a heat pump type air conditioner equipped with an electric compressor has been commercialized in an electric vehicle, but there has been no method considering protection against demagnetization of a permanent magnet of the electric compressor.

[0007]

However, when a heat pump type heating device is mounted on an automobile, the minimum usable temperature of the heat pump heating is not so different from that of the current room air conditioner in the current state of the art. , The heat pump heating device may be operated in extremely cold regions. For example, when moving from a flatland to a mountainous area, or when moving from Honshu to Hokkaido in Japan.

[0008] Separately, current heat pump heating devices are:
Heating capacity can be secured only up to about -10 (° C),
In the future development of technology for automobiles, it is strongly required to secure heating capacity even at lower temperatures, and if this is realized, there is a possibility that heat pump heating devices can be operated in extremely cold regions .

When the heat pump type heating device is operated in such an extremely cold region, the above-described demagnetizing current becomes smaller than the current capacity of the inverter (see the car air conditioner column in Table 1). There is a problem that the motor-driven compressor does not function due to the demagnetization of the motor only by the overcurrent protection for protecting the inverter.

[0010] Then, in mounting the air conditioning system electric compressor using such permanent magnets, the cold land, there is a problem that the it is possible to not come to heating.

[0011] The present invention is intended to solve the above problems, an automobile by operation of the heat pump type heating apparatus in cold land, motor of the electric compressor is demagnetized, that abolish proof that the electric compressor does not function The purpose is to supply air conditioners for use.

[0012]

In order to solve the above problems, an automotive air conditioner according to the present invention comprises: (1) a motor in which a refrigerant of a heat pump type heating device is compressed and a rotor is constituted by a permanent magnet. A built-in electric compressor, an inverter for energizing the motor and driving the electric compressor at a variable speed, a temperature detecting means for detecting an internal or ambient environment temperature of the electric compressor, and the temperature detecting means A control unit for stopping the power supply to the motor of the electric compressor when the temperature detected in step (b) becomes lower than a predetermined value.

(2) An electric compressor having a built-in motor in which a rotor is constituted by permanent magnets, and a motor is energized by compressing the refrigerant of the heat pump type heating device, and the electric compressor is driven at a variable speed. An inverter to be driven, temperature detecting means for detecting an internal or ambient environmental temperature of the electric compressor,
A heating device different from the heat pump heating device, and when the temperature detected by the temperature detection unit is lower than a predetermined value, the power supply to the motor of the electric compressor is stopped, and the heat pump heating device Is provided with a control unit for operating a different type of heating device.

(3) An electric compressor having a built-in motor whose rotor is constituted by permanent magnets and a motor being energized by compressing the refrigerant of the heat pump type heating device and rotating the electric compressor at a variable speed. An inverter to be driven, current detection means for detecting a current flowing through the inverter or the motor,
Temperature detecting means for detecting the internal or ambient environmental temperature of the electric compressor, and determining that an overcurrent has occurred when the current has exceeded a set value, stopping the power supply to the motor of the electric compressor, Is set in accordance with the temperature detected by the temperature detecting means.

(4) Means for Solving the Problems The vehicle air conditioner described in (3) is provided with a heating device different from the heat pump type heating device, and the electric compressor is operated by the overcurrent protection means. When stopped, a control unit is provided for operating a heating device different from the heat pump heating device.

(5) A vehicle air conditioner according to the means (2) and (4) for solving the above-mentioned problem, wherein a heating system different from the heat pump heating system is a combustion heating system. It is.

[0017]

According to the present invention, (1) when the temperature detected by the temperature detecting means becomes lower than a predetermined value, the energization of the motor of the electric compressor is stopped, so that the demagnetizing current or more is reduced. Current does not flow through the motor, and demagnetization of the motor of the electric compressor in extremely cold regions can be prevented.

(2) When the temperature detected by the temperature detecting means becomes lower than a predetermined value, by stopping the power supply to the motor of the electric compressor, a current higher than the demagnetizing current flows to the motor. In addition, demagnetization of the motor of the electric compressor in extremely cold regions can be prevented. At the same time, since a heating device different from the heat pump heating device is operated, the heating function does not stop.

(3) Since the set value of the overcurrent is changed according to the temperature detected by the temperature detecting means, the demagnetization current does not become smaller than the set value of the overcurrent even in a low temperature state. Also, when the current exceeds the set value of the overcurrent, the energization of the motor of the electric compressor is stopped.Therefore, the current exceeding the demagnetizing current does not flow to the motor, and the motor of the electric compressor in extremely cold regions Can be prevented from demagnetizing.

(4) Since the set value of the overcurrent is changed according to the temperature detected by the temperature detecting means, the demagnetization current does not become smaller than the set value of the overcurrent even in a low temperature state. Also, when the current exceeds the set value of the overcurrent, the energization of the motor of the electric compressor is stopped.Therefore, the current exceeding the demagnetizing current does not flow to the motor, and the motor of the electric compressor in extremely cold regions Can be prevented from demagnetizing. At the same time, since a heating device different from the heat pump heating device is operated, the heating function does not stop.

(5) Since the set value of the overcurrent is changed according to the temperature detected by the temperature detecting means, the demagnetizing current does not become smaller than the set value of the overcurrent even in a low temperature state. Also, when the current exceeds the set value of the overcurrent, the energization of the motor of the electric compressor is stopped.Therefore, the current exceeding the demagnetizing current does not flow to the motor, and the motor of the electric compressor in extremely cold regions Can be prevented from demagnetizing. At the same time, since the combustion-type heating device is operated, the heating function does not stop.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an air conditioner for a vehicle according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram of an air conditioner for a vehicle according to an embodiment of the present invention in an electric vehicle.

The battery 1 is a power source for the motor 2 for driving the automobile and also a power source for the electric compressor 3 for air conditioning. The motor of the electric compressor 3 includes a stator winding 4 and a ferrite-based permanent magnet 5 (rotor). The temperature detecting means 6 is a thermistor, which detects the temperature of the motor part of the electric compressor 3 and outputs the signal of the temperature to the overcurrent protection means 10.
Is output to the control unit 8. This temperature detecting means 6 may be a bimetal SW or a thermocouple thermometer.

The inverter 7 converts the DC voltage from the battery 1 into a variable AC voltage based on a command from the control unit 8 and changes the applied voltage to change the electric compressor 3 to a variable speed. Driving. Here, the switching element of the inverter 7 includes a power transistor and an I
GBTs and MOSFETs are used.

The current detecting means 9 detects a DC current flowing through the inverter and outputs a signal to the overcurrent protection means 10. Here, the DC-CT
(DC current sensor), a shunt resistor, and the like are used.

The overcurrent protection means 10 changes the set value of the overcurrent in accordance with the temperature detected by the temperature detection means 6, and when the current detected by the current detection means 9 exceeds the set value. It determines that an overcurrent has occurred and outputs a stop signal to the control unit 8. Then, upon receiving the stop signal, the control unit 8 turns off all the switching elements 11 and turns off the electric compressor 3.
When the power supply to the heater is stopped, the combustion type heater 12 is operated at the same time.

The combustion heater 12 obtains thermal energy by burning fossil fuel or the like, and is an oil fan heater, an oil stove, a heating device using gasoline as fuel, or the like. Further, a heating device such as an electric heater may be used instead of the combustion type heater. FIG. 4 shows an example of an electric circuit diagram of the current detection means 9 and the overcurrent protection means 10.

FIGS. 3A and 3B are control flowcharts showing the control flow in the control unit 8 and the overcurrent protection means 10. The operation of the air conditioner for a vehicle according to one embodiment of the present invention will be described below. This will be described with reference to FIGS.

First, when the compressor temperature is -20 (° C.) or higher, the overcurrent is set to 30 (A) (step 1).
01, 102). If the compressor temperature is lower than −20 (° C.) and higher than −40 (° C.), the overcurrent setting is set to 20.
(A) (steps 101, 103, 104). Under the condition that the above-mentioned compressor temperature is −40 (° C.) or more, the actual current is compared with the set value of the overcurrent, and when the actual current exceeds the set value of the overcurrent, the compressor is stopped. Then, the combustion type heater is turned on (steps 107 and 10).
5, 106). Also, when the compressor temperature is lower than −40 (° C.), the compressor is stopped and the combustion heater is turned on (steps 103, 105, and 106).

By controlling in this way,
Even when the temperature changes, the set value of the overcurrent is changed accordingly, so that the demagnetizing current does not become smaller than the set value of the overcurrent, and the current that is higher than the demagnetizing current is supplied to the compressor motor. It does not flow and demagnetization of the motor can be prevented. Further, since the combustion type heater capable of obtaining a sufficient heating capacity even at extremely low temperatures is operated, the heating function is maintained and no serious accident occurs. FIG. 3 described above.
The control of (A) is effective when the lowest usable temperature of the heat pump heating device is expanded to a lower temperature side due to future technical development.

When the compressor temperature is about -10 (.degree. C.), which is the same as the current level, as shown in FIG.
(° C), the compressor may be stopped and the combustion type heater may be turned on (step 20).
1, 202, 203).

[0033]

As described above, the automotive air conditioner of the present invention comprises: (1) an electric compressor having a built-in motor in which a refrigerant of a heat pump type heating device is compressed and a rotor is constituted by a permanent magnet; An inverter that energizes a motor and drives the electric compressor at a variable speed; temperature detection means for detecting an internal or ambient environmental temperature of the electric compressor; and a temperature detected by the temperature detection means that is a predetermined value. When the temperature becomes lower, the control unit for stopping the power supply to the motor of the electric compressor is provided. Therefore, even when the heat pump heating device is operated in an extremely cold region, the motor of the electric compressor is demagnetized. However, it is possible to prevent the electric compressor from functioning.

(2) The compressor of the heat pump type heating device is compressed, and an electric compressor having a built-in motor whose rotor is constituted by a permanent magnet is supplied to the motor, and the motor is energized at a variable speed. An inverter to be driven, temperature detecting means for detecting an internal or ambient environmental temperature of the electric compressor,
A heating device different from the heat pump heating device, and when the temperature detected by the temperature detection unit is lower than a predetermined value, the power supply to the motor of the electric compressor is stopped, and the heat pump heating device Since the control unit that operates a heating device that is different from the system is provided, even when the heat pump heating device is operated in extremely cold regions, the motor of the electric compressor is demagnetized and the electric compressor does not function Can be prevented. The heating function stops because another heating device is activated.
Never .

(3) The compressor of the heat pump type heating device is compressed, and an electric compressor including a motor having a rotor composed of a permanent magnet is supplied to the motor, and the motor is energized to drive the electric compressor at a variable speed. An inverter to be driven, current detection means for detecting a current flowing through the inverter or the motor,
Temperature detecting means for detecting the internal or ambient environmental temperature of the electric compressor, and determining that an overcurrent has occurred when the current has exceeded a set value, stopping the power supply to the motor of the electric compressor, Is set in accordance with the temperature detected by the temperature detecting means, so that the motor of the electric compressor is reduced even when the heat pump heating device is operated in an extremely cold region. It is possible to prevent the electric compressor from malfunctioning due to magnetism.

(4) In addition to the means (3) for solving the above-mentioned problem, a heating device different from the heat pump heating device is provided, and the electric compressor is stopped by the overcurrent protection means. When the heat pump heating device is operated in a different region from the heat pump heating device, the control unit operates the heating device in an extremely cold region. Further, it is possible to prevent the electric compressor from functioning. Since another heating system is activated ,
Tuft function does not stop .

(5) Means for Solving the Problems The heating system different from the heating system of the means (2) and (4) is a combustion heating system. Is operated, it is possible to prevent the motor of the electric compressor from being demagnetized and the electric compressor from malfunctioning. In addition, since another heating device is operated, the heating function does not stop.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an air conditioner for a vehicle according to an embodiment of the present invention.

FIG. 2A is a magnetic field-magnetic flux density characteristic diagram of a permanent magnet, and FIG. 2B is a characteristic diagram showing a relationship between a temperature and a demagnetizing current.

3A is a control flowchart of the automotive air conditioner of the present invention, and FIG. 3B is a control flowchart of the automotive air conditioner of the present invention.

FIG. 4 is an electric circuit diagram of current detection means and overcurrent protection means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Battery 2 Running motor 3 Electric compressor 4 Stator winding 5 Permanent magnet (rotor) 6 Temperature detection means 7 Inverter 8 Control part 9 Current detection means 10 Overcurrent protection means 11 Switching element group 12 Combustion heater

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-2-136324 (JP, A) JP-A-5-4511 (JP, A) JP-A-2-225121 (JP, A) JP-A-6-225 72135 (JP, A) JP-A-6-32140 (JP, A) JP-A-61-54313 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60H 1/22

Claims (5)

(57) [Claims] 1. Compressing a refrigerant of a heat pump type heating device,
An electric compressor in which a rotor has a built-in motor composed of a permanent magnet; an inverter that energizes the motor and drives the electric compressor at a variable speed; and an internal or ambient environmental temperature of the electric compressor. An air conditioner for an automobile, comprising: a temperature detecting means for detecting; and a control unit for stopping power supply to a motor of the electric compressor when a temperature detected by the temperature detecting means becomes lower than a predetermined value. 2. Compressing a refrigerant of a heat pump type heating device,
An electric compressor in which a rotor has a built-in motor composed of a permanent magnet; an inverter that energizes the motor and drives the electric compressor at a variable speed; and an internal or ambient environmental temperature of the electric compressor. Temperature detecting means for detecting, and a heating device of a different type from the heat pump heating device, and when the temperature detected by the temperature detecting device becomes lower than a predetermined value, the power supply to the motor of the electric compressor is stopped. An air conditioner for a vehicle, further comprising a control unit for operating a heating device different from the heat pump heating device. 3. Compressing the refrigerant of the heat pump type heating device,
An electric compressor having a built-in motor in which a rotor is constituted by a permanent magnet; an inverter that energizes the motor and drives the electric compressor at a variable speed; and a current that detects a current flowing through the inverter or the motor. Detecting means, temperature detecting means for detecting an internal or ambient environmental temperature of the electric compressor, and determining that an overcurrent is detected when the current exceeds a set value to stop energizing the motor of the electric compressor. In addition, an automotive air conditioner provided with an overcurrent protection means for changing the setting of the overcurrent in accordance with the temperature detected by the temperature detection means. 4. A heating device different from the heat pump heating device is provided, and when the electric compressor is stopped by the overcurrent protection means, a heating device different from the heat pump heating device is operated. The vehicle air conditioner according to claim 3, further comprising a control unit that controls the air conditioner. 5. A vehicle air conditioner according to claim 2, wherein the heating device different from the heat pump type heating device is a combustion type heating device.