JP2002106909A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase a current flowing to an armature winding, to perform sufficient heating of a compressor, to improve quick heating ability and to realize high temperature air in a short startup time. SOLUTION: By exciting the two-phase of armature windings 1a, 1b, and 1c, inductance of the armature windings 1a, 1b, and 1c is reduced, and a winding current is increased to heat a compressor 1. Further, the compressor 1 is heated such that by orderly switching an exciting phase, unevenness in a current is approximately equalized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to preheating of an inverter motor used in an air conditioner or the like during standby.

[0002]

2. Description of the Related Art Conventionally, in a refrigeration cycle of an air conditioner or the like, when the atmosphere to which the compressor is exposed becomes low while the compressor is stopped, the refrigerant gas inside the refrigeration cycle is compressed. A so-called sleeping state, which is stored in a liquid state in the machine container, has become a problem. When the compressor is started from the stagnation state, the lubricating oil that originally exists to lubricate sliding parts such as the compression mechanism in the compressor foams with the vaporization and expansion of the refrigerant, and is discharged from the compressor as it is to be frozen. Because it is sent to the cycle, lubricating oil in the compressor is substantially insufficient before returning to the compressor after the refrigeration cycle, and the compression mechanism etc. burns due to friction and may be damaged. It will be lost.

Further, if the liquid refrigerant is laid inside the compressor, the amount of heat is deprived by the vaporization of the liquid refrigerant at the time of starting a heating operation or the like, and the heat radiation from the air conditioner that is originally required by the user is required. , And the heating characteristics at the start are deteriorated.

[0004] Further, at the time of start of sleep, since lubricating oil foaming becomes a problem as described above, it is not possible to control the operating frequency to be raised earlier to obtain a higher temperature sooner. There is a problem that it becomes worse.

[0005] For this reason, conventionally, as one measure to vaporize the liquid refrigerant that has accumulated inside the compressor at the time of starting the compressor and to prevent the above-described foaming from occurring, the compressor is preheated so that the liquid refrigerant is preheated. There is known a method of evaporating as much as possible before starting the compressor.

Here, a conventional compressor preheating method will be described with reference to FIGS. FIG. 10 shows an active converter 6 that converts alternating current to direct current and changes the converted direct current voltage, a three-phase DC brushless motor 11 that drives the compressor 1 (hereinafter, referred to as a motor 11), and a compressor. 1
The upper arm switching element 2a connected between the armature windings 1a, 1b, 1c of FIG.
2b, 2c, lower arm switching elements 2d, 2e, 2f connected between the armature windings 1a, 1b, 1c and the negative side of the DC power supply 3, and a compressor temperature for measuring the temperature of the compressor 1. FIG. 2 is a schematic diagram of an air conditioner including a sensor 51 and an outside air temperature sensor 50 that measures outside air temperature.

In such an air conditioner, the compressor temperature and the outside air temperature detected by the compressor temperature sensor 51 and the outside air temperature sensor 50 are compared with predetermined temperatures respectively set by the microcomputer 4 and the predetermined temperature is determined. If the following is detected, the upper arm switching element 2
a, 2b, 2c and one of the lower arm switching elements 2d, 2e, 2f are turned ON and OFF, and the armature windings 1a, 1b,
A current was passed through 1c to heat the compressor. At this time, the waveform of each winding current flowing through the armature windings 1a, 1b, 1c and the switching elements 2a, 2b, 2c, 2d, 2e,
FIG. 9 shows the gate signal of 2f.

[0008]

However, in the above configuration, when the DC power supply voltage is low, the current flowing through the armature winding is also low, and the compressor cannot be sufficiently heated.
For this reason, the refrigerant has sunk, the rapid warming property has not been improved, and high-temperature air has not been realized in a short rise time. As a countermeasure, there is a method in which the DC power supply voltage is boosted by an active converter to increase the current flowing through the armature winding. However, there is a problem that the operation is likely to be unstable due to a small control power. .

Further, when the magnetic pole position of the rotor of the compressor at the time of stop is indeterminate, the current flowing through the armature winding varies, and there is a problem that the compressor cannot be sufficiently heated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and increases the current flowing through an armature winding, stably and sufficiently heats a compressor, improves fast warming, and reduces the time required for startup in a short time. It realizes high-temperature wind.

Another object of the present invention is to supply a constant winding current even when the current flowing due to the indeterminate magnetic pole position of the rotor of the compressor at the time of stoppage varies.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention reduces the inductance of the armature winding by exciting two phases of the armature winding without increasing the DC voltage. It is characterized in that the compressor is heated by increasing the winding current.

Further, the present invention is characterized in that, by sequentially switching the phases to be excited, variations in current are substantially equalized, and the compressor is stably heated.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS By exciting two phases, the inductance of the armature winding is reduced to 2/3, the armature winding current is increased, and the compressor is heated. Thereby, the winding current can be increased without increasing the DC power supply voltage, and the temperature of the compressor can be increased. In addition, the compressor is sufficiently heated, and when the refrigerant in the compressor stagnates, especially when the outside air temperature is low, such as in winter, the quick warm-up property can be improved and the high-temperature air can be blown out in a short time when the compressor starts up. Improvement can be achieved.

Further, by sequentially switching the phases to be excited, the variation in the current due to the magnetic pole position of the rotor of the compressor when the compressor is stopped can be substantially equalized. That is, a more constant current can flow through each phase, and a stable temperature rise of the compressor can be realized.

Further, by switching the phase to be excited every predetermined time, it is possible to prevent a noise caused by a pulsating flow caused by a variation in current due to a magnetic pole position of the rotor of the compressor when the compressor is stopped.

Further, when a rare earth magnet is used for the rotor of the compressor, the variation of the armature winding current becomes large due to the strong magnetic force. It becomes. That is, regardless of the strength of the magnet used for the rotor of the compressor, it is possible to substantially equalize the variation of the winding current depending on the position of the rotor, and at the same time, to prevent the generation of noise due to pulsating flow. Also, it can reduce noise. Further, it is needless to say that the use of a rare earth motor is very suitable in terms of increasing the efficiency of the compressor.

[0018]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

(Embodiment 1) A first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 shows a compressor 1 having a three-phase DC brushless motor 11 (hereinafter referred to as a motor 11), an active converter 6 for converting AC to DC and varying the converted DC voltage, and a DC power supply 3 Arm switching elements 2a, 2b, 2c connected between the positive electrode side of the armature and the armature windings 1a, 1b, 1c of the compressor 1;
b, 1c and the lower arm switching elements 2d, 2e, 2f connected between the DC power supply 3 and the negative electrode side;
, The inverter drive unit 2 for driving the compressor 1, the microcomputer 4 for controlling the inverter drive unit 2, the control unit 4a for the switching element, the outside air temperature sensor 50 for detecting the outside air temperature, and the temperature of the compressor 1. This is an air conditioner including a compressor temperature sensor 51 for detecting a compressor temperature. In order to detect the stagnation state, at least the outside air temperature sensor 50 is required. For more accurate determination, if the compressor temperature sensor 51 is provided as described above, the temperature state of the compressor can be directly measured. I can judge. Further, the compressor temperature sensor 51 may be replaced by a discharge temperature sensor. In this case, the accuracy of the stagnation determination may be slightly reduced, but the discharge temperature sensor is used for controlling the compressor frequency and the opening degree of the expansion valve. Since it is also used, the cost can be reduced by sharing it. Hereinafter, an example using an outside air temperature sensor and a compressor temperature sensor will be described.

In the air conditioner configured as described above, when the microcomputer 4 detects that the compressor temperature is equal to or lower than the preset temperature Tc and the outside air temperature is equal to or lower than the preset To separately from Tc, the switching is performed. (1) The upper arm switching element 2a and the lower arm switching elements 2e and 2f are turned on by the element controller 4a,
Turn off (2) Upper arm switching element 2b
And the lower arm switching elements 2f and 2d are turned ON, OF
F, (3) ON / OFF the upper arm switching element 2c and the lower arm switching elements 2d and 2e, (4) ON / OFF the upper arm switching elements 2a and 2b and the lower arm switching element 2f.
(5) Turn ON / OFF the upper arm switching elements 2b and 2c and the lower arm switching element 2d. (6)
(1) to turn on and off the upper arm switching elements 2c and 2a and the lower arm switching element 2e
One of the controls in (6) is performed.

Thus, the winding current di, time dt,
Assuming that the voltage V between terminals and the inductance L of the armature winding, di = dt × V / L, the inductance L is 2/3, and the current flowing through the armature winding is 3/2.
Double. Therefore, as compared with the control as in the conventional example, the compressor 1 is heated by the square of the current, that is, 9/4 times the electric power, and as a result, the temperature of the compressor 1 is increased. FIG. 2 shows respective winding currents flowing through the armature windings 1a, 1b, 1c at this time.

(Embodiment 2) A second embodiment of the present invention will be described with reference to FIGS. 1, 3, 4, and 5. FIG. The control circuit diagram of the compressor drive unit of the air conditioner of the second embodiment is the same as that of the first embodiment as shown in FIG.

In the air conditioner, the temperature of the compressor is Tc
Hereinafter, when the outside air temperature is detected to be equal to or lower than To, the control unit 4a of the switching element applies a current to the armature winding by one-phase or two-phase excitation to heat the compressor. At this time, even if the winding current flows, the magnetic pole position of the rotor of the compressor 1 is uncertain and the flowing current varies as shown in FIG. 3, but the upper arm switching element 2a and the lower arm switching element 2e or ON, 2e and 2f, O
After FF, lower arm switching element 2d and upper arm switching element 2b or 2b and 2c are
N, turn off, sequentially upper arm switching element 2b
And lower arm switching element 2f or 2f and 2d
After turning ON and OFF, the lower arm switching element 2d
And the upper arm switching element 2b or 2b and 2
c is turned on and off, and the upper arm switching element 2c and the lower arm switching elements 2d and 2e are sequentially turned on,
After being turned off, the lower arm switching element 2f and the upper arm switching element 2a or 2a and 2b are turned on,
By switching the armature windings 1a, 1b, and 1c that sequentially pass current in a state of one-phase or two-phase excitation to be turned off, variations in the winding current flowing through the armature windings 1a, 1b, and 1c are substantially equalized. The temperature of the compressor 1 is increased. However, in this case, since the current flowing as shown in FIGS. 4 and 5 becomes a pulsating flow, when the carrier frequency is 15 kHz and the cycle is 1/15 × 10 −3 sec, one cycle is 1/5 × 10 3 Because of -3 sec, noise due to pulsating flow may occur.

(Embodiment 3) A third embodiment of the present invention will be described with reference to FIG. 1, FIG. 6, FIG. 7, and FIG. Example 3
The control circuit diagram of the compressor drive unit of the air conditioner of FIG.

In FIG. 6, when it is detected that the compressor temperature is equal to or lower than Tc (step 100) and the outside air temperature is equal to or lower than To (step 101), the controller 4a of the switching element controls the motor by one-phase or two-phase excitation. Child windings 1a, 1b,
An electric current is applied to 1c to heat the compressor 1. At this time, the magnetic pole position of the rotor 10 of the compressor 1 is uncertain and the flowing current varies, but the upper arm switching element 2
a, the lower arm switching element 2e or 2e and 2f are turned ON and OFF (step 102), and the lower arm switching element 2d and the upper arm switching element 2b
Alternatively, 2b and 2c are turned ON and OFF (step 1
03), repeated for a predetermined time t (step 104),
After that, the upper arm switching element 2b and the lower arm switching element 2f or 2f and 2d are turned ON, OF
F (step 105), the lower arm switching element 2e and the upper arm switching element 2c or 2c
And 2a are turned ON and OFF (step 106) and repeated for a predetermined time t (step 107), and thereafter, the upper arm switching element 2c and the lower arm switching element 2d or 2d and 2e are turned ON and OFF (step 108). ), The lower arm switching element 2f and the upper arm switching element 2a or 2a and 2b are turned ON,
A series of operations of turning OFF (step 109) and repeating for a predetermined time t (step 110) are repeated, and by switching the armature windings 1a, 1b, and 1c through which current flows sequentially, one-phase excitation or two-phase excitation is performed. A current is applied to the armature windings 1a, 1b, 1c of the motor 11 in the excited state. Since the rotor 10 of the compressor 1 uses a rare earth magnet, the magnet is strong and the variation in current due to the position of the magnetic pole is large. Since the time t is set in seconds, the generation of noise due to the pulsating flow described in the second embodiment is also prevented, and the temperature of the compressor 1 is increased. FIGS. 7 and 8 show the respective winding currents flowing through the armature windings 1a, 1b and 1c at this time.

[0027]

As is apparent from the above description, according to the present invention, the winding current can be increased without increasing the DC power supply voltage, and the temperature of the compressor can be increased. As a result, the compressor is sufficiently heated, and when the refrigerant in the compressor stagnates, especially when the outside air temperature is low in winter, etc. Improvement can be achieved.

Further, according to the present invention, a constant current can be flowed by switching the armature windings through which the current flows sequentially and making the variation of the winding current depending on the position of the rotor substantially uniform. In addition, a stable compressor temperature rise can be realized.

Further, according to the present invention, by switching the armature windings through which the current flows sequentially by repeatedly setting the switching operation in a very short time, regardless of the strength of the magnet used for the rotor of the compressor, It is possible to make the variation of the winding current depending on the position substantially uniform,
At the same time, the generation of noise due to the pulsating flow is also prevented, so that the noise can be reduced.

[Brief description of the drawings]

FIG. 1 is a control circuit diagram of a compressor drive unit in an air conditioner of the present invention.

FIG. 2 is a diagram showing each winding current waveform and a gate signal of each switching element according to the first embodiment of the present invention.

FIG. 3 is a winding current waveform diagram at each magnetic pole position in Embodiment 2 of the present invention.

FIG. 4 is a winding current waveform diagram in Embodiment 2 of the present invention.

FIG. 5 is a winding current waveform diagram according to a second embodiment of the present invention.

FIG. 6 is a flowchart of a switching element operation according to a third embodiment of the present invention.

FIG. 7 is a winding current waveform diagram according to a third embodiment of the present invention.

FIG. 8 is a winding current waveform diagram according to a third embodiment of the present invention.

FIG. 9 is a diagram illustrating a winding current waveform and a gate signal of each switching element when a conventional air conditioner is open-phase energized.

FIG. 10 is a control circuit diagram of a compressor drive unit in a conventional air conditioner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 10 Rotor 11 Three-phase DC brushless motor 1a Armature winding 1b Armature winding 1c Armature winding 2 Inverter drive part 2a U-phase upper-arm switching element 2b V-phase upper-arm switching element 2c W-phase Arm-side switching element 2d U-phase lower-arm switching element 2e V-phase lower-arm switching element 2f W-phase lower-arm switching element 3 DC power supply 4 Microcomputer 4a Switching element controller 6 Active converter 50 Outside air temperature sensor 51 Compressor Temperature sensor

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuji Tani 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. 72) Inventor Masashi Arakawa 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. CC03 CC08 DD01 EE04 5H560 AA02 BB04 BB12 DC05 EB01 EC02 GG04 JJ06 JJ19 RR10 SS07

Claims (8)

[Claims] 1. A three-phase DC brushless motor for driving a compressor, an armature winding of the motor, a rotor of the motor, a positive pole of a DC power supply of the motor, and an armature winding of the motor. The upper arm switching element connected between the armature winding, the lower arm switching element connected between the armature winding and the negative electrode side of the DC power supply, the control unit of the switching element, and measuring the outside air temperature When the outside air temperature detected by at least the outside air temperature sensor is detected below a predetermined temperature,
The control unit includes one upper arm switching element;
A current is applied to the armature winding by two-phase excitation in which the two lower arm switching elements are turned on and off, or the two upper arm switching elements and the one lower arm switching element are turned on and off. An air conditioner characterized by heating the compressor. 2. A three-phase DC brushless motor for driving a compressor, an armature winding of the motor, a rotor of the motor, a positive pole of a DC power supply of the motor, and an armature winding of the motor. The upper arm switching element connected between the armature winding, the lower arm switching element connected between the armature winding and the negative electrode side of the DC power supply, the control unit of the switching element, and measuring the outside air temperature When the outside air temperature detected by at least the outside air temperature sensor is detected below a predetermined temperature,
The control unit turns on and off one upper-arm switching element and two lower-arm switching elements.
Or turn on and off the two upper-arm switching elements and the one lower-arm switching element.
A method of controlling an air conditioner that heats the compressor by passing a current through the armature winding by two-phase excitation. 3. A three-phase DC brushless motor for driving a compressor, an armature winding of the motor, a rotor of the motor, a positive pole of a DC power supply of the motor, and an armature winding of the motor. And an upper arm switching element connected between the armature winding and the negative electrode side of the DC power supply, a lower arm switching element, a control unit of the switching element, and measuring an outside air temperature. When the outside air temperature detected by at least the outside air temperature sensor is detected to be equal to or lower than a predetermined temperature, the control unit controls the one upper arm switching element and the lower arm switching element 1 ON for 2 or 2
OFF or two or one upper arm switching element and the lower arm switching element 1
An air conditioner characterized by performing one-phase or two-phase excitation for turning ON / OFF a unit, and further switching the armature winding through which current flows sequentially to heat the compressor. 4. A three-phase DC brushless motor for driving a compressor, an armature winding of the motor, a rotor of the motor, a positive pole of a DC power supply of the motor, and an armature winding of the motor. And an upper arm switching element connected between the armature winding and the negative electrode side of the DC power supply, a lower arm switching element, a control unit of the switching element, and measuring an outside air temperature. When the outside air temperature detected by at least the outside air temperature sensor is detected to be equal to or lower than a predetermined temperature, the control unit, the upper arm switching element one,
One or two lower arm switching elements
N or OFF, or two or one of the upper arm switching elements, and one or two phase excitation for turning on and off one of the lower arm switching elements, and furthermore, the armature winding for sequentially passing current. And controlling the air conditioner to heat the compressor. 5. The control unit switches the armature winding through which the current flows for a predetermined time, thereby substantially equalizing the variation in the current due to the position of the rotor, and flowing a constant current through the armature winding to start the compressor. The air conditioner according to claim 1 or 3, wherein the air conditioner is heated. 6. The control unit switches the armature winding through which the current flows by a predetermined time, thereby substantially equalizing the variation in the current due to the position of the rotor, and flowing a constant current through the armature winding to start the compressor. Claim 2 or Claim 4 which heats
The method for controlling an air conditioner according to item 1. 7. The air conditioner according to claim 1, wherein the magnet of the rotor of the compressor is a rare earth. 8. The control method for an air conditioner according to claim 2, wherein the magnet of the rotor of the compressor is a rare earth.