JPH11324934A - Air conditioner compressor drive - Google Patents

Abstract

(57) [Problem] To provide a compressor driving device of an air conditioner that heats efficiently from inside the compressor when an ambient environment temperature is low. SOLUTION: In a compressor driving device of an air conditioner that drives a compressor with a three-phase AC voltage converted from a DC power supply 1 by a power supply conversion means 21, during operation stop of the compressor,
A constant AC voltage having a higher frequency than that during normal operation, which cannot be followed by a movable part of the compressor, is applied to the stator winding 14 of the compressor at regular intervals, and the current value at that time is detected by current detection means 24. If the current value exceeds a predetermined set value, it is determined that the compressor is in a low temperature state to be protected, and the high frequency constant AC voltage is continuously applied to the stator winding 14. Heat from inside the compressor. Also,
When the current value becomes equal to or less than the predetermined set value, the continuous application is stopped, and the application is again shifted to the application at regular time intervals to detect the current value. This series of operations is repeated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressor driving device for an air conditioner, particularly to shortening a heating start-up time at a low temperature, protecting a compressor, and saving power.

[0002]

2. Description of the Related Art As is generally known, when an air conditioner is operated for heating at a low temperature, the refrigerant dissolves in lubricating oil in the compressor, so that even when the compressor is driven, the amount of circulating refrigerant is difficult. It does not increase, the heating rise time becomes long, or the lubricating action is hindered, which may adversely affect the compressor.

For this reason, conventionally, in order to avoid the above-mentioned problems, when the ambient temperature of the air conditioner becomes low so as to heat the compressor from the inside, the operation of the compressor is stopped during operation. An AC voltage having a higher frequency than that during normal operation, which cannot be followed by the movable part of the compressor, has been applied to the compressor.

[0004]

In such a conventional compressor drive for an air conditioner, if the ambient environment temperature of the air conditioner is kept low, the compressor is not compressed even after the compressor is sufficiently heated. Although the AC voltage continues to be applied to the compressor and the temperature inside the compressor is sufficiently high and the refrigerant is not sufficiently dissolved in the lubricating oil in the compressor, the ambient temperature around the air conditioner is low. The voltage is continuously applied, the efficiency is low, the power is wasted, and there is a problem that the compressor is excessively heated.

The present invention solves the above problems,
An object of the present invention is to provide a compressor drive device of an air conditioner driven by an inverter, in which the compressor itself is efficiently heated from inside the compressor when the compressor itself is at low temperature. .

[0006]

According to the present invention, there is provided a DC power supply for generating a DC voltage, power supply conversion means for converting the DC voltage into a variable voltage and variable frequency AC power supply, and the power supply conversion means. Signal generating means for outputting a variable voltage signal and a variable frequency signal to the means, and a compressor driven by the power supply converting means and circulating a refrigerant of the air conditioner,
Current detecting means for detecting a value of a current flowing through the compressor, wherein the compressor is configured to stop operating a movable portion of the compressor while the compressor is stopped. The air conditioner is adapted to apply the constant AC voltage to the compressor continuously when the current detecting means detects a current value higher than a predetermined set value. It is a compressor driving device.

According to the present invention, the temperature condition of the compressor is accurately detected directly without using the means for measuring the ambient temperature, and the compressor is heated from the inside when the low temperature condition is detected, so that wasteful power is consumed. Consumption can be reduced.

According to a second aspect of the present invention, there is provided a DC power supply for generating a DC voltage, power supply conversion means for converting the DC voltage into a variable voltage and variable frequency AC power supply, and a variable voltage signal transmitted to the power supply conversion means. A compressor that includes a signal generator that outputs a variable frequency signal, a compressor that is driven by the power supply converter and circulates a refrigerant of the air conditioner, and a temperature detector that detects an ambient temperature of the air conditioner. When the temperature detecting means detects a low temperature state during operation stop,
When the movable part of the compressor cannot follow, a constant AC voltage having a higher frequency than during normal operation is applied to the compressor at regular intervals, and the current detection unit detects a current value higher than a predetermined set value at that time. The present invention provides a compressor driving device for an air conditioner, wherein the constant AC voltage is continuously applied to the compressor.

According to the present invention, since a constant AC voltage is applied so as to detect the temperature state of the compressor only when the ambient environment temperature is low, there is no waste in the temperature detection operation of the compressor, and power consumption is further reduced. Can be reduced.

According to a third aspect of the present invention, when the current detecting means detects a current value equal to or less than a predetermined set value while a constant AC voltage having a higher frequency than the normal operation is continuously applied to the compressor, 3. A compressor driving device for an air conditioner according to claim 1, wherein a series of operations for stopping application of the AC voltage to the compressor and shifting to application at regular time intervals is repeated. .

According to the present invention, it is possible to prevent overheating of the compressor, reduce power consumption, and heat the compressor efficiently.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention according to claims 1 and 2, the DC power supply is means for powering an air conditioner, and is a means for rectifying a commercial AC power supply after rectifying it with a rectifying element and then smoothing the rectified element. It can be realized, but is not limited to this. The power supply conversion means is a power supply means for converting the DC power supply into a variable voltage and variable frequency AC power supply to drive the compressor, and includes a plurality of sets of series circuits of switching elements and a driver circuit for driving them. Although a general inverter configuration may be used, in the present application,
The switching element must have excellent high-frequency characteristics so that the movable part of the compressor cannot output the AC voltage at a higher frequency than normal operation, for example, 25 KHz. However, the configuration is not limited.

[0013] The constant AC voltage is a constant voltage AC within a voltage range that can be supplied by the power supply conversion means. With the AC voltage, the current flowing through the compressor can be detected in correlation with the temperature of the compressor. If the temperature is in a low temperature state, it is sufficient that the AC voltage is sufficient to heat the compressor from the inside by continuous application, and in the embodiment, among the three-phase stator windings of the motor in the compressor, Although a single-phase constant AC voltage is applied to a series circuit of two stator windings, this is a simple embodiment and is not limited to this. Further, the current detecting means means means for detecting the magnitude of the current flowing through the compressor by applying the constant AC voltage, and may be any means as long as the current value can be detected in correlation with the temperature of the compressor. It is not something to be done.

The temperature detecting means in the present invention according to claim 2 is a means for detecting the ambient temperature, and may be any means as long as it can detect the temperature around the compressor, and is not particularly limited. .

In the present invention according to claim 3, the means for stopping the application of the constant AC voltage means means for stopping the heating when the temperature of the compressor is equal to or higher than a predetermined temperature, and means for stopping the application. Is not limited.

Hereinafter, embodiments of the present invention will be described.

[0017]

(Embodiment 1) Hereinafter, Embodiment 1 of a compressor driving device for an air conditioner according to the present invention will be described with reference to the drawings. This embodiment relates to claims 1 and 3.

FIG. 1 is a circuit diagram showing the configuration of this embodiment. In FIG. 1, 1 is a DC power supply, and 2, 3, and 4 are
The transistors each having a collector connected to the positive terminal of the DC power supply 1, and the transistors 5, 6, and 7 having their emitters connected to the negative terminal of the DC power supply 1, respectively, constitute a three-phase bridge. I have. 8,
9, 10, 11, 12 and 13 are fly-hole diodes, which are connected in parallel to the transistors 2 to 7, respectively. Reference numeral 14 denotes a stator winding of a three-phase motor that drives a compressor of an air conditioner, and 15, 16, 17, 18, 19, and 20 denote driver circuits that drive transistors 2 to 7, respectively. The transistors 2 to 7, the fly-hole diodes 8 to 13 and the driver circuits 15 to 20
A power supply conversion means 21 for converting the DC power supply 1 into a variable voltage and variable frequency AC power supply, that is, an inverter is configured.

Reference numeral 22 denotes a signal generation means for generating a signal for controlling the power supply conversion means 21. The signal generation means 22 receives a target operation speed signal corresponding to the air conditioning load output from the operation command means 23, and the compressor operates the target operation speed signal. It outputs signals that control voltage and frequency so that it can be operated with numbers. Reference numeral 24 denotes a current detecting means for detecting a current generated by a voltage supplied to the stator winding 14.

The operation of the above configuration will be described.
The operation pattern during normal operation is as follows. The operation command unit 23 outputs a target operation speed signal according to the air conditioning load to the signal generation unit 22. The signal generating means 22 having received the target operation speed signal inputs a base drive signal for controlling the voltage and frequency of the three-phase AC voltage so that the compressor is operated at the target operation speed.
20 to transistors 2 to 7.

FIG. 2 is a timing chart showing the conductive state of the transistors 2 to 7 corresponding to the base drive signal and the voltage applied to the stator winding 14. In the figure, UH indicates the open / closed state of the transistor 2, and similarly,
VH, WH, UL, VL, and WL indicate the open / closed states of the transistors 3, 4, 5, 6, and 7, respectively. H level indicates ON and L level indicates OFF. VU-V indicates a voltage waveform between the U voltage terminal and the V voltage terminal of the stator winding 14. The same applies to VV-W and VW-U. The time Ti is 7 to 33 msec. The three-phase AC voltages U, V, and W shown in FIG. 2 are applied between the terminals of the stator winding 14 by the base drive signal, and the compressor is operated at a predetermined target operation speed and the cooling ( Heating) capacity is variable. Since these control means are publicly known, detailed description will be omitted.

Next, the operation when the ambient temperature drops while the compressor is stopped will be described. When a certain period of time has elapsed after the compressor stopped, the operation command means 23 outputs a stator winding temperature confirmation command to the signal generation means 22. The signal generating means 22 has a frequency (about 25 kHz) considerably higher than the frequency during normal operation (about 30 to 150 Hz), in which the movable parts of the compressor cannot follow the transistors 2 to 7 via the driver circuits 15 to 20. A base drive signal for supplying a constant AC voltage to the compressor for a fixed time is output. At this time, the current detecting means 24 detects the current flowing through the stator winding 14 and outputs the current to the operation command means 23. Stator winding 1
4 is constant, the temperature of the stator winding 14 can be detected from the current value.

When the current value is equal to or greater than the predetermined set value, the operation command means 23 determines that the temperature is low and outputs a standby operation command to the signal generation means 22. The signal generating means 22 continuously supplies a constant AC voltage having a frequency considerably higher than the frequency during normal operation to the compressor to which the movable parts of the compressor cannot follow the transistors 2 to 7 via the driver circuits 15 to 20. The base drive signal to be supplied is output.
When this base drive signal is applied, an AC voltage having a frequency significantly higher than that during normal operation is applied between the terminals of the stator winding 14 as a result.

FIG. 3 is a timing chart showing the operation of the present embodiment when the compressor is stopped. When a predetermined time has elapsed after the compressor has stopped, the operation command means 23 outputs a stator winding temperature confirmation command to the signal generation means 22. As a result, as shown in FIG. 3A, the constant AC voltage is supplied to the stator winding 14 at regular time intervals Tc.
In this embodiment, the transistors 3, 4, 6 and 7 are driven to open and close by the base drive signal, so that the V
A single-phase high-frequency constant AC voltage Vvw is applied to a series circuit of a winding and a W winding. Note that the transistor 2 and the transistor 5 are kept off. At this time, as shown in FIG.
The value of the current flowing through is detected. This current value is shown in FIG.
Since there is a correlation with the temperature of the stator winding 14 shown in (1), the temperature of the stator winding 14 can be detected from the current value. When the current value exceeds a predetermined set value, it is determined that the stator winding 14 has entered a low temperature state to be protected, and the operation command means 23 issues a standby operation command as shown in FIG. Output. As a result, the constant AC voltage Vvw is continuously applied to the stator winding 14, and the stator winding 14 is energized to heat the compressor from the inside.

With the above operation, when the compressor of the air conditioner is stopped, the low temperature state is detected without detecting the ambient temperature by a thermostat or the like, and the stator winding of the compressor which needs protection is detected. Since the temperature is directly detected and determined, the low temperature state can be accurately detected, and unnecessary power is not consumed. Furthermore, since an AC voltage with a considerably higher frequency is supplied compared to the frequency during normal operation, the audible range is deviated and there is no generation of pseudo-sound, and the frequency is greatly deviated from the resonance frequency of the compressor. Therefore, the rotating part of the compressor does not rotate. The reason why the single-phase AC voltage is adopted is to achieve a simple configuration and reduce power consumption.

When a standby operation command is output to the signal generating means 22 and the signal generating means 22 is continuously supplying the high frequency constant AC voltage to the compressor, FIG.
As shown in (c), the value of the current flowing through the stator winding 14 is detected at regular time intervals Tc, and when the current value falls below the set value, the temperature of the stator winding 14 becomes the protection unnecessary temperature. Is determined, the standby operation stop command is output to the signal generating means 22, and the current supply to the stator winding 14 is stopped. Thereafter, after a certain period of time, a base drive signal is output so as to supply the high frequency constant AC voltage Vvw to the compressor at regular time intervals Tc, and the current detection means 24 detects the current flowing through the stator winding 14. When a current value exceeding the set value is detected, a standby operation command is output to the signal generating means 22 again. The above series of operations is repeated until the compressor is operated.

As described above, according to this embodiment, when the operation of the compressor of the air conditioner is stopped, the constant AC voltage Vvw having a considerably higher frequency than that in the normal operation is applied to the stator winding 14 at regular time intervals Tc. If the current value at that time exceeds a predetermined set value, it is determined that the temperature of the stator winding 14 is in a low temperature state, and the high-frequency constant AC voltage Vvw is continuously applied to compress. By heating the compressor itself, it is possible to accurately detect the temperature of the compressor in a low temperature state and heat the compressor without providing any special temperature detecting means. Further, when the current value becomes equal to or less than a predetermined value, the application of the high-frequency AC voltage is stopped, thereby suppressing unnecessary power consumption and excessively heating the stator winding 14. And reliability can be improved.

In this embodiment, a single-phase high-frequency constant AC voltage is used, but it goes without saying that two-phase or three-phase may be used. It is needless to say that the same effect can be obtained even if the current detecting means 24 is provided at the position shown in FIGS.

(Embodiment 2) Hereinafter, Embodiment 2 of the compressor driving device for an air conditioner of the present invention will be described. This embodiment relates to claims 2 and 3.

FIG. 6 is a circuit diagram showing the configuration of this embodiment. The present embodiment is different from the first embodiment in that a temperature detecting unit 25 for detecting an ambient environment temperature is provided, and an operation command unit 23 is provided only when the ambient environment temperature becomes low while the air conditioner is stopped. A winding temperature confirmation command is output, and thereafter, the same operation as in the first embodiment is performed.

When the temperature detection means 25 detects a low temperature state while the compressor is stopped, the operation command means 23 outputs a stator winding temperature confirmation command to the signal generation means 22. As in the first embodiment, the signal generating means 22 is configured to supply a constant AC voltage having a frequency considerably higher than the frequency during normal operation to the compressor for a certain period of time, which cannot be followed by the movable part of the compressor. Output drive signal. At this time, the current detecting means 24 detects the current flowing through the stator winding 14, and if the current value exceeds a predetermined set value, it is determined that the temperature is low, and a standby operation command is output to the signal generating means 22. . The signal generating means 22 outputs a base drive signal so as to continuously supply a constant AC voltage having a considerably higher frequency than the frequency during normal operation to the compressor, in which the movable portion of the compressor cannot follow, and A constant AC voltage having a frequency considerably higher than the frequency during normal operation is applied to the slave winding 14. Further, even during standby operation, the current value of the stator winding 14 is detected by the current detection means 24, and when the current value falls below the set value, the standby operation is stopped to further reduce power consumption. be able to.

As described above, according to this embodiment, only when the ambient environment temperature becomes low while the compressor is stopped,
Since a command for detecting the temperature of the stator winding 14 of the compressor is output, the stator winding temperature confirmation command is not output when the ambient environment temperature is high, so that the low temperature state can be accurately and efficiently confirmed, and power saving is achieved. Becomes

[0033]

According to the present invention, there is provided a DC power supply for generating a DC voltage, power supply conversion means for converting the DC voltage into a variable voltage and variable frequency AC power supply, and a variable voltage A signal generator for outputting a signal and a variable frequency signal; a compressor driven by the power converter to circulate a refrigerant of the air conditioner; and a current detector for detecting a current value flowing through the compressor. When the compressor is stopped, a constant AC voltage having a higher frequency than that of the normal operation is applied to the compressor at regular intervals. When a current value higher than a set value is detected, the constant AC voltage is continuously applied to the compressor. No temperature detection means is required, and the temperature of the compressor to be protected can be detected directly from the stator windings rather than from the ambient environment temperature.This allows accurate and reliable power saving and efficient heating from inside the compressor. , Can improve the heat retention effect of the compressor, shorten the heating rise time at low temperature, and smooth the lubrication action inside the compressor,
Compressor can be protected.

According to a second aspect of the present invention, there is provided a DC power supply for generating a DC voltage, power supply conversion means for converting the DC voltage into a variable voltage and variable frequency AC power supply, and a variable voltage signal transmitted to the power supply conversion means. A compressor that includes a signal generator that outputs a variable frequency signal, a compressor that is driven by the power supply converter and circulates a refrigerant of the air conditioner, and a temperature detector that detects an ambient temperature of the air conditioner. When the temperature detecting means detects a low temperature state during operation stop,
When the movable part of the compressor cannot follow, a constant AC voltage having a higher frequency than during normal operation is applied to the compressor at regular intervals, and the current detection unit detects a current value higher than a predetermined set value at that time. It is necessary to always detect the stator winding temperature while the compressor is stopped by using a compressor driving device for an air conditioner that continuously applies the constant AC voltage to the compressor. Only when the temperature detecting means detects a low temperature state, the temperature is detected from the current value of the stator winding so as to determine whether or not the compressor needs to be protected. The state can be accurately and reliably detected, and the compressor can be efficiently heated with low power consumption from inside the compressor, thereby protecting the compressor at the time of starting operation at low temperature.

According to a third aspect of the present invention, when the current detecting means detects a current value equal to or less than a predetermined set value while a constant AC voltage having a higher frequency than that of the normal operation is continuously applied to the compressor, 3. A compressor driving device for an air conditioner according to claim 1, wherein a series of operations for stopping application of the AC voltage to the compressor and shifting to application at regular intervals are repeated. Thus, it is possible to prevent an excessive rise in temperature of the compressor, reduce power consumption, and achieve power saving.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of a first embodiment of a compressor driving device for an air conditioner of the present invention.

FIG. 2 is a timing chart showing a transistor conduction state and a voltage applied to a stator winding during normal operation in the embodiment.

FIG. 3 is a timing chart showing an operation of the embodiment while the compressor is stopped.

FIG. 4 is a circuit diagram showing another configuration of the embodiment.

FIG. 5 is a circuit diagram showing another configuration of the embodiment.

FIG. 6 is a circuit diagram showing a configuration of a compressor driving device for an air conditioner according to a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 DC power supply 2,3,4,5,6,7 Transistor 8,9,10,11,12,13 Fly-hole diode 14 Stator winding (compressor) 15,16,17,18,19,20 Driver Circuit 21 Power conversion means 22 Signal generation means 23 Operation command means 24 Current detection means 25 Temperature detection means

Claims (3)

[Claims] 1. A DC power supply for generating a DC voltage, power conversion means for converting the DC voltage into a variable voltage and variable frequency AC power, and outputting a variable voltage signal and a variable frequency signal to the power conversion means. A signal generator, a compressor driven by the power converter, and circulating a refrigerant of the air conditioner, and a current detector for detecting a current value flowing through the compressor, wherein the compressor is stopped during operation. Applying a constant AC voltage of a higher frequency than the normal operation to the compressor at regular intervals, which cannot be followed by the movable part of the compressor,
A compressor driving device for an air conditioner, wherein the constant AC voltage is continuously applied to the compressor when the current detecting means detects a current value higher than a predetermined set value. 2. A DC power supply for generating a DC voltage, power supply conversion means for converting the DC voltage into a variable voltage and variable frequency AC power supply, and outputting a variable voltage signal and a variable frequency signal to the power supply conversion means. A signal generator, a compressor driven by the power converter, and circulating a refrigerant of the air conditioner; and a temperature detector for detecting an ambient temperature of the air conditioner. When the detecting means detects a low-temperature state, a constant AC voltage having a higher frequency than that during normal operation is applied to the compressor at regular intervals, where the movable part of the compressor cannot follow. A compressor driving device for an air conditioner, wherein the constant AC voltage is continuously applied to the compressor when a current value higher than a set value is detected. 3. When the current detecting means detects a current value equal to or less than a predetermined set value while continuously applying a constant AC voltage having a higher frequency than the normal operation to the compressor, the constant AC voltage is applied to the compressor. 3. The method according to claim 1, wherein the application is stopped, and a series of operations for shifting to the application at regular time intervals is repeated.
A compressor drive device for an air conditioner according to any one of the above.