JP3194919B2 - Heating overload control method for air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter air conditioner that varies the operating frequency of a compressor in accordance with cooling or heating capacity. More specifically, the present invention relates to a compressor for an air conditioner that detects a heating overload condition. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating overload control method for an air conditioner, which limits an operating frequency to prevent compressor noise due to variable frequency.

[0002]

2. Description of the Related Art In general, in an air conditioner inverter device, when a temperature (Tp) of an indoor heat exchanger is lower than a release temperature as shown in FIG. When the temperature of the compressor becomes higher than the release temperature after increasing the frequency of the compressor, the current frequency of the compressor is maintained and the temperature increase is suppressed further, and the temperature (Tp) continuously increases due to the heating overload condition and the temperature decreases. At this point, the compressor is protected to lower the temperature by lowering the frequency of the compressor.

At this time, the frequency of the compressor is lowered until the temperature (Tp) of the indoor heat exchanger begins to decrease, and the temperature (Tp) is reduced.
When p) begins to decrease, the compressor frequency is released from falling, and the current frequency of the compressor is maintained. When the temperature falls below the release temperature, the frequency of the compressor is raised again and the indoor heat exchanger is turned off. The frequency of the compressor is variably controlled according to the change in the temperature (Tp).

[0004]

However, in the conventional heating overload control method for an inverter air conditioner configured as described above, a heating overload condition (25 ° C indoor or more, 20 ° C outdoor or more) occurs. Then, the temperature (Tp) of the indoor heat exchanger due to an increase in the internal pressure of the compressor exceeds the maximum reliability guarantee pressure of 27 kg / cm ^2, and the reliability of the compressor is reduced. When the variable frequency control of the compressor is controlled under the conditions, the operating frequency of the compressor is increased or decreased several times in a short time, so that the noise of the compressor due to the variable frequency and the heating performance are reduced. There was a problem that a vertical deviation would occur.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems of the kind described above, and an object of the present invention is to provide a current operation of a compressor when a heating overload condition is detected. In order to minimize the number of times the compressor operating frequency rises / falls by limiting the frequency that is 2Hz lower than the frequency to the maximum frequency, it prevents compressor noise from being generated by changing the frequency, and the vertical deviation of the heating capacity. It is an object of the present invention to provide a heating overload control method for an air conditioner that reduces the load.

[0006]

Means for Solving the Problems A heating overload control method for an air conditioner according to the present invention, which has been made to achieve the above object, comprises a method of controlling an operating frequency of a compressor in accordance with a temperature change of an indoor heat exchanger. An air conditioner control method for performing a heating operation by variably controlling the temperature, wherein an overload condition determining step of determining whether the temperature of the indoor heat exchanger has risen to a temperature lower than or equal to a heating overload condition; and If the temperature of the indoor heat exchanger is equal to or higher than the temperature drop in the condition determination step, a maximum frequency limiting step of setting a frequency lower than the operating frequency immediately before the temperature drop by a predetermined frequency as the maximum frequency of the compressor; A release temperature determining step of determining whether the temperature of the exchanger has dropped below the release temperature; and if the temperature of the indoor heat exchanger is equal to or lower than the release temperature in the release temperature determining step, the temperature of the indoor heat exchanger falls to the release temperature. A time discriminating step of discriminating whether a predetermined time has elapsed until the temperature falls below the release temperature in degrees,
A predetermined frequency elapses in the time discriminating step, a maximum frequency releasing step of resetting a frequency higher than the limited maximum frequency set in the maximum frequency limiting step by a predetermined frequency as a maximum frequency of the compressor. Heating overload control method for an air conditioner.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described below in detail with reference to the accompanying drawings. As shown in FIGS. 2 and 3, the converter means (3) rectifies and smoothes the AC input power supplied from the power input terminal (1) and converts it into DC power. Converted in (3)
DC power is input, converted to a predetermined DC voltage (DC drive power supply of 12 V DC, microcomputer drive power supply of 5 V DC), and output.

[0008] Further, the control means (7) includes the power supply means (5).
The microcomputer that outputs the inverter drive signal by determining the operating frequency of the compressor (13) according to the outdoor conditions and the instructions of the indoor unit, as well as initializing the air conditioner by applying the DC voltage output from the The inverter driving means (9) converts the PWM signal output from the control means (7) to rotate the compressor (13) in accordance with the operating frequency determined by the control means (7), to the inverter driving means. Amplify to signal.

Further, the inverter means (11) turns on or off the six power transistors (TR1 to TR6) alternately in response to a drive signal output from the inverter drive means (9), thereby turning the converter means (11) on. The DC power output from 3) is converted into a 3-phase (u-phase, v-phase, w-phase) AC power and supplied to the compressor (13), and the temperature sensing means (15) detects the indoor temperature, outdoor temperature and This is a thermistor that senses the temperature of the indoor heat exchanger.

Hereinafter, the operation and effect of the heating overload control method for the air conditioner configured as described above will be described. When AC input power is applied from the power input terminal (1), the AC input power is converted to DC power by the converter means (3), and the converted DC power is input to the power means (5) and is supplied to the air conditioner. The power is converted into a microcomputer drive power supply of 5V DC and a load drive power supply of 12V DC required for driving the power supply and supplied to the control means (7) and the inverter drive means (9). Therefore, the control means (7) receives the DC voltage (microcomputer driving power supply) output from the power supply means (5) and initializes the air conditioner.

At this time, the user operates the key operation unit provided on the remote control or the control panel of the indoor unit to press the operation key, and then sets the desired operation mode and the set temperature (T
When s) is input, the control means (7) determines the operating frequency of the compressor (13) according to the outdoor conditions and the instruction of the indoor unit, and outputs an inverter drive PWM signal to the inverter drive means (9).

Thus, the inverter driving means
In (9), the PWM signal output from the control means (7) is amplified and the six power transistors (TR1
~ TR6) are turned on or off alternately by changing the DC power output from the converter means (3) to three-phase AC.
When converted to a power source and output, the compressor (1) is supplied by a three-phase (u-phase, v-phase, w-phase) AC power output from the inverter means (11).
3) rotates.

That is, the inverter means (11) is provided with a compressor corresponding to the cooling or heating capacity required for the operation of the air conditioner.
The operating frequency of (13) and the voltage associated therewith are supplied to the compressor (13) to drive the compressor (13) at a desired operating frequency.

At this time, the operating frequency of the compressor (13) is
It is variably controlled according to the temperature change of the indoor heat exchanger. However, when a heating overload condition (25 ° C indoor or more than 20 ° C outdoor) occurs, the indoor heat exchanger When the temperature rises, the operating frequency of the compressor (13) repeatedly rises and falls in a short time, and heating overload control occurs.

Therefore, in the present invention, when a heating overload condition is detected, control is performed as shown in FIG. 4 so as to limit the operating frequency of the compressor (13) to prevent occurrence of heating overload control. . FIG. 4 is a flowchart showing a heating overload control operation sequence of the air conditioner according to the present invention. In FIG. 4, S represents a step.

First, during the heating operation by driving the compressor (13), the temperature (Tp) of the indoor heat exchanger is sensed by the temperature sensing means (15), and the temperature (Tp) of the indoor heat exchanger is shown in FIG. As shown in the figure, when the operating temperature of the compressor (13) is higher than the release temperature after the operating temperature of the compressor (13) is lower than the release temperature (the temperature preset in the control means, approximately 53 ° C), the frequency rises. Release and compressor
The current operation frequency of (13) is held.

At this time, in step S1, the control means (7) determines that the temperature (Tp) of the indoor heat exchanger continuously rises due to the heating overload condition, and the temperature (Tp) shown in FIG. Temperature, approximately 60 ° C.) or more.

As a result of the discrimination in step S1, if the temperature (Tp) of the indoor heat exchanger is lower than the temperature drop (in the case of NO), the indoor heat exchanger maintains the current operating frequency while maintaining the current operating frequency. Until the temperature (Tp) of the exchanger rises above the drop temperature, the operation from step S1 is repeated.

On the other hand, if the result of determination in step S1 is that the temperature (Tp) of the indoor heat exchanger is equal to or higher than the drop temperature (in the case of YES), the flow proceeds to step S2, where the control means (7) sets the heating overload. The operating frequency immediately before the temperature (Tp) of the indoor heat exchanger rises above the drop temperature when it is determined that overload control has occurred depending on the conditions
While setting the frequency limited by lowering -2 Hz from (the initial frequency shown in Fig. 5) to the maximum frequency (the primary maximum frequency shown in Fig. 5)
Start the counter for 10 minutes.

Next, in step S3, the frequency of the compressor (13) is lowered until the temperature (Tp) of the indoor heat exchanger falls below the falling temperature, as shown in FIG. 5, to protect the compressor (13). ,
In step S4, the control means (7) determines whether the temperature (Tp) of the indoor heat exchanger is decreased as the frequency of the compressor (13) decreases and is lower than the temperature decrease.

As a result of the determination in step S4, if the temperature (Tp) of the indoor heat exchanger is equal to or higher than the drop temperature (in the case of NO), the flow returns to step S3 to change the frequency of the compressor (13) to the indoor heat exchanger. The operation of step S3 and subsequent steps is repeated while lowering the temperature (Tp) until the temperature at which the temperature (Tp) starts to drop below the drop temperature.

On the other hand, if the result of the determination in step S4 is that the temperature (Tp) of the indoor heat exchanger is lower than the temperature drop (in the case of YES), the flow proceeds to step S5, where the frequency of the compressor (13) is reduced. Release the descent and maintain the current operating frequency of the compressor (13) as shown in FIG.

Next, in step S6, the control means (7) determines whether or not the temperature (Tp) of the indoor heat exchanger is continuously reduced and is equal to or lower than the release temperature shown in FIG.

If the result of the determination in step S6 is that the temperature (Tp) of the indoor heat exchanger is higher than the release temperature (in the case of NO), the process proceeds to step S61, where the control means (7) continues the counter. Returning to step S5, the operations in step S5 and subsequent steps are repeated.

On the other hand, if the result of the determination in step S6 is that the temperature (Tp) of the indoor heat exchanger is equal to or lower than the release temperature (in the case of YES), the flow proceeds to step S7, where the control means (7) executes the indoor heat exchange. When the temperature (Tp) of the vessel is equal to or higher than the drop temperature, it is determined whether or not 10 minutes have elapsed until the temperature drops below the release temperature.

As a result of the determination in step S7, if 10 minutes have elapsed (in the case of YES), the flow proceeds to step S8, where the control means (7) determines that the overload control under the heating overload condition has been canceled, and In S2, the frequency higher by +2 Hz than the maximum frequency limited by the overload control (the primary maximum frequency shown in FIG. 5) is reset to the maximum frequency (the initial frequency shown in FIG. 5).

Next, in step S9, the compressor (13)
As shown in FIG. 5, the temperature of the indoor heat exchanger (Tp)
Until the temperature rises above the release temperature, and in step S10, the control means (7) determines that the temperature (Tp) of the indoor heat exchanger is lower than the compressor (1).
It is determined whether the temperature is increased with the increase in the frequency of 3) and is higher than the release temperature.

As a result of the determination in step S10, if the temperature (Tp) of the indoor heat exchanger is lower than the release temperature (NO),
Returning to step S9, the operation of step S9 and subsequent steps is repeated while continuously increasing the frequency of the compressor (13) until the temperature (Tp) of the indoor heat exchanger starts to become higher than the release temperature.

On the other hand, as a result of the determination in step S10,
If the temperature (Tp) of the indoor heat exchanger is higher than the release temperature (YE
In the case of S), the process proceeds to step S11, where the increase in the frequency of the compressor (13) is released, and as shown in FIG.
Returning to step S1, the operation of step S1 and subsequent steps is repeated while maintaining the current operation frequency of 3).

Further, as a result of the determination in step S7, 10
If the time has not elapsed (in the case of NO), the control means (7) proceeds to step S9 and determines the frequency of the compressor (13) while judging that the overload control under the heating overload condition has not been released. As shown in FIG. 5, the operation from step S9 is repeated while the temperature (Tp) of the indoor heat exchanger is increased until the temperature rises to the release temperature or higher.

As described above, the maximum frequency (primary, secondary, tertiary, etc.) of the compressor (13) is generated every time the heating overload control occurs in which the temperature (Tp) of the indoor heat exchanger rises above the drop temperature. As shown in Fig. 5, the operating frequency of the compressor (13) is increased /
The number of descent can be reduced.

Furthermore, the primary, secondary, tertiary, ... maximum frequencies limited by the heating overload control are released at regular time intervals (10 minutes) to return to the initial operating frequency of the compressor (13). Therefore, the operating efficiency of the compressor (13) can be improved.

[0033]

As described above, according to the heating overload control method for an air conditioner according to the present invention, when a heating overload condition is detected, the frequency lowered by 2 Hz from the current operating frequency of the compressor is changed to the maximum frequency. In order to reduce the number of times the compressor operating frequency rises / falls as much as possible, it is possible to prevent compressor noise from being generated due to the variable frequency and reduce the vertical deviation of the heating capacity.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating frequency control of a compressor based on the temperature of a conventional indoor heat exchanger.

FIG. 2 is a block diagram of an inverter device of an air conditioner according to an embodiment of the present invention.

FIG. 3 is a drive circuit diagram of a compressor according to the present invention.

FIG. 4 is a flowchart showing a heating overload control operation sequence of the air conditioner according to the present invention.

FIG. 5 is a diagram showing frequency control of the compressor for controlling the temperature of the indoor heat exchanger according to the present invention.

[Explanation of symbols]

 3 Converter Means 7 Control Means 9 Inverter Driving Means 11 Inverter Means 13 Compressor 15 Temperature Sensing Means

Claims (5)

(57) [Claims] 1. A method for controlling an air conditioner that performs a heating operation by variably controlling an operating frequency of a compressor according to a change in temperature of an indoor heat exchanger, wherein the temperature of the indoor heat exchanger is set to a heating overload condition. An overload condition judging step of judging whether the temperature of the indoor heat exchanger is equal to or higher than the temperature drop in the overload condition judging step of judging whether the temperature has risen above the temperature drop. A maximum frequency limiting step of setting the temperature as the maximum frequency of the compressor, a release temperature determining step of determining whether the temperature of the indoor heat exchanger has dropped below the release temperature, and an indoor heat exchange in the release temperature determining step. If the temperature of the heat exchanger is equal to or lower than the release temperature, a time determining step for determining whether a predetermined time has elapsed until the temperature of the indoor heat exchanger falls to or below the release temperature at the falling temperature; Time A maximum frequency canceling step of resetting a frequency higher than the limited maximum frequency set in the maximum frequency limiting step by a predetermined frequency as the maximum frequency of the compressor when the time has elapsed. Heating overload control method. 2. If the temperature of the indoor heat exchanger is equal to or higher than the temperature drop in the overload condition determining step, the frequency of the compressor is reduced to lower the temperature of the indoor heat exchanger to the temperature lower than the temperature drop,
When the temperature of the indoor heat exchanger falls below the falling temperature,
2. The heating overload control method for an air conditioner according to claim 1, further comprising a frequency variable step of releasing a decrease in frequency and maintaining a current operating frequency of the compressor. 3. The overheating of the air conditioner according to claim 1, wherein the time counter is cleared if the temperature of the indoor heat exchanger is not lower than the release temperature in the release temperature determination step. Control method. 4. The method according to claim 1, wherein the predetermined frequency is in a range of 1 to 3 Hz. 5. The heating overload control method for an air conditioner according to claim 1, wherein the predetermined time is between 5 and 15 minutes.