JPH04174242A - Controller for air conditioner - Google Patents

Abstract

PURPOSE:To prevent the unnecessary change-over of a mode that is attributable to overshoot by providing a means for judging whether a compressor is operated and a means for checking the change-over of cooling/heating when said judging means judges the operation of the compressor while a room temperature is in a specified temperature zone. CONSTITUTION:A freezing cycle consists of a compressor 48, a four-way valve 2, an outdoor side heat exchanger 3, a capillary tube 4, an indoor side heat exchanger 5, and an accumulator 6, which are connected in order in the form of ring by a refrigerant pipeline. Provisions are made of a means 12 for judging whether the compressor 48 is operated, and a means for checking the change- over of cooling/heating when the judging means 12 judges the operation of the compressor 48 while a room temperature is in a specified temperature zone. In addition, operation starting/operation stopping is switched by a push type switch 9, and cooling/heating is switched by a change-over switch 10. By this method, even in the case of the overshoot of a room temperature, the unnecessary change-over of cooling/heating is not carried out during the operation of the compressor.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a control device for an air conditioner, and more particularly to an air conditioner in which a compressor of an air conditioner having an automatic cooling/heating switching function is frequency-controlled by an inverter. The present invention relates to a control device.

[Conventional technology]

In general, inverter-controlled air conditioners that have an automatic cooling/heating switching function operate at high frequency at the start of operation until the room temperature in the room to be conditioned approaches the set temperature. When the set temperature is exceeded, control is performed to reduce the control frequency of the compressor by the inverter.

With this type of conventional control, when the air conditioner starts operating,
The control constant is set so that the room temperature sufficiently overshoots, thereby quickly settling the room temperature to the set temperature.

This type of control is intended to intentionally overshoot the room temperature so that the room temperature quickly settles to the set temperature.

FIG. 5 shows an example of how the room temperature t is controlled to the set temperature T by such control.

In this type of conventional air conditioner, as shown in Figure 5,
There are multiple zones A above and below the set temperature T.

B, C, C', B', A' are predetermined,
If the room temperature t enters zone A, for example, the cooling mode is set,
The heating and cooling mode is selected according to the relationship between the room temperature and the zone, such that when the vehicle enters zone A', the heating mode is selected.

[Problem to be solved by the invention]

However, according to this conventional technology, even though the cooling mode must be maintained in the example shown in FIG. A problem occurs in which the mode is switched.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an air conditioner control device that solves the problems of the above-mentioned conventional techniques and prevents unnecessary mode switching due to overshoot.

[Means to solve the problem]

In order to achieve the above object, the present invention increases or decreases the frequency of AC power supplied from the inverter circuit to the compressor so that the difference between the room temperature and the set temperature becomes small during normal times, and also increases or decreases the frequency when air conditioning is started. The room temperature is controlled so that it sufficiently overshoots the set temperature, multiple temperature zones are set based on the set temperature, and when the room temperature is in a specific temperature zone among these multiple temperature zones, a predetermined calculation is performed. In a system that automatically switches between cooling and heating based on the results, the means for determining whether the compressor is operating or not and the means for determining when the room temperature is in a specific temperature zone are separate from the compressor. The present invention is characterized in that it includes means for preventing switching between cooling and heating when operation is determined.

Further, according to another invention, the plurality of temperature zones include a first zone closest to the set temperature above the set temperature, a third zone farthest from the set temperature, and a first zone and a third zone. and a fourth zone below the set temperature that is closest to the set temperature, a sixth zone that is farthest from the set temperature, and between the fourth zone and the sixth zone. A timer that starts timing when the room temperature enters the second zone or the fourth zone and continues timing while the room temperature remains in the second zone or the fifth zone. a first cooling/warming switching means for switching between cooling and heating when the timer measures a predetermined time; a means for resetting the timer when the determining means determines that the compressor is operating; The device is characterized by comprising a second cooling/warming switching means that switches between cooling and heating when the air conditioner enters the third zone or the sixth zone.

Furthermore, according to another invention, there is provided a means for outputting a signal for a certain period of time from the time when the determining means determines that the compressor has stopped, and a means for preventing restart of the compressor while this signal is being outputted. means, wherein the second cooling/warming switching means determines whether the room temperature is in the third zone or the sixth zone when the signal is not output. It is.

[For production]

According to the present invention, switching between cooling and heating is prohibited while the compressor is operating, and the same operating mode is maintained. When the compressor is stopped, automatic cooling/heating switching operation is performed based on the temperature zone to which the room temperature belongs. Therefore, while the compressor is in operation, unnecessary cooling/heating switching is not performed even if the room temperature overshoots. In addition to the above, even if the compressor is stopped, a timer that operates while the compressor is stopped automatically switches cooling/heating based on the second zone and the fifth zone. It is preferable not to do this until the elapsed time has been measured. Furthermore, a signal is output until the compressor is stopped for a certain period of time, and while this signal continues to be output, automatic cooling/heating switching based on the third and sixth zones is performed. It is desirable not to do so.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an air conditioner control device according to the present invention will be described below with reference to the accompanying drawings.

FIG. 2 shows an outline of the air conditioner. In the figure, the refrigeration cycle is constructed by sequentially connecting a compressor 48, a four-way valve 2, an outdoor heat exchanger 3, a capillary tube 4, an indoor heat exchanger 5, and an accumulator 6 in a ring shape through refrigerant piping. There is.

When the four-way valve 2 is in the state shown by the solid line in the figure, the compressor 4
The refrigerant discharged from 8 flows as shown by the solid arrow, condenses in the outdoor heat exchanger 3, and evaporates in the indoor heat exchanger 5 to cool the room. When the four-way valve 2 is in the state indicated by the dotted line in the figure, the refrigerant discharged from the compressor 48 flows as indicated by the dotted arrow, condenses in the indoor heat exchanger 5, and then passes through the outdoor heat exchanger 5. In step 3, it evaporates and heats the room. Note that reference numerals 7 and 8 indicate an outdoor fan and an indoor fan, which blow air to the outdoor heat exchanger 3 and the indoor heat exchanger 5.

FIG. 1 shows a control circuit of an indoor unit used in the above-mentioned refrigeration cycle.

The push-button switch 9 is a switch that outputs a signal to switch between starting and stopping the air conditioner every time it is pressed. The changeover switch 10 is set to cooling mode C1.
This is a switch for switching heating mode H1, cooling/heating mode automatic switching C/H, and ventilation mode F. This changeover switch 10 uses a Gray code switch. The room temperature setting device 11 is a setting device that determines a desired set temperature.

This setting device 11 uses a Gray code switch, and each code has a value of 18 to 28.
The temperature settings are compatible.

A microprocessor (hereinafter referred to as microcomputer) 12 stores a program based on a flowchart described below. Switch 9, selector switch 10, room temperature setting device 1
The pressing and setting state of 1 is the output port R of the microcomputer 12.
1, the signal output from R3 to the input port, 2
, to 4. 3.

J, , J2 are scanned, the microcomputer 12 inputs the data, and stores it in correspondence with a specific address.

The temperature detector 13 has an internal resistance value that changes depending on the temperature, and is provided at a position where it can detect the temperature of the conditioned room. This temperature detector 13 has a negative end connected to an input port A3 (analog input terminal) of the microcomputer, and the other end connected to a constant voltage power supply V. The microcomputer 12 performs the following in each cycle of the program:
A current corresponding to the temperature of the conditioned room is input from the input port A3, and data values based on this current value are A/D (analog/digital) converted and stored. At this time, data values are input multiple times and the average value is stored as the temperature value of the conditioned room, and temperature control is thereafter performed based on this stored value.

Furthermore, although not shown, a wireless remote controller (hereinafter referred to as the remote control) is placed at an arbitrary position within the harmonized room, and this remote controller is equipped with a temperature detector similar to the above. . The microcomputer 12 is
Capture temperature data from the temperature sensor of this remote control,
This temperature data is sent to the temperature detector 1 in the indoor unit.
It can be used for temperature control instead of or in conjunction with the temperature data from 3.

The light emitting elements 14 to 20 for displaying room temperature are 15°C and 15°C, respectively.
17℃, 19℃921℃, 23℃925℃, 27℃
The light emitting element corresponding to the scale closest to the temperature value of the conditioned room lights up. The light emitting element 21 for cold air prevention display lights up when the temperature of the indoor heat exchanger 5 (FIG. 1) falls below a predetermined value during heating operation. This temperature is input to the temperature detector 22 from the input port A4 of the microcomputer 12 using a method similar to the method for inputting the temperature value of the room to be conditioned.

The light-emitting elements 23, 24, and 25 are light-emitting elements for displaying automatic cooling/heating mode switching, cooling mode, and heating mode. There is. These light emitting elements 23,
24 and 25 are lit according to the setting value of the changeover switch 10. Note that when the changeover switch 10 is set to the ventilation mode F, the light emitting element 24 for displaying the cooling mode lights up. The light emitting elements 14 to 21 and the light emitting elements 23 to 25 are
Output ports RQ to R4 of the microcomputer 12 and display port O
It is turned on by dynamic lighting using 06. Note that 26 to 29 are inverting circuits.

The relay 31 controls energization of the indoor fan 8 (FIG. 1). This relay 31 has one end connected to the output port R12 of the microcomputer 12 via the inverting circuit 35, and the other end connected to the output port R12 of the microcomputer 12.
It is connected to a constant voltage circuit of C24 (V).

The serial signal circuit 37 is connected to the output port R of the microcomputer 12.
In response to control data output from the output boat R8, a signal for determining the frequency (target frequency) of AC power to be supplied to the compressor 48 is serially transmitted to the outdoor unit. That is, based on the room temperature and the set temperature, an increase or decrease in frequency is determined by PID control (or by fuzzy inference using the difference between the room temperature and the set temperature and a change in this difference), and a new frequency signal is calculated.

The constants used when calculating the new frequency signal are normally set so that the temperature difference between the room temperature and the set temperature is small, and at the start of air conditioning operation, the room temperature sufficiently overshoots the set temperature and the room temperature is set so that it quickly reaches the set temperature. Note that this sufficient overshoot can also be obtained by adding correction to the set temperature. For example, when operating the air conditioner, set the temperature to 4~
5 degrees lower (correction may be made to set the temperature 6 to 8 degrees higher during heating operation).

The oscillation circuit 38 consists of a crystal oscillator, a resistor, and a capacitor, and receives the reference clock of the microcomputer 12 from the input port 0.
It is given to C31 and 0C83.

In addition, constant voltage V, DC24, V, Vss
Since a normal power supply circuit can be used as the constant voltage circuit that outputs ASS REF, a description thereof will be omitted. vA8 above. .

vREF is the upper limit voltage and lower limit voltage of the A/D conversion operation of the microcomputer 12. The terminal INLT is a power reset terminal, and inputs a signal for resetting the microcomputer 12 when the power is turned on. This signal is activated when the power is turned on.
It may be any type that is output when the output of the power supply circuit exceeds a certain voltage value.

FIG. 3 shows the control circuit of the outdoor unit used in this embodiment.

In the figure, AC 100 is supplied from a commercial power source 41.
The v voltage is input to a full-wave rectifier 45 via a varistor 42, a noise filter 43, and a reactor 44. As the DC output of the full-wave rectifier 45, 280V is obtained by the action of the voltage doubler rectifier 47, and this single-phase DC 280V is input to the three-phase bridge type inverter 46.

Invar, 46 is DC 280■ to effective value 100V
A three-phase alternating current is generated to operate a compressor 48 using a three-phase induction motor. The operating speed of the compressor 48 is determined depending on the output frequency of the inverter circuit 46 (hereinafter referred to as control frequency).

The current detection circuit 49 transmits the current value supplied from the commercial power supply 41 detected by the current transformer 50 to the microprocessor (hereinafter referred to as microcomputer) 51 in the form of digital data.

The microcomputer 51 performs, for example, the following control operation based on the magnitude relationship between the current value data (A) and the set current values (St, S2, s3).

(1) A > s 1 Compression 48 operation stop (2) S ≧ A > 82 Control frequency decrease (3)
S≧A>S3 Control frequency increase prohibited (4) S3≧A Normal operation The compressor temperature sensor 52 detects the temperature of the compressor 48 and notifies the microcomputer 51 of the temperature. The microcomputer 51 controls this compressor temperature (T) and the set compressor temperature (S4.S5.S6).
For example, the following control operation is performed based on the magnitude relationship between

(1) T>S4 Compressor 48 operation stop (2) S4≧T>85 Control frequency decrease (3
)S5≧T>86 Control frequency increase prohibited (4) S6≧T Normal operation serial signal circuit 53 receives control data from indoor unit side serial signal circuit 53 shown in FIG. 1 and transmits it to microcomputer 51. When performing normal operation, the microcomputer 51
compressor 4 according to the control data from the indoor unit.
8 and controls the control frequency.

Such operation control of the compressor 48 by the microcomputer 51 is performed by the switching signal amplifying section 54 receiving a command from the microcomputer 51 and controlling the switching operation of the inverter 46 .

That is, the microcomputer 51 outputs on/off signals for the transistors forming the inverter circuit 46 based on PWM theory in response to the frequency signal sent from the indoor unit.

Relay contact piece 55 and phototriac 56 operate under the control of microcomputer 51. When the relay contact 55 is turned on, the outdoor fan 57 is operated, and when the phototriac 56 is turned on, the four-way switching valve 58 is switched.

FIG. 4 is a flowchart showing the main operations of the microcomputer 12 of the indoor unit shown in FIG. 1 in switching the cooling/heating mode i.

To explain with reference to the same figure, the microcomputer 12 first performs a key scan and selects the operation switch 9 and the changeover switch 10.
and input the pressing and setting state of the room temperature setting device 11. Here, it is assumed that the operation switch 9 is in the operating state and the changeover switch 10 is in the automatic cooling/heating mode switching D/H state.

Furthermore, temperature data is input from the temperature detector 13 or from the remote control to determine the room temperature of the conditioned room (step 1
).

Next, the determined room temperature will be in zones A and B as shown in Figure 5.
, C, C', B', and A', which zone it falls into is determined (step 2). In these zones, if the room temperature is t1 and the set temperature is Ts, zone A is t-T > +3℃, zone B is
+3℃＞t-T＞1.5℃C zone is +1.5℃＞t
-T>O°CC' zone is -1,5℃<t-T<0℃
The B' zone is defined as -3°C<t-T<-1,5°C, and the A' zone is defined as t-T<-3°C.

As a result of the above zone determination, if it is determined that the room temperature t is in the A or A' zone, if the compressor 48 is in operation at that time, the current cooling or heating operation will be continued in the cooling mode or Set the heating mode (
Step 3).

On the other hand, when the compressor 48 is in a stopped state, a timer measures 3 minutes from the time the compressor 48 enters the A or A' zone (step 4). If these 3 minutes have passed while in the A or A' zone, then the A zone (
t>T +3℃), set the cooling mode and A'
If the temperature is in the zone (1<T -3°C), the heating mode is set (step 4). Note that even if the vehicle enters the A or A' zone, the cooling or heating mode will not be switched until 3 minutes have elapsed. Due to the structure of the compressor 48, the compressor 48
This is because it took three minutes to restart the computer.

As a result of the above zone determination, if it is determined that the zone is in B or B', if the compressor 48 is in operation at this time, the cooling mode or heating mode is set to continue the cooling operation or heating operation at that time. (Step 3).

On the other hand, when the compressor 48 is in a stopped state, the timer 2 measures 3 portions and the timer H measures 60 minutes (step 6).

If 60 minutes have passed while in the B or B' zone, then the B zone (T.

+3℃>t>T +1. If the temperature is 5℃), the cooling mode is set, and the temperature is set to B' zone (T -3℃<t<T.

-1.5°C), set the heating mode (step 4.5).

If you subsequently move to Zone A or A', after 3 minutes have passed, including the period you were in Zone B or B', the mode will be set to cooling mode for Zone A, and heating mode for Zone A'. (Step 4.5).

As a result of the zone determination, if it is determined that the system is in zone C or C', the cooling mode or heating mode is set to continue the current cooling or heating operation (step 3).

After selecting the cooling or heating mode in this manner, the control frequency of the compressor 48 is calculated based on the determined room temperature t and the set temperature TS, and is transmitted to the outdoor unit (step 7). In the outdoor unit,
The operating speed of the compressor 48 is controlled by the inverter 46 in accordance with the transmitted control frequency. After transmitting the control frequency, timers I and II are reset (step 8).

As is clear from these descriptions, according to this example,
As long as the compressor 48 continues to operate, the initially set cooling or heating mode will be maintained, and even if the room temperature overshoots and enters the zone opposite to the set temperature, the cooling or heating mode will not be switched. No (step 3). Mode switching is only allowed when compressor 48 is stopped.

In this case, a new mode setting is made and the compressor remains stopped for at least 3 minutes before the compressor operation is restarted (timer I). After these 3 minutes have passed, A, A
' A mode switching decision is made in the zone. Also, B
, The mode switching judgment in the B' zone is made after the operation has been stopped for 60 minutes (timer ■).

〔Effect of the invention〕

As is clear from the above description, according to the present invention, while the compressor is operating, the initially set cooling or heating mode is maintained and mode switching is not performed, so the room temperature is overshot. Even if the compressor is stopped, there is no risk of unnecessary mode switching, and in addition to the above, cooling/heating switching based on the second zone and fifth zone can be performed even if the compressor is stopped. Since the timer that operates while the compressor is stopped does not operate until a predetermined elapsed time has been counted, unnecessary mode switching will not occur even if the room temperature overshoots, and furthermore, A signal is output until the compressor is stopped for a specified period of time, and automatic switching between cooling/heating based on the third and sixth zones is not performed while this signal continues to be output. During this time, even if the room temperature overshoots, unnecessary mode switching will not occur.

[Brief explanation of drawings]

Fig. 1 is a control circuit diagram of an indoor unit of an air conditioner using an embodiment of the present invention, Fig. 2 is a schematic diagram of the refrigeration cycle, Fig. 3 is a control circuit diagram of the outdoor unit of the same, and Fig. 4 is the first
FIG. 5 is a flowchart showing the main operations of the microprocessor shown in FIG. 11... Room temperature setting device, 12... Microprocessor, 13... Temperature detector, 46... Inverter circuit,
48... Compressor, 51... Microprocessor, 5
4...Switching signal amplification section. Applicant's agent Masashi Kushibuchi ￥2 drawings

Claims (1)

[Claims] 1. The frequency of the AC power supplied from the inverter circuit to the compressor is increased or decreased so that the difference between the room temperature and the set temperature is small during normal times, and the frequency is adjusted so that the frequency is adjusted to the room temperature when air conditioning is started. The set temperature is controlled to sufficiently overshoot the set temperature, and a plurality of temperature zones are set based on the set temperature, and when the room temperature is in a specific temperature zone among these plural temperature zones, a predetermined temperature is set. In an air conditioner that automatically switches between cooling and heating based on a calculation result, means for determining whether the compressor is operating or not, and a means for determining whether the room temperature is in a specific temperature zone. and means for preventing switching between cooling and heating when the means for determining whether the compressor is operating. 2. The plurality of temperature zones include a first zone closest to the set temperature above the set temperature, a third zone farthest from the set temperature, and a zone between the first zone and the third zone.
a second zone between the zone, a fourth zone closest to the set temperature below the set temperature, a sixth zone furthest from the set temperature, and and a fifth zone located between the zone of a timer that continues counting the time for a certain period of time; a first cooling/warming switching means that switches between cooling and heating when the timer measures a predetermined time; A claim characterized by comprising means for resetting the time measurement of a timer, and second cooling/warming switching means for switching between cooling and heating when the room temperature enters a third zone or a sixth zone. Item 1. A control device for an air conditioner according to item 1. 3. Means for outputting a signal for a certain period of time from the time when the determining means determines to stop the compressor, and means for preventing restart of the compressor while this signal is being output, 2. The air conditioner according to claim 1, wherein the cooling/warming switching means determines whether the room temperature is in a third zone or a sixth zone when the signal is not output. control device.