JP2919596B2 - Control device for air conditioner - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention 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. Related to a control device.

[Conventional technology]

Generally, an air conditioner of an inverter control type having an automatic cooling / heating switching function operates at a high frequency at the start of operation until the room temperature of the conditioned room approaches the set temperature. When the temperature exceeds the set temperature, control for reducing the control frequency of the compressor by the inverter is performed.

In this type of conventional control, at the start of operation of the air conditioner, a control constant is set so that the room temperature sufficiently overshoots, whereby the room temperature is quickly settled to the set temperature.

This type of control is intended to intentionally overshoot the room temperature, thereby promptly setting the room temperature to the set temperature.

Figure 5 shows an example of how the room temperature t is controlled to the set temperature T _s By such control.

In this type of conventional air conditioner, as shown in FIG. 5, and below the set temperature T _s, a plurality of zones A, B, C, C ' , B',
A 'is predetermined, and if the room temperature t enters zone A, for example, the cooling mode is set. If the room temperature t enters zone A', the heating mode is selected. Has been done.

[Problems to be solved by the invention]

However, according to this conventional technique, for example, the fifth
In the example shown in the drawing, although the cooling mode has to be maintained, there occurs a problem that the mode is switched to the heating mode when the room temperature t largely overshoots to the low temperature side and enters the zone A '.

Therefore, an object of the present invention is to provide a control device for an air conditioner that solves the above-described problems of the conventional technology and prevents unnecessary mode switching due to overshoot.

[Means for solving the problem]

In order to achieve the above object, the present invention increases or decreases the frequency of the AC power supplied from the inverter circuit to the compressor so that the difference between the room temperature and the set temperature is normally reduced, and the frequency is changed when the air conditioning is started. The room temperature is controlled so as to sufficiently overshoot the set temperature, a plurality of temperature zones are set based on the set temperature, and a predetermined calculation is performed when the room temperature is in a specific temperature zone among the plurality of temperature zones. In the automatic cooling / heating switching based on the result, the means for judging whether the compressor is operating and the means for judging when the room temperature is in a specific temperature zone are provided by the compressor. When judging operation, cooling /
Means for preventing switching of heating.

According to another aspect, the plurality of temperature zones are a first zone closest to the set temperature above the set temperature,
A third zone furthest from the set temperature, and a second zone between the first and third zones, and a fourth zone closest to the set temperature below the set temperature;
A sixth zone furthest from the set temperature, and a fifth zone between the fourth zone and the sixth zone, wherein the time is measured from the time when the room temperature enters the second zone or the fifth zone. A timer that starts and continues timing while the room temperature is in the second or fifth zone; and a first cooling / heating switch that switches between cooling and heating when the timer times a predetermined time.
A warm-up switching means; a means for resetting a timer when the judging means judges the operation of the compressor;
And a second cooling / heating switching means for switching between cooling and heating when the vehicle enters the second zone or the sixth zone.

Further, according to another aspect of the present invention, the means for outputting a signal for a certain period of time from when the determination means determines that the compressor is stopped, and prevents the compressor from restarting while this signal is being output. Means, wherein the second cooling / heating switching means performs cooling / heating switching when the signal is not output and the room temperature enters the third zone or the sixth zone. It is assumed that.

(Operation)

According to the present invention, during operation of the compressor, switching between cooling and heating is prohibited, and the same operation mode is maintained. When the compressor is stopped, the cooling / heating automatic switching operation is performed based on the temperature zone to which the room temperature belongs. Therefore, during the operation of the compressor, unnecessary cooling / heating switching is not performed even if the room temperature overshoots. In addition to the above, even when the compressor is stopped, a timer that activates automatic switching between cooling and heating based on the second zone and the fifth zone during the stoppage of the operation of the compressor is a predetermined timer. It is desirable not to do this until the elapsed time is measured. Further, a signal is output until the stopped state of the compressor is maintained for a certain period of time, and while the signal output is continued, the automatic switching of the cooling / heating based on the third and sixth zones is performed. It is desirable not to do it.

Hereinafter, an embodiment of an air conditioner control device according to the present invention will be described with reference to the accompanying drawings.

FIG. 2 shows an outline of the air conditioner. In the figure, the refrigeration cycle is configured 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 an annular manner with refrigerant piping. I have. When the four-way valve 2 is in the state of the solid line shown in the figure, the refrigerant discharged from the compressor 48 flows as indicated by the solid line arrow, condenses in the outdoor heat exchanger 3, and in the indoor heat exchanger 5. Evaporate to cool the room. In addition, four-way valve 2
However, when it is in the state of the dotted line shown in the figure, the refrigerant discharged from the compressor 48 flows as shown by the dotted line arrow, condenses in the indoor heat exchanger 5, and evaporates in the outdoor heat exchanger 3. Heat the room. Reference numerals 7 and 8 denote an outdoor blower and an indoor blower, which blow air to the outdoor heat exchanger 3 and the indoor heat exchanger 5, respectively.

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

The push-type switch 9 is a switch that outputs a signal for switching operation start / stop of the air conditioner every time the switch 9 is pressed. The changeover switch 10 is for cooling mode C,
Heating mode H, cooling / heating mode automatic switching C / H, ventilation mode F
Is a switch for switching between. This changeover switch 10 includes
Gray code switches are used. Room temperature setting device 11
Is a setting device for determining a desired set temperature. This setting device
11 uses a gray code switch, and each code corresponds to a set temperature of 18 to 28, respectively.

A microprocessor (hereinafter, referred to as a microcomputer) 12 stores a program based on a flowchart described later. Switch 9, changeover switch 10, room temperature setting device 11
Pressing and setting state of the output ports R ₁ and R ₃ of the microcomputer 12
Are scanned by input ports K ₁ , K ₂ , K ₄ , K ₃ , J ₁ , J ₂ , input by the microcomputer 12 and stored in correspondence with a specific address.

The temperature detector 13 changes its internal resistance according to the temperature, and is provided at a position where the temperature of the conditioned room can be detected. One end of the temperature detector 13 is connected to the input port A ₃ (analog input terminal) of the microcomputer, and the other end is connected to the constant voltage power supply V _ss . The microcomputer 12 includes, for each one period of the program, type the current corresponding input port A ₃ on the temperature of the conditioning chamber, a data value based on the current value, A / D
(Analog / Digital) converted and stored. At this time, the data value is input a plurality of times, the average value is stored as the temperature value of the conditioned room, and the temperature is controlled based on the stored value.

Although not shown, a wireless remote controller (hereinafter, referred to as a remote controller) is disposed at an arbitrary position in the conditioned room, and the remote controller is provided with the same temperature detector as described above. . The microcomputer 12
The temperature data is taken in from the temperature detector of this remote control,
This temperature data is stored in a temperature detector 13 in the indoor unit.
Can be used for temperature control instead of or along with the temperature data from.

Light-emitting elements 14 to 20 for room temperature display are 15 ° C, 17 ° C,
The light emitting element is provided at a position corresponding to the scale of 19 ° C., 21 ° C., 23 ° C., 25 ° C., and 27 ° C., and the light emitting element corresponding to the scale closest to the temperature value of the conditioned room is turned on. Light-emitting element for cold air display
Reference numeral 21 denotes a heating operation, in which the indoor heat exchanger 5 (first
It turns on when the temperature in the figure has dropped below a predetermined value. This temperature is input to the input port A _{4 of the} microcomputer 12 using the same method as that for inputting the temperature value of the conditioned room to the temperature detector 22.
Enter from.

The light-emitting elements 23, 24, and 25 are light-emitting elements for cooling / heating mode automatic switching, cooling mode, and heating mode display.
3, 24 and 25 are provided near the characters indicating the respective modes. These light emitting elements 23, 24, 25 light up according to the set value of the changeover switch 10. In addition, changeover switch
When 10 is set to the blow mode F, the light emitting element 24 for cooling mode display is turned on. Emitting element 14 to 21 and the light-emitting element 23 to 25, and an output port R ₀ to R ₄ of the microcomputer 12, by using the display port O ₀ ~ O _6, is turned on by a dynamic lighting. 26 to 29 are inversion circuits.

The relay 31 controls the energization of the indoor blower 8 (FIG. 1). The relay 31 has one end connected to an output port R ₁₂ of the microcomputer 12 through an inverting circuit 35, the other end DC24 [V]
Connected to the constant voltage circuit.

The serial signal circuit 37 is connected to the output port R ₈ of the microcomputer 12, receives the control data output from the output port R _8, and generates a signal for determining the frequency (target frequency) of the AC power supplied to the compressor 48. Serial transmission to the outdoor unit. That is, based on the room temperature and the set temperature, the amount of increase or decrease of the frequency is obtained by PID control (or by a difference between the room temperature and the set temperature and fuzzy inference using a change in the difference), and a new frequency signal is calculated.

The constant at the time of calculation of the new frequency signal is set so that the temperature difference between the room temperature and the set temperature is normally small, and at the start of the air-conditioning operation, the room temperature sufficiently overshoots the set temperature, and Are set so as to quickly reach the set temperature. This sufficient overshoot can also be obtained by correcting the set temperature. For example, during cooling operation, set temperature to 4
低 く 5 degrees lower and set the temperature to 6-8 during heating operation
What is necessary is just to correct high.

The oscillation circuit 38 includes a crystal oscillator, a resistor, and a capacitor.
1, given to OCS3.

The constant voltage circuit that outputs the low voltage V _ss , DC 24, V _ASS , and V _REF can use a normal power supply circuit, and a description thereof will be omitted. The above V _ASS and V _REF are the upper limit voltage and the 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 performing a reset process of the microcomputer 12 when the power is turned on. This signal is output when the output of the power supply circuit exceeds a certain voltage value when the power is turned on.
Any output is acceptable.

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

In the figure, an AC 100 V voltage supplied from a commercial power supply 41 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 280V DC is input to the three-phase bridge type inverter 46.

The inverter 46 generates a three-phase AC having an effective value of 100 V from the DC 280 V, and operates the 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 a supply current value from the commercial power supply 41 detected by the current transformer 50 to a microprocessor (hereinafter referred to as a 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 (S ₁ , S ₂ , S ₃ ).

(1) A> shutdown of S ₁ compression _{48 (2) S 1 ≧ A} > S 2 controls frequency reduction _{(3) S 2 ≧ A>} S 3 control frequency rising prohibited (4) S ₃ ≧ A normal operating compressor temperature The sensor 52 detects the temperature of the compressor 48 and notifies the microcomputer 51 of the temperature. Microcomputer 51, the compressor temperature (T) and set compressor temperature _{(S 4, S 5, S} 6) and on the basis of the magnitude relation is performed such as the following control operation for example.

(1) T> S ₄ Stop operation of compressor 48 (2) S ₄ ≧ T> S ₅ Decrease in control frequency (3) S ₅ ≧ T> S ₆ Control frequency increase prohibited (4) S ₆ ≧ T Normal operation Serial The signal circuit 53 receives control data from the indoor unit side serial signal circuit 53 shown in FIG.
Tell 51. In the normal operation, the microcomputer 51 starts / stops the compressor 48 and controls the control frequency according to the control data from the indoor unit.

Such operation control of the compressor 48 by the microcomputer 51 is performed by the switching signal amplifying unit 54 controlling the switching operation of the inverter 46 in response to a command from the microcomputer 51.

That is, the microcomputer 51 outputs an on / off signal of the transistor included in the inverter circuit 46 based on the PWM theory in accordance with the frequency signal transmitted from the indoor unit.

Relay contact 55 and photo triac 56 are microcomputer
Operates under 51 controls. When the relay contact 55 is turned on, the outdoor fan 57 operates, and when the phototriac 56 is turned on, the four-way switching valve 58 is switched.

FIG. 4 is a flowchart showing an operation of a main part in automatic switching of the cooling / heating mode of the microcomputer 12 of the indoor unit shown in FIG.

Referring to FIG. 1, the microcomputer 12 first performs a key scan and inputs the pressing and setting states of the operation switch 9, the changeover switch 10, and the room temperature setting device 11.
Here, the operation switch 9 is an operation state, a changeover switch.
10 is based on the premise that the air conditioner is in the state of automatic switching D / H. Further, temperature data is input from the temperature detector 13 or from the remote controller to determine the room temperature of the conditioned room (step 1).

Next, the determined room temperature is changed to zones A, B,
It is determined which of the zones C, C ', B' and A 'is to be entered (step 2). These zones room temperature t, when the set temperature and T _s, A zone _{t-T s> + 3 ℃} B zone _{+ 3 ℃> t-T s} > 1.5 ℃ C zone + 1.5 ℃> t-T _s> 0 ℃ C 'zone _{-1.5 ℃ <t-T s <} 0 ℃ B' zone _{-3 ℃ <t-T s <} -1.5 ℃ a ' zone is defined as t-T _s <-3 ℃ You.

As a result of the zone determination, when it is determined that the room temperature t is in the A or A 'zone, if the compressor 48 is in the operating state at that time, the cooling mode or the heating mode is performed in order to continue the current cooling operation or heating operation. The heating mode is set (step 3).

On the other hand, when the compressor 48 is stopped, the timer I measures three minutes from the time when the compressor 48 enters the zone A or A '(step 4). Then, A or A 'while entering the zone, if the 3 minutes has elapsed, set to the time the cooling mode if the A zone _{(t> T s + 3 ℃} ), A' zone (t <T _s - If the temperature is 3 ° C.), the heating mode is set (step 4). It should be noted that, even after entering the zone A or A ', switching of the cooling or heating mode is not performed until three minutes have elapsed. This is because, due to the structure of the compressor 48, it takes three minutes to restart the compressor 48.

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

On the other hand, when the compressor 48 is stopped, the timer I measures time for 3 minutes and the timer II measures time for 60 minutes (step 6).

Then, if 60 minutes have elapsed while in the B or B 'zone, then, in the B zone (T _s + 3 ° C.>t> T _s +
1.5 ° C), set to cooling mode, and B 'zone (T _s
If the _{-3 ℃ <t <T s -1.5} ℃) is set to heating mode (step 4,5).

After that, when moving to the zone A or A ', after 3 minutes including the period in the zone B or B', the cooling mode is set for the zone A and the heating mode is set for the zone A '. (Steps 4 and 5).

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

After performing the selection of cooling or heating mode in this manner, it calculates the control frequency of the compressor 48 based on the set temperature T _s and room temperature t in which the determined, and transmits it to the outdoor unit (Step 7) . In the outdoor unit, according to the transmitted control frequency, the inverter
The operation speed of the compressor 48 is controlled by 46. After transmitting the control frequency, timers I and II are reset (step 8).

As is clear from these descriptions, according to the present embodiment, as long as the operation of the compressor 48 is continued, the initially set cooling or heating mode is maintained, and the room temperature overshoots to the set temperature. If you enter the opposite zone,
The switching between the cooling and heating modes is not performed (step 3). Mode switching is allowed only when the compressor 48 is stopped.

In this case, the compressor is stopped for at least three minutes before the mode is newly set and the operation of the compressor is restarted (timer I). After 3 minutes, A, A '
A determination of mode switching in the zone is made. Also, B, B ′
The mode switching determination in the zone is performed after the operation stop state continues for 60 minutes (timer II).

[Effects of the Invention] As is apparent from the above description, according to the present invention, during operation of the compressor, the initially set cooling or heating mode is maintained and mode switching is not performed. Even if the room temperature is overshot, there is no danger that unnecessary mode switching will occur. In addition to the above, even when the compressor is stopped, cooling based on the second zone and the fifth zone is performed. Since the switching of heating / heating is not performed until the timer operating during the stop of the operation of the compressor measures a predetermined elapsed time, even if the room temperature overshoots, unnecessary mode switching occurs during that time. No signal is output until the stopped state of the compressor is maintained for the specified time, and while this signal output is continued,
Since the automatic switching of the cooling / heating based on the third and sixth zones is not performed, an effect such as unnecessary mode switching does not occur even if the room temperature overshoots during that period.

[Brief description of the drawings]

1 is a control circuit diagram of an indoor unit of an air conditioner using one embodiment of the present invention, FIG. 2 is a schematic diagram of the refrigeration cycle, FIG. 3 is a control circuit diagram of an outdoor unit, and FIG. FIG. 5 is a flowchart showing the operation of the main part of the microprocessor shown in FIG. 1, and FIG. 5 is a diagram showing a general state of room temperature control in an air conditioner having an automatic cooling / heating mode switching function. 11… Room temperature setting device, 12… Microprocessor, 13 ……
Temperature detector, 46 …… Inverter circuit, 48 …… Compressor, 51
…… Microprocessor, 54 …… Switching signal amplifier.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F24F 11/02

Claims (3)

(57) [Claims] 1. The frequency of AC power supplied from an inverter circuit to a compressor is increased or decreased so that a difference between a room temperature and a set temperature is reduced at normal times, and the room temperature is set at the set temperature when air conditioning is started. And a plurality of temperature zones are set based on the set temperature, and a predetermined calculation result is obtained when the room temperature is in a specific temperature zone among the plurality of temperature zones. In an air conditioner configured to perform automatic switching of cooling / heating based on the condition, a means for determining whether the compressor is operating and a means for determining when the room temperature is in a specific temperature zone include: Means for preventing switching between cooling and heating when the operation of the compressor is determined. 2. The plurality of temperature zones, 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 closest to the set temperature below the set temperature.
, A sixth zone furthest from the set temperature, and a fifth zone between the fourth zone and the sixth zone, wherein the room temperature falls within the second zone or the fifth zone. A timer for starting the time counting from the time when the room temperature is in the second zone or the fifth zone, and a first mode for switching between cooling and heating when the timer counts a predetermined time. A cooling / heating switching means, a means for determining whether or not the compressor is operating, a means for resetting the time measurement of the timer when the operation of the compressor is determined, The control device for an air conditioner according to claim 1, further comprising: second cooling / heating switching means for switching between cooling and heating when entering the zone (6). 3. A means for outputting a signal for a certain period of time from a time when the means for determining whether or not the compressor is operating determines that the compressor has stopped, and a means for outputting the signal while the signal is being output. Means for preventing re-operation of the second cooling /
3. The control device for an air conditioner according to claim 2, wherein the heating switching means switches between cooling and heating when the signal stops being output and the room temperature enters the third zone or the sixth zone. .