JPS5956033A - Capacity controlling method of air conditioner - Google Patents

Abstract

PURPOSE:To avoid uncomfortableness caused by excessive lowering of the room temperature, by operating an air conditioner at a capacity one stage higher than the actual capacity at the time when the temperature of air discharged from the air conditioner is higher than a first set value, and operating the air conditioner at a capacity one stage lower than the actual capacity at the time when the temperature of air discharged from the air conditioner is lower than a second set value. CONSTITUTION:The temperature of air discharged from an air conditioner is detected at the interval of two minutes. When the temperature of air discharged from the air conditioner becomes lower than about 17 deg.C at a time t3, the air conditioner is operated at the frequency of about 30Hz by lowering the frequency of operation about 15Hz by way of frequency control based on the temperature. By this 30Hz operation, the room temperature is kept stable between the temperature of Ts+1 deg.C and Ts+2 deg.C. On the other hand, when the temperature of air discharged from the air conditioner becomes higher than 19 deg.C, the air conditioner is operated at the frequency of about 40Hz by raising the frequency of operation about 15Hz. Thereafter, stable operation at the frequency of 30Hz and operation at the frequency of 45Hz for lowering the temperature of air discharged from the air conditioner are repeated alternately. With such an arrangement, it is enabled to protect the user from over-cooling due to excessive lowering of the temperature of air discharged from the air conditioner in case that the room temperature is set at a lower value.

Description

[Detailed description of the invention] It is something.

Conventional configuration and its problems Conventionally, in air conditioners using variable capacity compressors,
Temperature control during cooling operation detects the room temperature, sets the capacity based on the difference between the room temperature and the room temperature set value as shown in Figure 1, and changes the compressor capacity as the room temperature approaches the room temperature set value. was used to control the cooling capacity.

In other words, in a compressor whose capacity is varied by changing the rotational speed of the compressor, if the difference between the room temperature and the room temperature set value is 13°C or more, it will initially operate at the rotational speed F4, and when the room temperature decreases and reaches 13°C, it will shift to the first stage. It operates at the lower rotation speed F3, and when the room temperature further decreases and reaches 12℃, the rotation speed F2 is one step lower.
drive with

When the room temperature further decreases and reaches tl°C, operation is performed at the lowest rotational speed F1. The range of each rotational speed is different depending on whether the room temperature is rising or falling, and in the case of rising, the rotational speed is set to be the same until the room temperature is one step higher.

If the room temperature further decreases even at the lowest rotation speed F1, the compressor is stopped at the set temperature, and when the room temperature rises to 12° C., the compressor is operated again at the rotation speed F2.

When the above-described control is performed, the compressor is set to operate almost continuously at the rotation speed F1 without stopping.

In this case, the compressor performs cooling operation that matches the load, resulting in stable continuous operation for a long period of time, with almost no stoppages. Therefore, the blowing temperature is stabilized at the same blowing temperature and continues for a long time.

In such operations, when the desired room temperature is low, the air outlet temperature also decreases and continues for a long time, so in a space where the wind directly hits the human body, it becomes chilly and too cold, making it difficult to maintain comfortable air conditioning conditions for the entire living space. It had the disadvantage that it could not be done.

OBJECTS OF THE INVENTION The object of the present invention is to control the capacity of a compressor in order to prevent discomfort due to a decrease in the blowout temperature.

In order to achieve the object [] with the structure of the invention, the present invention provides a set temperature for the blow-out temperature such that a first set value T > a second set value T2, and when the room temperature falls within the set temperature range, the temperature is constant. The air outlet temperature is detected every hour, and the air outlet temperature is set to the first set value T1.
In this case, the engine is operated at a capacity one level higher than the current operating capacity, and when the outlet temperature is below the second set value T2, the engine is operated at a capacity one level lower than the current operating capacity.

By this control, the air outlet temperature is set to the first set value T1.
and the second set value T2 to prevent discomfort caused by a drop in the blowout temperature.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 2 to 6 of the accompanying drawings. In this embodiment, the capacity of the compressor is changed by changing the power frequency lc supplied to the compressor.
FIG. 2 shows the distribution of the power supply frequency based on the difference between the room temperature and the set temperature.

In the same figure, Ts ℃ is the room temperature setting value set by the thermostat, boundary lines are set at +1℃, +2℃, +3℃, and +4℃.
8 45H2KL if it falls below +2℃.

When the temperature drops below T8 +1°C, the frequency is increased to 30Hz, and when the temperature decreases further and falls below T8°C, the compressor is stopped.

When the compressor is stopped and restarted, it starts operating at 60Hz when Ts +2° is exceeded. Furthermore, when the room temperature rises during operation at each frequency, in the case of 3° Hz, it is set to 45 Hz when it exceeds Ts + 2°C, and in the case of 45 Hz, it is set to 60 Hz when it exceeds T8,3°C.

Figure 3 shows the range in which the temperature of the air outlet is controlled.

In the same figure, the blowout temperature control is performed as the room temperature decreases to T.
It enters when the temperature drops below 8+2℃, and the room temperature is 18℃ and Ts+
If it is between 4 degrees Celsius (shaded area), it is within the range for which blowout temperature control is performed.

FIG. 4 shows frequency allocation when controlling the temperature of the air outlet.

In the same figure, when the blowout temperature is between 17°C and 19°C, the current operating frequency is maintained, and when the blowout temperature is 19°C or higher, the frequency is increased by 1 sHz and the frequency is increased to 17°C.
When the temperature is below ℃, lower the 16H2 frequency. At this time, if the frequency is already the lowest frequency, the operation continues as is. When the blowout temperature further decreases to 16℃ or less,
The compressor is set to stop.

FIG. 5 shows a control block diagram of this embodiment.

In the figure, 1 is a thermistor that detects room temperature, 2 is A
/D converter, 3 is a thermistor for detecting the blowing temperature, 4 is an A/D converter, 6 is a CPU, 6 is a programmable counter, 9 is an inverter, and 10 is a compressor motor.

Next, its operation will be explained.

In the figure, room temperature is detected as a resistance value by a thermistor 1, and sent to cptres as digital data by an A/D converter 2. On the other hand, the temperature of the air outlet is detected as a resistance value by the thermistor 3, and sent to the CPtJ5 as digital data by the A/D converter 4. In the CPTJ5, the digital data sent from the A/D converter 2 and the digital data sent from the A/D converter 4 are compared with the frequency allocation shown in Figs. 2, 3, and 4, and the programmable Sends an address signal of the operating frequency to the counter 6.

The programmable counter 6 divides the reference frequency signal output from the oscillator 7 according to the address signal output from the CPU 5 and outputs an operating signal to the inverter control unit 8. The inverter control section outputs a waveform control signal for the inverter 9 based on the operating frequency from the programmable counter 6. The input AC power supply 9 once converts the AC power input into DC power, and sends the DC power to the compressor motor 10 as AC power at the operating frequency according to a control signal from the AC power controller 8 to operate the compressor.

Next, the control method of this embodiment will be explained with reference to the timing diagram of FIG.

In the figure, operation is restarted at time t0, and if the room temperature at that time is T8+2° or more, 60 Hz operation is performed with frequency allocation according to the room temperature shown in FIG.

As a result, the blowing temperature gradually decreases from around room temperature. Then, at time t1, the room temperature reaches Ts+2℃ and the frequency is 45Hz.
At the same time as starting operation, the frequency control is switched to "frequency control based on the room temperature" and frequency control is based on the "stiffness blowout heater" for a fixed period of time (2
The blowout temperature thermistor 3 starts detecting the blowout temperature every minute).In this case, the blowout temperature is 17℃.
Since the temperature is between 19°C and 19°C, operation continues at the same frequency of 45Hz.

Then, the air outlet temperature is detected every 2 minutes, and when the air outlet temperature becomes 17°C or lower at time t3, the operating frequency is lowered by 15 Hz by the air outlet temperature frequency correction shown in Fig. 4.
0Hz operation.

Due to this 30Hz operation, the room temperature is Ts+1℃ and Ts1,22
Stable between ℃ and ℃. And the blowout temperature is at time t6
If the temperature exceeds 19℃, increase the operating frequency by 15Hz to 40℃.
'Hz operation. After that, stable operation at 30 Hz was repeated, and then operation was repeated at 45 Hz to lower the blowout temperature.

If conventional blowout temperature control is not performed, t in Figure 6
After 2, as shown by the dotted line, when the blowing temperature is 17℃ or less, 4
Stable operation for a long time at 5Hz.

As explained above, in this embodiment, by controlling the blowout temperature, it is possible to avoid operating for a long time in a state where the blowout temperature is low, and also to extend the operation at the lowest frequency, thereby achieving an energy saving effect due to low input operation.

In addition, in this example, a method using frequency change by an inverter to vary the capacity of the compressor was explained, but other methods such as a method that changes the operating speed by changing the number of poles, a method that changes the cylinder volume, or a method that performs bypass. A similar effect can be obtained by changing the amount of refrigerant circulation.

Effects of the Invention As is clear from the above embodiments, the present invention includes a variable capacity compressor, a means for detecting room temperature, and a means for detecting outlet temperature, and when the room temperature is within the set temperature range, The blowout temperature is detected at regular intervals, and when the blowout temperature is above the first set value T1, the capacity of the compressor is increased by at least one step, and when the blowout temperature has decreased and is below the second set value T2, the compressor capacity is increased. The temperature of the air outlet is lowered by at least one level to the first set value T1 and the second set value T2.
This system prevents the blowout temperature from falling too low when the room temperature setting is set low, which would cause chills to the human body. By lowering the capacity by one level, cooling operation can be performed without spoiling the user's feeling.
It has excellent effects such as energy saving.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the allocation of compressor operating speed according to room temperature in a conventional control method, Fig. 2 is an allocation diagram of compressor operating frequency according to room temperature in a capacity control method according to an embodiment of the present invention, and Fig. 3 is a room temperature range diagram for controlling the outlet temperature in the same capacity control method, FIG. 4 is a frequency correction diagram of the outlet temperature in the same capacity control method, and FIG. 6 is a control block diagram for carrying out the same capacity control method. is a timing diagram of an example of operation in the same capability control method. 1.3...Temperature sensor, 5...CPU
, s... Inverter, 10... Compressor motor.

Claims (3)

[Claims] (1) It has a variable capacity compressor, a means for detecting the room temperature, and a means for detecting the blowout temperature, and when the room temperature is within the set temperature range during cooling operation, the capacity of the compressor is controlled by the blowout temperature. How to control the capacity of an air conditioner. (2) The number of variable capacity stages of the compressor is set to at least 3 stages, and the blowout temperature is set to the first set value T1>second set value T
2, the air outlet temperature is detected at regular intervals, and when the detected air outlet temperature is greater than or equal to the first set value T1, the compressor is operated with the capacity increased by at least one step. 2. The method for controlling the capacity of an air conditioner according to claim 1, wherein the capacity of the compressor is controlled to be lowered by at least one stage when the capacity is lower than the set value T2. (3) Second set value T2>Third fictitious value 1 for blowout temperature
3. A capacity control method for an air conditioner according to claim 2, wherein a set temperature T3 is set and the compressor is stopped when the blowout temperature detected at regular intervals is equal to or lower than the third set value T3.