JPH043844A - Method of controlling air conditioner - Google Patents

Abstract

PURPOSE:To get air of high temperature within a short period of time by a method wherein a temperature of a compressor under a hot air operation mode is compared with a normal operating mode as a control for a thermal accumulation during a stopping operation and then a heater around the compressor and a motor coil are electrically energized to keep it at a high temperature. CONSTITUTION:Under a hot air operation mode, a heating calorie for a compressor 1 is increased and an amount of electrical energization for a heater 13 fixed around a compressor and a motor coil is increased. In addition, a degree of opening of an expansion valve 5 is set to a minimum value within a range of a degree of opening of control when energized and as its subsequent temperature is increased, it is increased in sequence. A degree of opening at this time is set such that an over-cooling of an indoor heat exchanger 3 is not initially taken much at the beginning of operation and when it is stabled, it is less than a limited temperature of the compressor 1 so as to keep a higher temperature than that of the normal heating operation. An amount of indoor air is set such that a fan 6 is operated at its minimum speed when a temperature of the indoor heat exchanger is less than its predetermined value and when it exceeds a predetermined value, it is changed over to the number of revolution gradually increased and at the same time an air blowing temperature is sensed by a thermistor 10 and when it reaches its target temperature, it is changed in sequence to its subsequent number of revolution.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method and device for controlling an air conditioner, and particularly to an air peace machine using a rotation speed controlled compressor.
The present invention relates to a control method for generating high-temperature air in a short time and suppressing increases in discharge pressure and discharge temperature in order to ensure reliability of a compressor.

[Conventional technology]

As a conventional compressor heat storage method, a method is described in JP-A-61-16278, in which a low voltage is applied to a motor at low temperatures to heat it.

In addition, as a conventional expansion valve control, Japanese Patent Application Laid-Open No. 64-7955
As described in No. 1, a control method is disclosed in which the opening degree of the expansion valve is made larger as the speed increases and conversely as the speed becomes lower, the opening degree is decreased in accordance with the compressor rotation speed.

In addition, as a control of indoor air volume, JP-A-61-17304
As described in No. 5, a method is disclosed in which the temperature of the indoor heat exchanger is set in stages, and the higher the temperature, the greater the air volume, and conversely, the lower the temperature, the smaller the air volume.

Furthermore, as a control of the compressor rotation speed,
As described in No. 869, a control method is disclosed in which, depending on the deviation between the current room temperature and the set temperature, the larger the deviation, the higher the compressor rotation speed, and conversely, the smaller the deviation, the lower the rotation speed of the compressor.

[Problem to be solved by the invention]

The conventional compressor heating method described above performs heating at low temperatures, and is a method to ensure reliability by preventing two-layer separation of oil and refrigerant and to optimize the refrigeration cycle in a short time.
This is enough to make the compressor temperature slightly higher than the outside air. In order to blow out high-temperature air in a short time, it is necessary to specially raise the compressor temperature to approximately the temperature during normal heating.

In addition, conventional expansion valve control technology is suitable for optimizing the refrigeration cycle because the opening degree corresponds to the compressor rotation speed. It is unsuitable for raising the temperature in a short time and obtaining high-temperature blown air quickly.

In addition, conventional indoor air volume control technology changes the indoor air volume according to the temperature of the indoor heat exchanger. Even if the temperature reaches a high temperature, the air volume will switch to the next level, so the temperature will not rise any higher. Furthermore, since the temperature of the heat exchanger is detected, it is difficult to accurately control the temperature of the blown air, such as in a refrigeration cycle where the inlet refrigerant is high in temperature and has a large superheated region, or conversely, in cases where the outlet refrigerant is low and highly subcooled.

Furthermore, conventional compressor control technology determines the rotation speed based on the deviation between the current room temperature and the set room temperature. The compressor is operated at high speed, resulting in high discharge pressure and compressor temperature, which may impair reliability.

The present invention was made in order to solve the problems of the prior art described above.It increases the discharge pressure and compressor temperature in a short time to obtain high-temperature air, and even under high load conditions, the discharge pressure exceeds the limit value. The purpose of this invention is to provide a method for controlling an air conditioner that also ensures reliability, such as prevention.

[Means to solve the problem]

In order to achieve the above objective, heat storage in the compressor when the air conditioner is stopped is carried out in high-temperature air operation mode by increasing the amount of heating compared to normal heating mode, and in order to keep the compressor at a high temperature, the compressor is The amount of heat expended to raise the temperature is greatly reduced, and the capacity pumped into the room can be increased in a short period of time.

Further, by increasing the rate of increase in the compressor rotational speed at the start of operation compared to during normal heating operation, predetermined discharge pressure and temperature can be obtained in a short time.

Further, the expansion valve opening degree is set to the minimum opening degree in the control opening degree range when the compressor is started, and the opening degree is increased as the temperature of the compressor increases after startup. In other words, the pressure and temperature are increased in a short period of time after the compressor is started, the indoor heat exchanger is heated to a high temperature, and high-temperature blown air is obtained in a short period of time. It also ensures reliability so that it does not exceed the limit.

In addition, the indoor air volume is maintained at a low air volume until the target temperature is detected by detecting the outlet air temperature, and the air volume is always switched after reaching a certain target temperature, so that the discharge pressure increases quickly and starts from a low air volume. Therefore, the bath air also approaches the heat exchanger temperature, allowing high-temperature air to be obtained in a short time and increasing the air volume while maintaining the same temperature.

In addition, the maximum command value for the compressor rotation speed is determined by detecting the outside air temperature, and by lowering the command value when the temperature is high, the pressure and temperature can be maintained even under conditions where compressor pressure and temperature rapidly increase under high load. can be used within limits.

[Effect]

The amount of heat applied to the compressor is increased by increasing the amount of current applied to the heater and motor coil installed around the compressor in the high-temperature air operation motor.

Further, the expansion valve opening degree is set to the minimum value of the control opening degree range at the time of startup, and gradually increases as the temperature rises thereafter. Generally, when the expansion valve opening degree is small, the refrigerant suction temperature of the compressor increases, and the discharge temperature and discharge pressure increase. Conversely, if the opening degree is large, the discharge temperature and discharge pressure will decrease. The opening degree at this time is set in accordance with the compressor temperature so that the indoor heat exchanger is not overcooled at the beginning of operation, and when stable, the temperature is kept below the compressor's limit temperature and higher than during normal heating operation. It's been done. If the compressor temperature drops for some reason, the control method returns the opening to the previous opening.

In addition, to control the indoor air volume, the fan rotation speed is operated at the lowest speed when the indoor heat exchanger temperature is below a predetermined value, and when it exceeds the predetermined value, it is switched to the next increased rotation speed, and at the same time, the blowing air temperature is detected and the target temperature is reached. When the rotation speed is reached, the rotation speed is sequentially changed to the next rotation speed. Here, the rotation speed of the fan is maintained for a certain period of time after the rotation speed is changed, and the time delay of the temperature detection thermistor is taken into consideration.

Furthermore, the maximum rotational speed of the compressor is determined by detecting the outside air temperature at the time of startup, and the compressor is operated at a rotational speed corresponding to that temperature. If the outside temperature fluctuates during operation, the rotation speed will change according to the temperature.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 1 to 7.

Fig. 1 is a refrigeration cycle control configuration diagram according to an embodiment of the present invention, Figs. 2 and 3 are flow charts and operation diagrams showing a method of controlling an expansion valve, and Figs. 4 and 5 are diagrams of an indoor fan control method. Flowchart and operation diagram showing the control method, Figures 6 and 7
The figures are a flowchart and an operation diagram showing changes in the rotation speed command of the compressor.

In Fig. 1, 1 is a compressor, 2 is a four-way valve that switches the refrigerant flow path for cooling and heating, 3 is an indoor heat exchanger, 4 is an outdoor heat exchanger, 5 is an electric expansion valve, and 6 is an indoor 7 is an outdoor fan; 8 is a thermistor that detects the compressor temperature;
9 is a thermistor for detecting the outdoor temperature; 10 is a thermistor for detecting the temperature of the indoor heat exchanger; 11 is a thermistor attached to the outlet formed by the casing 14 for detecting the temperature of the air blown from the indoor fan; 12 13 is an inverter that drives the compressor at a predetermined rotational speed and energizes the motor coil to raise the temperature of the compressor even when the compressor is stopped, and 13 is a heater that is closely attached around the compressor. Reference numeral 15 denotes an outdoor control circuit, which commands the compressor speed, takes in the compressor temperature and outside air temperature, and sets the opening degree of the expansion valve. 16 is a control circuit on the indoor side, which takes in the temperature of the heat exchanger and the temperature of the discharged air and sets the fan speed.

In FIG. 1, the equipment shown on the left side of the dashed line is installed in the outdoor unit, and the equipment shown on the right side is installed in the indoor unit.

In an air conditioner with such a refrigeration cycle configuration, when the high-temperature air operation mode is selected, the inverter energizes the compressor motor coil and heater to keep the compressor at a high temperature while the air conditioner is stopped. Prepare for the start.

Further, a method of controlling the electric expansion valve will be explained using the flowchart shown in FIG. 2 and the operation diagram shown in FIG. 3. The initial opening of the expansion valve is the minimum opening of 200 in the opening control range during high-temperature air operation.
Set to pulse. This opening is a value that suddenly increases the discharge pressure and temperature at startup when the compressor is operated at high speed, and also reduces the subcooling of the indoor heat exchanger and raises the heat exchanger temperature. The temperature is maintained until the temperature reaches 90°C. Next, the compressor temperature is measured at the same time as the compressor is started, and the opening degree is selected according to this temperature. The opening degree is divided into seven stages from 90°C to 121°C. In normal operation, the compressor temperature increases from the time of startup, so the opening degree gradually increases. In addition, if the temperature decreases over time, the opening degree will return to its original value. The relationship between the compressor temperature and the opening degree of the engraving valve used here is set so as not to exceed the limit temperature of the compressor at the time of startup and to maintain the temperature at a high temperature during the stable state.

The flowchart in Figure 4 regarding the indoor fan control method,
This will be explained using the operation diagram shown in FIG. The speed at the start of operation is set to the lowest speed of 370 m inl. Next, the temperature of the indoor heat exchanger is measured, and if the temperature exceeds 24°C, the fan speed is increased to the next step 75Qm i ril. The time it takes to increase the speed is generally called the preheating time to prevent direct exposure to cold air. Since the fan speed during preheating is low, the amount of heat dissipated into the room decreases, and the discharge pressure and temperature rise quickly. However, if this state is maintained,
As the pressure limit is exceeded, the inverter current also increases and the protection circuit works, causing the compressor speed to drop and its capacity to decrease, so the fan speed is increased after preheating is completed. When this time is released, the detected temperature is switched from the heat exchanger temperature to the blowing air temperature, and when the blowing temperature reaches 80'C, the fan speed is further increased by 50ml/h''.This speed increases the blowing temperature by 2 to 3 This is the amount of speed increase that suppresses the drop in temperature.Here, for 90 seconds after speed increase, the fan speed is maintained without temperature detection in consideration of the heat capacity of the detection thermistor, that is, the time constant.

As the fan speed increases, the discharge pressure decreases, the compressor speed increases accordingly, and when the blowout temperature reaches 80 again, the fan speed is further increased by 50 m 2 ]n' as in the previous step. Here, if the blowout temperature drops to 74°C, the fan speed will be reduced by 50 min.
The switching temperature of the fan speed was kept constant at 8 o'C, but -8 o'C
After the temperature exceeds 0'C, control such as sequentially lowering the target value may be applied. Further, when the hot air operation time ends, the fan speed switches to the normal heating set speed.

Next, a method for selecting the upper limit command value of the compressor rotation speed will be explained using the flowchart of FIG. 6 and the operation diagram of FIG. 7. The compressor speed at the start of operation is set to 8000 miri1.

This speed is the maximum speed when the load of the air conditioner is light when the outside temperature is 8℃ or less.If this speed is commanded even during overload operation when the outside temperature is high, the indoor temperature is also high, so the discharge pressure will exceed the limit value. I'll go beyond it. Therefore, the outside air temperature is detected at the same time as startup, and the compressor is driven at a speed corresponding to this temperature. Here, even if the outside temperature changes during operation, this method is applied to select the compressor speed. In addition, here, the change in speed is determined in steps with respect to the outside temperature, but it is also possible to set a hysteresis as the outside temperature rises or falls, or to determine the speed as a function of the outside temperature. . Like the fan speed, the compressor speed is also operated at the normal heating command speed when the high temperature air operation time ends.

〔Effect of the invention〕

Since the present invention is configured as described above, it produces the effects described below.

When the air conditioner is stopped, the heat stored in the compressor is larger than the amount of heating for normal heating, resulting in a high temperature.When high-temperature air operation starts, the amount of heat consumed to raise the compressor temperature can be reduced, and the rate of increase in rotation speed is also large. It takes less time to reach the specified pressure and temperature, and the amount of heat can be quickly sent indoors.

In addition, since the engraving valve opening is set small at the beginning of operation, the pressure and temperature of the compressor rise quickly, the temperature of the indoor heat exchanger rises, blowing out high-temperature air in a short time, and the compressor temperature continues to rise. Because it maintains a high temperature, it can stably discharge high-temperature air. Similarly, since the indoor fan speed is set to a low speed at the beginning of operation, the pressure of the compressor increases quickly, blowing out high-temperature air in a short time, and the speed is increased after the blowing temperature reaches a sufficiently high temperature, which improves the feeling of heating. do. Furthermore, since the compressor rotational speed at this time is set to a lower speed as the temperature increases in accordance with the outside air temperature, a sudden rise in pressure during high load can be suppressed, and reliability can be ensured without exceeding the limit pressure.

[Brief explanation of the drawing]

FIG. 1 is a refrigeration cycle control configuration diagram according to an embodiment of the present invention, FIGS. 2 and 3 are flow charts and operation diagrams for explaining the expansion pressure valve control method, and FIGS. 4 and 5 are FIG. 2 is a flowchart and an operation diagram for explaining a method of controlling an indoor fan. FIG. FIG. 6 and FIG. 7 are a flowchart and an operation diagram for explaining the speed command of the compressor. 1... Compressor, 3, 4... Heat exchanger, 5... Expansion valve. 6.7 Fan, 8.9.1o, 11...Thermistor,
13...Heater, 15.16...Control circuit. λth flash

Claims (1)

[Claims] 1. In an air conditioner having a high-temperature air operation function, which consists of a compressor, a heat exchanger, an expansion valve, an air blower, a thermistor for detecting the temperature of each part, etc., and is equipped with a high-temperature air operation switch, As heat storage control during stoppage, the compressor temperature is maintained at a higher temperature in the high-temperature air operation mode than in the normal heating mode by energizing the heater installed closely around the compressor and the motor coil. How to control an air conditioner. 2. Claim 1, characterized in that the rate of increase in the rotational speed of the compressor during high-temperature air operation is greater than during normal heating.
The method for controlling an air conditioner described in Section 1. 3. Set the target value of the compressor temperature during high-temperature air operation to a higher temperature than during normal heating operation, and the initial opening of the expansion valve starts from the minimum opening of the control opening range, and the compressor temperature after operation 3. The method of controlling an air conditioner according to claim 1, wherein the opening degree is selected to be large as the opening degree increases, and the opening degree is selected to be small as the opening degree is decreased. 4. After starting the compressor, the indoor fan operates at the lowest rotation speed when the indoor heat exchanger temperature is below a predetermined value, and when it is above the predetermined value, it operates at the next highest rotation speed, and furthermore, the blowing air temperature is set to a predetermined value. When the rotation speed reaches the next rotation speed, the rotation speed is maintained for a certain period of time, and then when the temperature of the blown air exceeds a predetermined value, the rotation speed is sequentially shifted to the high speed side and the high-temperature air operation ends. 4. The method of controlling an air conditioner according to claim 1, 2, or 3, wherein the rotation speed is then set to the rotation speed of normal heating operation. 5. Claims 1, 2, and 3, characterized in that the maximum rotational speed of the compressor is selected depending on the outside air temperature.
The method for controlling an air conditioner according to item 4.