JPH02263029A - Device for controlling year round air cooling in air conditioner - Google Patents

Abstract

PURPOSE:To prevent worsening of reliability of the compressor and electric accessories of an outdoor machine by a method wherein a load on the outdoor side is detected by means of a piping temperature, and by means of the detecting temperature, the compressor is stopped when the pressure on the high pressure side of a refrigerant in a freezing cycle is not increased and brought into a low state. CONSTITUTION:A temperature change as a partial pressure to a resistor Ra is inputted to a microcomputer 2 by a piping temperature thermistor 1a on the outdoor side, it is identified by a comparing device 3 in which region of a set temperature region piping temperature data is, an output signal is fed to control ports SH, H, M, L, and SL for the number of revolutions of an outdoor fan motor, a voltage applied to a fan motor 6 is varied through a number of revolutions varying circuit 4 and a switching source circuit 5 to vary the number of revolutions. A vaporizer temperature on the indoor side is prevented from lowering, failure in operation of a compressor is prevented from occurring due to compression of a refrigerant. When a piping temperature, i.e. a pressure on the high pressure side, is not restored even when the fan motor is stopped, when this state is continued for a specified time starting from a point of time when the fan motor is stopped, a stop signal is outputted from an outdoor fan stop time measuring means 7 to a compressor drive stop means 8 to stop a compressor 9.

Description

[Detailed description of the invention] Industrial applications The present invention relates to annual cooling of an air conditioner.

2. Description of the Related Art Conventionally, various proposals have been made regarding annual cooling of air conditioners. In particular, by varying the operating rate of the outdoor fan motor of an air conditioner, there are many cases in which the heat exchange capacity is reduced, the high-pressure side pressure is reduced, and the indoor evaporator is prevented from freezing. Furthermore, as shown in FIG. 6, the control for varying the operating rate of the outdoor fan motor involves inputting the voltage divided by the outdoor temperature thermistor IC to the microcomputer 2, and using the signal from the microcomputer 2 to control the relay coil 10. There is a method in which the current is set to 0N10FF and the induction motor is simply controlled ON10FF, and a control method in which the speed is reduced using a transistor motor.

Conventional technology only controls the heat exchanger capacity by varying the operating rate of the outdoor fan motor, and even if the compressor capacity is increased or decreased, it is always in continuous operation. It is. In addition, the only protective control against malfunctions in such a continuous operation state is operation stop control based on detection of freezing of the indoor evaporator.

Problems to be Solved by the Invention However, such conventional control has a number of problems.

First, depending on the indoor and outdoor load conditions, even if you reduce the compressor capacity to the minimum or stop the outdoor fan motor,
The indoor antifreeze control may not work and the compressor may continue to operate at minimum capacity. In such a state, even if the outdoor fan motor is stopped, the pressure on the high pressure side does not rise and the pressure on the low pressure side remains high, and the difference between high and low pressures becomes small.

If this happens, the circulation of refrigerant and oil in the refrigeration cycle will become poor, and the discharge temperature of the compressor will rise abnormally, as shown in FIG. This causes the reliability of the compressor to deteriorate, so it is necessary to protect it. Second, when the outdoor fan motor is stopped, there is no flow of air to the electrical components inside the outdoor unit. In particular, the heat dissipation and cooling effects of the power components installed in variable capacity air conditioners will be eliminated, which also poses issues in terms of reliability design and must be protected.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, it is an object of the present invention to realize protective control that prevents deterioration in reliability of an outdoor unit compressor and electrical components.

Means for Solving the Problems In order to solve the above problems, the present invention provides a variable capacity air conditioner in which a transistor motor is mounted on the outdoor unit, an outdoor pipe temperature detection means for detecting an outdoor load, and an outdoor pipe temperature detection means for detecting the outdoor load. A temperature comparison means for comparing the level of the piping temperature and a preset temperature, and a rotation speed variable means for increasing, decreasing or stopping the rotation speed of the transistor motor of the outdoor unit according to the height of the comparison means, The compressor is provided with a compressor stop means that stops the compressor when the stop time of the compressor exceeds a certain time.

Further, the present invention uses a high-pressure side pressure detection means of the outdoor unit to detect the outdoor load, and stops the compressor when the high-pressure side pressure decreases for a certain period of time or more.

Furthermore, the present invention uses an outside air temperature detection means to detect the outdoor load, and the compressor is stopped depending on the level of the temperature.

action The effects of the above means are as follows.

The present invention detects the outdoor load using a piping source, and stops the compressor when the high-pressure side pressure of the refrigerant in the refrigeration cycle does not increase and becomes low based on the detected temperature. Thereby, it is possible to prevent a situation in which the difference between high and low pressures is small, the circulation of refrigerant and oil becomes poor, and the compressor discharge temperature increases, leading to deterioration of reliability. In addition, even with the high heat generation components normally installed in variable capacity air conditioners, if the outdoor fan motor is decelerated or stopped and the compressor is left running for a long time, the airflow can be improved. It is also effective as a protection against this, since the heat dissipation effect becomes extremely poor.

Furthermore, by detecting the load of the refrigeration cycle using a refrigerant pressure switch, the present invention has good responsiveness to load fluctuations and can more appropriately detect the difference between high and low pressures. Direct load control is possible.

Furthermore, the present invention not only makes it possible to easily estimate the load condition of the compressor and protect it by using an outside temperature detection means for outdoor load detection, but also enables the estimation of the heat radiation efficiency by estimating the temperature rise of the heat generating components. By knowing the degree of necessity, it is possible to control the compressor operating time to the maximum extent when the outdoor fan motor is decelerated or stopped.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

First, a first embodiment of the present invention will be described with reference to FIG.

In the figure, reference numeral 1a denotes an outdoor pipe temperature thermistor, which inputs temperature changes to the micro combinator 2 as a divided voltage with respect to a resistor Ra. Piping temperature data is from comparison device 3.
This determines which region of the preset temperature range it is in, and provides an output signal to the control boat (SH, H, M, L, SL) that varies the rotation speed of the outdoor fan motor accordingly. As a result, the rotation speed variable circuit 4 outputs a control signal to the switching power supply circuit 5, varies the voltage applied to the fan motor 6, and changes the rotation speed (SH-3L
).

In this embodiment, as shown in FIG. 2, when the outside temperature drops and the pipe temperature drops below 30°C, the outdoor fan motor 6 is
It lowers the rotation speed to a lower level and keeps the pipe temperature always above a certain temperature. The piping temperature is almost equal to the condensation temperature of the refrigerant, and this control can prevent the temperature of the indoor evaporator from decreasing, and prevents frost formation on the evaporator and further decreases in the amount of heat exchange due to frost formation. Compressor failure due to refrigerant liquid compression can be prevented. However, if the outside air temperature drops further and the piping temperature, that is, the pressure on the high pressure side, does not recover even if the fan motor is stopped, refrigerant circulation will deteriorate, causing various problems in the refrigeration cycle, such as abnormally rising discharge temperatures. Problems will occur. In order to protect this, in this embodiment, from the time when the fan motor 6 is stopped, the outdoor fan stop time measuring means 7 determines that if the state continues for a certain period of time or more, the compressor drive stop means 8 will stop the fan motor 6. It outputs a signal to stop the compressor 9.

Next, a second embodiment of the present invention will be described with reference to FIGS. 1 and 3. Components that are the same as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 1, 1b is a pressure switch on the high pressure side of the outdoor unit. The H/L voltage is input to the microcomputer 2 by 0N10FF of the pressure switch 1b. By inputting this signal, the rotation speed control output of the outdoor fan motor is changed from the normal rotation speed (SH-3L) to a stopped state, and the rotation speed variable circuit 4 outputs a control signal to the switching power supply circuit 5, and the voltage is applied to the motor 6. Variable voltage and stops. Similarly to the first embodiment, the outdoor fan stop time measuring means 7
Accordingly, the fan stop time is measured, and if this state continues for a certain period of time or more, a stop signal is output to the compressor drive stop means 8, and the compressor 9 is stopped. In this example, the third
If the high pressure side pressure falls below the pressure point H shown in the figure, the outdoor fan motor is stopped, and the state in which the pressure falls below the H point is measured. Normally, when the pressure switch 1b operates and the outdoor fan stops, the high-pressure side pressure returns, the difference between high and low pressure increases, the circulation of the refrigerant becomes smoother, and the condensing temperature rises, exceeding the temperature at which cooling operation is possible. , and the pressure switch also returns to its normal state, which is repeated. However, in cases where the outside air temperature is abnormally low, no matter how much the outdoor fan motor is stopped, the pressure on the high pressure side will not recover and various problems as described above will occur, so protection is important. In addition, when compared with Example 1, as shown in Figure 5, the control using the pipe temperature is a little delayed from the actual condensing temperature, but in the case of a pressure switch, it is equal to the condensing temperature. , more responsiveness (becomes), and ideal control is possible.

Further, a third embodiment of the present invention will be described with reference to FIGS. 1 and 4. Components that are the same as those in the previous embodiment are given the same reference numerals and description thereof will be omitted.

In FIG. 1, IC is an outside air temperature thermistor, and temperature changes are input to the microcomputer 2 as a divided voltage across a resistor Re. The comparison device 3 determines which region of the preset temperature range the outside temperature data is in, and outputs an output signal to the control port (SH-3L) that changes or stops the rotation speed of the outdoor fan motor accordingly. give.

In this embodiment, as shown in Fig. 4, when the outside temperature drops below 20°C, the fan motor rotational speed is reduced to one rank lower in 5°C steps to maintain the refrigerant condensation temperature above a certain temperature. The time from when the outside air temperature reaches point T and the outdoor fan motor stops is measured by means 7 at outdoor fan stop time 81, and if this state continues for a certain period of time or more, A stop signal is output to the compressor drive stop means 8, and compression I! &9 is stopped.

In this example, we will use a simple method (estimate the load state of the compressor,
Not only can it be protected, but the necessary degree of heat dissipation efficiency can be determined by estimating the temperature rise of heat-generating parts, and the outdoor fan motor can be controlled to the maximum possible compressor operation time in deceleration and stop conditions. It is something to do.

Effects of the Invention As is clear from the embodiments described above, the present invention has the advantage that during annual cooling operation, when the piping temperature does not rise even after the outdoor fan motor stops, the refrigerant and oil circulation is poor and the compressor discharge is reduced. Pressure machines where the temperature rises abnormally (
This has the effect of protecting against deterioration in ffi reliability, and is a very effective protective control.

Further, since the means for determining whether the refrigerant is in a normal circulating state is performed by the outdoor unit high-pressure side pressure switch, it is possible to realize fast-responsive and detailed control at a value that is approximately the same as the refrigerant condensing temperature.

In addition, by using the outside temperature to determine the detection means, it is not only very easy to implement in terms of system design, but also by selecting the outside temperature and operating time to prevent reliability degradation due to temperature rises in electrical components. By doing this, you can control the problem to the maximum extent possible.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing an embodiment of the present invention, Fig. 2 is a characteristic diagram showing the first embodiment of the invention, Fig. 3 is a characteristic diagram showing the second embodiment of the invention, and Fig. 4 is a characteristic diagram showing the second embodiment of the invention. The figure is a characteristic diagram showing the third embodiment of the present invention, and FIG. FIG. 6 is a circuit diagram showing a conventional example, and FIG. 7 is a characteristic diagram showing a conventional example. 1a...Piping temperature thermistor, 1b...
・Pressure switch, IC...Outside temperature thermistor, 2...Microcomputer, 6...
・Transistor motor, 10...Relay coil, 11...Induction motor. θ lQ m Outside air marsh 1

Claims (3)

[Claims] (1) A transistor motor is mounted on the outdoor unit, an outdoor piping temperature detection means as an outdoor load detection means, a temperature comparison means for comparing the detected piping temperature with a preset temperature, and and a rotation speed variable means for increasing, decreasing or stopping the rotation speed of the transistor motor of the outdoor unit depending on the height of the comparison means, and a compressor stop means for stopping the compressor when the stop time of the transistor motor exceeds a certain time. Annual cooling control device for air conditioners equipped with (2) The air conditioner according to claim (1), wherein the outdoor unit's high-pressure side pressure detecting means is used as the outdoor load detecting means, and the compressor is stopped when the high-pressure side pressure decreases for more than a certain period of time. Cooling control device. (3) The annual cooling control device for an air conditioner according to claim (1), wherein outside air temperature detection means is used as the outdoor load detection means.