JPH01300149A - Control device for air conditioner - Google Patents

Abstract

PURPOSE:To prevent useless energization of a crank case heater by a method wherein the crank case heater is turned OFF during an operation of a compressor and then ON/OFF control for the crank case heater is carried out in response to a difference in temperature of a compressor temperature and the surrounding atmosphere temperature during a stoppage of the compressor. CONSTITUTION:A present operating condition is judged and if the operation is being carried out, an OFF signal is outputted to a control relay 17 for a crank case heater 8 through an output circuit 11 and a buffer 20. If the operation is stopped, a tempera ture data T1 of a compressor got through a thermistor 21 for use in sensing a tempera ture of the compressor and a resistor 23 for dividing a voltage is inputted through an input circuit 10 for a micro-computer 9. Then, a data T2 of surrounding air tempera ture got by the thermistor 22 for use in sensing the surrounding air temperature and the resistor 23 for dividing a voltage is inputted, a different in temperature T is calculated and then it is compared with a predetermined difference in temperature T3. In case of T3>= T, an ON signal is outputted to a controlling relay 17. In case of T3< T, it is compared with a predetermined difference in temperature T4 higher than T3 and in turn in case of T4< T, an OFF signal is outputted to the control relay 17.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control device for an air conditioner, and particularly to a control device for an air conditioner having a crankcase heater.

(Prior art) Figs.
FIG. 2 is an electrical circuit diagram showing a conventional air conditioner control device shown in No. In the figure, 1 is a three-phase AC power source, 2 is a compressor, this device uses an electric compressor, and 3 is a contactor for energizing the compressor 2, which has a make contact 3a. 4b is a break contact of a protection device that operates when an abnormality occurs in the air conditioner, and becomes open when an abnormality occurs. Reference numeral 6 represents an input terminal to which an operation command signal for the air conditioner is manually input, and reference numeral 8 represents a crankcase heater of the compressor 2. Reference numeral 9 denotes a microcomputer (hereinafter referred to as a control means) as a control means that continuously energizes the crankcase heater 8 when the main power source (not shown) is turned on, and when the compressor 2 is driven, performs intermittent operation after the compressor has stopped. (referred to as a microcomputer), the input circuit 10. Output circuit 11. It is composed of a CPU (central processing unit) 12 and a memory 13, and has a timer for energizing the crankcase heater 8 intermittently in an ON10FF pattern for a predetermined period of time.

14 is a photocoupler that manually inputs the operation command signal from the input terminal 6 to the microcomputer 9; 15 is a relay for detecting an abnormality that is deenergized according to the operation of the protective device (the state of the contact 4b); 15b
is its break contact, 16 is the drive relay for contactor 3,
16a is its make contact, 17 is a relay for controlling the crankcase Peter 8, 17a is its make contact, 18 is a current control resistor, 19 is a pull-up resistor, and 20 is an output buffer.

Next, the operation will be explained according to the flowchart shown in FIG. The program of this flowchart is stored in the memory 13 of the microcomputer 9 and executed by the CPU 12.

When the program is started, first, in step 30, the microcomputer 9 outputs an ON signal for the control relay 17 of the crankcase heater 8 from the output circuit 11 via the buffer 20. This closes the make contact 17a of the relay 17.
The crankcase heater 8 connected in series with the make contact 17a between the lines of the three-phase AC power supply 1 is turned on. Next, the microcomputer 9 processes in the CPU 12 the operation command No. conduct. If the command signal is not a driving start condition, steps 30 and 31 are looped.

If the conditions for starting operation are met, the crankcase heater 8 is turned off in step 32, and an ON signal for the drive relay 16 of the contactor 3 is outputted in step 33. This closes the contact 16a, the contactor 3 is driven, the contact 3a closes, and the compressor 2
operates and the air conditioner becomes operational. Once the operation starts, steps 30, 31, and 32 described above are performed.
Never branch to. Next, in step 34, the current operating state is determined, and if the operation is in progress, in step 35, the control relay 17 of the crankcase heater 8 is set to 0FFL,
In step 36, a control flag FT for a timer that counts a predetermined period of time is reset (to "0").

Here, if the compressor 2 is in operation, the crankcase heater 8 is always in an OFF state. Also, step 3
If the operation stop command signal is input manually in step 3, an OFF signal for the drive relay 16 of the contactor 3 is output. Now contact 16
a is opened, the contactor 3 is no longer excited, and the contact 3
a opens and the compressor 2 stops. When the compressor 2 comes to a halt, the process proceeds to step 37, where it is determined whether or not the timer control flag FT is "0". If it is "0", the timer control flag FT is set ("1") at step 38. )
Then clear and start the timer in step 39,
Make it count for a predetermined time. Timer control flag is “0”
Otherwise, the timer is counting the specified time, so
The processing in steps 38 and 39 is not performed. Next, in step 40, it is determined whether the timer has completed counting the predetermined time, and if not, step 33.3.
4,37. \40 is looped to hold the current output (energized/stopped) of crankcase Peter 8. When the predetermined time count ends, the current state of the crankcase heater 8 is determined in step 41, and the output state is reversed in steps 42 and 43. That is, if the crankcase heater 8 is OFF, the process proceeds to step 42, where the crankcase heater 8 is turned ON, and the crankcase heater 8 is turned ON+.

If so, proceed to step 43 and turn off the crankcase heater 8. Then, in step 44, the timer control flag FT is reset, and the timer is again controlled to count a predetermined period of time.

FIG. 6 shows the compressor 2 and crankcase heater 8 described above.
3 is an operation time chart showing the operating state of the controller. Point A is when the hand switch is ON and compressor 2 is OFF.
F, crankcase heater 8 is turned on. At point B, the crankcase heater 8 is turned off when the compressor 2 starts operating. Point C is when the compressor 2 stops, and from this point on, the timer sets the predetermined time (
1) counting is started. And point 1-D,
E and F are the points at which the predetermined time (1) has finished counting, and the state of the crankcase heater 8 (
energization/stopping) is reversed. Further, at point G, when the compressor 2 starts operating again, when the compressor 2 is turned on, the crankcase heater 8 is turned off regardless of the current state.

[Problem to be solved by the invention]

A conventional control device for an air conditioner with a crankcase heater is configured as described above, and when the compressor is stopped, the crankcase heater is energized at a predetermined value U, νijf (t
) duty control to save energy, but when the outside temperature is high and the air conditioner is being cooled, the energization time is longer than necessary.
Power consumption is wasted. Additionally, during heating when the outside temperature is low, there is not enough time for the electricity to be turned on, making it easy for refrigerant to dissolve into the refrigerating machine oil in the compressor, causing a large amount of refrigerating machine oil to leak out when the compressor is started, causing insufficient slippage of the compressor. There were problems such as:

This invention was made to solve the above-mentioned problems, and its purpose is to obtain a highly reliable air conditioner control device without unnecessary energization of the rank case heater. .

[Means to solve the problem]

Therefore, the air conditioner control device according to the present invention turns off the crankcase heater when the compressor is in operation, and controls the energization of the crankcase heater based on the temperature difference between the outside air temperature and the compressor temperature when the compressor is stopped. This is how it was done.

[Effect]

The IIJ control device for an air conditioner according to the present invention is comprised of an outside air temperature detection means and a compressor temperature detection means, and controls the energization of the crankcase heater based on the temperature difference between the temperature data obtained from these temperature detection means.

(Example) An embodiment of the present invention will be described below based on the drawings.

FIGS. 1(a) and 1(b) are electrical circuit diagrams showing an embodiment of the present invention, which has the same structure as the conventional one. However, the input circuit 10 of the microcomputer 9 is connected to a compressor temperature detection thermistor 21 which is a compressor temperature detection means, and an outside air temperature detection thermistor 22 and a voltage dividing resistor 23 which are outside air temperature detection means. . Furthermore, a program according to an embodiment of the present invention is stored in advance in the memory 24 of the microcomputer 9.

Next, the operation will be explained according to the flowchart shown in FIG. The program of this flowchart is
It is stored in the memory 24 of the computer and executed by the CPU 12. When the program starts, first
In step 50, a driving command is manually input from the input terminal 6 through which the driving command signal is input via the photocoupler 14 and the input circuit 1o of the microcomputer 9. In step 51, the drive relay 16 of the contactor 3 is
The 0N10FF signal is outputted via the output circuit 11 and the buffer 20. Next, in step 52, the current operating state is determined, and if the operation is in progress, the process proceeds to step 59, where the output circuit 11 is connected to the control relay 17 of the crankcase Peter 8.
゜Outputs an OFF signal via the buffer 20. If the operation is stopped in step 52, the process advances to step 53, and the compressor temperature data T1 obtained by the compressor temperature detection thermistor 21 and the partial pressure resistor 23 is input to the input circuit 1 of the microcomputer 9.
Manpower through 0. Next, in step 54, the outside air temperature data T2 obtained by the outside air temperature detection thermistor 22 and the voltage dividing resistor 23 is inputted via the input circuit IO of the microcomputer 9. In step 55, the temperature difference ΔT between the compressor temperature T1 and the outside air temperature T2 obtained in steps 53 and 54 is calculated. Next, in step 56, the temperature difference ΔT between the compressor temperature T1 and the outside air temperature T2 is set to a predetermined value temperature difference T.
Compare with 3.

If the number is 1326, the process advances to step 57, and the output circuit 11. An ON signal is output via the output buffer 20. Due to the stiffness, the make contact 17a of the relay 17 closes, and the crankcase heater 8, which is connected in series with the make contact 17a, is turned on between the three-phase AC type [1 lines]. 73 at step 56
If <ΔT, the process proceeds to step 58, where the temperature difference ΔT is compared with a predetermined value temperature difference 'T4 which is larger than the predetermined value temperature difference T3. If T4<ΔT, the process proceeds to step 59, and the output circuit 11.
An OFF signal is output via the buffer 2o. If T4≧ΔT in step 58, the process branches to step 50.

FIG. 3 is an operation time chart showing fluctuations in the temperature difference ΔT between the compressor temperature T1 and the outside air temperature T2 and the operating states of the compressor 2 and crankcase heater 8. FIG. While the compressor is operating, the crankcase beater 8 is turned off regardless of whether the temperature difference ΔT is large or small. Compressor is stopped (0
), the relationship between the temperature difference ΔT and the predetermined temperature difference T3 is T3
When ≧ΔT (0), the crankcase heater 8 is turned on.
Therefore, the relationship between the temperature difference ΔT and the predetermined temperature difference T4 is 74<Δ
When the temperature reaches T (b), the crankcase heater 8 is turned off.

(Effects of the Invention) As described above, according to the present invention, the crankcase heater is set to 0FFL/0 while the compressor is in operation, and the compressor temperature is set to 0 FFL/during the compressor is stopped. Since the crankcase heater is controlled in a 0N10FF mode, not only is it possible to save energy by not energizing the crankcase heater more than necessary in the summer when the outside temperature is high, but also in the winter when the outside temperature is low. There is an effect that an apparatus can be obtained in which there is no shortage of power supply time for the crankcase heater, and the reliability at the time of starting the compressor is improved.

[Brief explanation of the drawing]

1(a) and 1(b) are electrical circuit diagrams showing one embodiment of the present invention, FIG. 2 is a flowchart showing its operation, and FIG.
The figure is an operation time chart showing temperature difference fluctuations between the compressor and outside air and the 0N10FF state of the compressor and crankcase heater. Figures 4 (a) and (b) are electric circuits showing a conventional air conditioner control device. 5 is a flowchart showing the operation, and FIG. 6 is an operation time chart of the compressor and crankcase heater shown in FIG. 4. 1.---Three-phase alternating current 2----1 Compressor 8---Crankcase heater 21---Compressor temperature detection thermistor 22---
---Thermistor for detecting outside air temperature In each figure, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] A control device for an air conditioner having a crankcase heater of a compressor, comprising an outside temperature detection means and a compressor temperature detection means, and controls energization of the crankcase heater based on a temperature difference in temperature data obtained by these temperature detection means. An air conditioner control device characterized by performing the following.