JPS5942210B2 - air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air conditioner that controls the operation of a compressor in a refrigeration circuit by comparing detected room temperature with a predetermined reference value.
To prevent unstable operation due to incorrect room temperature measurement results due to power supply voltage fluctuations caused by the FF, turn on the kelp mixer and tusa.
Alternatively, malfunctions are prevented by providing a prohibition time for switching the compressor from ON to OFF for a certain period of time after the compressor is turned OFF.

A capacitor is generally connected in parallel to a thermistor that measures room temperature to prevent noise from entering.

This parallel circuit forms a bridge with a resistor providing a reference potential, and a comparator detects the unbalance of the bridge to measure the room temperature range, and the compressor operation control switch is opened or closed depending on this room temperature range.

However, in this method, large f? -, MI point is that when the compressor is turned on, the inrush current is particularly large, so the power supply voltage fluctuates greatly and the reference potential of the bridge changes.

On the other hand, the potential on the thermistor side does not fluctuate much because there is a capacitor in parallel.

Therefore, the output of the comparison detector is reversed, and the room temperature measurement results just before the compressor is turned on and the room temperature measurement results after the compressor is turned on are significantly incorrect. A phenomenon of putting away occurs.

In this way, when the compressor is turned on and off based on the room temperature measurement result, malfunctions such as repeated ON/OFF cycles of the compressor are likely to occur due to fluctuations in the power supply voltage.

The present invention eliminates the drawbacks of the prior art.

As a configuration for this purpose, the present invention provides a room temperature detection section having a capacitor connected in parallel to a thermistor, and a comparison detector that compares the output voltage of the room temperature detection section with a room temperature setting value, and controls whether the compressor is turned on or off. A controller is provided for controlling the compressor, and the controller is configured to control whether the compressor is ON or OFF.
A prohibition timer section is provided that outputs a signal until a certain period of time has elapsed from the time when A logic section that does not control ON or OFF is provided.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of a control circuit section of an air conditioner using the present invention.

In FIG. 1, current is supplied from an AC commercial power source 1 via a main switch S1 to a control circuit power transformer TR and a compressor 2 (the compressor 2 is supplied via a contact RYIA of a switching relay RYI). .

Control circuit power supply is diode bridge 3, constant voltage circuit TR
1 to form a positive power supply vO.

MC is a microcomputer.

The compressor opening/closing relay RYI is operated from the output EO of the microcomputer MC via the driver TR2.

Room temperature measurement is taken as a resistance change of a thermistor RT installed in the room, and a resistor RO connected to the output terminal DO of the microcomputer MC is connected to the bridge side BC in parallel with the resistor R1.

The output terminal DO has an open drain structure, and the resistor RO is connected in parallel to R1 only when the output terminal DO is turned on.

Since a constant resistor R2 is connected to the series bridge side BD, if the output terminal DO of the microcomputer MC is turned ON and OFF according to a predetermined sequence, the voltage of the reference potential V1 (point B) is changed according to the predetermined sequence. It can be changed.

In addition, the other bridge side EG includes a resistor R3, a temperature setting volume VR, the thermistor RT, and its series resistor R.
4, and the F point potential V2 is the thermistor RT.
It changes according to the change in resistance.

Further, the comparison detector IC1 compares the reference potential v1 and the F point potential v2, and when V2>Vl, the output v3 becomes a high output and is inputted to the input terminal A1 of the microcomputer MC.

C1 is a noise removal capacitor connected between both inputs of the comparison detector, and is usually about 0.01 μF.

Also, a capacitor C2 connected in parallel with the thermistor RT
is also used for noise removal, and is usually 10μF.
A certain degree is used.

Now, when the output terminal DO is ON, the potential V1 at the reference point B becomes high.

At this time, if the output v3 of the comparison detector is high, V2
>Vl, the resistance of the thermistor RT is high, and therefore the room temperature is lower than the temperature determined by the reference potential v1 at this time.

Conversely, if the output v3 is a low output, v2<Vl, which means that the room temperature is high.

Now, when the room temperature is such that the output v3 becomes high output when the output terminal DO is ON, turn off the compressor 2, and turn the compressor 2 at a room temperature such that the output v3 becomes input/output when the output terminal DO is OFF. Select each resistor so that when it is turned on, the temperature will be such that air conditioning can be performed well, and turn each resistor ON.
Let it be F point and ON point.

Compressor 2 turns ON when the room temperature is lower than the above reference temperature.
Set up the MC program sequence so that it becomes F and turns ON when it is high.

Figure 2 depicts these time sequences.

Now, at time TO, the reference potential v1 indicates the OFF point, and since the F point potential v2 is lower than that, the output v3 is a low output, so the room temperature is above OFFFF.

When the reference potential v1 indicates the ON point at point A in FIG. 2, the output v3 remains low, so the room temperature is above the ONN point.

At this point, the microcomputer MC is compressor 2.
An ON signal is output from output EO, relay RY1 is closed, and contact RYIA is closed.

However, because the inrush current of compressor C is large, the power supply voltage drops rapidly.

Normally the voltage of 100V drops to about 65V.

Therefore, the voltage vO of the control circuit also drops rapidly as shown in FIG. 2a (Fig. 2).

Therefore, the reference potential v1 also drops rapidly.

However, the potential v2 on the thermistor RT side is
It is kept almost constant by the action of 2.

Therefore, in the range of Hart in FIG. 2, both the OFF point and the ON point are below the potential v2, and the room temperature measurement results show that the room temperature is lower than the OFF point.

Therefore, if the compressor 2 is turned OFF based only on the temperature measurement result, the compressor 2 will be turned OFF at the time point 2 in FIG.

In this way, a phenomenon occurs in which the compressor 2 is repeatedly turned ON and OFF, but in order to eliminate such malfunctions, the present invention is designed to turn the compressor 2 ON or OFF.
TX for a certain period of time after switching to FF (usually 15 seconds to 1 minute)
A timer is provided inside the microcomputer MC so that the state of the compressor 2 is maintained regardless of the temperature measurement result.

A clock input for this purpose is applied to the clock terminal CLK in FIG.

As shown in Figure 2, the reference potential v1 rotates to its normal value as the power supply voltage vO returns, but if the fixed time TX is set longer than this recovery completion time, such malfunctions can be completely prevented. can.

As mentioned above, there is a sensor-based control logic that turns the compressor 0N-OFF by comparing the room temperature, ON point, and OFF point, and a prohibition of 0N-OFF switching for a certain period of time when the compressor is switched 0N-OFF. By combining this with timer-based control that performs the following, even if the analog circuit malfunctions due to power supply voltage fluctuations, the overall operation can be performed normally without malfunction.

FIG. 4 is a functional block diagram based on the embodiment shown in FIG. 1.

In FIG. 4, reference numeral 5 denotes a control section, which is composed of a microcomputer-MC.

Reference numeral 6 denotes a room temperature detection section, which consists of a thermistor RT and a capacitor C2, which are surrounded by a dotted line 4 in FIG.

Reference numeral 7 denotes a comparison detector, which consists of IC1 and temperature setting volume VB shown in FIG. 1, and further includes a control signal from a control section.

is also input as necessary, the input from the room temperature detection section is compared with the set temperature, and the result is provided to the control section.

This comparison detector may be included in a microcomputer, such as a microcomputer with a built-in comparator or an analog-to-digital converter.

Reference numeral 8 denotes a part of an inhibition timer configured by a program in the microcomputer.

The time base of the timer is given to the input CLK of the microcomputer from the power supply circuit.

The operation of a portion of this prohibition timer is controlled by a logic section configured by a program within the microcomputer.

The logic part 9 is connected to the compressor 1 according to the invention as described above.
Controls output to 0.

FIG. 5 shows a flowchart of the main part of a program showing an embodiment of the present invention.

The figure mainly shows a flowchart for the prohibition timer part 8 and the logic part 9, and the signal that the prohibition timer part outputs for a certain period of time writes 1 to the memory configured inside the microcomputer. A known flag is used to indicate whether a signal is served or not, and in this case, the flag is particularly called a 6-prohibited timer flag.

The flow shown in FIG. 5 will be explained.

For the sake of simplicity, it is assumed that the compressor is stopped, a sufficient amount of time has elapsed, the prohibition timer has also elapsed for a certain period of time, and the "prohibition timer flag" has also become zero.

Therefore, the determination in 12 becomes key 1, and in the part 13 on the right, it is determined whether or not to change the compressor from on to on or from off to on based on the input from the room temperature comparison detector. , if you need to change it,
14 gives the necessary output to the compressor, 15 resets a part of the prohibition timer, and 16 sets the "prohibition timer flag".
is set to 1, other processing 17 is performed, and the process returns to 12.

At this time, in step 16, the prohibition timer flag is set to 1, so it goes down, and in step 18, the prohibition timer is counted up, for example, every second, and in step 19, when the predetermined time has elapsed. It is determined whether or not the time has elapsed, and if the time has elapsed, the "prohibition timer flag" is set to 0 at 20.

Therefore, until the prohibition timer elapses for a predetermined time, 12
Since it does not move toward 13 at the 0 portion, it is used as a room temperature comparison detector and the compressor is not controlled.

However, if the user wants to forcibly turn off the compressor by inputting an operation, it is necessary to perform the other processing shown in 11.

Further, FIG. 3 shows a room temperature measuring circuit in another embodiment of the present invention.

In FIG. 3, MC is also a microcomputer, and the thermistor RT is also provided with a capacitor C2 for noise removal.

The room temperature is converted into a digital signal by an analog-to-digital converter ADI and read into the microcomputer MC.

Further, the set value to be compared is determined by the variable resistor VR, and is read into the microcomputer MC through the same A/D converter.

The compressor is turned ON or OFF by a logical judgment based on these two data, but in this case as well, it is necessary to provide the above-mentioned compressor ON-OFF switching prohibition time.

This is because there is a capacitor C2 on the room temperature measurement side, so there is little effect from fluctuations in the power supply voltage, but on the other hand,
This is because the set value reading side is directly affected by fluctuations in the power supply voltage.

Further, in the above explanation, an example using a microcomputer was shown, but of course this can also be realized using wired logic.

Also, the method of providing reference potentials for the ON point and OFF point of the compressor can be realized without using the open drain output of the microcomputer as in this example, or by forming a bridge with a different reference potential. This can also be achieved by switching the resistance using a relay.

However, as long as a capacitor is connected in parallel to the thermistor, there is a risk that the malfunction described in the present invention will occur, so it is clear that the present invention can be used.

As is clear from the description of the embodiments above, the air conditioner of the present invention combines sensor-based and timer-based control, so it is possible to protect the system from malfunctions due to power supply voltage fluctuations. Even if a malfunction occurs in the room temperature measurement circuit, the data at that time is not used, so the compressor will not malfunction, and there is no need to prevent malfunctions due to voltage fluctuations in the room temperature measurement circuit, so the circuit is simple. It has the effect of becoming

[Brief explanation of the drawing]

FIG. 1 is a control circuit diagram of an air conditioner according to an embodiment of the present invention, FIG. 2 is a time chart for explaining the operation of the control circuit, and FIG. 3 is a main part of another embodiment of the present invention. FIG. 4 is a block diagram of the embodiment shown in FIG. 1, and FIG. 5 is a flowchart of the same program. vO...Control circuit voltage, vl...Reference potential, V2...F point potential, v3...Output, TX...Compressor 0N -OFF switching prohibition time, RT... curve thermistor, C2... thermistor parallel resistance, 1... power supply, 2... °...
·compressor.

Claims (1)

[Claims] 1 A room temperature detection section having a capacitor connected in parallel to the thermistor is provided, a comparison detector is provided to compare the output voltage of the room temperature detection section with a room temperature set value, and the compressor is turned on.
, a control unit for controlling OFF, and the control unit includes a prohibition timer portion that outputs a signal until a certain time elapses from the time when the compressor is turned ON or OFF, and the control portion outputs a signal from the prohibition timer portion. An air conditioner comprising a logic section that does not control ON or OFF of the compressor based on the signal from the comparison detector while the comparison detector is outputting the compressor.