JPS594613B2 - How to control an air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] The present invention relates to a method of controlling an air conditioner equipped with a compressor whose capacity can be controlled in two stages.

[Background of the Invention] As shown in Fig. 1, in the conventional air conditioner of this type, the indoor temperature range is divided into two stages, a low temperature range and a high temperature range, and in the former range, high capacity operation of the compressor In the latter region, room temperature is controlled by operating the compressor at low capacity.

In this case, if the room heating load is greater than or less than the heating capacity of the compressor during high capacity operation, and greater than the heating capacity during low capacity operation, the indoor temperature will be controlled within the low temperature range. Ru.

On the other hand, when the indoor heating load is smaller than the heating capacity of the compressor during low capacity operation, the indoor temperature is controlled within the high temperature range.

As mentioned above, there is a possibility that there are two control regions for the indoor temperature depending on the indoor heating load.

For this reason, when the indoor heating load increases, the room temperature is controlled in a low temperature range, making the room feel colder.

Conversely, when the indoor heating load decreases, the room temperature is controlled in a high temperature range, making it feel warmer.

As described above, the sense of temperature varies depending on the indoor heating load, which has the disadvantage of causing discomfort.

[Purpose of the invention]

The present invention aims to eliminate the above-mentioned drawbacks, provide comfortable air conditioning, and improve energy saving effects.

[Summary of the invention]

In an air conditioner equipped with a compressor whose capacity can be controlled in two stages, the present invention measures the elapsed time from the heating start room temperature to the heating stop room temperature during high capacity heating operation of the compressor, and measures the measured value. When is above a certain value, heating is restarted by operating the compressor at high capacity.

[Embodiments of the invention]

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

The heating load in the control method of the present invention is measured by providing a timer and measuring the operating time required for a constant change in indoor temperature.

The method of measuring the operating time and switching the operation will be explained in detail with reference to FIGS. 2 to 8.

These figures are graphs with room temperature T on the vertical axis and time t on the horizontal axis, where T8 is the room temperature at the start of heating operation, To
is the operation stop room temperature, to is the time required to change from T8 to TF, and t'o is a constant value of the required time.

(1) Heating load > Heating capacity during high capacity operation In this case, as shown in Figure 2, the room temperature T is the heating stop temperature TP,
is not reached, so the compressor continues to operate at high capacity.

(11) High Capacity Operation Heating Capacity> In the case of heating load In this case, as shown in FIGS. 3 to 6, the room temperature T reaches the operation stop temperature T0 due to the high capacity operation of the compressor.

If the heating load is close to the heating capacity during high capacity operation, the time t required for the room temperature to change from T8 to TF.

is long. Therefore, as shown in Figure 3, the required time t
.

is a constant value t. Assuming that the indoor heating load is comparable to the heating capacity of the compressor during high-capacity operation, the room temperature can be lowered from T8 to T by repeating high-capacity operation and stop of the compressor.
It can be held between 00 and 00.

As shown in FIGS. 4 to 6, the required time t.

is not so long and is shorter than the constant value t10, the room temperature T while the compressor is stopped.

Measure the time tf required for the temperature to drop to T8.

Here, the heating capacity during high-capacity operation is QH%.If the indoor heating load is L, and the value is almost constant within a short time, then the amount of heat added to increase the indoor temperature and the amount of heat added to reduce the indoor temperature are Therefore, the amount of heat removed is almost equal, and the following relationship holds.

Here t.

/1f-1, then from equation (1), L is becomes.

Also t. If we assume that /1f=2, L is similarly becomes.

Further, due to the characteristics of the refrigeration system, the following relationship approximately holds true between the heating capacity QH of the compressor during high-capacity operation and the heating capacity Qt of the compressor during low-capacity operation.

Therefore, the switching point between high-capacity heating operation and low-capacity operation heating of the compressor is t from equations (3) and (4).

/lf22.

But t. If /l f=2 is set as the switching point, if the heating load increases during low capacity operation, there is a risk that the room temperature will drop immediately.

Therefore, the conditions under which the room temperature does not drop immediately even when switching to low capacity operation are yh/7'-11-, Ii, h Buna, Suima, to/lf as tp, and tP and t.

/14, and if tP >"'-, the next heating operation will be performed in high capacity operation of the compressor as shown in Fig. 4f, and if tP>b-, the As shown in the figure f, the next heating operation is performed with the compressor running at a low capacity, and thereafter the low capacity operation is continued, or the operation and stop are repeated as shown in Figure 6.

As a result, it is possible to perform high-capacity operation and low-capacity operation of the compressor appropriate to the indoor heating load, and to control the indoor temperature within a certain range.

Next, the case where the heating load increases and the compressor is switched from low-capacity operation to high-capacity operation will be explained with reference to FIGS. 7 and 8.

By switching the compressor from high capacity operation to low capacity operation,
Even if the value of tP is selected so that the room temperature does not drop immediately with a slight increase in the load, the heating load changes significantly between day and night.

Therefore, if the heating load increases significantly while the compressor is operating at low capacity, the room temperature will drop and the compressor must be switched to high capacity operation.

This will be explained in more detail below.

(e) When the load suddenly increases In this case, as shown in Figure 7, the room temperature T at the start of heating operation is
8. Set a lower room temperature T8'.

If the load suddenly increases, the room temperature T will also drop rapidly, so if the room temperature T drops to T8' while the compressor is operating at low capacity, an emergency situation may occur. Forcibly switch to high capacity operation.

CB) When the load gradually increases In this case, as shown in Figure 8, immediately after switching the compressor from high capacity operation to low capacity operation, the room temperature will decrease because the heating capacity has a margin compared to the heating load. Although T increases, the room temperature T decreases as the load increases.

Therefore, a timer is used to set the compressor's low capacity operation time tON.
′ is measured, and from this a certain time t is measured.

If the room temperature T after N' has elapsed is equal to or still below the room temperature T8 at the start of low capacity operation of the compressor, it is determined that the low capacity operation heating capacity of the compressor has fallen below the heating load; Switch the compressor to high capacity operation.

Although the above explanation has been about switching from low capacity operation to high capacity operation of the compressor, it goes without saying that the compressor continues to operate at low capacity under conditions other than the above.

A specific example of implementing the above-mentioned functions will be explained with reference to FIG. 9. 1 is a room temperature sensor that measures the room temperature of the space to be heated, 2 is a control device that executes the control logic, and 3 is a device that heats the space to be heated. This is an air conditioner equipped with a two-stage compressor whose capacity can be controlled.

The room temperature is measured by the room temperature sensor 1, and then the control device 2 determines whether the compressor of the air conditioner 3 is in high capacity heating operation, low capacity operation heating, or shut down according to the control logic, and controls the air conditioner 3. Because it sends a signal,
The air conditioner 3 is operated according to this control signal.

The operational logic of the functional blocks within the control device 2 can be easily realized by a combination of known logic circuits.

An example will be explained below. The control device 2 includes a temperature comparator that switches the output signal from 0 (stop signal here) when room temperature T>T to 1 (operation signal here) when room temperature T8 based on a known hysteresis characteristic. 11. Temperature comparator 12 that generates signal 1 when room temperature T <T8; Temperature comparator 1 that generates signal 1 when room temperature T <: Ts'
3. It is activated only when the output signal of the temperature comparison section 11 becomes 1, and the switching judgment section 14, which determines switching from high capacity to low capacity, is activated when the output signal of the temperature comparison section 12 becomes 1. , operates until the output signal becomes 0, and is activated when the output signal of the switching judgment section 15, which determines switching from low capacity to high capacity, and temperature comparison section 13 becomes 1, and the output signal becomes 0. The logical product of the input signals from the switching unit 16, the temperature comparison unit 11, and the switching judgment units 14, 15, and 16, which performs a forced switching operation to high capacity, is output as a signal for operation 1 or stop 0. Logic section 17, switching section 1
6, 17. While the input signal from 18 is stored as a signal of high capacity 1 or low capacity 0, and the storage drive unit 18 which sends the stored contents to the compressor 3 as an operating capacity signal, and a timer 21 to be described later are operating. After the timer 21 completes its operation, the drive unit 19 delays the output signal of the logic unit 17 by a small amount of time (for example, about 1 second) and sends the stop signal to the compressor 3 of the air conditioner as an operation or stop signal. The stop time measurement timer 20 is activated when the output signal of the comparator 11 becomes 0, operates until the set time elapses or the output signal becomes 1, and the elapsed time can be read out, and the output of the drive section 19. It starts when the signal falls to 0 and operates until the set time elapses, allowing you to identify the elapse of the set time and prevent the air conditioner from frequently starting and stopping within a short period of time. The timer 21 is started when the output signal of the drive section 19 becomes 1, operates until a set time elapses or the output signal becomes 0, and is equipped with a timer 22 for measuring operating time, from which the elapsed time can be read. ing.

Note that the signals (not shown) used by the switching determination units 14, 15, and 16 during operation will be described in detail in the operation explanation section below.

In the above configuration, the room temperature is measured by the room temperature sensor 1, and then the air conditioner 3 is controlled by the control device 2.
The air conditioner 3 determines high-capacity operation heating, low-capacity operation heating, and operation stop of the compressor according to the control logic.
The air conditioner 3 is operated in accordance with this control signal.

The operation of the control device 2 will be explained in detail below.

The explanation will begin from a state in which the heating operation is started by turning on the main power supply (not shown) in a state where the room temperature is T<T8'.

It is assumed that all internal states of the control device 2 are reset immediately after the main power is turned on.

Since the room temperature is T8', the temperature comparator 11 generates the operating signal 1, and this signal is sent to the logic section 17.
If the signals from the switching determination units 15 and 16 that are input to the logic unit 17 at the same time are both 1, they are sent to the drive unit 19, but since the drive unit 19 gives a certain delay to the sending of this signal,
The drive unit 19 does not send out the driving signal 1.

At the same time, the switching determination section 14 is driven at the rising edge of the operation signal of the temperature comparison section 11.

The switching determination unit 14 first checks the driving ability signal stored in the storage drive unit 18, and if this is a high ability signal, checks the elapsed time of the driving time timer 22 and sets it to a predetermined value t.

', the relationship between the elapsed time of the operation time timer 22 and the stop time timer 20 is checked, and if the predetermined relationship is satisfied, a low capacity signal is generated and the memory of the memory drive unit 18 is Change the content.

However, in this case, since the storage content of the storage drive unit 18 is the low capacity signal O, the above-mentioned capacity switching signal is not generated.

Since the room temperature is T8', the temperature comparator 12 also generates an operation signal to operate the switching determination section 15.

If the stop signal is 0, a high performance signal 1 is generated, the memory of the storage drive unit 18 is changed, and the memory of the stop signal 0 generation is canceled.

Therefore, if the output signal of the drive unit 19 is the stop signal 0 when the switching determination unit 15 operates, the above logic does not hold, and the stop signal 0 is not generated, so there is no memory of the generation of the stop signal 0. Therefore, no operation signal is generated.

In the current case, the output signal of the drive unit 19 is the operation signal 1 and the above logic is established, so the operation signal according to the above logic is generated.

That is, the operation of the air conditioner 3 is stopped for one phase,
High capacity operation is resumed after the elapsed time of the timer 21.

This corresponds to the case in FIG. Finally, a case will be described in which the room temperature suddenly drops during low capacity operation and the temperature comparator 13 operates.

In this case, the switching unit 16 operates, and if the storage content of the storage drive unit 18 is a low ability signal 0, it generates a stop signal 0 and transmits it to the logic unit 17.

If the output signal of the drive section 19 is a stop signal 0, a high capacity signal 1 is generated and the memory of the memory drive section is changed.

If you are thinking about it now, the above logic holds true.The switching judgment unit 15 first checks the memory signal of the memory drive unit 18, and determines that the low capacity signal is 0 and the elapsed time of the operation time timer 22 is a predetermined value t.
.

If the output signal of the drive section 19 is the operation signal 1 when the output signal exceeds N, the stop signal 0 is generated and transmitted to the logic section 17, and the generation of the stop signal 0 is stored.
If the output signal of the drive unit 19 is a stop signal 0, a high capacity signal 1 is generated, the memory of the memory drive unit 18 is changed to the high capacity signal 1, and the generation of the stop signal 0 is memorized. Release.

That is, the air conditioner 3 is operating at low capacity, and the elapsed time is the predetermined value t.

If it exceeds N, the capacity signal is switched to the high capacity signal 1 after stopping the operation of the negative air conditioner.

If the above conditions other than this do not hold, the switching judgment unit 15
The operation signal 1 is always sent to the logic section 17.

In this way, in the present invention, the ability switching signal is always generated only when the drive section 19 is outputting the stop signal 0, but when the drive section 19 is outputting the operation signal, In an air conditioner in which there is no problem in driving the compressor even if the capacity is switched, the above-mentioned stop signal generation processing section can be omitted.

In the state currently being considered, the operating time timer 22 is not operating again, so the switching determination section 15 does not operate at all and merely transmits the operating signal 1 to the logic section 17.

Since the room temperature T<TS', the temperature comparison section 13 also generates an operation signal, and the switching section 16 starts operating.

The switching unit 16 first checks the storage signal of the storage drive unit 18, and if the low capacity signal is 0, generates a stop signal 0 and sends it to the logic unit 17, and at the same time checks the output signal of the drive unit 19. If the stop signal is 0, a high capacity signal 1 is generated and the memory in the storage drive unit 18 is changed to the high capacity signal.

When the above conditions are not met, an operation signal is always sent to the logic section 17.

The timing of this operation is the same as that described for the switching determination section 150.

In the state currently being considered, the memory signal of the nose moving section 18 is a low-performance signal, so a stop signal 0 is generated and sent to the logic section 17, but the output signal of the drive section 19 is a stop signal. 0, the transmission of the stop signal 0 has nothing to do with it, and the high capacity signal 1 is immediately generated to change the memory of the memory drive unit 18.

As a result, the switching logic of the switching section 16 no longer holds true, so the operation signal 1 is generated and transmitted to the logic section 17.

In this way, immediately before operation in a state where the room temperature T<T8', the high performance signal 1 is set in the storage drive section 18 and transmitted to the air conditioner 3.

In this state, all the input signals to the logic unit 17 are 1, so the drive unit 19 generates an operation signal after a certain delay and starts high-capacity operation of the air conditioner, and also Timer 22 is started.

After the start of operation of the air conditioner, the state of the control device 2 does not change at all during the process in which the constant temperature rises. Therefore, when the room temperature becomes T>TE, the temperature comparator 11 operates and the stop signal 0 is output. High-capacity operation will continue unless generation occurs.

This is the operating state shown in FIG. Next, high capacity operation continues for a predetermined time t.

A case will be described in which the temperature comparator 11 operates and a stop signal 0 is generated after the temperature has continued for 7 or more times.

The signal from the temperature comparison section 11 passes through the logic section 17 and then is outputted as a stop signal 0 by the drive section 19 after a certain delay, and the operation of the air conditioner is stopped, and the operation of the timer 22 is also stopped. The operation of the timer 21 is started.

Further, the timer 20 is also activated at the same time as the temperature comparison section 11 operates.

When the room temperature drops to T8 while the operation is stopped, the temperature comparator 11 operates again to generate the operation signal 1, which is sent to the drive unit via the logic unit 17, but the drive unit as described above immediately does not work.

If the timer 21 is in operation, the start of operation is further extended until the timer setting time has elapsed.

Due to the operation of the temperature comparison section 11, the operation of the timer 20 is stopped, and the switching determination section 14 is activated.

The switching determination unit 14 confirms that the storage signal of the storage drive unit 18 is the high performance signal 1 and that the elapsed time of the timer 22 exceeds a predetermined value, and does not generate any operation signal.

At the same time, the temperature comparison section 12 operates, and the switching judgment section 15
However, since the storage signal of the storage drive section 18 is not the low capability signal 0, the switching judgment section 15 also does not generate any operation signal.

Therefore, the constant delay removal drive unit 19 operates, and the operation of the air conditioner is resumed at the same high capacity as the previous time.

This corresponds to the case in FIG.

Next, high capacity operation continues for a predetermined time t.

A case in which the temperature comparator 11 operates within the following time will be described.

The process up to the point where the room temperature drops, the temperature comparator 11 operates, and generates the operation signal is as described above.

Similar to the above, the switching determination section 15 operates, but does not generate any operation signal.

The switching determination unit 14 also operates.

In this case, the storage signal of the memory 7 drive unit 18 is the high performance signal 1, and the elapsed time of the timer 22 is less than the predetermined value to', so the elapsed times of the timer 22 and timer 20 are compared.

If the above-mentioned predetermined relationship is not satisfied, no operation signal is generated, and high-capacity operation as before is resumed.

This shows the case of FIG. When the above-mentioned predetermined relationship is satisfied, the switching determination unit 14 generates a low capability signal 0 and changes the memory in the storage drive unit 18.

Therefore, when the operation is resumed, it will be operated at a low capacity.

This corresponds to the case in FIG. Next, a case will be described in which the room temperature rises during low capacity operation and the temperature comparator 11 operates.

This is also the same until the temperature drops and the temperature comparator 11 generates the operation signal 1.

In this case, the temperature comparison section 12 starts the operation of the switching judgment section 15, but since the output signal of the driving section 19 is the stop signal 0, the switching judgment section 15 does not generate any operation signal.
When operation resumes, it will be operated at low capacity as before.

This corresponds to the case in FIG.

Next, consider a case where the room temperature does not rise during low capacity operation and the temperature comparator 12 operates.

In this case, the operation of the switching judgment unit 15 is started, but the switching judgment unit 15 checks the storage signal of the storage drive unit 18 and determines that it is a low capability signal and the elapsed time of the timer 22 is equal to or greater than the predetermined value tO8. Do the following:

If the output signal of the drive unit 19 is the operation signal 1, the stop signal is 0.
It generates and transmits it to the logic section 17, and also stores that the stop signal 0 has been generated.

Since there is a memory of generating a stop signal 0 and the output signal of the drive section 19 is generated, first a stop signal 0 is generated and the operation of the air conditioner 3 is stopped, and then the memory of the memory drive section 18 is changed. Ru.

Then, since the above logic no longer holds true, an operation signal is transmitted to the logic section 17.

Therefore, as in the case of FIG. 8, high capacity operation is resumed after the elapsed time of the timer 21.

This corresponds to the case in FIG.

〔Effect of the invention〕

As explained above, the indoor heating load can be indirectly measured by measuring the operating and stopping times of the compressor for a constant change in room temperature, and the capacity of the compressor can be controlled to match the heating load. I can do it.

Therefore, it is possible to achieve comfortable air conditioning by reducing the range of fluctuations in room temperature, extend the life of the compressor by avoiding unnecessary changes in compressor capacity, and improve energy efficiency during heating operation. can.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the heating operation range of the compressor in a conventional air conditioner, FIGS. 2 to 8 are diagrams explaining the control method of the air conditioner of the present invention, and FIG. 9 is a diagram showing the control method of the present invention. 1 is a block diagram of an example of a control device suitable for the method; FIG. 1... Room temperature sensor, 2... Control device, 3... Air conditioner.

Claims (1)

[Claims] In an air conditioner equipped with a compressor that can be controlled in 12 stages, the elapsed time from the heating start room temperature to the heating stop room temperature is measured during high capacity heating operation of the compressor, and this elapsed time and When the difference or ratio between the elapsed time from the heating stop room temperature to the heating start room temperature after the heating stops is greater than a certain value, the heating restart is started with high capacity operation of the compressor, and the difference or ratio is set to a certain value. A method for controlling an air conditioner, characterized in that, in the following cases, heating restart is started with low capacity operation of a compressor.