JPH031032A - Control device for heat pump type air conditioner - Google Patents

Abstract

PURPOSE:To reduce the frequency of a current release at a second stage at which an indoor fan is switched to HIGH by a method wherein when the current of a motor is increased to a first set value, an outdoor fan motor is stopped, and when it is increased to a second set value, an indoor fan is forcibly switched to HIGH operation. CONSTITUTION:An additional set value I to a current IC of a compressor motor 1M detected by a current detector 15 is set, and IC + I is compared with a first set value I1 at which an outdoor fan 5F is stopped. The magnitude of the additional value I is set so that a formula of I <I1 - I3 is established in relation between first and third set values I1 and I3. As a result of the compar ison, the case of IC+ I<I1, normal operation is continued. In the case of I1 + I >= I1, in current release control at a first stage, OFF, i.e. a stop of opera tion, of an outdoor fan motor 5M is first effected. Thereafter, the current IC itself is compared with a second set value I2 at which an indoor fan 3F is switched to HIGH or a third set value I3 at which the indoor fan 3F is returned to LOW or the outdoor fan motor 5M is brought into an ON-state.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a control device for a heat pump type air conditioner, more specifically, a control device for a heat pump type air conditioner, and more specifically, a compressor and a control device for switching between at least strong wind operation and weak wind operation. The refrigeration cycle includes an indoor heat exchanger that has an indoor fan and functions as a heat sink, and an outdoor heat exchanger that has an outdoor fan and functions as a heat absorber. The fans are each driven by a compressor motor, an indoor fan motor, and an outdoor fan motor, and the heat pump air conditioner controls each motor according to a predetermined program so that the deviation between the detected temperature in the room to be heated and the set temperature is zero. The present invention relates to a control device.

(Prior Art) FIG. 7 shows a typical system configuration of a refrigeration cycle that constitutes the above-mentioned heat pump type air conditioner. Fig. 7 shows a refrigeration system that is equipped with a four-way switching valve 2 on the intake and exhaust side of the compressor 1, and by switching it can perform both heating operation (solid line arrow) and cooling operation (dashed line arrow). It shows a cycle. During heating operation, which is the object of the present invention, refrigerant flows from the compressor 1 to the four-way switching valve 2, to the indoor heat exchanger 3, to the expansion valve 4, to the outdoor heat exchanger 5.
The air flows through the four-way switching valve 2 in the direction of return to the compressor 1. The indoor heat exchanger 3 includes an indoor fan 3F, and functions as a radiator during heating operation. Although not shown here, the indoor fan 3F is configured so that it can be operated in multiple stages, for example, in two stages: strong wind (H) and weak wind (L). .

The outdoor heat exchanger 5 includes an outdoor fan 5F, and functions as a heat absorber during heating operation. In addition, during cooling operation,
Refrigerant flows from the compressor 1 through the four-way switching valve 2, the outdoor heat exchanger 5, the expansion valve 4, the outdoor heat exchanger 3, and the four-way switching valve 2 in a direction in which it returns to the compressor 1. In this case, the indoor heat exchanger 3 functions as a heat absorber, and the outdoor heat exchanger 5 functions as a radiator.

In the refrigeration cycle shown in FIG. 7, the compressor 1 is driven by a compressor motor IM, and the indoor fan 3
F is driven by the indoor fan motor 3M, and the outdoor fan 5F is driven by the outdoor fan motor 5M. Indoor fan motor 3M is strong wind (H) of indoor fan 3F.
・It shall have means for switching the rotation speed according to the operation of light wind (L), such as a winding tap and a changeover switch.

Now, in the refrigeration cycle shown in Fig. 7, the load on the compressor 1 is detected by the current flowing through the primary side of the compressor motor IM, and as the detected current increases and reaches a certain set value, the load is reduced. , a method is known in which the outdoor fan motor 5M is stopped as the first step. Despite the outdoor fan motor 5M stopping,
If the current of the compressor motor 1M increases further, the indoor fan motor 3M is switched to the strong direction as a second step. This method of turning on/off or switching the intensity of the indoor fan motor 3M to the outdoor fan motor 5M based on the detected current of the compressor motor 1M is known as a current release method.

(Problems to be Solved by the Invention) In the above-described refrigeration cycle, the rotational speed of the indoor fan motor 3M, that is, the operating intensity of the indoor fan 3F, is in principle determined by the user's settings.

However, in the control method based on the first and second stage control modes described above, for example, the user initially
)”, when entering the second stage, the “strong wind (
H)”. It goes without saying that such a control method, in which the machine unilaterally changes the user's settings, should be avoided if possible, since it gives the user a sense of discomfort. However, if the refrigeration cycle piping distance is long,
For example, when the piping distance between the indoor unit including the indoor heat exchanger 3 and the outdoor unit including the outdoor heat exchanger 5 is long, the compressor motor IM is turned on and off to turn on and off the refrigeration cycle, that is, the compressor 1 on/off
Even if it is turned off, the followability of the behavior of the refrigerant circulating in the refrigeration cycle will deteriorate.

Therefore, even if control is performed using the first stage control mode,
The current of the compressor motor IM does not always drop quickly, and the control is often inadvertently carried out using the second-stage control mode.

This control mode will be explained with reference to FIG.

In Fig. 3, the horizontal axis shows time T, and the vertical axis shows the current of the compressor motor M! (Hereinafter, this will be referred to as C load current I). For the load current ■, the first set value ■1 is used to stop the outdoor fan 5F to reduce the current, the second set value I2 is used to switch the indoor fan 3F to the strong wind side, and the indoor fan 3F is switched to the weak wind side. A third set value I3 is set for returning to the normal state and restarting (returning) the outdoor fan 5F. The correlation between these setting values is Ia < I t < 12.

As shown by the broken line, the load current l gradually increases from the region I<11, and when it reaches the first set value 1□, the outdoor fan 5F is stopped. However, in this case, if the followability of the refrigerant behavior is poor, the load current 18 will continue to increase and eventually reach the second set value I2, causing the indoor fan 3F to be switched to the strong wind side. Become. Only after this switching does the load current l begin to decrease.

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a control device for a heat pump type air conditioner that can suppress the frequency of reaching the second stage control mode as much as possible.

[Structure of the invention]

(Means for Solving the Problems) A control device for a heat pump type air conditioner according to the present invention is an indoor heat exchanger that has a compressor and an indoor fan that can be switched between at least strong-wind operation and weak-wind operation, and functions as a radiator. The refrigeration cycle includes an outdoor heat exchanger that has an outdoor fan and functions as a heat absorber, and the compressor, indoor fan, and outdoor fan are each driven by a compressor motor, an indoor fan motor, and an outdoor fan motor. In a control device for a heat pump type air conditioner that controls each motor according to a predetermined program so as to zero the deviation between the detected temperature of a room to be heated and the set temperature, the current detection means detects the current of a compressor motor. and a current setting means for setting a relatively small first set value and a relatively large second set value according to the magnitude of the compressor current, and an increase in the current detected by the current detecting means. Accordingly, when the value obtained by adding a predetermined value to the current reaches the first set value as a first step, the outdoor fan motor is stopped, and the current of the compressor motor is further increased despite the stoppage of the outdoor fan motor. The present invention is characterized by comprising a control means for forcibly switching the indoor fan to strong wind operation when the second set value is reached.

(Function) In the control device for a heat pump type air conditioner according to the present invention, as explained with reference to FIG.
Setting value ① of 1 is not directly compared with 1, but a certain value, that is, an additional setting value ΔI is considered, and as shown by the solid line A, 1. When +ΔI reaches the first set value It, the outdoor fan motor is stopped. That is, the condition for stopping the outdoor fan motor is set as summer +ΔI≧11. After the outdoor fan motor is stopped, the additional set value Δl is ignored and the original current I 2 is compared with the second set value (2) even if the current I 2 increases further. In other words, when the outdoor fan motor is stopped, it will start from a load current point P that is smaller by the additional set value Δ■ than the set value ■1, and there will be a time margin of Δt compared to when the additional set value ΔI is not considered. You can have it. The second set value I2 is increased by this margin time Δt.
This can reduce the frequency at which this happens.

(Example) The present invention will be described below with reference to the drawings.

FIG. 2 shows each motor in the control device for a heat pump type air conditioner according to the present invention, that is, an indoor fan motor 3M.
, outdoor fan motor 5M and compressor motor IM
and shows the control device 10. Indoor fan motor 3
M, outdoor fan motor 5M and compressor motor I
M is connected to AC power supply 11 via switches 12a-, 12b, 12c, switch 13, and switch 14, respectively. The indoor fan motor 3M is 3 here.
It is shown as being selectively switchable between stages: light wind (L), medium wind (M), and strong wind (H). Each of these switches is controlled by a control device 10 consisting of a microcomputer. Current of compressor motor M■. is detected by the current detector 15, and the detected current signal is introduced into the control device 10. The control device 10 is
In addition to the detection current signal, various sensor outputs, such as the detection output of the room temperature sensor 6, are also input, and after performing predetermined calculation processing, the electromagnetic Controls valves, etc.

Next, the current release method performed according to the present invention will be explained with reference to FIGS. 1 and 3.

In addition, in the following explanation, stopping and running the compressor motor 1M corresponds to that of the compressor.
Similarly, the strong and weak operation of the indoor fan motor 3M corresponds to that of the indoor fan 3F, and the on/off operation of the outdoor fan motor 5M corresponds to that of the outdoor fan 5F.

First, an additional set value ΔI is set for the current ■ of the compressor motor M detected by the current detector 15, and a comparison between ■ +ΔI and the first set value 11 for stopping the outdoor fan 5F is performed ( Step Sl, S2)
. The magnitude of the additional set value ΔI is set to be equal to the first and third set values 11.1 to prevent hunting in the control operation. I3
In the relationship, it is set so that ΔI<ll−I3. As a result of the comparison in step S2, I +ΔI<I
If t (step S2: "Y"), normal operation is continued (steps 53-5l-32-83...). ■ ＋
When Δ■≧Il (step S22 “N”), the outdoor fan motor 5 is first controlled as the first stage current release control.
M is turned off, that is, the operation is stopped (step S4)
. The present invention is characterized in that the outdoor fan motor 5M is turned off by the first stage current release (point P) earlier by a time Δt than in the conventional system (point Y) shown by the broken line. After this, the additional set value ΔI is ignored and the current!
itself, and a second setting value I2 for switching the indoor fan 3F to the strong wind side, or a third setting value 13 for returning the indoor fan 3F to the weak wind side, or operating the outdoor fan motor 5M. A comparison is made (steps S5°S6.S7.S9). Even if the current I continues to increase as shown in FIG. 3 after the outdoor fan motor 5M is turned off in step S4, in most cases, ! , <1
The effect of stopping the outdoor fan 5F in the range 2 becomes apparent, and there is almost no need to switch the indoor fan motor 3M to the strong wind side (high speed side).

However, Io≧12 (step S7: “N
”), the indoor fan motor 3M is switched to the strong wind side (H side) as a second stage current release (step S8).

Also,! . When I0≦13 (Step S9: "N") within the range of I2 (Step S7: 'Y'), the indoor fan motor 3M is returned to the weak wind side (H side) (Step 510).

The current I decreases to I<13 (step S6:
"Y"), the outdoor fan motor 5M is turned on (step 511).

According to the above embodiment, as can be easily seen from FIG. 3, the frequency at which the compressor current I reaches the second set value I2 and the second stage of current release, that is, the strong wind operation of the indoor fan 3F, is greatly increased. can be reduced to

Although not shown in the diagram, a general abnormal current protection means against the compressor motor current (such as short circuit and overcurrent protection) shall be separately provided, and if it is activated, the power circuit breaker ( (not shown) is turned off.

FIG. 4 shows another embodiment of the invention.

In this embodiment, the fourth setting value 14 is set near the rated value for the current I, and in a control device provided with means for turning off the compressor motor M when I0≧I4, the first When the outdoor fan motor 5M is stopped as a step current release (step S4), the current l increases even more due to the poor followability of the refrigeration cycle, resulting in a situation where the compressor stops. In order to prevent this as much as possible, a step S12 is provided after step S4 in which the function of the fourth set value I4 is stopped for a time T of several tens of seconds, for example, 60 seconds. The rest is the same as the embodiment shown in FIG.

Even if you set the stop time of the current release function to this extent,
This does not interfere with the protective operation against an increase in current during abnormal conditions.

In this embodiment as well, it is possible to prevent the compressor from stopping as much as possible due to an increase in current caused by poor followability of the refrigeration cycle.

In the embodiment shown in FIG. 4, step 12 is provided in addition to the embodiment shown in FIG. 1 in which the additional setting value ΔI is set.
It can also be applied when l is not set.

In the embodiments shown in FIGS. 1 to 3, the additional set value Δl is set in the control device 10, but a different embodiment is shown in FIGS. 5 and 6. In FIG. 5, a common current detector 17 is provided for the compressor motor IM and the outdoor fan motor 5M to detect the total current IL of both motors IM and 5M and introduce it to the control device 10. If there is a common electric wire between the compressor motor IM and the outdoor fan motor 5M as shown in the figure, one current detector 17 may be provided for the common electric wire as shown in the figure. If they are arranged separately, for example, a through-type current transformer may be used as the current detector 17, and both electric wires may be passed through the through-hole in common.

In this embodiment, out of the total current I, the current component of the outdoor fan motor 5M fulfills the function in place of the additional set value Δ■ in the embodiments of FIGS. 1 to 3, so it is shown in the flow chart of FIG. As such, the current in the embodiments of FIGS. 1-3! By using the current IL instead of the current I, the same effect as that explained with reference to Fig. 1 can be obtained.
effect can be achieved.

〔Effect of the invention〕

According to the present invention, as detailed above, when the outdoor fan is stopped to reduce the current of the compressor motor, the outdoor fan is stopped early before reaching the set value for the original first stage current release. Therefore, even in a situation where the followability of the refrigeration cycle is poor and the compressor motor current increases further, after the outdoor fan motor stops, the load current point P will appear to be higher than the set value by a predetermined value.
This allows a time margin of Δt, and the frequency of the second-stage current release, which switches the indoor fan to high strength, can be significantly reduced by this margin of time Δt.

[Brief explanation of drawings]

FIG. 1 is a flowchart for explaining the operation of an embodiment of the present invention, FIG. 2 is a connection diagram showing the relationship between the refrigeration cycle and the control device in an embodiment of the present invention, and FIG. FIG. 4 is a flowchart for explaining the operation of another embodiment of the present invention,
FIG. 5 is a wiring diagram showing the relationship between a refrigeration cycle and a control device according to another embodiment of the present invention, FIG. 6 is a flowchart for explaining the operation of the embodiment of FIG. 5, and FIG. 7 is a diagram of the present invention. 1 is a system diagram showing an example of the configuration of a typical refrigeration cycle of a heat pump type air conditioner to which the refrigeration cycle is applied. 1...Compressor, IM...Compressor motor, 3...Indoor heat exchanger, 3F...Indoor fan, 3M
...Indoor fan motor, 5...Outdoor heat exchanger, 5F
...Outdoor fan, 3M...Outdoor fan motor, 10
...control device, 1.2a, 12b, 12c, 13. '
J-4-7. Switch, 15.17...Current detector, 1
6... Room temperature sensor, IC... Compressor motor current, I. ...Outdoor fan motor current, ■...Total current, II...[First setting value, ■2...Second setting value, I3...Third setting value, ■4. ...Fourth set value, Δ■...Additional set value.

Claims (1)

[Claims] Composed of a compressor, an indoor heat exchanger that has at least an indoor fan that can be switched between strong-wind operation and weak-wind operation and functions as a radiator, and an outdoor heat exchanger that has an outdoor fan and functions as a heat sink. The compressor, the indoor fan, and the outdoor fan are driven by a compressor motor, an indoor fan motor, and an outdoor fan motor, respectively, so as to reduce the deviation between the detected temperature of the room to be heated and the set temperature to zero. A control device for a heat pump air conditioner that controls each of the motors according to a predetermined program includes: current detection means for detecting the current of the compressor motor; and a relatively large second set value, and as the current detected by the current detection means increases, the value obtained by adding a predetermined value to the current is set as the first step. When the first set value is reached, the outdoor fan motor is stopped, and despite the stop of the outdoor fan motor, the current of the compressor motor further increases and when the second set value is reached, the indoor fan A control device for a heat pump type air conditioner, characterized in that it is equipped with a control means for forcibly switching the heat pump type air conditioner to strong wind operation.