JPH0384350A - Air conditioner - Google Patents

Abstract

PURPOSE:To enable maximization of capacity of a compressor during limitation of current capacity of a source plug socket by providing a threshold decreasing means to output a signal by means of which a threshold on the outdoor machine side is decrease and a threshold increasing means to output a signal by means of which a threshold on the outdoor machine side is increased. CONSTITUTION:Since, when the number of revolutions of an indoor blower 3 is high (when an indoor blower current Ifi is high), the temperature of a heater 2 is low and a heater current Ih is high, a current Ic of a compressor 7 is limited to a lower value by means of a threshold decreasing means 9, and a threshold Nh of an outdoor machine 6 is set to a low value. Reversely, since, when the number of revolutions of the indoor blower 3 is low (when Ifi is low), the temperature of the heater 2 is high and the heater current Ih is low, a threshold Nl of an outdoor machine 6 is set to a high value by means of a threshold increasing means 10, and the current Ic of the compressor 7 is allowable up to a high value. Thus, the heater 2 having a self-current limiting function is used as an auxiliary heating heater, and during limitation of current capacity of a source plug socket, capacity of the compressor 7 can be maximized.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an air conditioner for adjusting the temperature, humidity, etc. of indoor air.

<Prior art> Heaters conventionally used as auxiliary heating means in air conditioners to adjust the temperature and humidity of indoor air are called nichrome heaters and sheathed heaters. However, after that, it shows constant current characteristics.

This heater is arranged on the indoor unit side, and is controlled to be continuously energized during heating operation when the paheater is turned on, or to be energized intermittently by a bimetal thermometer or the like.

On the other hand, air conditioners require peak current control of the outdoor unit (especially the compressor) due to the current capacity of the power outlet used (household outlets (typically 15A)).
During the above-mentioned heating operation with the heater on, a method was adopted in which a threshold value for peak current control was applied by unconditionally subtracting the heater current consumed by the indoor unit, regardless of the air volume of the indoor blower, etc. .

Problems to be Solved by the Invention 〉 However, due to recent advances in ceramic processing technology, ceramic heaters (hereinafter referred to as PTC heaters) whose internal resistance exhibits positive temperature characteristics, that is, have a self-current limiting function, have become popular. However, it has also come to be used as an auxiliary heater for air conditioners. This is because the PTC heater has a self-current limiting function, so even if it is continuously energized, there will be no disconnection failure due to overheating, and there is an advantage that control parts such as bimetal are not required.

On the other hand, an air conditioner that can perform rapid heating or high-temperature blow-out heating by maximizing the ability of the compressor (by passing current through the compressor) within the constraints of the current capacity of the power outlet. is still in demand.

Now, considering the temperature characteristics of the PTC heater, since its internal resistance exhibits positive temperature characteristics, the relationship between heater current and temperature becomes negative characteristics as shown in FIG. Also, P
'The temperature of the FC heater has a characteristic that changes depending on the heat exchange air volume from the indoor blower (ie, the rotation speed of the indoor blower). In other words, the higher the rotation speed of the indoor fan, the lower the heater temperature (lower, and the larger the heater current (H in Figure 6.7). Conversely, the lower the rotation speed of the indoor fan, the higher the heater temperature and the smaller the heater current. (Figure 6.7).

In this way, the heater current of the PTC heater changes depending on the air volume of the indoor blower. Therefore, when a PTC heater is used in an air conditioner as an auxiliary heating heater, the threshold for peak current control of the outdoor unit is unconditionally set to the heater current calculated in advance from the heater's rated power, as in the past. If you decide by subtracting
When the heater current decreases due to the air volume of the indoor fan, that amount of current is not being used effectively, and it is not possible to effectively use the current capacity of the power outlet to maximize the compressor's performance. There wasn't.

In view of the above, the present invention maximizes the ability of a compressor within the constraints of the current capacity of a power outlet when a heater with a self-current limiting function such as a PTC heater is used as an auxiliary heating means. The purpose is to provide an air conditioner that can.

<Means for Solving the Problems> The means for solving the problems according to claim 1 of the present invention, as shown in FIGS. Indoor blower 3 and the heater 2
and an operation section 4 for selecting an operation mode of the indoor blower 3, and an indoor control section 5 for driving and controlling the heater 2 and the outdoor unit 6 based on an output signal from the operation section 4.
In an air conditioner equipped with an outdoor controller 8 on the side that changes the peak current control threshold of the outdoor unit 6 in accordance with an output signal from the indoor controller 5, the indoor controller 5 is operated. Threshold reducing means 9 outputs a signal for reducing the threshold to the outdoor unit 6 based on the drive signal for the heater 2 and the rotation speed increase signal for the indoor blower 3 from the unit 4; and the drive signal for the heater 2. and a threshold increasing means 10 for outputting a signal for increasing the threshold to the outdoor unit G based on a signal for decreasing the rotational speed of the indoor blower 3.

In the second aspect, the indoor side control section 5 is configured to control the outdoor unit 6 based on the drive signal for the heater 2 and the air volume control signal for the indoor blower 3 from the operation section 4 before outputting the rotation speed increase signal for the indoor blower 3.
Threshold reducing means 9 outputs a signal to decrease the threshold to the side, and threshold increasing means outputs a signal to increase the threshold to the outdoor unit 6 after outputting the signal to decrease the rotational speed of the indoor fan 3. Means 10 is provided.

In the problem-solving means according to claim 1, the indoor control section 5 determines the settings of cooling operation, dehumidification operation, "heater on" heating operation, and "heater on" based on the settings of the operation section 4 and the output of the room temperature detector 14. The indoor blower 3, the heater 2, and the outdoor controller 8 are operated by selecting one of the operating modes of "off" and "heating operation" and the air volume of the indoor blower.

Here, the current capacity of the power outlet is Id, and the total current of the indoor unit is 11. If the total current of the outdoor unit is Io, Id≧I
Must be i+Io. Furthermore, l1=Ifi+
Ih-1-Isi I o= I c+ I fo ten T s.

(However, I fi: indoor blower current, h: heater current, Isi/indoor control section current, IC1 compressor current, I
f'.

Assuming outdoor blower current, Iso: outdoor control unit current), Id≧I h+ I fi+ I si+ I c+
I fo + I s.

becomes. Typically, Isi and Iso have low current consumption, and I
fi and Ifo indicate stable current values according to the selected air volume. On the other hand, as shown in FIG. 7, the heater current Ih exhibits a larger value as the indoor air flow rate increases. In other words, when the rotational speed of the indoor fan 3 is high (when Ifi is large), the temperature of the heater 2 is low and the heater current Ih is large, so the threshold reduction means 9 reduces the current Ic of the compressor 7 to a low value. Therefore, the threshold value Nh of the outdoor unit 6 is set to a low value.

Conversely, when the rotational speed of the indoor fan 3 is low (when Ifi is small), the temperature of the heater 2 is high and the heater current Ih is small, so the threshold value Nl of the outdoor unit 6 is high by the threshold increasing means IO. The current Ic of the compressor 7 is allowed up to a high value.

Therefore, the heater 2 having a self-current limiting function can be used as an auxiliary heater, and the capacity of the compressor 7 can be maximized within the constraints of the current capacity of the power outlet.

According to claim 2, the indoor fan 3 is set to "low" from the operation unit 4.
Assume that a setting for switching to the air volume is input to the indoor control unit 5. The indoor controller 5 switches the indoor fan 3 to a "low" air volume using the threshold increasing means IO (tl in FIG. 4).
), the temperature of the heater 2 increases and the heater current decreases and becomes stable (t2 in FIG. 4). The indoor control section 5 moves from tl to t.
During period 2, a serial signal is sent to the outdoor controller 8 to switch the threshold of the outdoor unit 6 from Nh to Nl.

Next, it is assumed that a setting for switching the indoor air blower 4fi3 to a "strong" air volume is input from the operation unit 4 to the indoor control unit 5 (t3 in FIG. 4). The indoor side control unit 5 immediately turns on the indoor blower 3.
If the airflow rate is switched to "strong", the temperature of the heater 2 will drop and the heater current will increase, Id<Ii+Io, and an overcurrent will flow through the air conditioner. In order to prevent this, when the indoor control section 5 receives a request from the operation section 4 to switch to the "high" air volume by the threshold reduction means 9, it first sends a serial signal to the outdoor control section 8, and from t3 The threshold value of the outdoor unit 6 is switched from N1 to Nh during the period t4. Then, the indoor controller 5 switches the indoor blower 3 to the "strong" air volume (14 in FIG. 4). Then, the temperature of the heater 2 decreases, and the heater current increases and becomes stable (t5 in Fig. 4), but since the threshold value is first switched to Nh and the outdoor current is suppressed, Id≧I.
i+Eo, and the total current of the air conditioner does not exceed the current capacity of the power outlet.

Therefore, a heater with a self-current limiting function is used as an auxiliary heater, allowing the compressor's current to the maximum within the current capacity of the power outlet. It is possible to prevent the air conditioner from activating, and to realize an air conditioner that is capable of faster heating operation and higher temperature blowing operation.

<Example> Hereinafter, an example of the present invention will be described based on the drawings. 1st
The figure is a functional block diagram of an air conditioner showing an embodiment of the present invention, Fig. 2 is a control block diagram, Fig. 3 is a control circuit diagram, and Fig. 4 shows the heater current and the threshold value of the current detection section. It is a figure showing the relationship with the timing of switching.

As shown in the figure, the air conditioner of the present invention includes, on the indoor unit 1 side, a PTC heater 2 having a self-current limiting function, and an indoor blower 3 having a two-speed air volume switching tap capable of switching the air volume.
, an operation section 4 for selecting the operation mode of the heater 2 and the indoor blower 3, and an indoor control section 5 for driving and controlling the heater 2 and the outdoor unit 6 based on output signals from the operation section 4, A three-phase electric compressor 7 that compresses the refrigerant limb, and an outdoor controller 8 that changes the peak current control threshold of the outdoor unit 6 in accordance with the output signal from the indoor controller 5 are installed on the 6 side. In preparation, the indoor side control section 5 is provided with a signal to the outdoor unit 6 based on a drive signal for the heater 2 and an air volume control signal for the indoor blower 3 from the operation section 4 before outputting a signal to increase the rotation speed of the indoor blower 3. Threshold reducing means 9 outputs a signal for decreasing the threshold; Threshold increasing means 10 outputs a signal for increasing the threshold to the outdoor unit 6 after outputting the signal for decreasing the rotational speed of the indoor blower 3. was established ().

As shown in Fig. 2.3, a DC low-voltage power supply circuit I3, an indoor blower 3, and a heater 2 are connected to the indoor power supply line a1 connected to the commercial power supply It via an overcurrent 18i-protection fuse 12. ing.

The indoor control section 5 is composed of a one-step microcomputer (hereinafter referred to as microcomputer), and a power terminal P1 is connected to the operation section 4, and a P2L1 room temperature detector 1 is connected to the control section 4.
4, and the output terminal Q1. Q2 is connected to the indoor blower 3 via the air volume control section 15, the output terminal Q3 is connected to the PTC heater 2 via the heater drive section 16, and the output terminals Sl and S2 are connected to the outdoor control section 8.

The air volume control unit 15 includes a blower relay try, <17
A strong wind relay I8 is connected to the Ql output side, and a weak wind relay 19 is connected to the Q2 output side. Further, the heater drive section 16 includes a heater relay driver 20 and a heater relay 21.

The Kiuchi control unit 5 receives power from the DC low-voltage 7R wholesale circuit 13, inputs the manual setting signal from the operation unit 4 and the room temperature signal from the room temperature detector 14 from the PI and P2 input terminals, and programmed ROM, data RA
According to the logical operation result using M (both not shown), select one of the following modes: cooling operation, dehumidification operation, "heater on" heating operation, "heater off" heating operation, and output the corresponding output signal. It is sent from the output terminal Q1.02 to the blower relay driver 17, from Q3 to the heater relay driver 20, and from Sl and S2 to the outdoor controller 8.

When the Q1 output becomes "H", the strong wind relay 18 is closed and the "strong" tap winding of the indoor blower 3 is energized to rotate "strong". When the Q2 output becomes "H", the weak wind relay 19 closes and "weak" tap winding'! fAt2 is energized and rotates "weakly". When the Q3 output becomes "I-I", the heater relay 21 is closed and the PTC heater 2 is energized.

The outdoor unit 6 includes the outdoor controller 8, a compressor 7,
It includes an outdoor blower 22 and an outdoor current detection circuit 23, and the indoor unit 1 and the outdoor unit 6 are connected by two power lines and two serial signal lines.

The outdoor control section 8 is composed of a microcomputer, and has an input terminal S.
ll and S12 are connected to the output terminals Sl and S2 of the indoor control section 5, and the norial signals from the Sl and S2 outputs are input. Moreover, the input terminal pH is the outdoor current detection circuit 23? In this connection, the detection circuit 23 is composed of a current transformer 24 and a current detection section 25.

The output terminal Qll of the outdoor controller 8 is connected to the relay driver 2
6. It is connected to the outdoor blower 22 via a relay 27, and the output terminals Q+2 to Q]7 are connected to the compressor 7 via a drive circuit 28.

The drive circuit 28 includes an inverter drive unit 29 and a three-phase inverter power supply circuit 30 consisting of six power transistors.
It consists of

The relay driver 26 and the inverter are controlled according to the logical operation results using the pre-programmed ROM and data RAM (both not shown) in accordance with the norial signal from the indoor controller 5 and the input from the current detector 25. Signals are sent to the drive section 29 from output terminals Q11 and Q12 to QI7.

A Karen lance 24, a DC low voltage power supply circuit 31, an outdoor blower 22, and a rectifier circuit 32 are connected to the outdoor power line. The outdoor controller 8 is supplied with power from the DC low-voltage power supply circuit 31, and the current transformer 24 converts the AC current for the outdoor unit into a voltage signal, and the current detector 25 compares the result with a predetermined threshold value and sends the result to the indoor controller. pH of outer control section 8
Input to input terminal.

Further, when the Qll output becomes "H", the relay 27 is closed and the outdoor blower 22 is energized. Then, the inverter drive unit 29 is driven by the Q12 to Q17 outputs of the outdoor side control unit 8.
The three-phase inverter power supply circuit 30 performs PWM control on the three-phase electric compressor 7 in accordance with six drive signals output by the three-phase electric compressor 7. Dej of output pulses from output terminals Q12 to Q17,
-T and the frequency determine the frequency "f" and voltage "V" of the inverter waveform applied to the three-phase electric compressor 7.

Since the square of V/f is proportional to the torque of the three-phase electric compressor 7, the ratio of V/f is controlled to be constant.

During operation, the current Ic of the three-phase electric compressor 7 fluctuates due to various factors. When the outside air temperature of the outdoor unit is very high during heating operation and cooling operation, the discharge pressure of the three-phase electric compressor 7 increases, resulting in an overload state, and the AC current of the three-phase electric compressor 7 increases.

In addition, if the outside temperature is very low during heating operation, the refrigerant enters the cylinder in a liquid state during startup, resulting in a so-called "liquid trap" state in which the cylinder and rotor are locked, and the AC of the three-phase electric compressor 7 is Current increases. This "liquid-filled" condition disappears when the compressor temperature rises and the refrigerant begins to circulate. Furthermore, when the power supply voltage decreases, the AC current increases due to the inertia of the three-phase electric compressor 7 to continue rotating at the same speed as before.

The current detection unit 25 detects the AC current fluctuation via the current transformer 24, and if the peak current exceeds a predetermined threshold, a signal to suppress the frequency and voltage of the inverter waveform is fed back to the outdoor control unit 8. are doing.

At the bottom of the tank, the indoor control section 5 selects one of the following modes: cooling operation, dehumidification operation, heating operation with "heater on", or heating operation with "heater off", based on the settings of the operation section 4 and the output of the room temperature detector 14. After selecting the operation mode and the air volume of the indoor blower, the air volume control section 15. A signal is sent to the heater drive section 16 and the outdoor control section 8. According to the signal, the air volume control section 15 operates the indoor blower 3, and the heater drive section 16 operates the PTC heater 2. Then, the outdoor controller 8 operates the compressor 7 through the drive circuit 28,
At the same time, the outdoor blower 22 is activated.

Here, if the current capacity of the power outlet is Id, the total current of the indoor unit is Ii, and the total current of the outdoor unit is Io, then I'd≧
It must be Ii+Io. Furthermore, 1i=tri
+rh+ l5i IO= r c+ I fo+ I s.

(However, I fi: indoor blower current, Ih: heater current, r si: indoor control unit current, c: compressor current, I
fo・outdoor blower current, Iso: outdoor control section current), then Id≧I h+ I fi+ I si+ I c+
I fo + I s.

becomes. Typically, Isi and Iso have low current consumption, and I
fi and Ifo indicate stable current values according to the selected air volume. On the other hand, as shown in FIG. 7, Ih shows a larger value as the amount of air blown into the room increases. In other words, when the rotational speed of the indoor fan 3 is high (when Ifi is large), the temperature of the PTC heater 2 is low and ih is large, so the current Ic of the compressor 7 is limited to a low value, and the outdoor current detection circuit The threshold value of 23 is also set to a low value. Conversely, when the rotation speed of the indoor fan 3 is low (when Ifi is small), the PTC
Since the temperature of the heater 2 is high and Ih is small, the current 1c of the compressor 7 is allowed up to a high level, and the outdoor current detection circuit 23
The threshold is set to a high value. The threshold value of the outdoor current detection circuit 23 when the indoor fan 3 has a "strong" air volume is Nh,
Assuming that the threshold value at a "weak" air volume is Nl, it can be seen from the above that Nh<Nl.

Currently, the “heater” is in heating operation, the indoor fan is “strong”, and the room temperature is 2.
Assume that the setting is 0 degrees. When the Ql output and Q3 output of the indoor controller 5 are "H", the strong wind relay 18 and the heater relay 21 are closed, the indoor blower 3 is rotating "strongly", and the PTC heater 2 is energized. Since the indoor blower 3 is rotating at high speed, the temperature of the PTC heater 2 is low as described above, and the heater current is large as indicated by H in FIG. Therefore, the current detection unit 25 selects a low threshold value Nh. That is, the three-phase electric compressor 7 is operated at a room temperature of 20 degrees Celsius according to the control condition below the threshold value Nh. Room temperature information is inputted from the room temperature detector I4 to the indoor control unit 5, and is transmitted as a serial signal to the outdoor control unit 8. If the room temperature is less than the set value, the frequency and voltage of the inverter waveform are increased. If it reaches the setting, it is controlled to decrease.

Here, it is assumed that a setting for switching the indoor fan 3 to a "low" air volume is input from the operation unit 4 to the indoor control unit 5.

Then, the indoor control section 5 first sets the Q1 output to "L" and the Q2 output to "H" by the threshold increasing means 10, and switches the indoor fan 3 to a low air volume (tl in FIG. 4). The temperature of the PTC heater 2 increases and the heater current decreases and becomes stable (t2 in FIG. 4).
to t2, a serial signal is sent to the outdoor controller 8 to switch the threshold value of the current detector 25 from Nh to N1.

Next, from the operation unit 4, set the indoor fan 3 to “strong” air volume by 1;7.
The setting is inputted to the indoor control unit 5 (t3 in FIG. 4). In that case, the threshold value of the current detection section 25 is N1. At this time, in response to a request from the operation unit 4 to switch to the “strong” air temperature,
If the indoor blower 3 is switched to the "high" air volume through the air volume control unit 15 too soon, the temperature of the PTC heater 2 will drop and the heater current will increase, resulting in Id<Ii+Io
Suddenly, the overcurrent protection fuse 12 of the air conditioner blows out.

In order to prevent this, when the indoor side control section 5 receives a request from the operation section 4 to switch to "strong air volume," the threshold reduction means 9 first sends a normal signal to the outdoor side control section 8, and from t3 14, the threshold value of the current detection unit 25 is switched from Nl to Nh.Since the threshold value has been switched to Nh, which is lower than before, if the AC current 1c of the three-phase electric compressor 7 at that time is If the detection output exceeds the threshold value Nh, the current detection unit 25 outputs a suppression signal to the outdoor control unit 8, and as a result, the frequency and voltage of the inverter waveform decrease, and the three-phase electric voltage ]!I The AC current 1c of the compressor 7 decreases.

Then, the indoor control section 5 changes the Q2 output to "■7",
1 output to "H" and switch the indoor fan 3 to "high air volume" (t4 in Fig. 4). Then, the PTC heater 2
As the temperature decreases, the heater current increases and becomes stable (t5 in Figure 4), but first the threshold value switches to Nh,
Since the outdoor current is suppressed, it is suppressed so that rd≧Ii+To is satisfied, and the total current of the air conditioner does not exceed the current capacity of the power outlet.

Therefore, a PTC heater with a self-current limiting function is used as an auxiliary heating heater, and while allowing the compressor current to the maximum within the current capacity constraints of the power outlet, the current exceeds 7 when switching the air volume of the indoor blower. It is possible to prevent the protective fuse from operating, and it is possible to realize an air conditioner that is capable of faster heating operation and higher temperature blowing operation.

It should be noted that the present invention is not limited to the two-legged embodiment, and it goes without saying that many modifications and changes can be made to the above-described embodiment without departing from the scope of the present invention.

<Effects of the Invention> As is clear from the explanation in section 2 below, according to claim I of the present invention, there is an operation section on the indoor unit side for selecting the operation mode of the heater 43 and the indoor blower, and an output signal from the operation section is provided. an indoor control section that drives and controls the heater and the outdoor unit, and an outdoor control section that changes a peak current control threshold of the outdoor unit in accordance with an output signal from the indoor control section on the outdoor unit side. , a threshold value reducing means for outputting a signal to the indoor side control section to reduce the threshold value to the outdoor unit based on a heater drive signal and an indoor blower rotation speed increase signal from the operation section; and a heater drive. Since a threshold increasing means is provided which outputs a signal to increase the threshold to the outdoor unit based on the signal and the indoor fan rotation speed reduction signal, compression can be achieved within the current capacity constraints of the power outlet. You can make the most of your machine's capabilities.

According to claim 2, before outputting the rotation speed increase signal of the indoor blower, a signal for decreasing the threshold value is outputted to the outdoor unit side,
Since a signal to increase the threshold is output to the outdoor unit after the indoor blower rotation speed reduction signal is output, the overcurrent protection fuse is activated when the indoor blower air volume is switched, while allowing the maximum compressor current. This has excellent effects such as being able to prevent this from occurring and enabling more rapid heating operation and higher temperature blowing operation.

[Brief explanation of drawings]

Fig. 1 is a functional block diagram of an air conditioner showing an embodiment of the present invention, Fig. 2 is a control block diagram, Fig. 3 is a control circuit diagram, and Fig. 4 shows the heater current and the threshold of the current detection section. A diagram showing the relationship with the timing of value switching, Figure 5 is a current characteristic diagram of the PT'C heater, Figure 6 is a temperature-time characteristic diagram of the PTC heater, and Figure 7 is a current-temperature characteristic diagram of the PTC heater.
It is a time characteristic diagram. 1 Two indoor units, 2: Heater, 3: Indoor blower, 4: Operation unit, 5: Indoor control unit, 6: Outdoor unit, 8: Outdoor control unit,
9: Threshold reducing means; 10: Threshold increasing means. 3 Japanese Patent Application Publication No. 3 84350 (8) "-w mark 1 toe - w mark 1 toe - 4 colors 1 ζ - w mark mark 11

Claims (1)

[Claims] 1. A heater having a self-current limiting function on the indoor unit side;
The outdoor unit includes an indoor blower capable of switching air volume, an operation section for selecting an operation mode of the heater and the indoor blower, and an indoor control section for driving and controlling the heater and the outdoor unit based on an output signal from the operation section. In an air conditioner equipped with an outdoor controller that changes a peak current control threshold of the outdoor unit according to an output signal from the indoor controller,
a threshold value reducing means for outputting a signal to the indoor side control unit to reduce a threshold value to the outdoor unit based on a heater drive signal and an indoor blower rotation speed increase signal from the operation unit; 1. An air conditioner comprising threshold increasing means for outputting a signal for increasing a threshold to an outdoor unit based on a drive signal and an indoor fan rotation speed reduction signal. 2. The indoor control section according to claim 1, based on the heater drive signal and the indoor blower air volume control signal from the operation section,
Threshold reducing means for outputting a signal for reducing the threshold to the outdoor unit before outputting a signal for increasing the rotational speed of the indoor blower;
1. An air conditioner comprising threshold increasing means for outputting a signal for increasing a threshold to an outdoor unit after outputting a signal for decreasing the rotational speed of an indoor blower.