JP2543274B2 - Control device for air conditioner - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an air conditioner equipped with an inverter device for controlling the operating frequency of an outdoor fan.

[0002]

2. Description of the Related Art In recent years, a large number of air conditioner control devices using an inverter device for varying the frequency of a power source have been used. As a conventional technique, for example, JP-A-61
There is one disclosed in Japanese Patent No. 128055.

An example of the control device for the air conditioner described above will be described below with reference to the drawings. FIG. 4 is a schematic configuration diagram of a control device for a conventional air conditioner, FIG. 5 is an operation flowchart thereof, and FIG. 6 is a characteristic diagram showing a change over time of the suction temperature of the compressor and an outdoor fan operating state.

In FIG. 4, 1 is a compressor, 2 is a four-way valve,
Reference numeral 3 is an indoor heat exchanger, 4 is a pressure reducing device, and 5 is an outdoor heat exchanger, and these are connected in a ring to form a refrigeration circuit. Reference numeral 6 denotes an indoor unit, which is operation command means 7 for determining operation / stop of the air conditioner, indoor control means 8 for determining operation / stop of the indoor fan based on a signal S1 from the operation command means 7,
The indoor fan 9 is turned on and off by a signal S2 from the indoor control means 8.

Reference numeral 10 is an outdoor unit. The outdoor control means 11 is connected via the signal line S1 of the operation command means 7 and the signal line S2 of the indoor control means 8, and the signal line S3 of the outdoor control means 11 connects the compressor 1 to the commercial AC power supply 13. It is connected to the electromagnetic contactor 12 for the compressor which connects and disconnects.

The signal line S4 from the outdoor control means 11 is used to turn on and off the outdoor fan 14 so that the commercial AC power supply 1 is provided.
Magnetic contactor for outdoor fan 15 that connects and disconnects 3
It is connected to the.

A temperature sensor 16 is attached to the low pressure portion of the compressor 1. The signal line S5 of the temperature sensor 16 has a temperature Tc.
The intake temperature Tc detected by the temperature detecting means 17 is connected to the temperature detecting means 17 for detecting the temperature of the intake air.
Through the signal line S7 to the outdoor control means 11.

The operation of the conventional air conditioner control device configured as described above will be described below with reference to FIGS. 5 and 6.

In FIG. 5, first, in step 1, if the operation command means 7 is in the stopped state, step 1 is repeated, and if it is in the operation state, the indoor control means 8 turns on the indoor fan 9 from the signal S1 and the signal line. The operation is commanded to the outdoor control means 11 from S2.

Accordingly, the outdoor control means 11 causes the signal S
3, the electromagnetic contactor 12 for the compressor is connected, and the commercial AC power supply 13 is supplied to the compressor 1 to operate.

Further, the outdoor control means 11 connects the outdoor fan electromagnetic contactor 15 by the signal S4, supplies the power of the commercial AC power source 13 to the outdoor fan 14, turns on the outdoor fan 14, and turns on the air conditioner. Put into operation.

Next, in step 2, the operating condition of the outdoor fan 14 is turned on and off according to the capacity of the air conditioner.
The outdoor control means 11 determines whether the outdoor fan 1 is connected or disconnected from the electromagnetic contactor 15 for the outdoor fan through the signal line S4.
Turn ON / OFF the operation state of 4.

Next, the operation of steps 3 to 5 will be described with reference to FIG. In step 3, the signal line S of the temperature sensor 16
5, the temperature detecting means 17 detects the suction temperature Tc.

In step 4, the detected temperature determination means 18 compares the intake temperature Tc detected by the temperature detection means 17 with the intake temperature lower limit value Tmin, and if the intake temperature Tc is larger, the step 2
Then, the normal operation of controlling the outdoor fan 14 is performed in accordance with the capacity based on the indoor pressure and the like.

Intake temperature Tc detected by the temperature detecting means 17
However, if it is smaller than the lower limit of the intake temperature Tmin, the intake temperature becomes abnormal and the low pressure drop causes the indoor heat exchanger 3 to freeze, causing the system to stop. At step 5, the outdoor fan 14 is forcibly turned off. To do. In this case s
Returning to step 3, that is, as shown in FIG. 6, when the outdoor fan 14 is in the ON state for securing the capacity for T0 and T1 hours, the intake temperature Tc drops and exceeds Tmin due to the change in the outside air temperature at T1, so that the outdoor The fan 14 is forcibly set to the operation 0FF state and the intake temperature Tc is raised. Also, at T2, Tmin
Since the suction temperature Tc has risen as described above, the outdoor fan 14 is turned on again to secure the capability. The same operation is repeated at T3 and T4.

[0016]

However, in the above-mentioned conventional configuration, the intake temperature lower limit value must be set high in order to take into account the overshoot of the intake temperature at the time of low outside air temperature of cooling, so that the system performance is low. Cannot be fully utilized.
Further, due to the repeated operation / stop of the outdoor fan 14, there is a variation in performance, which causes an uncomfortable operating state for people due to uneven cooling, and finally the indoor heat exchanger 3 may freeze.

Further, when the intake temperature cannot be raised by only the outdoor fan 14, the compressor is operated / stopped to increase the power consumption of the system.

In view of the above problems, the present invention can accurately set the lower limit value of the intake temperature at the time of cooling low outside air temperature to the limit so that the capacity of the system can be fully utilized by the detection by the temperature, and the outdoor fan and the compressor. It is an object of the present invention to provide a control device for an air conditioner that significantly reduces the frequency of operation and stoppage, suppresses cooling unevenness, provides a comfortable operating state for people, and reduces system power consumption.

[0019]

In order to achieve this object, a control device for an air conditioner according to the present invention comprises a frequency command means for determining an operating frequency of an outdoor fan based on a signal from the outdoor control means, and the frequency command. Inverter control means for varying the operating frequency of the outdoor fan from the operating frequency from the means, a temperature sensor attached to the low pressure part of the compressor, a temperature detecting means for detecting the intake temperature from the signal of the temperature sensor, and the temperature Correction for correcting the operating frequency of the outdoor fan based on the detection temperature prediction means that predicts the next intake temperature from the previous intake temperature and the current intake temperature detected by the detection means, and the intake temperature lower limit value that is the limit of the next intake temperature and the intake temperature. The outdoor unit is provided with a detected temperature determining means for calculating a frequency and transmitting a correction frequency to the frequency commanding means.

[0020]

With this configuration, when the next intake temperature of the detected temperature predicting means is below the intake temperature lower limit value during operation of the compressor,
The detected temperature determination means transmits the correction frequency to the frequency command means to change the operating frequency of the outdoor fan.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An air conditioner control apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a control device for an air conditioner in one embodiment of the present invention. FIG. 2 is a flow chart of the operation, and FIG. 3 is a characteristic diagram showing the change over time of the intake temperature of the outdoor fan and the operating state of the outdoor fan.

In FIG. 1, 1 is a compressor, 2 is a four-way valve,
Reference numeral 3 is an indoor heat exchanger, 4 is a pressure reducing device, and 5 is an outdoor heat exchanger, and these are connected in a ring to form a refrigeration circuit.

Reference numeral 6 denotes an indoor unit, which is operation command means 7 for determining whether the air conditioner is operated or stopped, indoor control means 8 for determining operation or stop of the indoor fan based on the signal S1 from the operation command means 7, and indoor control means. ON, OF from signal S2 from 8
It is composed of an indoor fan 9 for performing F.

Reference numeral 10 is an outdoor unit. The outdoor control means 11 is connected to the signal line S1 of the operation command means 7 via the transmission line S2 of the indoor control means 8, and the signal line S3 of the outdoor control means 11 connects the compressor 1 to the commercial AC power supply 13. It is connected to the electromagnetic contactor 12 for the compressor which connects and disconnects.

A signal line S8 from the outdoor control means 11 is connected to a frequency command means 19 for determining an operating frequency so that the outdoor fan 14 is controlled by an inverter so as to perform variable operation frequency control. The signal line S9 of the frequency command means 19 is connected to the signal line S9. It is connected to the outdoor fan 14 via the inverter control means 20. Further, the inverter control means 20 is connected to the commercial AC power supply 13 via the compressor magnetic contactor 12.

A temperature sensor 16 is attached to the low pressure portion of the compressor 6. The signal line S5 of the temperature sensor 16 is connected to the temperature detecting means 17 for detecting the intake temperature Tc, and the intake temperature Tc detected by the intake temperature detecting means 17 is changed from the previous intake temperature and the next intake temperature to the next intake temperature by the signal S10. Through the detected temperature predicting means 21 for predicting, the next intake temperature and the intake temperature lower limit value Tm from the signal line S11 which is the next intake temperature.
It is connected to the detected temperature determining means 18 which compares in and calculates a correction frequency.

The correction frequency signal line S12 from the detected temperature determining means 18 is connected to the frequency commanding means 19,
The operating frequency of the outdoor fan 14 is calculated and determined from the operating frequency during normal control and the correction frequency.

The operation of the control device for an air conditioner configured as described above will be described below with reference to FIGS. 2 and 3.

In FIG. 2, first, if the operation command means 7 is stopped in step 1, step 1 is repeated, and if it is in operation, the indoor control means 8 turns on the indoor fan 9 from the signal S1 and the transmission line. The operation is commanded to the outdoor control means 11 from S2.

Accordingly, the outdoor control means 11 causes the signal S
3, the electromagnetic contactor 12 for the compressor is connected, the commercial AC power source 13 is supplied to the compressor 1, and the signal S8 sends the signal S8 for starting the operation to the frequency command means 19.

The frequency command means 19 determines the operating frequency of the outdoor fan 14 according to the capacity required for the system from the pressure inside the room and the like, and the inverter control means 20 receives the signal S9.
The operating frequency is sent via. Inverter control means 20
Then, the inverter output waveform corresponding to the required operating frequency is generated, the outdoor fan 14 is operated, and the air conditioner is brought into an operating state.

Next, in step 2, the frequency command means 1
At 9, the operating frequency of the outdoor fan 14 is determined according to the capacity required for the system from the pressure inside the room, and the operating frequency is sent to the inverter control means 20 via the signal S9.
The inverter control means 20 generates an inverter output waveform according to the required operating frequency, operates the outdoor fan 14, and changes the operating frequency of the outdoor fan 14 according to the capacity of the air conditioner.

Next, the operation of steps 3 to 5 will be described with reference to FIG. In step 3, the signal S5 from the temperature sensor 16
The temperature detector 17 detects the suction temperature Tc.

When assuming that the intake temperature detected at the previous time t1 is the intake temperature tc1 at the previous time and the intake temperature detected at the current time t2 is the intake temperature tc2 at the present time, step 4 is calculated as follows by the following (Equation 1) and (Equation 2). Intake temperature tc3 at t3
Is calculated.

[0036]

[Equation 1] α = (tc1-tc2) / (t1-t2)

[0037]

[Equation 2] tc3 = α * t3 + tc1-α * t1

In step 5, in the detected temperature determination means 18, the next intake temperature tc calculated by the detected temperature prediction means 21.
If 3 is larger than the lower limit value Tmin of the intake temperature, if it is larger, it moves to step 2, and the normal operation of controlling the outdoor fan 14 is performed according to the capability.

If the next intake temperature t3 calculated by the detected temperature predicting means 21 is smaller than the intake temperature lower limit value Tmin, if the intake temperature is small, an abnormal intake temperature is predicted, and the system is stopped due to freezing of the indoor heat exchanger due to a drop in low pressure. Since it can be predicted that this will occur, the correction frequency f is calculated by the following (Equation 3) in order to reduce the operating frequency of the outdoor fan 14 at step 6,
2 to the frequency command means 19.

[0040]

[Equation 3] f = (Tmin-tc3) * k k: constant

Next, at step 7, the frequency command means 19 subtracts the correction frequency f from the current operating frequency of the outdoor fan and sends the operating frequency to the inverter control means 20 via the signal S9 to drive the outdoor fan 14 to a desired operation. Drop to frequency. In this case, the process returns to step 3. Below T2, T3
Similarly at T4, the next intake temperature is controlled while being predicted from the previous intake temperature and the current intake temperature.

That is, as a specific example of (Equation 1), (Equation 2), (Equation 3), when the outdoor fan 14 is operating at F1 for T0 and T1 from FIG. , The intake temperature drops, and when the intake temperature is Tc1 and T2,
When Tc2 is detected by the temperature detection means 17, the detection prediction means 21 calculates the intake temperature Tc3 at T3 from (Equation 1) and (Equation 2). Since Tc3 is larger than Tmin, the outdoor fan 14 is operated by normal control.

At the next timing, when the temperature detecting means 17 detects Tc3 when the intake temperature is Tc2 and T3 due to a change in the outside air temperature at T2, the detected temperature predicting means 21.
Then, the intake temperature Tc4 at the time T4 is calculated from the equations (1) and (2). Since Tc4 becomes smaller than Tmin, it can be predicted that the trajectory of the dotted line will be drawn as shown in FIG. 3 at T4, and it is considered that the suction temperature abnormality occurs.

Therefore, from (Equation 3), the correction frequency FH for reducing the operating frequency of the outdoor fan is calculated from Tc4 and Tmin in order to avoid the abnormal intake temperature, and is sent to the frequency command means 19 via the signal S12.

The frequency command means 19 requests the operating frequency F2 from the inverter control means 20 in order to operate at the operating frequency F2 obtained by subtracting the correction frequency FH from the current operating frequency F1 of the outdoor fan. In order to change to the operating frequency F2, the intake temperature Tc can be controlled without causing overshoot with respect to Tmin at T4 as shown in FIG.

As described above, this embodiment is the outdoor control means 1
Frequency command means 19 for determining the operating frequency of the outdoor fan 14 based on the signal from the inverter 1, inverter control means 20 for varying the operating frequency of the outdoor fan 14 based on the operating frequency from the frequency command means 19, and the compressor 1. The temperature sensor 16 attached to the low pressure portion, the temperature detecting means 17 for detecting the intake temperature from the signal of the temperature sensor 16, the previous intake temperature detected by the temperature detecting means 17, and the next intake temperature is predicted from the present intake temperature. Detected temperature predicting means 21
And a detection temperature determining means 18 for calculating a correction frequency for correcting the operating frequency of the outdoor fan 14 from the next intake temperature and the lower limit value of the intake temperature, which is the limit of the intake temperature, and transmitting the correction frequency to the frequency command means 19. Is provided in the outdoor unit 10.

With this configuration, when the next intake temperature of the detected temperature predicting means 21 is lower than the lower limit of the intake temperature during the operation of the compressor, the detected temperature determining means 18 sends the correction frequency to the frequency commanding means, and the outdoor fan 14 is operated. In order to change the operating frequency of, the intake air temperature lower limit value at the time of cooling low outside air temperature can be accurately set up to the limit so that the system capacity can be fully utilized by temperature detection, and the operation of the outdoor fan and compressor, It is possible to significantly reduce the frequency of stoppages, suppress uneven cooling, provide a comfortable operating state for people, prevent freezing of the indoor heat exchanger, and reduce power consumption of the system.

[0048]

As described above, according to the present invention, the frequency command means for determining the operating frequency of the outdoor fan based on the signal from the outdoor control means, and the operating frequency of the outdoor fan can be varied from the operating frequency from the frequency command means. Inverter control means, detection temperature prediction means that predicts the next intake temperature from the previous intake temperature detected by the temperature detection means, and the current intake temperature, and the outdoor fan from the intake temperature lower limit value that is the limit of the next intake temperature and the intake temperature. It is provided with the detected temperature determining means for calculating the correction frequency for correcting the operating frequency and transmitting the correction frequency to the frequency command means, and the outdoor unit.

During the operation of the compressor, if the next intake temperature of the detected temperature predicting means is below the lower limit of the intake temperature, the detected temperature determining means sends the correction frequency to the frequency command means to change the operating frequency of the outdoor fan. Of.

Therefore, the lower limit value of the intake temperature at the time of cooling low outside air temperature can be accurately set to the limit so that the capacity of the system can be fully utilized by the detection by the temperature, and the frequency of operating and stopping the outdoor fan and the compressor can be set. It is possible to realize an excellent air conditioner control device that can significantly reduce cooling unevenness, provide comfortable operating conditions for people, prevent freezing of the indoor heat exchanger, and reduce system power consumption. It is a thing.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a control device for an air conditioner according to an embodiment of the present invention.

FIG. 2 is an operation flowchart for explaining the operation of the control device for the air conditioner in the embodiment.

FIG. 3 is a characteristic diagram showing changes over time in the intake temperature of the outdoor fan of the control device for the air conditioner and the operating condition of the outdoor fan in the embodiment.

FIG. 4 is a schematic configuration diagram of a conventional air conditioner control device.

FIG. 5 is an operation flowchart illustrating an operation of a conventional air conditioner control device.

FIG. 6 is a characteristic diagram showing changes over time in the intake temperature of the outdoor fan of the conventional air conditioner control device and the outdoor fan operating state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 6 Indoor unit 7 Operation command means 8 Indoor control means 9 Indoor fan 10 Outdoor unit 11 Outdoor control means 12 Magnetic contactor for compressor 13 Commercial AC power supply 14 Outdoor fan 16 Temperature sensor 17 Temperature detection means 18 Detected temperature determination means 19 frequency command means 20 inverter control means 21 sensed temperature prediction means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ichiro Sugioka 3-22 Takaidahondori, Higashi-Osaka City, Osaka Prefecture Matsushita Refrigerator Co., Ltd. (72) Toshio Mamiya 3-22 Takaidahondori, East Osaka, Osaka Matsushita Refrigerating Machinery Co., Ltd. (56) Reference JP-A-2-64342 (JP, A) Actual development Sho 55-162074 (JP, U)

Claims (1)

(57) [Claims] 1. An indoor unit comprising an operation command means for deciding whether to start or stop operation of an air conditioner, and an indoor control means for deciding whether to start or stop operation of an indoor fan according to a signal from the operation command means, The outdoor control means connected via the signal line of the operation command means and the signal line of the indoor control means, and the electromagnetic contact for the compressor which connects and disconnects the commercial AC power source to the compressor by the signal of the outdoor control means. And a frequency command means for determining the operating frequency of the outdoor fan based on a signal from the outdoor control means, an inverter control means for varying the operating frequency of the outdoor fan from the operating frequency from the frequency command means, and the compressor. Temperature sensor attached to the low pressure part of the, the temperature detection means for detecting the intake temperature from the signal of the temperature sensor, the previous intake temperature detected by the temperature detection means, A detection temperature predicting unit that predicts the next intake temperature from the intake air temperature, and a correction frequency that corrects the operating frequency of the outdoor fan from the next intake temperature and the lower limit of the intake temperature that is the limit of the intake temperature, and the frequency command When the next intake temperature of the detected temperature predicting means exceeds the lower limit of the intake temperature during the operation of the compressor, the outdoor unit is composed of a detected temperature determining means for transmitting a correction frequency to the means.
The control device for an air conditioner, wherein the detected temperature determination means transmits a correction frequency to the frequency command means to change the operating frequency of the outdoor fan.