JP2661608B2 - Air conditioner fan control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fan control device for an air conditioner.

[0002]

2. Description of the Related Art In an air conditioner, when a blower motor for blowing air is locked and energized as it is,
In order to cause burnout of the motor or destruction of the current-carrying element, etc., the voltage applied to the motor and the current-carrying value are detected. If it is determined that the motor is locked, the power supply to the motor is stopped. Here, for example, in an air conditioner for a vehicle, the applied voltage to the blower motor is determined according to the setting of the air volume by the user and the like, and since a constant voltage is not applied to the motor, as shown in FIG. The reference current value for judging whether or not is locked is changed in accordance with the applied voltage. In general, the lower the applied voltage, the smaller the reference current value for the lock judgment.

[0003]

However, since the current supplied to the blower motor has a difference due to variations in the motor, the current-carrying elements, and the like, the detected currents are different in the normal operation and the normal operation. There is a variation as shown by the broken line in FIG. Further, since the reference current value for determining the lock is determined according to the voltage applied to the motor, when the voltage applied to the motor is low, the difference between the detected current value and the reference current value is small. For this reason, when the voltage applied to the motor is low, when the motor is not locked, there is a possibility that the lock may be erroneously determined to be locked, and as a result, an abnormal operation of the air conditioner such as a stop of the blower may be caused, A comfortable air-conditioning operation may not be ensured.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fan control device for an air conditioner that reliably detects a lock of a blower motor in an air conditioner and that does not hinder the blower operation due to detection of an erroneous lock. I do.

[0005]

SUMMARY OF THE INVENTION According to the present invention, there is provided a lock judging device for judging a lock of a motor (1) by detecting an applied voltage and an energizing current value to a motor (1) for driving a blower fan of an air conditioner. In the fan control device for an air conditioner provided with the means (4), the lock determination means (4) stores a first reference current value group (Ia) including a plurality of reference current values corresponding to the applied voltage. a first memory means (4), before
And the first reference current value group (I
a) a second reference current value consisting of a plurality of reference current values each larger than
Second storage means (4) for storing a reference current value group (Ib)
And a first voltage (V1) that is a predetermined low voltage is applied to the motor.
When applied to (1) , the first reference current value (I1) corresponding to the first voltage (V1) is stored in the first reference current value group (Ia) stored in the first storage means (4). ), And the current supplied to the motor (1) at the first voltage (V1) is equal to the first reference current value (I
1) First determining means ( S ) for determining whether or not it is larger than
2, S3) and when the first determination means ( S2, S3) makes an affirmative determination, the voltage applied to the motor (1) is changed to a second voltage (V1) that is higher than the first voltage (V1).
(2) an applied voltage changing means (S5) for changing to (2);
A second reference current value (I2) corresponding to the voltage (V2) is determined based on the first reference current value group (Ia) stored in the first storage means (4), and the second voltage (V2) the motor (1) wherein the energization current to the second in
Second to determine whether the current value is larger than the reference current value (I2)
And determination means (S7), when said determination is positive by the second determination means (S7), the energization stopping hand stopping the energization of it is determined that the lock of the motor (1) Previous Stories motor (1)
When a negative determination is made by the stage (S8) and the second determination means (S7), the applied voltage is reduced to the first voltage (V1).
Voltage return means (S9) for returning to
9) The third voltage corresponding to the first voltage (V1) returned in
The reference current value (I3) is stored in the second storage means (4).
Is determined based on the obtained second reference current value group (Ib).
Both to the motor (1) at the first voltage (V1)
Is larger than the third reference current value (I3).
And third determining means (S10, S11) for determining whether or not
To provide is a technical means.

[0006]

According to the present invention , a first low-voltage motor is used .
When the voltage is applied, the first determination means determines whether the current supplied to the motor at the first voltage is equal to the current supplied to the motor and stored in the first storage means.
One set of reference current values is determined corresponding to the first voltage.
Performing a first determination based on the first reference current value. As a result of the first determination, even when it is determined that the former is larger, the conclusion that "the motor is locked" is not immediately given. The reason for the above-mentioned determination result is that the applied first voltage is a relatively low voltage at which the difference between the detected current value and the reference current value is small with respect to the magnitude of the motor variation or the like. This is because the detected current value may just happen to exceed the first reference current value due to variations in the motor or other causes. Therefore, as described above, when it is determined by the first determination that the former is higher, the applied voltage changing means changes the applied voltage to the motor to the second voltage higher than the first voltage, and determining means, the energizing current to the motor at the second voltage, the first reference stored in the first storage means
The second determination is performed based on the second reference conduction value determined from the current value group corresponding to the second voltage. Also, in the result of the second determination, when it is determined that the former is larger, it is considered that the motor is actually locked. At this time, the power supply to the motor is stopped by the power supply stopping means, and the motor burns out. And so on. On the other hand, when the result of the second determination is that the former is smaller, the reason why the result of the first determination is as described above is that the first applied voltage is relatively low as described above. low, as a result, the detection current value by the variation or other causes of the motor is considered to have been only exceeded chance the first reference current value, at this time is regarded as "motor is not locked", the voltage return By means, the voltage applied to the motor is returned to the original first voltage according to the control operation of the air conditioner. Also, the motor return is marked by the voltage return means.
After the applied voltage is returned, the third judging means outputs the first reference voltage.
Second storage means each larger than each reference voltage value of the flow value group
From the second reference current value group stored in
Determine the corresponding third reference current value and return the applied voltage
Current to the motor at the time is larger than this third reference current value
It is determined whether or not.

[0007]

As described above, according to the present invention, the first judgment is made when the voltage applied to the motor is the first voltage,
Even if the result of the determination is “there is a possibility of locking”,
Since the voltage applied to the motor is set to a higher second voltage and the second determination is performed, the first determination is made according to the result of the second determination.
It is possible to determine whether the result of the determination is as described above due to the lock of the motor, the variation in the motor, or other causes. Therefore, when the result of the above determination is "lock of the motor", the energization of the motor can be stopped to prevent the motor from burning, etc., and the result of the above determination can be "motor variation and other causes."", The applied voltage of the motor is returned to the original first voltage according to the control operation of the air conditioner, and a stable and comfortable air conditioning operation can be maintained. In addition, in the case of a small lock state that can be released due to heat generation or the like due to energization of the motor, the lock may be released by energization during the first determination. In the second determination, the lock determination is denied. Therefore,
In the case where the lock determination is performed only in one stage, even if the motor is not driven due to the lock determination, the lock determination is performed in two stages of the first determination and the second determination as in the present invention. By doing so, it is possible to eliminate problems such as stopping the power supply to the motor. In this case, in the first determination, a relatively low voltage is applied to attempt to release the slight lock state, and then the applied voltage is increased to perform the second determination. (2) Since the voltage is not applied continuously for the time corresponding to the sum of the respective voltage application times in the determination, the determination is not performed, so that when the lock is actually locked, the motor may be burnt or the energizing element may be damaged. There is no. Therefore, the release of the lock in the slight lock state and the protection of the motor and the like in the case of the actual lock can both be achieved. In addition, negative in the second judgment
When the voltage applied to the motor is returned to the original
Is the first determination based on the first reference current value in the first determination.
Rather than a constant, the set larger than the first reference current value group
2 From the reference current value group,
The determination is made based on the third reference current value corresponding to the pressure
Therefore, an affirmative determination is made again and the motor is driven.
There is no trouble such as stoppage of the vehicle. Sand
That is, the reference current value group is set to a second group larger than the first reference current value group.
If only the quasi-current value group is used,
Determined from the second reference current value group set to the threshold value.
The determination is performed using the reference current value. in this way
If the judgment is made only with the large reference current value,
If the voltage applied to the motor is low,
The difference between the current and the reference current should be small.
Even if the reference current value is larger than the motor current value
Therefore, even though it is actually locked,
False judgment of "unlocked" when affected
May be achieved. However, in the present invention,
Initially the first reference current determined from the first reference current value group
Make a decision based on the value, and if a positive decision is made there,
Means that the current applied to the motor is
It is possible to determine whether or not an erroneous decision
You. In the present invention, the lock is determined in this re-determination.
If not, assume that the motor is not locked
Even in normal operation, if no trouble occurs
The second reference current consisting of a large reference current value
Since the process proceeds to the third determination based on the value group,
Lock determination at the time of
Stable air conditioning with little hindrance to air conditioning operation such as wind stop
Operation can be ensured.

[0008]

Next, the present invention will be described based on an embodiment of an air conditioner for a vehicle. The vehicle air conditioner of the present embodiment whose circuit diagram is shown in FIG.
A blast motor, an evaporator, a heater core and the like are arranged, and heating and cooling are automatically selected according to a set temperature or the like and the amount of blast is automatically operated. The present invention provides a DC motor for driving the blast fan. (Hereinafter referred to as blower motor).

In FIG. 1, 2 is an ignition switch, 3 is a blower relay for controlling power supply to the blower motor 1, 4 is a microcomputer (hereinafter referred to as microcomputer) for controlling air conditioning, and 5 and 6 are for energizing the blower motor 1. Power transistor 7, power transistor 5,
6 is a bypass resistor that is used to energize the blower motor 1 by itself when the blower motor 1 is activated, and that the blower fan is weakest Lo (low). Has a resistance value such that a fan speed corresponding to is obtained. Reference numeral 8 denotes a Hi relay that directly applies the voltage of the battery 9 by bypassing the power transistors 5 and 6 and the resistor 7 to drive the blower motor 1 at a fan speed corresponding to Hi (high) in which the blower fan is strongest. The current detection resistor detects a voltage Vr corresponding to a motor current value Im flowing through the blower motor 1.

On the other hand, an operation panel 20 for giving an operation instruction to the microcomputer 4 includes an air volume setting device 21, a room temperature setting device 22, a blowing mode setting device 23, and other operations such as a suction mode setting device and an air conditioner switch. And a blower motor lock display 30 for displaying when the lock of the blower motor 1 is detected. The microcomputer 4 includes an inside air sensor 25, an outside air sensor 26, and other sensors 27 for air-conditioning control, and also controls a compressor, a water valve, and a temperature control damper that are driven according to a target temperature, and selects an air blowing state. An inlet switching damper, an outlet switching damper, and the like, which are driven by the actuator, are provided as the actuator 40. Reference numeral 4a denotes an A / D converter which digitally converts the applied voltage Vm between the terminals of the blower motor 1 and the voltage Vr detected by the galvanometer resistor 10 together with the operation signals from the operation panel 20 and the detection signals of the sensors. Convert to a signal. 4b is D /
A converter.

Next, the determination of the lock of the blower motor 1 by the microcomputer 4 in the vehicle air conditioner having the above configuration will be described. When the blower motor 1 is not locked, the motor current value Im indicates a steady current value. When the blower motor 1 is locked, the motor current value Im is significantly larger than the steady current value. detects a motor current value Im, which is made by whether or larger than the reference current value for determining the lock. Since the motor current value Im varies depending on the voltage applied to the blower motor 1 irrespective of whether the blower motor 1 is locked or not, the reference current value is determined by a predetermined arithmetic expression using the voltage Vm applied to the blower motor 1. Is provided as a reference current value group including a plurality of reference current values determined according to

Conventionally, a reference current value group for determining whether or not the blower motor 1 is locked has a voltage Vm applied to the blower motor 1 as shown in FIG. 2 so that there is no problem in normal operation. Are calculated as a first reference current value group Ia corresponding to each applied voltage Vm. However, when the applied voltage Vm is low, there is a possibility that the detected motor current value Im becomes larger than the reference current value of the first reference current value group Ia due to variations in the blower motor 1 or the like. Because
A plurality of reference current values larger than the first reference current value group Ia are similarly calculated corresponding to each applied voltage Vm to obtain a second reference current value group Ib. The first reference current value group Ia is changed to the second reference current value group Ib according to the result of the re-determination in one determination. This prevents the blowing operation from being stopped due to erroneous lock detection when the lock is not performed.

The operation of the air conditioner for a vehicle will be described below with reference to FIGS. When the ignition switch 2 is turned on, power is supplied to the microcomputer 4 and the microcomputer 4 starts. Air volume setting unit 21 is off (OFF)
(In step 1, N
O), the air-conditioning operation according to the operation panel 20 is not performed, and the operation waits until it is turned on. When the air volume setting device 21 is turned on by operating the air volume desired by the driver or automatically (AUTO) (YES in step 1), predetermined activation control is performed. In the start-up control, for example, the blower relay 3 is turned on while the power transistors 5 and 6 are kept off, and the voltage V1 (for example, 4
When V) is applied, energization of the blower motor 1 is started,
At this time, the 2-second timer starts measuring time.

When the blower motor 1 is energized, an arithmetic expression for calculating the first reference current value group Ia is selected. Subsequently, the voltage V1 applied to the blower motor 1 and the voltage Vr are detected by the current detection resistor 10. Then, the reference value I1 in the first reference current value group Ia is determined based on the voltage V1 (step 2), and the motor current value I based on the voltage Vr is determined.
m is detected, and a first determination is made in which the motor current value Im is compared with the reference value I1 of the first reference current value group Ia.

If the motor current value Im is smaller than the reference value I1 of the first reference current value group Ia (NO in step 3), it is determined that the blower motor 1 is operating normally, and the two-second timer After the completion of the time counting, the start control is terminated, and the operation shifts to an air conditioning operation in accordance with the operation of the operation panel 20 (step 20). An air volume corresponding to the operation can be obtained. If the motor current value Im is larger than the reference value I1 of the first reference current value group Ia (YES in step 3), it is repeatedly determined whether or not this continues for 2 seconds (NO in step 4). If the motor current value Im becomes smaller than the reference value I1 within this time, the operation shifts to the air conditioning operation as in the case described above.

If the state where the motor current value Im is larger than the reference value I1 continues for 2 seconds (YES in step 4), the blower motor 1 may be locked, although the blower motor 1 may be locked. Whether the motor current value Im has exceeded the reference value I1 due to this, or whether the motor current value Im has accidentally exceeded the reference value I1 due to some external factor is not determined at this time. Therefore, the voltage Vm applied to the blower motor 1 is temporarily changed by the Hi relay 8 to a voltage V2 (for example, 12 V) corresponding to the fan speed Hi.
(Step 5), and waits for 2 seconds after the voltage Vm applied to the blower motor 1 becomes the voltage V2 (NO in step 6). In the calculation for calculating the first reference current value group Ia with the change of the applied voltage Vm of the blower motor 1, the reference value I2 corresponding to the new voltage V2 is calculated.

After 2 seconds (YES in step 6),
The motor current value Im is compared with a reference value I2 corresponding to the voltage V2 in the first reference current value group Ia to determine again whether the blower motor 1 is locked.
In the above case (YES in step 7), it is determined that the blower motor 1 is locked, and if the blower motor 1 is continuously energized further, the blower motor 1 is burned or the blower motor 1 is energized. Therefore, the power supply to the blower motor 1 is stopped (step 8), and the fact that the lock of the blower motor 1 has been detected is indicated by the motor lock indicator 30 on the operation panel 20. I do.

In the re-determination of the lock in the first determination, if the motor current value Im is smaller than the reference value I2 (NO in step 7), the applied voltage Vm is a relatively low voltage V1, so that the reference value I1 When the lock is erroneously detected in the lock determination based on that, and the applied current to the blower motor 1 is increased by changing the applied voltage Vm to the voltage V2 and the torque is increased, the blower motor 1 easily starts rotating. Thing, or
It is conceivable that the ice containing snow melts due to the heat generated by the application of the voltage V2 and the lock is released. In any case, the blower motor 1 can be regarded as not locked. Therefore, in such a case, the voltage Vm applied to the blower motor 1 is
(Step 9).

However, since it is not preferable that an erroneous lock is detected again, the reference current value group for lock determination is changed from the first reference current value group Ia to the second reference current value having a larger reference current value. The current value group is changed to the current value group Ib (step 10), and the lock is determined by the second determination based on the second reference current value group Ib. As a result, the applied voltage Vm
Is the same voltage V1, the reference current value has been changed to a larger value. Therefore, as long as the blower motor 1 operates normally, the possibility of repeatedly detecting the lock is very low.

In the second determination, when the motor current value Im is smaller than the reference value I3 of the second reference current value group Ib (NO in step 11), the process proceeds to step 20, and thereafter, the operation of the air conditioner is started. The blower motor 1 is controlled according to the control operation. For this reason, the blowing operation according to the control operation of the air conditioner is reliably obtained, and stable operation can be ensured.

Also, should the motor current value Im be equal to the reference value I
If it is 3 or more (YES in step 11), if it is continued for 2 seconds (YE in step 12).
S) As the detection of the lock, the process proceeds to step 8 to stop the power supply to the blower motor 1 and display the motor lock indicator 30. In step 20, the lock determination is repeatedly performed in accordance with the changed applied voltage of the blower motor 1. At this time, when the process proceeds from step 3, the first determination is performed. The lock determination is performed by the second determination.

By the above-described lock determination control operation, for example, even if the motor current value Im temporarily becomes larger than the reference value I1 due to the inrush current as shown in FIG.
If it becomes smaller than the reference value I1 within two seconds, the lock is not detected in the first determination thereafter, and the air conditioning operation is performed stably. Further, as shown in B, even when the motor current value Im becomes larger than the reference value I1 in the first determination due to variation or the like, the voltage V
If the lock is not detected in the determination in step 2, the voltage is returned to the original voltage again, and thereafter, the second determination is performed based on the second reference current value group in which the lock is difficult to be detected. Less likely to occur. Further, when the blower motor is actually locked, C
As shown in, in the two determinations in the first determination,
In both cases, the motor current value Im larger than the reference values I1 and I2 is detected, so that the power supply to the blower motor is reliably stopped, and the blower motor or the power transistor is damaged.
Destruction can be prevented.

In the above-described embodiment, in the start control of the blower motor, the energization is performed by a constant voltage only by the bypass resistor, but the blower motor may be started by applying a voltage corresponding to the operation state of the operation panel. Good. Also,
For the re-determination, the applied voltage of the blower motor is changed from the voltage of the fan speed Lo to the voltage of Hi,
The voltage may be changed to a voltage obtained by adding a fixed voltage (for example, 2 V) to the applied voltage at the time of starting.

FIG. 5 shows a second embodiment of the present invention. In the first embodiment, the voltage applied to the blower motor 1 is changed. However, in the second embodiment, the voltage applied to the blower motor 1 is kept constant and the duty of the power MOSFET 5A is changed via the duty generator 4c. PW changing ratio
M control is performed. In this case, the voltage applied to the blower motor,
By detecting the motor current value as an average voltage and an average current by an integration process, lock determination can be performed in the same manner as in the first embodiment. In each of the above embodiments, the air conditioner for a vehicle that performs cooling and heating has been described. However, an air conditioner that performs cooling or heating alone may be used, or a blower controller that only controls air blowing may be used.

In each of the embodiments described above, the reference current value group is calculated based on the applied voltage. However, two reference current value groups corresponding to each applied voltage are provided in the memory of the microcomputer. The reference value may be read according to the applied voltage detected from the first or second reference current value group.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment of a vehicle air conditioner showing an embodiment of the present invention.

FIG. 2 is a characteristic diagram of an operating current and a reference current value group with respect to a voltage applied to a blower motor in a vehicle air conditioner according to an embodiment of the present invention.

FIG. 3 is a flowchart for explaining an operation related to a lock determination of the first embodiment of the vehicle air conditioner according to the embodiment of the present invention.

FIG. 4 is a time chart for explaining an operation related to lock determination of the first embodiment of the vehicle air conditioner according to the embodiment of the present invention.

FIG. 5 is a circuit diagram showing a second embodiment of the vehicle air conditioner according to the embodiment of the present invention.

FIG. 6 is a characteristic diagram of an operating current and a reference current value group with respect to an applied voltage of a blower motor in a conventional vehicle air conditioner.

[Explanation of symbols]

Reference Signs List 1 blower motor (motor) 4 microcomputer (fan control device of air conditioner, lock determination means, reference current value group changing means, applied voltage changing means) Vm applied voltage Im motor current value (conduction current value) Ia first reference Current value group Ib Second reference current value group

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-B-62-48079 (JP, B2) JP-B 3-29999 (JP, B2) JP-B 3-29997 (JP, B2)

Claims (1)

(57) [Claims] A lock determining means (4) for detecting a voltage and a current value applied to a motor (1) for driving a blower fan of an air conditioner and determining lock of the motor (1).
In the fan control device for an air conditioner, the lock determination unit (4) includes a first current value including a plurality of reference current values corresponding to the applied voltage .
First storage means (4) for storing a reference current value group (Ia)
And the first reference current value group (I
a) a second reference current value consisting of a plurality of reference current values each larger than
Second storage means (4) for storing a reference current value group (Ib)
And a first voltage (V1) that is a predetermined low voltage is applied to the motor.
When applied to (1) , the first reference current value (I1) corresponding to the first voltage (V1) is stored in the first reference current value group (Ia) stored in the first storage means (4). ), And the current supplied to the motor (1) at the first voltage (V1) is equal to the first reference current value (I
1) First determining means ( S ) for determining whether or not it is larger than
2, S3), and when the first determination means ( S2, S3) makes an affirmative determination, the voltage applied to the motor (1) is increased to a second voltage (V2) higher than the first voltage (V1). And a second reference current value (I5) corresponding to the second voltage (V2).
2) is replaced by the first storage means stored in the first storage means (4) .
And determines based on the reference current value group (Ia), the energizing current to the motor (1) at the second voltage (V2)
Lock but the second reference current value and the second determination means determines greater or not than (I2) (S7), when a positive determination is made by said second judging means (S7), the motor (1) and determination to energization stop means for stopping the previous SL power supply to the motor (1) (S8), when the negative determination is made by the second determination means (S7), the applied voltage the first voltage (V1) Voltage return
(S9) and the first voltage returned by the voltage return means (S9).
The third reference current value (I3) corresponding to (V1) is
2 the second reference current value group (I
b) and the first voltage (V
The current supplied to the motor ( 1) in 1) is the third reference current.
Third determination for determining whether the current value is larger than the current value (I3)
Means (S10, S11) for controlling the fan of the air conditioner.