JPS6141769B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a blower fan speed control device suitable for use in vehicle air conditioners, etc. When the motor current increases abnormally or the motor terminal voltage abnormally drops, the blower fan speed control device The present invention relates to a blower fan speed control device that stops the current of a fan.

Conventional speed control for vehicle ventilation fans generally involves switching a large-capacity resistor between 2 to 4 stages to control the rotation speed, and in the event of an abnormality such as the motor locking up, the heat generated by the resistor is used to control the rotation speed using a temperature fuse. Either the power supply was stopped, or the resistor itself was melted due to heat generated by the resistor.

However, such a conventional configuration has the disadvantage that the operation of the fuse and the blowing of the resistor are unreliable, and it takes a long time until the power supply stops, which adversely affects the motor. By the way, it has been proposed to use a power transistor or the like instead of a resistor in order to control the speed of a blower fan using a continuously variable speed method. This resulted in the disadvantage that protection such as

If we consider the causes of motor lock here, there are two possible causes: lock due to foreign matter and lock in cold regions, that is, transistor freezing due to snow getting in, and oil becoming hard and locking. In the former case, there is no possibility of the lock being released over time, but in the latter case, the lock was often released due to the heat generation of the transistor before the transistor was destroyed.

The present invention overcomes the above-mentioned drawbacks.

An object of the present invention is to provide a continuously variable speed control device using a power transistor or the like to control the speed of a blower fan, and also to provide a relay contact and a galvanometric resistor in the electric circuit of the motor, so that the current flowing through the galvanic resistor is When the motor terminal voltage rises abnormally, or when the motor terminal voltage drops abnormally, the motor lock is detected, and based on the outside temperature etc. at that time, it is determined whether this lock will be released over time, and if there is no possibility of release,
The relay contacts are immediately opened to cut off the current to the motor, but if there is a possibility that the lock will be released, power will continue to be supplied to the motor for a certain period of time after the lock is detected, and if the lock is not released during that time, The purpose of this is to open the relay contacts, cut off the current to the motor, and protect the motor and power transistor.

The configuration of the present invention will be explained using FIG. 2. The structural features of the device of the present invention are as follows: detection means 111, 1 for detecting motor lock;
12, and determination means 1 for determining the possibility of motor locking.
18, a stop control means 119 for stopping energization to the motor when the detection means detects that the motor is locked and there is no possibility of the motor being locked; energization control means 121 that energizes the motor within a limited time when there is a possibility;
122, 123, 119.

EMBODIMENT OF THE INVENTION Hereinafter, the ventilation fan speed control device according to the present invention will be explained in detail according to an embodiment.

FIG. 1 shows a circuit diagram of a blower fan speed control device according to the present invention. In FIG. 1, a microcomputer is used which performs arithmetic processing according to a predetermined air conditioner control program.

1 is an air conditioner operation panel, which includes an air volume setting device 1a for stopping the air conditioner and selecting blower mode OFF, AUTO, and Lo to Hi; a room temperature setting device 1b for setting the room temperature (°C); and a suction blowing mode (not shown) selected. It has a mode setting device, a blower motor lock indicator 1c, etc. 2 is a sensor that detects the outside temperature, 3 is a sensor that detects the inside temperature, 4
are other outlet temperature sensors, etc. 5 is a direct current motor for driving the ventilation fan, that is, a blower motor; 6 is a galvanic resistor having a minute resistance value for detecting the motor current; Tr ₁ and Tr ₂ are power transistors for controlling the speed of the ventilation fan; 8 is a fan speed control circuit; This is a resistor with a large resistance value equivalent to Lo, and it works to partially bypass the motor current rather than letting it flow entirely to the power transistors Tr ₁ and Tr ₂ , and to start the motor. 9 is a Hi relay for operating the blower motor 5 in Hi state. Reference numerals 10 indicate a voltage V _M between the motor terminals, a voltage V _R across the galvanic resistor 6 corresponding to the motor current I _M , and a control panel 1 for detecting motor lock with an A/D converter;
Outside air sensor 2, inside air sensor 3, other sensors 4
It functions to convert the analog signal into a digital signal and send it to the microcomputer 11. The microcomputer 11 is a single-chip computer that performs arithmetic processing according to a predetermined air conditioner control program. 12 is a D/A converter which converts the digital air volume signal from the computer 11 into an analog signal and sends it to the power transistors Tr ₁ and Tr ₂ . Reference numeral 13 denotes an actuator (not shown) for driving the suction and outlet switching dampers, temperature control dampers, other compressors, and water valves of the air conditioner, which operates according to command signals from the microcomputer 11. 14 is batsuteri, 15
is the ignition (IG) switch. 16 is a heater relay that turns on and off the blower power supply.

FIG. 2 is a flowchart showing the processing procedure of the blower fan speed control device according to the present invention.

In a vehicle equipped with the device of the present invention, when the IG switch 15 is turned on, the microcomputer 1
1 is supplied with power, and arithmetic processing is started from an initialization routine at step 100. Step 100 sets initial values necessary for arithmetic processing. Especially regarding blower control, the blower lock flag F is set.
_R = 0, air conditioner start flag F _S = 0, and low temperature blower lock flag F _H = 0 are set. In the next step 101, a data reading routine is performed to set the blower mode, (OFF, AUTO, Lo to Hi), outside temperature ( Tam), internal temperature, other sensor blower motor terminal voltage (V _M ), value converted from the voltage V _R across the galvanic resistor to motor current (I _M ), and other data such as setting devices are stored in the specified memory. Process. Step 102 is a step for determining whether the air volume setting device is in the off mode, that is, the air conditioner is not operating. When in the off mode, the process goes to step 103, where the heater relay is turned off, the actuator is stopped, and the start flag F _S is set to 0. After processing, the process goes to step 101, and steps 101, 102, and 103 are repeated until the off mode is released. Next, if you are not in off mode,
Go to step 104, determine whether the motor is locked from the lock flag F _R , and set F _R =
1 (when locked), the motor lock indicator 1c is activated in step 105, and step 12, which will be described later, is performed.
The process moves on to A/C control program processing other than blower control in step 5. When F _R =0, the process goes to step 106, where it is determined from the start flag F _S whether it is time to start the A/C, and at the time of start (F _S =0), the blower motor start control, that is, when the motor is started, the power is controlled for a certain period of time. Open transistors Tr ₁ and Tr ₂ ,
A current is applied to the motor 5 through the Lo resistor 8, and the power transistor due to excessive starting current
Control is performed to protect Tr ₁ and Tr ₂ from destruction. Specifically, when F _S =0 (at the start) in step 106, the process goes to step 107 and sets timer _T1 to 0.
Start, set F _S =1, step 108
When the heater relay 16 is turned on, the blower is turned on at the same time.
It is fixed at Lo (power transistors Tr ₁ and Tr ₂ are opened), and the process moves to step 125. If it is not the start time at step 106 (F _S =1),
The process goes to step 109, and it is determined whether 2 seconds have elapsed on the timer _T1 . If it is within 2 seconds, nothing is done, that is, the process goes to step 125 without turning on the blower Lo. 2
After the second has elapsed, the timer _T1 is stopped in step 110, and the process moves on to a process for determining whether or not the motor 5 is locked.

FIG. 3 shows a voltage/current characteristic diagram of the blower motor used in the present invention during normal operation and when the blower motor is locked.
That is, it shows the applied voltage V _M and current I _M of the blower motor, where characteristic a is the measurement result when the blower motor is normal, and characteristic b is the measurement result when the blower motor is locked.

As can be seen from FIG. 3, when the motor 5 is locked, the current increases abnormally. Therefore, a lock judgment criterion is set as shown by the broken line C, and the motor current I _M with respect to the voltage V _M at that time is lower than the broken line C. If it is large, it can be determined that the lock is in place. Therefore, according to the present invention, in step 111, a reference current I, which is a lock judgment criterion, is determined from the motor applied voltage V _M , and in the next step 112, a comparison is made with the motor current I _M determined from the galvanic resistor 6. , so that I _M
>I, it is determined to be locked and the process proceeds to step 113.
If not, go to step 114, set the low temperature lock flag to _FH = 0, and at the same time stop timer _T2 if it is running, and go to step 1.
In step 15, determine whether the air volume setting device 1a is automatic (AUTO) or manual (Lo~Hi), and if it is manual,
At step 116, a signal is sent to the D/A converter 12 so as to achieve the air volume set by the air volume setting device 1a, and the process proceeds to step 125. On the other hand, in the case of automatic (AUTO), go to step 117,
Conventional blower automatic (AUTO) control, for example, automatically increases the air volume as the difference between the room temperature and the set room temperature increases, or increases the air volume when the air temperature is high or low, and when the temperature is intermediate. Control is performed to reduce the air volume, and the process moves to step 125. When it is determined in step 112 that the motor is locked, the process goes to step 113, where the low temperature motor lock flag F _H is monitored and F _H =1.
If so, go to step 123, otherwise go to step 123.
In step 119, it is determined whether the outside temperature is above 0°C, that is, whether the lock has a possibility of being unlocked due to snow, etc. If it is above 0°C, it is determined that there is no possibility of unlocking. The heater relay is turned off, that is, the power supply to the blower motor 5 is cut off, and in the next step 120, the blower lock flag F _R is set to 1, and the process moves to step 125. If it is determined in step 118 that the outside air is below 0°C, that is, there is a possibility that the motor lock may be released, the blower motor is set to Hi and energized for a certain period of time, and when the lock is released, normal blower control is performed, otherwise, the process proceeds to step 119. Processes forward motor current cut. Specifically, in step 121, timer _T2 is started and the low temperature lock flag _FH =
1, and in the next step 122 blower Hi
After turning on the relay 9 and operating the blower motor Hi, the process proceeds to step 123 where it is determined whether the timer _T2 has elapsed for 30 seconds. Timer T ₂ is 30
When the second elapses, the motor is energized for 30 seconds and the motor is locked despite the heat generated during that time to release the lock due to freezing. _T2 is stopped and the process moves to step 119 to cut off the motor current. If timer T ₂ <30 seconds in step 123, nothing is done, that is, the process goes to step 125 with the blower motor Hi.

In step 125, air conditioner control other than air volume control is performed, for example, the required air temperature is calculated from the data of each sensor setting device, and the actuator 13 is operated or the compressor and water valve are controlled so that the set room temperature is achieved. This is the air conditioner control processing routine. After processing, go to step 101.

In order to perform the above-mentioned calculation processing, if the motor is completely locked due to foreign matter entering the vehicle, a motor lock indicator is activated to notify the occupants, and the motor current is cut off to ensure protection of the power transistor and motor. be able to. In addition, when a motor lock occurs due to freezing due to snow, etc., it is determined from the outside temperature whether there is a possibility that a lock due to freezing will occur, and if there is a possibility, the motor will not flow current to the power transistor. It operates by energizing the motor for a certain period of time and automatically attempting to release the freeze lock due to the motor's self-heating. As a result, if the lock is released, normal blower motor control is performed, but if there is no lock, the motor lock indicator is immediately activated and the motor current is cut off.

In the embodiment of the device of the present invention described above, the activation timer T ₁
is set to 2 seconds, and the low temperature lock timer _T2 is set to 30 seconds, but this is not intended to be limiting. Also, the low temperature lock timer _T2 may be made longer depending on the outside temperature, for example, as the temperature is lower, as long as the motor does not break down, and when the temperature is high, the low temperature lock timer _T2 may be made shorter. The method of motor lock detection is not limited to the method of determining from the motor terminal voltage and current, and any conventionally known method may be used. Furthermore, although the blower is set to Hi when low temperature lock is detected, it may be fixed to the blower Lo.

As another embodiment for determining the possibility of freezing, that is, the high or low outside temperature, a temperature sensor attached to a predetermined part of the air conditioner duct, the engine cooling water of the vehicle, or the blower motor itself can be used.

As explained above, if the motor locks,
Based on the outside temperature, determine whether the lock can be released by energizing the motor, or whether it is completely locked. If the lock is completely locked, the current of the motor and power transistor is determined. If the motor is cut and there is a possibility of the lock being released, the motor is energized for a certain period of time, and if the lock is released during that time, it normally operates to control the blower, and if not, it operates to cut off the current of the motor and power transistor. Therefore, if the blower motor is completely locked without stopping due to erroneous motor lock detection, the motor and power transistor can be reliably protected, which is an excellent effect.

[Brief explanation of the drawing]

Fig. 1 is a circuit configuration diagram of a blower fan speed control device according to the present invention, Fig. 2 is a flowchart showing the processing procedure of the device shown in Fig. 1, and Fig. 3 is a diagram showing normal operation of the blower motor used in the present invention. The figure shows the voltage and current characteristics when locked. 1: Air conditioner operation panel, 1a: Air volume setting device,
1c: Motor lock indicator, 2: Outside temperature sensor,
5: Blower motor, 6: Galvanic resistor, 8: Lo resistor, 9: Blower Hi relay, 11: Microcomputer, 16: Heater relay, Tr ₁ , Tr ₂ :
power transistor.

Claims (1)

[Scope of Claims] 1. A current control transistor is connected in series with a DC motor for driving a blower fan, and the torque of the DC motor changes according to the power loss of this transistor, and the rotational speed of the blower fan is changed. A blower fan speed control device configured to vary the speed of the fan, comprising: a detection means for detecting lock of the motor; a determination means for determining a possibility of lock of the motor; and a detection means for detecting lock of the motor by the detection means. and a stop control means for stopping energization to the motor when there is no possibility of the motor being locked; A blower fan speed control device comprising: energization control means for energizing the motor within a specified time. 2. The blower fan speed control device according to claim 1, wherein the determining means compares the outside air temperature with a predetermined value. 3. The blower fan speed control device according to claim 1 or 2, wherein the energization control means includes a relay contact connected in parallel to the transistor, and means for closing the contact.