JPH0329998B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a blower fan speed control device suitable for use in automobile air conditioners, etc., which releases the lock when a motor lock is detected. The present invention relates to a blower fan speed control device that automatically performs desired control.

[Conventional technology]

Conventional speed control for automobile 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. The disadvantage was that it was not possible to provide protection.

[Problem to be solved by the invention]

If we consider the causes of motor lock here, there are two possible cases: lock due to foreign matter contamination and lock in cold regions, that is, motor freezing due to snow getting in, and oil becoming hard and locking. In the former case, there is no possibility that the lock will release over time, but in the latter case, there is a possibility that the lock will release due to the heat generated by the motor before the motor breaks down, and at the same time, the lock may release while the blower motor is rotating. Locks due to such freezing do not occur.

In this way, there are locks that can be released and locks that cannot be released, but if the current to the motor was immediately stopped when a lock was detected as in the conventional technology, the lock would be released. There was a problem in that the motor was stopped even when there was a possibility.

The present invention has been made in view of these problems.

The present invention focuses on the fact that the lock that can be released as described above occurs due to freezing of the motor due to low temperatures, solidification of oil, etc.
It is an object of the present invention to provide a blower fan speed control device capable of automatically performing control, also referred to as an unlocking effort, to attempt to release the lock if the motor is in a low temperature state when a motor lock is detected. purpose.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a blower fan speed control that controls the rotational speed of the blower fan by adjusting the voltage applied to a DC motor that drives the blower fan, as shown in FIG. 4. In the apparatus, a lock detection means detects a lock of the motor; a low temperature determination means determines whether the motor is in a low temperature state; a lock of the motor is detected by the lock detection means, and the low temperature determination means detects a lock of the motor; stop control means for stopping energization to the DC motor when the means determines that the motor is not in a low temperature state; the lock detection means detects a lock of the motor; and the low temperature determination means determines whether the motor is A technical means is adopted in which a lock release means is provided for energizing the motor within a limited time when it is determined that the motor is in a low temperature state.

[Effect]

According to the above configuration of the present invention, the lock detection means detects the lock of the motor, and the low temperature determination means determines whether or not the motor is in a low temperature state. The stop control means and the lock release means control energization to the DC motor in accordance with the lock detection means and the low temperature determination means.

The stop control means detects that the motor is locked and when it is determined that the motor is not in a low temperature state,
Since this lock is not a lock that can be released due to freezing of the motor, solidification of oil, etc., the power supply to the DC motor is stopped. This protects the motor and other peripheral circuits from the motor's lock current.

In addition, when the lock release means detects a motor lock and determines that the motor is in a low temperature state, this lock may be a lock that can be released due to freezing of the motor, solidification of oil, etc. Then, the DC motor is energized within a limited time. As a result, the motor lock caused by the low temperature is released by the motor's rotational force and its own heat generation, and by limiting the time when the motor is energized, the lock current is prevented from flowing for a long time, and if the lock is not released. The peripheral circuits such as the motor are protected against the lock current of the motor.

〔Effect of the invention〕

As described above, according to the present invention, peripheral circuits such as the motor can be protected against lock current, and if the motor is in a low temperature state and there is a possibility that the lock can be released, the motor can be locked within a limited time. Since the motor is energized, locks caused by low temperatures such as freezing of the motor and solidification of oil can be automatically released.

In addition, when a lock is detected and the motor is in a low temperature state, the motor is energized within a limited time, so peripheral circuits such as the motor can be protected from the lock current when the lock is not released. .

[Example] Hereinafter, the blower fan speed control device according to the present invention will be described in detail according to an example.

FIG. 1 is a block diagram of a blower fan speed control device according to the present invention, which uses a microcomputer that performs arithmetic processing according to a predetermined air conditioner control program.

In FIG. 1, reference numeral 1 denotes a control panel for operating the air conditioner, which is used to stop the air conditioner and select OFF, AUTO, or Lo to Hi, including the blower mode. An air volume setting device 1a, a room temperature setting device 1b for setting the room temperature, a mode setting device (not shown) for selecting a suction blowing mode, and a blower motor lock indicator 1c.
etc. 2 is a sensor that detects the outside temperature;
3 is a sensor for detecting the internal temperature, and 4 is another outlet temperature sensor. 5 is a DC motor for driving the ventilation fan, 6 is a galvanometric resistor with a minute resistance value to detect the motor current, Tr ₁ and Tr ₂ are power transistors for controlling the speed of the ventilation fan, and 8 is the fan speed equivalent to Lo. A resistor with a large resistance value of capacitance is used to transfer the motor current to the power transistor Tr ₁ ,
It does not flow completely to Tr ₂ , but works to partially bypass it and to start the motor. 9 is a Hi relay for operating the blower motor 5 in Hi state. 10
is an A/D converter that detects the motor lock by detecting the voltage V _M between the motor terminals, the voltage V _R across the galvanic resistor 6 corresponding to the motor current I _M , the control panel 1, the outside air sensor 2, Internal air sensor 3,
It functions to convert analog signals from other sensors 4 into digital signals and send them 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 that converts the computer's digital air volume signal into an analog signal and sends it to the power transistor. Reference numeral 13 is an actuator for driving the suction, outlet switching damper, temperature control damper, other compressors, and water valves of the air conditioner (not shown), which operates according to command signals from the microcomputer 11. Reference numeral 14 is a battery, and reference numeral 15 is an IG switch. . 16 is a blower,
Turning on/off the compressor clutch power supply (not shown)
This is a heater relay that turns off.

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

When the IG switch 15 is turned on in a vehicle equipped with the device of the present invention, the microcomputer 11
Power is supplied to the computer, and arithmetic processing starts from the initialization routine at step 100. step
100 sets the initial value necessary for arithmetic processing. Especially regarding blower control, the blower lock flag F _R =
0, Air conditioner start flag F _S = 0, Air conditioner running flag _D = 0, Start blower lock flag F _H =
In the next step 101, the blower mode (OFF, AUTO,
Lo to Hi), outside temperature (Tam), inside temperature, other sensor blower motor terminal voltage (V _M ), value converted from voltage across galvanic resistor V _R to motor current (I _M ), and other data from setting device, etc. Step 102, in which the air volume setting device is stored in a predetermined memory, is a step to determine whether the air volume setting device is in the OFF mode, that is, the air conditioner is not operating.If the air volume setting device is in the OFF mode, the process goes to Step 103, and the heater relay is turned off and the actuator is stopped. , the start flag F _S =0 and the air conditioner running flag F _D =0 are set.
101, and repeat steps 101, 102, and 103 until the off mode is released. Next, if it is not in off mode, go to step 104;
It is determined from the lock flag F _R whether the motor is locked or not, and if F _R = 1 (when locked), the motor lock indicator 1c is activated in step 105, and A/C other than blower control is activated in step 125, which will be described later.
Move on to control program processing. When F _R =0,
Go to step 106 and start flag F _S to A/
C Determine whether it is the start time or not, and at the start time (F _S =
0) includes blower motor start control, that is, the power transistor is activated for a certain period of time when the motor is started.
Tr ₁ and Tr ₂ are opened and current is applied to the motor 5 via the Lo resistor 8 to perform control to protect the power transistor 7 from being destroyed due to excessive starting current. Specifically, when F _S = 0 (at the start) in step 106, go to step 107 and set timer T ₁ to 0.
Start, set F _S = 1, turn on the heater relay 16 at step 108, and at the same time turn on the blower _L0.
(Power transistors Tr ₁ and Tr ₂ are opened)
and move to step 125. If it is not the start time at step 106 ( _FS = 1), step 109
Go to and determine whether timer T ₁ has elapsed for 2 seconds,
If it is within 2 seconds, do nothing, that is, blower Lo
After 2 seconds have elapsed, the timer _T1 is stopped in step 110, and the process moves on to a process of determining whether or not the motor 15 is locked.

FIG. 3 shows voltage and current characteristic diagrams of the blower motor used in the present invention during normal operation and when locked.
That is, the applied voltage V _M of the blower motor and the motor current I _M
The characteristics shown by the solid line a in the figure are those when the blower motor is normal, and the characteristics shown by the thick line b are the measurement results when the blower motor is locked.

As can be seen from Fig. 3, when the motor is locked, the current increases abnormally, so we set a lock judgment criterion as shown by the broken line C, and the current increases at that time.
If the motor current I _M with respect to V _M is larger than the broken line C, it may be determined that the lock is established. Therefore, according to the present invention, in step 111, the motor applied voltage is
A reference current I, which is a lock judgment criterion, is determined from V _M , and in the next step 112, it is compared with the motor current I _M determined by the galvanic resistor 6. If I _M > I, it is determined that the motor is locked. Go to step 126, otherwise go to step 114, set the start lock flag F _H = 0 and set the air conditioner running flag F _D = 1, and at the same time, if timer T ₂ is running, stop it and set air volume setting device 1a in step 115. is automatic (AUTO), manual (Lo
~ Hi), and if manual, adjust the D/A converter 1 so that the air volume is set with the air volume setting device 1a.
In step 116, the process of sending a signal to the device 2 is performed, and the process proceeds to step 125. On the other hand, in the case of automatic (AUTO), go to step 117 and perform conventional blower automatic (AUTO) control, for example, automatically increase the air volume as the difference between the room temperature and the set room temperature increases, or When the temperature is high or low, the air volume is increased, and when the temperature is intermediate, the air volume is decreased, and the process moves to step 125. When it is determined in step 112 that the blower motor is locked, the process proceeds to step 126, where a process is performed to determine whether the blower motor is locked while it is rotating. If the motor locks while it is rotating (F _D = 1), it is not a lock that can be released due to freezing, but a lock due to foreign matter, etc., so go to step 119 and turn off the blower (turn off the heater relay). In the next step 120, the blower lock flag F _R is set to F _R =1, and in the step 125
go to If F _D ≠ 1 in step 126, the motor is locked at startup, so depending on the outside temperature, the motor current may be cut off immediately after the lock is detected, or current may be applied to the motor 5 for a certain period of time to release the freeze. The program moves on to the program starting from step 113, which determines and processes.

Step 113 is where the startup flag F _H is monitored. When F _H = 1, a lock is detected at startup, and 2
Second timer _T2 operates and the blower is controlled to Hi (actually, motor 5 is locked, but motor 5
(with a Hi voltage being applied to), the process goes to step 123 where it is determined whether or not timer _T2 has elapsed for 2 seconds. When F _H = 0 in step 113, it is the first time that lock is detected at startup, so
The process moves to step 118 to determine the outside temperature. step
If the outside temperature is 0°C or higher in step 118, the lock is not due to freezing, so go to step 119, turn off the blower (heater relay off), and proceed to the next step 120.
Then, the blower lock flag F _R is set to 1, and the process moves to step 125. At step 118, the outside air is below 0℃,
In other words, if it is determined that there is a possibility of the motor lock being released, the timer _T2 is started in step 121, the low temperature lock flag _FH is set to 1,
In the next step 122, the blower Hi relay 9 is turned on to operate the blower motor at Hi.
Step to determine whether timer _T2 has elapsed for 2 seconds
Go to 123. When timer _T2 has elapsed for 2 seconds, the motor 5 is energized for 2 seconds, and the heat generated during that time causes the motor 5 to
If the motor is still locked even after trying to release the lock due to freezing, that is, there is no lock due to freezing, timer _T2 is stopped at step 124, and the process proceeds to step 119, where the motor current is cut off. . In step 123, if the timer H ₂ <2 seconds, 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, calculating the necessary blowing temperature from the data of each sensor and setting device, operating the actuator 13 to achieve the set room temperature, and controlling the compressor and water valve. This is a known 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, the 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, current should be passed to the power transistor. Instead, the motor is energized for a certain period of time to automatically attempt to release the freeze lock due to self-heating of the motor 5. If the lock is released, normal blower motor control is performed, but if the lock cannot be released, the motor lock indicator is immediately activated and the motor current is cut off.

Furthermore, when the lock is detected and the heater relay is turned off, the compressor also stops, so the evaporator will not freeze.

The embodiments described above may be modified and implemented as listed below.

(1) Start timer _T1 for 2 seconds, low temperature lock timer _T2
is set to 2 seconds, but this is not intended to be limiting.

(2) The low-temperature lock timer _T2 may be set depending on the outside temperature, for example, the lower the temperature, the longer the motor will not be destroyed, and the higher the temperature, the shorter the time.

(3) 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.

(4) When the low temperature lock was detected, the blower was set to Hi, but
You can also fix it on the blower Lo.

(5) In the embodiment, the motor lock is stored until the IG is turned off, but it may be refreshed in the off mode.

(6) Although lock detection is processed by software, it may also be configured by a hard logic circuit.

[Brief explanation of drawings]

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. FIG. 4 is a block configuration diagram of the present invention. 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 blower fan speed control device that controls the rotational speed of the blower fan by adjusting a voltage applied to a DC motor that drives the blower fan, comprising: lock detection means for detecting lock of the motor; low temperature determination means for determining whether or not the motor is in a low temperature state; and when the lock detection means detects that the motor is locked and the low temperature determination means determines that the motor is not in the low temperature state; stop control means for stopping energization to the DC motor; and within a limited time when the lock detection means detects that the motor is locked and the low temperature determination means determines that the motor is in a low temperature state. A blower fan control device comprising: a lock release means for energizing the motor. 2. The blower fan speed control device according to claim 1, wherein the low temperature determination means is configured to determine that the motor is in a low temperature state when the outside air temperature is below a predetermined temperature. 3. The lock release means includes a start determination means for determining whether or not the DC motor is immediately started, and when the lock of the motor is detected immediately after the start and it is determined that the motor is in a low temperature state. The blower fan speed control device according to claim 1, wherein the blower fan speed control device is configured to energize the motor within a limited time.