JPS5891396A - Fan speed controlling apparatus - Google Patents

Abstract

PURPOSE:To prevent faulty detection of motor lock, by stopping lock detection for a predetermined time when a control electric power is changed rapidly, and executing control during the while when the lock detection is stopped according to a lock signal. CONSTITUTION:When it is detected at a step 118 that the temperature of open air is lower than 0 deg.C, a timer T2 is started at a step 121, and a low-temperature lock flag is set at FH=1. Then, the step goes to a step 123 for judging whether 2sec are passed or not after T2sec elapses at the timer. In case that 2sec are passed at the timer T2, current is supplied to a motor for two seconds. Here, if the motor is locked even after trying to remove the lock due to freezing of the motor by the heat and torque imparted by current supply to the motor, it is judged that the lock is not due to freezing and the timer T2 is stopped at a step 124. Then, the step goes to a step 119 and stops current supply to the motor, so that it is enabled to prevent faulty detection of motor lock.

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 decreases, the blower fan speed control device The present invention relates to a blower fan speed control device that stops the current of a blower fan.

Conventional vehicle blower fan speed control generally involves switching a large-capacity resistor into 1-4 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 supply power to a temperature fuse. Either the resistor would stop, or the resistor itself would melt due to heat generated by the resistor.

However, in such a conventional structure, the reliability of the operation of the fuse and the blowing of the resistor is low, it takes a long time until the power supply stops, and there are defects that adversely affect the motor. On the other hand, it has been proposed to use a power transistor or the like instead of a resistor in order to control the speed of the fan in a continuously variable speed system. The drawback was that it could destroy the motor or even the power transistor.

If we consider the causes of motor locks, there are two possible causes: locking due to foreign matter contamination, and locking in cold regions, that is, freezing of the motor due to snow or oil becoming hard and sticky. In the former case,
There is no possibility that the lock will unlock over time, but in the latter case, the heat generated by the motor will cause it to break down before the seven-stage motor is destroyed.
Most of the time it was unlocked.

By the way, when actually performing a freeze lock release test, for example, a high voltage (generally 1 gV) is applied to a frozen motor.
) to unfreeze the motor, and at the same time as the motor starts rotating, switch to the Lo voltage (4 to 6 V when the motor is normal).
Frequently, the motor stopped, the motor rotation became extremely unstable, and the rotation speed also decreased.

Also, depending on the degree of freezing, Jin's unstable state could last for a long time.

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, etc. to control the speed of a blower fan. When the voltage increases abnormally or when the motor terminal voltage drops abnormally, the motor lock is detected, and the lock is detected. After a certain period of time motor <Hi
If the voltage is applied continuously and the lock is released during that time,
Since it was frozen and locked, we continued to supply high voltage for a certain period of time to completely unfreeze the blower motor, perform a form-up, and then quickly switch to normal air volume control when the blower motor is normal. Conversely, when the motor lock is not released, the relay contacts are opened to cut off the current to the motor and protect the motor and power transistor.

However, in order to realize the above control method, it is necessary that the motor lock detection mechanism operates correctly.

If the motor locks when the power supplied to the motor is not at its maximum, motor lock is detected (because the motor terminal voltage has abnormally decreased due to power loss in the power transistor, etc.). At this time, according to the above control procedure, when the motor (maximum power is supplied), the motor terminal voltage rises rapidly and becomes above the lock judgment level /L/J4, but the motor current increases gradually due to the inductance of the motor coil. It does not reach the lock judgment level immediately. Therefore, even though the motor is locked, immediately after the maximum power is supplied, the lock detection condition is not met and the motor lock detection mechanism judges that the motor is not locked. In addition, according to the above control procedure, after the lock is released and the maximum voltage is further supplied for a certain period of time, the normal air volume control is immediately performed.
It takes a long time for the motor to receive enough power to completely unfreeze the motor, so depending on the degree of freezing, the motor may remain unstable or even stop.

The present invention provides the above-mentioned speed control device in which, when motor lock detection is performed based on motor current and motor terminal voltage, the control power is suddenly changed and lock detection is stopped for a certain period of time during running. Control during the stop period is performed according to the lock signal immediately before the stop. With this method, it is possible to prevent erroneous detection of motor lock when implementing the above control method and obtain the desired effect.

Hereinafter, the blower fan speed control device according to the present invention will be described in detail according to embodiments.

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

1 is an air conditioner operation spring, which includes an air volume setting device 1m for stopping the operation of the air conditioner and selecting blower mode OFF, MUUTO, and LoNHi, and a room temperature setting device 1b1 for setting the room temperature ('C) and a suction blowing mode (not shown). It has a mode setting device for selection, a blower motor lock indicator 1 (1, etc.), 2 is a sensor that detects the outside temperature, 8 is a sensor that detects the inside temperature, and 3 is another outlet temperature sensor, etc. b is a DC motor for driving the blower fan, that is, a blower motor, 6 is a galvanic resistor with a minute resistance value for detecting the motor current, Trl and Tr2 are power transistors for controlling the speed of the blower fan, and 8 is the fan speed. Nishiri.

It is a resistor with a considerable capacity and a large resistance value, and works not to allow the motor current to flow completely through the power transistors Tr+eTraK, but to bypass a portion of the motor current, and to start the motor. 9 is 1lI for operating propeller motor b at Hi.
It is an i-relay. 10 is the motor terminal voltage VM for detecting motor lock at M/D2[J, the voltage across the galvanic resistor 60 corresponding to the motor current IME, vR, the controller to the panel l, the outside air sensor 2. Internal air sensor 3. Convert analog signals of other sensors 4 to digital signals,
It functions to send data to the microcomputer 11. The microcomputer 11 is a single-chip computer that performs arithmetic processing according to a predetermined air conditioner control program. 1z is a D/MU converter and the computer 11
A power transistor Trl converts the digital air volume signal into an analog signal.

It functions to send TrxK. 13 is a suction/outlet switching damper and a temperature control damper of an air conditioner (not shown).

Other actuators that drive the compressor and water pump operate according to command signals from the microcomputer II. 14 is a battery, and 15 is an ignition (IQ) switch. 16 is a heater relay that turns on and off the power source of the blower.

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 IQ switch 1b is turned on, power is supplied to the microcomputer 11 and the initialization routine of step 100 starts arithmetic processing. Step 100 sets initial values necessary for arithmetic processing, especially regarding blower control, blower lock flag FB=o, air conditioner start flag F8=
O, While the air conditioner is running, the low-temperature blower lock flag! UTO, Lo, Hi).

Outside temperature (T a m ), inside temperature, other sensors Prower motor terminal voltage (VM) Voltage across galvanic resistor
□ A heat treatment is performed to store i[(IM) converted from vH into electric current, and data of other killing devices, etc., in a predetermined memo 91. However, in step 1010, timer T!
When 0 (Ta (0.3 seconds), the VM and IM are considered to be in a transient state and the data is not updated, but otherwise, the data VM is changed to the data VM in step 1011.

Update the IM by transferring it to another memory location.

Step 10ffi 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 proceeds to step 103, where the heater relay is turned off and the actuator is stopped.

Start flag FB=0 Air conditioner running flag FD=O
10g and 1 until the off mode is released.
I will be returning 08. Next, if it is not the off mode, go to step 104 and judge whether the motor is locked from the lock flag l'R, and if FB=1 (locked), the motor lock indicator lC is displayed at step lO5.
is activated, and the process moves to step 186, a program for controlling the engine 10 other than the blower control, which will be described later. On the other hand, when FB=o, the process goes to step 106, and it is determined from the start flag F8 whether the Muda C star is 1 o'clock or not, and at the time of start (F&=
O) includes blower motor start control, that is, when starting the motor, the power transistors Trl and Trl are opened for a certain period of time, and a current is applied to the motor 5 via the Lo resistor 8;
Power transistor Try, Tr due to excessive starting current
Control is performed to protect against the destruction of 1.

Specifically, in the step log, Fs = o (at the start)
To do so, go to step 107, start timer TI at 0, set rB=t, and step 108 to start heater relay 1.
Turn on Prowa L at the same time as turning on 6.

(the power transistors T s and T T z are set in the open state 111), and the process moves to step 125. When it is not the start time (Fs=1) in step 106.

Go to step 109, and determine whether or not the timer T1 has elapsed for 3 seconds. If it is within 2 seconds, nothing is done and the
Exit to step 125 with Nonashi.

After two seconds have elapsed, the timer T1 is stopped in step 110, and the process moves on to a process of determining whether the motor 5 is locked.

FIG. 3 shows voltage/current characteristics of the blower motor used in the present invention during normal operation and when locked.

That is, the applied voltage VM and current IM of the blower motor are shown, and the characteristic a is the measurement result when the blower motor is normal, and the characteristic is the measurement result when the blower motor is locked.

As can be seen from FIG. 3, when the motor 6 is locked, the current increases abnormally, so a lock judgment criterion is set as shown by the broken line C, and the motor current IM with respect to the voltage VM at that time is larger than the broken line C. All you have to do is judge that the case is locked. Therefore, according to the present invention, in step 111, from the motor applied voltage VM, the reference I which is the lock judgment criterion is determined.
EiI is determined, and in the next step 11g, a comparison is made with the motor current IM determined from the galvanic resistor 6, and as a result, I
M) If I, it is determined to be locked and the process proceeds to step 1116.
Otherwise, go to step 114 and set timer T: to stop and IFI)=1. However, according to the present invention, in step 1110, it is determined whether the timer TI+ is 1 before 0.8 seconds have elapsed and t9 motor applied voltage VM and gFH are 1, and if 1, the motor 6 is unfrozen and the motor rotates. Since it shows Jin, who is an idiot who just started !, we go to the next step 1141 and start the timer Ts from 0 seconds, and at the same time! pH = 04C) tl[l
,, Proceeds to step lf6. FHH at step 1140
When the time is O2, the process goes to step 114g, and when the timer T1 has elapsed for 8 seconds, the process goes to the step of determining whether the timer T1 is round or not. Timer T3 is 2
If it is within seconds, go to step 1 $15. tD, once the freeze motor lock is released, the H
The process of fixing it to i is performed. Step 114
In step 2, when T3>8 seconds, the process goes to step 11421, stops the timer T3, and goes to step 115.

Also, in step 115, the air volume setting of 191m is automatically
TO) or manual (Lo to Hi), and if manual, adjust the D/D so that the air volume is set with the air volume setting device Hm.
Processing for sending a signal to the A converter 1g is performed in step 116, and the process proceeds to step 125.

On the other hand, in the case of automatic (AUTO), the process proceeds to step 117, where conventionally known blower automatic (UT, 0) control is performed, for example, the air volume is automatically increased as the difference between the room temperature and the set room temperature increases, or During blowing, control is performed such that when the temperature is 1 iC 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 the lock is determined in step 112, step l! 16, and a process is performed to determine whether or not the blower motor is locked during rotation. If the sweater is locked while rotating (FD=1), the lock is not due to freezing and may be released, but is due to foreign matter, etc., so go to step 119 and turn off the blower (heater release, turn off).
In the next step Igo, move the prowarotsukufugu FB to yR=
Set it to 1 and go to step 125. Step 126
In the case of l'D~l, it is locked at startup, so depending on the outside temperature, either cut the motor current immediately after detecting the lock, or let current flow to the motor for a certain period of time to release the freeze. The program moves to step 118, where the determination process is performed.

Step 118 is where the startup flag FH is monitored.
When = 1, lock is detected at startup and 8 second timer T2 is activated.
is operating and the blower is under H1K control (actually, motor 6 is locked, but Hi voltage is applied to motor 6), so timer T! The process advances to step lf8 where it is determined whether 2 seconds have elapsed. Step 11B
If FH-0 is detected, this is the first time that the startup lock is detected, so the process moves to step 118 to determine the outside temperature.

If the outside temperature is 0℃ or higher in step 118, the lock is not due to freezing, so go to step 119, turn off the blower (heater relay off) KL, and set the blower lock puffer FB = 1 in the next step 1!0. Step 11 &
Move to. If it is determined in step 11g that the outside air is below 0℃, and that there is a possibility of the motor being unlocked, step 1ill starts T2, sets the low temperature lock flag to F[, -1, and moves on to the next step. At step 12B, the blower Hi relay 9 is turned on to operate the blower motor at Hi, and the process goes to step tgs, where it is determined whether the timer 12 seconds have elapsed. When T2 has elapsed for 8 seconds, the motor 5 is energized for 2 seconds to release the lock due to freezing of the motor 6 due to heat generation and rotational torque during that time, but the lock is still locked. In other words, the lock is not due to freezing. Therefore, the timer T2 is stopped in step 124, and the process proceeds to step 119, where the motor current is cut. If T2 <2 seconds in step 111111, do nothing, that is, step 125 without propeller motor H4.
go to

In Stella 7'l 25, air conditioner control other than air volume control, for example, calculates the necessary blowing temperature from the data of each sensor and setting device, operates the actuator 18 to achieve the set room temperature, and controls air conditioning, compressor, and water pulp. After the processing, which is a conventionally known air conditioner control processing routine for controlling, the process proceeds to step 101.

In order to perform the calculation processing explained above, if the motor is completely locked due to foreign matter, etc.

Activating the motor lock indicator and notifying the occupants will cut off the motor current, ensuring the protection of the power transistor and motor. In addition, when the motor locks up due to freezing due to snow, etc., the motor KH1 is energized for a certain period of time without passing current to the power transistor, and the motor automatically attempts to release the freeze lock due to self-heating of the motor. . If the lock is released, a high voltage is further applied for a certain period of time to warm up the blower motor to completely release the freeze, and then normal blower motor control is performed, but if the lock is not present, the motor is immediately It activates the lock indicator and cuts the motor current.

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

Furthermore, since lock detection is stopped for a predetermined period of time when the control output of the motor is suddenly changed, erroneous determination of lock is prevented and correct operation can be ensured.

In the above embodiment, the start timer T1 is set to 2 seconds, the low temperature lock timer T1 is set to 8 seconds, the lock detection stop timer is set to O, and the a second timer T1 is set to 2 seconds, but the invention is not limited to this.

In addition, the low temperature lock timer T may be set depending on the outside temperature, for example, the lower the temperature, the longer the motor may be damaged, and the lower the temperature, the shorter the timer T may be.

Further, in the above embodiment, the motor lock is stored until the IQ is turned off, but it may be refreshed in the off mode.

Further, although lock detection is processed by a computer 10G, it may also be configured by a hard logic circuit.

- In the embodiment, motor freeze lock is determined based on whether the motor is locked at startup or whether it is locked when the outside temperature is low, but this is not intended to be limiting, and freezing can be determined based on either one. - That's fine, and there is no need to perform a freeze judgment.

As explained above, according to the present invention, when the motor is locked, a large voltage is applied to the motor for a certain period of time in an effort to release the lock, and when the motor is unlocked, it is possible that the motor was frozen and locked. Because of this, the motor is rotated at Hi for a certain period of time to warm up and completely release the freeze lock, and then normal air volume control is performed.
Since lock detection is stopped for a certain period of time in a transient state of the motor, there is an advantage that malfunctions due to erroneous detection do not occur.

[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. Shows the voltage/current characteristics diagram when locked. l...Air conditioner operation panel, ll&...air volume setting device, IC...motor lock indicator, 2...outside temperature sensor, 6...prower motor, 6...galvanic resistor, 8...
... Lo resistance N, 9... Prowa ■i Relay, 11.
...Microcomputer, 16-...Heater relay. Representative Patent Attorney Takashi Okabe

Claims (1)

[Claims] A current control fan is connected in series with a DC motor for driving the fan, and the torque of the DC motor changes in accordance with the power loss of the fan, thereby changing the rotational speed of the fan. In the fan speed control device, when the DC motor is locked, a maximum air volume voltage is applied to the DC motor for a certain period of time to make an effort to unlock the DC motor, and when the lock is released, the DC motor is further driven at the maximum air volume voltage for a certain period of time, and then the DC motor is normally operated. Shifts to air blow control,
On the other hand, if the lock is not released, the DC motor current is immediately cut off, and when the control output of the motor changes suddenly, the lock detection function is stopped for a predetermined period of time to prevent erroneous determination that the DC motor is locked. A blower fan speed control device that prevents