JPH07300011A - Blower fan motor control device - Google Patents

Abstract

PURPOSE:To efficiently variably control an output of a blower fan motor by reducing a loss in a transient period at on/off time, when a duty ratio of turning on a switching element is increased in PWM control. CONSTITUTION:Control of an output of a blower fan motor 1 is adjusted by PWM control, but when a duty ratio of 80 to 90% on-waveform is increased in the PWM control, since off-operation of a switching element 6 is not accurately performed, a switching loss in a transient period is increased, consequently in this case, by steadily turning on the switching 6, the switching loss is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blower fan motor controller capable of efficiently changing the output of a blower fan motor.

[0002]

2. Description of the Related Art For example, an output of a blower motor 1 attached to a blower of an automobile air conditioner as a blower fan motor is determined according to a temperature or an air volume set in the air conditioner. In the main circuit section 2 that directly drives the blower motor 1, a switch SW3 connected in series with the battery power source VB as shown in FIG. 4, a blower motor 1 connected to the switch SW3, and an output of the blower motor 1 are controlled. There is a variable resistor 4 for doing this.

The main circuit section 2 operates as follows.

To move the blower motor 1, the switch 3 is turned on to supply power to the blower motor 1. The electric power supplied to the blower motor 1 is the variable resistor 4
Was adjusted by.

However, if the output of the blower motor 1 is controlled by the main circuit section 2 as described above, as long as the blower motor 1 is in a movable state, the current flowing through the variable resistor 4 is always lost, and this variable resistance is lost. The power consumed by the container 4 can be expressed by the following equation.

Wr = Ib ² · Rv (1) Wr: Power loss in the variable resistor 4, Ib: Variable resistor 4
Current Rv: resistance value of variable resistor 4 For example, when the battery voltage is 12 (V), the maximum power consumption of the blower motor 1 is about 187 (W), and the internal resistance of the blower motor 1 is 0.17 (Ω). Then, the resistance value of the variable resistor 4 is set to 0.19 (Ω), and the power consumption of the variable resistor 4 at this time is calculated from the formula (1) to 21.
It can be 1 (W). As described above, the power adjustment by the variable resistor 4 always consumes wasteful power, and particularly when the blower motor 1 is at maximum power consumption, the power is consumed to the blower motor 1 or more, so that the battery is insufficiently charged or the battery having a larger capacity is used. A generator was needed. Further, the output control range of the blower motor 1 is determined by the variable range of the variable resistor 4. Therefore, in order to widen the output control range of the blower motor 1, a large variable resistor 4 is required or a device for switching complicated variable resistors is required.

Therefore, in order to improve the above-mentioned problems,
As shown in FIG. 5, the main circuit unit 2 is connected to the blower motor 1 connected in series with the battery power source VB, and is connected in parallel with the blower motor 1 to mainly absorb surges generated when the blower motor 1 is off. A surge killer diode 5, a switching element 6 connected to the blower motor 1 for PWM control, and a flywheel diode 7 connected in parallel to the switching element 6 for flowing a circulating current at the moment of switching off.

The surge killer diode 5 may be a snubber circuit including a varistor, a resistor, a capacitor, an inductance, a diode, etc. other than the diode. The switching element 6 may be a transistor, an IGBT, a thyristor, etc. as well as the FET.

The main circuit section 2 having such a configuration turns the switching element 6 on and off at a set cycle, changes the duty ratio which is the width of the on and off voltages, and changes the average voltage, thereby making the blower motor 1 output control (P
WM control). Therefore, in this device, since there is no restriction on the output control range by the variable resistor 4, the output control range of the blower motor 1 can be smoothly varied and the output can be controlled in a wide range.

The loss in the main circuit portion 2 mainly includes a surge killer diode loss in the surge killer diode 5 that occurs when the blower motor 1 is off and a switching loss in the switching element 6. The surge killer diode loss is mainly Since the blower motor 1 occurs when the blower motor 1 is off, the switching loss is the largest in the total loss ratio. Further, the switching loss in the switching element 6 can be divided into a loss when the switching element 6 is on and a loss when the switching element 6 is off. Losses when the switching element 6 is on include switching-on loss, which is a transitional loss at the moment when the switching element 6 is turned on, and on-resistance loss determined by the internal resistance of the element. Further, the loss when the switching element 6 is off includes switching-off loss which is a transient loss at the moment of turning off and flywheel diode loss which is a loss due to a circulating current in the flywheel diode 7.

The experimental data of the switching loss in this case is a solid curve up to a duty ratio of 80% as shown in FIG. The maximum loss in the main circuit section 2 was about 22 (W). Therefore, comparing the loss due to this device and the loss when the blower motor 1 is controlled using the variable resistor 4, the loss due to this device is about 1/10 of the loss when controlled using the variable resistor 4. The power loss could be significantly reduced as compared with the case where the blower motor 1 is controlled by the resistor 4.

[0012]

However, the above-mentioned PWM is used.
The switching loss in control increases as the current flowing through the switching element increases, but especially when the ON duty ratio of the switching element increases.
Since the OFF time width is narrow, the OFF operation of the switching element is not normally performed, and as a result, the transient loss during ON and OFF of the switching element increases.

Therefore, an object of the present invention is to reduce the transient loss at the time of on and off when the duty ratio of the switching element becomes large in the PWM control, and to efficiently change the output of the blower motor. It is to provide a blower control device.

[0014]

A blower fan motor control device according to the present invention for achieving the above object is an external input in a blower fan motor control device for PWM controlling a blower fan motor for varying an air volume. A signal input means for processing the generated signal, a reference value storage means for storing a predetermined output reference value of the blower fan motor, and a switching means for performing a PWM control switching operation of the blower fan motor. Driving means for driving the switching means, and the duty ratio of ON and OFF in the PWM control according to the signal from the signal input means is varied according to the required output of the blower fan motor, and the signal is the reference. If the output reference value of the blower fan motor stored in the value storage means is greater than or equal to the reference value, Etching means and having a PWM control unit for outputting a signal which becomes steadily on, the.

Also, the blower control device for an automobile according to the present invention is a blower control device for an automobile for PWM controlling a blower motor for varying the air flow rate of an air conditioner for an automobile, for processing a signal input from the outside. Signal input means, reference value storage means for storing a predetermined output reference value of the blower motor, switching means for performing a switching operation of PWM control of the blower motor, and drive means for driving the switching means. , The duty ratio of ON and OFF in the PWM control according to the signal from the signal input means is varied according to the required output of the blower motor, and the signal is equal to or more than the output reference value of the blower motor stored in the reference value storage means. In the case of a value, a signal that causes the switching means to be constantly turned on is sent to the driving means And having a PWM control means for force, the.

Further, the motor controller for an electric fan for an automobile according to the present invention is a motor controller for an electric fan for an automobile, which PWM-controls an electric fan motor for varying the amount of air blown to a cooler for an automobile, Signal input means for processing a signal inputted from the outside, reference value storage means for storing a predetermined output reference value of the electric fan motor, and switching operation for PWM control of the electric fan motor A switching means for driving the switching means, a driving means for driving the switching means, and an ON / OFF duty ratio in the PWM control according to a signal from the signal input means, which is varied according to a required output of the electric fan motor. , If the signal is equal to or greater than the output reference value of the electric fan motor stored in the reference value storage means, And PWM control means for the switching means to the driving means outputs a signal which becomes steadily on,
It is characterized by having.

[0017]

The blower fan motor control device of the present invention constructed as described above operates as follows.

In this device, when a signal requiring a small output from the blower fan motor is input from the signal input means, the PWM control means turns the connection between the load and the power source on and off to adjust the power. After performing processing for increasing the OFF duty ratio, a signal for increasing the OFF duty ratio is output to the driving unit,
The switching means switches in accordance with this signal, and the average voltage in PWM control can be brought close to 0 (V) to supply the small electric power required for the blower fan motor. Further, when a signal that requires a large output in the blower fan motor is input from the signal input means, PW
After the M control means performs a process for increasing the ON duty ratio of the PWM control, a signal for increasing the ON duty ratio is output to the driving means, and the switching means switches according to this signal to perform PWM.
It is possible to bring the average voltage in control close to the battery voltage, which is the power supply voltage, and supply the large amount of power required for the blower fan motor. Further, when the ON duty ratio of the PWM control is further increased by the signal from the signal input means and becomes equal to or larger than the output reference value of the blower stored in the reference value storage means, the PWM control means keeps the switching means steady. Signal is output to the drive means to turn on the switching means steadily in accordance with this signal.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION A blower control device for an automobile according to an embodiment of the present invention will be described below with reference to the drawings. It can also be applied as a motor control device.

The blower control device for an automobile according to the present embodiment includes a signal input section 11 which is a signal input means for processing a signal input from the outside and a predetermined blower motor 1 as shown in FIG. A storage unit 12 that is a reference value storage unit that stores an output reference value, a main circuit unit 2 that is a switching unit for performing a PWM control switching operation of the blower motor 1, and a drive for driving the main circuit unit 2. The blower motor in which the duty ratio of ON and OFF in the PWM control is changed according to the required output of the blower motor 1 according to the signal from the drive unit 13 as the means and the signal input unit 11, and this signal is stored in the storage unit 12. When the value is equal to or larger than the output reference value of 1, the arithmetic processing unit 14 which is a PWM control unit that outputs a signal to the driving unit 13 in which the main circuit unit 2 is constantly turned on is That. The main circuit section 2 is composed of the switching element 6 shown in FIG.

The blower motor 1 is preferably a DC brushless motor which is a permanent magnet type motor or a wound DC motor which is an electromagnet type motor. The signal input unit 11 is an interface IC or the like, and switches input signals and temporarily stores the input signals. Storage unit 12 is a ROM
And a storage device such as a RAM, a magnetic disk, or a punch card. The arithmetic processing unit 14 is a semiconductor device that performs arithmetic processing, such as a microprocessor or a digital signal processor. The drive unit 13 is a gate circuit for driving transistors, FETs, and the like.

The present apparatus having the above configuration operates as follows.

The signal input from the signal input unit 11 is processed by the arithmetic processing unit 14 and determines the ON / OFF duty ratio of the switching element 6 in the PWM control according to the required blower motor output. For example, when the blower motor 1 capable of maximum output when the power supply voltage is 10 (V) is PWM-controlled, and the battery voltage VB is 12 (V), the switching element 6 for maximizing the output of the blower motor 1 is turned on. If the duty ratio is set to about 83% as an ideal value without considering switching loss and the like, the average voltage can be set to 10 (V) and the maximum output of the blower motor 1 can be obtained. In this way, in order to obtain the required output from the blower motor 1, the ON duty ratio of the switching element 6 may be varied so that the average voltage according to the output is applied to the blower motor 1 by PWM control.

Further, the switching operation of the switching element 6 when 80% or more of the output of the blower motor 1 is PWM-controlled cannot be turned off normally because the off time width becomes small. Therefore, the transition loss of the switching loss in the switching element 6 tends to suddenly increase as shown by the broken line in FIG. Therefore, the switching element 6 such that the blower motor 1 outputs 80% or more
When the duty ratio is ON, if the switching element 6 is steadily turned on without PWM control, the above-mentioned transient loss can be reduced.

In this device, the switching 6 is constantly turned on when the duty ratio of the PWM control is 80% or more, but the switching loss tends to increase as the switching frequency of the switching element 6 increases. Therefore, it is desirable that the duty ratio is not always set to 80% or more, but is set to effectively reduce the switching loss according to the switching frequency of the switching element 6 or the switching characteristics of the switching element. Also, the switching frequency is
When the frequency is 500 to 1 kHz or more, the sound generated at the time of switching of the switching element is reduced, but if the switching frequency is too high, the switching loss increases. Therefore, the switching loss or the resonance frequency with the inductance component of the blower motor 1 It is desirable to decide in consideration of such factors.

The switching loss experimented based on this device can be represented by a graph as shown in FIG. The electric power supplied to the blower motor 1 described in the related art is 100
In the graph of the loss in the power control when the control is performed up to%, the solid line is shown up to a duty ratio of 80% in the PWM control and the broken line is shown up to a duty ratio of 80% or more. Further, in the graph of power loss by this device, since PWM control is not performed when the duty ratio is 80% or more, only the ON resistance of the switching element is lost, so that the loss during power control is reduced and the loss becomes constant.

FIG. 3 is a flow chart of control of this apparatus.

When the output of the blower motor 1 is less than 80% (S1), the PW corresponding to the required output of the blower motor 1
The duty ratio of M control is determined (S2), and PWM control is performed. When the output of the blower motor 1 is 80% or more, the switching element 6 is constantly turned on without performing PWM control (S3).

As described above, in the automobile blower control device according to the present invention, the blower motor is PWM-controlled, and when the on-duty ratio of the switching element is 80% or more, the switching element is constantly turned on. It is possible to reduce the switching loss in the transitional period when the element cannot be turned off and increases.

In the above-mentioned embodiment, the automobile blower control device has been described, but the present invention can be variously modified within the scope of the claims. The present invention is
The present invention is not limited to a fan control device for an automobile, but can be applied to a general blower fan motor control device, and more specifically, an automobile cooler,
For example, it can be applied to an automobile fan, an air conditioner condenser, an engine fan air cooler, an electric fan motor that blows air to a torque converter oil cooler, or an air cleaner fan motor.

[0031]

As described above, according to the present invention, in the PWM control, the switching element is constantly turned on when the ON duty ratio of the switching element becomes large. The output of the blower fan motor, the blower motor, and the electric fan motor can be efficiently changed by reducing the output.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a configuration of a blower control device for an automobile, which is an embodiment of the present invention.

FIG. 2 is a graph for explaining a switching loss of a blower control device for an automobile which is an embodiment of the present invention and a switching loss of a conventional device.

FIG. 3 is a flowchart for explaining the control of the automobile blower control device that is an embodiment of the present invention.

FIG. 4 is a drawing for explaining a main circuit portion in a conventional device.

FIG. 5 is a diagram for explaining a main circuit portion in a conventional device and an automobile blower control device that is an embodiment of the present invention.

[Explanation of symbols]

1 ... Blower motor, 2 ... Main circuit part, 3 ...
Switch, 4 ... Variable resistor, 5 ... Diode for surge killer, 6 ... Switching element, 7
... flywheel diode, 11 ... signal input section, 1
2 ... storage unit, 13 ... drive unit, 14 ...
Arithmetic processing unit.

Claims (3)

[Claims] 1. A blower fan motor control device for PWM-controlling a blower fan motor for varying an air volume, a signal input means for processing a signal inputted from the outside, and a predetermined blower fan motor output. According to the signal from the reference value storage means for storing the reference value, the switching means for performing the switching operation of the PWM control of the blower fan motor, the driving means for driving the switching means, and the signal from the signal input means. The duty ratio of ON and OFF in the PWM control is varied according to the required output of the blower fan motor, and when the signal is a value equal to or higher than the output reference value of the blower fan motor stored in the reference value storage means, PWM control means for outputting to the drive means a signal in which the switching means is constantly turned on,
A blower fan motor control device comprising: 2. A vehicle blower control device for PWM-controlling a blower motor for varying the air flow rate of an automobile air conditioner, comprising a signal input means for processing a signal input from the outside, and a predetermined blower motor. Reference value storage means for storing an output reference value, switching means for performing a switching operation of PWM control of the blower motor, driving means for driving the switching means, and PWM according to the signal from the signal input means. The duty ratio of ON and OFF in control is varied according to the required output of the blower motor, and when the signal is a value equal to or higher than the output reference value of the blower motor stored in the reference value storage means, the switching means is switched to the drive means. PWM control means for outputting a signal in which the means is constantly turned on. Automotive blower controller according to symptoms. 3. A motor vehicle electric fan motor control device for PWM-controlling an electric fan motor for varying the amount of air blown to a vehicle cooler, wherein a signal input means for processing a signal input from the outside. A reference value storage means for storing a predetermined output reference value of the electric fan motor, a switching means for performing a PWM control switching operation of the electric fan motor, and a driving means for driving the switching means. The drive means and the duty ratio of ON and OFF in the PWM control according to the signal from the signal input means are varied according to the required output of the electric fan motor, and the signal is stored in the reference value storage means. When the output value of the fan motor is equal to or higher than the reference value, the signal that the switching means is constantly turned on is sent to the driving means. Automotive electric fan motor control apparatus characterized by having a PWM control unit for outputting.