JP2696394B2 - Blower motor controller for automotive air conditioner - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a blower motor control device for an air conditioner for a vehicle, and more particularly, to preventing noise caused by a resonance phenomenon of vibration generated when the motor rotates.

(Prior Art) In recent years, as the life of automobiles has been prolonged, the demand for quietness in the passenger compartment has increased more than ever, and blower motors have also been considered as noise generation sources. . However, as long as a conventional motor having a brush is used, there is a limit to the reduction in noise level due to its structure. For this reason, brushless motors, which are recently being reduced in size and cost, have come to be used as blower motors. As prior art for preventing noise due to vibration generated when the brushless motor rotates,
For example, as shown in Japanese Utility Model Application Laid-Open No. 62-152695,
2. Description of the Related Art There has been known a device in which the fall of a current flowing through a winding of a motor when a motor vibration transistor is turned off is made gentle, and noise is suppressed by vibration generated in a stator block at the time of current switching.

(Problems to be Solved by the Invention) According to the above-described conventional example, the fall of the current flowing through the winding of the motor is made gentle, that is, the change of the magnetic flux is made gentle. Although the noise due to the vibrations generated can be suppressed as small as possible, the noise due to the resonance phenomenon that occurs when, for example, the rotational speed of the motor coincides with the natural resonance frequency of a certain component cannot be suppressed. Therefore, this type of noise prevention device was incomplete.

In view of the above, an object of the present invention is to provide a blower motor control device for an air conditioner for an automobile, which is capable of suppressing noise caused by a resonance phenomenon occurring when the blower motor rotates, in order to solve the above-described problems of the conventional example. It is.

(Means for Solving the Problems) In the blower motor control device for an air conditioner for a vehicle according to the present invention, as shown in FIG. 1, a three-phase exciting coil is wound to generate a rotating magnetic field. And the stator
Rotation determining means 100 for determining the rotational speed of the blower motor 1 having a rotor that rotates with the rotating magnetic field generated in the stator; and energizing timing determining the energizing timing for each exciting coil of the blower motor 1 Means 110, an output signal forming means 120 for forming a plurality of output signals based on an output signal of the rotational speed determining means 100 and an output signal of the energizing timing determining means 110, and the output signal forming means 120. A blower motor control device for an air conditioner for a vehicle, comprising: a drive unit 130 that controls a current flowing through the exciting coil based on the plurality of output signals to drive the blower motor 1. Signal disturbing means 14 for changing the waveform of one output signal periodically or irregularly
0 has been provided.

As the signal disturbing means 130, there is a means for making at least one waveform of an output signal different from others, or a means for making at least one voltage of an output signal different from others.

Further, as shown in FIG. 2, the blower motor control device for an automotive air conditioner according to the present invention includes a stator in which a three-phase excitation coil is wound to generate a rotating magnetic field, and a rotation generated in the stator. Rotation determining means 100 for determining the rotation speed of the blower motor 1 having a rotor that rotates with a magnetic field; energizing timing determining means 110 for determining the energizing timing to each exciting coil of the blower motor 1; An output signal forming unit 120 that forms a plurality of output signals based on the output signal of the number determining unit 100 and the output signal of the energization timing determining unit 110, and a plurality of output signals formed by the output signal forming unit 120. A blower motor control device for an air conditioner for a vehicle, comprising: a driving means for controlling a current flowing through the exciting coil to drive the blower motor. Fraud and mitigating risk rise time of at least one output signal is supplied to the driving means 130, in providing the timing disturbing means 150 for changing regularly or irregularly.

(Operation) Therefore, at least one of the output signals formed by the output signal forming means 120 based on the output signals of the rotation determining means 100 and the energizing timing determining means 110 is output by the signal disturbing means 140 or the timing disturbing means 150. The rotation state of the blower motor can be periodically or irregularly disturbed by disturbing it regularly or irregularly.Therefore, a steady generation state of a specific vibration frequency that causes resonance without greatly changing the rotation speed of the blower motor. Therefore, the above problem can be achieved.

(Embodiment) Hereinafter, an embodiment of a blower motor control device for an automotive air conditioner according to the present invention will be described with reference to the drawings.

As shown in FIG. 3, the present apparatus has a configuration in which a microcomputer 5 controls a three-phase inverter circuit 9 for supplying a drive current to an excitation coil 1a of a blower motor.

The blower motor 1 is for driving a sirocco fan (not shown) disposed upstream of an air conditioning duct (not shown), and uses a brushless motor. Although not shown, this brushless motor is a known motor comprising a rotor composed of a permanent magnet, a fixed winding for generating a rotating magnetic field, a Hall element, etc., and does not need to have a special configuration in the present apparatus. It is.

Reference numeral 2 denotes a speed setting device for setting the rotation speed of the blower motor 1, which is achieved by using a variable resistor. The output voltage taken by the vibrator 2a of the speed setting device 2 is converted into a digital signal by the A / D converter 3 and then input to the microcomputer 5.

Reference numerals 4a to 4c denote Hall ICs provided inside the brushless motor constituting the blower motor 1 for detecting switching positions of the rotor magnetic poles. The Hall ICs 4a to 4c are configured to output TTL level pulse signals in accordance with the direction of the magnetic field. In the embodiment, the rotor (shown in FIG. ) Are provided at an electrical angle of 120 degrees in the vicinity of the output signal Hu, Hv, and Hw, and the output signals Hu, Hv, and Hw are directly input to the microcomputer 5.

The A / D converter 6 is connected so as to convert a power supply voltage value of the DC power supply 7 of the present apparatus into a digital value and output the digital value to the microcomputer 5.

The microcomputer 5 has a central processing unit CPU, a read-only memory ROM, a random access memory RAM, an input / output port I / O, and the like, and is known per se. The microcomputer 5 generates a timing signal as shown in FIG. 4 necessary for controlling the excitation timing of the brushless motor, as is well known, based on the detection signals of the Hall ICs 4a to 4c. Waveform shaping circuits 8a to 8h connected to the output side by a predetermined program described later
Some of them play a role of controlling the drive of the blower motor 1 by changing the waveform, level and the like of the input signal to the three-phase inverter circuit 9 via 8c.

The waveform shaping circuits 8a to 8c connected between the microcomputer 5 and the three-phase inverter circuit 9 generate input signals necessary for the three-phase inverter circuit 9 based on a control signal from the microcomputer 5. Things,
Both have the same configuration.

The three-phase inverter circuit 9 includes a blower motor excitation coil 1a.
And a well-known configuration using transistors.

Thus, in the above configuration, when the DC power supply 7 is applied and the microcomputer 5 starts operating, a signal is applied to the three-phase inverter circuit 9 from the waveform shaping circuits 8a to 8c according to the speed setting device 2, and the excitation coil 1a And the blower motor 1 starts rotating. The microcomputer 5 controls the operation timing of the three-phase inverter circuit 9 based on the input signals Hu, Hv, Hw of the Hall ICs 4a to 4c,
The blower motor 1 is maintained at a predetermined rotation speed.

When the blower motor is driven, the waveform shaping circuits 8a to 8c output the waveform shown in FIG. 5A from the waveform shown in FIG. 5A to the waveform shown in FIG. Change the signal waveform. That is, although each phase has a sine waveform in FIG. 10A, only a V phase (output lines of the waveform shaping circuits 8a to 8c) outputs a square wave signal in FIG.

Further, instead of changing the waveform as described above, for example, the voltage of the W phase is changed from the waveform shown in FIG. 6A to the waveform shown in FIG. Is also good.

Further, instead of the above two examples, the rising timing of the U-phase may be changed from the rising timing shown in FIG. 7A to the rising timing as shown in FIG. Alternatively, the three-phase coil circuit 9 may be driven.

In addition, as a method of changing irregularly, there is a method of generating a random signal and executing the disturbance control every time the random signal matches a predetermined value, and as a method of changing periodically, There is a method in which a counter is provided and disturbance control is performed each time the counter reaches a predetermined value.

Next, in the second embodiment, the same components as those in the above-described first embodiment will be denoted by the same reference numerals with reference to FIGS. 8 to 10, and the description thereof will be omitted. explain.

First, this embodiment uses PWM control which is generally well-known as a control method of an inverter circuit. From the viewpoint of minimizing power consumption in the three-phase inverter circuit 9, the elements constituting the circuit 9 include a power MOSFET. The difference from the first embodiment is that a FET is used.

The flowchart of FIG.
Is a control example in a case where the pulse width is changed irregularly in the PWM control according to the above to energize the excitation coil 1a of the blower motor. The control content will be described with reference to the same figure. The microcomputer 5 starts execution from step 200 and proceeds to step 202, where the microcomputer 5 sends the set speed Sp set by the speed setter 2 to the A / D converter 3. To enter through.

After the processing of step 202, the process proceeds to step 204, where the power supply voltage
The V ₁ and input through the A / D converter 6, the process proceeds to step 206.

In step 206, the calculation of the pulse width T in the PWM control is performed by the following equation (1).

Here, Sp is the set speed input in step 202 described above, V ₁ is the power supply voltage input in step 204 described above, K
Is an operation count.

In step 208, a random number is generated, and the process proceeds to step 210. In step 210, it is determined whether or not the random number generated in step 208 is equal to a predetermined value y. When the generated random number is equal to the predetermined number y (YES), the process proceeds to step 212, the timer for a predetermined time (for example, about 1/1000 second) is operated, and after the lapse of time, the process returns to step 202, and the above-described processes are performed. It will be repeated.

On the other hand, if the generated random number is not equal to the predetermined value y (NO), the process proceeds to step 214, where the detection signals Hu, from the Hall ICs 4a to 4c are detected.
Enter Hv and Hw. After the processing in step 214, the processing in steps 216 to 226 described below is performed.

In FIG. 9, the steps after step 216 are described in parallel to indicate that basically the same processing is performed for each phase, but actually, the processing is performed by serial processing.

First, in step 216, it is determined whether or not Hu is “1”. If Hu = 1 (YES), the process proceeds to step 218, and the square synchronized with sin θ with the pulse width T calculated in step 206 described above. The wave signal is output to the U-phase (U + or U− side in FIG. 8) of the three-phase inverter circuit 9, and thereafter, the process returns to step 202 and the above-described processing is repeated again.

On the other hand, if Hu = 1 is not satisfied (NO), the above-described step 21 is performed.
Skip to step 8 and return to step 202 described above.

Next, in step 220, it is determined whether or not Hv is “1”. If Hv = 1 (YES), the process proceeds to step 222,
As in step 218, sin (θ−2 / 3π) with pulse width T
Is output to the V phase (V + or V− side in FIG. 8) of the three-phase inverter circuit 9. Then, after the processing of step 222 or in step 220, Hv is “1”.
If not (NO), the process returns to step 202.

Further, in step 224, it is determined whether or not Hw is “1”. If Hw = 1 (YES), the process proceeds to step 226, and sin (θ−3 / 4) with the pulse width T as in step 218.
π) is synchronized with the W signal of the three-phase inverter circuit 9.
It is output to the phase (W + or W− side in FIG. 8). And
After the processing in step 226 or in step 224, Hw is “1”.
If not (NO), the process returns to step 202.

As a result, a square wave signal synchronized with a sine wave as shown in FIG. 10 (a) is applied to the excitation coil 1a of the blower motor by the control program,
The pulse width of each square wave signal will always change unless the random number reaches a predetermined value.

As shown in FIG. 10 (b), instead of averaging the excitation coil applied voltage by the PWM control as described above, the sine waveform shown in FIG. 10 (a) is used. A constant average voltage may be obtained by performing duty ratio control.

Finally, the third embodiment will be described below with reference to the flowchart of FIG. 11 while referring to differences from the above-described second embodiment. Steps having the same contents as the processing in the flowchart of FIG. 9 are denoted by the same reference numerals, and description thereof is omitted.

The second embodiment differs from the second embodiment in that the pulse width T is changed randomly, whereas the third embodiment is changed periodically. For this reason, in step 207, “1” is added to the variable F for counting and the flow proceeds to the next step 209.

In step 209, it is determined whether or not the variable F has reached the predetermined value x. If F = x (YES), the process proceeds to step 212, where the variable F is returned to "1" after the lapse of the timer time, and Return to 202.

On the other hand, if it is determined in step 209 that the variable F has not yet reached x (NO), the process proceeds to step 214.

Thus, according to this embodiment, until the variable F reaches the predetermined value x, the PWM control is performed with the pulse width T every time step 206 is executed, and when the variable F reaches the predetermined value x, the PWM control is performed. The motor drive by the pulse width T in the previous processing is maintained for the time.

(Effects of the Invention) Since the present invention is configured as described above,
It is avoided that the same vibration frequency is always generated, and noise generation due to resonance can be suppressed.

Further, since noise generation due to resonance is electrically suppressed, a mechanical device such as a vibration-proof material or a sound-proof cover is not required, and the size and cost of the device can be reduced.

Furthermore, in the past, where resonance points often differed slightly for each device, the countermeasures were individually different, and unified countermeasure work could not be performed, resulting in an increase in the number of assembly steps. According to this, there is an effect that it is possible to easily cope with a change in the program.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of a blower motor control device for an air conditioner for a vehicle according to the invention of claim 1, and FIG.
FIG. 3 is a functional block diagram of a blower motor control device for a vehicle air conditioner according to the present invention, FIG. 3 is a circuit diagram showing a first embodiment, and FIG. 4 is a diagram showing detection waveforms of Hall ICs in the circuit shown in FIG. FIGS. 5 to 7 are timing charts showing the relationship with the switching timing of the three-phase inverter circuit, FIGS. 5 to 7 are waveform diagrams showing output signals of a waveform shaping circuit used in the circuit in FIG. 3, and FIG. FIG. 9 is a circuit diagram showing an embodiment. FIG. 9 is a flowchart showing an example of drive control of a blower motor in a microcomputer used in the second embodiment.
FIG. 10A is a waveform diagram of the applied voltage of the exciting coil of the blower motor in the second embodiment, FIG. 10B is a waveform diagram showing another example of the applied voltage of the exciting coil, and FIG. 4 is a flowchart illustrating an example of drive control of a blower motor. 1a: Exciting coil of blower motor, 2: Speed setting device,
5: microcomputer, 8a to 8c: waveform shaping circuit, 100: rotation determining means, 110: energizing timing determining means, 120: driving means, 130: signal disturbing means, 140 ...
... timing disturbing means.

Claims (2)

(57) [Claims] 1. A rotation determining means for determining a rotation speed of a blower motor having a stator in which a three-phase excitation coil is wound to generate a rotating magnetic field, and a rotor rotating with the rotating magnetic field generated in the stator. Energizing timing determining means for determining energizing timing to each exciting coil of the blower motor; forming a plurality of output signals based on an output signal of the rotational speed determining means and an output signal of the energizing timing determining means. Blower motor control for a vehicle air conditioner, comprising: output signal forming means; and driving means for controlling a current flowing through the exciting coil based on a plurality of output signals formed by the output signal forming means to drive the blower motor. In the apparatus, the waveform of at least one output signal supplied to the driving unit is changed periodically or irregularly. A blower motor control device for an air conditioner for an automobile, comprising a signal disturbing means for causing the signal to be disturbed. 2. A rotation determining means for determining a rotation speed of a blower motor having a stator around which a three-phase excitation coil is wound to generate a rotating magnetic field, and a rotor rotating with the rotating magnetic field generated at the stator. Energizing timing determining means for determining energizing timing to each exciting coil of the blower motor; forming a plurality of output signals based on an output signal of the rotational speed determining means and an output signal of the energizing timing determining means. Blower motor control for a vehicle air conditioner, comprising: output signal forming means; and driving means for controlling a current flowing through the exciting coil based on a plurality of output signals formed by the output signal forming means to drive the blower motor. In the apparatus, the rising timing of at least one output signal supplied to the driving unit is periodically or indefinitely determined. A blower motor control device for an air conditioner for an automobile, wherein a timing disturbing means for changing the period is provided.