JP3485686B2 - Abnormal control device for rotation speed of DC brushless motor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC brushless motor, and more particularly to a rotation speed abnormality control device for a DC brushless motor suitable for a small fan motor for blowing air.

[0002]

2. Description of the Related Art FIGS. 6 to 7 are views showing the configuration and operation of a conventional rotation speed abnormality control device for a DC brushless motor.
As shown in FIG. 6, the signal from the magnetic pole detection element 4 for detecting the magnetic pole position of the permanent magnet rotor of the DC brushless motor is input to the microcomputer 1 through the amplifier 6, and the energization signal is output from the microcomputer 1 to drive the motor. A current is passed through one of the stator windings 2 via the drive circuit 3. Similarly, a signal input to the microcomputer 1 via the amplifier 7 outputs an energization signal delayed in phase from the microcomputer 1, and a current delayed in phase is supplied to the other stator winding 2. Now, when an abnormality occurs in the rotation speed due to a load fluctuation or the like, the microcomputer 1 detects the rotation speed abnormality and outputs an output of the rotation speed abnormality, and as shown in FIG. A large amount of current is applied and a small amount of current having a time width T4 or non-energization is alternately repeated to perform restarting energization, and then a normal return current is applied to restore normal rotation.

[0003]

However, in such a conventional DC brushless motor rotation speed abnormality control device, as shown in FIG. 7, the restart energization for intermittently supplying a pulsed large current is repeated. Since it is repeatedly performed, there is a problem in that it is disadvantageous in terms of protection of the semiconductor element of the motor drive circuit 3.

The present invention has been made in order to solve the above-mentioned problems, and the rotation speed abnormality control of a DC brushless motor which surely protects a semiconductor element of a motor drive circuit and surely restarts the motor when returning to a normal state. The purpose is to provide a device.

[0005]

To achieve this object, in the DC brushless motor rotation speed abnormality control device of the present invention, as shown in FIG. 1, the magnetic pole position of the permanent magnet rotor of the DC brushless motor is set. A magnetic pole detecting element for detecting, a rotational speed calculating means for calculating the rotational speed of the permanent magnet rotor from the output of the magnetic pole detecting element, and a rotational speed anomaly in which the rotational speed is a preset rotational speed threshold value. When the delay time is exceeded, a rotation speed abnormality detecting means for determining a rotation speed abnormality and a small current is passed through the stator winding of the brushless motor after detecting the rotation speed abnormality, and then the rotation speed is preset. A restart energizing means for energizing a pulsed large current with a constant time width only when the normal return speed threshold value is exceeded,
After that, further provided is a normal return energizing means for supplying a normal return current when the rotational speed threshold value is again exceeded.

Further, a rotation speed abnormality determination threshold value setting means capable of arbitrarily setting the rotation speed threshold value for determining the rotation speed abnormality, or an energization time of the pulsed large current for the restart energization is arbitrary. The delay time setting means capable of setting the normal return rotation speed threshold value setting means for setting the normal return rotation speed threshold value for determining the normal return rotation speed can be arbitrarily set.

In this DC brushless motor rotation speed abnormality control device, as shown in FIG. 2, the magnetic pole detection element detects the magnetic pole position of the permanent magnet rotor, and the rotation speed calculation means permanently changes the output of the magnetic pole detection element. The rotation speed of the magnet rotor is calculated, and it is determined whether or not the rotation speed abnormality detecting means exceeds a preset rotation speed threshold value. If it exceeds, a small current is passed after a delay time of T2 time. Then, it is determined whether or not the preset threshold value for normal speed of rotation is exceeded, and only when the threshold value is exceeded, restart energization is performed in which a large pulsed current for T2 is passed. After that, when the rotation speed threshold value is again exceeded, by supplying a normal recovery current with the normal recovery energizing means, the normal speed can be recovered. If the return to normal speed is unsuccessful, it automatically returns to the original state.
The restart energization is repeated to reliably restore the normal rotation speed. In this way, the restart energization involving the pulsed large current can be suppressed to the necessary minimum without performing the unnecessary repetition many times as in the conventional technique.

Further, the rotation speed abnormality determination threshold value setting means can set an appropriate rotation speed threshold value for surely returning to normal. Alternatively, since the energizing time of the pulsed large current can be appropriately set by the delay time setting means, effective restart energization and normal recovery energization are possible. Alternatively, since the normal return determination rotation speed threshold value setting means can appropriately set the normal return rotation speed threshold value,
Furthermore, it can be suppressed to the minimum necessary.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 3 to 4 are explanatory views of an embodiment of a rotation speed abnormality control device for a DC brushless motor according to the present invention. As shown in FIG. 4, the output of the magnetic pole detection element 4 is input to the microcomputer 1 via the amplifier 6,
The rotation speed is calculated by the rotation speed calculation means 8 mounted in
From the rotation speed and the rotation speed abnormality threshold value input from the rotation speed abnormality determination threshold value setting means 12, the rotation speed abnormality detecting means 9 determines the rotation speed abnormality.

Next, the rotation speed abnormality signal indicates the restart energizing means 1
When it is input to 0, as shown in FIG. 5, after a delay time of T2 set by the delay time setting means 13, a small current is supplied. After that, when the normal return rotation speed threshold value set by the normal return determination rotation speed threshold value setting means 14 is exceeded, the restart energization means 10 applies the pulsed large current for the above-mentioned T2 time to the restart energization. Is done. After that, when the speed threshold value is exceeded again,
The normal return energization means 11 performs normal return energization, and can return to the normal rotation speed. If the normal rotation speed restoration is unsuccessful, it automatically returns to the original state, so that the restart energization is repeated to reliably perform the normal rotation speed restoration.
Due to the above restart energization, the normal rotation speed is restored without repeatedly performing unnecessary restart energization as shown in the prior art of FIG. 7, and the semiconductor element of the motor drive circuit 3 is restored. A reliable restart can be performed without penalizing the protection of.

[0011]

As described above, the DC according to the present invention
In the rotation speed abnormality control device for a brushless motor, the restart energization with a pulsed large current can be suppressed to the necessary minimum without needlessly repeated many times. It can be surely performed, and the motor can be surely restarted when returning to the normal condition.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to a claim of the present invention.

FIG. 2 is a flowchart of the present invention.

FIG. 3 is a control device as an embodiment of the present invention.

FIG. 4 is an explanatory diagram of an embodiment of the present invention.

FIG. 5 is an explanatory diagram of changes over time in the rotation speed and the energization current.

FIG. 6 is a prior art control device.

FIG. 7 is an explanatory diagram of changes over time in the number of revolutions and the energization current of the conventional technique.

[Explanation of symbols]

1 Microcomputer 2 Stator winding 3 Motor drive circuit 4 Magnetic pole detection element 6 amplifier 7 amplifier 8 Rotation speed calculation means 9 Rotation speed abnormality detection means 10 Restart energizing means 11 Normal return energizing means 12 Rotation speed abnormality determination threshold value setting means 13 Delay time setting means 14 Normal return determination rotation speed threshold value setting means

Continuation of the front page (56) Reference JP-A-1-255432 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H02P 6/08

Claims (4)

(57) [Claims] 1. A magnetic pole detection element for detecting a magnetic pole position of a permanent magnet rotor of a DC brushless motor, a rotation speed calculation means for calculating a rotation speed of the permanent magnet rotor from an output of the magnetic pole detection element, and the rotation. When the number exceeds a preset rotation speed threshold value for a certain rotation speed abnormality delay time, a rotation speed abnormality detecting means for discriminating a rotation speed abnormality, and a small current is detected after detecting the rotation speed abnormality. It is applied to the stator winding of the brushless motor, and then only when the rotation speed exceeds a preset normal rotation speed threshold value, a restarting energizing means for energizing a pulsed large current of a certain time width, and then further A normal rotation energizing means for supplying a normal return current when the rotational speed threshold value is exceeded again, and a rotation speed abnormality control device for a DC brushless motor. 2. The rotation of the DC brushless motor according to claim 1, further comprising rotation speed abnormality determination threshold value setting means capable of arbitrarily setting the rotation speed threshold value for determining the rotation speed abnormality. Number abnormal control device. 3. The rotation speed abnormality control of the DC brushless motor according to claim 1, further comprising a delay time setting means capable of arbitrarily setting a conduction time of the pulsed large current for the restart conduction. apparatus. 4. A normal-return determination rotation speed threshold value setting means capable of arbitrarily setting the normal-return rotation speed threshold value for judging the normal return rotation speed.
2. A rotation speed abnormality control device for a DC brushless motor as described in 2 and 3.