JPH0837795A - Control device of brushless motor - Google Patents

Abstract

PURPOSE:To reduce pull-in time of the phase control by delaying the trigger point so that the trigger point may not coincide with the minimum point of the motor torque ripple to increase the change in the rotation speed. CONSTITUTION:A delay circuit 8h is provided between a waveform shaping circuit 8a and a phase comparator 8c. This delay circuit 8h delays the trigger point for a prescribed period of time so that the trigger point of the phase control may coincide with the maximum point of the motor torque ripple. The phase control signal is transmitted from an adder 8e to a motor drive circuit 8g with this delayed trigger point as the reference, and a drive coil of each phase is energized and controlled by the motor drive circuit 8g. Because the trigger point is delayed so that the trigger point may not coincide with the minimum point of the motor torque ripple, the change in the rotational speed is increased, and the pull-in time of the phase control is reduced thereby.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor controller.

[0002]

2. Description of the Related Art FIGS. 3 and 4 show an example of a conventional brushless motor control device. This brushless motor is a three-phase brushless motor, and reference numeral 1 indicates a rotating shaft, and this rotating shaft 1 is a bearing erected on a circuit board (printed circuit board) 2 as shown in FIG. It is rotatably supported via a bearing 4 in the holder 3.
A substantially cup-shaped rotor case 5 as a rotor that rotates integrally with the rotary shaft 1 is fixed to the upper end portion of the rotary shaft 1 in FIG. 3, and the inner circumference of the outer peripheral flange portion of the rotor case 5 is fixed. An annular rotor magnet 6 is arranged on the surface. The rotor magnet 6 is magnetized with N poles and S poles, which are driving magnetic poles, alternately in the circumferential direction.
A stator core 19 is arranged at a position on the inner peripheral side facing the rotor magnet 6.
A driving coil 10 is wound around the.

A PG magnet 7 is provided on the outer peripheral surface of the rotor case 5 as a magnetizing portion for position detection.
A PG sensor 9 as a position detector is provided on the circuit board 2 at a position facing the outer peripheral surface of the rotor case 5.

A drive IC 8 is mounted on the circuit board 2. As shown in FIG. 4, the drive IC 8 is connected to the output terminal of the PG sensor 9 and has a waveform shaper (amplifier is also available) 8a for shaping the output signal of the PG sensor 9 into a rectangular wave and a reference. A reference clock 8b that generates a reference clock as a signal, a rising point (falling point) that is connected to the output end of the waveform shaper 8a and the reference clock 8b, and serves as a trigger point of the output signal of the waveform shaper 8a. Phase comparator 8 for comparing the phase with the reference clock
c, a low-pass filter 8d connected to the output terminal of the phase comparator 8c, an adder 8e for synthesizing an output signal of the low-pass filter 8d and a frequency control signal, and an output terminal of the adder 8e, The drive coil 10 for each phase so that the trigger point and the reference clock are synchronized.
And a motor drive circuit 8g for controlling energization.

Next, the operation of the brushless motor controller thus constructed will be described below. First, the motor drive circuit 8g energizes the drive coil 10 in a predetermined manner to rotate the rotor magnet 6, the rotor case 5, and the rotary shaft 1. Then, the magnetic field from the PG magnet 7 is detected by the PG sensor 9, and the PG sensor 9 outputs a convex signal having an inclined surface as shown in FIG. This convex portion is generated when the PG magnet 7 crosses the PG sensor 9.

The signal shown in FIG. 5 (a) is input to a waveform shaper 8a, and the waveform is shaped into a rectangular shape in the waveform shaper 8a.
A pulse wave as shown in (b) is output. Rising point of this pulse wave (falling point is also acceptable)
Is the trigger point.

The signal shown in FIG. 5 (b) is input to the phase comparator 8c, and the phase comparator 8c outputs the signal shown in FIG.
A comparison is made with the phase of the reference clock as shown in (f). Here, in this example, since the trigger point of the signal shown in FIG. 5B is detected before the reference clock shown in FIG. 5F, the actual phase is higher than the reference phase. In order to synchronize the actual phase with the reference phase, it is assumed that the motor drive circuit 8g from the adder 8e uses the rising point of the pulse wave as a trigger point to increase the motor rotation speed, and then decreases the phase. A control signal, that is, a phase control signal as shown in FIG. Then, when this phase control signal is input to the motor drive circuit 8g, the drive coil 10 of each phase is energized and controlled by the motor drive circuit 8g, and the actual motor rotation speed is as shown in FIG. 5 (i). become.

Incidentally, FIGS. 5 (a), 5 (b), 5 (f),
The waveform diagram of (e) corresponds to that of each point of a, b, f, and e in FIG.

[0009]

However, the above-mentioned brushless motor control device has the following problems. That is, the minimum point Y of the motor torque ripple and the trigger point of the phase control shown in FIG.
(See (b)) may coincide with each other as shown in FIG. 5, but if the input of the phase control signal of the motor suddenly changes at such a time, the speed response of the motor is delayed and the rotation speed change r is There is a problem that it becomes smaller and the pull-in time t of the phase control becomes longer. In particular, the brushless motor
For example, when it is used as a cylinder motor of a VTR, the pull-in time t of the phase control causes a color shift or disorder of the image screen, which is a problem.

Therefore, an object of the present invention is to provide a controller for a brushless motor in which the speed response of the motor is accelerated, the change in the rotation speed is increased, and the pull-in time of phase control is shortened.

[0011]

In order to achieve the above-mentioned object, a brushless motor control device according to a first aspect of the present invention includes a position detecting magnetizing portion provided on a rotor and a position detecting magnetizing portion opposed to the position detecting magnetized portion. Position detector, a phase comparator that compares the phase of the trigger point and the reference signal in the output signal from this position detector, and based on the output signal of this phase comparator, the trigger point and the reference A motor drive circuit for controlling energization of a drive coil of each phase so that signals are synchronized with each other, in a brushless motor control device, wherein the trigger point and the motor are provided between the position detector and the phase comparator. A delay circuit for delaying the trigger point is provided so that the minimum point of the torque ripple does not match.

In order to achieve the above object, the control device for a brushless motor according to a second aspect of the present invention is, in addition to the first aspect of the present invention, a delay circuit, in which the trigger point is set so as to match the maximum point of the motor torque ripple. It was supposed to be delayed.

[0013]

In the brushless motor control device according to the first means, the delay circuit prevents the phase control trigger point and the motor torque ripple minimum point from matching. Therefore, the speed reaction of the motor is accelerated with respect to the change of the phase control signal to the motor, the change of the rotation speed is increased, and the pull-in time of the phase control is shortened.

According to the brushless motor control device in the second means, the delay circuit causes the trigger point for phase control to coincide with the maximum point of the motor torque ripple. Therefore, the speed reaction of the motor becomes the fastest with respect to the change of the phase control signal to the motor, the change of the rotation speed becomes the maximum, and the pull-in time of the phase control is shortened to the maximum.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a brushless motor controller according to an embodiment of the present invention, and FIG. 2 is a timing chart for explaining the circuit operation shown in FIG. Are denoted by the same reference numerals, and description thereof is omitted here to avoid duplication.

The brushless motor of this embodiment is used as a VTR cylinder motor, as in the prior art. The brushless motor control device of this embodiment is different from that of the prior art in that a delay circuit 8h is provided between the waveform shaper 8a and the phase comparator 8c.
This delay circuit 8h delays the trigger point of the phase control for a predetermined time so that the trigger point coincides with the maximum point X of the motor torque ripple.

Therefore, from the PG sensor 9, as shown in FIG.
A convex signal having an inclined surface as shown in Fig. 2 is output, and the signal shown in Fig. 2 (a) is input to the waveform shaper 8a, and the waveform is shaped into a rectangular shape in the waveform shaper 8a. Then, the waveform shaper 8a outputs a pulse wave as shown in FIG. 2 (b). So far,
2 (b) is input to the delay circuit 8h, and the signal shown in FIG. 2 (b) is delayed by a predetermined time in the delay circuit 8h.
As shown in FIG. 2 (g), the delay circuit 8h outputs the phase control trigger point as a signal that coincides with the maximum point X of the motor torque ripple.

Then, the phase of the signal at which the trigger point of this phase control coincides with the maximum point X of the motor torque ripple is compared with the reference clock, and the delayed trigger point is used as a reference for the motor from the adder 8e. A phase control signal as shown in FIG. 2 (e) is sent to the drive circuit 8g. When this phase control signal is input to the motor drive circuit 8g, the drive coil 10 of each phase is energized and controlled by the motor drive circuit 8g, and the actual motor rotation speed is such that the speed response of the motor becomes the fastest. From that, it becomes as shown in FIG. That is, FIG.
As is clear from (i), the rotation speed change R is larger (actually maximum) than the rotation speed change r of the prior art, and the pull-in time T of the phase control is shorter than the pull-in time t of the prior art (actually). shortest).

As described above, in this embodiment, the delay circuit 8h causes the phase control trigger point and the maximum point X of the motor torque ripple to coincide with each other, so that the phase control signal to the motor changes. On the other hand, the speed response of the motor is the fastest and the change in the rotation speed is the maximum, and the pull-in time of the phase control can be shortened to the maximum. Therefore, it is possible to improve the color shift and the disorder of the video screen.

By the way, the applicant of the present invention applied to the rotation detecting device for the brushless motor described above to improve the speed response of the motor, that is, to shorten the pull-in time of the phase control, by changing the stator core, the drive magnetic pole part, The setting is performed by setting the relative positions of the FG magnetized portion and the FG pattern in the circumferential direction. However, in such a case, it is necessary to consider the external shape of the motor and the problem of mounting. However, in this embodiment, since the pull-in time of the phase control is shortened by the circuit, it is not necessary to take such a consideration into consideration, and in some cases, the device can be made smaller than the previous application device. There are advantages.

Although the invention made by the present inventor has been specifically described based on the embodiments, the invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say, for example, in the above-described embodiment, the delay circuit 8h is used to match the trigger point for phase control with the maximum point X of the motor torque ripple, but the present invention is not limited to this. In addition, the trigger point may be delayed so that the trigger point does not coincide with the minimum point Y of the motor torque ripple. Even in this case, the speed reaction of the motor becomes faster and the change in the rotation speed becomes larger than in the conventional case, and the pull-in time of the phase control can be improved.

Further, in the above embodiment, the delay circuit 8
Although h is connected between the waveform shaper 8a and the phase comparator 8c, it is connected between the PG sensor 9 and the waveform shaper 8a to delay the signal shown in FIG. 2 (a). Even if it does, the same effect can be obtained.

Furthermore, in the above embodiment, VT
Although the application example to the R cylinder motor is described, it goes without saying that the invention can be applied to other than the VTR cylinder motor.

[0024]

As described above, according to the brushless motor control device of the first aspect of the present invention, the delay circuit causes the phase control trigger point and the minimum point of the motor torque ripple not to coincide with each other. The speed reaction of the motor becomes faster with respect to the change of the control signal, the change of the rotation speed becomes large, and the pull-in time of the phase control can be shortened.

Further, according to the brushless motor control device of the second aspect of the present invention, the delay circuit causes the trigger point of the phase control and the maximum point of the motor torque ripple to coincide with each other. , The speed reaction of the motor becomes the fastest, and the change in rotation speed becomes the maximum,
It is possible to shorten the pull-in time of the phase control to the maximum.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a brushless motor control device according to an embodiment of the present invention.

FIG. 2 is a timing chart for explaining the circuit operation shown in FIG.

FIG. 3 is a lateral cross-sectional view of a main part of a brushless motor control device showing a conventional technique.

FIG. 4 is a block diagram showing a configuration of a controller of the brushless motor shown in FIG.

5 is a timing chart for explaining the circuit operation shown in FIG.

[Explanation of symbols]

 1,5 Rotor 7 Position detecting magnetizing unit 8b Reference clock 8c Phase comparator 8g Motor drive circuit 8h Delay circuit 9 Position detector 10 Drive coil X Maximum point of motor torque ripple Y Minimum point of motor torque ripple

Claims (2)

[Claims] 1. A position detecting magnetized portion provided on a rotor, a position detector arranged to face the position detecting magnetized portion, and a trigger point in an output signal from the position detector. A phase comparator that compares the phase with a reference signal, and a motor drive circuit that controls energization of the drive coils of each phase so that the trigger point and the reference signal are synchronized based on the output signal of the phase comparator. In the controller of the brushless motor, the delay device for delaying the trigger point is provided between the position detector and the phase comparator so that the trigger point does not match the minimum point of the motor torque ripple. Brushless motor controller. 2. The brushless motor control device according to claim 1, wherein the delay circuit delays the trigger point so that the trigger point coincides with the maximum point of the motor torque ripple.