JPS61157250A - Drive detector circuit for brushless motor - Google Patents

Abstract

PURPOSE:To set a rotating angular velocity constantly by disposing a plurality of position detecting Hall elements as prescribed, thereby eliminating the irregular rotation. CONSTITUTION:The 1st-3rd stator coils 2-4 of a stator 1 and Hall elements 24-28 disposed on the coils are arranged at the center of coils 2a, 2b, 3a, 4a, 4b as shown, Hall elements 34, 26 are disposed at an interval of 120 deg., and other Hall elements 27, 25, 28 are disposed at an equal interval of 60 deg. on the same circumference. Further, since a current is flowed to a circuit designated, for example, by a broken line between the rotating angles 0 deg. to 15 deg. to shortcircuit the elements 24-28, it is prevented by resistors R1, R2. Thus, the position of the rotor is detected, the 1st-3rd stator coils 2-4 are selectively energized through a control circuit to smoothly rotatably drive without torque ripple (variation in the rotating angular velocity).

Description

[Detailed Description of the Invention] [Technical Field] This invention detects the rotor position of a brushless motor using a magnetically sensitive element, controls a current switching element (transistor) by a control circuit, and selects a stator coil. This invention relates to a device that rotates a rotor by supplying an energizing current, and in particular, to a drive detection circuit for a brushless motor that maintains a constant rotational angular velocity and achieves smooth rotation by appropriately arranging magnetically sensitive elements. be.

[Prior art]

This kind of brushless motor is used as a drive motor for computer automatic equipment and various electronic equipment, such as:
For floppy disk motors, direct-coupled drives, which require sufficient torque and small changes in rotational speed, have become popular.

The conventional examples shown in FIGS. 3, 4, and 5 will be explained. In FIGS. 3(a) and (b), 1 indicates six stator coils (for example, clockwise It is assumed that the stator wire is wound in the following manner:
A first stator coil 2 and a second stator coil 3 (serial coils 3a, 3b) each having a series coil 2a, 2b arranged in the force direction 18(f') with respect to the center of the base. A third stator coil 4 (series coils 4a, 4b) is formed.First, second.

The third stator wire rings 2, 3.4 are star-connected and form a six-pole stator 1. Further, in FIG. 4, a rotor 5 is made of a permanent magnet having eight magnetized magnetic poles, and is configured to face the stator 1 with an air gap 6 in between.

7 is a rotating shaft, and its bearing 8 is attached to the base of the stator 1.

In FIG. 5, 9 is a brushless morph control circuit (I
C) shows an internal schematic diagram. 9a is a position detection function circuit, 10, 11, 12°i3, 14.15
is a terminal. 16.17 is a control input terminal, 18 is a forward/reverse switching terminal, 19 is a power supply terminal, 20, -21
, 22 are input/output terminals of the first, second and third stator coils 2, 3.4, and 23 is a power supply terminal. In addition, 24th, 25th,
26 is a magnetic sensing element (for example, a Hall element or the like).
(hereinafter referred to as a Hall element), and each stator coil 2a.

These three Hall elements 24, 25, 26 detect the position of the rotor 5 and connect the terminals 10, 11, ,12,
Output voltage at 13, 14, and 15. This Hall element signal, the control input to terminals 16 and 17, and the forward/reverse input to terminal 18 pass through the control circuit (rc) 9 to the current switching element 9.
b (transistor) is activated to open and close the power supply voltage from the terminal 19, thereby controlling the energization to the first, second, and third stator coils 2.3.4.

In this configuration, three Hall elements 24, 25, 26
The outputs of are input to terminals 10, 11, 12, 13, 14, and 15. At this time, the output of the Hall element is normal +,
For one direction (hereinafter referred to as forward direction), terminals 10 and 12
．． Ten voltages are applied to terminals 14 and one voltage is applied to terminals 11, 13, and 15. When the output of the Hall element is -, which is referred to as a trend below the ten force direction, ten voltage is applied to terminals 11, 13, and 15, and terminal 1 is
One voltage is applied at 0°12.14. Now, for example,
The relationship with the magnetic poles of the rotor 5 is the first stator wire 2 (2a, 2
b) Opposed to N pole, second stator coil 3 (3a, 3b)
It is assumed that the S pole is opposite to the stator coil 4, and the N pole is opposite to the third stator coil 4 (4a, 4b). Hall elements 24, 25, 26
detects the magnetic pole and applies forward voltage to input terminals 10 and 11, reverse voltage to input terminals 12 and 13, and forward voltage to input terminals 14 and 15, respectively.

Therefore, by logic, 1. Q becomes 1, the control circuit (IC) 9 is activated by the logic circuit, and the output side current switching element 9b is activated.
Kazumi Kazumi's goo 1 is activated 7, and power supply voltage is applied from the input terminal 20 to the first stator coil 2 (2a, 2b) from the power supply terminal 19, and current flows to the second stator coil 3. (3a,
3b), the output terminal 21, and the second fixed wire ring 3(3a
, 3b) from the gate of the output side current switching element to the power supply terminal 23 (third stator coil 4 (4a, 4
The gate of the output transistor corresponding to b) is not activated). In this way, the position of the magnetic pole of the rotor 5 is detected by the Hall elements 24, 25, 26c, and the first stator wire 62 (2
a, 2b) and the second stator wire wheels 3 (3a, 3b) in the forward direction (+ direction, hereinafter referred to as "forward direction") and reverse direction (one direction, hereinafter referred to as "reverse direction") to rotate. Due to the magnetic action between the child 5 and the stator 1, the rotor 5 rotates clockwise (to the right, hereinafter referred to as "clockwise") from a rotation angle of 2 to 1.

Next, during the rotation angle from 1 to 3, the Hall element 24
, 25.26 corresponds to N pole, S pole, and S pole in logic 1.0. It becomes O.

Therefore, the first stator coil 2 (2a, 2b) is directed in the forward direction.
The third stator wire wheels 4 (4a, 4b) are biased in opposite directions, and the rotor 5 rotates clockwise from a rotation angle of 1 da to 3 Cf.

Next, during the rotation angle from 3C to 4Da, the Hall element 24
, 25.26 correspond to N pole, N pole, and S pole in logic 1.1. It becomes O.

Therefore, the second stator coil 3 (3a, 3b) is directed in the forward direction.
The third stator coils 4 (4a, 4b) are biased in opposite directions.

Next, during the rotation angle from 4 de to 6 ff', the Hall elements 24, 25, and 26 have logic values of 0.1.0 corresponding to the south pole, north pole, and south pole.

Therefore, the second stator coil 3 (3a, 3b) is directed in the forward direction.
The first stator coils 2 (2a, 2b) are each biased in opposite directions.

Next, from rotation angle 6 (F to 7 cf'), the Hall elements 24, 25.25 are 0.1.1 in logic, corresponding to the S pole, N pole, and N pole.

Therefore, the third stator coil 4 (4a, 4b) is directed in the forward direction.
The first stator coils 2 (?a, 2b) are respectively biased in opposite directions.

Next, during the rotation angle from 7 da to 9 ff', the Hall elements 24, 25, and 26 have logic values of 0.0.1 corresponding to the south pole, south pole, and north pole.

Therefore, the third stator coil 4 (4a, 4b) is directed in the forward direction.
The second stator coils 3 (3a, 3b) are each biased in opposite directions.

Since the same applies hereafter, the description will be omitted.

As described above, the energizing current is selectively supplied to each wire of the stator 1 to rotate the rotor 5 clockwise. Rotor 5
When rotating counterclockwise (counterclockwise rotation hereinafter referred to as counterclockwise rotation), the force is applied to each wire in the opposite manner to that described above.

However, the relationship between the center of magnetic flux generated in the stator coil and the center of polarity of the permanent magnet determines the direction of torque.

Therefore, depending on the center position of the magnetic flux generated for the stator coils and the polarity of the rotor's permanent magnets, a force is generated to the left or right depending on the position of one center, resulting in the resultant torque of the two stator coils. (Figure 6 (2))
As shown by the solid line, the composite tone is
, causing putt saturation. Therefore, the Hall element 24.2
5. If you shift the arrangement position of 26 and make the energizing timing of each fixed wire wheel earlier, the drop will be reduced as shown by the dotted line. However, even if it is used as a reverse rotation drive, there is still a put point in the torque, and b) there is a possibility that the torque becomes large as shown in the figure. As described above, the conventional technology has the drawback of generating torque ripple and causing fluctuations in the rotation angle, and this is a fatal drawback, especially in the direct drive system that drives precision recording devices, etc. . For example, used to drive floppy disks,
Uneven rotation causes reading/writing errors. Furthermore, as the storage capacity increases, errors become even larger.

[Purpose of the invention]

The present invention eliminates the above-mentioned drawbacks and provides a drive detection circuit for a brushless motor that eliminates uneven rotation of the brushless motor and maintains a constant rotational angular velocity by appropriately arranging a plurality of position detection Hall elements. .

[Structure and operation of the invention]

Identical structures (corresponding parts are indicated by the same reference numerals), and embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the first, second and third stator coils 2,
The relationship between 3.4 and the Hall elements arranged therein is shown. That is, five Hall elements 24, 27° 25, 26, 28 are provided at the center of each wire ring 2a, 2t), 3a, 4a, 4b, and the Hall elements 24, 26 are spaced apart by 12 fields, and the other Hall elements 27, 25° 28 are arranged at equal intervals of 6 (1') on the same circumference. In Figure 2, Hall elements 24, 25, 26, 2
28 and terminal 10 of the position detection function circuit 9a.
It is a connection diagram with ゜'11, 12, 13, 14.15.

The conductive wires extending in the vertical direction of the Hall elements 24, 25, 26, and 27.28 are common input conductors from the outside to each Hall element.

In this circuit, each Hall element has a rotation angle C of 15
'', positive and negative signals are generated as shown in the figure.For example, for the Hall elements 26 and 28, current flows through the dotted line circuit, causing a short circuit.Therefore, to prevent this, R1 and R2 Insert the resistor.

Further, regarding the Hall elements 27 and 28, a current flows through the chain line circuit, causing a short circuit. Therefore, to prevent this, R
1 resistor is required. Therefore, by inserting the resistors R1 and R2, the Hall elements 24, 2526, 27, and 28 are protected even if the polarity changes successively from N to S, and the resistors R1 and R2 play the role of preventing short circuits.

Next, to explain the operation, for example, under the same conditions as the conventional example of the prior art between the rotation angle I and 1, the Hall elements 24 and 27 correspond to the N pole and the Hall elements 25
corresponds to the south pole and is in the opposite direction, and Hall elements 26 and 28 correspond to the north pole and are in the forward direction.

Therefore, the terminal of the circuit including the Hall element 24 is 15 (
+) and 14←), and the terminals of the circuit containing the Hall element 26.28 are 13 (A) and 12 (→), and the terminals of the circuit containing the Hall element 25.27 are 10 (-1-) and 11.
(c) If we express this in logic, the first φ second ・
It becomes 1.0°0 corresponding to the third stator coil 2, 3.4.

Therefore, the control circuit (IC) 9 is activated by the logic circuit, the gate of the output side current switching element 9b is activated, and the input terminal 22
The first stator wire 62 (2a, 2b) is urged in the forward direction from the third stator wire ring 4 (4a).

4b') is urged in the opposite direction = - ゛　　　　7　Rotor 5 and stator The rotor 5 rotates clockwise due to the magnetic action between the rotor 5 and the rotor 1.

This is the same condition as the biasing of the first and third stator wire wheels 2 and 4 in the conventional example described above, where the rotation angle is 1 da or up to 31f. Therefore, when the rotation angle is from "to 15", the biasing of the first and second stator coils 2 and 3 in the prior art is different from the biasing of the first and third stator coils 2 and 4 in the present invention. energized and converted.

Similarly, convert it as follows.

Conventionally, the direction of torque was determined by the relationship between the center of magnetic flux generated by passing current through the wires of the stator and the center of the magnetic flux of the permanent magnets of the rotor. When flowing, the torque acts to the right at the position where it is, the torque acts to the left at the position where it overlaps, and the torque acts to the left at the position where it occurs.As a result, the resultant torque is to the right, then zero, then a smaller torque, and the torque is to the right. The rotor rotates clockwise.

Thus, torque ripple occurs. In this invention, the Hall element 24,
25.26, 27.28 to detect the position and commutate the first, second, and third stator coils 2, 3.4 as shown in the table above to rotate them constantly and smoothly without torque reduction. When rotating counterclockwise, by supplying the above-mentioned opposite bias to the first, second, and third stator wire wheels 2, 3.4, similarly, constant and smooth rotation is achieved without torque reduction. .

Although this invention has been described with the rotor 5 having 8 poles and the stator 1 having 6 poles, it should be noted that the present invention is applicable to a number of poles that is an integral number (n) times that of the above.

〔Effect of the invention〕

As explained above, the present invention consists of a rotor 5 made of a flat permanent magnet having eight magnetic poles, and a rotor 5 that is separated by an air gap 6 (
Six stator coils 2a, 2b wound at f' pitch,
3a@3b, 4a-4b, the stator 1 has first, second and third stator wire rings 2, 3.4, and the central part of each wire ring 2a, 2b, 3a, 4a, 4b. Five Hall elements 24, 25, 26, 27 detect the position of the rotor 5.
．． 28, with 12 [f spacing in one place, and 6" in the other places.
Formed at equal intervals. In this way, the configuration is such that the first, second, and third stator coils 2, 3.4 are selectively energized and rotated through the control circuit (IC) 9, so there is no torque ripple as in the prior art. That is, the problem of rotational unevenness caused by changes in rotational angular velocity has been solved, and smooth rotational driving has become possible. Therefore, it is most suitable for a direct drive system for driving precision recording devices, etc., and has the advantage of contributing to improved reliability as a drive source for accurately controlling other devices.

[Brief explanation of drawings]

FIG. 1 is a relationship diagram between each stator wire ring and each Hall element of the present invention, FIG. 2 is a connection diagram between each Hall element of the present invention and a terminal of a position detection function circuit, and FIG. a) and (
b) is a relationship diagram and a wiring diagram between each stator coil and each Hall element in the conventional example, Fig. 4 is a cross-sectional view of the brushless motor, and Fig. 5 is the inside of the control circuit (IC) in the conventional example. Schematic diagram, No. 6
Figures (a) and (b) are explanatory diagrams showing the relationship between torque and rotation angle in a conventional example.

Claims (2)

[Claims] (1) In a brushless motor equipped with a rotor equipped with an 8n-pole permanent magnet and a stator with a 6n stator coil at the base, only one location inside the stator coil is 120°.
Sequentially 60° x (1/n) based on x (1/n) intervals
It is equipped with five position detectors arranged at equal intervals to detect the position of the rotor, and a control circuit having a current switching control element that supplies energizing current to the stator coil. 1. A drive detection circuit for a brushless motor, characterized in that the energizing current is selectively supplied to a stator coil based on a position detection signal generated by a rotor, so that the rotational angular velocity of a rotor is kept constant and the rotor rotates. (2) The position detector is composed of a magnetically sensitive element, and short-circuit prevention resistors R1 and R2 are included in the circuit to protect the magnetically sensitive element.
A drive detection circuit for a brushless motor according to claim 1, further comprising a brushless motor drive detection circuit.