JPS62126889A - Controlling method for 3-phase brushless motor and rotor used for the same method - Google Patents

Abstract

PURPOSE:To readily obtain a 3-phase operation by one magnetoelectric transducer by employing as sections for detecting the positions of a rotor three types of N-pole, S-pole and mo magnetic flux. CONSTITUTION:Cutouts or nonmagnetized portions are formed at the peripheral edge of a rotor 15, and the poles of a rotor position to be detected by a magne toelectric transducer 31 are disposed at an equal interval in the sequence of N-pole, S-pole and zero. A two-output element is used as the element 31, and the two outputs of the element 31 are set to 3 stages of N, S and zero. An armature current is conducted by the high output level of this output and by a logic operation.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a brushless motor that is used for a 0AfiJ fan drive unit of a personal computer, etc., and that is electronically rectified by a switching circuit using a Hall IC. The present invention relates to a control method and its rotor shape.

[Prior Art] Today, brushless motors that perform commutation using Hall elements etc. do not generate electrical noise due to the commutator, and are extremely easy to maintain.
AJII! It has come to be widely used as a fan drive unit for appliances.

An example of such a small brushless motor is the 11th motor.
A flat motor lO as shown in FIG. 1 and FIG. 12 is mentioned. As shown in FIG. 11, the motor IO has a flat rotor yoke 16 fixed to a motor shaft 27, and the motor shaft 27 is rotatably provided in a motor case 28. As shown in FIG. 12, on the lower surface of the rotor yoke 16, four approximately triangular rotor magnets 17 are arranged at 90° intervals so that different magnetic poles are successively adjacent to each other, and these rotor yokes 1B and rotor magnets 17 forms a rotor 15.

Further, as shown in FIG. 11, a stator coil 13 is provided on the stator yoke 12 fixed to the motor case 29 so as to face the rotor magnet 17. In the three-phase brushless motor 10, as shown in FIG. 12, three stator coils 13 are generally provided at 120° intervals, and in order to detect the position of the rotor 15, three magnetoelectric transducers 31 are arranged at 60° intervals. They are set at intervals.

Note that this mechanical angle of 60° corresponds to an electrical angle of 120° in the motor IO with four pole magnetization.

In such a three-phase motor 10, the torque characteristic is as shown in FIG. 14. Since the motor IO is operated using a relatively high torque portion of each stator coil 13, the efficiency of the motor 10 is high, and the single-phase Because it does not have a torque dead center like a motor,
There are various advantages such as making it easier to start the motor IO.

[Problems to be Solved by the Invention] As mentioned above, although the three-phase brushless motor has excellent characteristics, it requires three magnetoelectric conversion elements and many logic gates to control the armature current flowing to the stator coil. This has the disadvantage of requiring a large amount of time, complicating the control circuit, and increasing manufacturing costs.
Even if the control circuit were simple, three magnetoelectric transducers were required as shown in FIG. 13, and three-phase motors were considered relatively high-end machines and had the disadvantage that they were not widely used.

The present invention overcomes these drawbacks and provides a control method that allows three-phase operation to be easily performed using a single magnetoelectric transducer, and also provides a rotor for easily carrying out the method.

[Means for Solving the Problems] The method for controlling a three-phase brushless motor according to the present invention solves the following problems by providing a notch or a non-magnetized portion on the circumference of the rotor
The magnetic poles of the rotor position detected by the magneto-electric conversion elements are arranged at equal intervals in the order of N pole, S pole, and Pole, and a two-output type element is used as the magneto-electric conversion element, and each of the two outputs of the magneto-electric conversion element is is divided into three stages by N, S, and zero magnetic poles, and the armature current is conducted at each high output level, and 'i1!' is also determined by logical operation. A method for controlling a three-phase brushless motor, characterized in that a machine current is applied to the motor, and
The rotor used in this method has an N pole, an S pole, and a notch or a non-magnetized part arranged in sequence on its outer periphery as a position detection magnet having a width that is 2/3 of the center angle of the rotor magnet. This rotor is characterized by the following features:

[Operation] The method according to the present invention uses a two-output type magnetoelectric transducer and sets the magnetic poles of the rotor detected by the magnetoelectric transducer to N, S, and zero.

The output of the magnetoelectric transducer is set to three levels: H (high) level, M (middle) level, and L (low) level, and by logical operation of each H level of both outputs and each H level, 120
° This is a control method for a three-phase brushless motor that can obtain out-of-phase currents, and the rotor is divided into N-pole, S-pole, and Since the chipped or non-magnetized parts are provided sequentially, the position detection part of the rotor can be easily set to N, S, and zero to 1' electrical angle.
This is a rotor that can obtain different outputs from magnetoelectric transducers every 20 degrees.

[Example] A three-phase brushless motor 10 according to the present invention uses a linear Hall IC 32 as a magnetoelectric conversion element 31, and
As an example of the rotor 15, as shown in FIG.
Six approximately triangular rotor magnets (17) are provided with different magnetic poles adjoining each other in order, and cutouts or non-magnetized portions 18 having a central angle of 40° centering on the magnetic pole boundary line 21 are provided at 120° intervals. form.

When the center of the stator coil 13 and one of the magnetic pole boundary lines 21 of the rotor magnet 17 match, magnetoelectric conversion is performed to a position corresponding to the center position of the rotor position detection portion 25 or notch 18 of the rotor magnet 17. Element 31 is arranged.

The Hall IC 32 serving as the magnetoelectric transducer 31 is of a linear type, and as shown in FIG. When detecting the position of the rotor 15 having a chipped or non-magnetized portion 18, the Bi electric conversion element 31
The detected magnetic flux becomes N, S, and zero in sequence, and the output of the magnetoelectric transducer 31 becomes H (high) level, M (medium) level, and L ( When a low) level output appears, and in the dual-output type Hall IC 32, when one output is H level, the other output is output as L level, and when the non-magnetized portion 18 is located at the magnetoelectric conversion element 31, , the two outputs of the magnetoelectric transducer 31 have the same M level.

Note that this change in output level changes every 400 mechanical angles, and since the rotor 15 is magnetized with six poles, it corresponds to 120'' electrical angles.

As shown in FIG. 2, the output of the magnetoelectric transducer 31 is converted into I by a comparator 37 between the M level and the H level.
! The armature current control element 3 uses only the H level as the I (L threshold) value Vo as the control current to the armature current control element 35.
5 is made conductive, and by using an AND circuit that uses these two control currents as negative inputs, the two outputs of the magnetoelectric transducer 3] are generated! ! ! (When the /i voltage is lower than 0 and the two armature current control elements 35 are non-conductive, the input of the AND circuit is set to H level, the output of the AND circuit is set to H level,
The output is used as a control current for the remaining one armature current control element 35 to conduct the remaining one armature current control element 35, and the three-phase control current having a phase difference of 1200 in electrical angle is connected to the comparator 37 and logic. This can be easily obtained by using a circuit, and as a result, the armature current can be controlled.

However, as shown in FIG. 5, the output of the magnetoelectric conversion element 31 is used as the base input of the transistor that is the armature current control element 35 via the voltage dividing resistor 38, without using the comparator 37, etc., and the threshold voltage Vo is The value of the voltage dividing resistor 39 is determined so that the transistor which is the armature current control element 35 is conductive, and thereby the two armature current control elements 35 are controlled to be conductive by the H level output of the magnetoelectric conversion element 3I. , said 2
Each collector of one armature current control element 35 is connected to one in parallel with three stator coils 13 via a diode in the opposite direction.
In some embodiments, the armature current control element 35 is connected to one resistor, and the resistor is connected to the base of a transistor, which is the remaining armature current control element 35, through a forward diode.

In this circuit, the two outputs of the magnetoelectric transducer 31 generate 2
directly actuates the armature current control elements 35, iItm
When either of the two armature current control elements 35 conducts due to a voltage drop in the stator coil 13 due to conduction of the child current, the voltage applied to the diode becomes forward biased, and a current flows through the resistor in parallel with the stator coil 13. The remaining one armature current control element 35 is made non-conductive, and the current is directly operated by the magnetoelectric conversion element 31.
When both armature current control elements 35 are non-conductive,
The remaining resistor 71 is used to supply current to the base '1 of the current control element 35 so that a slight voltage drop occurs in the resistor in parallel with the stator coil 13.

Therefore, in this actual circuit, the voltage dividing resistor 39 that determines the base bias of the magnetoelectric conversion element 31 is replaced with the comparator 37, and a NOR circuit that performs NOR using one resistor and three diodes in parallel with the stator coil 13 is used. Therefore, the number of elements constituting the control circuit is extremely small, making maintenance easy and making it possible to manufacture the three-phase motor IO at low cost.

That is, when performing a logical operation on the two outputs V^ and VB of the magnetoelectric conversion element 31, it is not limited to an AND circuit with a negative input as described above, but also an N circuit such as a negative OR.

There may be eight circuits.

In short, both of the two outputs VA and V of the magnetoelectric conversion element 31 are H.
Any logic circuit that can output a high output when the level is low is sufficient.

The control method for the three-phase brushless motor 10 according to the present invention is a method in which the rotor 15 sequentially applies N, S, and zero cross-linked magnetic fluxes to the magnetoelectric transducer 31 having linear output characteristics as described above. The rotor 15 used in this method is not limited to the six types of magnetization as described above, but can be a multi-pole machine of various types such as four types of magnetization, eight types of magnetization, etc.

That is, in a four-pole magnetic rotor 15 having four rotor magnets 17, four approximately right triangular rotor magnets 17 are sequentially arranged adjacent to each other at 90° intervals so as to have different polarities, as shown in FIG. The rotor magnet (1? 2 of the central angle of
In some cases, a notch with a central angle of 60° corresponding to 60° is provided, or as shown in FIG. When the magnet 25 for use is provided as N pole, S pole, and non-magnetized portion 18 in sequence at 60° intervals, further,
In the 8-pole magnetic type, as shown in FIG. 8, approximately triangular rotor magnets 17 are arranged at 45° intervals, and the rotor position detection magnets 25 provided on the outer periphery have N poles, N poles, and N poles at 30° intervals.
There are cases where the S pole and rIB1-free portion 18 are used.

The angle of this rotor magnet) 17 is an angle expressed as 380'/N if the number of magnetic poles is N, and the angle of the rotor position detection magnet 25 is 120' electrical angle converted into mechanical angle. It is expressed as 120X2/N.

In addition, when the non-magnetized portions 18 are provided at every other magnetic pole boundary line 21 with the magnetic pole boundary line 21 as the center, the polarity of the rotor position detection magnet 25 and the rotor in contact with the rotor position detection magnet 25 are determined. The polarity of the magnet 17 matches, and the rotor position detection magnet 25 is used as in the 6-type magnetized type rotor 15 shown in FIG. 1 of the first embodiment and the 4-type magnetized type rotor 15 shown in FIG. Instead of providing a separate part, simply provide a notch to replace the non-magnetized part 1B,
The rotor position detecting magnet 25 portion can be formed, and the manufacture of the rotor 15 becomes extremely easy. Of course.

The rotor position detection magnet 25 is connected to the rotor magnet 1.
7, as shown in FIG. 9, the center of the non-magnetized portion 18 and the magnetic pole boundary! 121, it is not necessary to arrange the magnetic poles in the order of N pole, S pole, and zero, and
A rotor position detection magnet 25 whose center angle width of N, S, and zero magnetic poles is 273 of the center angle of rotor magnet) 17.
It suffices if the magnet is provided around the rotor 15, and furthermore, it is not limited to the case where it is provided around the rotor 15, but may be provided coaxially with the rotor magnet 17 as shown in FIG. 1θ.

Furthermore, the stator coils 13 are not necessarily installed at 120° intervals; in the case of the 4-type magnetized rotor 15,
As shown in the figure, they are generally arranged at intervals of 120°, but they are arranged at an electrical angle of 240°, which is the same as the electrical angle of the mounting position of the stator coil 13 in the 4-type magnetization type. When using the 6th class magnetized rotor 15, the stator coils 13 are spaced at 80° intervals as shown in FIG. 1, and when the 8th class magnetized rotor 15 is used, the stator coils 13 are spaced at 60° intervals. By arranging the stator coils 13, the stator coils 13 can be gathered on one side of the stator yoke 12 while ensuring good rotational torque characteristics.
By assembling a control element in 2k, the motor 10 can be made smaller.

[Effect of the invention 1] The method for controlling a three-phase brushless motor according to the present invention has three magnetic pole parts for detecting the rotor position: N pole, S pole, and no magnetic flux.
By using 1 (11 magnetoelectric conversion elements), two outputs that change every 120 degrees of electrical angle can be obtained, and furthermore,
Using one AND gate that takes the AND of these two outputs,
Or by using a NOR gate that is a negative logical sum, etc.
To manufacture a three-phase brushless motor that is easy to maintain and inexpensive by reducing the number of control elements, mainly Iji electric conversion elements, because it can easily control three-phase currents having a phase shift of 120 degrees. This is a control method for a brushless motor that allows the magnetic poles of the first position detection part to be of three types: N pole, S pole, and no magnetic flux, thereby easily obtaining the output of a magnetoelectric transducer that sequentially changes every 120 degrees. This is a three-phase brushless motor rotor that can.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the rotor shape and stator coil arrangement according to the present invention, and FIG. 2 is a circuit diagram of the present invention.
Figures 3 and 4 are diagrams showing the output of the magnetoelectric conversion element, Figure 5
The figure is a circuit diagram of another embodiment, and FIGS. 6 to 10 are diagrams showing rotor shapes in other embodiments.
The figure is a cross-sectional view of a typical flat brushless motor, Figure 12 is a diagram showing the rotor shape, etc. of a typical brushless motor, Figure 13 is a simple circuit diagram of a typical three-phase brushless motor, and Figure 14 is a diagram showing the rotor shape of a typical brushless motor. FIG. 3 is a diagram showing torque characteristics of a three-phase motor. 10=motor, 12=stator yoke, 13=
Stator coil, 15=rotor, 16=rotor yoke, 17=rotor magnet, 18=non-magnetized part,
21=magnetic pole boundary line, 25=rotor position detection magnet, 27=motor shaft, 28=motor case, 31
= magnetoelectric conversion element, 32 = Hall IC135 = armature current control element. 37=Comparator, 39; Voltage dividing resistor. 4i・) Self 7"-q14+WFig. 3 'Jp 4 r f 8 Fig. 9 Fig. 10 Fig.

Claims (3)

[Claims] (1) By providing a notch or a non-magnetized portion on the periphery of the rotor, the magnetic poles at the rotor position detected by one magnetoelectric conversion element are arranged at equal intervals in the order of N pole, S pole, and zero, and the magnetoelectric conversion element In addition to using a two-output type element, each of the two outputs of the magnetoelectric conversion element is divided into three stages with magnetic poles of N, S, and zero, and the armature current is conducted at each high output level, and the armature is also controlled by logic operations. A method for controlling a three-phase brushless motor characterized by conducting current. (2) On the outer periphery of the rotor, an N pole, an S pole, and a notch or non-magnetized part are sequentially arranged as a position detection magnet with a width that has a center angle that is 2/3 of the center angle of the rotor magnet. Characteristic rotor for three-phase brushless motors. (3) A feature in that cutouts or non-magnetized parts having a width that is 2/3 of the central angle of the rotor magnet are provided at every other magnetic pole boundary line, with the magnetic pole boundary line as the center line. A rotor for a three-phase brushless motor according to claim 2.