JP2000316266A - Variable reluctance position detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the pole positions of a motor and obtain high detecting resolution for position control and speed control. SOLUTION: This variable reluctance position detector is provided with a first position detecting part 10 and a second position detecting part 20. The first position detecting part 10 is constituted of a first rotor part 13, whose radius is periodically changed P times per one rotation as a function of mechanical angle, and a first stator 11 which is arranged facing the rotor part 13 and has stator magnetic poles, around which windings are wound. The second position detecting part 20 is constituted of a second rotor part 23, whose radius is periodically changed Z times per one rotation as a function of mechanical angle, and a second stator which is arranged facing the rotor part 23 and has stator magnetic poles 21 around which windings are wound. The first and second position detecting parts 10, 20 are so arranged that a rotating shaft 4 is commonly used, and the stator magnetic poles of the first stator 11 and the stator magnetic poles of the second stator 21 do not overlap in the shaft direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable reluctance type position detector used for detecting an angle of a motor shaft of a permanent magnet type motor.

[0002]

2. Description of the Related Art FIG. 25 shows a conventional example of a variable magnetoresistive resolver which is one of such variable magnetoresistive position detectors. The rotor core 3 of this resolver has its center O ′ eccentric with respect to the center O of the motor rotation shaft 4 by δ. Therefore, the radius of the rotor core 3 starting from the center O of the motor rotation shaft 4 changes periodically once per rotation as a function of the mechanical angle.

[0003] The stator 1 has four magnetic poles P1 to P4 arranged equally, and the windings W10 to W40 are wound around the magnetic poles P1 to P4, respectively.
The detection windings W1 to W4 are wound respectively. FIG.
As shown in FIG. 6, the excitation windings W10 to W40 are connected to the AC excitation power supply 5 (the output e
Are connected in series between one end and the other end of e = Em · sin ωt), and the detection windings W1 and W3 and the detection windings W2 and W4 are also connected in series as shown.

The detection windings W1, W3 and W2,
W4 outputs the following signal voltages Va and Vb amplitude-modulated to a sine wave or a cosine wave according to the rotation angle θ of the rotor core 3, respectively. Va = K · Em · sin ωt · cos θ Vb = K · Em · sin ωt · sin θ where Em and K are constants

Next, a principle for converting the output signal voltages Va and Vb into a rotation angle θ will be described with reference to FIG. In principle, Vb / Va = sin θ / cos θ = t
is anθ, the rotation angle θ is obtained by calculating the arc tangent of (Vb / Va).

However, in practice, the instantaneous values of the signal voltages Va and Vb are not used for calculation. That is, the signal voltages Va ′ = K ′ · cos θ, V obtained by synchronously detecting the signal voltages Va and Vb in the synchronous detection unit 50 and removing the excitation frequency component.
b ′ = K ′ · sin θ, and these signal voltages V
a ′ and Vb ′ are input to an arithmetic unit 52 via an A / D converter 51. Then, the calculation unit 52 executes a calculation for obtaining an arc tangent of (Va ′ / Vb ′) to obtain the electrical angle θe.
Get. The actual rotation angle θm of the rotor core 3 is obtained by dividing the electrical angle θe by the multiple of the axis. Since the shaft double angle of the conventional example shown in FIG. 25 is 1X, θm =
θe. FIG. 28 shows the relationship between the actual angle θm and the electrical angle θe.

[0007]

The variable magnetoresistive resolver having a shaft multiplication angle of 1X is provided with an actual rotation angle θm of the motor shaft 4.
And the detection angle θe correspond one-to-one, so that both detection of the rotor magnetic pole position for driving the permanent magnet type motor and detection of the angle of the motor shaft 4 for performing positioning control and the like are possible. There is an advantage.

However, on the other hand, the resolver is not affected by the harmonic components of the output and the detection angle θ with respect to the rotation angle θm.
A problem arises due to a small change amount of e.
That is, it is difficult to perform high-resolution angle detection for positioning control. Further, when obtaining the rotation speed, the amount of change in the position (angle) per unit time is calculated, so that it is difficult to obtain a high-precision speed, and complicated calculation means is required.

A method is also conceivable in which two types of resolvers having different double angles are used, one resolver detects the magnetic pole position of the motor rotor, and the other resolver performs high-resolution angle detection. The method has the following problems. That is, in order to manufacture the above two types of resolvers, usually, dedicated stator dies and rotor dies are required respectively. Therefore, the above method has a high implementation cost.

In the case where the two types of resolvers are arranged to overlap each other in the axial direction, the overall length of the position detecting section becomes long,
In the case of concentric configuration, problems such as a complicated structure arise. Further, the conventional resolver has the following problems. That is, when combined with a three-phase motor, in order to generate an excitation switching signal for the motor, three-phase motor data is output from the memory based on the detected angle θe data.
It is necessary to derive the phase current command value. This complicates the configuration of the excitation switching circuit or the current command circuit.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is possible to detect a magnetic pole position of a motor to be applied and to obtain a variable detection capable of obtaining a high detection resolution for position control and speed control. It is an object to provide a magnetoresistive position detector.

[0012]

According to a first aspect of the present invention, there is provided a first rotor portion having a radius which changes periodically P times per rotation as a function of a mechanical angle; A first position detector comprising a first stator having 4a stator poles each having a wound winding; and a Z-period whose radius is Z times per revolution as a function of mechanical angle. And a second stator having 4a stator magnetic poles disposed opposite to the rotor and having windings wound therearound. A position detector, wherein the first and second position detectors share a rotation axis, and a stator magnetic pole of the first stator and a stator magnetic pole of the second stator. Are arranged so as not to overlap each other in the axial direction, and the numerical values P, a and Z are set as follows. That. P: an integer of 1 or more a: an integer that satisfies a = 1 when P = 1, and satisfies a ≦ P / 2 when P ≠ 1 Z: satisfies the following equation Z = (4n ± 1) P, where n is an integer of 1 or more. In the second invention, in the first invention, the 4a stator magnetic poles provided on the first and second stators are arranged in a circumferential direction. The first and second stators are identical to each other and radially protrude inward from 4a positions among the positions obtained by dividing the annular stator yoke portion into N at equal angular pitches. In order to prevent overlapping of the magnetic poles, one of them is rotated by θp with respect to the other and arranged so that the numerical values N and
The angle θp is set as follows. N: When P = 1, N = 4 × 2 = 8 When P ≠ 1, N = 4P θp: When P = 1, θp = (360/8) degrees When P ≠ 1, θp = (360 / P) degrees According to a third aspect of the present invention, the variable magnetoresistive position detector according to the first aspect of the present invention is provided in a permanent magnet type motor having a pole pair P having a permanent magnet in a rotor, and a detection signal of the first position detecting section is provided. It is used to detect the rotor magnetic pole position of the motor. In a fourth aspect, the radius is 1 as a function of mechanical angle.
A first rotor portion which periodically changes P times per rotation, and a first stator having 6a stator magnetic poles disposed opposite to the rotor portion and each having a wound winding. A first position detector configured, a second rotor section whose radius varies Z times per revolution as a function of mechanical angle, and a second rotor section disposed opposite to the rotor section, each having a winding. And a second stator having 6a stator magnetic poles wound with a second stator, and the first and second position detectors share a rotation axis. And the stator magnetic poles of the first and second stators are arranged so as not to overlap each other in the axial direction, and the numerical values P, a and Z are set as follows: You have set. P: an integer of 1 or more a: an integer satisfying a = 1 when P = 1, and an integer satisfying a ≦ P / 2 when P ≠ 1 Z: satisfying the following expression Z = (6n ± 1) P where n is an integer of 1 or more. In a fifth aspect based on the fourth aspect, the 6a stator magnetic poles provided in the first and second stators are arranged in a circumferential direction. The first and second stators are identical to each other and radially protrude inward from 6a positions among the positions obtained by dividing an annular stator yoke portion into N at equal angular pitches. In order to prevent overlapping of the magnetic poles, one of them is rotated by θp with respect to the other and arranged so that the numerical values N and
The angle θp is set as follows. N: When P = 1, N = 6 × 2 = 12 When P ≠ 1, N = 6P θp: When P = 1, θp = (360/12) degrees When P ≠ 1, θp = (360 / P) degrees According to a sixth aspect of the present invention, a variable magnetoresistive position detector according to the fourth aspect of the present invention is provided in a three-phase permanent magnet type motor having a pole pair P having a permanent magnet in a rotor, and a detection signal of the first position detector is provided. Is used to detect the rotor magnetic pole position of the motor. In a seventh aspect based on the first or fourth aspect, at least a tooth pitch corresponding to the Z teeth of the second rotor portion is fixed to an inner peripheral surface of a stator magnetic pole of the second stator. Child teeth are formed. In an eighth aspect based on the first or fourth aspect, the first and second stators have a configuration in which a stator yoke portion is integrated or shared.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the variable magnetic resistance type position detecting section of the present invention will be described below in detail with reference to the drawings.

(First Embodiment) FIG. 1 is a longitudinal sectional view showing a first embodiment of a variable magnetoresistive position detector according to the present invention having a function as a resolver. FIG. 2 and FIG.
FIG. 2 is a sectional view taken along line AA ′ and line BB ′ of FIG. 1.
In this embodiment, the rotor 30 has the rotor core 13 as the first rotor portion and the rotor core 23 as the second rotor portion arranged in the axial direction so as to share the rotation shaft 4. Have a configuration. The rotor core 13 has substantially two teeth 13a (two projections along the major axis) because the plane is an elliptical plane, so that the radius is equal to the mechanical angle during one rotation. It changes periodically twice as a function. That is,
Assuming that the number of periodic changes of the radius in one rotation is P (an integer of 1 or more), P = 2 in the rotor core 13.

The stator 11 includes an annular stator yoke 7
4 protruding radially inward of the yoke 7
Stator poles P1, P3, P4, and P6, and detection windings W1, W3, W4 wound around the respective stator poles.
W6. The stator 11 includes the rotor core 1
3 are disposed opposite each other with an air gap therebetween, and the rotor core 1
3 together with the first position detecting unit 10 having a shaft double angle of 2X. The above-described stator magnetic poles and detection windings provided on the stator 11 constitute a stator magnetic pole section 12 shown in FIG.

The rotor core 23 has 50 teeth 2 on its outer peripheral surface.
3a is formed. Thus, during one revolution, the radius will periodically change 50 times as a function of mechanical angle. That is, assuming that the number of periodic changes in the radius in one rotation of the rotor core 23 having the teeth 23a on the outer peripheral surface is Z, the number Z is 50. The number of times Z, that is, the number of the teeth 23a is set so as to satisfy the following relationship. Z = (4n ± 1) P (1) where n is an integer of 1 or more In the above example, since P = 2, n is set to n = 6 and Z
= (4 × 6 + 1) × 2 = 50.

On the other hand, the stator 21 includes an annular stator yoke portion 8, four stator magnetic poles P2, P5, P7, and P8 radially protruding toward the inside of the yoke portion 8. Detection windings W2, W5 respectively wound around the child magnetic poles
W7 and W8. The stator 21 is disposed around the rotor core 23 so as to be opposed to the rotor core 23 with an air gap therebetween.
0. The above-described stator magnetic poles and detection windings provided on the stator 21 correspond to the stator magnetic pole portions 2 shown in FIG.
2. The stators 11 and 21 are arranged in the axial direction such that the respective yoke portions 7 and 8 are integrally joined.

The stator magnetic poles P1 to P8 are located on a line dividing the stators 11 and 12 at an equal angular pitch. Now, assuming that the number of equal angle divisions is N, the number of divisions N is set so as to satisfy the following relationship. When P = 1, N = 4 × 2 = 8 (2) When P ≠ 1, N = 4P (3) In the above example, since P = 2, equation (3) Is set to N = 8 based on the relationship. That is, the angle formed by the equally divided lines is set to 45 degrees.

On the other hand, the number of stator magnetic poles formed in the stator magnetic pole portions 12 and 22 is 4 out of the above division number N, respectively.
It is set to a. Here, a is a numerical value given by the following relationship. A = 1 when P = 1 (4) a ≦ P / 2 when P ≠ 1 (5) In the above example, since P = 2, the relation of equation (5) is satisfied. Is determined based on the following equation, and as a result, the stator magnetic pole part 1
The number of stator poles formed in each of Nos. 2 and 22 is four.

The arrangement of the magnetic poles in the circumferential direction in the stators 11 and 21 is the same as shown in FIGS.
The magnetic poles P1, P3, P4, and P6 of the stator 11 and the magnetic poles P2, P5, P7, and P8 of the stator 21 make the stators 11, 21 relatively 360/2 = It is in a positional relationship rotated by 180 degrees.

Now, let the relative rotation angles of the stators 11 and 21 be θ.
When p is set, the rotation angle θp is set so as to satisfy the following relationship. When P = 1, θp = 360/8 degrees (6) When P ≠ 1, θp = 360 / P degrees (7) In the above example, since P = 2, equation (7) , The relative rotation angle is set to θp = 180 degrees. In short, a total of eight stator magnetic poles P1 to P8 formed on the stator magnetic pole portions 12 and 22 are arranged in order in the circumferential direction at equal pitches, and are arranged so as not to overlap each other in the axial direction. I have.

Three small teeth 6 corresponding to the teeth 23a of the rotor core 23 are formed on the inner peripheral surface of each of the stator magnetic poles P1 to P8. Magnetic poles P1, P of stator 11
Although it is not necessary to form the small teeth 6 in 3, P4 and P6, in this embodiment, since the stators 11 and 21 are configured using the same stator iron plate, the magnetic pole P1 of the stator 11 is not used. , P
Small teeth 6 are also formed at 3, P4 and P6.

When the stator 11 is formed of a stator iron plate having no small teeth 6, the stator iron plate for the stator 11 and the stator 2
Although it is necessary to manufacture one stator iron plate, these iron plates can be manufactured using the same stator iron plate manufacturing mold. That is, if the iron plate manufacturing method of switching the punch of the punching stage of the inner diameter portion of the stator of the die for manufacturing the stator iron plate is adopted, the two types of stator iron plates can be manufactured by this die.

The detection windings W1 to W8 are connected as shown in FIG. That is, the windings W1, W3
The windings W4 and W6, the windings W5 and W7, and the windings W8 and W2 are connected in series, respectively, and these are connected in parallel between terminals T1 and T2. Terminal T1, T2
Between the AC excitation power supplies 5A and 5B (output e is e = Em.
sin ωt) are connected in series. The terminal T3 to which these AC excitation power supplies 5A and 5B are commonly connected is grounded. In this embodiment, the detection winding W1
Or W8 also has a function as an exciting winding,
As in the case of the conventional example, it is of course possible to wind both the excitation winding and the detection winding around one stator pole.

The magnetic poles P1, P3, P4, P6 of the stator 11
The positional relationship between the rotor core 13 and the tooth portions (projections) 13a is determined by the tooth pitch of the rotor core 13 (one change in the rotor radius).
On the basis of (period), it is as follows. That is,
As shown in FIG. 2, since the magnetic pole P1 is directly opposed to the teeth 13a of the rotor core 13, the shift pitch is zero. In the magnetic pole P3, the shift pitch is (2 /
4), the deviation pitch of the magnetic pole P4 is (3/4), and the magnetic pole P6
In this case, the shift pitch becomes (1/4).

On the other hand, the teeth 23 of the rotor core 23 shown in FIG.
The number a is set so as to satisfy the relationship of the above equation (1). Therefore, the positional relationship between the small teeth 6 formed on the stator magnetic poles P2, P5, P7 and P8 and the rotor teeth 23a is based on the tooth pitch of the rotor teeth 23a.
It looks like this: That is, the shift pitch is zero at the magnetic pole P5, the shift pitch is (２) at the magnetic pole P7, and the magnetic pole P
8, the shift pitch is (3/4), and the shift pitch is (1/2) at the magnetic pole P2.

Based on the positional relationship between the magnetic poles of the stators 11 and 12 and the teeth of the rotors 13 and 23, the self-inductances L1 to L8 of the detection windings W1 to W8 are expressed as follows. L1 = La · cos (2θm) + Lda (8) L3 = La · cos (2θm + π) + Lda (9) L4 = La · cos (2θm + π / 2) + Lda (10) L6 = La Cos (2θm−π / 2) + Lda (11) L5 = Lb · cos (50θm) + Ldb (12) L7 = Lb · cos (50θm + π) + Ldb (13) L8 = Lb · cos (50θm + π / 2) + Ldb (14) L2 = Lb · cos (50θm−π / 2) + Ldb (15) where La, Lb, Lda, Ldb: constant θm: reference of rotor 30 Rotation angle from position (mechanical angle)

FIG. 5 shows the self inductances L1, L
3, the state of change of L4 and L6 is shown. The self-inductances L5, L7, L8, and L2 also change in a similar manner.
, L3 to L7, L4 to L8, L6 to L2, La
To Lb, Lda to Ldb, and 180 ° to 7.2 °.

The output signal voltages V1, V2 appearing at the output terminals T4, T5 and the output signal voltages V3, V4 appearing at the output terminals T6, T7 in FIG. 4 are as follows based on the above equations (8) to (15). Is represented by V1 = Ka · sinωt · cos (2θm) (16) V2 = Ka · sinωt · sin (2θm) (17) V3 = Kb · sinωt · cos (50θm) (18) V4 = Kb · sin ωt · sin (50θm) (19) where Ka and Kb are constants

As is apparent from the above equations (16) to (19), the variable magnetoresistive position detector according to the first embodiment has a function as a variable magnetoresistive resolver. The output signal voltages V1, V2 and V3, V4 are processed by the signal processing means shown in FIG. That is, the signal voltages V1, V2 and V3, V4 are synchronously detected by the synchronous detection section 60, respectively, and the signal voltages V1 ′ = Ka ′ · cos (2θm), V2 ′ = Ka ′ from which the excitation frequency components have been removed.
Sin (2θm) and V3 ′ = Kb ′ · cos (5
0θm), V4 ′ = Kb ′ · sin (50θm), and input these to the arithmetic unit 62 via the A / D converter 61.

In the operation unit 62, (V1 '/ V
2 ′) and (V3 ′ / V4 ′) are calculated to obtain the arc tangents, thereby obtaining the electrical angles θa and θb. Then, as shown in the following equation (20), the electrical angles θa and θb
By dividing by (P = 2) and 50 (Z = 50), the mechanical angle θm can be obtained. θm = θa / 2 (20) θm = θb / 50 (21) FIG. 7A shows the relationship between the electrical angle θa and the mechanical angle θm.
FIG. 7B shows the relationship between the electrical angle θb and the mechanical angle θm.

Here, the variable magnetic resistance type position detecting portion of this embodiment, which functions as a resolver, is used by assembling it with a permanent magnet type motor having a number of pole pairs P = 2 (number of poles 4) having a permanent magnet in the rotor. A description will be given of the case in which this is done. In this case, the signal voltages V1 'and V2' obtained by synchronously detecting the output signal voltages V1 and V2 of the position detection unit 10 have a phase difference 90 whose cycle matches the change cycle of the surface magnetic flux of the motor rotor. This is a two-phase signal. Therefore, when the motor is a two-phase motor, the signal voltages V1 'and V2' can be used as current command signals for each phase.
As a result, the configuration of the motor drive circuit can be simplified. In addition, since the signal voltages V1 'and V2' can be used to detect the rotor magnetic pole position of the motor, when the motor is a three-phase motor, the signal voltages V1 'and V2' are based on the value of the electric angle θa. A three-phase current command value is read from a memory (not shown), and excitation switching is performed based on the current command value.

On the other hand, the output signal voltage V of the position detector 20
3, electrical angle θb detected from V4 and actual rotation angle θ
Since m has the relationship of the above equation (21), for example, the electrical angle θ
Assuming that the detection resolution of b is 1 °, the detection resolution of the actual rotation angle θm is 1/50 = 0.02 °. That is, angle detection with extremely high resolution becomes possible. Furthermore,
The signal voltages V3 'and V4' obtained by synchronously detecting the output signal voltages V3 and V4 are sine wave signals whose phases are shifted from each other by an electrical angle of 90 degrees in 50 cycles per motor rotation. Therefore, this embodiment can also be used as a magnetic encoder or FG (frequency generator).

(Second Embodiment) FIGS. 8 to 10 show a second embodiment of a magnetoresistive position detector according to the present invention having a function as a resolver. In the second embodiment, as shown in FIG. 8, the rotor core 13 constituting the first position detecting unit 10 (see FIG. 1) has four teeth 13b, and is shown in FIG. As described above, the rotor core 23 constituting the second position detection unit 20 has 100 teeth 23b. Then, the stator 11 of the first position detecting section has a total of 8
Stator poles P1, P3, P6, P8, P9, P1
1, P14 and P16, and the same number of stator magnetic poles P2, P4, P5, P
7, P10, P12, P13 and P15.

Excitation windings W10 to W160 are wound around the magnetic poles P1 to P16, respectively.
The detection windings W1 to W16 are wound, respectively, and are connected in the manner shown in FIG. That is, the excitation windings W10 to W160 are connected in series between one end and the other end of the AC excitation power supply 5 (the output e is e = Em · sinωt) in such a manner that the polarity is alternately inverted. Also, the detection winding W
1, W3, W9 and W11, detection windings W6, W
8, W14 and W16, detection windings W5, W7, W
13 and W15, and the detection windings W2, W4, W10, and W12 are also connected in series in such a manner that the polarity is alternately inverted. In this embodiment, both the independent excitation winding and the detection winding are wound around the magnetic poles of the stators 11 and 12, however, as shown in FIGS. 2 and 3, the excitation windings are wound around these magnetic poles. It is also possible to wind a winding that doubles as a wire and a detection winding.

As is clear from the above, in the second embodiment, the number P of the teeth 13b of the rotor core 13 (the number
(The number of periodic changes per rotation of radius 3) is P = 4
The numerical value Z (the number of periodic changes in the radius of the iron core 23) given by the above equation (1) is Z = (4 × 6 + 1) × 4 = 100
Where the numerical value N given by the above equation (4) is N = 4 × 4 = 1.
6, the value a given by the above equation (5) is a = 2, and the value θp given by the above equation (7) is θp = 360/4 =
Each is set to 90 degrees.

The first and second position detectors 10 and 20 have a double angle of 4X and 100X, respectively.
It is. Therefore, the relationship between the electrical angles θa and θb detected by the position detection units 10 and 20 and the corresponding mechanical angles θm is given by the following equations (22) and (21) corresponding to the above equations (20) and (21).
It is shown as (23). θm = θa / 4 (22) θm = θb / 100 (23)

(Third Embodiment) FIGS. 11 and 12 show a third embodiment of a magnetoresistive position detector according to the present invention having a function as a resolver. In the third embodiment,
The numerical value P is P = 5, and the numerical value Z is Z = (4 × 2 + 1) ×
5 = 45, numerical value N = 4 × 5 = 20, numerical value a = a
= 2, and the numerical value θp is set to θp = 360/5 = 72 degrees.

That is, as shown in FIG. 11, the rotor core 13 constituting the first position detecting section 10 has five teeth 1
As shown in FIG. 12, the rotor core 23 constituting the second position detection unit 20 has 45 teeth 23c.
have. Then, a numerical value N (= 20) is assigned to the stator 11.
4a (= 8) fewer magnetic poles P1, P3, P
5, P7, P9, P11, P13 and P15P, and the same number of magnetic poles P2, P4, P6, P
8, P10, P12 and P14 are formed. In addition,
Each of the magnetic poles P1 to P15 is wound with a pair of an excitation winding and a detection winding or a detection winding serving also as an excitation winding.
This winding is omitted in FIGS.

In the third embodiment, the relationship between the electrical angles θa and θb detected by the position detectors 10 and 20 and the corresponding mechanical angle θm is expressed by the following equations (24) and (25). become. θm = θa / 5 (24) θm = θb / 45 (25)

(Fourth Embodiment) FIGS. 13 and 14 show a fourth embodiment of a magnetoresistive position detector according to the present invention having a function as a synchro. In these figures, the rotor core 13 has substantially two teeth (two projections along the major axis) because the plane is an elliptical shape, and therefore, the radius increases during one rotation. It changes periodically only twice. That is, the number of periodic changes P of the rotor core 13 in one rotation is P = 2.

On the other hand, the rotor core 23 sharing the rotation shaft 4 with the rotor core 13 has 50 teeth 23a on its peripheral surface.
Is formed. Thus, during one revolution, the radius will periodically change 50 times as a function of mechanical angle. That is, the number Z of periodic changes of the radius in one rotation of the rotor core 23 is Z = 50. Note that the numerical value Z is set so as to satisfy the relationship of the following equation according to the above equation (1). Z = (6n ± 1) P (1) ′ where n is an integer of 1 or more. In the above example, P = 2.
= (6 × 4 + 1) × 2 = 50.

The stator magnetic pole part 12 of the stator 11 is shown in FIG.
As shown in the figure, six stator magnetic poles P1, P4, P5, P8, protruding radially inward from the stator yoke portion 7.
P9 and P12, and detection windings W1, W4, W5, W8, W9 and W1 respectively wound on the respective stator magnetic poles.
And 2. The stator 11 is disposed around the rotor core 13 with a gap therebetween, and forms a first position detecting unit 10 (see FIG. 1) having a double shaft angle 2X together with the rotor core 13.

Similarly, the stator magnetic pole portion 22 of the stator 21
As shown in FIG. 14, the six stator magnetic poles P2, P3, P6, which protrude radially inward from the stator yoke portion 8,
P7, P10, and P11 and detection windings W2, W3, W6, W7, W10 wound around the respective stator magnetic poles, respectively.
And W11. This stator 21
The rotor core 23 is opposed to the rotor core 23 with an air gap therebetween, and together with the rotor core 23, constitutes a second position detector 20 (see FIG. 1) with a shaft double angle of 50X. The above stator 1
The reference numerals 1 and 21 are arranged in the axial direction such that the respective yoke portions 7 and 8 are integrally joined.

The stator magnetic poles P1 to P12 are located on a line that divides the stators 11 and 12 at equal angles.
Is set so as to satisfy the relationship of the following expression according to the expressions (2) and (3). N = 6 × 2 = 12 when P = 1 (2) ′ N = 6P when P ≠ 1 (3) ′ In the above example, since P = 2, 3) N = 12 is set based on the equation. That is, the angle formed by each equally divided line is set to 30 degrees.

On the other hand, the number of stator magnetic poles formed on the stators 11 and 12 is set to 6a. Here, a is a numerical value given by the above equations (4) and (5). In the above example, since P = 2, a = 1 is determined. As a result, the number of stator magnetic poles formed on the stators 11 and 21 becomes six as described above.

The arrangement of the magnetic poles in the circumferential direction in the stators 11 and 21 is the same as shown in FIGS. Then, the magnetic poles P1, P4, P
5, P8, P9 and P12 and the magnetic poles P2, P3, P6, P7, P10 and P11 of the stator 21
Each of the stators 11 and 21 is relatively 3
60/2 = 180 degrees.

Now, let the relative rotation angles of the stators 11 and 21 be θ
Assuming that p, the rotation angle θp is set so as to satisfy the relationship of the following equation according to the equations (6) and (7). Θp = 360/12 degrees when P = 1 (6) ′ θp = 360 / P degrees when P ≠ 1 (7) ′ In the above example, since P = 2, (7) ) ′, The relative rotation angle is set to θp = 180 degrees.

In short, a total of twelve stator magnetic poles P1 to P12 formed on the stators 11 and 21 are sequentially arranged at equal pitches in the circumferential direction, and are arranged so as not to overlap each other in the axial direction. ing. Each of the above stator poles P1
Or the teeth 23a of the rotor core 23 on the inner peripheral surface of P12.
Are formed three each. The magnetic poles P1, P4, P5, P8, P9 on the stator 11 side
And P12 need not be provided with the small teeth 6.

Each of the above-mentioned detection windings W1 through W12 is
They are connected as shown in FIG. That is, the windings W1,
W4, windings W9 and W12, windings W5 and W8, windings W7 and W10, and windings W11 and W2 are connected in series, respectively, and these are connected in parallel between terminals T1 and T2. . An AC excitation power supply 5 is connected between terminals T1 and T2.
A and 5B (output e is e = Em · sin ωt) are connected in series. These AC excitation power supplies 5A, 5A
The terminal T3 to which B is commonly connected is grounded. In addition,
In this embodiment, the detection windings W1 to W12 are also provided with a function as an excitation winding. However, as in the case of the conventional example, both the excitation winding and the detection winding are provided in one stator magnetic pole. Of course, it is also possible to wind.

The magnetic poles P1, P4, P5, P of the stator 11
8, P9 and P12 and the teeth (protrusions) of the rotor core 13
Is based on the tooth pitch of the rotor core 13 (one period of change of the rotor radius) as follows. That is, as shown in FIG. 13, since the magnetic pole P1 is directly opposed to the tooth portion 13a of the rotor core 13, the shift pitch is zero. The shift pitch is (3/6) at the magnetic pole P4, and the shift pitch is (4 /
6), the deviation pitch is (1/6) in the magnetic pole P8, and the magnetic pole P9
In the magnetic pole P12, the shift pitch is (5/6).

On the other hand, the teeth 2 of the rotor core 23 shown in FIG.
The number 3a is set so as to satisfy the relationship of the expression (1) ′. Therefore, the stator poles P2, P3, P
The positional relationship between each of the small teeth 6 formed on P6, P7, P10 and P11 and the rotor teeth 23a is as follows based on the tooth pitch of the rotor teeth 23a. That is, the shift pitch is zero at the magnetic pole P7, the shift pitch is (3/6) at the magnetic pole P10, and the shift pitch is (4) at the magnetic pole P11.
/ 6), the deviation pitch of the magnetic pole P2 is (1/6), and the magnetic pole P
3, the shift pitch is (2/6) and that of the magnetic pole P6 is (5/6).

From the positional relationship between the magnetic poles of the stators 11 and 12 and the teeth of the rotors 13 and 23, the self-inductances L1 to L12 of the detection windings W1 to W12 are expressed as follows. L1 = La · cos (2θm) + Lda (26) L4 = La · cos (2θm + π) + Lda (27) L5 = La · cos (2θm−2π / 3) + Lda (28) L8 = La · cos (2θm + π / 3) + Lda (29) L9 = La · cos (2θm + 2π / 3) + Lda (30) L12 = La · cos (2θm−π / 3) + Lda (() 31) L7 = Lb · cos (50θm) + Ldb (32) L10 = Lb · cos (50θm + π) + Ldb (33) L11 = Lb · cos (50θm−2π / 3) + Ldb (34) ) L2 = Lb · cos (50θm + π / 3) + Ldb (35) L3 = Lb · cos (50θm + 2π / 3) + Ldb (36) L6 = Lb · cos (50θm−π / 3) + Ldb・ (37) where La, Lb, Lda, Ldb: constant θm: Rotation angle of rotor 30 from the reference position (mechanical angle)

FIG. 16 shows the self inductance L1,
The state of change of L4, L5, L8, L9 and L12 is shown. Other self inductances L7, L10, L1
1, L2, L3 and L6 also change in a similar manner. However, the self inductances L7, L10, L11,
Changes in L2, L3 and L6 are represented by L1 in FIG.
To L7, L4 to L10, L5 to L11, L8 to L
2, L9 to L3, L12 to L6, La to Lb,
Lda is replaced with Ldb, and 180 ° is replaced with 7.2 °.

Output signal voltages V1, V2 and V3 appearing at output terminals T4, T5 and T6 and output signal voltages V4 appearing at output terminals T7, T8 and T9 in FIG.
V5 and V6 are expressed as follows based on the above equations (26) to (37), respectively.

V1 = Ka · sinωt · cos (2θm) (38) V2 = Ka · sinωt · cos (2θm + 2π / 3) (39) V3 = Ka · sinωt · cos (2θm−2π / 3) ) (40) V4 = Kb · sinωt · cos (50θm) (41) V5 = Kb · sinωt · cos (50θm + 2π / 3) (42) V6 = Kb · sinωt · cos (50θm) -2π / 3) (43) where Ka and Kb are constants

As is apparent from the above equations (38) to (43), the variable magnetic resistance type position detector according to the fourth embodiment has a function as a variable magnetic resistance type synchro. Here, a description will be given of a case where the variable magnetoresistive synchro is mounted on a three-phase permanent magnet type motor having P = 2 (four poles). A signal voltage V obtained by synchronously detecting the output signal voltages V1, V2, and V3 by a synchronous detection unit (not shown).
As shown in FIG. 17, 1 ', V2', and V3 'are phase differences 1 whose periods coincide with the change periods of the surface magnetic flux of the motor rotor.
This is a 20-degree three-phase signal.

Therefore, the signal voltages V1 ', V
2 ′ and V3 ′ can be used as an excitation switching signal of a motor drive circuit or a current command signal of each phase, whereby the configuration of the drive circuit can be simplified. Further, the signal voltages V1 ', V2', V3 'can be used for detecting a rotor magnetic pole position of the motor. That is, the processing means shown in FIG. 27 can be applied by converting the three-phase signal into a two-phase resolver signal using a Scott transformer or the like. Also,
FIG. 27 shows two signal voltages selected from the three-phase signal voltages V4, V5, and V6, for example, the signal voltages V4 and V6 or the two-phase resolver signal converted by the Scott transformer or the like. The electric angle θb can be detected by the processing by the processing means.

However, when the above signal voltages V4 and V6 are used, since the phase difference between them is 120 degrees, the electric angle is calculated by calculating the arc tangent of the value obtained based on the following equation (44). θb is detected. tan θb = {(V6 / V4) + cos120 °} / sin120} (44) Then, as shown in the following equation (45), the detected electrical angle θb
Is divided by the shaft multiple angle 50 to obtain the mechanical angle θm. θm = θb / 50 (45)

FIG. 18 shows the relationship between the electrical angle θb and the mechanical angle θm. For example, the detection resolution of the electrical angle θb is 1
In this case, the actual rotation angle θm detection resolution is 1/50 = 0.02 °. That is, angle detection with extremely high resolution becomes possible. Further, the output signal voltage V
The signal voltages V4 ', V5', and V6 'obtained by synchronously detecting the signals V4, V5, and V6 are sine-wave signals whose phases are shifted from each other by 120 electrical degrees in 50 cycles per motor rotation. Therefore, this embodiment can also be used as a magnetic encoder or FG (frequency generator).

(Fifth Embodiment) FIGS. 19 and 20 show a fifth embodiment of the magnetoresistive position detection according to the present invention having a function as a variable magnetoresistive synchro. In this embodiment, as shown in FIG. 19, the rotor core 13 of the first position detection unit 10 has four teeth 13b.
0, the rotor core 2 of the second position detection unit 20
3 has 100 teeth 23b. Further, a total of twelve stator poles P1, P4, P5, P8, P9, P12, P13, P1
6, P17, P20, P21, and P24, and the same number of stator magnetic poles P2, P3, P6, P7, P10, P11, P1
4, P15, P18, P19, P22 and P23.

The excitation windings W10 to W240 are wound around the magnetic poles P1 to P24, respectively, and the detection windings W1 to W24 are wound, respectively, and these are connected in the manner shown in FIG. . That is, the excitation windings W10 to W240 are connected to the AC excitation power supply 5 (the output e is e = Em
(Sinωt) is connected in series between one end and the other end. Further, the detection windings W1, W4, W13, W16 are mutually
The detection windings W9, W12, W21, and W24 and the detection windings W5, W8, W17, and W20 are connected in series.

In order to avoid complicating the drawing, FIG.
0 are not shown for connection of the detection windings of the second position detection unit 20, but the connection diagram of these detection windings is not shown in FIG. The connection diagram of the windings is rotated by 360/4 = 90 degrees.
That is, the connection diagram is obtained by replacing the winding W1 with the winding W7, the winding W4 with the winding W10, and the winding W5 with the winding W11. In this embodiment, the stator 11
In addition, independent excitation windings and detection windings are wound around the respective magnetic poles, and as shown in FIG. 15, windings serving both as excitation windings and detection windings are wound around these magnetic poles. It is also possible to turn.

As is clear from the above description, in the fifth embodiment, the number P of the teeth 13b of the rotor core 13 (the number of periodic changes in the radius of the rotor core 13) is P = 4, 1) The value Z (the number of periodic changes in the radius of the rotor core 23) given by the equation (1) ′ is Z = (6 × n ± + 1) × P = (6
× 4 + 1) × 4 = 100, the numerical value N given by the above equation (3) ′ is N = 6 × 4 = 24, the numerical value a given by the above equation (5) is a = 2, and the above (7) 'The numerical value θp given by the equation is set to θp = 360/4 = 90 degrees.

The signal voltages V1, V2, and V3 obtained by the respective detection windings of the first position detecting section 10 are synchronously detected by a synchronous detecting section (not shown), and the signal voltages V1 ', V
2 ′, V3 ′. These signal voltages V1 ',
Since V2 'and V3' are three-phase signals having a phase difference of 120 degrees and a cycle corresponding to a change cycle of the surface magnetic flux of the rotor of the three-phase permanent magnet motor, the excitation switching signal of the motor drive circuit or the current of each phase is used. It can be used as a command signal.

Then, two signal voltages selected from V4, V5, and V6 (not shown in FIG. 21) obtained by the detection winding of the second position detection unit 10 or the three-phase signal is output. The electrical angle θb can be detected by processing the two-phase signal voltage converted by the Scott transformer or the like by processing means as shown in FIG. In this embodiment, the axis double angle of the second position detection unit 20 is 100X. Therefore, the relationship between the detected electrical angle θb and the corresponding mechanical angle θm is expressed by the following equation (46). θm = θb / 100 (46)

(Sixth Embodiment) FIGS. 22 and 23 show a sixth embodiment of a magnetoresistive position detector according to the present invention having a function as a variable magnetoresistive synchro. This sixth
In the embodiment, the number of periodic changes P of the radius of the rotor
Is P = 5, and the numerical value Z given by the equation (1) ′ is Z =
(6 × n ± 1) × P = (6 × 1-1) × 5 = 25, and the numerical value N given by the equation (3) ′ is N = 6 × 5 = 30.
The value a given by the above equation (5) is a = 2, and the value θp given by the above equation (7) ′ is θp = 360/5 =
Each is set to 72 degrees.

That is, as shown in FIG. 22, the rotor core 13 constituting the first position detecting section 10 has five teeth 1
As shown in FIG. 23, the rotor core 23 constituting the second position detecting unit 20 has 25 teeth 23c.
have. Then, a numerical value N (= 30) is assigned to the stator 11.
6a (= 12) fewer magnetic poles P3, P6, P
7, P9, P10, P12, P15, P18, P19,
P21, P22 and P24 are formed, and the same number of magnetic poles P1, P2, P4, P5, P8, P
11, P13, P14, P16, P17, P20 and P23 are formed. The above magnetic poles P1 to P2
4, a pair of an excitation winding and a detection winding or a detection winding which doubles as an excitation winding is wound, but this winding is omitted in FIGS.

In the sixth embodiment, the second position detector 2
The axis double angle of 0 is 25X. Therefore, the relationship between the electrical angle θb detected by the second position detection unit 20 and the corresponding mechanical angle θm is expressed by the following equation (47). θm = θb / 25 (47)

(Embodiment 7) FIG. 24 shows a seventh embodiment of the magnetoresistive position detector according to the present invention. In the seventh embodiment, as is apparent from a comparison with FIG. 1, the stator magnetic pole portion 12 of the first position detecting section 10 and the stator magnetic pole section 22 of the second position detecting section 20 have a single fixed position. Child yoke 400
Is shared. According to this configuration, the stator can be made smaller and lighter.

[0071]

According to the first and third aspects of the present invention, the number of pole pairs P
When combined with the two-phase permanent magnet type motor of
The period of the output signal voltage of the first position detection unit of (1) matches the period of change of the surface magnetic flux of the motor rotor. Therefore, the magnetic pole position of the motor rotor can be detected based on the output signal voltage of the first position detector, and this output signal voltage can be used as a current command signal for each phase of the motor. . In addition, a high detection resolution can be obtained by adopting a large value as the axis double angle Z of the second position detection unit. According to the second and fifth aspects of the present invention, the stator iron plates of the first position detecting section and the second position detecting section can be of the same shape, so that the stator die is one.
The advantage of manufacturing that only the type is required is obtained. Claim 4,
According to the sixth aspect of the invention, when combined with a three-phase permanent magnet type motor having the number of pole pairs P, the output signal voltage of the first position detection unit having the double shaft angle P coincides with the change period of the surface magnetic flux of the motor rotor. Since the three-phase signal voltage is obtained, the calculation of the electrical angle and the process of reading each phase current command value from the memory are not required, and the excitation switching circuit of the motor driving means is simplified. By adopting a large value as the axis double angle Z of the position detection unit, a high detection resolution can be obtained. According to the invention of claim 7, it is possible to select an advantage in manufacturing that only one kind of stator iron plate is required, or an advantage in characteristics by using two kinds of stator iron plates according to each axis double angle. Can be. According to the invention of claim 8, the length in the axial direction can be reduced.

[Brief description of the drawings]

FIG. 1 is a first view of a variable magnetoresistive position detector according to the present invention.
The longitudinal section showing an example.

FIG. 2 is a plan view showing a configuration of a first position detection unit in the first embodiment.

FIG. 3 is a plan view showing a configuration of a second position detection unit in the first embodiment.

FIG. 4 is a connection diagram of windings according to the first embodiment.

FIG. 5 is a graph showing a variation of a self-inductance of a winding.

FIG. 6 is a block diagram of a means for detecting an electrical angle.

FIG. 7 is a graph showing a relationship between an electrical angle and a mechanical angle.

FIG. 8 is a plan view showing a first position detecting unit according to a second embodiment of the present invention.

FIG. 9 is a plan view showing a second position detector in the second embodiment.

FIG. 10 is a wiring diagram of windings according to the second embodiment.

FIG. 11 is a plan view showing a first position detector in a third embodiment of the present invention.

FIG. 12 is a plan view showing a second position detection unit in the third embodiment.

FIG. 13 is a plan view showing a first position detection unit in a fourth embodiment.

FIG. 14 is a plan view showing a second position detection unit in the fourth embodiment.

FIG. 15 is a connection diagram of windings according to a fifth embodiment.

FIG. 16 is a graph showing a change mode of a self-inductance of a winding.

FIG. 17 is a waveform chart of an output signal voltage of the first position detection unit.

FIG. 18 is a graph showing a relationship between an electrical angle and a mechanical angle.

FIG. 19 is a plan view showing a first position detection unit according to a fifth embodiment of the present invention.

FIG. 20 is a plan view showing a second position detector in the fifth embodiment.

FIG. 21 is a wiring diagram of a winding in the fifth embodiment.

FIG. 22 is a plan view illustrating a first position detection unit according to a sixth embodiment of the present invention.

FIG. 23 is a plan view showing a second position detector in the sixth embodiment.

FIG. 24 is a longitudinal sectional view showing a seventh embodiment of the present invention.

FIG. 25 is a plan view showing the structure of a conventional variable magnetoresistive resolver.

FIG. 26 is a wiring diagram of a winding in a conventional resolver.

FIG. 27 is a block diagram of a means for detecting an electrical angle.

FIG. 28 is a block diagram illustrating a relationship between an electrical angle and a mechanical angle.

[Explanation of symbols]

 Reference Signs List 4 Rotation axis 6 Small teeth 7, 8 Stator yoke 10 First position detector 11, 21 Stator 12, 22 Stator magnetic pole 13, 23 Rotor core 13a, 23a Teeth 20 Second position detector 30 Rotor P1-P24 Magnetic pole W1-W24 winding W10-W240 winding

Claims (8)

[Claims] 1. A first rotor part whose radius changes periodically P times per rotation as a function of mechanical angle, and a 4a disposed opposite to the rotor part and wound around each of them. A first position detector comprising a first stator having a plurality of stator poles; a second rotor section having a radius that varies periodically Z times per revolution as a function of mechanical angle; A second position detecting unit comprising a second stator having 4a stator magnetic poles disposed opposite to the rotor unit and having windings wound therearound, the first position detecting unit comprising: And the second position detection unit are arranged so as to share a rotation axis, and so that the stator magnetic poles of the first stator and the second stator do not overlap with each other in the axial direction. Wherein said numerical values P, a and Z are set as follows: Mold position detector. P: an integer of 1 or more a: an integer that satisfies a = 1 when P = 1, and satisfies a ≦ P / 2 when P ≠ 1 Z: satisfies the following equation Z = (4n ± 1) P where n is an integer of 1 or more 2. The 4a stator magnetic poles provided on the first and second stators have the same arrangement position in the circumferential direction, and are arranged at an equal angular pitch. And radially protrude inward from 4a positions among the N divided positions. The first and second stators are arranged such that one of them is θp degrees apart from the other in order to prevent the stator magnetic poles from overlapping with each other. 2. The variable magnetic resistance type position detector according to claim 1, wherein the numerical value N and the angle [theta] p are set as follows. N: When P = 1, N = 4 × 2 = 8 When P ≠ 1, N = 4P θp: When P = 1, θp = (360/8) degrees When P ≠ 1, θp = (360 / P) degrees 3. A permanent magnet type motor having a number of pole pairs and having a permanent magnet in a rotor, wherein a detection signal of the first position detection unit is used to detect a rotor magnetic pole position of the motor. 2. A variable magnetoresistive position detector according to claim 1, wherein: 4. A first rotor part whose radius changes periodically P times per rotation as a function of mechanical angle, and 6a each of which is arranged opposite to the rotor part and has a winding wound therearound. A first position detector comprising a first stator having a plurality of stator poles; a second rotor section having a radius that varies periodically Z times per revolution as a function of mechanical angle; A second position detection unit comprising a second stator having 6a stator magnetic poles disposed opposite to the rotor unit and having windings wound therearound, and And the second position detection unit are arranged so as to share a rotation axis, and so that the stator magnetic poles of the first stator and the second stator do not overlap with each other in the axial direction. Wherein said numerical values P, a and Z are set as follows: Mold position detector. P: an integer of 1 or more a: an integer that satisfies a = 1 when P = 1, and satisfies a ≦ P / 2 when P ≠ 1 Z: satisfies the following equation Z = (6n ± 1) P where n is an integer of 1 or more 5. The 6a stator magnetic poles provided on the first and second stators have the same arrangement position in the circumferential direction, and the annular stator yoke portion has an equal angular pitch. Radially protrudes inward from 6a positions among the N-divided positions of the first and second stators. The first and second stators are arranged so that one of them is θp degrees apart from the other in order to prevent overlapping of the mutual stator magnetic poles. 5. The variable magnetoresistive type position detecting unit according to claim 4, wherein the numerical value N and the angle θp are set as follows. N: When P = 1, N = 6 × 2 = 12 When P ≠ 1, N = 6P θp: When P = 1, θp = (360/12) degrees When P ≠ 1, θp = (360 / P) degrees 6. The number of pole pairs P having a permanent magnet in the rotor is 3.
5. The variable magnetoresistive type according to claim 4, wherein the variable position sensor is provided in a phase permanent magnet type motor, and a detection signal of the first position detecting unit is used for detecting a rotor magnetic pole position of the motor. Position detector. 7. A small stator tooth having a tooth pitch corresponding to the Z teeth of the second rotor portion is formed at least on an inner peripheral surface of a stator magnetic pole of the second stator. The variable magnetoresistive position detector according to claim 1 or 4, wherein 8. The variable magnetoresistive position detector according to claim 1, wherein the first and second stators integrally or commonly share a stator yoke.