JP3309025B2 - Reluctance type resolver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reluctance resolver provided in a motor or the like and used for detecting an angle of a rotary shaft or the like.

[0002]

2. Description of the Related Art FIG. 4 shows an example of a conventional reluctance resolver. With respect to the center O of the rotating shaft 7, the circular rotor 2 is X0
The center is the center O1. Further, the magnetic poles 4a, 4b, and 2 are provided around the rotation shaft 7 and the circular rotor 2 in two directions (X direction and Y direction in the drawing) orthogonal to the axis O.
A stator core 4 having 4c and 4d is arranged.
Each magnetic pole is provided with an exciting coil 5a, 5b, 5c, 5d and a detecting coil 6a, 6b, 6c, 6d. The circular rotor 2 and the stator core 4 are made of a magnetic material. Since the circular rotor 2 is eccentric with respect to the center O of the rotating shaft 7, when the rotating shaft 7 rotates, the gap between the circular rotor 2 and the stator core 4 changes.

When the exciting coils 5a, 5b, 5c, 5d connected as shown in FIG. 8 are excited by an AC voltage, magnetic flux is applied to the detecting coils 6a, 6b, 6c, 6d in proportion to the reluctance fluctuation. By changing,
Ideally, an output waveform amplitude-modulated to a sine wave or a cosine wave according to the rotation angle can be obtained. That is, the excitation coils 5a and 5c, 5b and 5d, and the detection coils 6a and 6c, 6b and 6d are each paired. The differential output of each of the detection coil pairs 6a, 6c and 6b, 6d is used as an output waveform. In addition, a sine wave,
By performing an interpolation operation from the output waveform of the cosine wave, the angular position of the rotating shaft 7 can be obtained. The device shown in FIG. 4 is a so-called resolver having a so-called shaft double angle of 1 ×, in which the cycle of the sine wave and cosine wave corresponds to one rotation of the rotating shaft 7.

[0004]

However, the magnetic pole 4
Since a, 4b, 4c, and 4d have a predetermined length in the circumferential direction, and there is leakage of magnetic flux, the output waveform from the detection coil is an ideal sine wave or cosine wave. The resulting waveform contains harmonic distortion. This harmonic distortion is a permeance error. This permeance error is
When the angular position of the rotating shaft 7 is obtained by the interpolation operation, it causes an angular error. The ratio of the permeance error is different depending on the gap between the rotor and the stator magnetic pole. FIG. 5 shows output waveforms obtained by the two rotors 2 and 3 having different diameters while the eccentricity X0 shown in FIG. 4 is constant.

That is, if the gap between the rotor and the stator magnetic poles is narrow as in the case of the rotor 2, the output waveform contains many permeance errors as shown in FIG. 6, but the amplitude of the fundamental wave (AC component) is increased. Signal. On the other hand, if the gap between the rotor and the stator magnetic poles is wide as in the case of the rotor 3, a sine wave with a small permeance error can be obtained in the output as shown in FIG. 7, but the amplitude of the fundamental wave component decreases. Would. As described above, increasing the amplitude of the fundamental wave component of the output waveform is inconsistent with decreasing the permeance error, and there has been a problem that both cannot be at a satisfactory level. Further, widening the gap between the rotor and the stator magnetic poles has a disadvantage that the S / N ratio of the output signal is deteriorated and the angle cannot be detected with high accuracy. Is not practical.

Accordingly, an object of the present invention is to reduce the gap between the rotor and the stator poles while keeping the eccentricity of the rotor constant, and to increase the amplitude of the fundamental wave component of the output waveform even if the permeance error is to be increased. Is to obtain a sinusoidal wave with a small number of sine waves.

[0007]

In order to solve the above-mentioned problems, a reluctance resolver according to the present invention comprises a rotor provided eccentrically with respect to a rotating shaft by a predetermined amount, and a plurality of resolvers fixedly arranged around the rotor. And a reluctance resolver that detects the amount of movement of the rotor as a change in reluctance between the rotor and the stator, and detects the rotational position of the rotating shaft. In order to cancel the permeance error of the detection waveform, the shape is such that a plurality of concave portions and convex portions smaller than the eccentric amount are provided with respect to the perfect circle. Further, the plurality of detection coils form a plurality of detection coil pairs arranged with a phase of 180 ° of the detection waveform, and a change in reluctance is detected as a differential value of the detection coils forming the pair, and the outer circumference of the rotor is detected. The shape may be such that a concave portion and a convex portion are provided with respect to a perfect circle so as to cancel the permeance error of the odd-order component. Further, the outer peripheral shape of the rotor may be a shape in which three concave portions and three convex portions are provided with respect to a perfect circle, that is, a total of six locations so as to cancel the permeance error of the third order component.

[0008]

According to the present invention, the amplitude of the fundamental wave component is increased in the output waveform by the shape action of the plurality of concave and convex portions provided on the rotor so as to cancel the main component of the permeance error of the output waveform. In addition, it is possible to achieve both features that are closer to a sine wave and have less permeance error.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a reluctance type resolver having a 1X double angle of angle according to the present invention will be described below with reference to FIGS. 1, 2, 3 and 6. FIG. FIG. 1 shows a reluctance resolver according to the present embodiment. The same components as those of the conventional device shown in FIG. 4 are denoted by the same reference numerals, and description thereof is omitted. What is characteristic in the present embodiment is that the permeance error correcting rotor 1 eccentric with respect to the center O of the rotating shaft 7.
(Hereinafter, referred to as deformed rotor 1) is circular (in the figure,
(Shown by broken line 2). Similarly to the conventional apparatus, when the rotating shaft 7 rotates, the deformed rotor 1 is eccentric by X0 with respect to the center O of the rotating shaft 7, so that the gap between the deformed rotor 1 and the magnetic poles 4a, 4b, 4c, and 4d of the stator 4 is increased. Changes. Therefore, the excitation coils 5a, 5b, 5c, 5c connected as shown in FIG.
When d is excited by an AC voltage, the detection coils 6a, 6
The output waveforms b, 6c, and 6d can be amplitude-modulated into sine waves or cosine waves according to the rotation angle due to fluctuations in reluctance.

FIG. 6 shows the permeance error component of the output waveform of the conventional circular rotor 2.
The outer peripheral shape of the deformed rotor 1 is determined so as to reduce the third-order component that is the main component among the odd-order components. As a means, the shape is such that a concave portion is added to the deformed rotor 1 at a position where the permeance error of the third-order component included in the output waveform is maximized. Here, in the case where the angle detection is performed by performing an interpolation operation using a differential output from a coil output having a phase shift of 180 °, an odd number component is considered in principle in consideration of the fact that the permeance error of the even order component is canceled out. We focus on the next component. Now, it is assumed that the deformed rotor 1 is eccentric with respect to the center O of the rotating shaft 7 by X0 in the X-axis direction. The outer peripheral shape of the deformed rotor 1 before the eccentricity is defined by the following equation by the distance R from the centroid in the rotation axis direction and the angle θ based on the eccentric direction (the X-axis direction in this embodiment).

R (θ) = R0 + R3 cos (3θ + α) R0: radius of perfect circle R3: size of concave and convex portions added to perfect circle to reduce permeance error of third order component, Where R3 ≦
X0 / 2 α: phase angle

At an angle represented by the above formula with respect to a perfect circle having a radius R0, the concave portion and the convex portion are each 3
By decentering the deformed rotor 1 before decentering provided at a total of six points by X0 in the X-axis direction, the output waveform becomes as large as that of the conventional circular rotor 2 as shown in FIG. , And the permeance error of the third-order component can be significantly reduced as shown in FIG. As a result, the output waveform increases the amplitude of the fundamental wave component, is closer to a sine wave, and can obtain a waveform with less permeance error.

According to this embodiment configured as described above,
Even when the gap between the rotor and the stator magnetic pole is narrowed to increase the amplitude of the fundamental wave component of the output waveform, the permeance error is caused by the action of the plurality of concave and convex portions provided on the outer periphery of the deformed rotor 1. Sinusoidal wave with a small number of Therefore, the S / N ratio of the output waveform can be improved, and highly accurate angle detection can be realized.

In this embodiment, the deformed rotor 1 has an outer peripheral shape in which the permeance error of the third-order component is reduced. However, the same means can be applied when other permeance error components are reduced. . For example, when the permeance error of the fifth-order component and the second-order component is to be reduced in addition to the third-order component, the outer peripheral shape of the deformed rotor 1 before the eccentricity is defined by the following equation under the same conditions as in the above embodiment. Is done.

## EQU2 ## R (θ) = R0 + R2 cos (2θ + α) + R3 cos
(3θ + β) + R5 cos (5θ + γ) R0: radius of perfect circle R2, R3, R5: concave and convex parts added to perfect circle to reduce permeance error of second, third and fifth order components Size of part, but R2 ≦ X0 / 2, R3 ≦ X0 / 2, R5
≦ X0 / 2 α, β, γ: phase angle

By arranging the deformed rotor 1 having the concave portion and the convex portion at the eccentric position O1 at the angle represented by the above equation, the amplitude of the fundamental wave component is increased, and the output waveform with less permeance error is obtained. Obtainable. Generally, the amplitude of the fundamental wave component of the output waveform is determined by the eccentricity of the rotor,
Since the permeance error is determined by the minimum gap between the rotor and the stator magnetic poles and is smaller than the amplitude of the fundamental wave of the output waveform, the size of the concave and convex portions to be added is always smaller than the eccentricity. It is effective that the constant Rx (X is an order) in the above equation is determined by a magnetic field analysis such as a finite element method. In this case, it is necessary to consider narrowing down the constant Rx from a value smaller than the eccentric amount as described above. When a plurality of orders are reduced as in this embodiment, the constant Rx needs to be determined in order from the lower order, such as R2 first, then R3 and R5.

FIG. 8 shows an example of the stator coil of the reluctance resolver. However, the present invention is not limited to this coil type, but can be applied to various coil types. For example, the present invention is also applicable to a coil of a type that serves both as an excitation coil and a detection coil.

[0016]

As described above, according to the reluctance resolver of the present invention, the outer peripheral shape of the conventional eccentric circular rotor is formed with a plurality of concave portions and convex portions so as to reduce the permeance error. By deforming to the provided shape, a waveform closer to a sine wave with a small permeance error can be obtained as an output waveform, and as a result, the accuracy of angle detection of the resolver can be improved.

[Brief description of the drawings]

FIG. 1 shows a preferred embodiment according to the present invention, which is a double shaft angle 1;
3 is a configuration diagram of a reluctance resolver of X. FIG.

FIG. 2 is a diagram comparing an output waveform from a permeance error correction rotor of the present embodiment with an output waveform from a circular rotor.

FIG. 3 is a diagram illustrating a permeance error component of an output waveform according to the present embodiment.

FIG. 4 is a configuration diagram of a conventional reluctance resolver having a shaft multiple of 1 ×.

FIG. 5 is a diagram showing output waveforms of two types of conventional circular rotors having different diameters.

FIG. 6 is a diagram showing a permeance error component of the output waveform of the conventional device, particularly when the gap between the rotor and the stator magnetic pole is small.

FIG. 7 is a diagram illustrating a permeance error component of an output waveform of a conventional device, particularly when a gap between a rotor and a stator magnetic pole is large.

FIG. 8 is a connection diagram of an excitation coil and a detection coil in the present embodiment and a conventional example.

[Explanation of symbols]

1 Permeance error correction rotor, 2 circular rotor, 4
Stator core, 4a, 4b, 4c, 4d Stator magnetic pole, 5a, 5b, 5c, 5d Exciting coil, 6a, 6
b, 6c, 6d Detection coil, 7 rotation axis

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) G01D 5/00-5/62 H02K 24/00 G01B ⁷ /00-7/34

Claims (3)

(57) [Claims] A rotor provided eccentrically with respect to a rotation axis by a predetermined amount; and a stator fixedly disposed around the rotor and including a plurality of detection coils, and moving the rotor by an amount corresponding to the rotor and the stator. A reluctance resolver that detects the change in reluctance during the rotation and detects the rotational position of the rotating shaft, wherein the outer peripheral shape of the rotor is such that the amount of eccentricity with respect to a perfect circle is canceled so as to cancel a permeance error of a detected waveform. A reluctance type resolver having a shaft multiple of 1X, wherein the shape is provided with a plurality of concave portions and convex portions smaller than the above. 2. The reluctance resolver according to claim 1, wherein the plurality of detection coils have a detection waveform of 180 °.
A plurality of detection coil pairs arranged with the phase of are formed, a change in reluctance is detected as a differential value of the detection coils forming the pair, and the outer peripheral shape of the rotor cancels out permeance errors of odd-order components, A reluctance type resolver characterized by having a concave portion and a convex portion with respect to a perfect circle. 3. The reluctance resolver according to claim 2, wherein the outer peripheral shape of the rotor has three concave portions and three convex portions each with respect to a perfect circle so as to cancel the permeance error of the third order component. A reluctance type resolver characterized in that it has a shape provided in places.