JP7182489B2 - resolver and motor - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resolver for detecting the rotation speed and rotation angle of a motor, and a motor equipped with this resolver.

Conventionally, motors (especially brushless motors) are provided with detectors (sensors) for detecting the number of revolutions and the angle of rotation (rotational position). A resolver is used as a detector, and since this resolver has high angular resolution and robustness, it is used, for example, in a motor for driving a vehicle or a motor for power steering. For example, Patent Document 1 discloses a magnetic resolver that includes a rotor that rotates integrally with a rotating shaft of a motor, a stator provided with 4n (n is a natural number) salient poles, and a coil group wound around each salient pole. is disclosed. In this magnetic resolver, four phase coils, ie, 0° phase coil, 90° phase coil, 180° phase coil, and 270° phase coil, are excited with predetermined voltages and calculated to determine the rotational position and rotational speed of the rotor. The signal is calculated according to

JP-A-5-18980

By the way, in order to obtain the electrical angle from the resolver, a shaft double angle resolver having the same number as the number of pole pairs of the motor or a common divisor is required. For example, when the number of pole pairs of the motor is 7, the shaft angle multiplier of the resolver can be "7" which is the same number as the number of pole pairs or "1" which is a common divisor. Normally, in a resolver using four-phase coils as in Patent Document 1, the number of salient poles of the stator is set to be four times the shaft angle multiple of the resolver. For example, a resolver with a shaft angle multiple of 7 has 28 salient poles, and a resolver with a shaft angle multiple of 1 has four salient poles.

As described above, when the number of pole pairs of the motor is a prime number, there is a characteristic that the shaft angle multiplier of the resolver tends to increase, and there is a problem that the number of salient poles tends to increase. Since a coil is wound around each salient pole, an increase in the number of salient poles inevitably increases the number of places where the coil is wound. Furthermore, it is necessary to secure a space for winding the coil, which leads to an increase in the size of the resolver and an increase in cost. Further, as the rotor diameter of the resolver increases, the inertia increases, which may lead to a decrease in controllability.

The resolver in this case was devised in view of these issues, and aims to reduce the size and simplify the configuration of a resolver that uses a four-phase coil, and to suppress the deterioration of controllability due to an increase in inertia. be one of Another object of the motor of the present invention is to perform various controls with high accuracy. In addition to these purposes, it is also another object of the present invention to achieve functions and effects that are derived from each configuration shown in the modes for carrying out the invention described later and that cannot be obtained by conventional techniques. is.

(1) A resolver disclosed herein includes a rotor fixed to a shaft and a stator facing the rotor. The rotor has the same number of salient pole portions as the shaft angle multiplier of the resolver, and the stator has salient poles that are multiples of 4 and are radially projected from an annular core and arranged at predetermined intervals in the circumferential direction. , and a coil wound around each of the salient poles. The resolver includes, as the coils, a first phase coil with an electrical angle of 0 degrees, a second phase coil with an electrical angle of 90 degrees, a third phase coil with an electrical angle of 180 degrees, and a fourth phase coil with an electrical angle of 270 degrees. and the number of the salient poles is less than the value obtained by multiplying the shaft angle multiplier by 4 and is 12 or more, and the relationship between the shaft angle multiplier and the number of the salient poles is the mechanical angle A mechanical angle between the salient poles obtained by dividing 360 degrees by the number of the salient poles is set excluding an electrical angle of the rotor of 60 degrees multiplied by a natural number. If the figure formed by connecting the coils with straight lines is not point-symmetrical with respect to the rotation center of the shaft, and if the stator is bisected by an arbitrary diameter, it always straddles both areas. A turns factor is used to set the number of turns of the in-phase coils .

( 2 ) The salient poles are arranged at regular intervals in the circumferential direction, the shaft angle multiplier is 7, the number of salient poles is 12, and the relationship between the shaft angle multiplier and the number of salient poles is are preferably set so that the combinations of the electrical angle phase shift amounts of the phase coils with respect to the salient pole portions are all the same. That is, the combination of the electrical angle phase shift of the first phase coil with respect to the salient pole portion, the combination of the electrical angle phase shift of the second phase coil with respect to the salient portion, and the third phase coil with respect to the salient portion and the combination of the electrical angle phase shifts of the fourth-phase coil with respect to the convex pole portion are all set to be the same. It should be noted that the "electrical angle phase shift" here includes 0 (that is, a state in which there is no phase shift), and the "combination" includes the singular .

( 3 ) A second resolver disclosed herein includes a rotor fixed to a shaft and a stator facing the rotor. The rotor has the same number of salient pole portions as the shaft angle multiplier of the resolver, and the stator has salient poles that are multiples of 4 and are radially projected from an annular core and arranged at predetermined intervals in the circumferential direction. , and a coil wound around each of the salient poles. The resolver includes, as the coils, a first phase coil with an electrical angle of 0 degrees, a second phase coil with an electrical angle of 90 degrees, a third phase coil with an electrical angle of 180 degrees, and a fourth phase coil with an electrical angle of 270 degrees. and the number of the salient poles is less than the value obtained by multiplying the shaft angle multiple by four, the salient poles are arranged at different intervals in the circumferential direction, and the shaft angle multiple and the salient poles are arranged at different intervals. The relationship with the number is set by excluding the mechanical angle between the salient poles obtained by dividing the mechanical angle of 360 degrees by the number of the salient poles, excluding the electrical angle of the rotor of 60 degrees multiplied by a natural number, The electrical angle phase shift amount of each phase coil with respect to the salient pole portion is set to be zero.
( 4 ) The number of salient poles is 12 or more, and a figure formed when one of the four-phase coils is a target coil and the coils of the same phase adjacent in the circumferential direction are connected with straight lines is the above-mentioned If the shape is not point-symmetrical about the center of rotation of the shaft, and if the stator is divided in two by an arbitrary diameter, it always straddles both regions, the number of turns of the in-phase coils is set using a predetermined winding coefficient. It is preferable that

( 5 ) A motor disclosed herein includes the resolver according to any one of (1) to ( 4 ) above, a motor rotor rotating integrally with the shaft, and a motor stator fixed to a housing. ing.

According to the disclosed resolver, by setting the number of salient poles around which the coil is wound to be less than four times the shaft angle multiplier, it is possible to reduce the size of the resolver and simplify the configuration. Also, since an increase in the rotor diameter can be prevented, a decrease in controllability due to an increase in inertia can be suppressed.
Further, according to the disclosed motor, various controls such as position control and speed control can be performed with high accuracy.

FIG. 3 is a schematic cross-sectional view of the resolver according to the embodiment as seen from the axial direction; It is a typical sectional view showing a motor concerning an embodiment. 2 is a circuit diagram showing the configuration of an electric system of the resolver shown in FIG. 1; FIG. 3(a) and 3(b) are diagrams and a table for explaining a method of arranging coils of the resolver shown in FIG. 1. FIG. (a) and (b) are schematic diagrams for explaining a resolver setting method according to the embodiment. (a) and (b) are schematic diagrams for explaining a resolver setting method according to the embodiment. FIG. 4 is a schematic diagram for explaining the robustness of a resolver with four salient poles; FIG. 4 is a schematic diagram for explaining the winding number distribution of a resolver having 12 salient poles; FIG. 4 is a schematic diagram for explaining the winding number distribution of a resolver having 16 salient poles; FIG. 5 is a schematic cross-sectional view of a resolver according to a modification as seen from the axial direction;

A resolver and a motor as embodiments will be described with reference to the drawings. The embodiments shown below are merely examples, and there is no intention to exclude various modifications and application of techniques not explicitly described in the embodiments below. Each configuration of this embodiment can be modified in various ways without departing from the gist thereof. Also, they can be selected or combined as needed.

[1. Constitution]
[1-1. Basic structure of resolver]
The resolver according to this case is a variable reluctance type (VR type) resolver. That is, the cylindrical outer peripheral surface of the rotor (resolver rotor) facing each salient pole of the stator (resolver stator) is configured so that the distance from the rotation center of the shaft varies periodically in the circumferential direction. Rotation angle is detected by utilizing fluctuations in resolver output signals (hereinafter referred to as "resolver signals") due to changes in the distance (air gap) between the radially inner end surface and the cylindrical outer surface of the rotor.

FIG. 1 is a schematic plan view of the resolver 1 according to the present embodiment viewed from the axial direction, and shows only a shaft 9 (rotating shaft) in cross section. The resolver 1 of this embodiment is incorporated in a motor 10 as shown in FIG. 2, for example. The motor 10 is a brushless motor (for example, a servomotor) that includes a motor stator 11 fixed to a housing 13 , a motor rotor 12 that rotates together with a shaft 9 , and a resolver 1 built in the housing 13 . The resolver 1 is arranged on the shaft 9 of the motor 10 and detects the rotation angle (rotational position) of the motor 10 . In the present embodiment, an inner rotor type resolver 1 having a shaft angle multiple of 7 (a resolver 1 having a 7X structure) is exemplified. A symbol x is attached to the shaft double angle.

As shown in FIG. 1 , the resolver 1 includes a rotor 2 fixed to a rotatable shaft 9 and a stator 3 facing the rotor 2 . Since the resolver 1 of this embodiment is of the inner rotor type, the stator 3 is arranged around the rotor 2 (outside in the radial direction) so as to face it. A mounting hole 2h into which the shaft 9 is fitted is formed in the central portion of the rotor 2, and the central axis of the rotor 2 coincides with the rotation center C. As shown in FIG. The rotor 2 is configured by laminating a plurality of annular thin plates (steel plates) made of ferromagnetic material, for example.

The rotor 2 has the same number of salient pole portions 21 as the shaft angle multiplier x of the resolver 1 and arranged at regular intervals in the circumferential direction. That is, the rotor 2 of this embodiment is provided with seven salient pole portions 21 . Each convex pole portion 21 is a portion formed so as to protrude in an arc shape radially outward from a virtual circle centered on the rotation center C (a two-dot chain line in FIG. 1). All salient pole portions 21 have the same shape. As a result, the outer peripheral surface 2s of the rotor 2 has a tubular shape in which the distance from the rotation center C of the shaft 9 periodically varies in the circumferential direction.

The stator 3 has an annular core 31 , a plurality of salient poles 5 projecting radially from the core 31 and arranged at predetermined intervals in the circumferential direction, and a coil 4 wound around each salient pole 5 . The number of salient poles 5 (hereinafter referred to as "salient pole number s") is a multiple of 4 (4, 8, 12, 16, . For example, in the resolver 1 with the shaft angle multiplier x of 7, the number of salient poles s is set to a value less than 28 (any one of 4, 8, 12, 16, 20 and 24). The reason why even if the salient pole number s is set in this way, a resolver signal that fluctuates according to changes in the air gap can be output and the rotation angle can be detected in the same way as a conventional resolver using a four-phase coil. , will be described later.

The number of salient poles s in this embodiment is 12, and they are arranged at equal intervals in the circumferential direction (that is, at intervals of 30 mechanical degrees). That is, the resolver 1 of this embodiment is an equidistant resolver. Each salient pole 5 has a tooth portion 51 extending radially inward (toward the center of rotation C) from the core 31 and a wide wall portion 52 extending in the circumferential direction at the distal end portion of the tooth portion 51. It has a substantially T shape in plan view. The tooth portion 51 is a portion around which the coil 4 is wound, and the wall portion 52 is a portion that faces the outer peripheral surface 2s of the rotor 2 and receives magnetic flux. The spaces between salient poles 5 adjacent in the circumferential direction are called slots 6, and the number of salient poles s and the number of slots 6 are the same.

The resolver 1 of this embodiment is provided with 12 coils 4 . Each coil 4 is an input coil to which a current is applied, and is wound in opposite directions between adjacent salient poles 5 in the circumferential direction. The coils 4 include a coil 4A with an electrical angle of 0 degrees (hereinafter also referred to as "first phase coil 4A"), a coil 4B with an electrical angle of 90 degrees (hereinafter also referred to as "second phase coil 4B"), and an electrical angle of 180 degrees. The same number of coils 4C with an electrical angle of 270 degrees (hereinafter also referred to as "fourth phase coils 4D") are provided. In other words, the number of phase coils 4A to 4D is one quarter of the salient pole number s.

The resolver 1 of the present embodiment is provided with three first-phase coils 4A, second-phase coils 4B, third-phase coils 4C, and fourth-phase coils 4D. In-phase coils 4 are connected in series. The arrangement of the phase coils 4A to 4D will be described later.

Each wall portion 52 extends from the radially inner end portion of the tooth portion 51 to both sides along the circumferential direction (rotational direction). All the walls 52 have the same circumferential length. A radially inner end surface 5s of each salient pole 5 (a surface of the wall portion 52 facing radially inward) is positioned on a circle centered on the rotation center C. As shown in FIG. That is, the end faces 5s of the respective salient poles 5 of the present embodiment are arranged equidistantly from the center of rotation C and form arcs centered on the center of rotation C. As shown in FIG. An air gap is provided between each end surface 5 s and the outer peripheral surface 2 s of the rotor 2 .

[1-2. Circuit Configuration of Resolver]
FIG. 3 is a circuit diagram showing the configuration of the electrical system of the resolver 1. As shown in FIG. As shown in FIG. 3, one end 4e of the in-phase coil 4 wound around each salient pole 5 is connected to one terminal 40a of an AC power supply 40 (excitation power supply), and the other end 4f of the in-phase coil 4 is connected to They are connected to the other terminal 40b of the AC power supply 40 via shunt resistors 41A to 41D, respectively. Output terminals 42A-42D are provided between the phase coils 4A-4D and their shunt resistors 41A-41D, respectively.

Here, a sine wave signal is output from the output terminal 42A of the first phase coil 4A, and a sine wave signal having a phase opposite to that of the output terminal 42A is output from the output terminal 42C of the third phase coil 4C. In addition, a cosine wave signal is output from the output terminal 42B of the second phase coil 4B, and a cosine wave signal having a phase opposite to that of the output terminal 42B is output from the output terminal 42D of the fourth phase coil 4D.

Sine wave signals and cosine wave signals output from output terminals 42A to 42D of phase coils 4A to 4D are input to R/D (Resolver-Digital) converter section 7 . The R/D converter section 7 includes a first differential amplifier 71, a second differential amplifier 72, a phase shifter 73, and an adder 74. Then, angle calculation processing is performed.

The positive input terminal and negative input terminal of the first differential amplifier 71 are connected to output terminals 42A and 42C, respectively, and the positive input terminal and negative input terminal of the second differential amplifier 72 are connected to output terminals 42B and 42D. connected respectively. A phase shifter 73 for shifting the phase by 90 degrees is connected to the output terminal of the second differential amplifier 72 . Also, the output terminal of the first differential amplifier 71 is connected to the first input terminal of the adder 74 , and the output terminal of the phase shifter 73 is connected to the second input terminal of the adder 74 . As a result, the input signal is processed in the R/D converter section 7 .

[1-3. Relationship between shaft angle multiplier and number of salient poles]
As described above, the resolver 1 of the present embodiment exhibits the rotation angle detection function even though the salient pole number s is smaller than the value (4x) obtained by multiplying the shaft angle multiplier x by four. Hereinafter, how to set the relationship between the shaft angle multiplier x and the number of salient poles s of the resolver 1 to establish the resolver will be described together with the method of arranging the coil 4 .

First, taking as an example the resolver 1 shown in FIG. 1 with "the shaft angle multiplier x of 7 and the number of salient poles s of 12", which phase coils 4A to 4D are wound on which salient pole 5 is shown in FIG. Description will be made using a) and (b). As shown in FIG. 4(a), among the 12 salient poles 5, the position of the salient pole 5 located at the right end in the drawing is defined as a "reference position", and the positions of the salient poles 5 are 1 to 1 in counterclockwise order. Assign 12 numbers (salient pole numbers). For example, the salient pole 5 that is displaced counterclockwise by 30 mechanical degrees from the salient pole 5 at the reference position is defined as "salient pole No. 1". The salient pole 5 at the reference position is "No. 12". The relationship between the salient pole No. and the mechanical angle position is as shown in the table of FIG. 4(b).

Next, the electrical angle phase corresponding to the mechanical angle position of each salient pole 5 is obtained. The electrical angle phase corresponds to the value (product) obtained by multiplying the mechanical angle position (mechanical angle) by the shaft angle multiplier x. is a natural number). For example, salient pole No. 3 has a mechanical angle position of 90 degrees and an electrical angle phase of 270 degrees (=90×7-360), and salient pole No. 6 has a mechanical angle position of 180 degrees. The electrical angle phase is 180 degrees (=180×7-360×3).

Next, the same number of salient poles 5 having electrical angle phases closest to 0 electrical angle, 90 electrical angle, 180 electrical angle, and 270 electrical angle are selected and wound around each of the selected salient poles 5. 1, 2, 3, and 4 in order. For example, in the resolver 1 shown in FIGS. 4A and 4B, the salient poles 5 having electrical angle phases closest to 0 electrical angle are No. 12 (electrical angle phase=0) and No. 7 (electrical angle phase=0). 5 (electrical angle phase=330), the phase number of the coil 4 wound around these three salient poles 5 is set to "1". That is, these three salient poles 5 are wound with the first phase coil 4A having an electrical angle of 0 degrees.

Similarly, the salient poles 5 having electrical angle phases closest to 90 electrical degrees are No. 9 (electrical angle phase = 90), No. 4 (electrical angle phase = 120), No. 2 (electrical angle phase = 60), the phase number of the coil 4 wound around these three salient poles 5 is set to "2". A second phase coil 4B having an electrical angle of 90 degrees is wound around these three salient poles 5 .

Similarly, the salient poles 5 having electrical angle phases closest to 180 electrical degrees are No. 6 (electrical angle phase = 180), No. 1 (electrical angle phase = 210), No. 11 (electrical angle phase = 150), the phase number of the coil 4 wound around these three salient poles 5 is set to "3". A third phase coil 4C having an electrical angle of 180 degrees is wound around these three salient poles 5 .

Similarly, the salient poles 5 having electrical angle phases closest to 270 electrical degrees are No. 3 (electrical angle phase = 270), No. 10 (electrical angle phase = 300), No. 8 (electrical angle phase = 240), the phase number of the coil 4 wound around these three salient poles 5 is set to "4". A fourth-phase coil 4D having an electrical angle of 270 degrees is wound around these three salient poles 5 .

Next, the electrical angle phase shift amounts of the phase coils 4A to 4D are obtained. For example, focusing on the three salient poles 5 (No. 12, No. 7, and No. 5) with a phase number of 1, the electrical angle phase of the salient pole No. 12 is 0 degree. Even if the coil 4A with an angle of 0 degrees is arranged, no phase shift occurs. That is, the electrical angle phase shift amount of salient pole No. 12 is "0". On the other hand, since the electrical angle phase of the salient pole No. 7 is 30 degrees, if the coil 4A with the electrical angle of 0 degrees is placed at this position, an electrical angle phase shift of 30 degrees occurs. Similarly, since the electrical angle phase of salient pole No. 5 is 330 degrees, if the coil 4A with an electrical angle of 0 degrees is placed at this position, an electrical angle phase shift of -30 degrees occurs. That is, the electrical angle phase shift amount of salient pole No. 7 is "30", and the electrical angle phase shift amount of salient pole No. 5 is "-30".

In a similar manner, three salient poles 5 (No. 9, No. 4, No. 2) with a phase number of 2, three salient poles 5 (No. 6, No. 1, No. 11), and the three salient poles 5 (No. 3, No. 10, and No. 8) with a phase number of 4, the electrical angle phase shift amount is obtained. The electrical angle phase shift amount of each of the phase coils 4A to 4D corresponds to the magnitude of the electrical angle phase shift (rotor electrical angle phase) with respect to the salient pole portion 21 of the rotor 2. FIG.

Here, focusing on the combinations of the electrical angle phase shift amounts of the phase coils 4A to 4D, they are all the same combination of "0, 30, -30". In this way, even if there is an electrical angle phase shift between the respective coils of the phase coils 4A to 4D, the rotation angles of the phase coils 4A to 4D can be detected if the combination is the same for all four phases. There is, and it is established as a resolver. Therefore, the relationship between the shaft angle multiplier x and the number of salient poles s of the resolver is set so that the combinations of the electrical angle phase shift amounts of the phase coils with respect to the rotor (specifically, the salient pole portions) are all the same.

In order to be established as a resolver, the same number of salient poles having electrical angle phases closest to 0 electrical angle, 90 electrical angle, 180 electrical angle, and 270 electrical angle must be selected. Based on this point of view, conversely, the conditions that do not hold true for the resolver (hereinafter referred to as "impossible conditions") are clarified, and the shaft angle multiplier x and the number of salient poles s are set so as not to satisfy all the impossible conditions.

FIGS. 5(a), (b) and FIGS. 6(a), (b) are schematic diagrams for explaining the setting method of the resolver, and show impermissible conditions. As described above, the same number of four-phase coils must be arranged in the resolver, but depending on the relationship between the mechanical angle position of the salient poles and the electrical angle phase of the coils, some coils cannot be arranged.

5 ( As shown in a), all the coils are in the same phase, and other three-phase coils cannot be selected. The mechanical angle between adjacent salient poles can be expressed as 360/s. If the mechanical angle of 360/s is equal to the electrical angle of 360 degrees (360/x in mechanical angle), the impossibility 1 shown in FIG. 5A is met. Also, when the mechanical angle 360/s between the adjacent salient poles is equal to the value obtained by multiplying the electrical angle 360 degrees by a natural number n (720 electrical degrees, 1080 degrees, . . . ), the condition 1 is similarly met. .

Therefore, the impossibility 1 is represented by the following formula.
Impossible condition 1: x=ns (where n is a natural number)
For example, a combination of "axis multiple x=4, salient pole number s=4" or "axis multiple angle x=8, salient pole number s=4" does not work as a resolver.

For the mechanical angle between the adjacent salient poles to be equal to 180 electrical degrees of the rotor, as shown in FIG. cannot select the other two phase coils. That is, when the mechanical angle 360/s between the adjacent salient poles is equal to the electrical angle of 180 degrees (360/2x in mechanical angle), the impermissible condition 2 shown in FIG. 5B is met. Also, when the mechanical angle 360/s between the adjacent salient poles is equal to the value obtained by multiplying the electrical angle of 180 degrees by an odd number (540 degrees, 900 degrees, .

Therefore, the impossibility 2 is expressed as follows.
Impossible condition 2: 2x=(2n-1)s (where n is a natural number)
For example, a combination of "axis multiple x=4, salient pole number s=8" and "axis multiple angle x=6, salient pole number s=4" do not work as a resolver. In addition, a value obtained by multiplying the electrical angle of 180 degrees by an even number (360 degrees, 720 degrees, etc. in electrical angle) corresponds to the impossibility 1. FIG.

In addition, as shown in FIG. 6A, the mechanical angle between the adjacent salient poles is equal to 120 degrees in terms of the electrical angle of the rotor. A coil with an angle of 270 degrees can be selected, but a one-phase coil cannot be selected. Furthermore, in this case, the combinations of selectable three-phase coils with respect to the rotor are not the same. For example, as shown in FIG. 6A, when a coil is placed at a position where the electrical angle phase is 0 degree, the phase shift of the 0 degree coil is 0. On the other hand, when the coils are arranged at positions where the electrical angle phase is 90 degrees and 270 degrees, the phase shift of the 90-degree coil is 30 and the phase shift of the 270-degree coil is -30. The phase shift amount does not match.

That is, when the mechanical angle 360/s between the adjacent salient poles is equal to the electrical angle of 120 degrees (360/3x in mechanical angle), the impossibility 3 shown in FIG. 6A is met. Also, when the mechanical angle 360/s between the adjacent salient poles is equal to the value obtained by multiplying the electrical angle 120 degrees by a natural number n excluding a multiple of 3 (240 degrees, 480 degrees, 600 degrees, ... in terms of electrical angles) , also corresponds to impermissible condition 3.

Therefore, the impossibility 3 is represented by the following formula.
Impossible condition 3: 3x=n's (where n' is a natural number other than a multiple of 3)
For example, a combination of "axis multiple x=4, salient pole number s=12" and "axis multiple angle x=8, salient pole number s=12" do not work as a resolver. A value obtained by multiplying the electrical angle of 120 degrees by a multiple of 3 (a value obtained by multiplying the electrical angle by 3n, that is, an electrical angle of 360 degrees, 720 degrees, etc.) corresponds to the first impossibility.

In addition, as shown in FIG. 6B, for example, a coil (coil 6n in the figure) with an electrical angle of 0 degrees and an electrical A coil with an angle of 180 degrees (coil 6n+3 in the figure) can be selected. However, there are two coils with an electrical angle of 90 degrees and two coils with an electrical angle of 270 degrees. Specifically, the coils 6n+1 and 6n+2 are selected at an electrical angle of 90 degrees, and the coils 6n+4 and 6n+5 are selected at an electrical angle of 270 degrees. Therefore, the number of coils for all the four phases is not the same, and the resolver does not work.

In other words, when the mechanical angle 360/s between the adjacent salient poles is equal to the electrical angle of 60 degrees (360/6x in mechanical angle), the impossibility 4 shown in FIG. 6B is met. Also, when the mechanical angle 360/s between the adjacent salient poles is equal to the value obtained by multiplying the electrical angle of 60 degrees by 6n-1 or the value obtained by multiplying the electrical angle by 6n-5 (300 degrees, 420 degrees, ... in terms of electrical angle) also falls under the impossibility 4. Here, both 6n-1 and 6n-5 are represented by symbol m.

Therefore, the impossibility 4 is represented by the following formula.
Impossible condition 4: 6x=ms (however, m=6n-1 and 6n-5)
For example, the combination of "axis multiple x=10, salient pole number s=12" and "axis multiple angle x=14, salient pole number s=12" do not work as a resolver.

A value obtained by multiplying the electrical angle of 60 degrees by 2n (120 degrees, 240 degrees in electrical angle, etc.) corresponds to Impossible Condition 3, and a value obtained by multiplying the electrical angle of 60 degrees by 3n (180 degrees, 360 degrees in electrical angle, etc.) corresponds to the impossibility 2, and a value obtained by multiplying the electrical angle of 60 degrees by 6n (360 degrees, 720 degrees, etc. in terms of electrical angle) corresponds to the impossibility 1. In other words, in the formula expressing the impermissible condition 4, if m is expanded to all natural numbers n, the above impermissible conditions 1 to 3 are included. Therefore, the relationship between the resolver shaft angle multiplier x and the number of salient poles s is set except for the mechanical angle between adjacent salient poles, which is the rotor electrical angle of 60 degrees multiplied by the natural number n.

[1-4. number of turns distribution]
Here, a configuration for improving robustness of the resolver will be described. As shown in FIG. 1, when a resolver 1 is provided with a plurality of phase coils 4A to 4D, if there is symmetry in the arrangement of the phase coils 4A to 4D, fluctuations in the radial direction of the shaft, that is, axial runout occur. This suppresses fluctuations in the angle calculation result when In other words, robustness against axial vibration is improved.

FIG. 7 shows a schematic diagram of a resolver 1a with a shaft angle multiplier of x=5 and the number of salient poles of s=4, and a schematic diagram of a resolver 1b with a shaft angle multiplier of x=7 and the number of salient poles of s=4. Since each of these resolvers 1a and 1b is provided with only one coil 4A to 4D for each phase, there is no in-phase coil 4 on the opposite side (opposite side across the rotation center C). For example, focusing on the first-phase coil 4A indicated by the white circle, the straight line (one-dot chain line in the figure) that passes through the center of rotation C and connects the second-phase coil 4B and the fourth-phase coil 4D There is no one-phase coil 4A. Therefore, when the position of the rotation center C of the rotor deviates slightly (when shaft wobbling occurs), the angle calculation result may vary.

On the other hand, as shown in FIGS. 8 and 9, for example, when the resolver has a number of salient poles s of 12 or more and a coil 4 of the same phase exists on the opposite side, the axial deflection can be reduced by devising the number of turns. It may be possible to increase robustness against Specifically, when a figure formed by connecting in-phase coils 4 adjacent in the circumferential direction with a straight line satisfies both the following conditions 1 and 2, a predetermined winding number coefficient K By using , the robustness is improved.
Condition 1: The figure is not point-symmetrical about the center of rotation C. Condition 2: The figure must straddle both regions when the stator is bisected by an arbitrary diameter.

If Condition 1 is not satisfied, that is, if the in-phase coils 4 are arranged symmetrically about the rotation center C when the stator is viewed from the axial direction, it is not necessary to devise the number of turns of the in-phase coils 4. Even if blurring occurs, it is possible to cancel each other out. In other words, if the condition 1 is not satisfied, the winding coefficient K is not used because the robustness against axial vibration is high in the first place.

When condition 2 is not satisfied, that is, when there is no in-phase coil 4 on the opposite side (when the arrangement of the coils 4 is biased), similar to the resolvers 1a and 1b shown in FIG. , the turns factor K is not used. Note that the winding coefficient K is obtained in advance by experiments, simulations, or the like.

In the resolver 1f (shaft angle multiplier x=5, salient pole number s=12) and resolver 1g (shaft angle multiplier x=7, salient pole number s=12) shown in FIG. A figure connecting them with a straight line is an isosceles triangle that straddles an arbitrary diameter, as indicated by the solid line in the figure. Similarly, the other phase coils 4B to 4D also form isosceles triangles straddling arbitrary diameters. Therefore, both of these resolvers 1f and 1g satisfy the above conditions 1 and 2. For this reason, for example, in the resolvers 1f and 1g, if the number of turns of the first phase coil 4A located on the right side in the figure is Y1 and the number of turns of the two first phase coils 4A located on the left side in the figure is Y2, then the number of turns is Y1 is set to a value obtained by multiplying the number of turns Y2 by the number of turns coefficient K (Y1=Y2×K).

On the other hand, in the resolver 1h shown in FIG. 8 (axis multiple x=11, number of salient poles s=12), for example, a figure connecting the first phase coils 4A adjacent in the circumferential direction with a straight line is shown by a solid line in the figure. In addition, since it is an isosceles triangle that does not straddle any diameter, the above condition 2 is not satisfied. Therefore, in the resolver 1h, the winding number is set without using the winding number coefficient K.

In the resolver 1i (double angle x=5, number of salient poles=16) and resolver 1k (double angle x=7, salient pole number s=16) shown in FIG. A figure obtained by connecting the coils 4A with straight lines is a trapezoid extending over an arbitrary diameter, as indicated by the solid line in the figure. Similarly, the other phase coils 4B to 4D also have trapezoidal shapes extending over arbitrary diameters. Therefore, both of these resolvers 1i and 1k satisfy the conditions 1 and 2 above. Therefore, in the resolvers 1i and 1k as well, similar to the resolvers 1f and 1g described above, by setting the number of turns of the phase coils 4A to 4D using the winding number coefficient K, robustness can be improved.

On the other hand, in the resolver 1j shown in FIG. 9 (axis multiple x=6, number of salient poles s=16), for example, a figure connecting the first phase coils 4A adjacent in the circumferential direction with a straight line is shown by a solid line in the figure. Moreover, since it is a rectangle, it does not satisfy condition 1 above. Therefore, in the resolver 1j, the number of turns of each phase coil 4A to 4D should be set to be the same.

[2. action, effect]
(1) In the resolver described above, the number of salient poles 5 wound around the coil 4 is less than four times the shaft angle multiple (that is, the number of salient poles 5 is thinned out), thereby miniaturizing the resolver and simplifying the configuration. can be improved. Also, since an increase in the rotor diameter can be prevented, a decrease in controllability due to an increase in inertia can be suppressed.

(2) According to the resolver described above, as a combination of the shaft angle multiplier x and the salient pole number s, when the salient pole number s is a multiple of 4, "the mechanical angle between the adjacent salient poles is 60 in terms of the electrical angle of the rotor. A resolver with a simple configuration can be established by excluding "the product obtained by multiplying the natural number n".

(3) In the resolver described above, the relationship between the shaft angle multiplier x and the number of salient poles s is set so that the combinations of the electrical angle phase shift amounts of the phase coils 4A to 4D with respect to the salient pole portion 21 are all the same. It is Therefore, even if there is a phase shift with respect to the rotor (the salient pole portion 21), by making the combination of the phase shifts the same for all the four-phase coils 4A to 4D, a resolver with a simple configuration can be established. can.

(4) Furthermore, by setting all the combinations of the electrical angle phase shift amounts to be the same, the salient poles 5 of the resolver 1 can be arranged at equal intervals in the circumferential direction, as shown in FIG. 1, for example. In other words, the mechanical angles between the adjacent salient poles can all be made the same, so that the resolver 1 can be further miniaturized and simplified in configuration.

(5) In addition, in a resolver having a number of salient poles s of 12 or more, when both the above conditions 1 and 2 are satisfied, the number of turns of the coil 4 is set using the turns coefficient K, thereby improving robustness against axial runout. can be enhanced. For example, like the resolvers 1f and 1g shown in FIG. 8, when the arrangement of the phase coils 4A to 4D is an isosceles triangle straddling an arbitrary diameter when viewed in the axial direction, the number of turns on the vertex side with respect to the number of turns on the base side A resolver with high robustness can be realized by setting the number of turns using the winding number coefficient K that increases .

(6) In addition, since the rotation angle of the rotor (that is, the shaft 9) can be detected with high accuracy in a motor equipped with the resolver described above, various controls such as position control and speed control can be performed with high accuracy. can do.

[3. Modification]
Although the resolver described above has a plurality of salient poles arranged at equal intervals in the circumferential direction, the salient poles of the resolver may be arranged at different intervals in the circumferential direction. Hereinafter, the resolver 1' in which the intervals between salient poles adjacent in the circumferential direction are not uniform is also referred to as a resolver 1' with different intervals. FIG. 10 exemplifies a resolver 1' with a variable spacing of x=7 and the number of salient poles s=12. In addition, in the following description, the same reference numerals are given to the same configurations as in the above-described embodiment, and duplicate descriptions will be omitted.

In the differently-spaced resolver 1', the mechanical angle position of the salient poles 5 is set to a position that coincides with the rotor electrical angle phase. In other words, the electrical angle phase shift amounts of the phase coils 4A to 4D are all 0, and the combinations of the electrical angle phase shift amounts of the phase coils 4A to 4D are all the same. For example, focusing on the salient poles 5 around which the first phase coil 4A with an electrical angle of 0 degrees is wound, three straight lines L5, L7, and L12 (broken lines in the figure) connecting these salient poles 5 and the rotation center C passes through the tip of the salient pole portion 21 (the position where the tangent line of the salient pole portion 21 extends in the direction orthogonal to the radius of the rotor 2).

A method of setting the mechanical angle positions of the salient poles 5 in the differently-spaced resolver 1' as shown in FIG. 10 will be described. First, as in the equally-spaced resolver 1 described above, the position of one salient pole 5 is defined as a "reference position", and salient pole No. 1 is assigned to each salient pole 5. shake. Next, the electrical angle phase corresponding to the mechanical angle position of each salient pole 5 is obtained. Then, the same number of salient poles 5 having electrical angle phases closest to 0 electrical angle, 90 electrical angle, 180 electrical angle, and 270 electrical angle are selected and wound around each of the selected salient poles 5. 1, 2, 3, and 4 in order. The process up to this point is as shown in the table shown in FIG. 4(b).

Further, in the differently-spaced resolver 1', the mechanical angular positions of the salient poles 5 are shifted in the circumferential direction so that the electrical angle phase shift amounts of the phase coils 4A to 4D are zero. For example, focusing on three salient poles 5 [salient poles No. 12, No. 7, and No. 5 in FIG. is not zero. Therefore, the mechanical angle positions are shifted in the circumferential direction so that the electrical angle phases of these two salient poles 5 are both zero.

As a result, as indicated by the broken line L5 in FIG. 10, the mechanical angle position of the salient pole No. 5 coincides with the rotor electrical angle phase, and as indicated by the broken line L7 in FIG. The angular position matches the rotor electrical angular phase. The mechanical angle positions of these salient poles 5 (No. 5 and No. 7) are the same as the mechanical angle positions of the salient poles when it is assumed that 28 salient poles are provided that are four times the shaft angle multiplier x. Become. In other words, this setting method can be said to be a setting method in which 12 salient poles are selected from 28 salient poles and 16 are thinned out. The mechanical angle positions of the other salient poles 5 with phase numbers 2 to 4 may be determined in a similar manner.

Even in such a different interval resolver 1', the number of salient poles 5 around which the coil 4 is wound can be reduced to less than four times the shaft angle multiplier (that is, the number of salient poles 5 can be thinned out). ' can be miniaturized and the configuration can be simplified. Also, since an increase in the rotor diameter can be prevented, a decrease in controllability due to an increase in inertia can be suppressed. In FIG. 10, the resolver 1' having the shaft angle multiple x of 7 and the number of salient poles s of 12 was illustrated, but similar to the above-described embodiment, it can also be applied to other resolvers having the shaft angle multiple x and the number of salient poles s. It is possible. Moreover, the above method of setting the number of turns of the coil 4 by multiplying the number of turns coefficient K can also be applied to a different spacing resolver. By applying the same configuration as the embodiment described above, the same effects as those described above can be obtained.

[4. others]
The shape and configuration of each element (the salient pole portion 21 of the rotor 2 and the salient pole 5 of the stator 3) of the resolvers 1 and 1' described above are not limited to those described above. For example, the rotor 2 may not have a laminated structure, and the shape of the salient poles 5 may not be T-shaped. Moreover, the circuit configuration described above is also an example, and a circuit other than the configuration described above may be provided.

The resolver described above is of the inner rotor type (a structure in which the stator is arranged opposite to the radially outer side of the rotor). configuration may be applied. Moreover, the above-described configuration may be applied to a resolver in which the stator is arranged to face the rotor in the axial direction (so-called axial gap structure) instead of the resolver in which the stator is arranged to face the rotor in the radial direction. That is, the rotor is provided with the same number of salient poles as the shaft angle multiplier, and the stator is provided with salient poles in the number of multiples of 4. Each salient pole has a first phase coil, a second phase coil, and a third phase coil. , fourth-phase coils may be wound in the same number, and the resolver may have an axial gap structure. Even with such a configuration, by setting the number of salient poles to less than four times the shaft angle multiplier of the rotor, the same effects as those of the above-described embodiment can be obtained.

1, 1a to 1k Resolver 1' Different spacing resolver (resolver)
2 rotor 3 stator 4 coil 4A first-phase coil 4B second-phase coil 4C third-phase coil 4D fourth-phase coil 5 salient pole 9 shaft 10 motor 11 motor stator 12 motor rotor 13 housing 21 salient pole portion C rotation center K winding coefficient n natural number s number of salient poles (number of salient poles)
x-axis double angle

Claims (5)

A resolver comprising a rotor fixed to a shaft and a stator facing the rotor,
The rotor has the same number of salient pole portions as the shaft angle multiplier of the resolver,
The stator has salient poles that are multiples of 4 and are radially protruding from an annular core and arranged at predetermined intervals in the circumferential direction, and coils wound around each of the salient poles,
As the coils, the same number of first-phase coils with an electrical angle of 0 degrees, second-phase coils with an electrical angle of 90 degrees, third-phase coils with an electrical angle of 180 degrees, and fourth-phase coils with an electrical angle of 270 degrees. have
the number of salient poles is less than the value obtained by multiplying the shaft angle by 4 and is 12 or more;
The relationship between the shaft angle multiplier and the number of salient poles is obtained by dividing the mechanical angle of 360 degrees by the number of salient poles, and the mechanical angle between the salient poles is the electrical angle of the rotor, 60 degrees, multiplied by a natural number. is set except for
A figure formed by connecting the in-phase coils adjacent in the circumferential direction with a straight line is not point-symmetrical with respect to the rotation center of the shaft, and when the stator is bisected by an arbitrary diameter, both areas are necessarily formed. , each number of turns of the in-phase coil is set using a predetermined turns factor
A resolver characterized by : The salient poles are arranged at equal intervals in the circumferential direction,
The shaft angle multiplier is 7, the number of salient poles is 12,
2. The relationship between the shaft angle multiplier and the number of salient poles is set so that all combinations of electrical angle phase shift amounts of the phase coils with respect to the salient pole portions are the same. Described resolver . A resolver comprising a rotor fixed to a shaft and a stator facing the rotor,
The rotor has the same number of salient pole portions as the shaft angle multiplier of the resolver,
The stator has salient poles that are multiples of 4 and are radially protruding from an annular core and arranged at predetermined intervals in the circumferential direction, and coils wound around each of the salient poles,
As the coils, the same number of first-phase coils with an electrical angle of 0 degrees, second-phase coils with an electrical angle of 90 degrees, third-phase coils with an electrical angle of 180 degrees, and fourth-phase coils with an electrical angle of 270 degrees. have
the number of salient poles is less than a value obtained by multiplying the shaft angle multiple by four;
The salient poles are arranged at different intervals in the circumferential direction,
The relationship between the shaft angle multiplier and the number of salient poles is obtained by dividing the mechanical angle of 360 degrees by the number of salient poles, and the mechanical angle between the salient poles is the electrical angle of the rotor, 60 degrees, multiplied by a natural number. is set except for
A resolver characterized by: The number of salient poles is 12 or more,
A figure formed by connecting the in-phase coils adjacent in the circumferential direction with a straight line is not point-symmetrical with respect to the rotation center of the shaft, and when the stator is bisected by an arbitrary diameter, both areas are necessarily formed. 4. The resolver according to claim 3 , wherein the number of turns of each of said in-phase coils is set using a predetermined turns factor. a resolver according to any one of claims 1 to 4 ;
a motor rotor that rotates integrally with the shaft;
A motor stator fixed to the housing.

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