JPH0756455B2 - Magnetic resolver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to an improvement of a magnetic resolver in which two stator plates are stacked to form a stator.

<Prior Art> Such a magnetic resolver has been disclosed in the application specification of Japanese Patent Application No. Sho 63-30988 filed by the present applicant.

This magnetic resolver uses two stator plates each having a plurality of salient poles with teeth formed at a constant pitch p at the tip, and these stator plates have a tooth phase of p / 4 between adjacent salient poles. The stator is constructed by shifting and stacking.

In the stator configured as described above, the coil wound around the salient pole of one of the stator plates is excited by a voltage signal of Ecos ωt (E is the amplitude of voltage, ω is angular velocity, t is time) (hereinafter, this coil is referred to as sin Phase coil), the coil wound around the salient pole of the other stator plate is excited by a voltage signal of Esinωt (hereinafter, this coil is referred to as a cos phase coil), and is generated at both ends of each coil by excitation. Rotation is detected based on the voltage.

In such a magnetic resolver, the mechanical error generated in the phase difference p / 4 between the teeth of the two stator plates is caused by the excitation signals Esinωt and Esinωt.
It was removed by adjusting the electrical angle of cosωt.

<Problems to be Solved by the Invention> In a magnetic resolver, if there is an error in the circularity of the stator or the rotor, the gap between the rotor and the stator varies due to the rotation of the rotor. As a result, higher-order ripples occur in the detection signal of the magnetic resolver and the detection accuracy deteriorates.

The magnetic resolver described above cannot correct such an error in roundness.

The present invention has been made to solve such a problem, and an object of the present invention is to realize a magnetic resolver that can effectively reduce an error in circularity generated between a rotor and a stator.

<Means for Solving the Problems> The present invention is a magnetic resolver configured as follows.

(1) 4n salient poles with teeth formed at the pitch p (n
Is provided as an integer) and the phase of the teeth of each salient pole is shifted by p / 4 according to the arrangement order of the salient poles, and is 0 ° according to the arrangement order.
A salient pole, a 90 ° salient pole, a 180 ° salient pole, and a 270 ° salient pole, and two stator plates sandwiching a non-magnetic member, one stator plate with a 0 ° salient pole and the other. The stator formed by superposing 90 ° salient poles of the stator plate, the coil wound on each salient pole, and the coil wound on one of the stator plates have a voltage of Esinωt (E is the amplitude of voltage, ω is Excitation at angular velocity, t is time,
The coil wound around the salient pole of the other stator plate is a signal source that is excited by a voltage of Ecosωt, and the coils wound around the adjacent 0 ° salient pole and 90 ° salient pole are connected in series. A pair of coils, The 0 ° phase coil in which the pairs at the positions separated by the mechanical angle are connected in series, and the serially connected ones are connected in parallel, and the adjacent 180 ° salient pole and 270 ° salient pole are wound. The coils are connected in series, and with this pair of coils connected in series, A 180 ° phase coil in which the pairs at the positions separated by the mechanical angle are connected in series, and the serially connected pairs are connected in parallel, and the 0 ° phase coil and the 180 ° phase of the one stator plate are connected. Calculation of calculating the voltage difference between both ends of the coil and the voltage difference between the 0 ° phase coil and the 180 ° phase coil of the other stator plate, and adding the difference between these two to detect the rotation detection signal of the rotor. A magnetic resolver comprising a circuit.

(2) In the 0 ° phase coil, the coils wound around the adjacent 0 ° salient poles and 90 ° salient poles are connected in series, and a pair of coils connected in series, The pair of mechanical angles are connected in series, and those connected in series in this way are connected in series, and the 180 ° phase coil is an adjacent 180 ° salient pole and 270 °. Connect the coils wound on the salient poles in series, and with this pair of coils connected in series, 2. The magnetic resolver according to claim 1, wherein the pairs at positions separated by a mechanical angle are connected in series, and the serially connected pairs are connected in series.

<Operation> In the present invention as described above, the salient pole wound with the coil of sin phase and the salient pole wound with the coil of cos phase are 360 ° / (number of salient poles)
By superimposing them by shifting the mechanical angles only, the error component generated in the inductance of the coil due to the error of the circularity is effectively removed.

<Example> Hereinafter, the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram of an embodiment of the present invention, in which (a) is a plan view and (b) is a sectional view taken along line XX in FIG.

In the figure, reference numeral 1 is a rotor having a cylindrical shape and teeth 2 formed on the inner circumference at a constant pitch p.

Reference numeral 3 denotes a stator arranged inside the rotor 1, which is formed by stacking two stator plates 31 and 32 having the same shape with a non-magnetic member 33 interposed therebetween.

Each stator plate 31 and 32, 4n (n is an integer), for example, 16 salient poles 311 _{1-311 16} 321 ₁ to 321 _16. Teeth 4 having a pitch p facing the teeth 2 are formed at the tips of these salient poles. In the figure, although not shown only by salient 311 _{1-311 16,} stator teeth 321 _{1-321 16} are arranged superimposed on the lower stator plate 31. The phases of the teeth formed on the salient poles are shifted by p / 4 according to the arrangement order of the salient poles. For example, with respect to the salient poles 311 ₁ tooth, the salient pole 311 _2, 311 _3, 311 ₄ teeth phase is shifted respectively by p / 4,2p / 4,3p / 4.

The salient poles 311 ₁ , 311 ₂ , 311 ₃ and 311 ₄ are a 0 ° salient pole, a 90 ° salient pole, a 180 ° salient pole and a 270 ° salient pole, respectively. Hereinafter, 0 ° salient poles, 90 ° salient poles, 180 ° salient poles, and 270 ° salient poles are repeated according to the arrangement order of salient poles.

The phase of the salient poles of the stator plate 32 is similar to that of the stator plate 31.

The salient poles 311 _{1 to} 311 ₁₆ and 321 _{1 to} 32 _{16 16} each have a coil 31
2 ₁ -3 12 ₁₆ and 322 ₁ 322 ₁₆ are wound.

41 is a signal source for exciting the coils 312 _{1 to} 312 ₁₆ with a voltage signal of Ecos ωt (E is voltage amplitude, ω is angular velocity, t is time), and 42 is a coil 322 _{1 to} 322 ₁₆ with a voltage signal of Esin ωt. It is a signal source. Thus, the coil 312 _{1-312 16}
The coil of the sin phase, the coil 322 _{1-322 16} becomes coils cos phase.

Reference numeral 5 is an arithmetic circuit for calculating the rotation of the rotor 1 based on the voltage across the coil.

Here, how to connect the coils will be described.

FIG. 2 is an explanatory view showing a coil wound around two stator plates.

In the stator plate 31, as shown in FIG. 3A, coils wound around adjacent salient poles are connected in series to form coils L _{1 to} L ₈ .

Further, the coils L _{1 to} L ₈ are connected as shown in FIG. 3 to form a 0 ° phase coil Ls _0, and are connected as shown in FIG. 4 to form a 180 ° phase coil Ls ₁ . .

On the other hand, also in the stator plate 32, adjacent coils are connected in series to form coils L _{1 to} L ₈ as shown in FIG.

Furthermore, the coils L _{1 to} L ₈ are connected as shown in FIG. 3 to form a 0 ° phase coil Lc _0, and are connected as shown in FIG. 4 to form a 180 ° phase coil Lc ₁ . .

It should be noted that, in FIGS. 3 and 4, coil pairs located at positions separated by a mechanical angle of 180 °, such as coils L ₁ and L ₅ and L ₂ and L ₆ , are connected, but in general, Is Connect in series the coil pairs that are separated by the mechanical angle of.

Also, the 0 ° phase coil and the 180 ° phase coil are configured by connecting the serially connected elements in parallel as described above.
The 0 ° phase coil and the 180 ° phase coil may be configured by connecting those connected in series in series. For example, coil L ₁
A 0 ° phase coil may be configured by connecting in series with L ₅ and L ₅ and connecting in series with coils L ₃ and L ₇ in series.

The stator plates 31 and 32 have centers O ₁ and O ₂ , and a line X ₁ −X ₁ passing through the center.
And X ₂ −X ₂ are overlapped. by this,
Corresponding coils are superposed between the stator plates 31 and 32 by shifting the mechanical angle of 22.5 °.

FIG. 5 shows a configuration example of the arithmetic circuit 5 that calculates the rotation detection signal based on the voltage across the coils connected in this manner.

In the magnetic resolver configured as described above, the roundness error generated in the rotor and the stator is removed as follows.

When the stator or the rotor has an error of circularity, the inductance L of the coil wound around each salient pole changes as follows when the rotor 1 rotates by θ.

L = L ₀ {1 + Δ ₁ sin (θ + ₁ )) + Δ ₂ sin (2θ + ₂ ) ... + msin (Nθ)} L ₀ : Inductance, ₁ , ₂ : Phase difference, m: Constant, Δ ₁ , Δ ₂ : Variation Amplitude, N: Number of teeth on rotor Here, θ is a rotation angle with one pitch of rotor teeth being 360 °.

In the formula, the value of the inductance is assumed to have a linear relationship with the gap between the rotor and the stator. With this formula,
Δ ₁ sin (θ + ₁ ) + Δ ₂ sin (2θ + ₂ ) ... Is an error caused by the gap between the rotor and the stator varying with the rotation of the rotor due to an error in circularity.
Further, msin (Nθ) which is phase-modulated by the rotation angle θ is a signal component.

Here, θ is 0 ° at the position indicated by X ₁ and X ₂ in the upper part of FIG.

In the stator plate 31 on which the sin-phase coil is wound, the average inductance of each of the coils L _{1 to} L ₈ when the rotor rotates by θ is given by the following equation, where Δ is the fluctuation rate.

L ₁ = L ₀ (1 + Δsink θ) L ₃ = L ₀ {1 + Δsink (θ + 90 °)} L ₅ = L ₀ {1 + Δsink (θ + 180 °)} L ₇ = L ₀ {1 + Δsink (θ−90 °)} L ₂ = L ₀ {1 + Δsink (θ + 45 °)} L ₄ = L ₀ {1 + Δsink (θ + 45 ° + 90 °)} L ₆ = L ₀ {1 + Δsink (θ + 45 ° + 180 °)} L ₈ = L ₀ {1 + Δsink (θ + 45 ° −90 °) } in these formulas, it was also used L ₁ ~L ₈ as an inductance of the coil L ₁ ~L _8.

Therefore, the inductance Ls ₀ of the 0 ° phase coil is given by the following equation.

On the other hand, the inductance Ls ₁ of the 180 ° phase coil is given by the following equation.

Where k = 1, L ₀ ° phase = L ₀ k = 2, L ₀ ° phase = L ₀ (1-Δ ² sin ² 2θ) k = 3, L ₀ ° phase = L ₀ k = At 4, L ₀ ° phase = L ₀ (1 + Δsin4θ) At k = 5, At L ₀ ° phase = L ₀ k = 6, At L ₀ ° phase = L ₀ (1-Δ ² sin ² 6 θ) At k = 7 , L ₀ ° phase = L ₀ k = 8, L ₀ ° phase = L ₀ (1 + Δsin8θ).

In these equations, when k is an odd number, the variation is not included.

In the case of k = 2,6, ..., That is, in the case of k = {4 (l-1) +2}, (l
= 1,2 ...), the fluctuation appears as a quadratic term. here,
From 1> Δ >> Δ ² , the second-order fluctuation can be ignored because it is sufficiently small.

When k = 4,8 ..., That is, when k = 4l,
The fluctuation component becomes a first-order term. The present invention is characterized by reducing this item.

That is, when k = 4l, Ls ₀ = L ₀ {1 + Δsin (4lθ)}. Therefore, the 4th-order component appears as an error.

Similarly, in the formula, Ls ₁ = L ₀ {1 + Δsin (4lθ ′)} = L ₀ {1-Δsin (4lθ)}, and the 4l-order component becomes an error.

Considering the 4th-order error component and signal component, coils Ls ₀ , Ls
₁ voltage across Vs _0, Vs ₁ is as follows.

Vs ₀ = A {1 + Δsin (4lθ) + msin Nθ} cosωt Vs ₁ = A {1-Δsin (4lθ) -msin Nθ} cosωt The difference between these voltages taken by the amplifier 51 in FIG. 5 is as follows.

Vs ₀ −Vs ₁ = 2A {Δsin (4lθ) ＋ msin Nθ} cosωt For the coil wound around the stator plate 32, the stator plate 31
The coil Lc taken by the amplifier 52 as well as the coil wound on
The difference between the voltages Vc ₀ and Vc ₁ between ₀ and Lc ₁ is as follows.

Vc ₀ −Vc ₁ = 2A {Δsin4l (θ + 4) + mcos Nθ} sinωt In this equation, is the mechanical deviation between the sin phase coil and the cos phase coil.

The final output V _{SIG of the} magnetic resolver obtained by the adder 53 is as follows.

The first term on the right side of the equation becomes a signal component, and the second term on the right side becomes an error component. In order to reduce the error component, it is necessary to select so that the maximum value of sin ² (4lθ) + sin ² {4l (θ +)} is minimized. Focusing on 4l = 4, which has a large variation among 4l = 4,8,12 ... In this equation, the second term of the equation becomes 1 and the error becomes minimum when = 22.5 °. This angle corresponds to 360 ° / 16.

In general, the error component is minimized if = 360 ° / number of salient poles.

In the embodiment, the outer rotor type magnetic resolver is used, but the inner rotor type may be used.

<Effect> According to the present invention, it is possible to effectively remove the 4l-order error component that greatly affects the signal component due to the variation generated in the detection signal due to the error in the circularity of the rotor and the stator. As a result, the effect of roundness error is reduced, and a highly accurate detection signal can be obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention, FIGS. 2 to 4 are explanatory diagrams showing how to connect coils, and FIG. 5 is a diagram showing a specific configuration example of an arithmetic circuit. . 1 …… Rotor, 2,5 …… Tooth, 3 …… Stator, 31,32 ……
Stator plate, 311 _{1 to} 311 ₁₆ ,, 321 _{1 to} 321 ₁₆ ... salient pole, 312 ₁
~ 312 ₁₆ , 322 ₁ ~ 322 ₁₆ …… Coil, 41,42 …… Signal source, 5
…… Arithmetic circuit.

Claims (2)

[Claims] 1. A salient pole having teeth formed with a pitch p at the tip is 4n.
The number of teeth (n is an integer) is provided, and the phases of the teeth of each salient pole are shifted by p / 4 according to the arrangement order of the salient poles. , A 270 ° salient pole and two stator plates sandwiching a non-magnetic material member, and a 0 ° salient pole of one stator plate and a 90 ° salient pole of the other stator plate are superposed. The configured stator, the coil wound on each salient pole, and the coil wound on one stator plate are excited by a voltage of Esinωt (E is voltage amplitude, ω is angular velocity, t is time),
The coil wound around the salient pole of the other stator plate is a signal source that is excited by a voltage of Ecosωt, and the coils wound around the adjacent 0 ° salient pole and 90 ° salient pole are connected in series. A pair of coils, The 0 ° phase coil in which the pairs at the positions separated by the mechanical angle are connected in series, and the serially connected ones are connected in parallel, and the adjacent 180 ° salient pole and 270 ° salient pole are wound. The coils are connected in series, and with this pair of coils connected in series, A 180 ° phase coil in which the pairs located at positions separated by mechanical angles are connected in series, and the serially connected pairs are connected in parallel, and the 0 ° phase coil and the 180 ° phase of the one stator plate are connected. Calculation of calculating the voltage difference between both ends of the coil and the voltage difference between the 0 ° phase coil and the 180 ° phase coil of the other stator plate, and adding the difference between these two to detect the rotation detection signal of the rotor. A magnetic resolver comprising a circuit. 2. The 0 ° phase coil has 90 ° salient poles and 90 ° adjacent poles.
° Connect the coils wound on the salient poles in series, and with this pair of coils connected in series, The pair of mechanical angles are connected in series, and those connected in series in this way are connected in series, and the 180 ° phase coil is an adjacent 180 ° salient pole and 270 °. Connect the coils wound on the salient poles in series, and with this pair of coils connected in series, 2. The magnetic resolver according to claim 1, wherein the pairs at positions separated by a mechanical angle are connected in series, and the serially connected pairs are connected in series.