JP2556383B2 - Magnetic resolver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to improvement in detection accuracy of an eccentric type magnetic resolver.

<Prior Art> A magnetic resolver is an eccentric type magnetic resolver that detects the rotation by displacing the rotation center of the rotor with respect to the center of the stator and utilizing the fact that the gap between the rotor and the stator changes due to the rotation of the rotor. There is.

An example of such an eccentric type magnetic resolver is described in the specification of Japanese Patent Application No. 63-205971 filed by the present applicant.

The eccentric magnetic resolver detects the absolute rotational position by making the rotation center of the rotor eccentric with respect to the center of the stator and changing the gap between the rotor and the stator by one cycle by one rotation of the rotor. Gap detection is
Winding is applied to the stator or rotor and detected electrically.

<Problems to be Solved by the Invention> However, in the eccentric type magnetic resolver, the gap between the rotor and the stator is determined by the load applied to the magnetic resolver, the processing error, and the coaxiality between the rotor and the stator due to thermal deformation of the magnetic resolver. Since it is very sensitive to the factors that give an error, there was a problem in practical use.

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 obtain high detection accuracy even if an error factor of coaxiality occurs.

<Means for Solving the Problems> The present invention is provided with 4n (n is an integer) salient poles, and a 0 ° salient pole and a 90 ° salient pole are provided for each cluster of n salient poles. 180
Two stator cores with salient poles and 270 salient poles
The two stator cores have a 0 ° salient pole and 180
∘ salient poles, 90 ° salient poles and 270 ° salient poles are stacked one on top of the other, and two rotor cores facing the two stator cores, respectively. The center of rotation of the rotor core deviates from the center of the stator by a certain amount, and the center of rotation of the other rotor core deviates from the center of the stator by 180 ° in a direction 180 ° different from the direction in which the one rotor core deviates. Rotor and the first phase coil in which the coils wound around the 0 ° salient poles of the two stator cores are connected in series, and the 90
2nd phase coil in which coils wound on salient poles are connected in series,
A third phase coil in which coils wound around 180 ° salient poles of two stator cores are connected in series and two stator cores of 270
A four-phase coil consisting of a fourth-phase coil in which coils wound on salient poles are connected in series, and a sinusoidal excitation signal is applied to the first-phase coil and the third-phase coil, and the second-phase coil and the fourth-phase coil are connected to each other. A signal source that gives a cosine wave excitation signal to the phase coil, and a voltage generated in the coil to which a sine wave excitation signal is given,
A magnetic resolver comprising: an arithmetic circuit that calculates a rotation detection signal of a phase modulation type rotor based on a voltage generated in a coil to which a cosine wave excitation signal is applied.

<Operation> In the present invention as described above, two rotor cores are provided, and the rotor cores are eccentric by the same amount in directions different from each other by 180 ° with respect to the center of the stator, and by utilizing this eccentricity, the coaxial error between the rotor and the stator is electrically reduced. To remove it.

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

1A and 1B are configuration diagrams of an embodiment of a magnetic resolver according to the present invention, in which FIG. 1A is a plan view and FIG.
It is sectional drawing of Z part.

 In the figure, 10 is a stator and 20 is a rotor.

In the stator 10, 11 is an annular stator ring, 12,1
Reference numeral 3 is a stator core fixed to the stator ring 11. The stator core 12 is formed with 4n (n is an integer), for example, 24 salient poles at a constant pitch. Six salient poles are formed, each of which is a 0 ° salient pole 121 _{1 to} 121 ₆ , 90 ° salient pole 122 _1.
- 122 _6, is divided into 180 ° salient 123 _{1-123 6,} 270 ° salient 124 _{1-124 6.}

Coils wound into 6 pieces divided 125 _{1 to} 125 ₆ , 126 ₁ to 1
26 ₆ , 127 _{1 to} 127 ₆ , 128 _{1 to} 128 ₆ are connected in series.

The stator core 13 also has the same shape as the stator core 12. The salient poles of the stator cores 12 and 13 are overlapped with each other in the same phase. In this case, 0 ° salient pole and 180
゜ Salient poles, 90 ° salient poles and 270 ° salient poles are superposed. Although not shown, the coils 135 _{1 to} 135 ₆ , 136 _{1 to} 136 ₆ , 137 _{1 to} 137 ₆ are provided on the 0 ° salient pole, 90 ° salient pole, 180 ° salient pole, and 270 ° salient pole of the stator core 13, respectively. 138 _{1-138 6} is wound.

In the rotor 20, 21 is an annular rotor ring, and 22 and 23 are rotor cores fixed to the rotor ring 21. The center O of the rotor ring 21 coincides with the center of the stator ring 11. The center O _{1 of the} rotor core 22 is eccentric from the center O by Δg. The center O _{2 of the} rotor core 23 is eccentric by Δg in a direction different from the center O ₁ by 180 ° with respect to the center O.

Due to such eccentricity, the gap between the salient pole tips of the stator cores 12 and 13 and the inner peripheral surface of the rotor core is 1
When it rotates, it changes in a sine wave for one cycle. This change in the sine wave state is 180 ° out of phase between the rotor cores 22 and 23.

In this magnetic resolver, teeth are not formed on the rotor and salient poles.

Reference numeral 30 is a signal source that drives a coil wound around each salient pole with an AC signal, and 40 is a calculation unit that detects the rotation of the rotor based on the current flowing through each coil.

 A specific configuration of the signal source 30 is shown in FIG.

 In the figure, each coil is as follows.

L ₀ : Coil in which coils wound on 0 ° salient pole of stator core 12 are connected in series L ₀ ′: Coil in which coils wound on 0 ° salient pole of stator core 13 are connected in series L ₉₀ : ₉₀ ° salient of stator core 12 Coil in which coils wound around poles are connected in series L ₉₀ ′: Coil in which coils wound around 90 ° salient poles of stator core 13 are connected in series L ₁₈₀ : Coil wound around 180 ° salient poles of stator core 12 are connected in series Coil L ₁₈₀ ′: A coil in which coils wound around 180 ° salient poles of stator core 13 are connected in series L ₂₇₀ : A coil in which coils wound around 270 ° salient poles of stator core 12 are connected in series L ₂₇₀ ′: Stator core 13 Coils in which coils wound on 270 ° salient poles are connected in series. As shown in the figure, in stator cores 12 and 13, coils wound on 0 ° salient poles, coils wound on 90 ° salient poles, 180 ° Coils wound on salient poles, 270 ° salient poles Each other wound coils are connected in series, respectively. 18 coils connected in series, wound on a 0 ° salient pole
A coil wound around a 0 ° salient pole is excited by a signal source 31 with an AC voltage Esinωt (E: amplitude of voltage, ω: angular velocity, t: time). Further, the coil wound on the 90 ° salient pole and the coil wound on the 270 ° salient pole are excited by the signal source 32 at a voltage of Ecosωt.

Voltages V _{1 to} V ₄ are generated in the _four resistors R from the current flowing due to the coil excitation.

 FIG. 3 is a diagram showing a specific configuration of the arithmetic unit 40.

 In the figure, each coil is as follows.

L _1: the coil L ₀ and L ₀ 'the coil L ₂ connected in series: the coil L ₉₀ and L _90' of coil L ₃ connected in series: a coil L ₄ of the coil L ₁₈₀ and L ₁₈₀ 'are connected in series: a coil L Coil in which ₂₇₀ and L ₂₇₀ ′ are connected in series In such a circuit, the phase modulation signal V is obtained by the calculation of the following equation.

V = V ₁ −V ₃ + V ₂ −V ₄ C is a phase difference counter that clocks the phase difference between the phase modulation signal V and the excitation signal Esinωt whose phase is not modulated.
Count with CLK.

 The operation of the magnetic resolver thus configured will be described.

When there is no coaxial error between the center of the stator and the center of the rotor, that is, when the center of the stator ring and the center of the rotor ring are at the point O, the gap between the stator core and the rotor core is given by the following equation.

_{g 1 = g 0 + Δgsinθ =} g 1 'g 2 = g 0 + Δgsin (θ + 90 _{°) = g 2' g 3 =} g 0 + Δgsin (θ + 180 _{°) = g 3 'g 4 =} g 0 + Δgsin (θ + 270 °) = g ₄ ′ θ: Rotational angle of rotor where g ₁ , g ₂ , g ₃ and g ₄ are the rotor core and 0 ° salient pole, 90 ° salient pole, 180 ° salient pole, 270 ° salient pole and rotor core, respectively. Is the gap. g ₁ ′, g ₂ ′, g ₃ ′, g ₄ ′ are 0 ° salient poles, 90 ° salient poles, 180 ° salient poles and 270 salient poles of stator core 13, respectively.
° Gap between salient pole and rotor core.

In general, there is a coaxial error at the center O _R of the center O _S and rotor ring 21 of the stator ring 11 as shown in Figure 4. Of the coaxial error, the component in the O ₁ -O ₂ direction of Fig. ₁ is α, O ₁ -O ₂
When the component in the direction orthogonal to the direction is β, the gap between the stator core and the rotor core is as follows.

g ₁ = g ₀ + Δgsin θ + α g ₁ ′ = g ₀ + Δgsin θ −α g ₂ = g ₀ + Δgsin (θ + 90 °) + β g ₂ ′ = g ₀ + Δgsin (θ −90 °) −β g ₃ = g ₀ + Δgsin (θ + 180 ° ) -Α g ₃ ′ = g ₀ + Δgsin (θ + 180 °) + α g ₄ = g ₀ + Δgsin (θ + 270 °) -β g ₄ ′ = g ₀ + Δgsin (θ + 270 °) + β At this time, the coil inductance is as follows. Become.

L ₀ = L _A (1 + msin θ) + L _α L ₀ ′ = L _A (1 + msin θ) −L _α L ₉₀ = L _A {1 + msin (θ + 90 °)} + L _β L ₉₀ ′ = L _A {1 + msin (θ + 90 °)} − L _β L ₁₈₀ = L _A {1 + msin (θ + 180 °)}-L _α L ₁₈₀ ′ = L _A {1 + msin (θ + 180 °)} + L _α L ₂₇₀ = L _A {1 + msin (θ + 270 °)} − L _β L ₂₇₀ ′ = L _A {1 + msin (θ + 270 °)} + L _β L _A : Constant L _α : Inductance change due to coaxial error α L _β : Inductance change due to coaxial error β where coils L ₀ and L ₀ ′, L ₉₀ and L ₉₀ ′, L ₁₈₀ and L ₁₈₀ ′, L
_{Since 270} and L ₂₇₀ ′ are connected in series, 4-phase coil L ₁
The inductance of ~ L ₄ is given by the following equation.

L ₁ = L ₀ + L ₀ ′ = 2L _A (1 + msinθ) L ₂ ＝ L ₉₀ ＋ L ₉₀ ′ ＝ 2L _A (1 + msin (θ + 90 °)} ＝ 2L _A (1 + mcos θ) L ₃ ＝ L ₁₈₀ ＋ L ₁₈₀ ′ ＝ 2L _A { 1 + msin (θ + 180 °)} = 2L _A (1-msinθ) L ₄ = L ₂₇₀ + L ₂₇₀ ′ = 2L _A {1 + msin (θ + 270 °)} = 2L _A (1-mcos θ) Due to this, inductance due to coaxial error α and β The effects of L _α and L _β are eliminated.

By the signal source 30, the first phase coil L ₁ and the third phase coil L ₃ are excited by the excitation signal Esinωt, and the second phase coil L ₂ and the fourth phase coil L ₄ are driven by the excitation signal Ecosωt. voltage V ₁ ~V ₄ caused a resistor connected to each phase of the coil L ₁ ~L ₄
Is as follows:

_{V 1 = K (1 + msinθ} ) sinωt V 2 = K (1 + mcosθ) cosωt V 3 = K (1-msinθ) sinωt V 4 = K (1-mcosθ) cosωt K: constant computing unit 40 is computed for these voltages follows I do.

(V ₁ −V ₃ ) + (V ₂ −V ₄ ) = 2mKsinθsinωt + 2mKcosθcosωt = 2mKsin (ωt−θ + 90 °) The phase of the signal given by the formula is one rotation of the rotor.
Since it is modulated by 360 °, the absolute angle during one rotation can be detected by measuring the phase difference with the excitation signal Esinωt which is not phase modulated by the phase difference counter C in FIG. The rotation speed can be detected by measuring the phase change speed.

Although the example of the outer rotor type magnetic resolver is shown in the embodiment, the magnetic resolver may be an inner rotor type.

<Effect> According to the present invention, the following effects can be obtained.

When only one stator core is provided, the detection signal has a value obtained from the inductance of the following equation.

_{L 0 -L 180 + L 90 -L} 270 = L A (1 + msinθ) + L α - [L A {1 + msin (θ + 180 _{°)} - L α] + L} A {1 + msin (θ + 90 _{°)} + L β - [L} A {1 + msin (theta + 270 _{°)} - L β] = 2L} a m (sinθ + cosθ) +2 (L α + L β) coaxial error alpha as shown in the above equation, the effect of beta inductance L _alpha, would be included as L _beta.

On the other hand, the magnetic resolver according to the present invention provided with two stator cores has different eccentric directions of 180 °.
Since the coils of the one stator core were connected in series, the detection signal has a value obtained from the inductance of the following equation.

_{(L 0 + L 0 ')} - (L 180 + L 180') + (L 90 + L 90 ') - (L 270 + L 270') = 2L A m (sinθ + cosθ) coaxial error α as shown in this equation, the β The impact has been removed.

That is, in the magnetic resolver according to the present invention, the influence of the coaxial deviation between the rotor and the stator can be removed by taking the sum of the signals obtained from the two cores that are eccentric in directions different by 180 °. As a result, the error in the detection signal can be reduced even if an error factor of the coaxiality such as a load applied to the magnetic resolver or thermal deformation occurs.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of a magnetic resolver according to the present invention, and FIGS. 2 and 3 are diagrams showing a specific configuration of a signal source and a calculation unit of the magnetic resolver of FIG. 1, and FIG. FIG. 3 is an operation explanatory view of the magnetic resolver of FIG. 1. 10 …… Rotor, 12,13 …… Stator core, 121 _{1 to} 121 ₆ , 12
2 ₁ ~ 122 ₆ , 123 ₁ 123 ₆ , 124 ₁ ~ 124 ₆ ...... salient pole, 125 ₁ ~ 125 ₆ , 1
26 ₁ ~ 126 ₆ , 127 ₁ ~ 127 ₆ , 128 ₁ ~ 128 ₆ ...... Coil, 20 ......
Rotor, 22,23 …… Rotor core, 30 …… Signal source, 40 ……
Arithmetic unit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A 64-43718 (JP, A) JP-A 1-276017 (JP, A) JP-A 1-282419 (JP, A) JP-A 1- 284712 (JP, A) JP-A-3-57915 (JP, A)

Claims (1)

(57) [Claims] 1. 4n (n is an integer) salient poles are provided, and each salient of n salient poles is a 0 ° salient pole and a 90 salient pole, respectively.
It has two stator cores that form a salient pole of 180 °, a salient pole of 180 ° and a salient pole of 270 °. These two stator cores have a salient pole of 0 ° and a salient pole of 180 °, a salient pole of 90 ° and a salient pole of 270 °. A stator in which poles are stacked one on top of the other and two rotor cores, which are arranged to face the two stator cores, respectively, are stacked, and the rotation center of one rotor core is deviated from the center of the stator by a certain amount. hand,
The center of rotation of the other rotor core is offset from the center of the stator by the same amount as the one rotor core in a direction 180 ° different from the direction in which the one rotor core is displaced, and the 0 ° salient pole of the two stator cores. First-phase coil in which wound coils are connected in series, second-phase coil in which coils wound around 90 ° salient poles of two stator cores are connected in series, 2
A four-phase coil consisting of a third-phase coil in which coils wound on 180 ° salient poles of one stator core are connected in series and a fourth-phase coil in which coils wound on 270 ° salient poles of two stator cores are connected in series , A signal source that gives a sine wave excitation signal to the first phase coil and the third phase coil, and a cosine wave excitation signal to the second phase coil and the fourth phase coil, and a sine wave excitation signal A magnetic resolver comprising: an arithmetic circuit that calculates a rotation detection signal of a phase modulation type rotor based on a voltage generated in a coil and a voltage generated in the coil to which a cosine wave excitation signal is applied.