JP6861867B1 - Angle detection device and control device for rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an angle detection device capable of reducing an angle deviation due to an eddy current generated in a conductor arranged near a magnetic sensor without providing two conductors on both sides of the magnetic sensor, and a control device for a rotating electric machine provided with the angle detection device. To do.
SOLUTION: A plate-shaped member 8 having a conductive member 3 is provided so as to face a magnetic sensor 2, and an eddy current of the conductive member 3 is provided with respect to a magnitude of magnet magnetic flux density generated in the magnetic sensor 2 by a magnet 1. The arrangement prohibited area 7 in which the conductive member 3 is not arranged is provided on the plate-shaped member 8 so that the ratio of the magnitude of the eddy current magnetic flux density generated in the magnetic sensor 2 by the current is equal to or less than the preset upper limit ratio. An angle detection device provided.
[Selection diagram] Fig. 1

Description

The present application relates to an angle detection device and a control device for a rotary electric machine.

In the apparatus of Patent Document 1, by arranging the magnetic sensor between the non-magnetic first conductor and the non-magnetic second conductor, the magnetic field caused by the eddy current flowing in the first conductor on the magnetic sensor, And the magnetic fields exerted by the eddy currents in the second conductor on the magnetic sensor cancel each other out.

Japanese Unexamined Patent Publication No. 2013-104698

In the technique of Patent Document 1, the influence of the magnetic field of the eddy current is canceled by using two conductors, and it is necessary to arrange the conductors on both sides of the magnetic sensor. Therefore, it is difficult to reduce the size or weight of the angle detection device including the magnetic sensor.

Therefore, the present application applies to an angle detection device capable of reducing an angle deviation due to an eddy current generated in a conductor arranged near the magnetic sensor without providing two conductors on both sides of the magnetic sensor, and a control device for a rotating electric machine provided with the angle detection device. The purpose is to provide.

The first angle detection device according to the present application is
Magnets attached to the rotating body and
A magnetic sensor that is arranged to face the magnet and outputs a signal according to the magnetic field direction of the magnet.
A plate-shaped member having a conductive member, which is arranged so as to face the magnetic sensor, is provided.
The ratio of the magnitude of the eddy current magnetic flux density, which is the magnetic flux density generated in the magnetic sensor by the eddy current of the conductive member, to the magnitude of the magnet magnetic flux density, which is the magnetic flux density generated in the magnetic sensor by the magnet, is preset. The plate-shaped member is provided with an arrangement prohibited area in which the conductive member is not arranged so as to be equal to or less than the upper limit ratio.

The second angle detection device according to the present application is
Magnets attached to the rotating body and
A first magnetic sensor and a second magnetic sensor that face the magnet, are arranged at intervals in the axial direction of the rotating body, and output a signal corresponding to the magnetic field direction of the magnet.
A conductive member arranged between the first magnetic sensor and the second magnetic sensor,
It is equipped with an angle calculator that calculates the final angle information by averaging the angle information corresponding to the output signal of the first magnetic sensor and the angle information corresponding to the output signal of the second magnetic sensor. is there.

Further, the control device for the rotary electric machine according to the present application includes the above-mentioned first or second angle detection device, and controls the rotary electric machine based on the rotor angle of the rotary electric machine detected by the angle detection device. Is.

According to the first angle detection device and the control device of the rotary electric machine according to the present application, the eddy current magnetic flux density generated by the eddy current of the conductive member is large by providing the plate-shaped member with the arrangement prohibition region of the conductive member. Can be reduced. Since the ratio is not more than the upper limit ratio, the angle deviation due to the eddy current magnetic flux density can be suppressed to be less than a predetermined value. Therefore, the angular deviation due to the eddy current can be reduced without providing two conductors on both sides of the magnetic sensor.

According to the second angle detection device and the control device of the rotary electric machine according to the present application, the angle information of the first magnetic sensor and the second magnetism in which the phases of the angle information are shifted in opposite directions due to the eddy current of the conductive member. Since the angle information is calculated by averaging the angle information of the sensor, the phase shifts of the angles cancel each other out, and the angle shift due to the eddy current can be reduced. Therefore, the angular deviation due to the eddy current can be reduced without providing two conductors on both sides of the magnetic sensor.

It is a schematic block diagram of the angle detection apparatus which concerns on Embodiment 1. FIG. It is a projection drawing of the angle detection apparatus seen in the axial direction which concerns on Embodiment 1. FIG. FIG. 5 is a projection drawing of an angle detection device viewed in the axial direction for explaining the magnetic flux due to the eddy current according to the first embodiment. It is a projection drawing of the angle detection device seen in the axial direction for explaining the arrangement prohibition area which concerns on Embodiment 1. FIG. It is a figure for demonstrating the effective area which concerns on Embodiment 1. FIG. It is a figure for demonstrating the arrangement prohibition area which concerns on Embodiment 1. FIG. It is a figure for demonstrating the arrangement prohibition area which concerns on Embodiment 1. FIG. It is a figure for demonstrating the arrangement of the magnetic sensor which concerns on Embodiment 1. FIG. It is a schematic block diagram of the control device of the rotary electric machine provided with the angle detection device which concerns on Embodiment 1. FIG. It is a schematic block diagram of the control device of the rotary electric machine provided with the angle detection device which concerns on Embodiment 1. FIG. It is a schematic block diagram of the angle detection apparatus which concerns on Embodiment 2. FIG.

Hereinafter, embodiments of the angle detection device of the present application will be described with reference to the drawings. In each figure, the same or corresponding members and parts will be described with the same reference numerals.

Embodiment 1.
FIG. 1 is a diagram showing an overall configuration of the angle detection device according to the first embodiment. Note that FIG. 1 is a view of a main part of the angle detection device in the radial direction of the rotation axis C. FIG. 2 is a projection drawing of the angle detection device viewed in a direction parallel to the rotation axis C (hereinafter, referred to as axial direction Z). The rotation axis C is a virtual rotation center line of the rotating body 4. The axial direction Z is orthogonal to the X-axis direction and the Y-axis direction, which will be described later.

A straight line passing through the center of the magnet 1 and the center of the magnetic sensor 2 is defined as a central straight line. The center of the magnet 1 is the center of the north and south poles, and the center of the magnetic sensor 2 is the center of the sensor element portion that detects the magnetic field. In the present embodiment, the magnet 1 and the magnetic sensor 2 are arranged on the rotation axis C. Therefore, the central straight line coincides with the rotation axis C.

<Magnet 1>
The magnet 1 is attached to the rotating body 4. The magnet 1 is a permanent magnet. In the present embodiment, the magnet 1 is arranged at the tip of the rotating shaft 4 as the rotating body 4. By arranging it at the tip of the rotating shaft 4, a magnetic field with less distortion can be obtained as compared with the case where it is fitted on the outer circumference of the rotating shaft 4, and the angle error can be reduced. However, the magnet 1 may be fitted on the outer circumference of the rotating shaft 4. The magnet 1 is arranged on the rotation axis C. The north and south poles of the magnet 1 are arranged symmetrically with respect to the rotation axis C. The radius of the radial outer end face of the N pole coincides with the radius of the radial outer end face of the S pole. The magnet 1 shall rotate in the direction of the arrows in FIGS. 1 and 2.

<Magnetic sensor 2>
The magnetic sensor 2 is arranged so as to face the magnet 1. The magnetic sensor 2 outputs a signal according to the magnetic field direction of the magnet 1. The magnetic sensor 2 is arranged on the rotation axis C. When the magnet 1 rotates due to the rotation of the rotating shaft 4, the magnetic field direction of the magnet 1 also rotates, and the output signal of the magnetic sensor 2 also changes. A magnetoresistive effect element, a Hall element, or the like is used for the magnetic sensor 2.

The magnetic sensor 2 detects the magnetic field of the magnet 1 interlinking with the XY plane in which the sensor element is arranged, and represents the magnitude of the magnetic field in the X direction and the sensor cosine signal Vcos and the sensor sine that represents the magnitude of the magnetic field in the Y direction. Outputs the signal Vsin. The sensor cosine signal Vcos is a cosine wave-shaped signal corresponding to the angle of the magnet 1, and the sensor cosine signal Vsin is a sinusoidal signal corresponding to the angle of the magnet 1. The XY plane of the magnetic sensor 2 is arranged so as to be orthogonal to the rotation axis C (axial direction Z). The XY plane is composed of an X-axis and a Y-axis orthogonal to each other, and the origins of the X-axis and the Y-axis are arranged on the rotation axis C.

<Angle calculator 6>
The angle calculator 6 calculates the angle of the magnet 1 based on the output signal of the magnetic sensor 2. The angle calculator 6 is composed of a digital arithmetic circuit such as an IC (Integrated Circuit). Alternatively, the angle calculator 6 may be incorporated in a control device such as a rotary electric machine provided with a CPU (Central Processing Unit) and a memory or the like. Further, the angle calculator 6 may be a concept that constitutes a part of the angle detection device, or may be a concept that is an external configuration of the angle detection device.

The angle calculator 6 A / D converts the sensor cosine signal Vcos and the sensor sine signal Vsin output from the magnetic sensor 2. Then, the angle calculator 6 calculates the angle θ based on the A / D conversion value Vcos_ad of the sensor cosine signal and the A / D conversion value Vsin_ad of the sensor sinusoidal signal. For example, the angle θ is calculated using the equation (1).

When the cosine signal has an offset Vcos_ofs and the sine signal has an offset Vsin_offs, the angle θ is calculated using the equation (2).

Further, if there is an error such as an amplitude deviation or a phase difference deviation between the cosine signal and the sine signal, it may be corrected by a known method.

The angle calculator 6 may be incorporated in the magnetic sensor 2.

<Plate-shaped member 8 having a conductive member 3>
The plate-shaped member 8 having the conductive member 3 is arranged so as to face the magnetic sensor 2. The plate-shaped member 8 is arranged on the side opposite to the magnet 1 with respect to the magnetic sensor 2. Therefore, the magnetic sensor 2 is arranged between the magnet 1 and the plate-shaped member 8. The conductive member 3 is a conductive member such as copper. The plate-shaped member 8 and the conductive member 3 are formed in a flat plate shape. The plate-shaped member 8 and the conductive member 3 are arranged on the rotation axis C. The plate-shaped member 8 and the conductive member 3 are orthogonal to the rotation axis C.

<Magnet magnetic flux density Bm>
The magnetic field of the magnet 1 interlinking with the magnetic sensor 2 can be represented as shown by the dotted line 10 in FIG. The magnetic field lines emitted from the north pole of the magnet 1 and the magnetic field lines returning to the south pole have a large component in the axial direction Z perpendicular to the XY plane in the vicinity of the magnet 1, but a large component parallel to the XY plane in the vicinity of the magnetic sensor 2. ..

A case where the S pole of the magnet 1 is oriented in the X-axis direction at time t = 0 will be described. The magnet magnetic flux density Bm, which is the magnetic flux density of the magnet 1 interlinking with the magnetic sensor 2, is given by the equation (3). The magnet magnetic flux density Bm is represented by a vector of the magnetic flux density in the X-axis direction and the magnetic flux density in the Y-axis direction.

Here, ω is the angular velocity of the magnet 1, and t is the time. cosωt and sinωt are fundamental waves of the magnetic flux density Bm of the magnet and are primary components of the rotation frequency. Bm_amp is the amplitude of the fundamental wave of the magnet magnetic flux density Bm, and is the magnitude of the magnet magnetic flux density. The magnitude Bm_amp of the magnet magnetic flux density is determined by the strength of the magnet 1 (magnetic flux density) and the positional relationship (distance, orientation, etc.) between the magnet 1 and the magnetic sensor 2.

<Eddy current magnetic flux density Be due to conductive member>
On the other hand, in the magnetic field generated by the magnet 1, there is a component that enters perpendicularly to the conductive member 3. Here, the equation is derived on the assumption that the conductive member 3 is provided on the entire plate-shaped member 8. As shown by the dotted line in FIG. 3, the XY coordinates of the point P on the circle having the radius r centered on the rotation axis C in the conductive member 3 are given by the equation (4). Here, θp is the angle of the point P with respect to the X axis.

At this time, the component of the magnetic flux density of the magnet 1 at the point P in the vertical direction (axial direction Z) can be expressed by the equation (5). The amplitude Bp_amp of the magnetic flux density is determined by the strength of the magnet 1 (magnetic flux density) and the positional relationship between the point P and the magnet 1 (distance, direction, etc.).

Since the magnet 1 is rotating, the electromotive force ep generated at the point P of the conductive member 3 is given by the equation (6).

Assuming that the resistance of the conductive member 3 is R, the eddy current ip generated by the electromotive force ep in the equation (6) is the equation (7).

The magnetic field generated by the eddy current ip at the point P of the conductive member 3 is as shown by the dotted line 30 in FIG. Since the magnitude of the magnetic flux density Bep_abs generated by the eddy current of the conductive member 3 interlinking with the magnetic sensor 2 is proportional to the eddy current ip of the equation (7), the eddy current magnetic flux coefficient KBep is multiplied by the equation (7). It is given by the equation (8). The eddy current magnetic flux coefficient KBep is determined by the positional relationship (distance, etc.) between the point P and the magnetic sensor 2.

When the magnitude of the magnetic flux density Bep_abs of the formula (8) is divided into an X-axis component and a Y-axis component, the magnetic flux density Bep interlinking with the magnetic sensor 2 generated by the eddy current at the point P of the conductive member 3 is expressed by the formula. It is given in (9).

As shown by the dotted line in FIG. 3, any point on the circumference obtained by rotating the point P can be expressed in the same manner. Therefore, the chain is attached to the magnetic sensor 2 generated by the eddy current generated on the circumference of the conductive member 3. The intersecting magnetic flux density Bec is given by the equation (10) when the equation (9) is integrated on the circumference.

The eddy currents in all regions of the conductive member 3 may be considered, but the regions where the eddy currents are small can be omitted. The region where the eddy current increases corresponds to the region where the magnetic flux of the magnet 1 entering perpendicular to the conductive member 3 increases, and corresponds to the radial positions of the north and south poles of the magnet 1. As shown by hatching in FIG. 4, the region where the eddy current becomes large is a ring plate-shaped region centered on the rotation axis C. The inner and outer diameters of the annular plate-shaped region where the eddy current increases become smaller as the conductive member 3 is arranged away from the magnet 1.

As shown in FIG. 5, the component of the magnetic flux density of the magnet 1 interlinking the plate-shaped member 8 in the axial direction Z changes according to the radial position (radius r) with respect to the rotation axis C. Here, consider an effective region in which the component of the magnetic flux density in the axial direction Z becomes large. In the effective region, the component in the axial direction Z (direction parallel to the central straight line) of the magnetic flux density of the magnet 1 interlinking with each part of the plate-shaped member 8 is 1/5 of the maximum value Bmax of the component in the axial direction Z of each part. It is set in the area that is more than doubled.

The radial position where the magnetic flux density in the axial direction Z becomes the maximum value is determined by the positional relationship between the magnet 1 and the plate-shaped member 8. FIG. 6 shows how the magnetic field of the magnet 1 interlinks with the plate-shaped member 8 in the upper row, and shows the effective region at that time in the lower row. When the plate-shaped member 8 is arranged near the magnet 1 (a), the axial Z component of the magnetic field line is maximized in the radial direction outside the radial outer end of the magnet 1. It becomes a position, and the effective region becomes an annular plate-shaped region centered on the rotation axis C. On the other hand, in the case of (b) in which the plate-shaped member 8 is arranged away from the magnet 1, the component of the magnetic field line in the axial direction Z is maximized by moving inward in the radial direction from (a), and the effective region is set. , It becomes a disk-shaped region centered on the rotation axis C.

Since miniaturization of products is required in many cases, it is desirable that the distance between the magnet 1 and the plate-shaped member 8 is as small as possible. In that case, as shown in FIG. 6A, the position where the eddy current is maximum, that is, the component of the magnetic field line of the magnet 1 in the axial direction Z is maximum is the radial position radially outside the magnet 1. The arrangement prohibition region 7 may be set on the outer side in the radial direction of the circle whose radius is the outer diameter of the magnet 1.

The eddy current magnetic flux density Be, which is the magnetic flux density interlinking with the magnetic sensor 2, generated by the eddy current in the effective region of the ring plate shape as shown by hatching in FIG. 4 was generated on the circumference of the equation (10). The magnetic flux density due to the eddy current is integrated in the radial direction, and is given by the same equation (11) as the equation (10). The eddy current magnetic flux density Be is represented by a vector of the magnetic flux density in the X-axis direction and the magnetic flux density in the Y-axis direction.

Here, ω is the angular velocity of the magnet 1, and t is the time. sinωt and cosωt are fundamental waves of the eddy current magnetic flux density Be and are primary components of the rotation frequency. Be_amp is the amplitude of the fundamental wave of the eddy current magnetic flux density Be, and is the magnitude of the eddy current magnetic flux density. The magnitude of the eddy current magnetic flux density Be_amp is determined by the strength of the magnet 1 (magnetic flux density), the positional relationship between the magnet 1 and the conductive member 3, and the positional relationship between the conductive member 3 and the magnetic sensor 2.

<Phase advance of sensor output due to eddy current magnetic flux density>
Since the total magnetic flux density Bs detected by the magnetic sensor 2 is the total of the magnet magnetic flux density Bm and the eddy current magnetic flux density Be, it is given by the equation (12).

Since the eddy current magnetic flux density Be is smaller than the magnet magnetic flux density Bm, the equation (13) holds between the magnitude Bm_amp of the magnet magnetic flux density and the magnitude Be_amp of the eddy current magnetic flux density. When the equation (13) is used, the equation obtained by substituting the equation (3) and the equation (11) into the equation (12) can be approximated as the equation (14).

From the equation (14), the total magnetic flux density Bs becomes a magnetic flux density whose phase is advanced by Be_amp / Bm_amp × ω with respect to the magnet magnetic flux density Bm of the equation (3) by adding the eddy current magnetic flux density Be. Become. Therefore, the sensor cosine signal Vcos and the sensor sinusoidal signal Vsin of the magnetic sensor 2 obtained by the components in the X-axis direction and the components in the Y-axis direction of the total magnetic flux density Bs are Be_amp with respect to the sensor signal obtained by the magnet magnetic flux density Bm. The phase advances by / Bm_amp × ω. Here, Be_amp is the magnitude of the eddy current magnetic flux density Be, Bm_amp is the magnitude of the magnet magnetic flux density Bm, and ω is the angular velocity of the magnet 1.

The sensor cosine signal Vcos and the sensor sinusoidal signal Vsin of the magnetic sensor 2 obtained by the total magnetic flux density Bs of the formula (14) are represented by the formula (15).

Since the angle θ is calculated using the equation (1), the calculated angle θ is as shown in the equation (16), and an angle deviation of Be_amp / Bm_amp × ω occurs.

If it is desired to suppress the angle deviation within K × ω, the equation (17) may be satisfied. By satisfying the equation (17), the angular deviation can be suppressed within K × ω under the condition of the angular velocity ω.

Here, K is referred to as an upper limit ratio. Further, Be_amp is the magnitude of the eddy current magnetic flux density which is the magnetic flux density generated in the magnetic sensor 2 by the eddy current of the conductive member 3, and Bm_amp is the magnet magnetic flux density which is the magnetic flux density generated in the magnetic sensor 2 by the magnet 1. Is the size of.

When the maximum angular velocity in the detection range of the angular velocity is ωmax and the maximum value of the allowable angular velocity is θmax, for example, the upper limit ratio K is given by the equation (18).

<Placement prohibited area 7 of the conductive member 3>
Therefore, as shown in the equation (17), the magnitude of the eddy current magnetic flux density generated in the magnetic sensor 2 by the eddy current of the conductive member 3 is large Be_amp with respect to the magnitude Bm_amp of the magnet magnetic flux density generated in the magnetic sensor 2 by the magnet 1. The plate-shaped member 8 is provided with an arrangement prohibited area 7 in which the conductive member 3 is not arranged so that the ratio of the above is equal to or less than a preset upper limit ratio K.

By providing the arrangement prohibition region 7 of the conductive member 3, the magnitude of the eddy current magnetic flux density Be_amp generated by the eddy current of the conductive member 3 can be reduced. Since the ratio is the upper limit ratio K or less, the angle deviation due to the eddy current magnetic flux density can be suppressed to a predetermined value or less.

As shown in the equation (18), the upper limit ratio K is set by the maximum value θmax of the allowable angle deviation. According to this configuration, the angle deviation due to the eddy current magnetic flux density can be suppressed within the maximum value θmax of the angle deviation.

As shown in FIGS. 6A and 6B, the arrangement prohibited region 7 is preferably a ring plate-shaped region or a disc-shaped region centered on the rotation axis C (center straight line). .. According to this configuration, the region where the magnetic flux of the magnet 1 interlinking with the plate-shaped member 8 becomes large is set in the arrangement prohibition region 7, and the eddy current magnetic flux density can be effectively reduced.

In order to reduce the size of the angle detection device, the distance between the magnet 1 and the plate-shaped member 8 is reduced as shown in FIG. 6A. Therefore, the arrangement prohibited region 7 is outside the circle centered on the rotation axis C (center straight line) and has the maximum outer diameter of the magnet as the diameter, and is larger than 1 times the maximum outer diameter of the magnet and 2 times or less. It is preferable that it is an annular plate-shaped region inside a circle having a diameter of.

In the arrangement prohibited region 7, the component in the axial direction Z (direction parallel to the central straight line) in the magnetic flux of the magnet 1 interlinking with each part of the plate-shaped member 8 is 1 / of the maximum value of the component in the axial direction Z of each part. It is preferable to set the effective area to be 5 times or more.

According to this configuration, the effective region in which the generation of the eddy current is large can be quantitatively set in the arrangement prohibition region 7, and the magnitude Be_amp of the eddy current magnetic flux density can be effectively reduced.

The magnetic flux density due to the eddy current generated on the circumference of the equation (10) is integrated in the radial direction to obtain the equation (11) of the eddy current magnetic flux density Be. Assuming that the conductive member 3 is arranged in the annular plate-shaped arrangement prohibition region 7 centered on the rotation axis C in FIG. 7A, the conductive member 3 is arranged according to the angle θ of the magnet 1. Although the direction of the eddy current magnetic flux density Be generated in the magnetic sensor 2 changes, the magnitude Be_amp of the eddy current magnetic flux density does not change. Therefore, the angle deviation of Be_amp / Bm_amp × ω shown in the equation (16) does not change according to the angle θ of the magnet 1. On the contrary, if the annular plate-shaped region is the arrangement prohibited region 7 in which the conductive member 3 is not provided, the angle deviation does not fluctuate according to the angle θ of the magnet 1. Therefore, if the arrangement prohibition region 7 is set so as to include the ring plate-shaped effective region shown in FIG. 5, higher-order components do not occur in the angular deviation.

On the other hand, as shown in FIG. 7B, when the conductive member 3 is partially provided in the disk-shaped arrangement prohibited region 7, the north pole or the south pole of the magnet 1 is the conductive member 3. When the angle θ approaches the portion provided with, the eddy current generated in the conductive member 3 increases, and the magnitude of the eddy current magnetic flux density Be_amp increases.

When this is expressed by a mathematical formula, it becomes equation (19). That is, a second-order disturbance occurs in the magnitude Be_amp of the eddy current magnetic flux density.

When focusing on the angular deviation, the second term may be ignored, so that the total magnetic flux density Bs is given by the equation (20).

The phase difference between the X-axis component and the Y-axis component of the equation (20) changes as in the equation (21), but if α is minute, the angular deviation becomes 0.

As shown in the equation (19), when the magnitude of the eddy current magnetic flux density includes the nth-order component, the n ± 1st-order fluctuation component is superimposed on the eddy current magnetic flux density Be, so that the eddy current magnetic flux density If the size contains a secondary component, the angle deviation will be affected. When the magnitude of the eddy current magnetic flux density includes a higher-order component of the third order or higher, the angle fluctuation is affected, but the effect on the angle deviation is small.

In FIG. 7B, the disc-shaped arrangement prohibition region 7 has been described, but even when a part of the conductive member 3 is present in the disc-shaped or ring plate-shaped arrangement prohibition region 7. , Angle deviation due to eddy current can be suppressed.

<Board 8>
The plate-shaped member 8 may be a substrate 8 on which the magnetic sensor 2 is mounted. The arrangement prohibited area 7 is provided on the substrate 8.

For example, the substrate 8 is an n-layer substrate (n is a natural number), and the arrangement prohibited region 7 is provided in at least one layer.

A circuit pattern is formed in a portion of the substrate 8 other than the arrangement prohibited area 7. The circuit pattern is composed of conductive copper foil, solder, circuit elements, and the like.

As shown in FIG. 6A, when the substrate 8 is close to the magnet 1, the arrangement prohibition region 7 becomes an annular plate-like region. Then, the circuit pattern may be provided in a region radially inside the ring plate-shaped arrangement prohibition region 7. The magnetic sensor 2 is mounted in a region radially inside the ring plate-shaped arrangement prohibition region 7. The circuit pattern may be provided in a region radially outside the arrangement prohibited region 7.

<Arrangement of magnet 1 and magnetic sensor 2>
FIG. 8 shows the difference in the magnetic field lines 10 depending on the distance between the magnet 1 and the magnetic sensor 2. When the distance between the magnet 1 and the magnetic sensor 2 is reduced as shown in FIG. 8A, the component of the magnetic sensor 2 on the XY plane becomes large, so that the position of the magnetic sensor 2 is slightly deviated from the rotation axis C. Even in this case, the distortion of the waveform is small. On the other hand, as shown in FIG. 8B, when the distance between the magnet 1 and the magnetic sensor 2 is increased, the component on the XY plane of the magnetic sensor 2 becomes smaller, so that the position of the magnetic sensor 2 is from the rotation axis C. If there is a slight deviation, the waveform will change significantly and the robustness will decrease. In the present embodiment, by arranging the magnetic sensor 2 between the magnet 1 and the conductive member 3, the distance between the magnet 1 and the magnetic sensor 2 is reduced, and the robustness against the displacement of the magnetic sensor 2 is improved. I'm raising it.

Further, since the magnetic sensor 2 detects the magnetic field of the magnet 1 that rotates about the rotation axis C, it is desirable that the magnet sensor 2 is on the rotation axis C, and the center of the circumference represented by the dotted line in FIG. The magnetic sensor 2 is located at. Therefore, the arrangement prohibited area 7 may be outside the circle centered on the magnetic sensor 2 and having the outer diameter of the magnet 1 as the radius.

<Control device for rotary electric machines equipped with an angle detection device>
The case where the angle detection device is provided in the control device 20 of the rotary electric machine will be described. As shown in FIG. 9, the magnet 1 is fixed to the rotating shaft 4 of the rotor of the rotary electric machine 25. The angle calculator 6 calculates the angle θ of the rotating shaft 4 based on the output signal of the magnetic sensor 2 and outputs it to the control device 20 of the rotating electric machine. The control device 20 of the rotary electric machine includes a voltage command calculation unit 21, a voltage application unit 22, and the like. The voltage command calculation unit 21 applies the voltage command calculation unit 21 to the winding using a known control method such as vector control based on the angle θ output from the angle calculator 6, the current detection value flowing through the winding of the rotary electric machine 25, and the like. Calculate the voltage command value to be used. The voltage application unit 22 controls on / off of a plurality of switching elements provided in the inverter based on the voltage command value, and applies a voltage to the winding.

ここで、Ｐは極対数であり、Ｉは電流ベクトルの絶対値であり、βは電流ベクトルの位相であり、Ｌｄはｄ軸自己インダクタンスであり、Ｌｑはｑ軸自己インダクタンスであり、φは磁束である。 The output torque of the rotary electric machine 25 is given by the equation (22).

Here, P is the pole logarithm, I is the absolute value of the current vector, β is the phase of the current vector, Ld is the d-axis self-inductance, Lq is the q-axis self-inductance, and φ is the magnetic flux. Is.

When the angle deviation of the angle detection device is ε, the phase β of the current vector shifts by the angle deviation ε, and the output torque of the rotary electric machine 25 becomes the equation (23) even if it is controlled correctly, and the desired equation (22) It deviates from the torque Ttgt of.

When the accuracy requirement value of the output torque is Tth, the angle deviation ε may satisfy at least Eq. (24). Then, in the equation (18), the upper limit ratio K can be set by using the angle deviation ε satisfying the equation (24) instead of the maximum value θmax of the angle deviation.

However, since the current followability deteriorates in the voltage saturation region, an angle deviation smaller than that in the equation (24) is required. The required value of the angle deviation ε may be determined according to the specifications of the voltage command calculation unit 21.

When the rotary electric machine 25 is a generator motor for a vehicle, the configuration is as shown in FIG. The rotating shaft 4 of the rotary electric machine is connected to the internal combustion engine 100 via the belt 101. When the rotary electric machine 25 functions as an electric motor, it assists the internal combustion engine 100 and serves as a driving force for the wheels. When the rotary electric machine 25 functions as a generator, the driving force of the internal combustion engine 100 is used to generate electricity. Therefore, the accuracy of the output torque is determined based on the accuracy of the driving force or the amount of power generation, and the required value of the angle deviation ε is determined accordingly. By setting the angle deviation to meet the demand, it is possible to prevent the user from unpleasant lack of driving force or excessive driving force, and insufficient power generation leading to deterioration of battery performance.

Embodiment 2.
In the first embodiment, by providing the plate-shaped member 8 with the arrangement prohibition region 7 of the conductive member 3, the angular deviation generated by the influence of the magnetic field due to the eddy current generated in the conductive member 3 is suppressed. However, in the present embodiment, by using the two magnetic sensors 2a and 2b, the angular deviation is suppressed without providing the arrangement prohibition region 7. The description of the same components as in the first embodiment will be omitted.

FIG. 11 is a diagram showing an overall configuration of the angle detection device of the present embodiment. A magnet 1 similar to that of the first embodiment is provided. A first magnetic sensor 2a and a second magnetic sensor 2b that output a signal according to the magnetic field direction of the magnet 1 are provided. The first magnetic sensor 2a and the second magnetic sensor 2b face the magnet 1 and are arranged so as to be spaced apart from each other in the axial direction Z. The conductive member 3 is arranged between the first magnetic sensor 2a and the second magnetic sensor 2b.

The first magnetic sensor 2a detects the magnetic field of the magnet 1 interlinking with the XY plane on which the sensor element is arranged, and represents the magnitude of the magnetic field in the X direction with the first sensor cosine signal Vcos1 and the magnitude of the magnetic field in the Y direction. The first sensor sine signal Vsin1 representing the value is output. The second magnetic sensor 2b detects the magnetic field of the magnet 1 interlinking with the XY plane in which the sensor element is arranged, and represents the magnitude of the magnetic field in the X direction and the second sensor cosine signal Vcos2 and the magnitude of the magnetic field in the Y direction. A second sensor sine signal Vsin2 representing the value is output. The first and second magnetic sensors 2a and 2b are arranged on the rotation axis C.

The angle calculator 6 calculates the first angle θ1 of the magnet 1 based on the output signal of the first magnetic sensor 2a, and also calculates the second angle θ1 of the magnet 1 based on the output signal of the second magnetic sensor 2b. Calculate θ2.

The angle calculator 6 A / D-converts the first sensor chord signal Vcos1 and the first sensor sinusoidal signal Vsin1 output from the first magnetic sensor 2a, and A / D conversion value Vcos_ad1 of the first sensor chord signal. And, based on the A / D conversion value Vsin_ad1 of the first sensor sine signal, for example, the first angle θ1 is calculated using the equation (25).

Further, the angle calculator 6 A / D-converts the second sensor chord signal Vcos2 and the second sensor sinusoidal signal Vsin2 output from the second magnetic sensor 2b, and A / D-converts the second sensor chord signal. Based on the value Vcos_ad2 and the A / D conversion value Vsin_ad2 of the second sensor sine signal, for example, the second angle θ2 is calculated using the equation (26).

Then, as shown in the equation (27), the angle calculator 6 averages the first angle θ1 and the second angle θ2 to calculate the final angle θ.

The effects of this embodiment will be described below. Since the arrangement of the first magnetic sensor 2a with respect to the magnet 1 and the conductive member 3 is the same as that of the magnetic sensor 2 of the first embodiment, the first sensor cosine signal Vcos1 and the first sensor of the first magnetic sensor 2a The sine signal Vsin1 is given by the equation (28) similar to the equation (15). Therefore, as shown in the equation (29), the phase of the calculated first angle θ1 advances by Be1_amp / Bm1_amp × ω.

Here, Bm1_amp is the magnitude of the first magnet magnetic flux density generated in the first magnetic sensor 2a by the magnet 1, and Be1_amp is the first vortex generated in the first magnetic sensor 2a by the eddy current of the conductive member 3. It is the magnitude of the current magnetic flux density.

On the other hand, the second magnetic sensor 2b is arranged on the side opposite to the first magnetic sensor 2a with the conductive member 3 interposed therebetween. Therefore, the direction of the magnetic field due to the eddy current interlinking with the second magnetic sensor 2b is opposite to that of the first magnetic sensor 2a. Therefore, the second sensor cosine signal Vcos2 and the second sensor sine signal Vsin2 of the second magnetic sensor 2b are out of phase with each other in the direction opposite to that of the equation (28), as shown in the equation (30). That is, as shown in the equation (31), the calculated second angle θ2 is delayed in phase by Be2_amp / Bm2_amp × ω.

Here, Bm2_amp is the magnitude of the second magnet magnetic flux density generated in the second magnetic sensor 2b by the magnet 1, and Be2_amp is the second vortex generated in the second magnetic sensor 2b by the eddy current of the conductive member 3. It is the magnitude of the current magnetic flux density.

Since the first magnetic sensor 2a and the second magnetic sensor 2b are arranged on both sides of the conductive member 3, the distance between the magnet 1 and the first magnetic sensor 2a and the distance between the magnet 1 and the second magnetic sensor 2b The difference is not large. Therefore, the magnitude Bm1_amp of the first magnet magnetic flux density and the magnitude Bm2_amp of the second magnet magnetic flux density can be regarded as equivalent as shown in the equation (32).

Further, the difference between the distance between the conductive member 3 and the first magnetic sensor 2a and the distance between the conductive member 3 and the second magnetic sensor 2b is not large. Therefore, the magnitude Be1_amp of the first eddy current magnetic flux density and the magnitude Be2_amp of the second eddy current magnetic flux density can be regarded as equivalent as shown in the equation (33).

Therefore, by calculating the average value θ of the first angle θ1 and the second angle θ2 as in the equation (27), the phase advance of the first angle θ1 in the equation (29) and the first of the equation (31). The phase lags of the two angles θ2 cancel each other out, and the angle θ in which the angle deviation is reduced can be calculated.

In particular, by arranging the first magnetic sensor 2a and the second magnetic sensor 2b symmetrically with respect to the conductive member 3, the first eddy current magnetic flux density is large Be1_amp and the second eddy current magnetic flux density is large. It is possible to improve the accuracy of the meeting by bringing it closer to Be2_amp.

Instead of equations (25) to (27), the angle calculator 6 uses equation (34) to average the angle information of the first magnetic sensor 2a and the angle information of the second magnetic sensor 2b. This may be done to calculate the final angle θ.

The conductive member 3 may be provided on the plate-shaped member. Further, the conductive member 3 may be provided on a substrate on which the first magnetic sensor 2a and the second magnetic sensor 2b are mounted. The plate-shaped member or substrate is formed in a flat plate shape orthogonal to the rotation axis C.

Further, the angle detection device according to the present embodiment may be provided in the control device of the rotary electric machine as in the first embodiment. Since the angular deviation due to the eddy current is reduced, it is possible to improve the accuracy of the output torque of the rotary electric machine as well. Further, as in the first embodiment, the rotary electric machine may be a generator motor for a vehicle. It is possible to prevent insufficient driving force or excessive driving force that is unpleasant to the user, and insufficient power generation that leads to deterioration of battery performance.

Although the present application describes various exemplary embodiments and examples, the various features, embodiments, and functions described in one or more embodiments are applications of a particular embodiment. It is not limited to, but can be applied to embodiments alone or in various combinations. Therefore, innumerable variations not illustrated are envisioned within the scope of the techniques disclosed herein. For example, it is assumed that at least one component is modified, added or omitted, and further, at least one component is extracted and combined with the components of other embodiments.

1 magnet, 2 magnetic sensor, 2a 1st magnetic sensor, 2b 2nd magnetic sensor, 3 conductive member, 4 rotating body, 7 placement prohibited area, 8 plate-shaped member, 20 rotating electric machine control device, Be_amp eddy current magnetic flux density Size, Bm_amp Magnet magnetic flux density size, C rotation axis, K upper limit ratio

Claims (14)

Magnets attached to the rotating body and
A magnetic sensor that is arranged to face the magnet and outputs a signal according to the magnetic field direction of the magnet.
A plate-shaped member having a conductive member, which is arranged so as to face the magnetic sensor, is provided.
The ratio of the magnitude of the eddy current magnetic flux density, which is the magnetic flux density generated in the magnetic sensor by the eddy current of the conductive member, to the magnitude of the magnet magnetic flux density, which is the magnetic flux density generated in the magnetic sensor by the magnet, is preset. An angle detection device in which the plate-shaped member is provided with an arrangement prohibited area in which the conductive member is not arranged so as to be equal to or less than the specified upper limit ratio. The angle detection device according to claim 1, wherein the magnetic sensor is arranged between the magnet and the plate-shaped member. The angle detection device according to claim 1 or 2, wherein the upper limit ratio is set by the maximum value of the allowable angle deviation. The arrangement prohibited region is any one of claims 1 to 3, which is a ring plate-shaped region or a disc-shaped region centered on a central straight line passing through the center of the magnet and the center of the magnetic sensor. The angle detector described. The arrangement prohibited region is outside a circle having a central straight line passing through the center of the magnet and the center of the magnetic sensor and having the maximum outer diameter of the magnet as the diameter, and is the outer diameter of the maximum outer diameter of the magnet. The angle detection device according to any one of claims 1 to 3, which is an annular plate-shaped region inside a circle having a diameter of more than 1 times and 2 times or less. In the arrangement prohibited region, a component of the magnetic flux of the magnet interlinking with each part of the plate-shaped member, which is parallel to the central straight line passing through the center of the magnet and the center of the magnetic sensor, is parallel to the central straight line of each part. The angle detection device according to any one of claims 1 to 3, which is a region in which the value is 1/5 or more of the maximum value of the above-mentioned components. The angle detection device according to any one of claims 1 to 6, wherein the plate-shaped member is a substrate on which the magnetic sensor is mounted. The substrate is an n-layer substrate (n is a natural number).
The angle detection device according to claim 7, wherein the arrangement prohibited area is provided in at least one layer. The angle detection device according to claim 7 or 8, wherein a circuit pattern is formed in a portion of the substrate other than the arrangement prohibited area. Magnets attached to the rotating body and
A first magnetic sensor and a second magnetic sensor that face the magnet, are arranged at intervals in the axial direction of the rotating body, and output a signal corresponding to the magnetic field direction of the magnet.
A conductive member arranged between the first magnetic sensor and the second magnetic sensor,
Angle detection including an angle calculator for averaging the angle information corresponding to the output signal of the first magnetic sensor and the angle information corresponding to the output signal of the second magnetic sensor to calculate the final angle information. apparatus. The angle detection device according to claim 10, wherein the first magnetic sensor and the second magnetic sensor are arranged symmetrically with respect to the conductive member. The angle detection device according to claim 10 or 11, wherein the conductive member is provided on a substrate on which the first magnetic sensor and the second magnetic sensor are mounted. A control device for a rotary electric machine that includes the angle detection device according to any one of claims 1 to 12 and controls the rotary electric machine based on the rotor angle of the rotary electric machine detected by the angle detection device. The control device for a rotary electric machine according to claim 13, wherein the rotary electric machine is a generator motor for a vehicle.

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