WO2017130984A1

WO2017130984A1 - Angle detection device and method

Info

Publication number: WO2017130984A1
Application number: PCT/JP2017/002404
Authority: WO
Inventors: 智史深瀬; 片岡　誠
Original assignee: 旭化成エレクトロニクス株式会社
Priority date: 2016-01-29
Filing date: 2017-01-24
Publication date: 2017-08-03
Also published as: DE112017000564B4; JPWO2017130984A1; JP6653336B2; DE112017000564T5

Abstract

Errors in the detected angle of an angle detection device are adjusted using a simple circuit configuration. Provided are an angle detection device for detecting the angle of a magnetic field, and a method therefor, wherein: the angle detection device is provided with a first delta-sigma modulator for performing delta-sigma modulation on a first magnetic field detection signal that corresponds to the first directional component of a magnetic field and outputting a first modulated signal, a second delta-sigma modulator for performing delta-sigma modulation on a second magnetic field detection signal that corresponds to the second directional component of the magnetic field and outputting a second modulated signal, and a loop control unit whereby a detected angle is caused by loop control to follow the first modulated signal and the second modulated signal; the loop control unit has a phase difference detection unit for detecting the phase difference of the detected angle relative to the angle indicated by the first modulated signal and the second modulated signal; and the phase difference detection unit adjusts errors in the detected angle relative to the angle of the magnetic field.

Description

Angle detection apparatus and method

The present invention relates to an angle detection apparatus and method.

Conventionally, a non-contact rotation angle sensor that detects a change in a magnetic field in the X direction and the Y direction and detects a rotation angle of a rotating magnet based on the detection result has been known. Further, since such a rotation angle sensor has an angle nonlinearity error due to sensitivity mismatch, offset error, and other-axis sensitivity, etc., adjustment of the error has been performed (see, for example, Patent Documents 1 to 5).
Patent Document 1 Japanese Patent No. 5043878 Patent Document 2 Japanese Patent No. 542045 Patent Document 3 Japanese Patent No. 5449417 Patent Document 4 Japanese Patent No. 5687223 Patent Document 5 Japanese Patent No. 4111813

Challenges to be solved

For example, the conventional adjustment of the angle nonlinearity error described in Patent Documents 3, 4, and 5 is performed by the AD conversion unit such as the delta-sigma modulator, which causes the occurrence of the angle nonlinearity error (offset, sensitivity mismatch, other axis). It is advocated to correct (sensitivity). However, such correction by an analog circuit, for example, correction in a delta-sigma modulator, reduces the effect of oversampling and causes noise aliasing.

Also, as signal processing after the delta-sigma modulator, the output modulation signal is converted into multi-bit digital data through a decimation filter, and then the multi-bit data is operated to correct the cause of the angle nonlinearity error. It is also possible to do. However, when correction of the rotation angle sensor is performed after the decimation filter, the number of multi-bit operations increases as the resolution becomes higher. In particular, when the operation is performed using a circuit such as a multiplier, the circuit scale increases. Although it depends on the circuit configuration, in general, a 1-bit × 16-bit multiplier and a 16-bit × 16-bit multiplier increase the number of gates by about 10 times and increase the circuit area. Therefore, a high-resolution rotation angle sensor with a small angle nonlinearity error and low noise is provided while suppressing an increase in circuit area.

General disclosure

(Item 1)
The angle detection device may detect the angle of the magnetic field.
The angle detection device may include a first delta-sigma modulation unit that delta-sigma modulates the first magnetic field detection signal corresponding to the first direction component of the magnetic field and outputs the first modulation signal.
The angle detection device may include a second delta-sigma modulation unit that delta-sigma-modulates a second magnetic field detection signal corresponding to the second direction component of the magnetic field and outputs a second modulation signal.
The angle detection device may include a loop control unit that causes the detection angle to follow the first modulation signal and the second modulation signal by loop control.
The loop control unit may include a phase difference detection unit that detects a phase difference of a detection angle with respect to an angle indicated by the first modulation signal and the second modulation signal.
The phase difference detection unit may adjust the error of the detection angle with respect to the angle of the magnetic field.
(Item 2)
The phase difference detection unit may output a phase difference signal indicating a phase difference based on the first modulation signal and the second modulation signal and the first feedback signal and the second feedback signal corresponding to the detection angle.
The phase difference detection unit may adjust at least one of the first feedback signal, the second feedback signal, and the phase difference signal so that the error is reduced.
(Item 3)
The phase difference detection unit may calculate an outer product of a set of the first modulation signal and the second modulation signal and a set of the first feedback signal and the second feedback signal and output a phase difference signal.
(Item 4)
The phase difference detection unit may include a first angle addition unit that adds the first adjustment angle to the detection angle.
The phase difference detection unit includes a first amplitude adjustment unit that generates a first feedback signal for adjusting an amplitude error between the first modulation signal and the second modulation signal, using the angle output from the first angle addition unit. It's okay.
(Item 5)
The phase difference detection unit may include a first angle subtraction unit that subtracts the first adjustment angle from the detection angle.
The first amplitude adjusting unit uses the sin value corresponding to the angle output from the first angle adding unit and the sin value corresponding to the angle output from the first angle subtracting unit, to calculate the first modulation signal and the second modulation signal. A first feedback signal for adjusting the amplitude error may be generated.
(Item 6)
The angle detection device may include a storage unit that can input an address based on an angle and output a sin value and a cos value corresponding to the angle as data corresponding to each angle.
The first angle addition unit and the first angle subtraction unit input an address based on an angle obtained by adding the first adjustment angle to the detection angle and an address based on an angle obtained by subtracting the first adjustment angle from the detection angle to the storage unit in different cycles. You can do it.
The first amplitude adjustment unit may receive the sin value according to the angle output from the first angle addition unit and the sin value according to the angle output from the first angle subtraction unit from the storage unit in different cycles.
The first amplitude adjustment unit may generate a first feedback signal for adjusting an amplitude error between the first modulation signal and the second modulation signal.
(Item 7)
The phase difference detection unit may include a second angle addition unit that adds the second adjustment angle to the detection angle.
The phase difference detection unit includes a second amplitude adjustment unit that generates a second feedback signal for adjusting an amplitude error between the first modulation signal and the second modulation signal, using the angle output from the second angle addition unit. It's okay.
(Item 8)
The phase difference detection unit may include a second angle subtraction unit that subtracts the second adjustment angle from the detection angle.
The second amplitude adjustment unit uses the cos value according to the angle output from the second angle addition unit and the cos value according to the angle output from the second angle subtraction unit, to generate the first modulation signal and the second modulation signal. A second feedback signal for adjusting the amplitude error may be generated.
(Item 9)
The phase difference detection unit may include an offset adjustment unit that multiplies the first feedback adjustment signal by the first offset adjustment value for adjusting the offset of the first modulation signal and adds or subtracts the phase difference.
(Item 10)
The offset adjustment unit may add or subtract the phase difference by multiplying the bit stream having the same weight as the first offset adjustment value by the first feedback signal for each bit.
(Item 11)
The offset adjustment unit may add or subtract the phase difference by multiplying the second feedback signal by a second offset adjustment value for adjusting the offset of the second modulation signal.
(Item 12)
The phase difference detection unit may include a third angle addition unit that adds the third adjustment angle to the detection angle.
The phase difference detection unit may include a third angle subtraction unit that subtracts the third adjustment angle from the detection angle.
The phase difference detection unit generates a first feedback signal using a detection angle to which the third adjustment angle is added in order to adjust the other-axis sensitivity between the first modulation signal and the second modulation signal. An other-axis sensitivity adjustment unit that generates the second feedback signal using the detected angle from which is subtracted may be included.
(Item 13)
The other-axis sensitivity adjustment unit may generate a first feedback signal based on a sin value corresponding to a detection angle to which the third adjustment angle is added.
The other-axis sensitivity adjustment unit may generate the second feedback signal based on the cos value corresponding to the detection angle obtained by subtracting the third adjustment angle.
(Item 14)
The phase difference detection unit sequentially inputs the bit stream of the first modulation signal and the bit stream of the second modulation signal for each bit, and calculates a cross product for each bit between the pair of the first feedback signal and the second feedback signal. An outer product calculation unit may be included.
(Item 15)
The loop control unit may include a loop filter that allows a frequency component equal to or lower than a predetermined frequency in the phase difference to pass.
The loop control unit may include an angle update unit that increases or decreases the detection angle according to the phase difference that has passed through the loop filter.
(Item 16)
The angle detection device may include a first magnetic sensing unit that outputs a first magnetic field detection signal corresponding to the first direction component of the magnetic field.
The angle detection device may include a second magnetic sense unit that outputs a second magnetic field detection signal corresponding to the second direction component of the magnetic field.
(Item 17)
The method may adjust the error of the detection angle of the angle detection device that detects the angle of the magnetic field.
The method may comprise the step of delta-sigma modulating the first magnetic field detection signal corresponding to the first direction component of the magnetic field and outputting the first modulated signal.
The method may comprise the step of delta-sigma modulating the second magnetic field detection signal corresponding to the second direction component of the magnetic field and outputting a second modulated signal.
The method may comprise the step of causing the detection angle to follow the first modulation signal and the second modulation signal by loop control.
The step of following may include a step of detecting a phase difference of a detection angle with respect to an angle indicated by the first modulation signal and the second modulation signal.
The step of detecting the phase difference may adjust an error of the detection angle with respect to the angle of the magnetic field.

(Item 18)
The angle detection device may detect the angle of the magnetic field.
The angle detection device may include a first delta-sigma modulation unit that delta-sigma modulates the first magnetic field detection signal corresponding to the first direction component of the magnetic field and outputs the first modulation signal.
The angle detection device may include a second delta-sigma modulation unit that delta-sigma-modulates a second magnetic field detection signal corresponding to the second direction component of the magnetic field and outputs a second modulation signal.
The angle detection device may include a loop control unit that causes the detection angle to follow the first modulation signal and the second modulation signal by loop control.
The loop control unit may adjust the error of the detection angle with respect to the angle of the magnetic field using a preset adjustment value.
(Item 19)
The method may adjust the error of the detection angle of the angle detection device that detects the angle of the magnetic field.
The method may comprise the step of delta-sigma modulating the first magnetic field detection signal corresponding to the first direction component of the magnetic field and outputting the first modulated signal.
The method may comprise the step of delta-sigma modulating the second magnetic field detection signal corresponding to the second direction component of the magnetic field and outputting a second modulated signal.
The method may comprise the step of causing the detection angle to follow the first modulation signal and the second modulation signal by loop control.
In the following step, the error of the detected angle with respect to the angle of the magnetic field may be adjusted using a preset adjustment value.

Note that the above summary of the invention does not enumerate all the necessary features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

The structural example of the rotation angle sensor 1000 which concerns on this embodiment is shown. The 1st structural example of the angle detection apparatus 10 which concerns on this embodiment is shown. 2 shows a first example of a first magnetic field detection signal Vx and a second magnetic field detection signal Vy output from the first magnetic sense unit 30 and the second magnetic sense unit 32 according to the present embodiment. The 2nd structural example of the angle detection apparatus 10 which concerns on this embodiment is shown. The 3rd structural example of the angle detection apparatus 10 which concerns on this embodiment is shown. The 2nd example of the 1st magnetic field detection signal Vx and the 2nd magnetic field detection signal Vy which the 1st magnetic sense part 30 and the 2nd magnetic sense part 32 concerning this embodiment output is shown. The 4th structural example of the angle detection apparatus 10 which concerns on this embodiment is shown. The 3rd example of the 1st magnetic field detection signal Vx and the 2nd magnetic field detection signal Vy which the 1st magnetic sense part 30 and the 2nd magnetic sense part 32 concerning this embodiment output is shown. The 5th structural example of the angle detection apparatus 10 which concerns on this embodiment is shown. The 1st modification of the phase difference detection part 210 which concerns on this embodiment is shown. The 2nd modification of the phase difference detection part 210 which concerns on this embodiment is shown.

Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

FIG. 1 shows a configuration example of a rotation angle sensor 1000 according to the present embodiment. The rotation angle sensor 1000 detects the rotation angle of the magnetic field rotating about the rotation axis in a non-contact manner. FIG. 1 shows an example of detecting the rotation angle of a magnetic field that rotates in a plane parallel to the XY plane. The rotation angle sensor 1000 includes an angle detection device 10 and a rotating magnet 20.

The angle detection device 10 detects the rotation angle of the rotating magnetic field generated by the rotating magnet 20. The angle detection device 10 is, for example, a semiconductor chip having an integrated circuit or the like. In this case, the angle detection device 10 is formed of a semiconductor such as silicon and includes a semiconductor circuit and a semiconductor element. The angle detection device 10 includes a plurality of terminals, and is electrically connected to an external substrate, circuit, wiring, and the like. A more specific configuration of the angle detection device 10 will be described later.

Rotating magnet 20 generates a rotating magnetic field. The rotating magnet 20 includes a magnet 22, a rotating shaft 24, and a motor 26. The magnet 22 rotates around the rotation shaft 24. FIG. 1 shows an example in which the magnet 22 is provided above the Z axis of the angle detection device 10. For example, the magnet 22 has a disk shape and rotates on a plane substantially parallel to the XY plane. The magnet 22 may be divided into two regions each having a semicircular cross section substantially parallel to the XY plane, and forms a magnet in which one region is an S pole and the other region is an N pole.

For example, in the angle detection device 10, the magnet 22 generates a rotating magnetic field represented by the formula (1) by rotating in a plane substantially parallel to the XY plane. Here, B indicates the absolute value of the magnetic field detected by being placed on the angle detection device 10. In the present embodiment, B is assumed to be substantially constant and handled as a constant. Further, θ represents an angle of the magnetic field direction of the rotating magnetic field with respect to a predetermined direction or a reference direction on the surface where the magnetic field rotates.
(Equation 1)
Bx (θ) = B · cos θ
By (θ) = B · sin θ

The rotating shaft 24 is provided in a direction substantially perpendicular to the XY plane. The rotating shaft 24 has one end connected to the magnet 22 and the other end connected to the motor 26. The motor 26 rotates the rotating shaft 24 and the magnet 22 connected to the rotating shaft 24. Thus, the rotation angle sensor 1000 is formed by assembling the angle detection device 10 that detects a magnetic field parallel to the XY plane and the rotation magnet 20 that rotates the magnet around the Z axis.

The angle detection device 10 detects, for example, the first direction component and the second direction component in the XY plane of the rotating magnetic field generated by the rotating magnet 20, respectively, and determines the rotation angle θ of the rotating magnet 20 at the detection timing as the first direction component. And calculating and outputting based on the second direction component. Here, the first direction and the second direction may be different directions. The first direction and the second direction are preferably two directions orthogonal to each other on the XY plane. In the present embodiment, the first direction is described as the X-axis direction, and the second direction is described as the Y-axis direction.

FIG. 2 shows a first configuration example of the angle detection apparatus 10 according to the present embodiment. The angle detection device 10 detects the angle of the input magnetic field. The angle detection device 10 of the first configuration example includes a first magnetic sense unit 30, a second magnetic sense unit 32, a first amplification unit 40, a second amplification unit 42, a first delta-sigma modulation unit 50, A second delta-sigma modulation unit 52 and a loop control unit 100 are provided.

The first magnetic sense unit 30 outputs a first magnetic field detection signal Vx corresponding to the first direction component of the input magnetic field. The second magnetic sense unit 32 outputs a second magnetic field detection signal Vy corresponding to the second direction component of the input magnetic field. Each of the first magnetic sense unit 30 and the second magnetic sense unit 32 includes a magnetic sensor that detects a magnetic field in one direction. For example, the first magnetic sense unit 30 outputs the first magnetic field detection signal Vx corresponding to the magnetic field Bx (θ) expressed by the formula (1), and the second magnetic sense unit 32 uses the formula (1). A second magnetic field detection signal Vy corresponding to the indicated magnetic field By (θ) is output. Each of the first magnetic sense unit 30 and the second magnetic sense unit 32 preferably outputs a detection signal proportional to the input magnetic field.

The first magnetic sense unit 30 and the second magnetic sense unit 32 include a Hall element, a magnetoresistive element (MR), a giant magnetoresistive element (GMR), a tunnel effect magnetoresistive element (TMR), a magnetoimpedance element (MI element), And / or an inductance sensor or the like. The first magnetic sense unit 30 and the second magnetic sense unit 32 may further include a magnetic converging plate that converges the input magnetic field.

The first amplifying unit 40 amplifies the first magnetic field detection signal Vx output from the first magnetic sense unit 30. The first amplification unit 40 supplies the amplified signal to the first delta sigma modulation unit 50. When the rotation angle of the magnetic field is detected, the amplitude value of the input magnetic field may be normalized. Here, the signal amplified by the first amplifying unit 40 is substantially equal to the magnetic field Bx (θ), and the second amplification. The signal amplified by the unit 42 is assumed to be substantially equal to the magnetic field By (θ). That is, the angle θ of the rotating magnetic field is indicated by using the first magnetic field detection signal Vx and the second magnetic field detection signal Vy.

The first delta-sigma modulation unit 50 delta-sigma-modulates the first magnetic field detection signal Vx corresponding to the first direction component of the input magnetic field and outputs a first modulation signal. The second delta sigma modulation unit 52 performs delta sigma modulation on the second magnetic field detection signal Vy corresponding to the second direction component of the input magnetic field and outputs a second modulation signal. As an example, the first delta sigma modulation unit 50 and the second delta sigma modulation unit 52 each output a bit stream having a predetermined number of 1-bit data as modulation signals.

Note that the bit stream is a signal including a predetermined number of 1-bit data, and a value obtained by integrating the 1-bit data is proportional to or substantially coincides with the amplitude value of the input signal. That is, the first delta-sigma modulation unit 50 outputs a bit stream corresponding to the magnetic field Bx (θ) as a first modulation signal, and the second delta-sigma modulation unit 52 outputs a bit stream corresponding to the magnetic field By (θ). Output as the second modulated signal.

The loop control unit 100 receives the first modulation signal and the second modulation signal output from the first delta sigma modulation unit 50 and the second delta sigma modulation unit 52, respectively, and corresponds to the received first modulation signal and second modulation signal. The angle information to be output is output as the detected angle φ. The loop control unit 100 may sequentially update and output the detection angle φ according to a clock signal or the like. The loop control unit 100 may update and output the detection angle φ by causing the detection angle to follow the first modulation signal and the second modulation signal by loop control. The loop control unit 100 includes a phase difference detection unit 110, a loop filter 140, and an angle update unit 150.

The phase difference detection unit 110 detects the phase difference of the detection angle φ with respect to the angle θ indicated by the first modulation signal and the second modulation signal. The phase difference detection unit 110 detects the phase difference between the detection angle φ output from the loop control unit 100 and the angle information θ corresponding to the first modulation signal and the second modulation signal, and then the loop control unit 100 detects the phase difference. The phase difference is output to update the angle. The phase difference detection unit 110 includes a storage unit 120 and an outer product calculation unit 130.

The storage unit 120 can input as an address based on an angle, and can output a sin value and a cos value corresponding to the angle as data corresponding to each angle. The storage unit 120 stores a sin value and a cos value respectively corresponding to a plurality of angles. The storage unit 120 may store a sin value and a cos value for each address corresponding to a plurality of angles. The storage unit 120 includes, for example, a conversion unit that receives a detection angle output from the loop control unit 100 and converts the detection angle into an address corresponding to the detection angle. That is, the storage unit 120 outputs sin φ and cos φ in response to the input of the detection angle φ.

The storage unit 120 supplies the value of sin φ corresponding to the input detection angle φ as the first feedback signal, and supplies the corresponding cos φ as the second feedback signal to the outer product calculation unit 130. For example, the storage unit 120 supplies 1 as a first feedback signal and 0 as a second feedback signal with respect to an input of π / 2 radians (or an address value corresponding to π / 2 radians). The storage unit 120 may output the first feedback signal and the second feedback signal as digital values having a predetermined number of bits.

The outer product calculation unit 130 calculates the outer product P represented by the following equation using the first feedback signal and the second feedback signal output from the storage unit 120, and the first modulation signal and the second modulation signal. The first modulation signal is B · cos θ, and the second modulation signal is B · sin θ.
(Equation 2)
P = -B · cosθ · sinφ + B · sinθ · cosφ
= B · sin (θ-φ)
≒ B ・ (θ-φ)

The outer product calculation unit 130 includes, for example, a first multiplication unit 132, a second multiplication unit 134, and a subtraction unit 136. The first multiplier 132 multiplies the first modulated signal and the first feedback signal to calculate B · cos θ · sin φ. The second multiplier 134 multiplies the second modulated signal and the second feedback signal to calculate B · sin θ · cos φ. The subtracting unit 136 subtracts the product calculated by the first multiplying unit 132 from the product calculated by the second multiplying unit 134, and calculates the outer product P expressed by Equation (2). As described above, the phase difference detection unit 110 calculates the outer product of the set of the first modulation signal and the second modulation signal and the set of the first feedback signal and the second feedback signal, and outputs the result as a phase difference signal.

Here, since the loop control unit 100 outputs the detection angle φ so as to follow the angle θ indicated by the first modulation signal and the second modulation signal, the value of θ−φ is sin (θ−φ) ≈ ( The value is small enough to approximate θ−φ). Therefore, the outer product P calculated by the outer product calculation unit 130 can be approximated to a value B · (θ−φ) that is proportional to the phase difference of the detected angle φ with respect to the angle θ, as shown in Equation (2). Since the value of B is a constant, the phase difference detection unit 110 detects the phase difference (θ−φ) between the angle θ and the detection angle φ. The phase difference detection unit 110 supplies the detected phase difference to the loop filter 140.

The loop filter 140 passes a frequency component equal to or lower than a predetermined frequency in the phase difference received from the phase difference detection unit 110. The loop filter 140 may be a low pass filter. The loop filter 140 may reduce quantization noise generated by the first delta sigma modulation unit 50 and the second delta sigma modulation unit 52. In addition, the first magnetic field detection signal Vx and the second magnetic field detection signal Vy output from the first magnetic sense unit 30 and the second magnetic sense unit 32 are modulated to obtain the first magnetic field detection signal Vx and the second magnetic field detection signal Vy. When the included DC offset signal is converted into a harmonic component, the loop filter 140 may also reduce the harmonic component.

The angle update unit 150 increases or decreases the detection angle φ according to the phase difference (θ−φ) that has passed through the loop filter. The angle updater 150 updates the detected angle φ so that the phase difference (θ−φ) approaches zero. The angle update unit 150 may include, for example, two integration units. In this case, the loop control unit 100 is a two-type servo circuit including two integration units in a closed loop circuit. As an example, the angle updating unit 150 includes two integrating units and a DCO (Digitally Controlled Oscillator) circuit.

For example, when the signal of the phase difference (θ−φ) input to the angle update unit 150 is a signal calculated using the first modulation signal and the second modulation signal of the bit stream, the angle update unit 150 The phase difference signal may be accumulated by the first accumulation unit to be a phase difference signal for each clock. Further, the phase difference for each clock (that is, for each unit time) has a dimension of an angular velocity ω (rad / s) that is a time derivative of the angle. In this case, the angle update unit 150 supplies the signal of the angular velocity ω to the DCO circuit, outputs a frequency signal corresponding to the angular velocity ω, and the second integration unit integrates the frequency signal to detect the detection angle φ. Is generated.

The second integration unit may include an up / down counter that performs up-counting and down-counting operations, and the current count value is integrated with the count value of the frequency signal up to the previous time to generate the detection angle φ. . That is, the angle updater 150 adds the current phase difference (θ−φ) to the previous detection angle φ, and calculates the detection angle φ closer to the current magnetic field rotation angle θ.

As described above, the angle detection apparatus 10 according to the present embodiment can output a more accurate detection angle φ that follows the angle θ by the feedback loop by the loop control unit 100. In the feedback loop, the loop control unit 100 feeds back the sine wave signal sin (φ) and the cosine wave signal cos (φ) corresponding to the detection angle φ to the outer product calculation unit 130, and the first modulation signal and the second modulation signal Multiply.

Here, when the first modulation signal and the second modulation signal are signed bitstreams in which one of the values +1 and −1 is temporally aligned, the outer product P shown in the equation (2) is the first modulation signal. Depending on the bit value of the second modulation signal, the value is any one of P1 to P4 expressed by the following equation. Note that the bit value of the first modulation signal is S1, and the bit value of the second modulation signal is S2.
(Equation 3)
P1 = −B · sinφ + B · cosφ S1 = + 1, S2 = + 1
P2 = B · sinφ + B · cosφ S1 = −1, S2 = + 1
P3 = −B · sinφ−B · cosφ S1 = + 1, S2 = −1
P4 = B · sinφ−B · cosφ S1 = −1, S2 = −1

That is, the angle detection apparatus 10 can calculate the outer product P by adding and subtracting the first feedback signal and the second feedback signal by supplying the first modulation signal and the second modulation signal to the outer product calculation unit 130 as a bit stream. it can. That is, the outer product calculation unit 130 sequentially inputs the bit stream of the first modulation signal and the bit stream of the second modulation signal for each bit, and performs addition / subtraction for each bit between the pair of the first feedback signal and the second feedback signal. To calculate the outer product. Thereby, the outer product calculation unit 130 can use an adder and a subtracter instead of the first multiplication unit 132 and the second multiplication unit 134, and can reduce the mounting area.

In such an angle detection device 10, the detection angle φ may include errors such as sensitivity mismatch, offset error, and other axis sensitivity. In this case, the angle detection device 10 measures these errors in the manufacturing stage and / or in a state where the detection operation is not performed, and adjusts the error of the detection angle φ according to the measurement result. However, if such an angle non-linearity error adjustment is applied to an analog circuit, such as a delta-sigma modulation unit, the effect of oversampling is reduced and noise aliasing occurs. there were.

Therefore, the loop control unit 200 according to the present embodiment adjusts the angular non-linearity error so as to realize noise reduction that cannot be realized by adjustment using an analog signal, thereby enabling high resolution. In addition, the angle nonlinearity error is adjusted without using a multiplier to prevent the circuit scale from increasing as the resolution increases. That is, the loop control unit 200 adjusts the error of the detected angle φ with respect to the magnetic field angle θ by addition and subtraction using a preset adjustment value. Next, the angle detection apparatus 10 including such a loop control unit 200 will be described.

FIG. 3 shows a first example of the first magnetic field detection signal Vx and the second magnetic field detection signal Vy output from the first magnetic sense unit 30 and the second magnetic sense unit 32 according to the present embodiment. FIG. 3 shows the first magnetic field detection signal Vx of the first magnetic sensing unit 30 in which the horizontal axis detects the first direction (X-axis direction), and the vertical axis indicates the second direction (Y-axis direction). The 2nd magnetic field detection signal Vy of the magnetic sense part 32 is shown. A signal indicated by a dotted line is an ideal magnetic field detection signal and has a substantially circular shape on the XY plane. That is, FIG. 3 shows an example in which the ideal first magnetic field detection signal Vx is B · cos θ and the ideal second magnetic field detection signal Vy is B · sin θ.

A signal indicated by a solid line indicates a magnetic field detection signal when a magnetic sensitivity mismatch occurs in the first magnetic sense unit 30 and the second magnetic sense unit 32. FIG. 3 shows a magnetic field detection signal when the first magnetic sense unit 30 has higher magnetic sensitivity than the second magnetic sense unit 32. In this case, the first magnetic field detection signal Vx can be represented as B · A · cos θ and A> 1. As described above, when a magnetic sensitivity mismatch occurs in the first magnetic sense unit 30 and the second magnetic sense unit 32, the angle detection device 10 cannot output an accurate detection angle φ.

For example, when the angle θ of the rotating magnetic field is in the range of 0 <θ <π / 2 (and π <θ <3π / 2), the first magnetic field detection signal Vx is larger than the second magnetic field detection signal Vy. The angle detection device 10 outputs a detection angle φ smaller than θ. Similarly, when the angle θ of the rotating magnetic field is in the range of π / 2 <θ <π (and 3π / 2 <θ <2π), the first magnetic field detection signal Vx is smaller than the second magnetic field detection signal Vy. The angle detection device 10 outputs a detection angle φ larger than θ.

More specifically, the outer product P shown by the equation (2) becomes as the following equation. Here, since θ≈φ, sin (θ−φ) = 0 and 2 · cos φ · sin θ = sin 2θ were set.
(Equation 4)
P = -B · A · cosθ · sinφ + B · sinθ · cosφ
= B · {−A · cosθ · sinφ + sinθ · cosφ}
= B · {A · sin (θ−φ) + (1−A) · sinθ · cosφ}
≒ -0.5 ・ B ・ (-1 + A) ・ sin2θ

As described above, the outer product P sometimes has a value even when the phase difference (θ−φ) is set to 0. Therefore, the detection angle φ includes an error corresponding to a magnetic sensitivity mismatch. . In order to adjust such an angle error, if the first magnetic field detection signal Vx is multiplied by the correction value 1 / A, the first magnetic field detection signal Vx becomes B · cos θ. Can be calculated. That is, the adjustment of the angle error can be realized by adding a multiplication circuit that multiplies the first magnetic field detection signal Vx by the correction value 1 / A. However, since the multiplication circuit has a large mounting area, the circuit scale may increase.

Therefore, in order to adjust the angle error without using the multiplication circuit, first, the outer product P is calculated by multiplying the first feedback signal by the correction value cos β.
(Equation 5)
P = −B · A · cosθ · sinφ · cosβ + B · sinθ · cosφ

Here, A = 1 / cos α. Since A and cos β are both close to 1, α≈β, that is, cos β / cos α≈1 can be approximated. Thereby, (Formula 5) Formula is expressed as the following formula.
(Equation 6)
P = −B · cos θ · sin φ · cos β / cos α + B · sin θ · cos φ
≒ -B ・ cosθ ・ sinφ + B ・ sinθ ・ cosφ
= B · sin (θ-φ)
≒ B ・ (θ-φ)

As described above, by using the correction value cos β, the outer product P can be set to 0 when the phase difference (θ−φ) is set to 0, similarly to the equation (2). Therefore, the angle detection apparatus 10 can reduce the angle error according to the magnetic sensitivity mismatch by making the detection angle φ follow θ.

Next, the multiplication of equation (5) is modified as follows.
(Equation 7)
P = −B · A · cosθ · sinφ · cosβ + B · sinθ · cosφ
= −B · A · cos θ · {sin (φ + β) + sin (φ−β)} / 2
+ B · sinθ · cosφ

(Equation 7) indicates that a multiplication such as sin φ · cos β can be calculated from an addition such as sin (φ + β) + sin (φ−β). The loop control unit 200 according to the present embodiment adjusts the error without using a multiplication circuit by using a circuit that executes the calculation of Equation (7).

FIG. 4 shows a second configuration example of the angle detection apparatus 10 according to the present embodiment. In the angle detection device 10 of the second configuration example, the same reference numerals are given to substantially the same operations as those of the angle detection device 10 of the first configuration example shown in FIG. The angle detection device 10 of the second configuration example includes a loop control unit 200. The loop control unit 200 includes a phase difference detection unit 210, a loop filter 140, and an angle update unit 150. The loop filter 140 and the angle updating unit 150 have been described with reference to FIG.

The phase difference detection unit 210 adjusts the error of the detection angle φ with respect to the magnetic field angle θ. The phase difference detection unit 210 may adjust so that the error of the detection angle φ is small. FIG. 4 shows an example in which the phase difference detection unit 210 adjusts an angular error when the first magnetic sense unit 30 has a higher magnetic sensitivity than the second magnetic sense unit 32. That is, the phase difference detection unit 210 outputs a phase difference signal indicating a phase difference based on the first modulation signal and the second modulation signal and the first feedback signal and the second feedback signal corresponding to the detection angle φ. The first feedback signal is adjusted. The phase difference detection unit 210 includes a storage unit 120, an outer product calculation unit 130, a correction value storage unit 220, a first addition / subtraction unit 230, and a first amplitude adjustment unit 240.

The correction value storage unit 220 stores a correction value β for adjusting the error of the detection angle φ. The correction value storage unit 220 may store + β and −β. In the present embodiment, the correction value β is the first adjustment angle.

The first addition / subtraction unit 230 adds and subtracts the detected angle φ based on the first adjustment angle β of the correction value storage unit 220. The first addition / subtraction unit 230 includes a first angle addition unit 232 and a first angle subtraction unit 234. The first angle addition unit 232 adds the first adjustment angle β to the detection angle φ. The first angle addition unit 232 supplies the addition result (φ + β) to the storage unit 120. The first angle subtracting unit 234 subtracts the first adjustment angle β from the detected angle φ. The first angle subtraction unit 234 supplies the subtraction result (φ−β) to the storage unit 120.

The first angle addition unit 232 and the first angle subtraction unit 234 may supply an address based on the angle to the storage unit 120. The first angle adding unit 232 and the first angle subtracting unit 234 also have an address based on an angle obtained by adding the first adjustment angle β to the detection angle φ and an address based on an angle obtained by subtracting the first adjustment angle β from the detection angle φ. May be input to the storage unit 120 in different cycles. That is, the first addition / subtraction unit 230 may sequentially supply the address value based on the angle to the storage unit 120 according to a clock signal or the like.

The storage unit 120 outputs a sine wave signal corresponding to an angle determined by the detection angle φ and the first adjustment angle β in addition to the operation described in FIG. That is, the storage unit 120 stores the value of the sine wave signal sin (φ + β) corresponding to the addition result (φ + β) of the first angle addition unit 232 and the sine corresponding to the subtraction result (φ−β) of the first angle subtraction unit 234. The value of the wave signal sin (φ−β) and the value of the cosine wave signal cos φ corresponding to the detection angle φ are output. Note that the value of the cosine wave signal cosφ is the second feedback signal as described with reference to FIG.

The first amplitude adjustment unit 240 uses the angles output by the first angle addition unit 232 and the first angle subtraction unit 234 to adjust the first feedback signal for adjusting the amplitude error of the first modulation signal and the second modulation signal. Is generated. The first amplitude adjusting unit 240 uses the sin value corresponding to the angle output from the first angle adding unit 232 and the sin value corresponding to the angle output from the first angle subtracting unit 234 to use the first modulation signal and the second A first feedback signal for adjusting the amplitude error of the modulation signal is generated.

In addition, the first amplitude adjustment unit 240 obtains the sin value according to the angle output from the first angle addition unit 232 and the sin value according to the angle output from the first angle subtraction unit 234 from the storage unit 120 in different cycles. A first feedback signal for adjusting the amplitude error of the first modulated signal and the second modulated signal may be received. The first amplitude adjustment unit 240 includes an addition unit 242 and an amplification unit 244.

The addition unit 242 adds the values of sin (φ + β) and sin (φ−β) received from the storage unit 120. The amplifying unit 244 amplifies the addition result of the adding unit 242 at a predetermined constant magnification. As an example, the amplification unit 244 may amplify the addition result of the addition unit 242 by 0.5 times. That is, the first amplitude adjusting unit 240 generates a signal obtained by halving the sum of sin (φ + β) and sin (φ−β) as the first feedback signal. As a result, the first feedback signal becomes {sin (φ + β) + sin (φ−β)} / 2. In addition, since 0.5 times in digital calculation can be realized by bit shift, the area does not increase.

The outer product calculation unit 130 calculates the outer product P using the first feedback signal and the second feedback signal, and the first modulation signal and the second modulation signal. Here, since the first feedback signal is {sin (φ + β) + sin (φ−β)} / 2, the outer product calculation unit 130 of the present embodiment calculates the outer product P shown in Equation (7). It will be. Further, the outer product P shown in the equation (7) can be approximated to the phase difference (θ−φ) as shown in the equation (6). Therefore, the outer product calculation unit 130 supplies the calculation result of the outer product P to the loop filter 140, so that the loop control unit 200 can output the detection angle φ that follows the angle θ of the rotating magnetic field.

It should be noted that the outer product calculation unit 130 can calculate the outer product P by adding and subtracting the first feedback signal and the second feedback signal, as described in FIG. Therefore, the phase difference detection unit 210 can calculate the outer product P by addition and subtraction based on the detection angle φ and the first adjustment angle β. Further, the phase difference detection unit 210 may use the sine wave signal sin (φ + β) and the sine wave signal sin (φ−β) used for generating the first feedback signal as the sine wave signal stored in the storage unit 120. it can. That is, since the phase difference detection unit 210 uses data whose address value is shifted from the detection angle φ by the first adjustment angle β, the phase difference detection unit 210 calculates the outer product P without increasing the data to be stored in the storage unit 120. be able to.

Therefore, the loop control unit 200 according to the present embodiment adjusts the angle error according to the magnetic sensitivity mismatch while preventing an increase in circuit scale and preventing an increase in data to be handled. Can do. Since the angle detection apparatus 10 shown in FIG. 4 includes such a loop control unit 200, non-contact rotation with reduced sensitivity mismatch while preventing an increase in circuit scale and an increase in data to be handled. An angle sensor can be provided.

The angle detection apparatus 10 according to the present embodiment described above is an example in which the first magnetic sense unit 30 adjusts the angular error with respect to the magnetic sensitivity mismatch when the magnetic sensitivity is higher than that of the second magnetic sense unit 32. Explained. Alternatively, the angle detection device 10 may adjust the angle error with respect to a magnetic sensitivity mismatch when the first magnetic sense unit 30 has a lower magnetic sensitivity than the second magnetic sense unit 32. . In this case, the outer product P shown by the equation (4) is expressed as the following equation.
(Equation 8)
P = -B · cosθ · sinφ + B · A · sinθ · cosφ
= B · {A · sin (θ−φ) + (− 1 + A) · cos θ · sinφ}
≒ 0.5 ・ B ・ (-1 + A) ・ sin2θ

Also in this case, the outer product P is calculated by multiplying the second feedback signal by the correction value cos β. In this way, by using the correction value cos β, the outer product P can be set to 0 when the phase difference (θ−φ) is set to 0, similarly to the equation (6). Therefore, the angle detection apparatus 10 can reduce the angle error according to the magnetic sensitivity mismatch by making the detection angle φ follow θ.
(Equation 9)
P = −B · cosθ · sinφ + B · A · sinθ · cosφ · cosβ
≒ -B ・ cosθ ・ sinφ + B ・ sinθ ・ cosφ
= B · sin (θ-φ)
≒ B ・ (θ-φ)

The equation (9) can be modified as follows.
(Equation 10)
P = −B · cosθ · sinφ + B · A · sinθ · cosφ · cosβ
= -B ・ cosθ ・ sinφ
+ B · A · sin θ · {cos (φ + β) + cos (φ−β)} / 2

(Equation 10) indicates that multiplication such as cos φ · cos β can be calculated from addition such as cos (φ + β) + cos (φ−β). The loop control unit 200 according to the present embodiment can reduce an angular error corresponding to a magnetic sensitivity mismatch by using a circuit that performs the calculation of Expression (10). Such a loop control unit 200 will be described next.

FIG. 5 shows a third configuration example of the angle detection apparatus 10 according to the present embodiment. In the angle detection device 10 of the third configuration example, the same reference numerals are given to substantially the same operations as those of the angle detection device 10 of the first configuration example and the second configuration example shown in FIGS. Is omitted. The loop control unit 200 of the third configuration example includes a phase difference detection unit 210, a loop filter 140, and an angle update unit 150. The loop filter 140 and the angle updating unit 150 have been described with reference to FIG.

FIG. 5 shows an example in which the phase difference detection unit 210 adjusts an angle error when the first magnetic sense unit 30 has a lower magnetic sensitivity than the second magnetic sense unit 32. That is, the phase difference detection unit 210 outputs a phase difference signal indicating a phase difference based on the first modulation signal and the second modulation signal and the first feedback signal and the second feedback signal corresponding to the detection angle φ. And adjusting the second feedback signal. The phase difference detection unit 210 includes a storage unit 120, an outer product calculation unit 130, a correction value storage unit 220, a second addition / subtraction unit 330, and a second amplitude adjustment unit 340.

The correction value storage unit 220 stores the second adjustment angle β. The second addition / subtraction unit 330 adds and subtracts the detected angle φ based on the second adjustment angle β of the correction value storage unit 220. The second addition / subtraction unit 330 includes a second angle addition unit 332 and a second angle subtraction unit 334. The second angle addition unit 332 adds the second adjustment angle β to the detection angle φ. The second angle addition unit 332 supplies the addition result (φ + β) to the storage unit 120. The second angle subtraction unit 334 subtracts the second adjustment angle β from the detection angle φ. The second angle subtraction unit 334 supplies the subtraction result (φ−β) to the storage unit 120.

The second angle addition unit 332 and the second angle subtraction unit 334 may supply an address based on the angle to the storage unit 120. Further, the second angle addition unit 332 and the second angle subtraction unit 334 have an address based on an angle obtained by adding the second adjustment angle β to the detection angle φ and an address based on an angle obtained by subtracting the second adjustment angle β from the detection angle φ. May be input to the storage unit 120 in different cycles. That is, the second addition / subtraction unit 330 may sequentially supply the address value based on the angle to the storage unit 120 according to the clock signal or the like.

The storage unit 120 outputs a cosine wave signal corresponding to an angle determined by the detection angle φ and the second adjustment angle β in addition to the operation described in FIG. That is, the storage unit 120 stores the value of the cosine wave signal cos (φ + β) corresponding to the addition result (φ + β) of the second angle addition unit 332 and the cosine corresponding to the subtraction result (φ−β) of the second angle subtraction unit 334. The value of the wave signal cos (φ−β) and the value of the sine wave signal sinφ corresponding to the detection angle φ are output. Note that the sine wave signal sinφ is the first feedback signal as described in FIG.

The second amplitude adjustment unit 340 uses the angles output by the second angle addition unit 332 and the second angle subtraction unit 334 to adjust the second feedback signal for adjusting the amplitude error of the first modulation signal and the second modulation signal. Is generated. The second amplitude adjustment unit 340 uses the cos value corresponding to the angle output from the second angle addition unit 332 and the cos value corresponding to the angle output from the second angle subtraction unit 334, and uses the first modulation signal and the second modulation signal. A second feedback signal for adjusting the amplitude error of the modulation signal is generated. Second amplitude adjustment unit 340 includes an addition unit 342 and an amplification unit 344.

The addition unit 342 adds the values of cos (φ + β) and cos (φ−β) received from the storage unit 120. The amplifying unit 344 amplifies the addition result of the adding unit 342 at a predetermined constant magnification. As an example, the amplification unit 344 may amplify the addition result of the addition unit 342 by 0.5 times. That is, the second amplitude adjustment unit 340 generates a signal obtained by halving the sum of cos (φ + β) and cos (φ−β) as the second feedback signal. As a result, the second feedback signal becomes {cos (φ + β) + cos (φ−β)} / 2. In addition, since 0.5 times in digital calculation can be realized by bit shift, the area does not increase.

The outer product calculation unit 130 calculates the outer product P using the first feedback signal and the second feedback signal, and the first modulation signal and the second modulation signal. Here, since the second feedback signal is {cos (φ + β) + cos (φ−β)} / 2, the outer product calculation unit 130 of the present embodiment calculates the outer product P shown in the equation (10). It will be. Further, the outer product P shown in the equation (10) can be approximated to a value based on the phase difference (θ−φ) as shown in the equation (9). Therefore, the outer product calculation unit 130 supplies the calculation result of the outer product P to the loop filter 140, so that the loop control unit 200 can output the detection angle φ that follows the angle θ of the rotating magnetic field.

It should be noted that the outer product calculation unit 130 can calculate the outer product P by adding and subtracting the first feedback signal and the second feedback signal, as described in FIG. Further, since the phase difference detection unit 210 uses data in which the address value is shifted from the detection angle φ by the second adjustment angle β, the phase difference detection unit 210 calculates the outer product P without increasing the data to be stored in the storage unit 120. be able to. Therefore, the loop control unit 200 according to the present embodiment adjusts the angle error according to the magnetic sensitivity mismatch while preventing an increase in circuit scale and preventing an increase in data to be handled. Can do.

The angle detection device 10 according to this embodiment described above has been described with respect to an example in which the angle error is adjusted with respect to the magnetic sensitivity mismatch. Instead, the angle detection device 10 may adjust the angle error with respect to the offset error. First, the offset error will be described next.

FIG. 6 shows a second example of the first magnetic field detection signal Vx and the second magnetic field detection signal Vy output from the first magnetic sense unit 30 and the second magnetic sense unit 32 according to the present embodiment. FIG. 6 shows the first magnetic field detection signal Vx of the first magnetic sensing unit 30 in which the horizontal axis detects the first direction (X-axis direction), and the vertical axis indicates the second direction (Y-axis direction). The 2nd magnetic field detection signal Vy of the magnetic sense part 32 is shown. A signal indicated by a dotted line is an ideal magnetic field detection signal and has a substantially circular shape on the XY plane. That is, FIG. 6 shows an example in which the ideal first magnetic field detection signal Vx is B · cos θ and the ideal second magnetic field detection signal Vy is B · sin θ.

A signal indicated by a solid line indicates a magnetic field detection signal when an offset error occurs in the first magnetic sense unit 30 and the second magnetic sense unit 32. FIG. 6 shows a magnetic field detection signal when the first magnetic field detection signal Vx includes an offset error of + Ox and the first magnetic field detection signal Vx includes + Oy. Thus, when an offset error occurs in the first magnetic sense unit 30 and the second magnetic sense unit 32, the angle detection device 10 cannot output an accurate detection angle φ.

More specifically, the outer product P shown by the equation (2) becomes as the following equation. Here, since θ≈φ, sin (θ−φ) = 0.
(Equation 11)
P = − (B · cos θ + Ox) · sin φ + (B · sin θ + Oy) · cos φ
= B · sin (θ-φ) -Ox · sinφ + Oy · cosφ
≒ Oy · cosφ-Ox · sinφ

As described above, the outer product P sometimes has a value even when the phase difference (θ−φ) is set to 0. Therefore, the detected angle φ includes an angle error corresponding to the offset error. Therefore, the angle detection apparatus 10 according to the present embodiment adjusts the angle error by subtracting Oy · cos φ−Ox · sin φ due to the offset error from the outer product P.

FIG. 7 shows a fourth configuration example of the angle detection apparatus 10 according to the present embodiment. In the angle detection device 10 of the fourth configuration example, the same reference numerals are given to substantially the same operations as those of the angle detection device 10 of the first configuration example shown in FIG. The angle detection device 10 of the fourth configuration example includes a loop control unit 200. The loop control unit 200 includes a phase difference detection unit 210, a loop filter 140, and an angle update unit 150. The loop filter 140 and the angle updating unit 150 have been described with reference to FIG.

FIG. 7 shows an example in which the phase difference detection unit 210 adjusts the offset error of the first magnetic sense unit 30 and the second magnetic sense unit 32. That is, the phase difference detection unit 210 outputs a phase difference signal indicating a phase difference based on the first modulation signal and the second modulation signal and the first feedback signal and the second feedback signal corresponding to the detection angle φ. Adjust the phase difference signal. The phase difference detection unit 210 includes a storage unit 120, an outer product calculation unit 130, a correction value storage unit 220, and an offset adjustment unit 410.

The storage unit 120 supplies the offset adjustment unit 410 with the value of the cosine wave signal cosφ and the value of the sine wave signal sinφ corresponding to the detection angle φ in addition to the operation described in FIG. As described with reference to FIG. 2, the outer product calculation unit 130 calculates the outer product P using the first feedback signal and the second feedback signal, and the first modulation signal and the second modulation signal. The outer product calculation unit 130 outputs the outer product P shown in Equation (11).

The correction value storage unit 220 stores correction values Ox and Oy for adjusting the error of the detected angle φ. In the present embodiment, the correction value Ox is the first offset adjustment value, and the correction value Oy is the second offset adjustment value.

The offset adjustment unit 410 may multiply the first feedback signal by the first offset adjustment value for adjusting the offset of the first modulation signal, and add or subtract the phase difference. Here, the phase difference indicates the calculation result of Equation (11). Further, the offset adjustment unit 410 may multiply the second feedback signal by a second offset adjustment value for adjusting the offset of the second modulation signal and add or subtract the phase difference. For example, the offset adjustment unit 410 includes a first multiplication unit 412, a second multiplication unit 414, and an addition unit 416.

The first multiplication unit 412 multiplies the value of sin φ received from the storage unit 120 by the first offset adjustment value received from the correction value storage unit 220. The second multiplication unit 414 multiplies the value of cos φ received from the storage unit 120 by the second offset adjustment value received from the correction value storage unit 220. The addition unit 416 adds the multiplication result of the first multiplication unit 412 to the calculation result of the outer product P received from the outer product calculation unit 130. Further, the addition unit 416 subtracts the multiplication result of the second multiplication unit 414 from the calculation result of the outer product P received from the outer product calculation unit 130.

Thereby, the offset adjustment unit 410 adjusts the outer product P calculated by the outer product calculation unit 130 to an adjustment value P ′ represented by the following equation.
(Equation 12)
P ′ = P + Ox · sinφ−Oy · cosφ
= Bsin (θ-φ)
≒ B ・ (θ-φ)

That is, the offset adjustment unit 410 can adjust the adjustment value P ′ so as to substantially match the value based on the phase difference (θ−φ). Therefore, when the phase difference detection unit 210 supplies the calculation result of the adjustment value P ′ to the loop filter 140, the loop control unit 200 can output the detection angle φ that follows the angle θ of the rotating magnetic field.

The offset adjustment unit 410 has been described using the first multiplication unit 412 and the second multiplication unit 414 to adjust the offset error. In this case, since the number of multiplication circuits increases by 2, the mounting area of the angle detection device 10 may increase. Therefore, the correction value storage unit 220 may supply the first offset adjustment value and the second offset adjustment value to the offset adjustment unit 410 as a bit stream. The correction value storage unit 220 supplies, for example, a bit stream having the same weight in which each bit corresponds to the correction value Ox as the first offset adjustment value. Similarly, the correction value storage unit 220 may supply a bit stream having the same weight in which each bit corresponds to the correction value Oy as the second offset adjustment value.

In this case, the offset adjustment unit 410 multiplies the bit stream of the first offset adjustment value received from the correction value storage unit 220 by the first feedback signal for each bit and adds it to the phase difference. Similarly, the offset adjustment unit 410 multiplies the bit stream of the second offset adjustment value received from the correction value storage unit 220 by the second feedback signal for each bit and subtracts it from the phase difference.

The multiplication using the bit stream executed by the offset adjustment unit 410 can be executed by addition / subtraction processing, similar to the operation of calculating the outer product P by addition / subtraction of the outer product calculation unit 130 described in FIG. Therefore, the offset adjustment unit 410 can adjust the offset error while preventing the mounting area from increasing. Therefore, the loop control unit 200 according to the present embodiment can adjust the detection angle error according to the offset error while preventing the circuit scale from increasing.

The angle detection apparatus 10 according to the present embodiment has been described with reference to an example of adjusting the detection angle error corresponding to the magnetic sensitivity mismatch and the offset error. Instead of this, the angle detection device 10 may adjust the error of the detection angle corresponding to the other-axis sensitivity. First, the other axis sensitivity will be described next.

FIG. 8 shows a third example of the first magnetic field detection signal Vx and the second magnetic field detection signal Vy output from the first magnetic sense unit 30 and the second magnetic sense unit 32 according to this embodiment. FIG. 8 shows the first magnetic field detection signal Vx of the first magnetic sensing unit 30 in which the horizontal axis detects the first direction (X-axis direction), and the vertical axis indicates the second direction (Y-axis direction). The 2nd magnetic field detection signal Vy of the magnetic sense part 32 is shown. A signal indicated by a dotted line is an ideal magnetic field detection signal and has a substantially circular shape on the XY plane. That is, FIG. 8 shows an example in which the ideal first magnetic field detection signal Vx is B · cos θ and the ideal second magnetic field detection signal Vy is B · sin θ.

A signal indicated by a solid line indicates a magnetic field detection signal when the other axis sensitivity occurs in the first magnetic sense unit 30 and the second magnetic sense unit 32. FIG. 8 shows a magnetic field detection signal when the first magnetic field detection signal Vx includes + B · γ · sin θ and the first magnetic field detection signal Vx includes the other axis sensitivity of + B · γ · cos θ. Thus, when the other axis sensitivity is generated in the first magnetic sense unit 30 and the second magnetic sense unit 32, the angle detection device 10 cannot output an accurate detection angle φ.

Here, the magnetic field detection signal in the case where the other-axis sensitivity is included is approximated as follows. If the angle error due to the other axis sensitivity is up to about 5 degrees, it is considered that the accuracy of such approximation is high.
(Equation 13)
Vx = B · (cos θ + γ · sin θ)
≒ B ・ (cosγ ・ cosθ + sinγ ・ sinθ)
= B · cos (θ-γ)
Vy = B · (sin θ + γ · cos θ)
≒ B ・ (cosγ ・ sinθ + sinγ ・ cosθ)
= B · sin (θ + γ)

In this case, the outer product P shown by the equation (2) is calculated as the following equation. Here, it was approximated as γ≈0.
(Equation 14)
P = −B · cos (θ−γ) · sinφ + B · sin (θ + γ) · cosφ
= B · [−0.5 · {sin (θ−γ + φ) −sin (θ−γ−φ)}
+ 0.5 · {sin (θ + γ + φ) + sin (θ + γ−φ)}]
= B · [0.5 · {−sin (θ + φ−γ) + sin (θ + γ + φ)}
+ 0.5 · {sin (θ−φ−γ) + sin (θ−φ + γ)}]
= B · {cos (θ + φ) · sinγ + sin (θ−φ) · cosγ}
≒ B ・ {cos (θ + φ) ・ γ + sin (θ−φ) ・ 1}
= B ・ γ ・ cos2θ

As described above, the outer product P sometimes has a value even when the phase difference (θ−φ) is set to 0. Therefore, the detected angle φ includes an angle error corresponding to the sensitivity of the other axis. . Therefore, the angle detection apparatus 10 according to the present embodiment adjusts so as to reduce the angle error according to the other-axis sensitivity.

As an example, the angle detection apparatus 10 adjusts the phases of the first feedback signal and the second feedback signal using δ as follows. Here, it approximated as γ≈δ≈0.
(Equation 15)
P = −B · cos (θ−γ) · sin (φ + δ)
+ B · sin (θ + γ) · cos (φ-δ)
= B · [−0.5 · {sin (θ−γ + φ + δ) −sin (θ−γ−φ−δ)}}
+ 0.5 · {sin (θ + γ + φ−δ) + sin (θ + γ−φ + δ)}]
= B · [0.5 · {−sin (θ + φ−γ + δ) + sin (θ + γ + φ−δ)}
+ 0.5 · {sin (θ−φ−γ−δ) + sin (θ−φ + γ + δ)}}
= B · {cos (θ + φ) · sin (γ−δ) + sin (θ−φ) · cos (γ + δ)}
≒ B ・ {cos (θ + φ) ・ 0 + sin (θ−φ) ・ 1}
= B · sin (θ-φ)
≒ B ・ (θ-φ)

As described above, by using the correction value δ, the outer product P can be set to 0 when the phase difference (θ−φ) is set to 0, similarly to the equation (6). Therefore, the angle detection device 10 can reduce the angle error according to the sensitivity of the other axis by causing the detection angle φ to follow θ. The angle detection apparatus 10 according to the present embodiment reduces the angle error according to the other-axis sensitivity by using a circuit that executes the calculation of Expression (15). Such an angle detection device 10 will be described next.

FIG. 9 shows a fifth configuration example of the angle detection apparatus 10 according to the present embodiment. In the angle detection device 10 of the fifth configuration example, the same reference numerals are given to substantially the same operations as those of the angle detection device 10 of the first configuration example shown in FIG. The angle detection device 10 of the fifth configuration example includes a loop control unit 200. The loop control unit 200 includes a phase difference detection unit 210, a loop filter 140, and an angle update unit 150. The loop filter 140 and the angle updating unit 150 have been described with reference to FIG.

FIG. 9 shows an example in which the phase difference detection unit 210 adjusts the other axis sensitivity of the first magnetic sense unit 30 and the second magnetic sense unit 32. That is, the phase difference detection unit 210 outputs a phase difference signal indicating a phase difference based on the first modulation signal and the second modulation signal and the first feedback signal and the second feedback signal corresponding to the detection angle φ. The first feedback signal and the second feedback signal are adjusted. The phase difference detection unit 210 includes a storage unit 120, an outer product calculation unit 130, a correction value storage unit 220, and an other-axis sensitivity adjustment unit 510.

The correction value storage unit 220 stores a correction value δ for adjusting the error of the detected angle φ. The correction value storage unit 220 may store values of + δ and −δ, respectively. In the present embodiment, the correction value δ is the third adjustment angle.

The other axis sensitivity adjustment unit 510 adds and subtracts the detected angle φ based on the third adjustment angle δ of the correction value storage unit 220. The other-axis sensitivity adjustment unit 510 includes a third angle addition unit 512 and a third angle subtraction unit 514. The third angle addition unit 512 adds the third adjustment angle δ to the detection angle φ. The third angle addition unit 512 supplies the addition result (φ + δ) to the storage unit 120. The third angle subtraction unit 514 subtracts the third adjustment angle δ from the detection angle φ. The third angle subtraction unit 514 supplies the subtraction result (φ−δ) to the storage unit 120.

The third angle addition unit 512 and the third angle subtraction unit 514 may supply an address based on the angle to the storage unit 120. Further, the third angle addition unit 512 and the third angle subtraction unit 514 are an address based on an angle obtained by adding the third adjustment angle δ to the detection angle φ and an address based on an angle obtained by subtracting the third adjustment angle δ from the detection angle φ. May be input to the storage unit 120 in different cycles. That is, the other-axis sensitivity adjustment unit 510 may sequentially supply the address value based on the angle to the storage unit 120 according to the clock signal or the like.

The storage unit 120 outputs a sin value and a cos value corresponding to an angle determined by the detection angle φ and the third adjustment angle δ. That is, the storage unit 120 stores the value of sin (φ + δ) corresponding to the addition result (φ + δ) of the third angle addition unit 512 and the cos (corresponding to the subtraction result (φ−δ) of the third angle subtraction unit 514. Output the value of φ-δ).

That is, the other axis sensitivity adjustment unit 510 generates the first feedback signal using the detected angle φ + δ added with the third adjustment angle δ to adjust the other axis sensitivity between the first modulation signal and the second modulation signal. Then, the second feedback signal is generated using the detected angle φ−δ obtained by subtracting the third adjustment angle δ. The other-axis sensitivity adjustment unit 510 generates a first feedback signal based on the sin value corresponding to the detection angle φ + δ to which the third adjustment angle δ is added, and the detection angle φ− from which the third adjustment angle δ is subtracted. A second feedback signal based on a cos value corresponding to δ is generated. FIG. 9 illustrates an example in which the other-axis sensitivity adjustment unit 510 outputs sin (φ + δ) from the storage unit 120 as the first feedback signal and outputs cos (φ−δ) from the storage unit 120 as the second feedback signal. .

The outer product calculation unit 130 calculates the outer product P using the first feedback signal and the second feedback signal, and the first modulation signal and the second modulation signal. In the outer product calculation unit 130 of the present embodiment, the other-axis sensitivity adjustment unit 510 adjusts the first feedback signal and the second feedback signal based on the third adjustment angle δ. The outer product P shown in the equation is calculated. Therefore, the outer product calculation unit 130 supplies the calculation result of the outer product P to the loop filter 140, so that the loop control unit 200 can output the detection angle φ that follows the angle θ of the rotating magnetic field.

It should be noted that the outer product calculation unit 130 can calculate the outer product P by adding and subtracting the first feedback signal and the second feedback signal, as described in FIG. Further, since the other axis sensitivity adjustment unit 510 uses data in which the address value is shifted from the detection angle φ by the third adjustment angle δ, the first feedback signal is not increased without increasing the data to be stored in the storage unit 120. And the second feedback signal can be adjusted. Therefore, the loop control unit 200 according to the present embodiment can adjust the angle error according to the sensitivity of the other axis while preventing an increase in circuit scale and preventing an increase in data to be handled. it can.

The angle detection apparatus 10 according to the present embodiment has been described with an example in which the detection angle error corresponding to any one of the magnetic sensitivity mismatch, the offset error, and the other axis sensitivity is adjusted. Instead of or in addition to this, the angle detection device 10 adjusts two or more errors among detection angle errors corresponding to any one of magnetic sensitivity mismatch, offset error, and other axis sensitivity. May be. Next, the phase difference detection unit 210 provided in the angle detection device 10 will be described.

FIG. 10 shows a first modification of the phase difference detection unit 210 according to this embodiment. In the phase difference detection unit 210 of the first modification, the same reference numerals are given to the substantially same operations as those of the phase difference detection unit 210 shown in FIGS. 4, 7, and 9, and the description thereof is omitted. The phase difference detection unit 210 of the first modification includes a storage unit 120, an outer product calculation unit 130, a correction value storage unit 220, a first addition / subtraction unit 230, a first amplitude adjustment unit 240, and an offset adjustment unit 410. The other axis sensitivity adjustment unit 510 is included.

The correction value storage unit 220 stores the first adjustment angle β, the first offset adjustment value Ox, the second offset adjustment value Oy, and the third adjustment angle δ. The correction value storage unit 220 adjusts the first adjustment angle β to the first addition / subtraction unit 230, the first offset adjustment value Ox and the second offset adjustment value Oy to the offset adjustment unit 410, and the third adjustment angle δ to other axis sensitivity adjustment. Each is supplied to the unit 510.

As described with reference to FIG. 4, the first addition / subtraction unit 230 and the first amplitude adjustment unit 240 can adjust the first feedback signal to adjust the angle error according to the magnetic sensitivity mismatch. As described with reference to FIG. 7, the offset adjusting unit 410 can adjust the outer product P calculated by the outer product calculating unit 130 to adjust the angle error according to the offset error. As described with reference to FIG. 9, the other-axis sensitivity adjustment unit 510 can adjust the first feedback signal and the second feedback signal to adjust the angle error according to the other-axis sensitivity.

Therefore, the phase difference detection unit 210 according to the present embodiment can adjust the magnetic sensitivity mismatch, the offset error, and the detection angle error corresponding to the other axis sensitivity, respectively. FIG. 10 shows an example in which the phase difference detection unit 210 adjusts the angle error when the magnetic sensitivity in the first direction is larger than that in the second direction. Instead of this, the phase difference detection unit 210 may adjust the angle error when the magnetic sensitivity in the first direction is smaller than that in the second direction. The phase difference detection unit 210 will be described next.

FIG. 11 shows a second modification of the phase difference detection unit 210 according to this embodiment. In the phase difference detection unit 210 of the second modified example, the same reference numerals are given to the substantially same operations as those of the phase difference detection unit 210 shown in FIGS. 5, 7, and 9, and the description thereof is omitted. The phase difference detection unit 210 of the second modification includes a storage unit 120, an outer product calculation unit 130, a correction value storage unit 220, a second addition / subtraction unit 330, a second amplitude adjustment unit 340, and an offset adjustment unit 410. The other axis sensitivity adjustment unit 510 is included.

That is, the phase difference detection unit 210 of the second modification example is replaced with the second addition / subtraction unit 330 in place of the first addition / subtraction unit 230 and the first amplitude adjustment unit 240 of the phase difference detection unit 210 of the first modification example shown in FIG. And a second amplitude adjustment unit 340. The correction value storage unit 220 stores the second adjustment angle β, and the correction value storage unit 220 supplies the second adjustment angle β to the second addition / subtraction unit 330. As described with reference to FIG. 5, the second addition / subtraction unit 330 and the second amplitude adjustment unit 340 can adjust the second feedback signal to adjust the angle error according to the magnetic sensitivity mismatch. The other operations of the phase difference detection unit 210 of the second modification example are substantially the same as the operations of the phase difference detection unit 210 of the first modification example shown in FIG.

As described above, the phase difference detection unit 210 according to the present embodiment can adjust the magnetic sensitivity mismatch, the offset error, and the detection angle error corresponding to the other axis sensitivity. Note that the phase difference detection unit 210 described with reference to FIGS. 10 and 11 adjusts either the first feedback signal or the second feedback signal to adjust the angle error according to the magnetic sensitivity mismatch. . Instead of this, the phase difference detection unit 210 may include a first addition / subtraction unit 230, a first amplitude adjustment unit 240, a second addition / subtraction unit 330, and a second amplitude adjustment unit 340.

In this case, the phase difference detection unit 210 adjusts the first feedback signal by the first addition / subtraction unit 230 and the first amplitude adjustment unit 240 according to the magnitudes of the magnetic sensitivities in the first direction and the second direction, and performs the second addition / subtraction. The adjustment of the second feedback signal by the unit 330 and the second amplitude adjustment unit 340 may be switched. As a result, the phase difference detection unit 210 can adjust the mismatch of the two types of magnetic sensitivities, the offset error, and the detection angle error corresponding to the other axis sensitivity.

As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

The execution order of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior”. It should be noted that they can be implemented in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the description, and the drawings, even if it is described using “first”, “next”, etc. for the sake of convenience, it means that it is essential to carry out in this order. is not.

10 angle detector, 20 rotating magnets, 22 magnets, 24 rotating shafts, 26 motors, 30 first magnetic sensing unit, 32 second magnetic sensing unit, 40 first amplification unit, 42 second amplification unit, 50 first delta sigma Modulation unit, 52 second delta sigma modulation unit, 100 loop control unit, 110 phase difference detection unit, 120 storage unit, 130 outer product calculation unit, 132 first multiplication unit, 134 second multiplication unit, 136 subtraction unit, 140 loop filter , 150 angle update unit, 200 loop control unit, 210 phase difference detection unit, 220 correction value storage unit, 230 first addition / subtraction unit, 232 first angle addition unit, 234 first angle subtraction unit, 240 first amplitude adjustment unit, 242 addition unit, 244 amplification unit, 330 second addition / subtraction unit, 332 second angle addition unit, 334 second angle subtraction unit, 3 0 second amplitude adjustment unit, 342 addition unit, 344 amplification unit, 410 offset adjustment unit, 412 first multiplication unit, 414 second multiplication unit, 416 addition unit, 510 other axis sensitivity adjustment unit, 512 third angle addition unit, 514 Third angle subtraction unit, 1000 rotation angle sensor

Claims

An angle detection device for detecting the angle of a magnetic field,
A first delta-sigma modulation unit that delta-sigma-modulates a first magnetic field detection signal corresponding to a first direction component of the magnetic field and outputs a first modulation signal;
A second delta-sigma modulation unit that delta-sigma-modulates the second magnetic field detection signal corresponding to the second direction component of the magnetic field and outputs a second modulation signal;
A loop control unit for causing a detection angle to follow the first modulation signal and the second modulation signal by loop control;
With
The loop control unit includes a phase difference detection unit that detects a phase difference of the detection angle with respect to an angle indicated by the first modulation signal and the second modulation signal,
The phase difference detection unit adjusts an error of the detection angle with respect to an angle of the magnetic field.
The phase difference detector is
Based on the first modulation signal and the second modulation signal, and the first feedback signal and the second feedback signal corresponding to the detection angle, a phase difference signal indicating the phase difference is output,
The angle detection device according to claim 1, wherein at least one of the first feedback signal, the second feedback signal, and the phase difference signal is adjusted so that the error is reduced.
The phase difference detection unit calculates an outer product of a set of the first modulation signal and the second modulation signal and a set of the first feedback signal and the second feedback signal, and outputs the phase difference signal. Item 3. The angle detection device according to Item 2.
The phase difference detector is
A first angle adder for adding a first adjustment angle to the detected angle;
And a first amplitude adjusting unit that generates the first feedback signal for adjusting an amplitude error between the first modulated signal and the second modulated signal using an angle output from the first angle adding unit. Item 4. The angle detection device according to Item 2 or 3.
The phase difference detection unit further includes a first angle subtraction unit that subtracts the first adjustment angle from the detection angle,
The first amplitude adjustment unit uses the sin value according to the angle output from the first angle addition unit and the sin value according to the angle output from the first angle subtraction unit, and the first modulation signal and the The angle detection device according to claim 4, wherein the first feedback signal for adjusting an amplitude error of the second modulation signal is generated.
A storage unit capable of inputting an address based on an angle and outputting a sin value and a cos value corresponding to the angle as data corresponding to each angle;
The first angle addition unit and the first angle subtraction unit differ in an address based on an angle obtained by adding the first adjustment angle to the detection angle and an address based on an angle obtained by subtracting the first adjustment angle from the detection angle. Input to the storage unit in a cycle,
The first amplitude adjustment unit receives a sin value according to an angle output from the first angle addition unit and a sin value according to an angle output from the first angle subtraction unit from the storage unit in different cycles, The angle detection device according to claim 5, wherein the first feedback signal for adjusting an amplitude error between the first modulation signal and the second modulation signal is generated.
The phase difference detector is
A second angle addition unit for adding a second adjustment angle to the detected angle;
And a second amplitude adjusting unit that generates the second feedback signal for adjusting an amplitude error between the first modulated signal and the second modulated signal, using an angle output from the second angle adding unit. Item 7. The angle detection device according to any one of Items 2 to 6.
The phase difference detection unit further includes a second angle subtraction unit that subtracts the second adjustment angle from the detection angle,
The second amplitude adjustment unit uses the cos value according to the angle output from the second angle addition unit and the cos value according to the angle output from the second angle subtraction unit, and uses the first modulation signal and the The angle detection device according to claim 7, wherein the second feedback signal for adjusting an amplitude error of the second modulation signal is generated.
The phase difference detection unit further includes an offset adjustment unit that multiplies the first feedback signal by a first offset adjustment value for adjusting an offset of the first modulation signal and adds or subtracts the phase difference. Item 9. The angle detection device according to any one of Items 2 to 8.
The offset adjustment unit multiplies the bit stream having the same weight as each first offset adjustment value by the first feedback signal for each bit, and adds or subtracts the phase difference to or from the phase difference. The angle detection device described in 1.
The said offset adjustment part multiplies the said 2nd feedback signal by the 2nd offset adjustment value for adjusting the offset of the said 2nd modulation signal, and adds or subtracts with respect to the said phase difference. Angle detection device.
The phase difference detector is
A third angle adder for adding a third adjustment angle to the detected angle;
A third angle subtraction unit for subtracting a third adjustment angle from the detected angle;
In order to adjust the other-axis sensitivity between the first modulation signal and the second modulation signal, the first feedback signal is generated using the detection angle added with the third adjustment angle, and the third adjustment angle The angle detection device according to any one of claims 2 to 11, further comprising: another axis sensitivity adjustment unit that generates the second feedback signal using the detection angle obtained by subtracting.
The other-axis sensitivity adjustment unit generates the first feedback signal based on a sin value corresponding to the detection angle to which the third adjustment angle is added, and according to the detection angle to which the third adjustment angle is subtracted. The angle detection device according to claim 12, wherein the second feedback signal is generated based on a cos value.
The phase difference detection unit sequentially inputs a bit stream of the first modulation signal and a bit stream of the second modulation signal for each bit, and a bit is set between the first feedback signal and the set of the second feedback signal. The angle detection device according to claim 2, further comprising an outer product calculation unit that calculates an outer product every time.
The loop control unit is configured to pass a frequency component equal to or lower than a predetermined frequency in the phase difference; and
An angle updater that increases or decreases the detection angle according to the phase difference that has passed through the loop filter;
The angle detection device according to claim 14, comprising:
A first magnetic sense unit that outputs the first magnetic field detection signal corresponding to the first direction component of the magnetic field;
A second magnetic sense unit that outputs the second magnetic field detection signal corresponding to the second direction component of the magnetic field;
The angle detection device according to any one of claims 1 to 15, further comprising:
A method of adjusting an error of a detection angle of an angle detection device that detects an angle of a magnetic field,
Delta-sigma modulating the first magnetic field detection signal corresponding to the first direction component of the magnetic field and outputting the first modulation signal;
Delta-sigma modulating a second magnetic field detection signal corresponding to the second direction component of the magnetic field and outputting a second modulation signal;
Making a detection angle follow the first modulation signal and the second modulation signal by loop control;
With
The step of following includes detecting a phase difference of the detection angle with respect to an angle indicated by the first modulation signal and the second modulation signal;
The step of detecting the phase difference adjusts an error of the detection angle with respect to an angle of the magnetic field.
An angle detection device for detecting the angle of a magnetic field,
A first delta-sigma modulation unit that delta-sigma-modulates a first magnetic field detection signal corresponding to a first direction component of the magnetic field and outputs a first modulation signal;
A second delta-sigma modulation unit that delta-sigma-modulates the second magnetic field detection signal corresponding to the second direction component of the magnetic field and outputs a second modulation signal;
A loop control unit for causing a detection angle to follow the first modulation signal and the second modulation signal by loop control;
With
The said loop control part adjusts the error of the said detection angle with respect to the angle of the said magnetic field using the preset adjustment value. Angle detection apparatus.
A method of adjusting an error of a detection angle of an angle detection device that detects an angle of a magnetic field,
Delta-sigma modulating the first magnetic field detection signal corresponding to the first direction component of the magnetic field and outputting the first modulation signal;
Delta-sigma modulating a second magnetic field detection signal corresponding to the second direction component of the magnetic field and outputting a second modulation signal;
Making a detection angle follow the first modulation signal and the second modulation signal by loop control;
With
The following step includes adjusting an error in the detection angle with respect to the angle of the magnetic field using a preset adjustment value.