JP4862485B2 - Resolver digital converter, rotation angle position detection device, and rotation machine control device - Google Patents

Description

  The present invention relates to a resolver digital converter used for a rotation angle sensor such as a resolver, and more particularly to a resolver digital converter, a rotation angle position detection device, and a rotary machine control device suitable for reducing cost and performing angle detection with high accuracy. .

  As a sensor for detecting the rotation angle of the rotor, a two-phase resolver using AC excitation, a rotation angle sensor composed of a rotor magnetized in a sine wave and two semiconductor magnetic sensors, or the like is used. The reluctance type resolver is rotatably attached to a rotation shaft such as a motor, and reactance between the rotor and the stator changes depending on the position of the rotor, and an AC signal corresponding to the change is output. A rotation angle sensor composed of a magnetized rotor and a semiconductor magnetic sensor outputs a DC signal proportional to the magnetic flux density that changes depending on the position of the rotor. The angle detection signals obtained from these rotation angle sensors are two-phase analog signals of a cos phase and a sin phase that are 90 ° out of phase, and are processed by a resolver digital converter (RDC: Resolver Digital Converter, hereinafter abbreviated as RDC). Is done.

  The RDC receives an angle detection signal from the rotation angle sensor, and outputs the rotation angle position of the rotor as position detection data which is digital data based on the input angle detection signal. There are known RDCs that obtain position detection data by an electric circuit and those that calculate position detection data by an arithmetic unit based on digital data obtained by converting an angle detection signal by an A / D converter. .

Various errors are involved in the detection of the rotation angle by the rotation angle sensor and the RDC. The angle detection signal has a difference in amplitude due to, for example, a difference in sensitivity between sensors and a difference in amplification degree in the RDC. Further, an offset is added by a detection circuit, an amplification circuit, or an A / D converter.
As a countermeasure against the error, for example, as disclosed in Patent Document 1, when the amplitudes of the two-phase angle detection signals are made to be equal in advance and the amplitudes are changed equally depending on the ambient temperature or the like, an automatic gain is obtained. Control means may be provided, and if the offset is known in advance, subtraction may be performed before the automatic gain control means.

Further, as disclosed in Patent Document 2, a rotational angle position including an error is calculated based on two-phase digital data captured by an RDC CPU from an A / D converter, and based on the calculated rotational angle position. There is also a method of reading the correction value from the ROM and calculating the rotation angle position with the error corrected.
JP 2005-43228 A JP 11-64039 A

  However, in the technique described in Patent Document 1, in order to make the amplitudes of the two-phase angle detection signals equal, two sensors having the same sensitivity are selected in advance, or the gain and offset of the electric circuit are set. Measures such as strict adjustment are required. Further, since a second-order or third-order distortion signal is generated due to a mechanical error such as the eccentricity of the rotor, the deviation of the magnetized position, or the shape error of the magnetic circuit, mechanically strict assembly and adjustment are also required. . Therefore, there is a problem that the cost becomes high.

In the technique described in Patent Document 2, since the rotational angle position is corrected based on the correction value of the ROM, the correction value must be stored according to the resolution of the RDC, and the resolution of the RDC is high. However, there is a problem that the amount of data in the ROM becomes large, requiring a mounting space and increasing the cost.
Therefore, the present invention has been made paying attention to such an unsolved problem of the conventional technology, and is a resolver digital converter, a rotation angle suitable for reducing the cost and accurately performing the angle detection. An object of the present invention is to provide a position detection device and a rotary machine control device.

[Invention 1] In order to achieve the above object, the resolver digital converter of Invention 1 outputs the angle detection signal from a rotation angle sensor that outputs two angle detection signals having different phases that change in accordance with the rotation angle of the rotor. A resolver digital converter for inputting and detecting a rotational angle position of the rotor based on the input angle detection signal, the storage means, calculating an error parameter based on the two angle detection signals, and the storage means An error parameter calculation means for storing the rotation angle position calculation means for calculating a rotation angle position of the rotor based on the error parameter of the storage means and the two angle detection signals, and each of the two angle detection signals. and a sampling value obtaining means for obtaining sampling values a _i, b _i for the error parameter calculation means, The serial two angle detection signals defined by the following equation, the sampling values a _i obtained at the sampling value obtaining means, based on b _i, the amplitude A of each phase of the fundamental wave component, B, each phase of the offset C, D: Error parameter including amplitude ratio g of second-order distortion component to fundamental wave component, initial phase α of second-order distortion component, amplitude ratio h of third-order distortion component to fundamental wave component, and initial phase β of third-order distortion component The rotation angle position calculation means sets the amplitude ratio h = 0 of the third order distortion component to the fundamental wave component, and sets the rotation angle position based on error parameters A, B, g, C, D, cos α, sin α. Is calculated.
a _i = A {cos θ _i + g cos (2θ _i + α) + h cos (3θ _i + β)} + C
b _i = B {sin θ _i −g cos (2θ _i + α) −h sin (3θ _i + β)} + D
However, i = 1,..., 6 and θ _{i + 1} = θ _i + 60 °.
With such a configuration, the error parameter calculation unit calculates the error parameter based on the two angle detection signals, and stores the calculated error parameter in the storage unit. Then, the rotation angle position calculation means calculates the rotation angle position of the rotor based on the error parameter of the storage means and the two angle detection signals.
That is, the sampling value obtaining means, the sampling values a _i, b _i is obtained by the error parameter-calculating means, the obtained sampled values a _i, based on b _i, of each phase of the fundamental wave component amplitude A, B , Offsets C and D of each phase, amplitude ratio g of second-order distortion component to fundamental wave component, initial phase α of second-order distortion component, amplitude ratio h of third-order distortion component to fundamental wave component, and third-order distortion component An error parameter including the initial phase β is calculated.
Further, the rotation angle position calculation means calculates the rotation angle position based on the error parameters A, B, g, C, D, cos α, and sin α.

[Invention 2] Furthermore, the resolver digital converter of Invention 2 inputs the angle detection signal from a rotation angle sensor that outputs two angle detection signals having different phases that change according to the rotation angle of the rotor, and inputs the angle detection signal. A resolver digital converter for detecting a rotational angle position of the rotor based on a detection signal, and calculating an error parameter for storing an error parameter based on the storage means and the two angle detection signals and storing the error parameter in the storage means Means, rotation angle position calculating means for calculating the rotation angle position of the rotor based on the error parameter of the storage means and the two angle detection signals, sampling values a _{i for} each of the two angle detection signals, and a sampling value acquisition means for acquiring a b _i, the error parameter-calculating means, the two angle detecting Was defined by the following equation No. sampled values a _i obtained at the sampling value obtaining means, based on b _i, the amplitude A of each phase of the fundamental wave component, B, each phase of the offset C, D, 2-order distortion Calculating an error parameter including an amplitude ratio g of the component to the fundamental wave component, an initial phase α of the second-order distortion component, an amplitude ratio h of the third-order distortion component to the fundamental wave component, and an initial phase β of the third-order distortion component; The rotation angle position calculation means calculates the rotation angle position based on the error parameters A, B, h, C, D, cos β, and sin β, with an amplitude ratio g = 0 of the secondary distortion component to the fundamental wave component.
a _i = A {cos θ _i + g cos (2θ _i + α) + h cos (3θ _i + β)} + C
b _i = B {sin θ _i −g cos (2θ _i + α) −h sin (3θ _i + β)} + D
However, i = 1,..., 6 and θ _{i + 1} = θ _i + 60 °.
With such a configuration, the error parameter calculation unit calculates the error parameter based on the two angle detection signals, and stores the calculated error parameter in the storage unit. Then, the rotation angle position calculation means calculates the rotation angle position of the rotor based on the error parameter of the storage means and the two angle detection signals.
That is, the sampling value obtaining means, the sampling values a _i, b _i is obtained by the error parameter-calculating means, the obtained sampled values a _i, based on b _i, of each phase of the fundamental wave component amplitude A, B , Offsets C and D of each phase, amplitude ratio g of second-order distortion component to fundamental wave component, initial phase α of second-order distortion component, amplitude ratio h of third-order distortion component to fundamental wave component, and third-order distortion component An error parameter including the initial phase β is calculated.
Further, the rotation angle position calculation means calculates the rotation angle position based on the error parameters A, B, h, C, D, cos β, and sin β.

[Invention 3 ] On the other hand, in order to achieve the above object, the rotation angle position detection device of Invention 3 includes a rotation angle sensor that outputs two angle detection signals having different phases that change according to the rotation angle of the rotor, The resolver digital converter of the invention 1 or 2 is provided.
With such a configuration, an action equivalent to that of the resolver digital converter according to the first or second aspect of the invention can be obtained.
[Invention 4 ] On the other hand, in order to achieve the above object, the rotating machine control device of Invention 4 is a rotating machine control device that controls the rotation state of the rotating machine, and includes the rotation angle position detection device of Invention 3 .
With such a configuration, an action equivalent to that of the rotation angle position detection apparatus of the invention 3 can be obtained.

As described above, according to the resolver digital converter of the first aspect, the rotation angle position is calculated based on the error parameter. Therefore, even if an error occurs in the angle detection signal, a more accurate angle than in the conventional case. The effect that it can detect is acquired. Furthermore, it is not necessary to perform electrical or mechanical strict sorting and adjustment, and the data capacity of the error parameter does not increase according to the resolution, and the storage capacity of the storage means can be reduced. The effect that can be reduced is obtained. In particular, since the error parameter can be calculated in consideration of the second-order distortion component and the third-order distortion component, it is possible to obtain an effect that more accurate angle detection can be performed. Further, by assuming that h = 0, the rotation angle position can be easily calculated.

Furthermore, according to the resolver digital converter of the invention 2, since the rotational angle position is calculated based on the error parameter, it is possible to detect the angle with higher accuracy even if an error occurs in the angle detection signal compared to the conventional case. The effect of being able to be obtained. Furthermore, it is not necessary to perform electrical or mechanical strict sorting and adjustment, and the data capacity of the error parameter does not increase according to the resolution, and the storage capacity of the storage means can be reduced. The effect that can be reduced is obtained. In particular, since the error parameter can be calculated in consideration of the second-order distortion component and the third-order distortion component, it is possible to obtain an effect that more accurate angle detection can be performed. Further, by assuming that g = 0, the rotation angle position can be easily calculated.

Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 are diagrams showing embodiments of a resolver digital converter, a rotation angle position detection device, and a rotary machine control device according to the present invention.
First, the configuration of the rotation angle position detection device will be described.
FIG. 1 is a block diagram showing the configuration of the rotation angle position detection device.
As shown in FIG. 1, the rotational angle position detection device includes a two-phase resolver 10 rotatably attached to a rotation shaft such as a motor, and a rotation shaft based on a resolver signal that is an angle detection signal from the resolver 10. And an RDC 20 that detects the rotation angle position as position detection data.

  The resolver 10 is composed of a cylindrical stator and a rotor that grips the rotation shaft and is rotatably disposed in the stator, and the reluctance between the rotor and the stator varies depending on the position of the rotor, The fundamental wave component of the reluctance change per rotation of the rotor is configured to be one cycle. That is, the rotor inner thickness center is made to coincide with the stator inner diameter center, and the rotor outer thickness center is decentered from the inner diameter center by a certain amount of eccentricity, thereby changing the rotor thickness. It changes according to the position. Therefore, when the excitation signal sinωt is given from the outside, the resolver 10 outputs a resolver signal cosθ that changes in accordance with the rotation angle of the rotation shaft and a resolver signal sinθ that is 90 ° out of phase with respect to the resolver signal cosθ.

The RDC 20 includes an excitation signal generator 11 that outputs an excitation signal sinωt to the resolver 10, an A / D converter 12 that performs A / D conversion on the resolver signal cosθ from the resolver 10, and the resolver signal sinθ from the resolver 10 as A / D. And an A / D converter 13 for conversion.
The A / D converters 12 and 13 simultaneously sample the resolver signals cos θ and sin θ at timing synchronized with the excitation signal sin ωt, and convert them into digital data a (θ) and b (θ).

The RDC 20 further includes an error parameter extraction unit 15 that extracts an error parameter, a memory 16 that stores the error parameter, a rotation angle position detection unit 17 that detects the rotation angle position θ, and outputs of the A / D converters 12 and 13. And a switch unit 18 for switching to either one of the error parameter extraction unit 15 and the rotation angle position detection unit 17.
The memory 16 may employ any type of memory, but is preferably a type of memory that can retain stored contents even when power supply is interrupted.

  The switch unit 18 is a virtual switch that models switching between an error parameter extraction process for extracting an error parameter and a rotation angle position detection process for detecting a rotation angle position, and is realized by a computer program, for example. The When the error parameter is extracted, the A / D converters 12 and 13 and the error parameter extraction unit 15 are connected to the first switching state. When the rotation angle position is detected, the A / D converters 12 and 13 and the rotation angle position detection unit are detected. 17 is switched to the second switching state where 17 is connected.

Next, the error factor of the resolver signal will be described.
FIG. 2 is a graph showing a two-phase resolver signal.
As shown in FIG. 2, the two-phase resolver signal is a signal obtained by multiplying the excitation signal sinωt by the weight of cos θ and sin θ, and the digital data a (θ), b (θ by the A / D converters 12 and 13. ).
In the resolver signal, due to mechanical errors such as rotor eccentricity, the amplitude difference of the fundamental wave component, the offset, the amplitude difference of the second-order distortion component and the initial phase error, and the amplitude difference and initial phase error of the third-order distortion component It is included. In order to correct these errors, the resolver signal is defined by the following equation (1).
a (θ) = A {cos θ + gcos (2θ + α) + hcos (3θ + β)} + C
b (θ) = B {sinθ−gcos (2θ + α) −hsin (3θ + β)} + D (1)

  In the above equation (1), A and B are the amplitudes of the fundamental (primary) components of each phase, and should be equal, but not necessarily equal. g and h are amplitude ratios of the second-order distortion component and the third-order distortion component to the fundamental wave component, and are preferably 0, but not necessarily 0. α and β are initial phases of the second-order distortion component and the third-order distortion component. C and D are offsets of each phase, and are preferably 0 but not necessarily 0.

FIG. 3 is a graph showing the result of simulating the error of the resolver signal when each error factor exists independently.
The error due to the offset mainly becomes a fundamental wave component as shown by a thin solid line in FIG. The error due to the amplitude difference (gain difference) is mainly a second-order distortion component as shown by a thick solid line. The error due to the second-order distortion component is mainly a combination of the fundamental wave component and the third-order distortion component, as indicated by a thick dotted line. The error due to the third-order distortion component is mainly a combination of the second-order distortion component and the fourth-order distortion component, as indicated by a thin dotted line.

  In the above formula (1), if A and B are equal and g, h, C and D are all 0, the rotational angle position θ can be accurately detected by a known technique. Since this is not the case, high precision and precise assembly / adjustment work of the components constituting the resolver 10 are performed so that the detection error of the detected rotation angle position is as small as possible. The object of the present embodiment is to prevent such cost increase of parts and increase in assembly / adjustment work. When there is an error factor as described above, the resolver 10 and the RDC 20 are inspected as a set (that is, the A / D converters 12 and 13 and the error parameter extraction unit 15 are connected by the switch unit 18). Then, the error parameter extraction unit 15 calculates an error parameter of each error factor and stores it in the memory 16. Then, the resolver 10 is incorporated in a rotating machine such as a motor and detects the rotational angle position (that is, the A / D converters 12 and 13 and the rotational angle position detection unit 17 are connected by the switch unit 18). Then, the rotation angle position detector 17 calculates the rotation angle position θ based on the digital data a (θ) and b (θ) acquired from the A / D converters 12 and 13 and the error parameter of the memory 16.

Next, processing of the error parameter extraction unit 15 will be described.
FIG. 4 is a flowchart showing an error parameter extraction process executed by the error parameter extraction unit 15.
The error parameter extraction process is a process realized by a computer program. When the error parameter extraction process is executed by the error parameter extraction unit 15, the process proceeds to step S100 as shown in FIG.

In step S100, sampling values a and b, which are digital data of a two-phase resolver signal, are acquired from the A / D converters 12 and 13. The resolver 10 is accurately rotated by 60 ° from a certain rotation angle position θ ₁ of the resolver 10 by a test device (not shown). Here, the value of θ ₁ is not necessarily known. When the current rotation angle position of the resolver 10 is θ _i (i = 1, 2,...), The test apparatus outputs a ready signal to the RDC 20. When the ready signal is input, the RDC 20 controls the A / D converters 12 and 13 to acquire the sampling values a and b, and outputs a completion signal to the test apparatus. When the completion signal is input, the test apparatus gives a rotation of 60 ° to the current rotation angle position θ _i and changes the rotation angle position of the resolver 10 to θ _{i + 1} = θ _i + 60 °.

Then, the processing proceeds to step S102, by repeating the operation six times the step S100, 6 pieces of sampling values for each of the two-phase resolver signals a ₁ ~a _6, b ₁ whether the ~b ₆ was obtained When it is determined that six sampling values a _{1 to} a ₆ and b _{1 to} b ₆ have been acquired (Yes), the process proceeds to step S104. Note that θ ₂ = θ ₁ + 60 °,..., Θ ₆ = θ ₁ + 300 °.
In step S106, an error parameter is calculated as follows based on the acquired sampling values a _{1 to} a ₆ and b _{1 to} b ₆ .
The following equation (2) is obtained from 12 equations obtained by substituting the sampling values a _{1 to} a ₆ and b _{1 to} b ₆ into the above equation (1).

  Further, the following expression (3) is obtained from the above expressions (1) and (2).

  If the formula of the sum of squares of trigonometric functions is applied to the cos and sin equations obtained by the above equation (3) and using A, B, Ag, and Ah as coefficients, A, B, and Ag can be calculated. Then g and h can also be calculated. That is, the following formula (4) is obtained.

  Furthermore, if a determined value is substituted into the above equation (4) and the addition theorem of the trigonometric function is applied, cos α, sin α, cos β, and sin β can be uniquely calculated. That is, the following expressions (5) and (6) are obtained.

  cosα and sinα can be calculated by solving the above equation (5) as simultaneous equations of cosα and sinα.

Similarly, cosβ and sinβ can be calculated by solving the above equation (6) as simultaneous equations of cosβ and sinβ.
In this way, all error parameters A, B, g, h, α, β, C, and D can be calculated.
Next, the process proceeds to step S106, where the calculated error parameters A, B, g, h, α, β, C, and D are stored in the memory 16, and a series of processing is terminated and the original processing is restored.
On the other hand, when it is determined in step S102 that the six sampling values a _{1 to} a ₆ and b _{1 to} b ₆ have not yet been acquired (No), the process proceeds to step S100.

Next, processing of the rotation angle position detection unit 17 will be described.
FIG. 5 is a flowchart showing a rotation angle position detection process executed by the rotation angle position detection unit 17.
The rotation angle position detection process is a process realized by a computer program. When the rotation angle position detection process is executed by the rotation angle position detection unit 17, the process proceeds to step S200 as shown in FIG.

In step S200, the sampling timer is started, and the process proceeds to step S202, where it is determined whether the sampling timing is reached based on the value of the sampling timer. If it is determined that the sampling timing is reached (Yes), step S20 is performed. 4
In step S20 4, for each of the two-phase resolver signals acquired sample values a, b from the A / D converter 12, the process proceeds to step S20 6.

In step S20 6, error parameters A memory 16, B, g, h, α, β, calculated C, D and obtained sampled values a, the rotational angular position θ on the basis of b.
(1) When the third-order distortion component is ignored and h = 0 in the above equation (1), the memory 16 stores A, B, g, C, D, cos α, and sin α as error parameters. And First, x and y are defined by the following equation (7), and x and y are calculated based on the error parameter and the sampling value.

  From x, y and the above equation (1), the following equation (8) is obtained.

  From the above equation (8), the following equation (9) is obtained.

When g, cos α, and sin α are substituted into the above equation (9), sin (θ−45 °) is obtained. Then, θ-45 ° can be calculated from cos (θ-45 °) and sin (θ-45 °), and the rotation angle position θ can be calculated.
(2) When the second-order distortion component is ignored and g = 0 in the above equation (1), the memory 16 stores A, B, h, C, D, cosβ, and sinβ as error parameters. And First, x and y are defined by the following equation (10), and x and y are calculated based on the error parameter and the sampling value.

  Φ, R, and I are defined by the following equation (11), and Φ, R, and I are calculated based on x, y, cos β, and sin β.

In the above equation (11), sign [Φ] is a sign function, and returns 1 if Φ is positive, 0 if Φ is 0, and -1 if Φ is negative. Further, COS and SIN are defined by the following equation (12), and COS and SIN are calculated based on x, y, R, and I.
COS = xR-yI, SIN = yR + xI (12)
COS and SIN have a relationship represented by the following equation (13) with respect to cos θ and sin θ of θ, respectively. This can be derived from the above equations.
COS = (x ² + y ² ) cos θ, SIN = (x ² + y ² ) sin θ (13)
Since tan θ = SIN / COS, the rotational angle position θ can be calculated by the following equation (14).
tan ⁻¹ (SIN / COS) = tan ⁻¹ (sin θ / cos θ) = θ (14)

(3) The second-order distortion component and the third-order distortion component cannot be ignored, and g ≠ 0 and h ≠ 0 in the above equation (1). The memory 16 has A, B, g, h, Assume that C, D, cosα, sinα, cosβ, and sinβ are stored. The rotational angle position θ is calculated by the above equation (1) based on the error parameter and the sampling value. However, the proper selection and calculation of the solution of at least the fifth-order equation becomes very complicated. Can be difficult.

  In this case, if a resolver is used after adjusting the axial deviation that is the cause of the secondary distortion to g = 0 based on the error parameters g, cos α, sin α, or the initial phase α relating to the secondary distortion component. The rotation angle position θ can be calculated based on the error parameters A, B, h, C, D, cos β, and sin β by the method (2). However, the adjustment for correcting the shaft misalignment is performed by moving the relative distance between the rotor and the stator by a distance proportional to -g in the direction in which the stator is rotated by 0 to α in the error parameter extraction process. Do.

As in the case of (1), it is sufficiently practical to remove the error due to the secondary distortion component assuming that there is no tertiary distortion component. In addition, as in the case of (3), it is also beneficial to suppress the second-order distortion component caused by the axis deviation sufficiently small and to obtain further accuracy to remove the error due to the third-order distortion component.
Next, the process proceeds to step S208, where the calculated rotation angle position θ is output as position detection data, and a series of processes is terminated and the original process is restored.
On the other hand, when it is determined in step S202 that the sampling timing is not reached (No), the process waits in step S202 until the sampling timing is reached.

Next, the operation of the present embodiment will be described.
First, prior to the actual operation of the RDC 20, the RDC 20 is subjected to a test operation at the time of manufacture or the like.
The error parameter extraction unit 15 repeats steps S100 and S102 to obtain _six sampling values a _{1 to} a ₆ and b _{1 to} b ₆ having different rotation angles for each of the two-phase resolver signals. Then, through steps S104 and S106, based on the acquired sampling values a _{1 to} a ₆ and b _{1 to} b ₆ , error parameters are calculated by the above equations (2) to (6), and the calculated error parameters are calculated. Is stored in the memory 16.

Next, the RDC 20 is put into actual operation.
In the rotation angle position detection unit 17, the sampling values a and b are acquired for each of the two-phase resolver signals through the steps S204 and S206 at the sampling timing, and the error parameter of the memory 16 and the acquired sampling value a, Based on b, the rotation angle position θ is calculated by the above equations (8) to (14). Then, through step S208, the calculated rotation angle position θ is output as position detection data.

Thus, in this embodiment, the resolver signal is defined by the above equation (1), and six sampling values a _{1 to} a ₆ and b _{1 to} b ₆ are obtained for each of the two-phase resolver signals. The error parameters are calculated based on the acquired sampling values a _{1 to} a ₆ and b _{1 to} b ₆ and stored in the memory. During operation, the rotational angle position θ is calculated based on the sampling values a (θ) and b (θ) using the stored error parameter.

  As a result, the rotational angle position θ is calculated based on the error parameter, so that even when an amplitude difference, an offset, and an initial phase error occur in the two-phase resolver signal, more accurate angle detection is performed as compared with the conventional case. be able to. In addition, since the error parameter is calculated in consideration of the second-order distortion component and the third-order distortion component, angle detection with higher accuracy can be performed. Furthermore, it is not necessary to perform electrical or mechanical strict sorting and adjustment, and the data capacity of the error parameter does not increase according to the resolution of the RDC 20, and the storage capacity of the memory 16 can be reduced. Cost can be reduced.

  In the above embodiment, the resolver 10 corresponds to the rotation angle sensor of the invention 1 or 5, the memory 16 corresponds to the storage means of the invention 1, and step S100 corresponds to the sampling value acquisition means of the invention 4, The error parameter extraction unit 15 and step S104 correspond to the error parameter calculation means of the first or fourth aspect. Further, the rotation angle position detector 17 and step S206 correspond to the rotation angle position calculation means of the first aspect.

In the above embodiment, it is obvious that the acquisition method and the acquisition number of the sampling values a and b are not limited, but it is preferable to construct an equation that can appropriately apply the properties of the trigonometric function. For example, in a carefully designed resolver so that the influence of nonlinearity of the magnetic circuit becomes so small that it can be ignored, the third-order distortion component can be ignored with h = 0, so that the resolver signal is expressed by the following equation (15). Define.
a (θ) = A {cos θ + g cos (2θ + α)} + C
b (θ) = B {sinθ−gcos (2θ + α)} + D (15)

Also, if the deviation between the axis of rotation of the rotor and the center of the stator can be easily suppressed, the second order distortion component can be ignored by setting g = 0, so the resolver signal is defined by the following equation (16). To do.
a (θ) = A {cos θ + hcos (3θ + β)} + C
b (θ) = B {sinθ−hsin (3θ + β)} + D (16)
In either case, the error parameter can be calculated based on less than six sampling values a and b having different rotation angles. The interval between the rotation angles may be 60 ° or may be an angle other than that.

In the above-described embodiment, the resolver 10 is used as the rotation angle sensor. However, the present invention is not limited to this, and a magnetized rotor and a magnetic element such as two Hall elements disposed in the stator with an electrical angle of 90 ° are disposed. A rotation angle sensor made of a sensor element can also be used. In this case, it is not necessary to provide the excitation signal generator 11.
In the above embodiment, the amplitude parameter of the fundamental wave component, the offset, the amplitude difference of the second-order distortion component and the initial phase error, and the error parameter for correcting the amplitude difference and the initial phase error of the third-order distortion component are set. However, the present invention is not limited to this, and an error parameter for correcting any one of these errors may be calculated.

It is a block diagram which shows the structure of a rotation angle position detection apparatus. It is a graph which shows a two-phase resolver signal. It is a graph which shows the result of having simulated the error of the resolver signal in case each error factor exists independently. 4 is a flowchart showing an error parameter extraction process executed by an error parameter extraction unit 15. 5 is a flowchart showing a rotation angle position detection process executed by a rotation angle position detection unit 17.

Explanation of symbols

10 Resolver 20 RDC
DESCRIPTION OF SYMBOLS 11 Excitation signal generator 12, 13 A / D converter 15 Error parameter extraction part 16 Memory 17 Rotation angle position detection part 18 Switch part

Claims (4)

The angle detection signal is input from a rotation angle sensor that outputs two angle detection signals having different phases that change according to the rotation angle of the rotor, and the rotation angle position of the rotor is detected based on the input angle detection signal. A resolver digital converter,
Storage means; error parameter calculation means for calculating an error parameter based on the two angle detection signals and storing the error parameter in the storage means; and the rotor based on the error parameter of the storage means and the two angle detection signals. Rotation angle position calculation means for calculating the rotation angle position of the two, and sampling value acquisition means for acquiring the sampling values a _i and b _i for each of the two angle detection signals,
The error parameter calculation means defines the two angle detection signals by the following equation, and based on the sampling values a _i and b _i acquired by the sampling value acquisition means, the amplitudes A and B of the fundamental wave components of each phase , Offsets C and D of each phase, amplitude ratio g of second-order distortion component to fundamental wave component, initial phase α of second-order distortion component, amplitude ratio h of third-order distortion component to fundamental wave component, and third-order distortion component Calculate error parameters including initial phase β ,
The rotation angle position calculation means calculates the rotation angle position based on error parameters A, B, g, C, D, cos α, and sin α, with an amplitude ratio h = 0 of the third-order distortion component to the fundamental wave component. Resolver digital converter characterized by.
a _i = A {cos θ _i + g cos (2θ _i + α) + h cos (3θ _i + β)} + C
b _i = B {sin θ _i −g cos (2θ _i + α) −h sin (3θ _i + β)} + D
However, i = 1,..., 6 and θ _{i + 1} = θ _i + 60 °. The angle detection signal is input from a rotation angle sensor that outputs two angle detection signals having different phases that change according to the rotation angle of the rotor, and the rotation angle position of the rotor is detected based on the input angle detection signal. A resolver digital converter,
Storage means; error parameter calculation means for calculating an error parameter based on the two angle detection signals and storing the error parameter in the storage means; and the rotor based on the error parameter of the storage means and the two angle detection signals. Rotation angle position calculation means for calculating the rotation angle position of the two, and sampling value acquisition means for acquiring the sampling values a _i and b _i for each of the two angle detection signals,
The error parameter calculation means defines the two angle detection signals by the following equation, and based on the sampling values a _i and b _i acquired by the sampling value acquisition means, the amplitudes A and B of the fundamental wave components of each phase , Offsets C and D of each phase, amplitude ratio g of second-order distortion component to fundamental wave component, initial phase α of second-order distortion component, amplitude ratio h of third-order distortion component to fundamental wave component, and third-order distortion component Calculate error parameters including initial phase β ,
The rotation angle position calculation means calculates the rotation angle position based on error parameters A, B, h, C, D, cos β, and sin β, with an amplitude ratio g = 0 of the secondary distortion component to the fundamental wave component. Resolver digital converter characterized by.
a _i = A {cos θ _i + g cos (2θ _i + α) + h cos (3θ _i + β)} + C
b _i = B {sin θ _i −g cos (2θ _i + α) −h sin (3θ _i + β)} + D
However, i = 1,..., 6 and θ _{i + 1} = θ _i + 60 °.   A rotation angle position detection device comprising: a rotation angle sensor that outputs two angle detection signals having different phases that change in accordance with a rotation angle of the rotor; and the resolver digital converter according to claim 1. . A rotary machine control device for controlling the rotation state of the rotary machine,
A rotation machine control device comprising the rotation angle position detection device according to claim 3.

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