WO2023053598A1 - Three-phase signal generating device, and three-phase signal generating method - Google Patents

Abstract

In one aspect of a three-phase signal generating device according to the present invention: a first complex vector, a second complex vector, and a third complex vector are calculated on the basis of instantaneous values of a first signal, a second signal, and a third signal; in the complex plane, a straight line connecting a vertex of a triangle having, as one side, a straight line connecting a vertex of the first complex vector and a vertex of the second complex vector, to a vertex of the third complex vector is calculated as a first straight line; a straight line connecting a vertex of a triangle having, as one side, a straight line connecting the vertex of the second complex vector and the vertex of the third complex vector, to the vertex of the first complex vector is calculated as a second straight line; a straight line connecting a vertex of a triangle having, as one side, a straight line connecting the vertex of the third complex vector and the vertex of the first complex vector, to the vertex of the second complex vector is calculated as a third straight line; a point of intersection of the first straight line, the second straight line, and the third straight line is calculated; and the first complex vector, the second complex vector, and the third complex vector are corrected by transforming the point of intersection to the origin of the complex plane.

Description

THREE-PHASE SIGNAL GENERATOR AND THREE-PHASE SIGNAL GENERATION METHOD

The present invention relates to a three-phase signal generation device and a three-phase signal generation method. This application claims priority based on Japanese Patent Application No. 2021-161923 filed in Japan on September 30, 2021, the content of which is incorporated herein.

Conventionally, as a motor whose rotational position can be accurately controlled, a configuration including an absolute angular position sensor such as an optical encoder and a resolver is known. However, absolute angular position sensors are large and costly. Therefore, Patent Document 1 discloses a position estimation method for estimating the rotational position of a motor using three inexpensive and small magnetic sensors without using an absolute angular position sensor.

Japanese Patent No. 6233532

In the position estimation method described in Patent Document 1, three inexpensive and small magnetic sensors can be used to estimate the mechanical angle of the rotating shaft with high accuracy, but the market sometimes requires higher accuracy. rice field.

One aspect of the three-phase signal generation device of the present invention includes: a first magnetic sensor that faces a rotating magnet and outputs a first signal indicating magnetic field strength; A second magnetic sensor outputting a second signal having a phase delay of 120° in electrical angle, and a third signal facing the magnet and outputting a third signal having a phase delay of 120° in electrical angle with respect to the second signal. and a signal processing unit that processes the first signal, the second signal, and the third signal. The signal processing unit digitally converts the first signal, the second signal, and the third signal to obtain an instantaneous value of the first signal, an instantaneous value of the second signal, and an instantaneous value of the third signal. a first complex vector that is a complex vector of the first signal based on the instantaneous value of the first signal, the instantaneous value of the second signal, and the instantaneous value of the third signal; a second process of calculating a second complex vector that is the complex vector of the second signal and a third complex vector that is the complex vector of the third signal; a third process of calculating, as a first straight line, a straight line joining a vertex of a triangle having a straight line connecting the vertex of the second complex vector and the vertex of the third complex vector as a first straight line; a fourth process of calculating, as a second straight line, a straight line connecting the vertices of a triangle having one side of a straight line connecting the vertices of the complex vector and the vertices of the third complex vector and the vertices of the first complex vector; In a plane, a straight line connecting the vertices of a triangle having one side of a straight line connecting the vertices of the third complex vector and the vertices of the first complex vector and the vertices of the second complex vector is calculated as a third straight line. 5 processing, a sixth processing of calculating an intersection point of the first straight line, the second straight line and the third straight line, and transforming the intersection point to the origin of the complex number plane, thereby obtaining the first complex vector, the and a seventh process of correcting the two complex vectors and the third complex vector.　

One aspect of the three-phase signal generation method of the present invention includes: a first magnetic sensor that faces a rotating magnet and outputs a first signal indicating magnetic field strength; A second magnetic sensor outputting a second signal having a phase delay of 120° in electrical angle, and a third signal facing the magnet and outputting a third signal having a phase delay of 120° in electrical angle with respect to the second signal. and a three-phase signal generation method using a third magnetic sensor, wherein the instantaneous value of the first signal, the second a first step of obtaining an instantaneous value of a signal and an instantaneous value of the third signal; a second step of calculating a first complex vector that is the complex vector of the signal, a second complex vector that is the complex vector of the second signal, and a third complex vector that is the complex vector of the third signal; In a plane, a straight line connecting a vertex of a triangle having one side of a straight line connecting a vertex of the first complex vector and a vertex of the second complex vector and a vertex of the third complex vector is calculated as a first straight line. 3) forming a straight line connecting the vertices of the first complex vector and the vertices of a triangle having one side of a straight line connecting the vertices of the second complex vector and the vertices of the third complex vector in the complex number plane; a fourth step of calculating as two straight lines; a vertex of a triangle having as one side a straight line connecting a vertex of the third complex vector and a vertex of the first complex vector on the complex number plane; and a vertex of the second complex vector a fifth step of calculating a straight line connecting the above as a third straight line; a sixth step of calculating an intersection point of the first straight line, the second straight line, and the third straight line; and transforming the intersection point to the origin of the complex number plane and a seventh step of correcting the first complex vector, the second complex vector and the third complex vector by:

According to the above aspects of the present invention, there are provided a three-phase signal generation device and a three-phase signal generation method that can improve the estimation accuracy (detection accuracy) of the mechanical angle of the rotating shaft.

FIG. 1 is a block diagram schematically showing the configuration of a three-phase signal generator 1 according to one embodiment of the present invention. FIG. 2 is a diagram showing an example of waveforms of the U-phase sensor signal Hu, the V-phase sensor signal Hv, and the W-phase sensor signal Hw. FIG. 3 is an enlarged view of the U-phase sensor signal Hu, the V-phase sensor signal Hv, and the W-phase sensor signal Hw included in one pole pair region shown in FIG. FIG. 4 is a diagram showing an example of waveforms of the sensor signals Hu, Hv, and Hw including in-phase signals that are noise components. FIG. 5 is a diagram showing an example of waveforms of sensor signals Hiu0, Hiv0, and Hiw0 obtained after execution of the first correction process. FIG. 6 is a diagram showing an example of waveforms of sensor signals Hiu1, Hiv1, and Hiw1 obtained after execution of the second correction process. FIG. 7 is a diagram showing an example of waveforms of sensor signals Hiu2, Hiv2, and Hiw2 obtained after execution of the third correction process. FIG. 8 is a flowchart showing three-phase signal generation processing executed by the processing unit 21 of the three-phase signal generation device 1 according to this embodiment. FIG. 9 is a complex number plane diagram used to explain the processes of steps S1 and S2 included in the three-phase signal generation process. FIG. 10 is a complex number plane diagram used to explain the processes from step S3 to step S6 included in the three-phase signal generation process. FIG. 11 is a complex number plane diagram used to explain the process of step S7 included in the three-phase signal generation process. FIG. 12 is a first diagram showing simulation results of three-phase signals obtained by three-phase signal generation processing. FIG. 13 is a second diagram showing a simulation result of a three-phase signal obtained by three-phase signal generation processing.

An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram schematically showing the configuration of a three-phase signal generation device 1 according to one embodiment of the present invention. As shown in FIG. 1 , the three-phase signal generation device 1 is a device that detects the mechanical angle (rotational angle) of a rotor shaft 110 that is the rotating shaft of the motor 100 . In this embodiment, the motor 100 is, for example, an inner rotor type three-phase brushless DC motor. Motor 100 has a rotor shaft 110 and a sensor magnet 120 .　

Sensor magnet 120 is a disc-shaped magnet attached to rotor shaft 110 . Sensor magnet 120 rotates in synchronization with rotor shaft 110 . The sensor magnet 120 has P magnetic pole pairs (P is an integer equal to or greater than 1). In this embodiment, as an example, the sensor magnet 120 has four magnetic pole pairs. A magnetic pole pair means a pair of an N pole and an S pole. That is, in this embodiment, the sensor magnet 120 has four pairs of N poles and S poles, for a total of eight magnetic poles.　

The three-phase signal generation device 1 includes a sensor group 10 and a signal processing section 20 . Although not shown in FIG. 1, a circuit board is attached to the motor 100, and the sensor group 10 and the signal processing section 20 are arranged on the circuit board. The sensor magnet 120 is arranged at a position that does not interfere with the circuit board. The sensor magnet 120 may be located inside the housing of the motor 100 or outside the housing.　

The sensor group 10 includes a first magnetic sensor 11 , a second magnetic sensor 12 and a third magnetic sensor 13 . The first magnetic sensor 11 , the second magnetic sensor 12 and the third magnetic sensor 13 are arranged on the circuit board so as to face the sensor magnet 120 . In this embodiment, the first magnetic sensor 11, the second magnetic sensor 12, and the third magnetic sensor 13 are arranged on the circuit board at intervals of 30° along the rotation direction of the sensor magnet 120. FIG. For example, the first magnetic sensor 11, the second magnetic sensor 12, and the third magnetic sensor 13 are analog output type magnetic sensors including magnetoresistive elements, such as Hall elements or linear Hall ICs. The first magnetic sensor 11 , the second magnetic sensor 12 , and the third magnetic sensor 13 each output an analog signal indicating the magnetic field intensity that changes according to the rotational position of the rotor shaft 110 , that is, the rotational position of the sensor magnet 120 .　

One cycle of the electrical angle of the analog signals output from the first magnetic sensor 11, the second magnetic sensor 12, and the third magnetic sensor 13 corresponds to 1/P of one cycle of the mechanical angle. In this embodiment, since the number of pole pairs P of the sensor magnet 120 is "4", one cycle of the electrical angle of each analog signal corresponds to 1/4 of one cycle of the mechanical angle, that is, 90° in mechanical angle. The analog signal output from the second magnetic sensor 12 has a phase lag of 120 degrees in electrical angle with respect to the analog signal output from the first magnetic sensor 11 . The analog signal output from the third magnetic sensor 13 has a phase lag of 120 degrees in electrical angle with respect to the analog signal output from the second magnetic sensor 12 .　

Hereinafter, the analog signal output from the first magnetic sensor 11 will be referred to as the U-phase sensor signal Hu, the analog signal output from the second magnetic sensor 12 will be referred to as the V-phase sensor signal Hv, and the third magnetic sensor 13 is called a W-phase sensor signal Hw.　

The first magnetic sensor 11 faces a sensor magnet 120 which is a rotating magnet, and outputs a U-phase sensor signal Hu (first signal) indicating magnetic field strength to the signal processing section 20 . The second magnetic sensor 12 faces the sensor magnet 120 and outputs to the signal processor 20 a V-phase sensor signal Hv (second signal) having a phase delay of 120° in electrical angle with respect to the U-phase sensor signal Hu. . The third magnetic sensor 13 faces the sensor magnet 120 and outputs to the signal processor 20 a W-phase sensor signal Hw (third signal) having a phase delay of 120° in electrical angle with respect to the V-phase sensor signal Hv. .　

The signal processing unit 20 is a signal processing circuit that processes the U-phase sensor signal Hu, the V-phase sensor signal Hv, and the W-phase sensor signal Hw. The signal processing unit 20 estimates the mechanical angle of the rotor shaft 110, which is the rotating shaft, based on the U-phase sensor signal Hu, the V-phase sensor signal Hv, and the W-phase sensor signal Hw. The signal processing section 20 includes a processing section 21 and a storage section 22 .　

The processing unit 21 is, for example, a microprocessor such as an MCU (Microcontroller Unit). The U-phase sensor signal Hu, the V-phase sensor signal Hv, and the W-phase sensor signal Hw are each input to the processing unit 21 . The processing unit 21 is communicably connected to the storage unit 22 via a communication bus (not shown). The processing unit 21 executes at least the following two processes according to a program pre-stored in the storage unit 22 .　

As offline processing, the processing unit 21 executes learning processing for acquiring learning data necessary for estimating the mechanical angle of the rotor shaft 110 based on the U-phase sensor signal Hu, the V-phase sensor signal Hv, and the W-phase sensor signal Hw. do. Off-line processing is processing that is executed before the three-phase signal generation device 1 is shipped from the manufacturing factory or before the three-phase signal generation device 1 is incorporated into a customer's system and put into actual operation.

As online processing, the processing unit 21 calculates the mechanical angle of the rotor shaft 110 based on the U-phase sensor signal Hu, the V-phase sensor signal Hv, the W-phase sensor signal Hw, and learning data obtained by learning processing. Execute the angle estimation process to estimate. Online processing is processing that is executed when the three-phase signal generation device 1 is incorporated into a system on the customer side and actually operated.　

The storage unit 22 is a non-volatile memory that stores programs, various setting data, the learning data, and the like necessary for causing the processing unit 21 to execute various processes. and volatile memory used as temporary storage. The nonvolatile memory is, for example, EEPROM (Electrically Erasable Programmable Read-Only Memory) or flash memory. Volatile memory is, for example, RAM (Random Access Memory).　

Before describing the learning process and the angle estimation process executed by the processing unit 21 of the three-phase signal generation device 1 configured as described above, for easy understanding of the present invention, Japanese Patent No. 6233532 The position estimation method disclosed by will be briefly described. In the following description, the position estimation method disclosed in Japanese Patent No. 6233532 may be referred to as the basic patented method. See Japanese Patent No. 6233532 for details of the basic patent method. In the following, for convenience of explanation, the basic patent method will be explained using each element shown in FIG.　

First, the learning process executed by the processing unit 21 in the basic patent method will be described. The processing unit 21 acquires instantaneous values (digital values) of the sensor signals Hu, Hv, and Hw output from the magnetic sensors 11, 12, and 13 while the sensor magnet 120 is rotated together with the rotor shaft 110. Specifically, the processing unit 21 incorporates an A/D converter, and the processing unit 21 converts the U-phase sensor signal Hu, the V-phase sensor signal Hv, and the W-phase sensor signal Hw by the A/D converter. The instantaneous values of the U-phase sensor signal Hu, the V-phase sensor signal Hv, and the W-phase sensor signal Hw are acquired by digitally converting each of them at a predetermined sampling frequency.　

During execution of the learning process, the rotor shaft 110 may be rotated by controlling the energization of the motor 100 via a motor control device (not shown). Alternatively, rotor shaft 110 may be connected to a rotating machine (not shown), and rotor shaft 110 may be rotated by the rotating machine.　

FIG. 2 is a diagram showing an example of waveforms of the U-phase sensor signal Hu, the V-phase sensor signal Hv, and the W-phase sensor signal Hw. As shown in FIG. 2, one cycle of the electrical angle of each of the sensor signals Hu, Hv, and Hw corresponds to ¼ of one cycle of the mechanical angle, that is, 90° in mechanical angle. In FIG. 2, the period from time t1 to time t5 corresponds to one mechanical angle cycle (360 degrees in mechanical angle). In FIG. 2, the period from time t1 to time t2, the period from time t2 to time t3, the period from time t3 to time t4, and the period from time t4 to time t5 are each 90 degrees mechanical angle. Equivalent to °. Further, the sensor signals Hu, Hv and Hw have a phase difference of 120 electrical degrees from each other.　

Based on the digital values of the sensor signals Hu, Hv, and Hw, the processing unit 21 detects an intersection point where two of the three sensor signals cross each other and a zero cross point where each of the three sensor signals crosses the reference signal level. points are extracted over one period of the mechanical angle. The reference signal level is, for example, ground level. When the reference signal level is ground level, the digital value of the reference signal level is "0".　

As shown in FIG. 2, the processing unit 21 divides one cycle of the mechanical angle into four pole pair regions linked to the pole pair numbers based on the extraction result of the zero crossing points. In FIG. 2, "No. C" indicates the pole pair number. As shown in FIG. 1, pole pair numbers are preassigned to the four pole pairs of the sensor magnet 120 . For example, a pole pair number “0” is assigned to a magnetic pole pair provided in a mechanical angle range of 0° to 90°. A pole pair number "1" is assigned to a magnetic pole pair provided in the mechanical angle range of 90° to 180°. A pole pair number "2" is assigned to the magnetic pole pair provided in the mechanical angle range of 180° to 270°. A pole pair number "3" is assigned to the magnetic pole pair provided in the mechanical angle range of 270° to 360°.　

For example, when the sensor signal Hu is used as a reference, the processing unit 21 assigns the zero cross point obtained at the sampling timing (time t1) at which the mechanical angle is 0° among the zero cross points of the sensor signal Hu to the pole pair number "0 ” as the starting point of the polar pair region linked to In addition, the processing unit 21 selects the zero-crossing point obtained at the sampling timing (time t2) at which the mechanical angle is 90° among the zero-crossing points of the sensor signal Hu as the pole pair associated with the pole pair number “0”. Recognize as the end point of the region. That is, the processing unit 21 determines the section between the zero-crossing point obtained at time t1 and the zero-crossing point obtained at time t2 as the pole pair region associated with the pole pair number "0".　

Of the zero crossing points of the sensor signal Hu, the processing unit 21 assigns the zero crossing point obtained at the sampling timing (time t2) at which the mechanical angle is 90° to the pole pair region associated with the pole pair number “1”. Recognize it as a starting point. Further, the processing unit 21 assigns the zero-crossing point obtained at the sampling timing (time t3) at which the mechanical angle is 180° among the zero-crossing points of the sensor signal Hu to the pole pair region associated with the pole pair number “1”. is recognized as the end point of That is, the processing unit 21 determines the section between the zero-cross point obtained at time t2 and the zero-cross point obtained at time t3 as the pole pair region associated with the pole pair number "1".　

Of the zero crossing points of the sensor signal Hu, the processing unit 21 assigns the zero crossing point obtained at the sampling timing (time t3) at which the mechanical angle is 180° to the pole pair region associated with the pole pair number “2”. Recognize it as a starting point. In addition, the processing unit 21 assigns the zero-crossing point obtained at the sampling timing (time t4) at which the mechanical angle is 270° among the zero-crossing points of the sensor signal Hu to the pole pair region associated with the pole pair number “2”. is recognized as the end point of That is, the processing unit 21 determines the section between the zero-cross point obtained at time t3 and the zero-cross point obtained at time t4 as the pole pair region associated with the pole pair number "2".　

Of the zero crossing points of the sensor signal Hu, the processing unit 21 assigns the zero crossing point obtained at the sampling timing (time t4) at which the mechanical angle is 270° to the pole pair region associated with the pole pair number “3”. Recognize it as a starting point. Further, the processing unit 21 assigns the zero-crossing point obtained at the sampling timing (time t5) corresponding to the mechanical angle of 360° among the zero-crossing points of the sensor signal Hu to the pole pair region associated with the pole pair number "3". is recognized as the end point of That is, the processing unit 21 determines the section between the zero-cross point obtained at time t4 and the zero-cross point obtained at time t5 as the pole pair region associated with the pole pair number "3".　

As shown in FIG. 2, the processing unit 21 divides each of the four polar pair regions into 12 sections associated with section numbers based on the extraction results of the intersections and zero-crossing points. In FIG. 2, "No. A" indicates the section number associated with each section. As shown in FIG. 2, 12 sections included in each of the four pole pair regions are associated with section numbers from "0" to "11."　

FIG. 3 is an enlarged view of sensor signals Hu, Hv and Hw included in one pole pair region shown in FIG. In FIG. 3, the amplitude reference value (reference signal level) is "0". In FIG. 3, the digital value of amplitude, which is a positive value, represents, as an example, the digital value of magnetic field intensity of the north pole. In addition, the negative amplitude digital value represents, for example, the digital value of the magnetic field strength of the south pole.　

In FIG. 3, points P1, P3, P5, P7, P9, P11, and P13 are zero crossings extracted from the digital values of the sensor signals Hu, Hv, and Hw included in one pole pair region. It is a point. In FIG. 3, points P2, P4, P6, P8, P10, and P12 are points of intersection extracted from the digital values of the sensor signals Hu, Hv, and Hw included in one pole pair region. be. As shown in FIG. 3, the processing unit 21 determines sections between adjacent zero cross points and intersection points as sections.　

The processing unit 21 determines the section between the zero-crossing point P1 and the intersection point P2 as the section linked to the section number "0". The processing unit 21 determines the section between the intersection point P2 and the zero-crossing point P3 as the section linked to the section number "1". The processing unit 21 determines the section between the zero-crossing point P3 and the intersection point P4 as the section linked to the section number "2". The processing unit 21 determines the section between the intersection point P4 and the zero-crossing point P5 as the section linked to the section number "3". The processing unit 21 determines the section between the zero-crossing point P5 and the intersection point P6 as the section linked to the section number "4". The processing unit 21 determines the section between the intersection point P6 and the zero crossing point P7 as the section linked to the section number "5".　

The processing unit 21 determines the section between the zero-crossing point P7 and the intersection point P8 as the section linked to the section number "6". The processing unit 21 determines the section between the intersection point P8 and the zero crossing point P9 as the section linked to the section number "7". The processing unit 21 determines the section between the zero-crossing point P9 and the intersection point P10 as the section linked to the section number "8". The processing unit 21 determines the section between the intersection point P10 and the zero crossing point P11 as the section linked to the section number "9". The processing unit 21 determines the section between the zero-crossing point P11 and the intersection point P12 as the section linked to the section number "10". The processing unit 21 determines the section between the intersection point P12 and the zero crossing point P13 as the section linked to the section number "11".　

In the following description, for example, the section assigned section number "0" will be referred to as "0 section", and the section assigned section number "11" will be referred to as "11 section". .　

As shown in FIG. 2, consecutive numbers are associated with each section number as segment numbers over the entire period of one cycle of the mechanical angle. In FIG. 2, "No. B" indicates the segment number associated with each section number. A segment is a term that represents a straight line that connects adjacent intersection points and zero cross points. In other words, a straight line connecting the start and end points of each section is called a segment. In FIG. 3, for example, the start point of the 0th section is the zero crossing point P1, and the end point of the 0th section is the intersection point P2. Therefore, the segment corresponding to the 0th section is a straight line connecting the zero cross point P1 and the intersection point P2. Similarly, in FIG. 3, for example, the starting point of the No. 1 section is the intersection point P2 and the ending point of the No. 1 section is the zero crossing point P3. Therefore, the segment corresponding to the first section is a straight line connecting the intersection point P2 and the zero crossing point P3.　

As shown in FIG. 2, in the pole pair region linked to the pole pair number "0", the segment numbers "0" to "11" are linked to the section numbers "0" to "11". be done. In the pole pair region linked to the pole pair number "1", the segment numbers "12" to "23" are linked to the section numbers "0" to "11". In the pole pair region linked to the pole pair number "2", the segment numbers "24" to "35" are linked to the section numbers "0" to "11". In the pole pair region linked to the pole pair number "3", the segment numbers "36" to "47" are linked to the section numbers "0" to "11".

In the following description, for example, the segment assigned the segment number "0" will be referred to as the "1st segment", and the segment assigned the segment number "11" will be referred to as the "11th segment". .　

The processing unit 21 generates a linear function θ(Δx) representing each segment. Δx is the length (digital value) from the starting point of the segment to any point on the segment, and θ is the mechanical angle corresponding to any point on the segment. In FIG. 3, for example, the start point of the segment corresponding to the 0th section is the zero crossing point P1, and the end point of the segment corresponding to the 0th section is the intersection point P2. Similarly, in FIG. 3, for example, the start point of the segment corresponding to section 1 is intersection point P2, and the end point of the segment corresponding to section 1 is zero cross point P3.　

For example, a linear function θ(Δx) representing a segment is represented by the following formula (1). In the following formula (1), "i" is a segment number and is an integer from 0 to 47. In the following description, the linear function θ (Δx) represented by the following equation (1) will be referred to as the mechanical angle estimation formula, and the mechanical angle θ calculated by the following equation (1) will be referred to as the mechanical angle estimated value. There is



θ(Δx)=k[i]×Δx+θres[i] (1)

In the above equation (1), k[i] is a coefficient called normalization coefficient. In other words, k[i] is a coefficient representing the slope of the i-th segment. The normalization coefficient k[i] is represented by the following formula (2). In equation (2), ΔXnorm[i] is the deviation of the digital values between the start and end points of the i-th segment. In FIG. 3, for example, ΔXnorm[i] of the segment corresponding to the 0th section is the deviation of the digital values between the zero cross point P1 and the intersection point P2. Similarly, in FIG. 3, ΔXnorm[i] of the segment corresponding to section 1, for example, is the deviation of the digital values between the intersection point P2 and the zero crossing point P3.



k[i]=θnorm[i]/ΔXnorm[i] (2)

In the above formula (2), θnorm[i] is the mechanical angle deviation between the start point and the end point of the i-th segment, and is expressed by the following formula (3). In the following equation (3), t[i] is the time between the start and end of segment i, t[0] is the time between the start and end of segment 0, and t[47 ] is the time between the start and end of the 47th segment. In FIG. 3, for example, if the segment corresponding to the 0th section is the 0th segment, t[0] is the time between the zero crossing point P1 and the crossing point P2.



θnorm[i]={t[i]/(t[0]+...+t[47])}×360[degM] (3)

In the above equation (1), θres[i] is a constant (intercept of the linear function θ(Δx)) called the angle reset value of the i-th segment. When the segment number "i" is "0", the angle reset value θres[i] is represented by the following equation (4). When the segment number "i" is one of "1" to "47", the angle reset value θres[i] is represented by the following equation (5). Note that θnorm[i] may be obtained not from t[i] as described above, but from the mechanical angle true value (for example, the mechanical angle indicated by the output signal of the encoder attached to the rotor shaft 110).



θres[i]=0[degM] (4)



θres[i]=Σ(θnorm[i−1]) (5)

The processing unit 21 acquires the correspondence between the pole pair number, the section number, and the segment number, the feature data of each section, and the mechanical angle estimation formula of each segment by performing the learning process as described above, These acquired data are stored in the storage unit 22 as learning data. Note that the feature data of each section is the magnitude relationship and positive/negative sign of the digital values of the sensor signals Hu, Hv, and Hw included in each section. In addition, the normalization coefficient k[i] and the angle reset value θres[i] that form the mechanical angle estimation formula for each segment are stored in the storage unit 22 as learning data.　

Next, the angle estimation processing executed by the processing unit 21 in the basic patent method will be described. The processing unit 21 acquires the sensor signals Hu, Hv and Hw output from the magnetic sensors 11, 12 and 13. Specifically, the processing unit 21 digitally converts each of the U-phase sensor signal Hu, the V-phase sensor signal Hv, and the W-phase sensor signal Hw at a predetermined sampling frequency by using an A/D converter, thereby obtaining a U-phase sensor signal. Digital values of the signal Hu, the V-phase sensor signal Hv, and the W-phase sensor signal Hw are acquired.　

Then, the processing unit 21 identifies the current section number and pole pair number based on the digital values of the sensor signals Hu, Hv, and Hw obtained at this sampling timing. For example, in FIG. 3, a point PHu located on the waveform of the U-phase sensor signal Hu, a point PHv located on the waveform of the V-phase sensor signal Hv, and a point PHw located on the waveform of the W-phase sensor signal Hw. , are the digital values of the sensor signals Hu, Hv, and Hw obtained at the current sampling timing. The processing unit 21 compares the feature data such as the magnitude relationship and positive/negative sign of the digital values of the points PHu, PHv, and PHw with the feature data of each section included in the learning data stored in the storage unit 22. identifies the current section (section number). In the example of FIG. 3, section number 9 is identified as the current section. In addition, this specification does not explain how to identify the pole pair number. See Japanese Patent No. 6233532 for a method of specifying the pole pair number. Assume that, for example, the pole pair number "2" is specified as the pole pair number at this sampling timing.　

Then, the processing unit 21 identifies the current segment number based on the identified current section number and pole pair number. For example, the processing unit 21 identifies the current segment number by the formula “segment number=12×pole pair number+section number”. Assume above that section number "9" is identified as the current section number and pole pair number "2" is identified as the current pole pair number. In this case, the processing unit 21 identifies the segment number "33" as the current segment number (see FIG. 2).　

The processing unit 21 reads the normalization coefficient k[i] and the angle reset value θres[i] corresponding to the specified segment number “i” from the learning data stored in the storage unit 22, and uses the above equation (1). A mechanical angle estimation value θ is calculated by the mechanical angle estimation formula represented by . Here, the digital value of the sensor signal corresponding to the identified segment is used as Δx substituted into the mechanical angle estimation formula. For example, when the segment number “33” is identified as the current segment number as described above, the processing unit 21 reads the normalization coefficient k[33] and the angle reset value θres[33] from the storage unit 22, By substituting the digital value of the point PHv (see FIG. 3) as Δx into the mechanical angle estimation formula, the mechanical angle estimated value θ at the current sampling timing is calculated.　

The above is the basic procedure for estimating the mechanical angle in the basic patented method that forms the basis of the present invention. In the basic patent method, correction processing of the sensor signals Hu, Hv, and Hw is performed in order to improve the mechanical angle estimation accuracy (accuracy of the mechanical angle estimated value θ). For example, as shown in FIG. 2, the amplitude values of the sensor signals Hu, Hv and Hw do not necessarily match. Further, for example, as shown in FIG. 4, the sensor signals Hu, Hv, and Hw may contain common-mode signals (DC signals, third harmonic signals, etc.) that are noise components. FIG. 4 is a diagram showing an example of waveforms of the sensor signals Hu, Hv, and Hw including in-phase signals that are noise components. In FIG. 4, the vertical axis indicates digital values, and the horizontal axis indicates electrical angles.　

Therefore, when the processing unit 21 in the basic patent method acquires the digital values of the sensor signals Hu, Hv, and Hw when executing the learning process and the angle estimation process, first, the following equations (6), (7), and (8) are obtained. Based on this, a first correction process is performed to remove the common-mode signal from the sensor signals Hu, Hv, and Hw.



Hiu0=Hu-(Hv+Hw)/2 (6)



Hiv0=Hv-(Hu+Hw)/2 (7)



Hiw0=Hw-(Hu+Hv)/2 (8)

In equation (6), Hiu0 is the digital value of the U-phase sensor signal obtained by performing the first correction process on the U-phase sensor signal Hu. In equation (7), Hiv0 is the digital value of the V-phase sensor signal obtained by performing the first correction process on the V-phase sensor signal Hv. In equation (8), Hiw0 is the digital value of the W-phase sensor signal obtained by performing the first correction process on the W-phase sensor signal Hw. FIG. 5 is a diagram showing an example of waveforms of sensor signals Hiu0, Hiv0, and Hiw0 obtained after execution of the first correction process. In FIG. 5, the vertical axis indicates digital values, and the horizontal axis indicates electrical angles.　

After executing the first correction process, the processing unit 21 in the basic patent method matches the amplitude values of the sensor signals Hiu0, Hiv0, and Hiw0 based on the following formulas (9) to (14). , the second correction process is executed.



Hiu1(ppn)=au_max(ppn)×Hiu0(ppn)+bu (9)



Hiu1(ppn)=au_min(ppn)×Hiu0(ppn)+bu (10)



Hiv1(ppn)=av_max(ppn)×Hiv0(ppn)+bv (11)



Hiv1(ppn)=av_min(ppn)×Hiv0(ppn)+bv (12)



Hiw1(ppn)=aw_max(ppn)×Hiw0(ppn)+bw (13)



Hiw1(ppn)=aw_min(ppn)×Hiw0(ppn)+bw (14)

The processing unit 21 performs the second correction process on the positive digital value of the U-phase sensor signal Hiu0 using the information stored in the storage unit 22 according to the above equation (9). Also, the processing unit 21 performs the second correction process on the negative digital value of the U-phase sensor signal Hiu0 using the information stored in the storage unit 22 according to the above equation (10). The processing unit 21 uses the information stored in the storage unit 22 to perform the second correction process on the positive digital value of the V-phase sensor signal Hiv0 according to the above equation (11). Further, the processing unit 21 performs the second correction process on the negative digital value of the V-phase sensor signal Hiv0 using the information stored in the storage unit 22 according to the above equation (12). The processing unit 21 uses the information stored in the storage unit 22 to perform the second correction process on the positive digital value of the W-phase sensor signal Hiw0 according to the above equation (13). Further, the processing unit 21 performs the second correction process on the negative digital value of the W-phase sensor signal Hiw0 using the information stored in the storage unit 22 according to the above equation (14).　

In equations (9) and (10), Hiu1 is the digital value of the U-phase sensor signal obtained by performing the second correction process on the U-phase sensor signal Hiu0. In equations (11) and (12), Hiv1 is the digital value of the V-phase sensor signal obtained by performing the second correction process on the V-phase sensor signal Hiv0. In equations (13) and (14), Hiw1 is the digital value of the W-phase sensor signal obtained by performing the second correction process on the W-phase sensor signal Hiw0. FIG. 6 is a diagram showing an example of waveforms of sensor signals Hiu1, Hiv1, and Hiw1 obtained after execution of the second correction process. In FIG. 6, the vertical axis indicates digital values, and the horizontal axis indicates electrical angles.　

In equations (9) to (14), ppn is a pole pair number from 0 to 3. In equations (9), (11), and (13), au_max(ppn), av_max(ppn), and aw_max(ppn) correspond to respective magnetic pole pairs stored in advance in storage unit 22. is a positive side gain correction value for the positive side digital value for one electrical angle cycle. In equations (10), (12), and (14), au_min(ppn), av_min(ppn), and aw_min(ppn) correspond to respective magnetic pole pairs pre-stored in storage unit 22. This is a negative side gain correction value for a negative side digital value for one electrical angle cycle. In equations (9) to (14), bu, bv, and bw are the offset correction values of each phase stored in the storage unit 22, respectively. Note that each of au_max(ppn), av_max(ppn), aw_max(ppn), au_min(ppn), av_min(ppn), and aw_min(ppn) is a correction value for each pole pair. Therefore, the number of positive gain correction values is 12 (=3 phases×4 pole pairs). Similarly, the number of negative gain correction values is twelve.　

After executing the second correction process, the processing unit 21 in the basic patent method performs linearization of part of the sensor signal (divided signal) corresponding to each segment with respect to the sensor signals Hiu1, Hiv1, and Hiw1. A third correction process is executed. In FIG. 3, for example, if the segment corresponding to the 0th section is the 0th segment, the divided signal corresponding to the 0th segment is the portion of the U-phase sensor signal Hu that connects the zero cross point P1 and the intersection point P2. is a signal of Similarly, in FIG. 3, if the segment corresponding to the No. 1 section is the No. 1 segment, the divided signal corresponding to the No. 1 segment is the intersection point P2 and the zero cross point P3 of the W-phase sensor signal Hw. This is the signal of the part connecting　

The processing unit 21 performs third correction processing for changing the scale of each sensor signal by using values pre-stored in the storage unit 22 as coefficients for the sensor signals Hiu1, Hiv1, and Hiw1. By performing the third correction process, the substantially S-shaped shape of the divided signal corresponding to each segment can be linearized. Here, the values stored in the storage unit 22 are values designed in advance. In this third correction process, a calculation process is performed using a correction formula such as a quadratic function, a cubic function, or a trigonometric function using values designed in advance.　

As an example, the processing unit 21 performs the third correction process on the sensor signals Hiu1, Hiv1, and Hiw1 based on the following formulas (15) to (17). In the following formulas (15) to (17), a and b are coefficients pre-stored in the storage unit 22 .



Hiu2=b×tan(a×Hiu1) (15)



Hiv2=b×tan(a×Hiv1) (16)



Hiw2=b×tan(a×Hiw1) (17)

In equation (15), Hiu2 is the digital value of the U-phase sensor signal obtained by performing the third correction process on the U-phase sensor signal Hiu1. In equation (16), Hiv2 is the digital value of the V-phase sensor signal obtained by performing the third correction process on the V-phase sensor signal Hiv1. In equation (17), Hiw2 is the digital value of the W-phase sensor signal obtained by performing the third correction process on the W-phase sensor signal Hiw1. FIG. 7 is a diagram showing an example of waveforms of sensor signals Hiu2, Hiv2, and Hiw2 obtained after execution of the third correction process. In FIG. 7, the vertical axis indicates digital values, and the horizontal axis indicates electrical angles.　

As described above, in the basic patent method, the common-mode noise included in the sensor signals Hu, Hv, and Hw can be reduced by the first correction processing. Further, in the basic patented method, the mutual variation of each sensor signal can be corrected by the second correction process. Here, the mutual variation is, for example, variation in the amplitude value and offset component of each sensor signal. Furthermore, in the basic patented method, the curve portion (divided signal) of the waveform of each sensor signal can be linearized by the third correction process. In particular, since the length of the curve portion of the sensor signal corresponding to the segment is made uniform by performing the second correction processing, it is easy to apply uniform calculation processing to all divided signals in the third correction processing. . Therefore, by performing the second correction process before the third correction process, the curved portion (divided signal) of the waveform can be further linearized. As a result, in the basic patented method, the divided signal necessary for calculating the mechanical angle estimated value θ based on the above equation (1) becomes more linear, and the difference between the mechanical angle estimated value θ and the mechanical angle true value can be reduced. Therefore, highly accurate mechanical angle estimation can be performed.　

As described above, in the basic patent method, the common-mode noise included in each of the sensor signals Hu, Hv, and Hw can be reduced by the first correction processing. However, ideally, the sensor signals Hiu0, Hiv0, and Hiw0 obtained after the first correction process have a phase difference of 120 electrical degrees from each other. ) is used to reduce common-mode noise, the phase difference between the sensor signals Hiu0, Hiv0, and Hiw0 may not be exactly 120 degrees. Further, in the basic patented method, the curve portion of the waveform of each sensor signal can be linearized by the third correction processing. However, in the third correction process, the calculations represented by the above equations (15), (16) and (17) are performed using table data, but the same table is used for all curve portions (divided signals). Since data is used, an error may occur depending on the position of the divided signal.　

The present invention is capable of further reducing the angle error between the mechanical angle estimated value θ and the mechanical angle true value as compared with the basic patented method described above, thereby improving the mechanical angle detection accuracy of the rotating shaft. aim.　

Three-phase signal generation processing executed by the processing unit 21 of the three-phase signal generation device 1 according to the present embodiment will be described below in order to solve the above technical problem.　

FIG. 8 is a flowchart showing three-phase signal generation processing executed by the processing unit 21 of the three-phase signal generation device 1 according to this embodiment. The processing unit 21 executes the three-phase signal generation process shown in FIG. 8 before executing the learning process of the basic patented method described above. More specifically, the processing unit 21 executes the three-phase signal generation process before executing the third correction process without executing the first correction process and the second correction process.　

As shown in FIG. 8, the processing unit 21 calculates the instantaneous values ( digital value) is acquired (step S1). This step S1 corresponds to the first step, and the process executed in step S1 corresponds to the first process. Hereinafter, the instantaneous value of the U-phase sensor signal Hu is represented by Hu0(t), the instantaneous value of the V-phase sensor signal Hv is represented by Hv0(t), and the instantaneous value of the W-phase sensor signal Hw is represented by Hw0(t). .　

Subsequently, based on the instantaneous value Hu0(t) of the U-phase sensor signal Hu, the instantaneous value Hv0(t) of the V-phase sensor signal Hv, and the instantaneous value Hw0(t) of the W-phase sensor signal Hw, the processing unit 21 , a U-phase complex vector (first complex vector) that is a complex vector of the U-phase sensor signal Hu, a V-phase complex vector (second complex vector) that is a complex vector of the V-phase sensor signal Hv, and a W-phase sensor signal Hw A W-phase complex vector (third complex vector), which is a complex vector of , is calculated (step S2). This step S2 corresponds to the second step, and the process executed in step S2 corresponds to the second process. Hereinafter, the U-phase complex vector is represented by Hu1(t), the V-phase complex vector by Hv1(t), and the W-phase complex vector by Hw1(t).　

FIG. 9 shows the instantaneous value Hu0(t) of the U-phase sensor signal Hu, the instantaneous value Hv0(t) of the V-phase sensor signal Hv, the instantaneous value Hw0(t) of the W-phase sensor signal Hw, and the U-phase complex vector FIG. 4 is a diagram showing Hu1(t), V-phase complex vector Hv1(t), and W-phase complex vector Hw1(t) as vectors on the complex number plane. In FIG. 9, the horizontal axis is the real number axis and the vertical axis is the imaginary number axis. The U-phase complex vector Hu1(t), the V-phase complex vector Hv1(t), and the W-phase complex vector Hw1(t) are vectors that rotate in the directions of the arrows on the complex number plane at an angular velocity ω(t). The instantaneous value Hu0(t) of the U-phase sensor signal Hu, the instantaneous value Hv0(t) of the V-phase sensor signal Hv, and the instantaneous value Hw0(t) of the W-phase sensor signal Hw are absolute values ( It is a vector whose norm) and sign (direction of the vector) change.　

Although not shown in FIG. 9, the instantaneous value Hu0(t) of the U-phase sensor signal Hu, the instantaneous value Hv0(t) of the V-phase sensor signal Hv, and the instantaneous value Hw0(t) of the W-phase sensor signal Hw ) are each represented by a composite vector of the fundamental wave signal and the in-phase signal. In-phase signals are noise signals including DC signals, third harmonic signals, and the like.　

The U-phase complex vector Hu1(t) is expressed by the following arithmetic expression (18) using the matrix A.　

Using the matrix A, the V-phase complex vector Hv1(t) is represented by the following arithmetic expression (19).　

The W-phase complex vector Hw1(t) is represented by the following arithmetic expression (20) using the matrix A.　

Matrix A is represented by the following arithmetic expression (21).　

That is, in step S2, the processing unit 21 calculates the U-phase complex vector Hu1(t), the V-phase complex vector Hv1(t), and the W-phase Calculate the complex vector Hw1(t).　

Subsequently, as shown in FIG. 10, the processing unit 21 generates a triangle 31 whose side is a straight line connecting the vertices of the U-phase complex vector Hu1(t) and the V-phase complex vector Hv1(t) on the complex number plane. and the vertex of the W-phase complex vector Hw1(t) is calculated as a first straight line Htop_uvt_w(t) (step S3). This step S3 corresponds to the third step, and the process executed in step S3 corresponds to the third process. The triangle 31 having one side of a straight line connecting the vertex of the U-phase complex vector Hu1(t) and the vertex of the V-phase complex vector Hv1(t) may be an equilateral triangle or an isosceles triangle.　

Further, as shown in FIG. 10, the processing unit 21 forms a triangle 32 whose side is a straight line connecting the vertex of the V-phase complex vector Hv1(t) and the vertex of the W-phase complex vector Hw1(t) on the complex number plane. A straight line connecting the vertex and the vertex of the U-phase complex vector Hu1(t) is calculated as a second straight line Htop_vwt_u(t) (step S4). This step S4 corresponds to the fourth step, and the process executed in step S4 corresponds to the fourth process. The triangle 32 having a straight line connecting the vertex of the V-phase complex vector Hv1(t) and the vertex of the W-phase complex vector Hw1(t) as one side may be an equilateral triangle or an isosceles triangle.　

Further, as shown in FIG. 10, the processing unit 21 sets the vertex of a triangle 33 having a straight line connecting the vertex of the W-phase complex vector Hw1(t) and the vertex of the U-phase complex vector Hu1(t) as one side, and the vertex of the V A straight line connecting the vertices of the phase complex vector Hv1(t) is calculated as a third straight line Htop_wut_v(t) (step S5). This step S5 corresponds to the fifth step, and the process executed in step S5 corresponds to the fifth process. The triangle 33 having one side of a straight line connecting the vertex of the W-phase complex vector Hw1(t) and the vertex of the U-phase complex vector Hu1(t) may be an equilateral triangle or an isosceles triangle.　

Specifically, the processing unit 21 calculates the first straight line Htop_uvt_w(t) based on the following arithmetic expression (25) in step S3, and calculates the second straight line Htop_vwt_u(t) based on the following arithmetic expression (26) in step S4. t) is calculated, and in step S5, the third straight line Htop_wut_v(t) is calculated based on the following arithmetic expression (27).　

Subsequently, the processing unit 21 calculates the intersection F(t) of the first straight line Htop_uvt_w(t), the second straight line Htop_vwt_u(t) and the third straight line Htop_wut_v(t) (step S6). This step S6 corresponds to the sixth step, and the process executed in step S6 corresponds to the sixth process. As shown in FIG. 10, the intersection F(t) of the first straight line Htop_uvt_w(t), the second straight line Htop_vwt_u(t) and the third straight line Htop_wut_v(t) is different from the origin P0 of the complex number plane. Specifically, the processing unit 21 calculates the intersection point F(t) based on the following arithmetic expressions (28) to (31) in step S6.　

Then, as shown in FIG. 11, the processing unit 21 converts the intersection point F(t) to the origin P0 of the complex number plane, so that the U-phase complex vector Hu1(t), the V-phase complex vector Hv1(t) and W The phase complex vector Hw1(t) is corrected (step S7). This step S7 corresponds to the seventh step, and the process executed in step S7 corresponds to the seventh process. Specifically, in step S7, the processing unit 21 calculates the U-phase complex vector Hu1(t), the V-phase complex vector Hv1(t), and the W-phase complex vector Hw1 based on the following arithmetic expressions (32) to (34). Correct (t). In FIG. 11 and the following arithmetic expressions (32) to (34), Hu2(t) is the corrected U-phase complex vector, Hv2(t) is the corrected V-phase complex vector, and Hw2(t) is the corrected W.
Represents a phase complex vector.

In FIG. 12, the upper graph shows the instantaneous value Hu0(t) of the U-phase sensor signal Hu, the instantaneous value Hv0(t) of the V-phase sensor signal Hv, and the instantaneous value Hw0(t) of the W-phase sensor signal Hw. shows an example of the waveform for one cycle of the electrical angle of . In FIG. 12, the middle graph shows the electrical angle between the real part of the U-phase complex vector Hu1(t), the real part of the V-phase complex vector Hv1(t), and the real part of the W-phase complex vector Hw1(t). An example of a waveform for one cycle is shown. In FIG. 12, the lower graph shows the electrical angle between the imaginary part of the U-phase complex vector Hu1(t), the imaginary part of the V-phase complex vector Hv1(t), and the imaginary part of the W-phase complex vector Hw1(t). An example of a waveform for one cycle is shown.　

In FIG. 13, the upper graph shows the respective norms of the U-phase complex vector Hu2(t), the V-phase complex vector Hv2(t), and the W-phase complex vector Hw2(t) obtained after execution of the correction process in step S7. indicates In FIG. 13, the graphs in the middle row show the polarizations of the U-phase complex vector Hu2(t), the V-phase complex vector Hv2(t), and the W-phase complex vector Hw2(t) obtained after the correction processing in step S7 is performed. Show the corners. In FIG. 13, the lower graph shows the phase difference θuv between the U-phase complex vector Hu2(t) and the V-phase complex vector Hv2(t), the V-phase complex vector Hv2(t) and the W-phase complex vector Hw2(t). and the phase difference θwu between the W-phase complex vector Hw2(t) and the U-phase complex vector Hu2(t).　

As shown in FIG. 13, the norms of the U-phase complex vector Hu2(t), the V-phase complex vector Hv2(t), and the W-phase complex vector Hw2(t) are the same. Also, the phase difference θuv between the U-phase complex vector Hu2(t) and the V-phase complex vector Hv2(t), the phase difference θvw between the V-phase complex vector Hv2(t) and the W-phase complex vector Hw2(t), The phase difference θwu between the W-phase complex vector Hw2(t) and the U-phase complex vector Hu2(t) is 120 electrical degrees.　

By executing the three-phase signal generation processing in this way, three-phase signals (U-phase complex vector Hu2(t), V-phase complex vector Hv2( t), and the W-phase complex vector Hw2(t)). Also, the U-phase complex vector Hu2(t), the V-phase complex vector Hv2(t), and the W-phase complex vector Hw2(t) are signals from which the in-phase signal has been removed, and the amplitude value and offset component variation are , etc. are corrected for mutual variations. That is, by executing the three-phase signal generation process, correction processes equivalent to the first correction process and the second correction process can be performed, and a three-phase signal having an accurate phase difference of 120 degrees can be obtained. be able to.　

After the processing unit 21 obtains the U-phase complex vector Hu2(t), the V-phase complex vector Hv2(t), and the W-phase complex vector Hw2(t) by executing the three-phase signal generation process, A third correction process is performed on these three-phase signals having a phase difference of exactly 120 degrees. In this case, even if the third correction process is performed using the same table data for all curve portions (divided signals) included in the three-phase signal, it is possible to reduce the error caused by the positions of the divided signals. can.　

After performing the third correction process on the U-phase complex vector Hu2(t), the V-phase complex vector Hv2(t), and the W-phase complex vector Hw2(t), the processing unit 21 learns the basic patent method. By executing the processing, the correspondence between the pole pair number, the section number, and the segment number, the feature data of each section, and the mechanical angle estimation formula of each segment are acquired, and these acquired data are used as learning data. It is stored in the storage unit 22 .　

It should be noted that the angle estimation processing executed as online processing by the processing unit 21 in the present embodiment is basically the same as the angle estimation processing of the basic patent method. However, when executing the angle estimation process, the processing unit 21 in the present embodiment executes the three-phase signal generation process to generate the U-phase complex vector Hu2(t) and the V-phase complex vector Hv2(t). , and W-phase complex vector Hw2(t), and identify the current section number and pole pair number based on these three-phase signals.　

As described above, according to the present embodiment, three-phase signals (U-phase complex vector Hu2(t), V-phase complex vector Hv2(t), and W-phase complex vector Hw2(t)). Therefore, according to the present embodiment, compared with the basic patent method disclosed in Japanese Patent No. 6233532, the angle error between the mechanical angle estimated value θ and the mechanical angle true value can be further reduced, thereby improvement in mechanical angle detection accuracy can be realized. Further, according to this embodiment, by converting the three-phase sensor signal from an instantaneous value (real number) to a complex vector, a geometrical approach (vector rotation, translation, etc.) becomes possible, and a signal such as a filter Calculations can be easily performed on the complex number plane without using elements that introduce delays.　

(Modification) The present invention is not limited to the above embodiments, and the configurations described in this specification can be appropriately combined within a mutually consistent range. For example, in the above embodiment, the combination of the motor 100 and the three-phase signal generator 1 was exemplified, but the present invention is not limited to this form, and the sensor magnet attached to the rotating shaft and the three-phase signal generator are combined. A combination is also possible.　

For example, in the above-described embodiment, the first magnetic sensor 11, the second magnetic sensor 12, and the third magnetic sensor 13 are arranged facing the disk-shaped sensor magnet 120 in the axial direction of the rotor shaft 110. is exemplified, the present invention is not limited to this form. For example, when a ring-shaped magnet is used instead of a disc-shaped sensor magnet, the magnetic flux flows in the radial direction of the ring-shaped magnet. and the third magnetic sensor 13 may be arranged facing the ring-shaped magnet.　

For example, in the above embodiment, the sensor magnet 120 attached to the rotor shaft 110 of the motor 100 is used as the rotating magnet. good too. The rotor magnet is also a magnet that rotates in synchronization with the rotor shaft 110 and has a plurality of magnetic pole pairs.　

In the above embodiment, the sensor group 10 includes three magnetic sensors 11, 12 and 13. good. Further, in the above embodiment, the sensor magnet 120 has four magnetic pole pairs, but the number of pole pairs of the sensor magnet 120 is not limited to four. Similarly, when a rotor magnet is used as a magnet for position detection, the number of pole pairs of the rotor magnet is not limited to four.

DESCRIPTION OF SYMBOLS 1... Three-phase signal generation apparatus, 10... Sensor group, 11... 1st magnetic sensor, 12... 2nd magnetic sensor, 13... 3rd magnetic sensor, 20... Signal processing part, 21... Processing part, 22... Storage part, 100... Motor, 110... Rotor shaft, 120... Sensor magnet

Claims (10)

1. a first magnetic sensor facing the rotating magnet and outputting a first signal indicating magnetic field strength;
   
   
   
   a second magnetic sensor that faces the magnet and outputs a second signal having a phase delay of 120° in electrical angle with respect to the first signal;
   
   
   
   a third magnetic sensor that faces the magnet and outputs a third signal having a phase delay of 120 degrees in electrical angle with respect to the second signal;
   
   
   
   a signal processing unit that processes the first signal, the second signal, and the third signal;
   
   
   
   The signal processing unit is
   
   
   
   A first process of obtaining an instantaneous value of the first signal, an instantaneous value of the second signal, and an instantaneous value of the third signal by digitally converting the first signal, the second signal, and the third signal. and,
   
   
   
   Based on the instantaneous value of the first signal, the instantaneous value of the second signal, and the instantaneous value of the third signal, a first complex vector that is a complex vector of the first signal and a complex vector of the second signal a second process of calculating a certain second complex vector and a third complex vector that is the complex vector of the third signal;
   
   
   
   In the complex number plane, a straight line connecting the vertex of the third complex vector and the vertex of a triangle having as one side a straight line connecting the vertex of the first complex vector and the vertex of the second complex vector is calculated as a first straight line. a third process;
   
   
   
   A straight line connecting the vertices of the first complex vector and the vertices of a triangle having as one side a straight line connecting the vertices of the second complex vector and the vertices of the third complex vector in the complex number plane is calculated as a second straight line. a fourth process to
   
   
   
   In the complex number plane, a straight line connecting the vertices of a triangle having one side of a straight line connecting the vertices of the third complex vector and the vertices of the first complex vector and the vertices of the second complex vector is calculated as a third straight line. a fifth process to
   
   
   
   a sixth process of calculating an intersection of the first straight line, the second straight line, and the third straight line;
   
   
   
   and a seventh process of correcting the first, second and third complex vectors by transforming the intersection point to the origin of the complex plane.
2. The signal processing unit calculates the first complex vector, the second complex vector and the third complex vector based on the arithmetic expressions (22), (23) and (24) in the second processing,
   
   
   
   Hu0(t) is the instantaneous value of the first signal, Hv0(t) is the instantaneous value of the second signal, Hw0(t) is the instantaneous value of the third signal, Hu1(t) is the first complex vector, 2. The three-phase signal generator of claim 1, wherein Hv1(t) is the second complex vector and Hw1(t) is the third complex vector.
   

   
3. The signal processing unit calculates the first straight line based on the arithmetic expression (25) in the third process, calculates the second straight line based on the arithmetic expression (26) in the fourth process, and calculates the second straight line based on the arithmetic expression (26) in the fourth process. 5 Calculate the third straight line based on the arithmetic expression (27) in the process,
   
   
   
   3. The three-phase signal generator of claim 2, wherein Htop_uvt_w(t) is the first straight line, Htop_vwt_u(t) is the second straight line, and Htop_wut_v(t) is the third straight line.
   

   
4. The signal processing unit calculates the intersection based on the arithmetic expressions (28) to (31) in the sixth process,
   
   
   
   4. The three-phase signal generator of claim 3, wherein F(t) is the intersection point.
   

   
5. The signal processing unit corrects the first complex vector, the second complex vector and the third complex vector based on the arithmetic expressions (32) to (34) in the seventh processing,
   
   
   
   5. The three-phase signal of claim 4, wherein Hu2(t) is the corrected first complex vector, Hv2(t) is the corrected second complex vector, and Hw2(t) is the corrected third complex vector. generator.
   

   
6. a first magnetic sensor facing the rotating magnet and outputting a first signal indicating magnetic field strength;
   
   
   
   a second magnetic sensor that faces the magnet and outputs a second signal having a phase delay of 120° in electrical angle with respect to the first signal;
   
   
   
   A three-phase signal generation method using a third magnetic sensor that faces the magnet and outputs a third signal having a phase delay of 120 degrees in electrical angle with respect to the second signal,
   
   
   
   a first step of obtaining an instantaneous value of the first signal, an instantaneous value of the second signal, and an instantaneous value of the third signal by digitally converting the first signal, the second signal, and the third signal; and,
   
   
   
   Based on the instantaneous value of the first signal, the instantaneous value of the second signal, and the instantaneous value of the third signal, a first complex vector that is a complex vector of the first signal and a complex vector of the second signal a second step of calculating a second complex vector and a third complex vector that is the complex vector of the third signal;
   
   
   
   In the complex number plane, a straight line connecting the vertex of the third complex vector and the vertex of a triangle having as one side a straight line connecting the vertex of the first complex vector and the vertex of the second complex vector is calculated as a first straight line. a third step;
   
   
   
   In the complex number plane, a straight line connecting the vertices of the first complex vector and the vertices of a triangle having as one side a straight line connecting the vertices of the second complex vector and the vertices of the third complex vector is calculated as a second straight line. a fourth step to
   
   
   
   In the complex number plane, a straight line connecting the vertices of a triangle having one side of a straight line connecting the vertices of the third complex vector and the vertices of the first complex vector and the vertices of the second complex vector is calculated as a third straight line. a fifth step to
   
   
   
   a sixth step of calculating an intersection of the first straight line, the second straight line and the third straight line;
   
   
   
   and a seventh step of correcting the first, second and third complex vectors by transforming the intersection point to the origin of the complex plane.
7. In the second step, calculating the first complex vector, the second complex vector and the third complex vector based on the arithmetic expressions (22), (23) and (24);
   
   
   
   Hu0(t) is the instantaneous value of the first signal, Hv0(t) is the instantaneous value of the second signal, Hw0(t) is the instantaneous value of the third signal, Hu1(t) is the first complex vector, 7. The method of claim 6, wherein Hv1(t) is the second complex vector and Hw1(t) is the third complex vector.
   

   
8. In the third step, the first straight line is calculated based on the arithmetic expression (25); in the fourth step, the second straight line is calculated based on the arithmetic expression (26); and in the fifth step, the arithmetic expression ( 27) to calculate the third straight line based on
   
   
   
   8. The method of claim 7, wherein Htop_uvt_w(t) is the first straight line, Htop_vwt_u(t) is the second straight line, and Htop_wut_v(t) is the third straight line.
   

   
9. In the sixth step, calculating the intersection based on the arithmetic expressions (28) to (31),
   
   
   
   9. The three-phase signal generation method of claim 8, wherein F(t) is the intersection point.
   

   
10. In the seventh step, correcting the first complex vector, the second complex vector and the third complex vector based on arithmetic expressions (32) to (34);
    
    
    
    10. The three-phase signal of claim 9, wherein Hu2(t) is the corrected first complex vector, Hv2(t) is the corrected second complex vector, and Hw2(t) is the corrected third complex vector. generation method.
    

    

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