Signal generation device and signal generation method

Abstract

A signal generation device according to one embodiment of the present invention is provided with: N sensors that output N-phase signals (N is a multiple of 3) on the basis of the rotation angle of a rotating body; and a signal processing unit that corrects an N-phase signal on the basis of an arithmetic expression (10) in which Hi is an i-th phase signal (i is an integer of 1 to N), Hi'is the corrected i-th phase signal, HiP-P is the difference between the maximum value Himax and the minimum value Himin of the i-th phase signal, Hiofs is the offset of the i-th phase signal, HiP-PL is the learning value of the difference HiP-P, and HiofsL is the learning value of the offset Hiofs: [numerical expression 1] # imgabs0 #

Description

Technical Field

[0001] The invention relates to a signal generating device and a signal generating method.

[0002] This application is based on Japanese Patent Application No. 2022-106315 filed on June 30, 2022. The present application claims the priority of the aforementioned application. The entire contents of the application are incorporated herein by reference. Background Art

[0003] Conventionally, as a motor capable of accurately controlling the rotational position, there is a known structure having an absolute angular position sensor such as an optical encoder or a resolver. However, the absolute angular position sensor is large and expensive. Therefore, Patent Document 1 discloses a position estimation method that estimates the rotational position of a motor using three inexpensive and small magnetic sensors instead of using an absolute angular position sensor.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 6233532 Summary of the invention

[0007] Problems to be solved by the invention

[0008] In the position estimation method described in Patent Document 1, the mechanical angle of the rotating body can be estimated with high accuracy using three inexpensive and small magnetic sensors, but higher accuracy is sometimes required in the market.

[0009] Means for solving problems

[0010] One embodiment of the signal generating device of the present invention comprises: N sensors that output N-phase signals (N is a multiple of 3) according to the rotation angle of the rotating body; and a signal processing unit that corrects the N-phase signals based on the calculation formula (10), in which H i is the i-th phase signal (i is an integer from 1 to N), H i ' is the corrected i-th phase signal, H iP-P is the maximum value H of the i-th phase signal imax With the minimum value H imin The difference, H iofs is the offset of the i-th phase signal, H iP-PL is the differential H iP-P The learning value, H iofsL is the offset H iofs learning value.

[0011] [Formula 1]

[0012]

[0013] One embodiment of the signal generation method of the present invention is a signal generation method using N sensors (N is a multiple of 3) that output N-phase signals according to the rotation angle of a rotating body, the signal generation method including the step of correcting the N-phase signals based on the calculation formula (10), in which H i is the i-th phase signal (i is an integer from 1 to N), H i ' is the corrected i-th phase signal, H iP-P is the maximum value H of the i-th phase signal imax With the minimum value H imin The difference, H iofs is the offset of the i-th phase signal, H iP-PL is the differential H iP-P The learning value, H iofsL is the offset H iofs learning value.

[0014] [Formula 2]

[0015]

[0016] Effects of the Invention

[0017] According to the above aspect of the present invention, there are provided a signal generating device and a signal generating method capable of improving the estimation accuracy of the mechanical angle (rotation angle) of a rotating body. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a block diagram schematically showing the configuration of a signal generating device 1 according to an embodiment of the present invention.

[0019] Figure 2 2 is a diagram showing an example of the waveforms of the U-phase signal Hu, the V-phase signal Hv, and the W-phase signal Hw.

[0020] Figure 3 yes Figure 2 FIG. 1 is an enlarged view of the U-phase signal Hu, the V-phase signal Hv, and the W-phase signal Hw included in one pole pair region.

[0021] Figure 4 : is a flowchart showing the learning process executed by the processing unit 21 of the signal generating device 1 in the present embodiment.

[0022] Figure 5 is the i-th phase learning signal H iL A diagram showing an example of a waveform.

[0023] Figure 61 is a flowchart showing the first angle estimation process executed by the processing unit 21 of the signal generating device 1 according to the present embodiment.

[0024] Figure 7 is the i-th phase signal H i FIG. 1 is a diagram of a first example of a waveform.

[0025] Figure 8 : is a flowchart showing the second angle estimation process executed by the processing unit 21 of the signal generating device 1 according to the present embodiment.

[0026] Fig. 9 is the i-th phase signal H i FIG. 2 is a diagram of a second example of a waveform.

[0027] Fig.10 Yes Fig. 9 The i-th phase signal H shown i The i-th phase signal H included in the period from time t30 to time t32 in the waveform of i The enlarged diagram of the waveform. DETAILED DESCRIPTION

[0028] Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

[0029] Figure 1 1 is a block diagram schematically showing the structure of a signal generating device 1 according to an embodiment of the present invention. Figure 1 As shown, the signal generating device 1 is a device for detecting the mechanical angle (rotation angle) of the rotor shaft 110 as the rotating shaft of the motor 100. In the present embodiment, the motor 100 is, for example, an inner rotor type three-phase brushless DC motor. The motor 100 has the rotor shaft 110 (rotating body) and the sensor magnet 120.

[0030] The sensor magnet 120 is a disk-shaped magnet mounted on the rotor shaft 110. The sensor magnet 120 rotates synchronously with the rotor shaft 110. The sensor magnet 120 has P (P is an integer greater than 1) magnetic pole pairs. In the present embodiment, as an example, the sensor magnet 120 has 4 magnetic pole pairs. In addition, the magnetic pole pair refers to a pair of N poles and S poles. That is, in the present embodiment, the sensor magnet 120 has 4 pairs of N poles and S poles, and has a total of 8 magnetic poles.

[0031] The signal generating device 1 includes a sensor group 10 and a signal processing unit 20. Figure 1 Although not shown in the figure, a circuit substrate is mounted on the motor 100, and the sensor group 10 and the signal processing unit 20 are arranged on the circuit substrate. The sensor magnet 120 is arranged at a position that does not interfere with the circuit substrate. The sensor magnet 120 can be arranged inside the housing of the motor 100, or can be arranged outside the housing.

[0032] The sensor group 10 includes N sensors that output N-phase signals (N is a multiple of 3) according to the mechanical angle of the rotor shaft 110. In the present embodiment, since N is 3, the sensor group 10 includes three sensors that output three-phase signals according to the mechanical angle of the rotor shaft 110. Specifically, the sensor group 10 includes a first magnetic sensor 11, a second magnetic sensor 12, and a third magnetic sensor 13. For example, the first magnetic sensor 11, the second magnetic sensor 12, and the third magnetic sensor 13 are arranged on the circuit board in a state opposite to the sensor magnet 120.

[0033] In the present 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 degrees along the rotation direction of the sensor magnet 120. 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 a magnetoresistive element such as a Hall element or a linear Hall IC. The first magnetic sensor 11, the second magnetic sensor 12, and the third magnetic sensor 13 each output an analog signal representing the magnetic field strength that changes according to the rotation position of the rotor shaft 110, that is, the rotation position of the sensor magnet 120.

[0034] 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 is equivalent to 1 / P of one cycle of the mechanical angle. In the present 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 is equivalent to 1 / 4 of one cycle of the mechanical angle, that is, a mechanical angle of 90 degrees. The analog signal output from the second magnetic sensor 12 has a phase delay of 120 degrees of electrical angle relative to the analog signal output from the first magnetic sensor 11. The analog signal output from the third magnetic sensor 13 has a phase delay of 120 degrees of electrical angle relative to the analog signal output from the second magnetic sensor 12.

[0035] Hereinafter, the analog signal output from the first magnetic sensor 11 is referred to as a U-phase signal Hu, the analog signal output from the second magnetic sensor 12 is referred to as a V-phase signal Hv, and the analog signal output from the third magnetic sensor 13 is referred to as a W-phase signal Hw. The U-phase signal Hu output from the first magnetic sensor 11, the V-phase signal Hv output from the second magnetic sensor 12, and the W-phase signal Hw output from the third magnetic sensor 13 are respectively input to the signal processing unit 20.

[0036] The signal processing unit 20 is a signal processing circuit that processes the U-phase signal Hu, the V-phase signal Hv, and the W-phase signal Hw. The signal processing unit 20 estimates the mechanical angle of the rotor shaft 110 as a rotating body based on the U-phase signal Hu, the V-phase signal Hv, and the W-phase signal Hw. The signal processing unit 20 includes a processing unit 21 and a memory 22.

[0037] The processing unit 21 is, for example, a microprocessor such as an MCU (Microcontroller Unit). The U-phase signal Hu, the V-phase signal Hv, and the W-phase signal Hw are respectively input to the processing unit 21. The processing unit 21 is communicatively connected to the memory 22 via a communication bus not shown. The processing unit 21 performs at least the following two processes according to a program pre-stored in the memory 22.

[0038] As an off-line process, the processing unit 21 performs a learning process for acquiring learning data necessary for estimating the mechanical angle of the rotor shaft 110 based on the U-phase signal Hu, the V-phase signal Hv, and the W-phase signal Hw. Off-line processing refers to processing performed before the signal generating device 1 is shipped from a manufacturing factory or before the signal generating device 1 is assembled into a customer's system and actually used.

[0039] In addition, as an online process, the processing unit 21 performs an angle estimation process for estimating the mechanical angle of the rotor shaft 110 based on the U-phase signal Hu, the V-phase signal Hv, and the W-phase signal Hw and the learning data obtained by the learning process. The online process refers to the process performed when the signal generating device 1 is assembled into a system on the customer side and actually used.

[0040] The memory 22 includes: a non-volatile memory that stores programs, various setting data, and the above-mentioned learning data required for the processing unit 21 to execute various processes; and a volatile memory that is used as a temporary storage destination for data when the processing unit 21 executes various processes. The non-volatile memory is, for example, an EEPROM (Electrically Erasable Programmable Read-Only Memory) or a flash memory. The volatile memory is, for example, a RAM (Random Access Memory).

[0041] Before explaining the learning process and angle estimation process performed by the processing unit 21 of the signal generating device 1 configured as described above, the position estimation method disclosed in Japanese Patent No. 6233532 will be briefly explained for easy understanding of the present invention. In the following description, the position estimation method disclosed in Japanese Patent No. 6233532 is sometimes referred to as the basic patent method. For details of the basic patent method, refer to Japanese Patent No. 6233532. In addition, for the sake of convenience, the following uses Figure 1 The elements shown describe the basic patented method.

[0042] First, the learning process performed by the processing unit 21 in the basic patent method will be described.

[0043] When the processing unit 21 starts the learning process, the digital values ​​(instantaneous values) of the three-phase signals Hu, Hv, and Hw output from the magnetic sensors 11, 12, and 13 are obtained while the sensor magnet 120 is rotated together with the rotor shaft 110. Specifically, the processing unit 21 has a built-in A / D converter, and the processing unit 21 performs digital conversion on the U-phase signal Hu, the V-phase signal Hv, and the W-phase signal Hw at a predetermined sampling frequency through the A / D converter, thereby obtaining the digital values ​​of the U-phase signal Hu, the V-phase signal Hv, and the W-phase signal Hw.

[0044] When the learning process is executed, the motor 100 may be energized by a motor control device (not shown) to rotate the rotor shaft 110. Alternatively, the rotor shaft 110 may be connected to a rotating machine (not shown) to rotate the rotor shaft 110.

[0045] Figure 2 : is a diagram showing an example of the waveforms of the U-phase signal Hu, the V-phase signal Hv, and the W-phase signal Hw. Figure 2 As shown in the figure, one electrical angle cycle of each of the three-phase signals Hu, Hv and Hw is equivalent to 1 / 4 of one mechanical angle cycle, that is, the mechanical angle is 90 degrees. Figure 2 In the example, the period from time t1 to time t5 is equivalent to one mechanical angle cycle (mechanical angle 360 ​​degrees). Figure 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 correspond to a mechanical angle of 90 degrees. In addition, the three-phase signals Hu, Hv, and Hw have a phase difference of 120 degrees in electrical angle.

[0046] The processing unit 21 extracts the intersection points where two phase signals of the three phase signals intersect each other and the zero crossing points where the three phase signals intersect the reference signal level within one mechanical angle cycle based on the digital values ​​of the three phase signals Hu, Hv and Hw. The reference signal level is, for example, a ground level. When the reference signal level is a ground level, the digital value of the reference signal level is "0".

[0047] like Figure 2 As shown in FIG. 1 , the processing unit 21 divides one cycle of the mechanical angle into four pole pair regions associated with the pole pair numbers based on the extraction result of the zero crossing point. Figure 2 In the table, "No.C" indicates the pole pair number. Figure 1As shown, the four magnetic pole pairs of the sensor magnet 120 are assigned pole pair numbers in advance. For example, the pole pair number "0" is assigned to the magnetic pole pair set in the range of mechanical angle 0 to 90 degrees. The pole pair number "1" is assigned to the magnetic pole pair set in the range of mechanical angle 90 to 180 degrees. The pole pair number "2" is assigned to the magnetic pole pair set in the range of mechanical angle 180 to 270 degrees. The pole pair number "3" is assigned to the magnetic pole pair set in the range of mechanical angle 270 to 360 degrees.

[0048] For example, when the U-phase signal Hu is used as a reference, the processing unit 21 recognizes the zero-crossing point obtained at the sampling timing (time t1) when the mechanical angle is 0 degrees among the zero-crossing points of the U-phase signal Hu as the starting point of the pole pair region associated with the pole pair number "0". In addition, the processing unit 21 recognizes the zero-crossing point obtained at the sampling timing (time t2) when the mechanical angle is 90 degrees among the zero-crossing points of the U-phase signal Hu as the end point of the pole pair region associated with the pole pair number "0". That is, the processing unit 21 determines the interval 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".

[0049] The processing unit 21 also recognizes the zero-crossing point obtained at the sampling timing (time t2) when the mechanical angle is 90 degrees among the zero-crossing points of the U-phase signal Hu as the starting point of the pole pair region associated with the pole pair number "1". In addition, the processing unit 21 recognizes the zero-crossing point obtained at the sampling timing (time t3) when the mechanical angle is 180 degrees among the zero-crossing points of the U-phase signal Hu as the end point of the pole pair region associated with the pole pair number "1". That is, the processing unit 21 determines the interval between the zero-crossing point obtained at time t2 and the zero-crossing point obtained at time t3 as the pole pair region associated with the pole pair number "1".

[0050] The processing unit 21 also recognizes the zero-crossing point obtained at the sampling timing (time t3) when the mechanical angle is 180 degrees among the zero-crossing points of the U-phase signal Hu as the starting point of the pole pair region associated with the pole pair number "2". In addition, the processing unit 21 recognizes the zero-crossing point obtained at the sampling timing (time t4) when the mechanical angle is 270 degrees among the zero-crossing points of the U-phase signal Hu as the end point of the pole pair region associated with the pole pair number "2". That is, the processing unit 21 determines the interval between the zero-crossing point obtained at time t3 and the zero-crossing point obtained at time t4 as the pole pair region associated with the pole pair number "2".

[0051] The processing unit 21 also recognizes the zero-crossing point obtained at the sampling timing (time t4) when the mechanical angle is 270 degrees among the zero-crossing points of the U-phase signal Hu as the starting point of the pole pair region associated with the pole pair number "3". In addition, the processing unit 21 recognizes the zero-crossing point obtained at the sampling timing (time t5) when the mechanical angle is 360 degrees among the zero-crossing points of the U-phase signal Hu as the end point of the pole pair region associated with the pole pair number "3". That is, the processing unit 21 determines the interval between the zero-crossing point obtained at time t4 and the zero-crossing point obtained at time t5 as the pole pair region associated with the pole pair number "3".

[0052] like Figure 2 As shown in FIG. 1 , the processing unit 21 divides the four pole pair regions into 12 sections associated with section numbers based on the extraction results of the intersection points and the zero crossing points. Figure 2 In the example, "No.A" indicates the segment number associated with each segment. Figure 2 As shown, the 12 segments contained in each of the four pole pair regions are associated with segment numbers from "0" to "11".

[0053] Figure 3 yes Figure 2 The enlarged view of the three-phase signals Hu, Hv and Hw contained in one pole pair area is shown. Figure 3 In the case of , the reference value of the amplitude (reference signal level) is "0". Figure 3 In the example, the digital value of the amplitude as a positive value represents the digital value of the magnetic field strength at the N pole. In addition, the digital value of the amplitude as a negative value represents the digital value of the magnetic field strength at the S pole as an example.

[0054] exist Figure 3 In , points P1, P3, P5, P7, P9, P11, and P13 are zero-crossing points extracted from the digital values ​​of the three-phase signals Hu, Hv, and Hw contained in one pole pair region. Figure 3 In FIG. 1 , point P2, point P4, point P6, point P8, point P10, and point P12 are intersection points extracted from the digital values ​​of the three-phase signals Hu, Hv, and Hw included in one pole pair region. Figure 3 As shown, the processing unit 21 determines the interval between the adjacent zero-crossing points and the intersection points as a segment.

[0055] The processing unit 21 determines the section between the zero-crossing point P1 and the intersection point P2 as a section associated with the section number "0". The processing unit 21 determines the section between the intersection point P2 and the zero-crossing point P3 as a section associated with the section number "1". The processing unit 21 determines the section between the zero-crossing point P3 and the intersection point P4 as a section associated with the section number "2". The processing unit 21 determines the section between the intersection point P4 and the zero-crossing point P5 as a section associated with the section number "3". The processing unit 21 determines the section between the zero-crossing point P5 and the intersection point P6 as a section associated with the section number "4". The processing unit 21 determines the section between the intersection point P6 and the zero-crossing point P7 as a section associated with the section number "5".

[0056] The processing unit 21 determines the section between the zero-crossing point P7 and the intersection point P8 as a section associated with the section number "6". The processing unit 21 determines the section between the intersection point P8 and the zero-crossing point P9 as a section associated with the section number "7". The processing unit 21 determines the section between the zero-crossing point P9 and the intersection point P10 as a section associated with the section number "8". The processing unit 21 determines the section between the intersection point P10 and the zero-crossing point P11 as a section associated with the section number "9". The processing unit 21 determines the section between the zero-crossing point P11 and the intersection point P12 as a section associated with the section number "10". The processing unit 21 determines the section between the intersection point P12 and the zero-crossing point P13 as a section associated with the section number "11".

[0057] In addition, in the following description, for example, a segment assigned with segment number "0" is referred to as "segment No. 0", and a segment assigned with segment number "11" is referred to as "segment No. 11".

[0058] like Figure 2 As shown in FIG. 1 , the continuous numbers during the entire period of one mechanical angle cycle are associated with each section number as a segment number. Figure 2 In the example, "No.B" indicates the segment number associated with each segment number. In addition, segment is a term for a straight line connecting adjacent intersections and zero crossings. In other words, a straight line connecting the start and end points of each segment is called a segment. Figure 3 For example, the starting point of the 0th segment is the zero-crossing point P1, and the end point of the 0th segment is the intersection point P2. Therefore, the segment corresponding to the 0th segment is the straight line connecting the zero-crossing point P1 and the intersection point P2. Figure 3 For example, the starting point of the first segment is the intersection point P2, and the end point of the first segment is the zero-crossing point P3. Therefore, the segment corresponding to the first segment is a straight line connecting the intersection point P2 and the zero-crossing point P3.

[0059] like Figure 2As shown, in the pole pair region associated with pole pair number "0", segment numbers "0" to "11" are associated with segment numbers "0" to "11". In the pole pair region associated with pole pair number "1", segment numbers "12" to "23" are associated with segment numbers "0" to "11". In the pole pair region associated with pole pair number "2", segment numbers "24" to "35" are associated with segment numbers "0" to "11". In the pole pair region associated with pole pair number "3", segment numbers "36" to "47" are associated with segment numbers "0" to "11".

[0060] In the following description, for example, a segment to which segment number “0” is assigned is referred to as “segment 0”, and a segment to which segment number “11” is assigned is referred to as “segment 11”.

[0061] 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 an arbitrary point on the segment, and θ is the mechanical angle corresponding to the arbitrary point on the segment. Figure 3 For example, the starting point of the segment corresponding to the 0th segment is the zero crossing point P1, and the end point of the segment corresponding to the 0th segment is the intersection point P2. Figure 3 For example, the starting point of the segment corresponding to the first segment is the intersection point P2, and the end point of the segment corresponding to the first segment is the zero-crossing point P3.

[0062] For example, the linear function θ(Δx) representing the segment is represented by the following formula (1). In the following formula (1), "i" is the segment number, which is an integer from 0 to 47. In the following description, the linear function θ(Δx) represented by the following formula (1) is sometimes referred to as a mechanical angle estimation formula, and the mechanical angle θ calculated by the following formula (1) is sometimes referred to as a mechanical angle estimation value.

[0063] θ(Δx)=k[i]×Δx+θ res[i]…(1)

[0064] In the above formula (1), k[i] is a coefficient called a normalization coefficient. In other words, k[i] is a coefficient representing the slope of the i-th segment. The normalization coefficient k[i] is shown by the following formula (2). In the following formula (2), ΔXnorm[i] is the deviation of the digital value between the start point and the end point of the i-th segment. Figure 3 In , for example, ΔXnorm[i] corresponding to the segment 0 is the deviation of the digital value between the zero crossing point P1 and the intersection point P2. Figure 3 In , for example, ΔXnorm[i] of the segment corresponding to the 1st segment is the deviation of the digital value between the intersection point P2 and the zero crossing point P3.

[0065] k[i]=θnorm[i] / ΔXnorm[i]…(2)

[0066] In the above formula (2), θnorm[i] is the deviation of the mechanical angle between the start and end of the i-th segment, which is shown by the following formula (3). In the following formula (3), t[i] is the time between the start and end of the i-th segment, t[0] is the time between the start and end of the 0th segment, and t

[47] is the time between the start and end of the 47th segment. Figure 3 In, for example, when the segment corresponding to the 0th section is the 0th section, t[0] is the time between the zero-crossing point P1 and the intersection point P2.

[0067] θnorm[i]={t[i] / (t[0]+…+t

[47] )}×360

[0068] [degM]

[0069] …(3)

[0070] In the above formula (1), θres[i] is a constant called the angle reset value of the i-th segment (the intercept of the linear function θ(Δx)). When the segment number "i" is "0", the angle reset value θres[i] is shown by the following formula (4). When the segment number "i" is any one of "1" to "47", the angle reset value θres[i] is shown by the following formula (5). In addition, instead of calculating θnorm[i] based on t[i] as described above, it is also possible to calculate it based on the mechanical angle true value (for example, the mechanical angle indicated by the output signal of the main encoder installed on the rotor shaft 110).

[0071] θres[i]=0[degM]…(4)

[0072] θres[i]=∑(θnorm[i-1])…(5)

[0073] The processing unit 21 performs the learning process as described above to obtain the correspondence between the pole pair number, the segment number, the segment number, the characteristic data of each segment, and the mechanical angle estimation formula of each segment, and stores the obtained data as learning data in the memory 22. In addition, the characteristic data of each segment is the magnitude relationship and positive and negative signs of the digital values ​​of the three-phase signals Hu, Hv and Hw included in each segment. In addition, the normalization coefficient k[i] and the angle reset value θres[i] constituting the mechanical angle estimation formula of each segment are stored in the memory 22 as learning data.

[0074] Next, the angle estimation process performed by the processing unit 21 in the basic patent method is described. When the angle estimation process is started, the processing unit 21 obtains the three-phase signals Hu, Hv and Hw output from the magnetic sensors 11, 12 and 13. Specifically, the processing unit 21 performs digital conversion on the U-phase signal Hu, the V-phase signal Hv and the W-phase signal Hw at a predetermined sampling frequency through an A / D converter, thereby obtaining the digital values ​​of the U-phase signal Hu, the V-phase signal Hv and the W-phase signal Hw.

[0075] Then, the processing unit 21 determines the current segment number and pole pair number based on the digital values ​​of the three-phase signals Hu, Hv, and Hw obtained at the current sampling timing. Figure 3 In the example, it is assumed that point PHu located on the waveform of the U-phase signal Hu, point PHv located on the waveform of the V-phase signal Hv, and point PHw located on the waveform of the W-phase signal Hw are the digital values ​​of the three-phase signals Hu, Hv, and Hw obtained at this sampling timing. The processing unit 21 compares the characteristic data such as the size relationship and positive and negative signs of the digital values ​​of point PHu, point PHv, and point PHw with the characteristic data of each segment contained in the learning data stored in the memory 22 to determine the current segment (segment number). Figure 3 In the example of , the 9th segment is determined as the current segment. In addition, in this specification, the method of determining the pole pair number is not described. For the method of determining the pole pair number, refer to Japanese Patent No. 6233532. As the pole pair number of this sampling timing, for example, it is assumed that the pole pair number "2" is determined.

[0076] Then, the processing unit 21 determines the current segment number based on the determined current segment number and pole pair number. For example, the processing unit 21 determines the current segment number by the formula "segment number = 12 × pole pair number + segment number". As described above, it is assumed that the segment number "9" is determined as the current segment number and the pole pair number "2" is determined as the current pole pair number. In this case, the processing unit 21 determines the segment number "33" as the current segment number (see Figure 2 ).

[0077] The processing unit 21 reads the normalization coefficient k[i] and the angle reset value θres[i] corresponding to the determined segment number "i" from the learning data stored in the memory 22, and calculates the mechanical angle estimation value θ by the mechanical angle estimation formula shown in the above formula (1). Here, as Δx substituted into the mechanical angle estimation formula, the digital value of the three-phase signal corresponding to the determined segment is used. For example, as described above, when the segment number "33" is determined as the current segment number, the processing unit 21 reads the normalization coefficient k

[33] and the angle reset value θres

[33] from the memory 22, and converts the digital value of the point PHv (refer to Figure 3) is substituted into the mechanical angle estimation formula as Δx, thereby calculating the mechanical angle estimation value θ at the current sampling timing.

[0078] The above is the basic estimation procedure of the mechanical angle in the basic patent method that is the basis of the present invention. However, the waveforms of the three-phase signals Hu, Hv, and Hw obtained from the sensor group 10 when performing the angle estimation process may sometimes change due to the generation of interference relative to the waveforms obtained when performing the learning process. In this way, when the waveforms of the three-phase signals Hu, Hv, and Hw obtained from the sensor group 10 are different when performing the angle estimation process and when performing the learning process, the learning data obtained by the learning process cannot be properly used when performing the angle estimation process, and the mechanical angle estimation accuracy (the accuracy of the mechanical angle estimation value θ) may be reduced.

[0079] The object of the present invention is to reduce the angle error between the estimated mechanical angle value θ and the true mechanical angle value caused by interference, compared with the above-mentioned basic patent method, thereby improving the mechanical angle estimation accuracy.

[0080] In order to solve the above-mentioned technical problems, the learning process and the angle estimation process performed by the processing unit 21 of the signal generating device 1 in the present embodiment are described below. In addition, in order to distinguish the learning process and the angle estimation process in the present embodiment from the learning process and the angle estimation process in the basic patent method, in the following description, the learning process and the angle estimation process in the basic patent method are referred to as the basic learning process and the basic angle estimation process.

[0081] Figure 4 2 is a flowchart showing the learning process performed by the processing unit 21 of the signal generating device 1 in this embodiment. Figure 4 As shown, the processing unit 21 first performs basic learning processing (step S1). As already described, the processing unit 21 obtains the correspondence between the pole pair number, the segment number, the segment number, the characteristic data of each segment, and the mechanical angle estimation formula of each segment by performing the basic learning processing, and stores the obtained data in the memory 22 as learning data.

[0082] Then, the processing unit 21 obtains the i-th phase signal H based on the digital values ​​of the three-phase signals Hu, Hv, and Hw obtained when the basic learning process is executed. i The peak to peak learning value H iP-PL and offset learning value H iofsL (Step S2). i is an integer from 1 to N (3 in this embodiment). For example, the first phase signal H1 corresponds to the U phase signal Hu. The second phase signal H2 corresponds to the V phase signal Hv. The third phase signal H3 corresponds to the W phase signal Hw.i is called the i-th phase learning signal H iL .

[0083] Figure 5 is the i-th phase learning signal H iL An example of a waveform of Figure 5 As shown, the i-th phase learning signal H iL One electrical angle cycle is equivalent to 90 degrees of mechanical angle. Figure 5 In the example, the period from time t10 to time t14 corresponds to one mechanical angle cycle (mechanical angle 360 ​​degrees). Figure 5 , the period from time t10 to time t11, the period from time t11 to time t12, the period from time t12 to time t13, and the period from time t13 to time t14 correspond to a mechanical angle of 90 degrees, respectively.

[0084] In step S2, the processing unit 21 obtains the i-th phase learning signal H iL The positive side peak point P contained in imaxL The value (digital value) of is taken as the i-th phase learning signal H iL The maximum value H imaxL In addition, the processing unit 21 obtains the i-th phase learning signal H iL The negative side peak point P contained in iminL The value (digital value) of is taken as the i-th phase learning signal H iL The minimum value H iminL Then, the processing unit 21 calculates the i-th phase learning signal H based on the following calculation formula (6): iL Peak-to-peak learning value H iP-PL Thus, the peak-to-peak learning value H iP-PL is the i-th phase learning signal H iL The maximum value H imaxL With the minimum value H iminL The difference between.

[0085] [Formula 3]

[0086] H iP-PL =H imaxL -H iminL …(6)

[0087] Then, in step S2, the processing unit 21 calculates the i-th phase learning signal H based on the following equation (7): iL The offset learning value H iofsL .

[0088] [Formula 4]

[0089]

[0090] In addition, if Figure 5 As shown, the processing unit 21 may use the i-th phase learning signal H obtained in one cycle of the electrical angle from time t11 to time t12. iL The maximum value H imaxL And the minimum value H iminL , calculate the peak-to-peak learning value H iP-PL And the offset learning value H iofsL In addition, the processing unit 21 may also use the i-th phase learning signal H obtained in one cycle of another electrical angle. iL The maximum value H imaxL And the minimum value H iminL , calculate the peak-to-peak learning value H iP-PL and offset learning value H iofsL Alternatively, the processing unit 21 may use the i-th phase learning signal H obtained in one cycle of the mechanical angle. iL The four maximum values ​​of H imaxL The average value and the four minimum values ​​H iminL The average value of the peak-to-peak learning value H is calculated iP-PL and offset learning value H iofsL .

[0091] The processing unit 21 converts the peak-to-peak learning value H obtained by the process of step S2 as described above into iP-PL and offset learning value H iofsL After saving to the memory 22, the Figure 4 In this way, the processing unit 21 performs the learning process, and the memory 22 stores not only the learning data obtained by the basic learning process, but also the i-th phase learning signal H iL Peak-to-peak learning value H iP-PL and offset learning value H iofsL .

[0092] That is, the first phase learning signal H 1L (U-phase signal Hu) peak-to-peak learning value H 1P-PL And the offset learning value H 1ofsL , Phase 2 learning signal H 2L Peak-to-peak learning value H of (V-phase signal Hv) 2P-PL And the offset learning value H 2ofsL , Phase 3 learning signal H 3L Peak-to-peak learning value H of (W-phase signal Hw) 3P-PL And the offset learning value H 3ofsL is stored in the memory 22.

[0093] Figure 61 is a flowchart showing the first angle estimation process executed by the processing unit 21 of the signal generating device 1 according to the present embodiment. The processing unit 21 repeatedly executes the first angle estimation process at a predetermined cycle. Figure 6 The first angle estimation process shown in FIG. Figure 6 As shown, when the processing unit 21 starts the first angle estimation process, it first obtains the digital values ​​of the three-phase signals Hu, Hv, and Hw (step S11).

[0094] Next, the processing unit 21 determines whether the correction start flag is "0" (step S12). The correction start flag is a flag that is reset to "0" when the processing unit 21 is started. When the correction start flag is "0" (step S12: Yes), the processing unit 21 transfers to the processing of step S13. On the other hand, when the correction start flag is not "0" (step S12: No), the processing unit 21 transfers to the processing of step S17. The following first describes the processing performed when the correction start flag is "0".

[0095] When the correction start flag is "0" (step S12: Yes), the processing unit 21 performs basic angle estimation processing based on the digital values ​​of the three-phase signals Hu, Hv, and Hw to calculate the mechanical angle estimation value θ (step S13). Then, the processing unit 21 determines whether the rotor shaft 110 has rotated 90 degrees based on the mechanical angle estimation value θ obtained in the past first angle estimation processing and the mechanical angle estimation value θ obtained in the current first angle estimation processing (step S14).

[0096] When the processing unit 21 determines that the rotor shaft 110 has not rotated 90 degrees (step S14: No), the processing of steps S15 and S16 described later is skipped and the first angle estimation processing of this time is ended. On the other hand, when the processing unit 21 determines that the rotor shaft 110 has rotated 90 degrees (step S14: Yes), the processing unit 21 calculates the i-th phase signal H based on the digital values ​​of the three-phase signals Hu, Hv and Hw obtained during the period when the rotor shaft 110 rotates 90 degrees. i The peak-peak value H iP-P and offset H iofs (Step S15).

[0097] Figure 7 is the i-th phase signal H obtained during the period when the rotor shaft 110 rotates 90 degrees (the period from time t20 to time t21). i An example of the waveform of Figure 7 For convenience, the i-th phase signal H obtained during the period when the rotor shaft 110 rotates from 90 degrees to 360 degrees (from time t21 to time t24) is also shown. i waveform. Figure 7 It also shows Figure 5The i-th phase learning signal H is shown iL waveform.

[0098] like Figure 7 As shown, the i-th phase signal H i One electrical angle cycle is equivalent to 90 degrees of mechanical angle. Figure 7 In the example, the period from time t20 to time t24 corresponds to one mechanical angle cycle (mechanical angle 360 ​​degrees). Figure 7 , the period from time t20 to time t21, the period from time t21 to time t22, the period from time t22 to time t23, and the period from time t23 to time t24 each correspond to a mechanical angle of 90 degrees.

[0099] In step S15, the processing unit 21 obtains the i-th phase signal H obtained during the period from time t20 to time t21. i The positive side peak point P contained in imax The value (digital value) is used as the i-th phase signal H i The maximum value H imax In addition, the processing unit 21 obtains the i-th phase signal H obtained during the period from time t20 to time t21. i The negative side peak point P contained in imin The value (digital value) of i The minimum value H imin Then, the processing unit 21 calculates the i-th phase signal H based on the following calculation formula (8): i The peak-peak value H iP-P Thus, the peak-to-peak value H iP-P is the i-th phase signal H i The maximum value H imax With the minimum value H imin The difference.

[0100] [Formula 5]

[0101] H iP-P =H imax -H imin …(8)

[0102] Then, in step S15, the processing unit 21 calculates the i-th phase signal H according to the following equation (9): i The offset H iofs .

[0103] [Formula 6]

[0104]

[0105] As described above, the i-th phase signal H obtained when the first angle estimation process is executed iThe waveform of the i-th phase learning signal H obtained when the learning process is performed may be different due to the generation of interference. iL For example, when the temperature during the execution of the first angle estimation process is higher than the temperature during the execution of the learning process, Figure 7 As shown, the i-th phase signal H i The peak-peak value H iP-P It is possible to learn the signal H in phase i iL Peak-to-peak learning value H iP-PL In addition, when the temperature when the first angle estimation process is executed is different from the temperature when the learning process is executed, the i-th phase signal H i The offset H iofs It is possible to learn the signal H from the i-th phase iL The offset learning value H iofsL Offset in positive or negative direction.

[0106] The processing unit 21 converts the i-th phase signal H obtained by the above calculation process into i The peak-peak value H iP- P and offset H iofs The peak-to-peak value H of the first phase signal H1 (U-phase signal Hu) is thus 1P-P and offset H 1ofs , the peak-to-peak value H of the second phase signal H2 (V phase signal Hv) 2P-P and offset H 2ofs , and the peak-to-peak value H of the third phase signal H3 (W phase signal Hw) 3P-P and offset H 3ofs is stored in the memory 22.

[0107] In addition, when the number of pole pairs P is 4 as in the present embodiment, one cycle of the electrical angle of the three-phase signals Hu, Hv and Hw is equivalent to a mechanical angle of 90 degrees. Therefore, the peak-to-peak value and offset of the three-phase signals Hu, Hv and Hw can be obtained based on the digital values ​​of the three-phase signals Hu, Hv and Hw obtained during the period when the rotor shaft 110 rotates 90 degrees.

[0108] For example, when the number of pole pairs P is 5, one cycle of the electrical angle of the three-phase signals Hu, Hv, and Hw corresponds to a mechanical angle of 72 degrees, and therefore the peak-to-peak value and the offset of each of the three-phase signals Hu, Hv, and Hw can be obtained from the digital values ​​of the three-phase signals Hu, Hv, and Hw obtained during the 72-degree rotation of the rotor shaft 110. That is, when the number of pole pairs P is 5, in step S14, the processing unit 21 only needs to determine whether the rotor shaft 110 has rotated 72 degrees.

[0109] After executing the process of step S15, the processing unit 21 sets the calibration start flag to “1” (step S16). After setting the calibration start flag to “1”, the processing unit 21 ends the first angle estimation process of this time.

[0110] As can be understood from the above description, the processing unit 21 performs basic angle estimation processing based on the digital values ​​of the three-phase signals Hu, Hv, and Hw obtained from the sensor group 10 from the time when the processing unit 21 is started until the rotor shaft 110 rotates 90 degrees, thereby calculating the mechanical angle estimation value θ. Then, when the rotor shaft 110 rotates 90 degrees, the processing unit 21 converts the i-th phase signal H i The peak-peak value H iP-P and offset H iofs It is stored in the memory 22, and then the correction start flag is set to "1".

[0111] After the first angle estimation process in which the correction start flag is set to "1" is completed, the processing unit 21 starts the next first angle estimation process, obtains the digital values ​​of the three-phase signals Hu, Hv and Hw as described above (step S11), and determines whether the correction start flag is "0" (step S12). At this time, since the correction start flag is set to "1", the processing unit 21 determines that the correction start flag is not "0" (step S12: No), and transfers to the process of step S17.

[0112] When the processing unit 21 transfers to step S17, it corrects the digital values ​​of the three-phase signals Hu, Hv and Hw according to the following calculation formula (10) (step S17). i is the i-th phase signal H i The digital value of H i ' is the corrected i-th phase signal H i The digital value of the corrected i-th phase signal H is i is called the i-th phase correction signal H i '.

[0113] [Formula 7]

[0114]

[0115] Specifically, in step S17, the processing unit 21 reads the i-th phase learning signal H from the memory 22. iL Peak-to-peak learning value H iP-PL and offset learning value H iofsL , and the i-th phase signal H i The peak-peak value H iP-P and offset H iofsThen, the processing unit 21 combines the value read from the memory 22 and the i-th phase signal H obtained in step S11. i Substitute the digital value of into the above equation (10) to calculate the i-th phase correction signal H i ' numeric value.

[0116] like Figure 7 As shown, the i-th phase correction signal H calculated by the above calculation formula (10) is i The waveform of ' is the same as the i-th phase learning signal H obtained under different temperature environments iL That is, the i-th phase correction signal H calculated by the processing unit 21 according to the above calculation formula (10) is i 'It can be said that the i-th phase learning signal H iL The i-th phase signal H after temperature compensation i .

[0117] The processing unit 21 converts the i-th phase correction signal H obtained by the above calculation process into i The digital value of ' is stored in the memory 22. Thus, the digital value of the first phase correction signal H1' (corrected U-phase signal Hu), the digital value of the second phase correction signal H2' (corrected V-phase signal Hv), and the digital value of the third phase correction signal H3' (corrected W-phase signal Hw) are stored in the memory 22.

[0118] Then, the processing unit 21 reads the digital values ​​of the first phase correction signal H1', ​​the second phase correction signal H2', and the third phase correction signal H3' from the memory 22, and performs basic angle estimation processing based on the read digital values ​​(digital values ​​of the corrected three-phase signals Hu, Hv, and Hw), thereby calculating the mechanical angle estimation value θ (step S18). After executing the processing of step S18, the processing unit 21 ends the first angle estimation processing of this time.

[0119] As understood from the above description, in the first angle estimation process executed after the correction start flag is set to "1", the processing unit 21 performs the basic angle estimation process based on the digital values ​​of the temperature-compensated three-phase signals Hu, Hv, and Hw, thereby calculating the mechanical angle estimation value θ. Thus, even if the temperature when the learning process is executed is different from the temperature when the first angle estimation process is executed, the learning data obtained by the basic learning process can be appropriately used when the basic angle estimation process included in the first angle estimation process is executed, so that the angle error between the mechanical angle estimation value θ and the mechanical angle true value can be reduced.

[0120] The inventors of the present application have studied and found that the difference between the case where the basic learning process is performed at room temperature and the basic angle estimation process is performed at 85°C and the case where the basic learning process is performed at room temperature and the basic angle estimation process is performed at 85°C is different from the case where the basic learning process is performed at room temperature and the basic angle estimation process is performed at 85°C. Figure 4 The learning process shown is performed in an environment of 85°C. Figure 6 Compared with the case of the first angle estimation process shown in FIG. 1 , it is found that the angle error between the mechanical angle estimated value θ and the mechanical angle true value can be reduced to less than one third.

[0121] The first angle estimation process is particularly effective when a temperature change occurs as a disturbance. However, in addition to the temperature change, other disturbances include a magnetic field change and a change in the mounting state of the sensor magnet 120 relative to the rotor shaft 110. The second angle estimation process, which is effective when a magnetic field change or a change in the mounting state of the sensor magnet 120 relative to the rotor shaft 110 occurs as a disturbance, is described below.

[0122] Figure 8 2 is a flowchart showing the second angle estimation process executed by the processing unit 21 of the signal generating device 1 in this embodiment. The processing unit 21 repeatedly executes the second angle estimation process at a predetermined cycle. Figure 8 The second angle estimation process shown in FIG. Figure 8 As shown, when the processing unit 21 starts the second angle estimation process, it first obtains the digital values ​​of the three-phase signals Hu, Hv, and Hw (step S21).

[0123] Next, the processing unit 21 determines whether the correction start flag is "0" (step S22). As described above, the correction start flag is a flag that is reset to "0" when the processing unit 21 is started. When the correction start flag is "0" (step S22: Yes), the processing unit 21 transfers to the processing of step S23. On the other hand, when the correction start flag is not "0" (step S22: No), the processing unit 21 transfers to the processing of step S29. The following first describes the processing performed when the correction start flag is "0".

[0124] When the correction start flag is "0" (step S22: Yes), the processing unit 21 performs the basic angle estimation processing based on the digital values ​​of the three-phase signals Hu, Hv, and Hw, thereby calculating the mechanical angle estimation value θ (step S23). Then, the processing unit 21 determines whether the rotor shaft 110 has rotated one revolution based on the mechanical angle estimation value θ obtained in the past second angle estimation processing and the mechanical angle estimation value θ obtained in the current second angle estimation processing (step S24).

[0125] When the processing unit 21 determines that the rotor shaft 110 has not rotated one revolution (step S24: No), the processing of steps S25 to S28 described later is skipped and the second angle estimation processing of this time is terminated. On the other hand, when the processing unit 21 determines that the rotor shaft 110 has rotated one revolution (step S24: Yes), the processing unit 21 calculates the i-th phase signal H based on the digital values ​​of the three-phase signals Hu, Hv, and Hw obtained during the period when the rotor shaft 110 rotates one revolution. i The first intermediate value H imid1 (Step S25).

[0126] Fig. 9 is the i-th phase signal H obtained during one rotation of the rotor shaft 110 (a period from time t30 to time t34). i An example of a waveform of Fig. 9 As shown, the i-th phase signal H i One electrical angle cycle is equivalent to 90 degrees of mechanical angle. Fig. 9 In the example, the period from time t30 to time t34 corresponds to one mechanical angle cycle (mechanical angle 360 ​​degrees). Fig. 9 , the period from time t30 to time t31, the period from time t31 to time t32, the period from time t32 to time t33, and the period from time t33 to time t34 each correspond to a mechanical angle of 90 degrees.

[0127] Fig.10 Yes Fig. 9 The i-th phase signal H shown i The i-th phase signal H included in the period from time t30 to time t32 in the waveform of i The waveform is magnified. Fig. 9 and Fig.10 As shown in FIG. 1 , when a magnetic field change occurs as disturbance or a change occurs in the mounting state of the sensor magnet 120 with respect to the rotor shaft 110, the i-th phase signal H obtained when the second angle estimation process is executed is i The waveform may be a waveform in which the offset waveform W1 that changes in a wave shape is superimposed.

[0128] In step S25, the processing unit 21 calculates a first intermediate point P which is an intermediate point of the straight line L1. imid1 The value (digital value) is used as the i-th phase signal H i The first intermediate value H imid1 , wherein the straight line L1 is the i-th phase signal H obtained during the period from time t30 to time t31 i The first positive side peak point P contained in imax1 and the first negative side peak point P imin1 Connected straight lines.

[0129] In other words, in step S25, the processing unit 21 calculates the i-th phase signal H based on the following equation (11): i The first maximum value H imax1 With the first minimum value H imin1 The middle value between the first middle value H imid1 The first maximum value H imax1 is the i-th phase signal H i The first positive side peak point P, one of the positive side peak points included in imax1 In addition, the first minimum value H imin1 is the i-th phase signal H i The first positive peak point P is located among the negative peak points included in imax1 The first negative side peak point P at the rear adjacent position imin1 The value of (numeric value).

[0130] [Formula 8]

[0131]

[0132] Next, the processing unit 21 calculates the i-th phase signal H based on the digital values ​​of the three-phase signals Hu, Hv, and Hw obtained during one rotation of the rotor shaft 110. i The second intermediate value H imid2 (Step S26).

[0133] In step S26, the processing unit 21 calculates the second intermediate point P which is the intermediate point of the straight line L2. imid2 The value (digital value) is used as the i-th phase signal H i The second intermediate value H imid2 , wherein the straight line L2 is the i-th phase signal H obtained during the period from time t30 to time t32 i The first negative side peak point P contained in imin1 and the second positive side peak point P imax2 Connecting straight lines (see Fig.10 ).

[0134] In other words, in step S26, the processing unit 21 calculates the i-th phase signal H based on the following equation (12): i The first minimum value H imin1 With the second maximum value H imax2 The middle value between the two is the second middle value H imid2 The second maximum value H imax2 is the i-th phase signal H i The first negative side peak point P is located among the positive side peak points contained in imin1 The second positive side peak point P at the rear adjacent position imax2The value of (numeric value).

[0135] [Formula 9]

[0136]

[0137] Next, the processing unit 21 calculates the first intermediate value H connected according to the following calculation formula (13): imid1 and the second intermediate value H imid2 In other words, in step S27, the processing unit 21 calculates the slope ks of the straight line L3 connecting the first intermediate point P imid1 and the second midpoint P imid2 The slope ks of the straight line L3 (refer to Fig.10 ). In the following calculation formula (13), θs is the first intermediate value H imid1 The corresponding rotation angle (mechanical angle estimated value θ) and the second intermediate value H imid2 The difference in the corresponding rotation angle (mechanical angle estimation value θ). Fig.10 It can be seen that the straight line L3 is from the first intermediate point P imid1 To the second intermediate point P imid2 The tangent line (approximate straight line) of the offset waveform W1 contained in the interval.

[0138] [Formula 10]

[0139]

[0140] The processing unit 21 compares the slope ks obtained by the above calculation process with the slope indicating the direction from the first intermediate point P imid1 To the second intermediate point P imid2 The interval identification number of the interval is associated and stored in the memory 22. Figure 8 Although not shown in the figure, the processing unit 21 also performs the processing corresponding to steps S25 to S27 on the sections of other intermediate points, thereby calculating the slope ks corresponding to the sections of other intermediate points.

[0141] For example, Fig. 9 As shown, the processing unit 21 sets the third intermediate point P imid3 The digital value of the i-th phase signal H i The third intermediate value H imid3 The third intermediate point P is calculated. imid3 is connected to the i-th phase signal H i The second positive side peak point P contained in imax2 and the second negative side peak point P imin2 In other words, the processing unit 21 calculates the i-th phase signal H i The second maximum value H imax2 With the second minimum value Himin2 The middle value between the third middle value H imid3 .

[0142] Then, the processing unit 21 calculates the second intermediate value H imid2 and the third intermediate value H imid3 In other words, the processing unit 21 calculates the slope ks of the straight line connecting the second intermediate point P imid2 and the third intermediate point P imid3 More specifically, the processing unit 21 calculates the slope ks of the straight line from the second intermediate value H imid2 Subtract the third intermediate value H imid3 The value obtained is divided by the second intermediate value H imid2 The corresponding mechanical angle estimated value θ and the third intermediate value H imid3 The difference between the corresponding mechanical angle estimated values ​​θ is used to calculate the connection point P imid2 and the third intermediate point P imid3 The processing unit 21 compares the slope ks obtained by the calculation process with the slope ks representing the line from the second intermediate point P imid2 To the third intermediate point P imid3 The interval identification number of the interval is associated with each other and stored in the memory 22.

[0143] In addition, if Fig. 9 As shown, the processing unit 21 converts the fourth intermediate point P imid4 The digital value of the i-th phase signal H i The 4th intermediate value H imid4 And calculate that the fourth intermediate point P imid4 is connected to the i-th phase signal H i The second negative side peak point P included in imin2 and the third positive side peak point P imax3 In other words, the processing unit 21 calculates the i-th phase signal H i The third maximum value H imax3 With the second minimum value H imin2 The middle value between the fourth middle value H imid4 .

[0144] Then, the processing unit 21 calculates the third intermediate value H imid3 and the 4th intermediate value H imid4 In other words, the processing unit 21 calculates the slope ks of the straight line connecting the third intermediate point P imid3 and the 4th intermediate point P imid4 More specifically, the processing unit 21 calculates the slope ks of the straight line from the third intermediate value H imid3 Subtract the 4th intermediate value H imid4 The value obtained is divided by the third intermediate value H imid3The corresponding mechanical angle estimated value θ and the fourth intermediate value H imid4 The difference between the corresponding mechanical angle estimated values ​​θ is used to calculate the connection point P imid3 and the 4th intermediate point P imid4 The processing unit 21 compares the slope ks obtained by the calculation process with the slope ks representing the line from the third intermediate point P imid3 To the 4th intermediate point P imid4 The interval identification number of the interval is associated with each other and stored in the memory 22.

[0145] In addition, if Fig. 9 As shown, the processing unit 21 converts the fifth intermediate point P imid5 The digital value of the i-th phase signal H i The 5th median value H imid5 And calculate that the fifth intermediate point P imid5 is connected to the i-th phase signal H i The third positive side peak point P contained in imax3 and the third negative side peak point P imin3 In other words, the processing unit 21 calculates the i-th phase signal H i The third maximum value H imax3 With the third minimum value H imin3 The middle value between the 5th middle value H imid5 .

[0146] Then, the processing unit 21 calculates the fourth intermediate value H imid4 and the 5th intermediate value H imid5 In other words, the processing unit 21 calculates the slope ks of the straight line connecting the fourth intermediate point P imid4 and the 5th midpoint P imid5 More specifically, the processing unit 21 calculates the slope ks of the straight line from the fourth intermediate value H imid4 Subtract the 5th intermediate value H imid5 The value obtained is divided by the 4th intermediate value H imid4 The corresponding mechanical angle estimated value θ and the fifth intermediate value H imid5 The difference between the corresponding mechanical angle estimated values ​​θ is used to calculate the fourth intermediate point P imid4 and the 5th midpoint P imid5 The processing unit 21 compares the slope ks obtained by the calculation process with the slope ks representing the line from the fourth intermediate point P imid4 To the 5th intermediate point P imid5 The interval identification number of the interval is associated with each other and stored in the memory 22.

[0147] In addition, if Fig. 9 As shown, the processing unit 21 converts the sixth intermediate point P imid6 The digital value of the i-th phase signal Hi The 6th intermediate value H imid6 And calculate, the sixth intermediate point P imid6 is connected to the i-th phase signal H i The third negative side peak point P included in imin3 and the 4th positive side peak point P imax4 In other words, the processing unit 21 calculates the i-th phase signal H i The fourth maximum value H imax4 With the third minimum value H imin3 The middle value between the six middle values ​​H imid6 .

[0148] Then, the processing unit 21 calculates the fifth intermediate value H imid5 and the 6th intermediate value H imid6 In other words, the processing unit 21 calculates the slope ks of the straight line connecting the fifth intermediate point P imid5 and the sixth intermediate point P imid6 More specifically, the processing unit 21 calculates the slope ks of the straight line from the fifth intermediate value H imid5 Subtract the 6th intermediate value H imid6 The value obtained is divided by the 5th intermediate value H imid5 The corresponding mechanical angle estimated value θ and the sixth intermediate value H imid6 The difference between the corresponding mechanical angle estimated values ​​θ is used to calculate the connection point P imid5 and the sixth intermediate point P imid6 The processing unit 21 compares the slope ks obtained by the calculation process with the slope ks representing the line from the fifth intermediate point P imid5 To the 6th intermediate point P imid6 The interval identification number of the interval is associated with each other and stored in the memory 22.

[0149] In addition, if Fig. 9 As shown, the processing unit 21 converts the seventh intermediate point P imid7 The digital value of the i-th phase signal H i The 7th median value H imid7 And calculate that the seventh intermediate point P imid7 is connected to the i-th phase signal H i The fourth positive side peak point P contained in imax4 and the 4th negative side peak point P imin4 In other words, the processing unit 21 calculates the i-th phase signal H i The fourth maximum value H imax4 With the 4th minimum value H imin4 The middle value between the 7th middle value H imid7 .

[0150] Then, the processing unit 21 calculates the sixth intermediate value Himid6 and the 7th intermediate value H imid7 In other words, the processing unit 21 calculates the slope ks of the straight line connecting the sixth intermediate point P imid6 and the 7th midpoint P imid7 More specifically, the processing unit 21 calculates the slope ks of the straight line from the sixth intermediate value H imid6 Subtract the 7th intermediate value H imid7 The value obtained is divided by the 6th intermediate value H imid6 The corresponding mechanical angle estimated value θ and the seventh intermediate value H imid7 The difference between the corresponding mechanical angle estimated values ​​θ is used to calculate the sixth intermediate point P imid6 and the 7th midpoint P imid7 The processing unit 21 compares the slope ks obtained by the calculation process with the slope ks representing the line from the sixth intermediate point P imid6 To the 7th midpoint P imid7 The interval identification number of the interval is associated with each other and stored in the memory 22.

[0151] In addition, if Fig. 9 As shown, the processing unit 21 converts the eighth intermediate point P imid8 The digital value of the i-th phase signal H i The 8th median value H imid8 And calculate that the 8th intermediate point P imid8 is connected to the i-th phase signal H i The fourth negative side peak point P included in imin4 and the first positive side peak point P imax1 In other words, the processing unit 21 calculates the i-th phase signal H i The first maximum value H imax1 With the 4th minimum value H imin4 The middle value between the 8th middle value H imid8 .

[0152] Then, the processing unit 21 calculates the seventh intermediate value H imid7 and the 8th intermediate value H imid8 In other words, the processing unit 21 calculates the slope ks of the straight line connecting the seventh intermediate point P imid7 and the 8th midpoint P imid8 More specifically, the processing unit 21 calculates the slope ks of the straight line from the seventh intermediate value H imid7 Subtract the 8th median value H imid8 The value obtained is divided by the 7th intermediate value H imid7 The corresponding mechanical angle estimated value θ and the 8th intermediate value H imid8 The difference between the corresponding mechanical angle estimated values ​​θ is used to calculate the seventh intermediate point P imid7 and the 8th midpoint P imid8The processing unit 21 compares the slope ks obtained by the calculation process with the slope ks representing the seventh intermediate point P. imid7 To the 8th midpoint P imid8 The interval identification number of the interval is associated with each other and stored in the memory 22.

[0153] Then, the processing unit 21 calculates the eighth intermediate value H imid8 and the first intermediate value H imid1 In other words, the processing unit 21 calculates the slope ks of the straight line connecting the eighth intermediate point P imid8 and the first intermediate point P imid1 More specifically, the processing unit 21 calculates the slope ks of the straight line from the 8th intermediate value H imid8 Subtract the first intermediate value H imid1 The value obtained is divided by the 8th intermediate value H imid8 The corresponding mechanical angle estimated value θ and the first intermediate value H imid1 The difference between the corresponding mechanical angle estimated values ​​θ is used to calculate the connection of the 8th intermediate point P imid8 and the first intermediate point P imid1 The processing unit 21 compares the slope ks obtained by the calculation process with the slope ks representing the line from the eighth intermediate point P imid8 To the first intermediate point P imid1 The interval identification number of the interval is associated with each other and stored in the memory 22.

[0154] As described above, the processing unit 21 performs the processing corresponding to steps S25 to S27 for the other intermediate point sections and then sets the correction start flag to "1" (step S28). After setting the correction start flag to "1", the processing unit 21 ends the second angle estimation processing of this time.

[0155] As can be understood from the above description, the processing unit 21 performs basic angle estimation processing based on the digital values ​​of the three-phase signals Hu, Hv, and Hw obtained from the sensor group 10 from the time when the processing unit 21 is started until the rotor shaft 110 rotates once, thereby calculating the mechanical angle estimation value θ. Then, when the rotor shaft 110 rotates once, the processing unit 21 calculates the mechanical angle estimation value θ for the i-th phase signal H i After the slope ks calculated for each section including the intermediate point is stored in the memory 22, the correction start flag is set to "1".

[0156] After the second angle estimation process in which the correction start flag is set to "1" is completed, the processing unit 21 obtains the digital values ​​of the three-phase signals Hu, Hv, and Hw as described above when starting the next second angle estimation process (step S21), and determines whether the correction start flag is "0" (step S22). At this time, since the correction start flag is set to "1", the processing unit 21 determines that the correction start flag is not "0" (step S22: No), and transfers to the processing of step S29.

[0157] When the processing unit 21 moves to step S29, it calculates the i-th phase signal H according to the following calculation formula (14): i The offset H iofs (Step S29). Specifically, the processing unit 21 generates a signal based on the i-th phase signal H acquired at time t in step S21. i The digital value H it , determine the current midpoint interval. For example, Fig.10 As shown, in the i-th phase signal H i The digital value of H it Included in the first intermediate point P imid1 To the second intermediate point P imid2 In the case of the interval of imid1 To the second intermediate point P imid2 The interval is determined as the interval of the current midpoint.

[0158] In this case, the processing unit 21 reads out from the memory 22 the data corresponding to the data indicating the first intermediate point P. imid1 To the second intermediate point P imid2 Then, the processing unit 21 compares the slope ks read from the memory 22 with the first intermediate value H imid1 Substitute into the following equation (14) to calculate the i-th phase signal H i The digital value of H it The corresponding offset H iofs .

[0159] like Fig.10 As shown in the following calculation formula (14), Δθ is the first intermediate value H imid1 The corresponding rotation angle (mechanical angle estimation value θ) and the i-th phase signal H i The value (digital value H it ) is the difference in the rotation angle (mechanical angle estimation value θ) corresponding to . Fig.10 As shown, the offset H in this case iofs is point P on line L3 iofs The value of .

[0160] [Formula 11]

[0161] H iofs =ksΔθ+H imid1 …(14)

[0162] For example, the processing unit 21 may calculate Δθ by performing the following calculation. First, the processing unit 21 calculates the offset H based on the following calculation formula (15). iofs The mechanical angle estimation value θ0 used in the calculation of θ1 is used. In the calculation formula (15), θ1 is the mechanical angle estimation value calculated in the previous basic angle estimation process, and θ2 is the mechanical angle estimation value calculated in the previous basic angle estimation process. Then, the processing unit 21 calculates Δθ according to the following calculation formula (16). In the calculation formula (16), θ is the difference between the first intermediate value H imid1 The corresponding mechanical angle estimated value.

[0163] θ0=θ1-θ2+θ1…(15)

[0164] Δθ=θ0-θ…(16)

[0165] In addition, for example, in the i-th phase signal H i The digital value H it Included in the second intermediate point P imid2 To the third intermediate point P imid3 In the case of the interval of imid2 To the third intermediate point P imid3 In this case, the processing unit 21 reads out from the memory 22 the data corresponding to the data indicating the interval from the second intermediate point P imid2 To the third intermediate point P imid3 Then, the processing unit 21 adds the second intermediate value H to the value obtained by multiplying the slope ks read from the memory 22 by Δθ. imid2 , to calculate the offset H iofs In this case, Δθ is equal to the second intermediate value H imid2 The corresponding mechanical angle estimated value θ and the i-th phase signal H i The value (digital value H it ) is the difference between the estimated mechanical angle θ corresponding to the value.

[0166] Next, the processing unit 21 calculates the i-th phase signal H i The peak-peak value H iP-P (Step S30). For example, when the first intermediate point P imid1 To the second intermediate point P imid2 When the interval of the current midpoint is determined, the processing unit 21 calculates the first maximum value H imax1 With the first minimum value H imin1The difference is taken as the peak-peak value H iP-P In addition, for example, when moving from the second intermediate point P imid2 To the third intermediate point P imid3 When the interval of the current midpoint is determined, the processing unit 21 calculates the second maximum value H imax2 With the first minimum value H imin1 The difference is taken as the peak-peak value H iP-P .

[0167] Next, the processing unit 21 corrects the digital values ​​of the three-phase signals Hu, Hv, and Hw based on the following calculation formula (10) (step S31). Specifically, in step S31, the processing unit 21 reads the i-th phase learning signal H from the memory 22. iL Peak-to-peak learning value H iP-PL And the offset learning value H iofsL Then, the processing unit 21 calculates the learning values ​​read from the memory 22 and the i-th phase signal H obtained in step S21. i The digital value of the offset H calculated in step S29 iofs , the peak-to-peak value H calculated in step S30 iP-P Substitute the following equation (10) to calculate the i-th phase correction signal H i ' numeric value.

[0168] [Formula 12]

[0169]

[0170] Although not shown in the figure, the i-th phase correction signal H calculated by the above equation (10) is i The waveform of ' is different from the i-th phase learning signal H obtained in an environment with different magnetic fields or installation states of the sensor magnet 120 relative to the rotor shaft 110. iL That is, the i-th phase correction signal H calculated by the processing unit 21 according to the above calculation formula (10) is i 'It can be said that the i-th phase learning signal H iL The i-th phase signal H after magnetic field compensation etc. i .

[0171] The processing unit 21 converts the i-th phase correction signal H obtained by the above calculation process into i The digital value of ' is stored in the memory 22. Thus, the digital value of the first phase correction signal H1' (corrected U-phase signal Hu), the digital value of the second phase correction signal H2' (corrected V-phase signal Hv), and the digital value of the third phase correction signal H3' (corrected W-phase signal Hw) are stored in the memory 22.

[0172] Then, the processing unit 21 reads the digital values ​​of the first phase correction signal H1', ​​the second phase correction signal H2', and the third phase correction signal H3' from the memory 22, and performs basic angle estimation processing based on the read digital values ​​(digital values ​​of the corrected three-phase signals Hu, Hv, and Hw), thereby calculating the mechanical angle estimation value θ (step S32). After executing the processing of step S32, the processing unit 21 ends the second angle estimation processing of this time.

[0173] As understood from the above description, in the second angle estimation process executed after the correction start flag is set to "1", the processing unit 21 performs the basic angle estimation process based on the digital values ​​of the three-phase signals Hu, Hv, and Hw after the magnetic field compensation, etc., thereby calculating the mechanical angle estimated value θ. Therefore, even when the magnetic field changes or the change in the mounting state of the sensor magnet 120 with respect to the rotor shaft 110 occurs as interference, the learning data obtained by the basic learning process can be appropriately used when the basic angle estimation process included in the second angle estimation process is executed, so that the angle error between the mechanical angle estimated value θ and the mechanical angle true value can be reduced.

[0174] As described above, according to the present embodiment, compared with the basic patent method disclosed in Japanese Patent Gazette No. 6233532, even when the environment during which the basic learning process is executed is different from the environment during which the first angle estimation process or the second angle estimation process is executed, the learning data obtained by the basic learning process can be appropriately used when the basic angle estimation process included in the first angle estimation process or the second angle estimation process is executed, thereby reducing the angle error between the mechanical angle estimation value θ and the mechanical angle true value, thereby achieving an improvement in the mechanical angle estimation accuracy of the rotor shaft 110.

[0175] (Variation Example)

[0176] The present invention is not limited to the above-described embodiment, and each configuration described in this specification can be appropriately combined within a range that does not contradict each other.

[0177] For example, in the above embodiment, the combination of the motor 100 and the signal generating device 1 is exemplified, but the present invention is not limited to this embodiment, and a combination of a sensor magnet attached to a rotating shaft and a signal generating device may also be used.

[0178] For example, in the above embodiment, the first magnetic sensor 11, the second magnetic sensor 12, and the third magnetic sensor 13 are arranged in a state opposite to the disc-shaped sensor magnet 120 in the axial direction of the rotor shaft 110, but the present invention is not limited to this method. For example, when a ring magnet is used instead of a disc-shaped sensor magnet, since the magnetic flux flows in the radial direction of the ring magnet, the first magnetic sensor 11, the second magnetic sensor 12, and the third magnetic sensor 13 may also be arranged in a state opposite to the ring magnet in the radial direction of the ring magnet.

[0179] For example, in the above embodiment, the sensor magnet 120 mounted on the rotor shaft 110 of the motor 100 is used as a rotating magnet, but a rotor magnet mounted on the rotor of the motor 100 may also be used as a rotating magnet. The rotor magnet is also a magnet that rotates synchronously with the rotor shaft 110 and has a plurality of magnetic pole pairs.

[0180] In the above embodiment, the sensor group 10 includes three magnetic sensors 11, 12, and 13, but the number of magnetic sensors is not limited to three, and may be N (N is a multiple of 3). In addition, 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. When a rotor magnet is used as a position detection magnet, the number of pole pairs of the rotor magnet is also not limited to four.

[0181] exist Figure 6 In the first angle estimation process shown in the figure, after the correction start flag becomes "1", the peak-to-peak value H obtained from the start of the processing unit 21 until the rotor shaft 110 rotates 90 degrees is used. iP-P and offset H iofs , correct the digital values ​​of the three-phase signals Hu, Hv and Hw. However, it is also considered that the temperature also changes after the correction start flag becomes "1".

[0182] Therefore, for example, the processing unit 21 may obtain the peak-to-peak value H every time the rotor shaft 110 rotates 90° from the start of the processing unit 21. iP-P and offset H iofs In this case, the processing unit 21 uses the peak-to-peak value H obtained during the period when the rotor shaft 110 rotates 90° from the start of the processing unit 21. iP-P and offset H iofs The processing unit 21 uses the peak-to-peak value H obtained during the period when the rotor shaft 110 rotates from 90° to 180° to correct the digital values ​​of the three-phase signals Hu, Hv, and Hw obtained during the period when the rotor shaft 110 rotates from 90° to 180°. iP-P and offset H iofs, the digital values ​​of the three-phase signals Hu, Hv and Hw obtained during the period when the rotor shaft 110 rotates from 180° to 270° are corrected.

[0183] In addition, the processing unit 21 uses the peak-to-peak value H obtained during the period when the rotor shaft 110 rotates from 180° to 270°. iP-P and offset H iofs , the digital values ​​of the three-phase signals Hu, Hv, and Hw obtained during the period when the rotor shaft 110 rotates from 270° to 360° are corrected. In addition, the processing unit 21 uses the peak-to-peak value H obtained during the period when the rotor shaft 110 rotates from 270° to 360° iP-P and offset H iofs To correct the digital values ​​of the three-phase signals Hu, Hv, and Hw obtained during the period when the rotor shaft 110 rotates from 360 degrees (0 degrees) to 450 degrees (90 degrees).

[0184] In addition, basically, due to the peak-to-peak value H iP-P and offset H iofs It is different in each angular range, so for example, if the peak-to-peak value H obtained in the range of 0 to 90 degrees in the previous rotation is iP-P and offset H iofs , it is preferably used to correct the digital values ​​of the three-phase signals Hu, Hv and Hw obtained in the range of 0 to 90 degrees in this one rotation. Thereby, the correction effect can be improved. The same applies to the ranges of 90° to 180°, 180° to 270° and 270° to 360°.

[0185] exist Figure 8 In the second angle estimation process shown, after the correction start flag becomes "1", the digital values ​​of the three-phase signals Hu, Hv and Hw are corrected using the slope ks obtained from the start of the processing unit 21 to the rotation of the rotor shaft 110. However, it is also considered that the magnetic field environment and the like also change after the correction start flag becomes "1".

[0186] Therefore, for example, the processing unit 21 may obtain the slope ks each time the rotor shaft 110 rotates one circle after the processing unit 21 is started. In other words, the processing unit 21 may obtain the slope ks each time the rotor shaft 110 rotates 360 degrees after the processing unit 21 is started. In this case, the processing unit 21 uses the slope ks obtained from the start of the processing unit 21 to the time when the rotor shaft 110 rotates 360 degrees to correct the digital values ​​of the three-phase signals Hu, Hv, and Hw obtained during the period when the rotor shaft 110 rotates from 360 degrees to 720 degrees. In addition, the processing unit 21 uses the slope ks obtained during the period when the rotor shaft 110 rotates from 360 degrees to 720 degrees to correct the digital values ​​of the three-phase signals Hu, Hv, and Hw obtained during the period when the rotor shaft 110 rotates from 720 degrees to 1080 degrees.

[0187] Explanation of symbols

[0188] 1Signal generating device

[0189] 10 sensor groups

[0190] 111st magnetic sensor

[0191] 12 2nd magnetic sensor

[0192] 133rd magnetic sensor

[0193] 20Signal Processing Unit

[0194] 21 Processing Department

[0195] 22 Memory

[0196] 100 motors

[0197] 110 rotor shaft (rotating body)

[0198] 120 sensor magnet.

Claims

1. A signal generating device, characterized in that: The signal generating device comprises: N sensors, which output N-phase signals according to the rotation angle of the rotating body, wherein N is a multiple of 3; and a signal processing unit that corrects the N-phase signal based on equation (10), In the above equation (10), H i is the i-th phase signal, H i ' is the corrected i-th phase signal, H iP-P is the maximum value H of the i-th phase signal imax With the minimum value H imin The difference, H iofs is the offset of the i-th phase signal, H iP-PL is the differential H iP-P The learning value, H iofsL is the offset H iofs where i is an integer from 1 to N. [Formula 1] 2. The signal generating device according to claim 1, characterized in that: The signal processing unit calculates the offset H of the i-th phase signal according to equation (9): iofs ,[Formula 2] 3. The signal generating device according to claim 1, characterized in that: The signal processing unit performs the following processing: Based on equation (11), the first maximum value H of the i-th phase signal is calculated: imax1 With the first minimum value H imin1 The middle value between the first middle value H imid1 ; Based on equation (12), the first minimum value H of the i-th phase signal is calculated: imin1 With the second maximum value H imax2 The middle value between the two is the second middle value H imid2 ; Based on the calculation formula (13), the first intermediate value H is calculated imid1 and the second intermediate value H imid2 the slope of the line ks; and Based on equation (14), the offset H of the i-th phase signal is calculated as iofs , The first maximum value H imax1 is the value of the first positive-side peak point which is one of the positive-side peak points included in the i-th phase signal, The first minimum value H imin1 is the value of the first negative peak point located adjacent to the first positive peak point among the negative peak points included in the i-th phase signal, The second maximum value H imax2 is the value of the second positive peak point located adjacent to the first negative peak point among the positive peak points included in the i-th phase signal, In the above calculation formula (13), θs is the first intermediate value H imid1 The corresponding rotation angle and the second intermediate value H imid2 The corresponding difference in the rotation angle, In the above calculation formula (14), Δθ is the first intermediate value H imid1 The difference between the rotation angle corresponding to the value of the i-th phase signal and the rotation angle corresponding to the value of the i-th phase signal, [Formula 3] H iofs =ksΔθ+H imid1 …(14)。 4. The signal generating device according to any one of claims 1 to 3, characterized in that: The sensor is a magnetic sensor.

5. A signal generation method using N sensors that output N-phase signals according to the rotation angle of a rotating body, wherein: N is a multiple of 3, characterized in that: The signal generation method includes the step of correcting the N-phase signal based on equation (10), In the above equation (10), H i is the i-th phase signal, H i ' is the corrected i-th phase signal, H iP-P is the maximum value H of the i-th phase signal imax With the minimum value H imin The difference, H iofs is the offset of the i-th phase signal, H iP-PL is the differential H iP-P The learning value, H iofsL is the offset H iofs where i is an integer from 1 to N. [Formula 4] 6. The signal generating method according to claim 5, characterized in that: The step of correcting the N-phase signal comprises: calculating the offset H of the i-th phase signal according to equation (9): iofs Steps, [Formula 5] 7. The signal generating method according to claim 5, characterized in that: The step of correcting the N-phase signal comprises the following steps: Based on equation (11), the first maximum value H of the i-th phase signal is calculated: imax1 With the first minimum value H imin1 The middle value between the first middle value H imid1 ; Based on equation (12), the first minimum value H of the i-th phase signal is calculated: imin1 With the second maximum value H imax2 The middle value between the two is the second middle value H imid2 ; Based on the calculation formula (13), the first intermediate value H is calculated imid1 and the second intermediate value H imid2 the slope of the line ks; and Based on equation (14), the offset H of the i-th phase signal is calculated as iofs , The first maximum value H imax1 is the value of the first positive-side peak point which is one of the positive-side peak points included in the i-th phase signal, The first minimum value H imin1 is the value of the first negative peak point located adjacent to the first positive peak point among the negative peak points included in the i-th phase signal, The second maximum value H imax2 is the value of the second positive peak point located adjacent to the first negative peak point among the positive peak points included in the i-th phase signal, In the above calculation formula (13), θs is the first intermediate value H imid1 The corresponding rotation angle and the second intermediate value H imid2 The corresponding difference in the rotation angle, In the above calculation formula (14), Δθ is the first intermediate value H imid1 The difference between the rotation angle corresponding to the value of the i-th phase signal and the rotation angle corresponding to the value of the i-th phase signal, [Formula 6] H iofs =ksΔθ+H imid1 …(14)。 8. The signal generating method according to any one of claims 5 to 7, characterized in that: The sensor is a magnetic sensor.

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