TWI784624B - Motor steering detection system and steering detection method - Google Patents

Abstract

A motor steering detection system includes a motor, a Hall sensor, an electromotive force detector, and a processor. The motor has a stator and a rotor. The stator has a coil. The Hall sensor is configured to generate a Hall voltage signal by sensing the magnetic field of the rotor. The Hall sensor and the coil are respectively at a first axis and a second axis through the stator and the rotor. The electromotive force detector is configured to generate an electromotive force signal by sensing the coil. The processor is configured to rectify the electromotive force signal to generate a rectified signal according to the Hall voltage signal, to filter the rectified signal to generate a filtered signal, and to generate a steering result for determining the steering of the motor according to the filtered signal.

Description

Motor steering detection system and steering detection method

The invention relates to a motor technology, in particular to a motor steering detection system and a steering detection method.

Motors are currently the most common source of power in industrial applications to drive various tool sets. Motors can be classified into DC motors and AC motors. AC motors are mainly divided into induction motors (Induction Motor, IM) and brushless DC motors (Brushless DC Motor, BLDC). Among them, brushless DC motors are used the most because of their simplicity, low price, fast response, and torque. It has the characteristics of large size, continuous and frequent starting, stopping, braking and reversing, so it has become one of the important equipment for automation.

When the motor is going to start in idling, it is necessary to know the rotor speed and direction of rotation first, so that the starting process is smooth and safe. In general applications, the rotation speed information and steering information of the rotor can be calculated by relying on a plurality of Hall elements. However, as the number of phases or poles of the motor increases, the number of Hall elements used to calculate the rotation speed information and steering information also needs to increase, resulting in increased manufacturing costs and increased circuit complexity.

In view of the above, the present invention provides a motor steering detection system and a steering detection method. According to some embodiments, the present invention can reduce the number of Hall elements required for judging the turning direction of the motor, so as to reduce the manufacturing cost and circuit complexity.

According to some embodiments, a motor steering detection system includes a motor, a Hall sensor, an induced electromotive force detector, and a processor. The motor has a stator and a rotor. The stator has a coil. The Hall sensor is used for inducing a magnetic field of the rotor to generate a Hall voltage signal. The Hall sensor and the coil are respectively located on a different first axis and a second axis passing through the stator and the rotor. The induced electromotive force detector is used for detecting the coil to generate an induced electromotive force signal. The processor is used to rectify the induced electromotive force signal according to the Hall voltage signal to generate a rectified signal; filter the rectified signal to generate a filtered signal; and generate a steering information according to the filtered signal for judging the steering of the motor.

According to some embodiments, the steering detection method is adapted to a motor, a Hall sensor, an induced electromotive force detector and a processor. The motor has a stator and a rotor. The stator has a coil. The steering detection method includes rectifying an induced electromotive force signal according to a hall voltage signal to generate a rectified signal; filtering the rectified signal to generate a filtered signal; and generating a steering information based on the filtered signal for judging the motor steering. The Hall voltage signal is generated by the Hall sensor sensing the magnetic field of the rotor. The induced electromotive force signal is generated by the detection coil of the induced electromotive force detector. The Hall sensor and the coil are respectively located on a different first axis and a second axis passing through the stator and the rotor.

To sum up, according to some embodiments, the rotation direction of the motor can be determined through the Hall sensors, the induced electromotive force detectors and their locations, thereby reducing the number of required Hall elements. According to some embodiments, since the induced electromotive force detector can have a simple circuit structure, the manufacturing cost and the complexity of the circuit design can be reduced.

Referring to FIG. 1 , FIG. 1 is a schematic diagram of a motor steering detection system 10 according to some embodiments of the present invention. The motor steering detection system 10 includes a motor 11 , a Hall sensor 12 , an induced electromotive force detector 13 and a processor 14 . The processor 14 is electrically connected to the Hall sensor 12 , the induced electromotive force detector 13 and the motor 11 . The motor 11 has a rotor 20 and a stator 30 for energy conversion between electrical energy and mechanical energy. The stator 30 has coils 31U~31W to drive the rotor 20 to rotate after being energized. The induced electromotive force detector 13 is electrically connected to one of the coils 31U˜31W. Here, FIG. 1 takes the motor 11 as a three-phase motor as an example, and shows three coils 31U~31W corresponding to one of the three phases, but the present invention is not limited thereto, and the number of coils can be greater than or is less than three, and the motor 11 can also be a motor with other phases (for example, a single-phase motor). In some embodiments, the motor 11 may be a DC motor, an induction motor, a brushless DC motor, or a permanent-magnet synchronous motor (Permanent-magnet synchronous motor, PMSM) and the like.

The Hall sensor 12 is used for inducing the magnetic field of the rotor 20 to generate a Hall voltage signal HV. From the Hall voltage signal HV, the position information of the rotor 20 (that is, the current position of the rotor 20 in the motor 11 ) can be analyzed. Taking the motor 11 as an example of a three-phase motor, the processor 14 can determine which of the three phases corresponds to the coils 31U~31W to be energized to drive the rotation of the rotor 20 according to the position information. The processor 14 may be an arithmetic circuit such as a microcontroller or a system on a chip. In some embodiments, the Hall sensor 12 may be disposed on the stator 30 . In some embodiments, the Hall sensor 12 may be disposed between two of the coils 31U˜ 31W.

The induced electromotive force detector 13 is used to detect the coils 31U˜ 31W to generate an induced electromotive force signal BEMF. Specifically, the induced electromotive force signal BEMF is a back electromotive force (Back electromotive force) signal. For example, according to Faraday's law, when a conductor cuts a magnetic field, an electromotive force is induced in the conductor. As shown in Figure 1, the induced electromotive force detector 13 is electrically connected to the coil 31U. When the rotor 20 rotates, the coil 31U relatively cuts the magnetic field of the rotor 20, thereby generating an induced electromotive force, and because the phase of the induced electromotive force is opposite to that of the opposite The phase of the potential applied by the coil 31U, so the induced electromotive force is the counter electromotive force. The induced electromotive force detector 13 detects the back electromotive force to generate an induced electromotive force signal BEMF.

Referring to FIG. 2 , FIG. 2 is a schematic flowchart of a steering detection method according to some embodiments of the present invention. The steering detection method is suitable to be implemented by the motor steering detection system 10 . First, the processor 14 rectifies the induced electromotive force signal BEMF according to the Hall voltage signal HV to generate a rectified signal RS (as shown in FIG. 5 and FIG. 6 ) (step S100 ). Next, the processor 14 filters the rectified signal RS to generate a filtered signal FS (as shown in FIG. 5 and FIG. 6 ) (step S102 ). Afterwards, the processor 14 generates steering information according to the filtered signal FS (step S104 ). The steering information indicates the steering direction of the motor 11 . In other words, through the steering information, the processor 14 can determine whether the rotor 20 of the motor 11 is rotating forward or reverse. Therefore, the turning direction of the motor 11 can be judged by the single Hall sensor 12, the induced electromotive force detector 13 and the Hall voltage signal HV and the induced electromotive force signal BEMF generated respectively (that is, reducing the need for judgment number of Hall sensors required for turning the motor 11). In some embodiments, the processor 14 performs low-pass filtering on the rectified signal RS in order to make the values of the filtered signal FS all positive or negative so as to subsequently generate steering information.

Referring to FIG. 3 , FIG. 3 is a schematic diagram of the rotor 20 and the induced electromotive force detector 13 according to some embodiments of the present invention. In some embodiments, the induced electromotive force detector 13 includes a first voltage dividing resistor R1 , a second voltage dividing resistor R2 and an output node ND. The first voltage dividing resistor R1 is electrically connected to the coil 31U, and the second voltage dividing resistor R2 is electrically connected to the reference ground GND. The output node ND is located between the first voltage dividing resistor R1 and the second voltage dividing resistor R2. When the magnetic flux of the coil 31U changes, the coil 31U generates a current in the first voltage-dividing resistor R1 and the second voltage-dividing resistor R2, and the first voltage-dividing resistor R1 and the second voltage-dividing resistor R2 output at the output node ND according to the current. Induced electromotive force signal BEMF. In this way, the back electromotive force generated by the coil 31U can be reduced through the first voltage dividing resistor R1 and the second voltage dividing resistor R2, and the reduced back electromotive force can be output as the induced electromotive force signal BEMF to meet the electrical specification of the motor 11 (For example, the induced electromotive force detector 13 generates the induced electromotive force signal BEMF without burning the motor 11 ). In some embodiments, the resistance values of the first voltage dividing resistor R1 and the second voltage dividing resistor R2 may be the same or different. In some embodiments, the resistance values of the first voltage dividing resistor R1 and the second voltage dividing resistor R2 can be configured according to the specifications of the motor 11 . In some embodiments, since the induced electromotive force detector 13 can be implemented with a simple structure, the manufacturing cost and the complexity of the circuit design are reduced.

為感應電動勢，

為磁通量，t為時間。在一些實施例中，曲線MF的正半波與負半波的交界處是發生在線圈31U對應至轉子20的磁交界時。在曲線MF的正半波與負半波的交界處時，感應電動勢訊號BEMF為波峰或是波谷，且感應電動勢訊號BEMF中的單一半波因波峰或是波谷而對稱。在一些實施例中，曲線MF中的一個週期（例如曲線MF經歷一個正半波及一個負半波），表示轉子20已轉一圈360度的電氣角。 Referring to FIG. 4 , FIG. 4 is a schematic diagram of the induced electromotive force signal BEMF and the magnetic flux change of the coil 31U caused by the rotor 20 in some embodiments of the present invention. The curve MF is the change of the magnetic flux of the coil 31U due to the magnetic field of the rotor 20 . For example, when the north pole (“N” pole) of the magnetic field of the rotor 20 passes through the coil 31U, the coil 31U generates a positive half-wave magnetic flux of a sine wave due to the magnetic field of the rotor 20 (such as the positive half-wave of the curve MF). When the south pole ("S" pole) of the magnetic field of the rotor 20 passes through the coil 31U, the coil 31U generates magnetic flux of the negative half wave of the sine wave due to the magnetic field of the rotor 20 (such as the negative half wave of the curve MF). According to Faraday's law, there is a relationship between the back electromotive force and the magnetic flux as shown in Equation 1. Therefore, according to Equation 1 and the curve MF, the induced electromotive force signal BEMF as shown in FIG. 4 can be obtained. Formula 1

is the induced electromotive force,

is the magnetic flux, and t is the time. In some embodiments, the junction of the positive half-wave and the negative half-wave of the curve MF occurs when the coil 31U corresponds to the magnetic junction of the rotor 20 . At the intersection of the positive half-wave and the negative half-wave of the curve MF, the induced electromotive force signal BEMF is a peak or a trough, and the single half-wave of the induced electromotive force signal BEMF is symmetrical due to the peak or trough. In some embodiments, one cycle in the curve MF (eg, the curve MF goes through a positive half-wave and a negative half-wave) indicates that the rotor 20 has rotated an electrical angle of 360 degrees.

…………………………（式1）

…………………………(Formula 1)

Refer to FIG. 5 and FIG. 6 . 5 is a schematic diagram of the Hall voltage signal HV, the induced electromotive force signal BEMF, the rectified signal RS and the filtered signal FS according to the first embodiment of the present invention. 6 is a schematic diagram of the Hall voltage signal HV, the induced electromotive force signal BEMF, the rectified signal RS and the filtered signal FS according to the second embodiment of the present invention. The first embodiment is a signal when the rotor 20 of the motor 11 is rotating forward, and the second embodiment is a signal when the rotor 20 of the motor 11 is rotating reversely. In some embodiments, as shown in FIG. 5 and FIG. 6 , when the Hall sensor 12 senses that the magnetic field of the rotor 20 is north, it generates a high-level Hall voltage signal HV (for example, the logic level is “ 1” Hall voltage signal HV), when the Hall sensor 12 senses that the magnetic field of the rotor 20 is the south pole, it generates a low-level Hall voltage signal HV (such as a Hall with a logic level of “0”) voltage signal HV). Wherein, a period of the Hall voltage signal HV (for example, the Hall voltage signal HV goes through a high level and a low level) indicates that the rotor 20 has rotated an electrical angle of 360 degrees.

In some embodiments of step S100, as shown in FIG. 5 and FIG. 6, the processor 14 maintains the induced electromotive force signal BEMF when the Hall voltage signal HV is at a high level, and maintains the induced electromotive force signal BEMF when the Hall voltage signal HV is at a low level. When , the induced electromotive force signal BEMF is converted into a negative value, thereby generating a rectified signal RS. In this way, the rectified induced electromotive force signal BEMF (that is, the rectified signal RS) can have positive and negative values for subsequent filtering processing.

In some embodiments of step S102 , the processor 14 may integrate the rectified signal RS through a filter (such as an R-C filter) to generate the filtered signal FS. Wherein, the filter may be an analog filter or a digital filter. The aforementioned integral operation can be shown in Equation 2~Equation 4, where RR is the resistance value of the R-C filter, IN is the current value of the input signal (such as the rectified signal RS) of the R-C filter, and OUT_now is the output signal of the R-C filter (such as the current value of the filter signal FS), QC_now is the current charge of the capacitor of the R-C filter, OUT_pre is the previous value of the output signal of the R-C filter (such as the filter signal FS), QC_pre is the previous charge of the capacitor of the R-C filter FLOW is the amount of path charge, and Damp is the amount of attenuation.

………………………（式2）

…………………… (Formula 2)

………………（式3）

…………… (Formula 3)

…………………………（式4）

……………………… (Formula 4)

In some embodiments, the filter may have a signal gain circuit, a signal attenuation circuit, a comparator, and an integrator (eg, an R-C integrator) to assist in the filtering process. For example, the rectified signal RS is input to the comparator for comparison with the feedback signal, and the comparison result is sequentially processed by the signal gain circuit, the integrator and the signal attenuation circuit (for example, the signal gain circuit performs signal gain processing, the integrator Integral processing, signal attenuation circuit for signal attenuation processing) output the feedback signal to the comparator for the next comparison of the rectified signal RS. When there is a steady state between the rectified signal RS and the feedback signal, the processor 14 uses the feedback signal as the filtered signal FS. In some embodiments, the processor 14 selectively generates different steering information according to the positive and negative values of the filter signal FS. For example, if the filtered signal FS is positive, the steering information of “forward rotation” will be generated, and if the filtered signal FS is negative, the steering information of “reverse rotation” will be generated. To further illustrate, as shown in FIG. 5 , since the proportion of the positive value of the rectified signal RS is greater than that of the negative value, after the integral operation, the filtered signal FS is all positive. As shown in FIG. 6 , since the proportion of negative values of the rectified signal RS is greater than that of positive values, the filtered signal FS is all negative after the integral operation. Therefore, by judging whether the filter signal FS is positive or negative, it can be judged whether the rotor 20 of the motor 11 is rotating forward or reversely.

Referring to FIG. 7 , FIG. 7 is a schematic diagram of a motor steering detection system 10 according to some embodiments of the present invention. In the following, the induced electromotive force detector 13 is electrically connected to the coil 31U as an example for illustration. The Hall sensor 12 and the coil 31U are respectively located on a different first axis L1 and a second axis L2 passing through the stator 30 and the rotor 20 . Specifically, the axes L1-L2 pass through the stator 30 and the rotor 20, the Hall sensor 12 is located on the first axis L1, the coil 31U is located on the second axis L2, and the first axis L1 is different from the second axis L2. That is to say, as shown in FIG. 7, assuming that the stator 30 is preset with three positions A~C for the Hall sensor 12 to set, the Hall sensor 12 can be set at positions A and B instead of being set at The position C, because the position C and the coil 31U are both located on the second axis L2 (more specifically described below).

Refer to FIG. 8 and FIG. 9 . FIG. 8 shows the application of the Hall sensor 12 of the first embodiment of the present invention, the Hall voltage signal HV and the induced electromotive force signals BEMF_U~BEMF_W. FIG. 9 shows the application of the Hall sensor 12 , the Hall voltage signal HV and the induced electromotive force signals BEMF_U~BEMF_W of the second embodiment of the present invention. In the first embodiment, the rotor 20 of the motor 11 is rotating forward, and in the second embodiment, the rotor 20 of the motor 11 is rotating in reverse. The induced electromotive force signals BEMF_U˜BEMF_W are generated by the induced electromotive force detector 13 respectively detecting the coils 31U˜31W. Since the magnetic flux between the coils 31U~31W of the motor 11 will influence each other, a positive half wave with double peaks is formed in the induced electromotive force signals BEMF_U~BEMF_W, and there is a lowest point between the double peaks (hereinafter referred to as symmetry) point D_U~D_W). The symmetry points D_U˜D_W respectively occur at the magnetic junctions of the coils 31U˜31W corresponding to the rotor 20 , and the single positive half-wave in the induced electromotive force signals BEMF_U˜BEMF_W is symmetrical due to the symmetry points D_U˜D_W.

In some embodiments, since the processor 14 performs an integral operation by rectifying the magnitude of the positive ratio and the magnitude of the negative ratio of the rectified signal RS, to generate the filtered signal FS. When the coil induced by the induced electromotive force detector 13 is on the same axis as the Hall sensor 12 (for example, as shown in FIGS. 8 and 9 , the coil 31W is on the same axis as the Hall sensor 12), the induced electromotive force The symmetrical point of the signal (for example, as shown in Figure 8 and Figure 9, the symmetrical point D_W of the induced electromotive force signal BEMF_W) is located at the junction between the high level and the low level of the Hall voltage signal HV, so the rectified signal RS The positive ratio is the same as the negative ratio, so that the processor 14 cannot generate an accurate filtered signal FS (for example, the filtered signal FS is zero and has no positive or negative values). Therefore, as shown in FIG. 7, the Hall sensor 12 and the coil 31U are respectively located on different first axes L1 and second axes L2 passing through the stator 30 and the rotor 20 (for example, the Hall sensor 12 is arranged on position A, B, instead of being set at position C located on the second axis L2).

As shown in FIG. 7 , the following takes the induced electromotive force detector 13 electrically connected to the coil 31U as an example for description. In some embodiments, the distance DD between the Hall sensor 12 and the coil 31U is not greater than a position threshold, wherein the position threshold is when the first axis intersects the second axis L2 and the angle between them is a right angle. , the value of the distance between the Hall sensor 12 and the coil 31U. For example, assuming that the first axis is L3, the first axis L3 intersects the second axis L2 and the angle between them is a right angle, if the Hall sensor 12 is located on the first axis L3, and the coil 31U is located on the second axis L2, when the coil 31U is located at an electrical angle of 0 degrees, the Hall sensor 12 is located at an electrical angle of 90 degrees or an electrical angle of 270 degrees. At this time, the rectified signal RS and the filtered signal FS respectively have the best rectification effect and filter effects. In addition, when the coil 31U is located at an electrical angle of 0 degrees, the rectification effect and filtering effect of the Hall sensor 12 located at an electrical angle of 0-90 degrees or 270-360 degrees are better than those located at an electrical angle of 90-90 degrees. The rectification and filtering effects of the 270-degree Hall sensor at 12 o'clock. Due to the process factors of some motors 11, it may not be possible to set the Hall sensor 12 at an electrical angle of 90 degrees or an electrical angle of 270 degrees, so the distance DD between the Hall sensor 12 and the coil 31U is not greater than The position threshold (that is, in the case that the coil 31U is located at an electrical angle of 0 degrees, the Hall sensor 12 is located at an electrical angle of 0~90 degrees or 270~360 degrees), so as to retain a better rectification effect and In addition to the filtering effect, it can meet the manufacturing process of the motor 11 .

Refer to Figure 1 and Figure 10. FIG. 10 is a schematic diagram of a driving circuit 16 according to some embodiments of the present invention. In some embodiments, the motor steering detection system 10 further includes a driving circuit 16 . The driving circuit 16 is electrically connected between the processor 14 and the motor 11 . The driving circuit 16 is used to drive the motor 11 to operate. For example, the driving circuit 16 responds to the driving signal DS from the processor 14, and turns on the first transistor M1, the fifth transistor M5 and the sixth transistor M6, or turns on the second transistor M2, the third transistor M3 and the The fourth transistor M4 is used to operate the motor 11 after generating the phase voltage. In some embodiments, the processor 14 generates the driving signal DS according to the steering information, so as to control the motor 11 through the driving circuit 16 to perform corresponding forward rotation or reverse rotation.

To sum up, according to some embodiments, the rotation direction of the motor can be determined through the Hall sensors, the induced electromotive force detectors and their locations, thereby reducing the number of required Hall elements. According to some embodiments, since the induced electromotive force detector can have a simple circuit structure, the manufacturing cost and the complexity of the circuit design can be reduced.

10: Motor steering detection system

11: Motor

20: rotor

30: stator

31U~31W: Coil

12: Hall sensor

13: Induction electromotive force detector

14: Processor

16: Drive circuit

HV: Hall voltage signal

BEMF, BEMF_U~BEMF_W: induced electromotive force signal

DS: drive signal

R1: the first voltage divider resistor

R2: The second voltage divider resistor

ND: output node

GND: reference ground

MF: curve

RS: rectified signal

FS: filter signal

L1, L3: the first axis

L2: second axis

A~C: position

DD: distance

D_U~D_W: symmetrical point

M1~M6: Transistor

S100~S104: steps

[FIG. 1] is a schematic diagram of a motor steering detection system according to some embodiments of the present invention. [ FIG. 2 ] is a schematic flow chart of a steering detection method according to some embodiments of the present invention. [ FIG. 3 ] is a schematic diagram of the rotor and the induced electromotive force detector of some embodiments of the present invention. [ FIG. 4 ] is a schematic diagram of the induced electromotive force signal and the magnetic flux change of the coil caused by the rotor in some embodiments of the present invention. [ FIG. 5 ] is a schematic diagram of the Hall voltage signal, the induced electromotive force signal, the rectified signal and the filtered signal according to the first embodiment of the present invention. [ FIG. 6 ] is a schematic diagram of the Hall voltage signal, the induced electromotive force signal, the rectified signal and the filtered signal according to the second embodiment of the present invention. [ FIG. 7 ] is a schematic diagram of a motor steering detection system according to some embodiments of the present invention. [ Fig. 8 ] is the Hall sensor application, Hall voltage signal and induced electromotive force signal of the first embodiment of the present invention. [Fig. 9] is the Hall sensor application, Hall voltage signal and induced electromotive force signal of the second embodiment of the present invention. [ FIG. 10 ] is a schematic diagram of a driving circuit of some embodiments of the present invention.

10: Motor steering detection system

11: Motor

20: rotor

30: stator

31U~31W: Coil

12: Hall sensor

13: Induction electromotive force detector

14: Processor

16: Drive circuit

HV: Hall voltage signal

BEMF: induced electromotive force signal

DS: drive signal

Claims (8)

A motor steering detection system, comprising: a motor with a stator and a rotor, the stator has a coil; a Hall sensor, used to induce a magnetic field of the rotor to generate a Hall voltage signal, wherein the Hall the sensor and the coil are respectively located on a different first axis and a second axis passing through the stator and the rotor; an induced electromotive force detector is used to detect the coil to generate an induced electromotive force signal; and A processor for: rectifying the induced electromotive force signal according to the Hall voltage signal to generate a rectified signal; filtering the rectified signal to generate a filtered signal; and generating steering information according to the filtered signal, For judging the steering of the motor; wherein, the distance between the Hall sensor and the coil is not greater than a position threshold, wherein the position threshold is between the intersection of the first axis and the second axis When the included angle is a right angle, the value of the distance between the Hall sensor and the coil. The motor steering detection system as described in claim 1, wherein the processor maintains the induced electromotive force signal when the Hall voltage signal is at a high level, and maintains the induced electromotive force signal when the Hall voltage signal is at a low level. The induced emf signal is converted to a negative value, thereby producing the rectified signal. The motor steering detection system as described in claim 1, wherein the induced electromotive force detector includes a first voltage dividing resistor, a second voltage dividing resistor and an output node, the output The node is located between the first voltage dividing resistor and the second voltage dividing resistor, wherein when the magnetic flux of the coil changes, the coil generates a current in the first voltage dividing resistor and the second voltage dividing resistor, and the first voltage dividing resistor A voltage dividing resistor and the second voltage dividing resistor output the induced electromotive force signal at the output node according to the current. The motor steering detection system as claimed in claim 1, wherein the processor selectively generates different steering information according to the positive and negative values of the filtered signal. A steering detection method suitable for a motor, a Hall sensor, an induced electromotive force detector and a processor, the motor has a stator and a rotor, the stator has a coil, the steering detection method includes : According to a Hall voltage signal, an induced electromotive force signal is rectified to generate a rectified signal, wherein the Hall voltage signal is generated by the Hall sensor sensing the rotor's magnetic field, and the induced electromotive force signal is generated by the The induced electromotive force detector is generated by detecting the coil, and the Hall sensor and the coil are respectively located on a different first axis and a second axis passing through the stator and the rotor; filtering the rectified signal, and generate a filter signal; and according to the filter signal, generate a steering information for judging the steering of the motor, wherein the distance between the Hall sensor and the coil is not greater than a position threshold, wherein the position threshold is When the first axis intersects the second axis and the angle between them is a right angle, the value of the distance between the Hall sensor and the coil. The steering detection method as described in claim 5, wherein the induced electromotive force signal is maintained when the hall voltage signal is at a high level, and the induced electromotive force signal is maintained when the hall voltage signal is at a low level Converted to a negative value, resulting in the rectified signal. The steering detection method as described in claim 5, wherein the induced electromotive force detector includes a first voltage dividing resistor, a second voltage dividing resistor and an output node, and the output node is located between the first voltage dividing resistor and Between the second voltage-dividing resistor, when the magnetic flux of the coil changes, the coil generates a current in the first voltage-dividing resistor and the second voltage-dividing resistor, and the first voltage-dividing resistor and the second voltage-dividing resistor The piezoresistor outputs the induced electromotive force signal at the output node according to the current. The steering detection method as claimed in claim 5, wherein the processor selectively generates different steering information according to the positive and negative values of the filtered signal.

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