JP2019126244A - Motor controller and control method - Google Patents

Abstract

To restrain the impact of magnetic flux from a yoke on the changeover of electrification direction.SOLUTION: First magnetic pole part 6a of a first yoke 6 and second magnetic pole part 7a of a second yoke 7 face the outer peripheral surface of a rotor 3 and are placed by shifting the electrical angle for the magnetization phase of a magnet 2, and faces the outer peripheral surface of the rotor 3. A first coil 4 magnetizes the first magnetic pole part 6a, and a second coil 5 magnetizes the second magnetic pole part 7a. A control circuit 13 controls the electrification direction to the coils 4, 5, on the basis of comparison result signals 400, 401 indicating comparison result of output signals 10b, 11b from comparators 200, 201 and reference signals 300, 301. The control circuit 13 changes the values of the reference signals 300, 301 according to the relation of the polarity of the first magnetic pole part 6a and the polarity of the second magnetic pole part 7a.SELECTED DRAWING: Figure 11

Description

  The present invention relates to a motor control device and method.

  The stepping motor has features such as small size, high torque, and long life, and can easily realize digital positioning operation by open loop control, widely used in home information appliances such as cameras and optical disk devices, and OA equipment such as printers and projectors. It is used. However, when the motor is rotated at high speed or when the load on the motor is large, the motor may be out of step, and there is a problem that the efficiency is lower than that of the brushless motor or the DC motor. In order to solve this problem, it is known to prevent the step out by mounting an encoder on the stepping motor and switching the energization according to the position of the rotor, thereby performing a so-called brushless DC motor operation.

  Patent Document 1 discloses a motor control device that detects the position of a rotor by a magnetic sensor and sequentially switches energization of a coil. In the device of Patent Document 1, the magnetic sensor is disposed such that the excitation switching timing is between 0 and 45 degrees of electrical advance, and the excitation switching timing is disposed between 45 and 90 degrees of electrical advance. And a magnetic sensor provided on the motor. Also, the magnets of the rotor are magnetized in multiple poles such that N and S poles alternate in the circumferential direction. And the apparatus of patent document 1 detects the switch of the north-pole and the south pole of the magnet according to rotation with a magnetic sensor, and is switching the electricity supply to a coil one by one.

JP, 2014-128143, A

  Originally, as for a magnetic sensor, it is desirable to detect only the magnetic flux from the magnet which a rotor has. However, depending on the energized state of the two coils, the magnetic sensor may also detect the magnetic flux from the yoke. Then, the switching between the north pole and the south pole of the magnet can not be accurately detected, and there is a possibility that a time lag may occur from the timing of switching the current supply to the intended coil. Due to this temporal deviation, there is a problem that the actual generated torque deviates from the intended generated torque.

  An object of the present invention is to suppress the influence of the magnetic flux from the yoke on the switching of the energization direction.

  In order to achieve the above object, the present invention provides a rotatable rotor which is formed in a cylindrical shape and is provided with a magnet which is divided into a plurality of pieces in the circumferential direction and is alternately multipolar-magnetized to different poles. A first yoke provided with a first magnetic pole opposed to the outer peripheral surface, and a second magnetic pole arranged at a position which is opposed to the outer peripheral surface of the rotor and shifted in electrical angle with respect to the first magnetic pole portion , A first coil which excites the first magnetic pole part by being energized, a second coil which excites the second magnetic pole part by being energized, the second coil A motor control device for controlling a motor having a magnetic sensor disposed opposite to the outer peripheral surface of a rotor and outputting a signal according to magnetic flux, wherein a comparison result between an output signal of the magnetic sensor and a reference signal And a comparator that outputs a comparison result signal indicating Control means for controlling the direction of current supply to the first coil and the second coil based on the comparison result signal output by the comparator, the polarity of the first magnetic pole portion, and the second magnetic pole portion And changing means for changing the value of the reference signal in accordance with the relationship with the polarity of.

  According to the present invention, it is possible to suppress the influence of the magnetic flux from the yoke on the switching of the current supply direction.

It is a block diagram of a motor control device. It is an external appearance perspective view of a motor. It is a figure which shows the relationship of the rotation angle of a rotor, and a torque of a motor when a fixed electric current is sent to a coil. FIG. 5 is a cross-sectional view of the motor in a direction perpendicular to the axis showing the phase relationship between the respective yokes and the magnet. It is a figure which shows the motor torque generate | occur | produced by the electricity supply state of the 1st, 2nd coil with respect to the rotation angle of a rotor. It is sectional drawing ((a), (c), (d)) which represented the positional relationship of the yoke, the magnetic sensor, and the magnet typically, and it is an enlarged view ((b)) of a magnetic sensor. It is a figure which shows the relationship between a magnetic force line and the output signal of a magnetic sensor. It is a figure which shows the relationship between the rotation position of the rotor at the time of right rotation, the energization polarity of a coil, and an output signal. It is a schematic diagram of a 1st comparator and a 2nd comparator. It is a figure which shows the relationship between the rotation position of the rotor at the time of right rotation, the polarity of the applied voltage of a coil, the magnetic pole of a magnetic pole part, and the setting value of a reference signal. It is a figure which shows the relationship between the rotation position of the rotor at the time of right rotation, the energization polarity of a coil, and an output signal. It is a flowchart of reference signal setting processing. It is a figure which shows a comparison result signal. It is a figure which adds and shows a comparison result signal to the relationship between the rotation position of the rotor at the time of right rotation, the energization polarity of a coil, and an output signal. FIG. 16 is a diagram showing a comparison result signal added to the relationship between the rotational position of the rotor at the time of right rotation, the energization polarity of the coil, and the output signal when the magnetic sensor is disposed in the lead phase. It is a flowchart of waiting time setting processing.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First Embodiment
FIG. 1 is a block diagram of a motor control device according to a first embodiment of the present invention. FIG. 2 is an external perspective view of the motor. In FIG. 2, some parts are broken and shown for the facilities of description. The motor control device includes a motor 1, a drive circuit 22, and a control circuit 13. The control circuit 13 as a control means includes a CPU, a ROM, and a RAM (all not shown). The motor 1 includes a rotor 3, a first coil 4, a first yoke 6, a second coil 5, and a second yoke 7. The motor 1 further includes a first magnetic sensor 10 (first magnetic sensor), a second magnetic sensor 8, a third magnetic sensor 11 (second magnetic sensor), and a fourth magnetic sensor 9. The control circuit 13 includes a reference signal changing unit 500, and comparators 200, 201, 202, and 203 connected to the reference signal changing unit 500, respectively. Comparators 200, 202, 201, and 203 are connected to the magnetic sensors 10, 8, 11, and 9, respectively.

  The rotor 3 includes a magnet 2 and is rotatably controlled by a control circuit 13 via a drive circuit 22. The magnet 2 is formed in a cylindrical shape, and the outer peripheral surface is divided into a plurality of pieces in the circumferential direction, and multipole magnetization is alternately performed on different poles. In the present embodiment, the magnet 2 is magnetized in eight divisions, that is, in eight poles (four N poles and four S poles). In addition, you may magnetize not only in 8 poles but 2 poles, 4 poles, 12 poles or more, for example.

  The first coil 4 is disposed on one end side of the magnet 2 in the axial direction. The first yoke 6 is a soft magnetic material, and is formed to face the outer peripheral surface of the magnet 2 with a gap. The first yoke 6 includes a plurality of first magnetic pole portions 6 a facing the outer peripheral surface of the magnet 2. The plurality of first magnetic pole portions 6 a axially extend from the annular main body portion of the first yoke 6 and are arranged at predetermined intervals in the circumferential direction. The first magnetic pole portion 6 a is excited by energization of the first coil 4. A "first stator unit" is configured by the first coil 4, the first yoke 6, and the magnets 2 opposed to the plurality of first magnetic pole portions 6a.

  The second coil 5 is disposed at the other end opposite to the one end in the axial direction to which the first coil 4 of the magnet 2 is attached. The second yoke 7 is formed of a soft magnetic material and is opposed to the outer peripheral surface of the magnet 2 with a gap. The second yoke 7 includes a plurality of second magnetic pole portions 7 a facing the outer peripheral surface of the magnet 2. The plurality of second magnetic pole portions 7a axially extend from the annular main body portion of the second yoke 7 and are arranged at predetermined intervals in the circumferential direction. The second magnetic pole portion 7 a is excited by energization of the second coil 5. The second magnetic pole portion 7 a is disposed at a phase different from the relative phase between the first yoke 6 and the magnet 2. A "second stator unit" is configured by the second coil 5, the second yoke 7, and the magnets 2 facing the plurality of second magnetic pole portions 7a.

  The control circuit 13 can change the torque given to the rotor 3 by switching the poles (N pole, S pole) excited to each of the first magnetic pole portion 6 a and the second magnetic pole portion 7 a. The control circuit 13 applies a voltage of the same magnitude when the first coil 4 and the second coil 5 are energized. The coils and the yokes are designed such that the first magnetic pole 6a and the second magnetic pole 7a have the same strength when a voltage of the same magnitude is applied. The first magnetic sensor 10, the second magnetic sensor 8, the third magnetic sensor 11, and the fourth magnetic sensor 9 are all Hall elements for detecting the magnetic flux of the magnet 2 and are fixed to the motor cover 12. When the rotor 3 makes one rotation, each magnetic sensor alternately detects the N pole and the S pole of the magnet 2 and outputs a signal indicating eight poles. Thus, the rotational position of the rotor 3 can be detected. The motor cover 12 is configured such that the first yoke 6 and the first magnetic pole portion 6 a and the second magnetic pole portion 7 a are disposed so as to be shifted by approximately 90 degrees in electrical angle with respect to the magnetization phase of the magnet 2. The two yokes 7 are fixed and held. Here, the electrical angle represents one cycle of the magnet magnetic force as 360 °, and assuming that the number of poles of the rotor is M and the mechanical angle is θ0, the electrical angle θ can be expressed by the following equation 1.

θ = θ0 × M / 2 (1)
In the present embodiment, since the magnetization of the magnet 2 has eight poles, 90 degrees of the electrical angle is 22.5 degrees in the mechanical angle. In the following description, the operation of the feedback energization switching mode will be described mainly using the electrical angle.

  FIG. 3 is a view showing the relationship between the rotation angle of the rotor 3 and the torque of the motor 1 when a constant current is supplied to the coil of the motor 1, and the horizontal axis represents the electrical angle and the vertical axis represents the motor torque. . For positive and negative motor torques, the torque for rotating the rotor 3 clockwise in FIG. 1 and FIG. 4 is positive.

  FIGS. 4A and 4B are cross-sectional views of the motor 1 in the direction perpendicular to the axis, showing the phase relationship between the respective yokes and the magnet 2. In the present embodiment, the first magnetic pole portion 6 a is magnetized to the N pole when a current in the positive direction flows through the first coil 4, and the second magnetic pole portion when a current in the positive direction flows through the second coil 5. Suppose that 7a is magnetized to the N pole.

  The phase of the state of FIG. 4 (a) is shown as a in FIG. In FIG. 4A, the distance between the center of the magnetized pole of the magnet 2 and the center of the first magnetic pole portion 6a in the circumferential direction is the distance between the center of the pole and the second magnetic pole portion 7a in the circumferential direction Is the same as In the state of FIG. 4A, a force for holding the rotational phase (rotational position) is generated, but the S pole of the magnet 2 is the N pole of the first magnetic pole portion 6a and the N pole of the second magnetic pole portion 7a. No rotational driving force is generated because it is attracted to the pole and balanced.

  When the second magnetic pole portion 7a is switched from the state of FIG. 4 (a) and excited to the S pole, the rotor 3 rotates until it becomes the state shown in FIG. 4 (b). In the state of FIG. 4B, a force for holding the rotational phase is generated as in the state shown in FIG. 4A, but no rotational driving force is generated. That is, with the S pole of the magnet 2 being attracted to the N pole of the first magnetic pole portion 6 a and the N pole of the magnet 2 being attracted to the S pole of the second magnetic pole portion 7 a of the second yoke, is there. In the same manner, the rotor 3 is rotated by sequentially switching the energization directions of the first coil 4 and the second coil 5 and switching the polarities of the first magnetic pole portion 6a and the second magnetic pole portion 7a. Can go.

  Switching the poles excited in the first magnetic pole portion 6a and the second magnetic pole portion 7a at such a timing that the rotational driving force is not generated is defined as energization switching at an electrical advance angle of 0 degrees. Switching of the pole excited in the first magnetic pole part 6a and the second magnetic pole part 7a at a timing earlier than this timing by the electrical angle γ degree is defined as excitation switching of the magnetic pole portion at the electrical advance angle γ degree Do.

  5 (a) to 5 (c) are diagrams showing the motor torque generated by the energized state of the first coil 4 and the second coil 5 with respect to the rotation angle of the rotor 3 on the vertical axis. The electrical angle is taken on the horizontal axis.

  The curve L1 shows the motor torque in the case where the energization direction to the first coil 4 is positive and the energization direction to the second coil 5 is positive. The curve L2 shows the motor torque in the case where the current supply direction to the first coil 4 is positive and the current supply direction to the second coil 5 is reverse. The curve L3 shows the motor torque in the case where the current supply direction to the first coil 4 is reverse and the current supply direction to the second coil 5 is reverse. A curved line L4 indicates a motor torque when the current supply direction to the first coil 4 is reverse and the current supply direction to the second coil 5 is positive.

  FIG. 5A shows the state when the electrical advance angle is 0 degree. When the coil conduction direction is switched at such timing, the phase immediately before switching the conduction direction is extremely small as the output of the motor 1 because the motor torque is extremely small as shown by the hatched portions and thick lines. It does not. FIG. 5 (b) shows the state when the electrical advance angle is 45 degrees. At an electrical advance angle of 45 degrees, the motor torque generated when switching the energization direction is maximum. In addition, when the switching timing is advanced, and the energization direction of the coil is switched at an electrical advance angle of 90 degrees, it becomes as shown by the hatched portion in FIG. 5C, and as a result, the same result as the case of an electrical advance angle of 0 degrees Therefore, a large rotational driving force can not be obtained.

  As described above, the motor torque is maximized when the electrical advance angle is 45 degrees. When it is desired to decrease the motor torque, the electric advance angle may be shifted from 45 degrees to be close to 0 degrees or 90 degrees, for example, changed according to a desired torque to be obtained, such as 45 degrees or 50 degrees. In addition, even if the energization of the coil is switched, the current does not instantaneously switch to the predetermined current value, and the current gradually approaches the predetermined current value while gradually increasing. In some cases, it is possible to obtain the largest torque by advancing the electrical advance angle by 45 degrees, for example, by advancing the electrical angle by 24 degrees, in consideration of the transient response of the current.

  Next, the influence of the polarity of the magnetic pole part on the magnetic sensor will be described. In the present embodiment, the position of the rotor 3 is detected by the magnetic sensors 8-11, and a desired electrical advance angle is obtained by the arrangement positions of the magnetic sensors 8-11.

  6A, 6C, and 6D are cross-sectional views schematically showing the positional relationship between the yoke, the magnetic sensor, and the magnet. FIG. 6 (b) is an enlarged view of the magnetic sensor. FIG. 7 is a diagram showing the relationship between magnetic lines of force and the output signal of the magnetic sensor. Each of the magnetic sensors 8 to 11 is located between the first magnetic pole portion 6 a and the second magnetic pole portion 7 a in the axial direction of the magnet 2 (the phase is different). All of the magnetic sensors 8 to 11 are arranged on the outer peripheral side in the radial direction of the magnet 2 than the first magnetic pole portion 6a and the second magnetic pole portion 7a. More specifically, although the central positions of the magnetic pole portions 6a and 7a are the same in the radial direction of the magnet 2, the central positions of the magnetic sensors 8 to 11 (or the positions of the magnetic flux detection portions) are more than these positions. Is located on the outer peripheral side. The arrangement of the magnetic sensors 8 to 11 may be forced to be such because of the arrangement relationship with other parts and the restriction of industrial accuracy.

  Description will be given focusing on the first magnetic sensor 10 as a representative. The first magnetic sensor 10 using a Hall element internally includes a magnetic flux detection unit 10a that detects magnetism (FIG. 6 (b)). In the example of FIG. 6 (a), the polarity of the first magnetic pole 6a of the first yoke 6 and the polarity of the second magnetic pole 7a of the second yoke 7 are both N-polar when the coils 4 and 5 are energized. It has become. The magnet 2 of the rotor 3 is in a state in which the portion of the south pole approaches by being attracted to the north pole.

  The first magnetic sensor 10 outputs the first output signal 10b (FIGS. 8A and 9A) as a signal corresponding to the magnetic flux detected by the magnetic flux detection unit 10a, and the third magnetic sensor 11 similarly outputs the same. Outputs the second output signal 11b (FIG. 8 (b), FIG. 9 (b)). As shown in FIG. 7, when the magnetic flux detection unit 10 a detects magnetic lines representing the direction of the S pole from the N pole toward the upper side (the outer peripheral direction in the radial direction of the magnet 2) of FIG. Outputs a + (plus) voltage as the output signal 10 b. Conversely, when the magnetic flux detection unit 10a detects a magnetic line representing the direction of the S pole from the N pole toward the lower side (the inner circumferential direction in the radial direction of the magnet 2) of FIG. 6B, the first magnetic sensor 10 outputs As a signal 10b, a voltage of-(minus) is output. The first magnetic sensor 10 has a characteristic that the magnitude of the voltage also changes according to the magnitude of the magnetic force, and outputs a large voltage in the case of a large magnetic force and outputs a small voltage in the case of a small magnetic force.

  The magnetic flux detection unit 10a is provided to detect the magnetic flux in the radial direction (vertical direction in FIG. 6B) from the magnet 2, but also detects the magnetic flux from the magnetic pole portions 6a and 7a of the yokes 6 and 7 Resulting in. When the magnetic pole parts 6a and 7a are both N poles, as shown in FIG. 6A, magnetic lines of force 100 that repel between the magnetic pole parts 6a and 7a are generated. If the magnetic flux detection unit 10a can be disposed at a point (for example, the central position of the magnetic pole portions 6a and 7a in the radial direction of the magnet 2) where the magnetic force lines 100 are in a direction orthogonal to the radial direction (left and right direction in FIG. The magnetic lines of force 100 from the sections 6a and 7a are never detected. However, as mentioned above, it is difficult to realize such an arrangement due to various constraints.

  In the example of FIG. 6A, since the magnetic flux detection unit 10a is disposed on the outer peripheral side from the point where the magnetic force lines 100 are not detected, the magnetic force lines 100 are located at the position of the magnetic flux detection unit 10a as shown in FIG. It will be facing the outer circumference. Since the first magnetic sensor 10 detects the magnetic flux 100 toward the outer periphery from the yokes 6 and 7 in addition to the magnetic flux of the magnet 2, the output signal 10 b output by the first magnetic sensor 10 has a ratio compared to that in the absence of the magnetic flux 100. Shift to the + (plus) side.

  On the other hand, in the example of FIG. 6C, the magnetic poles of both of the magnetic pole parts 6a and 7a become the south poles by energization of the coils 4 and 5. In this case, the lines of magnetic force 100 are directed from the upper and lower sides of FIG. 6C toward the magnetic pole portions 6a and 7a, and the lines of magnetic force 100 are directed downward at the position of the magnetic flux detection unit 10a. Since the first magnetic sensor 10 detects the magnetic line 100 directed inward from the yokes 6 and 7 in addition to the magnetic flux of the magnet 2, the output signal 10 b output from the first magnetic sensor 10 does not have the magnetic line 100. In comparison, shift to the-(minus) side.

  In the example of FIG. 6 (d), the first and second magnetic pole portions 6a and 7a have the N pole and the S pole, respectively, when the coils 4 and 5 are energized. It is the same. The magnetic lines of force 100 are directed in the left and right direction in FIG. In such a state, even if the position of the magnetic sensor 10 is somewhat deviated in the radial direction, the influence of the magnetic field lines 100 on the output signal 10b of the first magnetic sensor 10 is small. Similarly, even when the first and second magnetic pole portions 6a and 7a have the S pole and the N pole, respectively, when the coils 4 and 5 are energized, the lines of magnetic force 100 are directed in the direction of lower sensitivity to the magnetic sensor 10. Therefore, the influence on the output signal 10b is small. That is, in the case where the polarities of the magnetic pole portions 6a and 7a are different, the magnetic force lines 100 are directed in the direction in which the sensitivity of the magnetic sensor 10 is low, so the influence on the output signal 10b is small.

  The respective magnetic flux detection units of the other magnetic sensors 8, 9 and 11 are also disposed on the outer peripheral side than the location where the magnetic field lines 100 are not detected, so their output signals have the same tendency as those of the first magnetic sensor 10. Indicates

  8 (a) and 8 (b) show the rotational position of the rotor 3 and the energization polarity of the coil and the output signal in the case of rotating the rotor 3 clockwise (rotation in the clockwise direction in FIGS. 4 (a) and 4 (b)). FIG. In particular, FIG. 8A shows an output signal of the first magnetic sensor 10, and FIG. 8B shows an output signal of the third magnetic sensor 11. As disclosed in Patent Document 1, it is possible to obtain various generated torques by changing the correspondence between the coil for switching the energization polarity and the magnetic sensor. In the present embodiment, energization of the first coil 4 is switched based on the first magnetic sensor 10, and energization of the second coil 5 is switched based on the third magnetic sensor 11 to drive the motor 1.

  The rotational position of the rotor 3 is taken on the horizontal axis of FIGS. 8A and 8B, and 360 degrees of one rotation of the rotor 3 is shown. The vertical axis shows the waveform of the output signal, and the upper side is a positive voltage side when detecting the N pole, and the lower side is a negative voltage side signal when detecting the S pole. On the lower side of FIGS. 8A and 8B, energization polarities (+,-) of the coil and magnetic poles (N, S) of the magnetic pole portions 6a and 7a of the yokes 6 and 7 are described. In FIG. 8A, the first output signal 10b of the magnetic flux detection unit 10a of the first magnetic sensor 10 is indicated by a thick solid line, and in FIG. 8B, the second output signal of the third magnetic sensor 11 is detected. The output signal 11b of is indicated by a thick solid line. The thin solid line indicates waveforms 10r and 11r of an ideal output signal which is not affected by the magnetic flux of the magnetic pole portions 6a and 7a. The control circuit 13 changes the magnetic poles of the magnetic pole portions 6a and 7a by switching the conduction polarity of the coils 4 and 5 each time the corresponding output signal passes through zero.

  As described above, when the polarities of the two magnetic pole portions 6a and 7a are different from each other, the magnetic field lines 100 generated thereby hardly substantially affect the output signals 10b and 11b of the magnetic sensors 10 and 11. However, when a positive (plus) voltage is applied to both coils 4 and 5, the corresponding magnetic pole parts 6a and 7a both become N poles, and both of the output signals 10b and 11b are on the positive side (FIG. 8). Offset to the N side of the vertical axis of The offset output signals 10 b and 11 b have waveforms 10 (+) and 11 (+) indicated by broken lines, and the offset amount thereof is about +0.3 V. Conversely, when a negative (-) voltage is applied to both coils 4 and 5, the corresponding magnetic pole portions 6a and 7a both become S poles, and both of the output signals 10b and 11b are on the negative side (FIG. 8). Offset to the S axis of the middle vertical axis). The offset output signals 10 b and 11 b have waveforms 10 (−) and 11 (−) indicated by broken lines, and the offset amount is about −0.3 V.

  Next, problems due to driving in the prior art will be described. As an example, the case where the rotational position of the rotor 3 is in the rotational direction from 0 degrees to 180 degrees and then 360 degrees, that is, right rotation will be described. The control circuit 13 switches the energization direction of the first coil 4 every 45 degrees every time the rotational position of the rotor 3 becomes 22.5 degrees, 67.5 degrees, and 112.5 degrees in mechanical angle. Suppose that it intended to drive. In addition, the control circuit 13 intends to drive the switching direction of the second coil 5 every 45 degrees every time the rotational position of the rotor 3 becomes 0 degree, 45 degrees, and 90 degrees in mechanical angle. I assume.

  Assuming that the prior art is used, if the output signal 10b of the first magnetic sensor 10 is positive, the conduction polarity of the first coil 4 is positive, and if the output signal 10b is negative, the conduction polarity of the coil 4 is negative. Drive, and the polarity of the magnetic pole of the first magnetic pole portion 6a is also changed accordingly. Similarly, when the output signal 11b of the third magnetic sensor 11 is positive, the conduction polarity of the second coil 5 is positive, and when the output signal 11b is negative, the conduction polarity of the coil 5 is negative. Accordingly, the polarity of the magnetic pole of the second magnetic pole portion 7a is also changed.

  Here, from the state of the rotational position of 22.5 degrees of the rotor 3, the timing of the positive / negative switching of the voltage of the output signals 10b and 11b and the coils 4 and 5 will be observed. Then, at the moment of 22.5 degrees, both the coil 4 and the coil 5 have a negative voltage, and both the magnetic pole portion 6a and the magnetic pole portion 7a have an S pole. As a result, the output signals 10 b and 11 b respectively pass through the waveform 10 (−) and the waveform 11 (−) on the negative side. Next, looking at around the rotational position 45 degrees, since the output signal 11b is still negative at the rotational position 45 degrees, positive and negative switching of the voltage does not occur. The output signal 11b becomes zero at 48.75 degrees, which is 3.75 degrees after the rotational position 45 degrees, and the voltage of the coil 5 switches from negative (-) to positive (+). This delay of 3.75 degrees (mechanical angle) corresponds to a delay of 15 degrees in the electrical angle.

  As described above, it can be understood that the timing of the energization switching of the coil 5 is delayed by the magnetic flux from the magnetic pole portion 7a. Since the output signal 11b is still on the plus side near the rotational position 90 degrees, the output signal 11b becomes zero at 93.75 degrees, which is 3.75 degrees after the rotational position 90 degrees, and the voltage of the coil 5 is zero here. It switches from positive (+) to negative (-). This delay of 3.75 degrees (mechanical angle) corresponds to a delay of 15 degrees in the electrical angle. Similarly, in energization of the coil 5, any of rotational position 0 degree (360 degrees), 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees, 315 degrees A delay also occurs at the switching timing. As described above, since the magnetic sensor 11 also detects the magnetic flux from the yokes 6 and 7, a time lag occurs with respect to the timing of the intended energization switching to the coil 5.

  On the other hand, when looking at the coil 4, the output signal 10b is affected by the magnetic flux of the magnetic pole portions 6a and 7a. However, immediately before 22.5 degrees, 67.5 degrees, 112.5 degrees, 157.5 degrees, 202.5 degrees, and every 45 degrees thereafter, the magnetic pole portions 6a and 7a are switched at the switching timing. It is in the state of the waveform 10 r where the influence does not reach. Therefore, there is no delay in switching timing. In the above description, the case where the rotor 3 rotates rightward has been described, but in the case of left rotation reverse to this, the timing of the energization switching in the coil 4 is delayed, contrary to the above example. There is no delay in the energization switching timing of 5.

  Next, a driving method in the present embodiment for solving the problem of the delay in the energization timing described above will be described. In the present embodiment, the control circuit 13 changes (corrects) the magnitude of the reference signal to be compared with the output signal in accordance with the relationship between the polarities of the magnetic poles of the magnetic pole portions 6a and 7a, thereby achieving coil timing at the intended timing. Switch the power supply to 4,5. In motor control in the present embodiment, a first magnetic sensor 10, a third magnetic sensor 11, a first comparator 200, and a second comparator 201 are used (FIG. 1). It is not essential to provide the comparators 200 and 201, the second magnetic sensor 8 and the fourth magnetic sensor 9.

  FIGS. 9A and 9B are schematic views of the first comparator 200 and the second comparator 201 incorporated in the control circuit 13, respectively. The first comparator 200 receives the output signal 10 b of the first magnetic sensor 10 and the first reference signal 300 from the reference signal changing unit 500. The first comparator 200 compares the magnitudes of the output signal 10 b and the first reference signal 300, and outputs a Hi signal as a first comparison result signal 400 if the output signal 10 b is larger. On the contrary, if the output signal 10b is not larger than the first reference signal 300, the first comparator 200 outputs a Low signal whose voltage value is smaller than the Hi signal as the first comparison result signal 400. The control circuit 13 determines the polarity of the voltage applied to the first coil 4 in accordance with the first comparison result signal 400. That is, when the first comparison result signal 400 is Hi, the control circuit 13 applies a positive applied voltage to the first coil 4 and sets the polarity of the magnetic pole portion 6 a to the N pole. When the first comparison result signal 400 is Low, the control circuit 13 applies a negative applied voltage to the first coil 4 and sets the polarity of the magnetic pole portion 6 a to the S pole.

  The output signal 11 b of the third magnetic sensor 11 and the second reference signal 301 from the reference signal changing unit 500 are input to the second comparator 201. The second comparator 201 compares the magnitudes of the output signal 11 b and the second reference signal 301, and outputs a Hi signal as a second comparison result signal 401 if the output signal 11 b is larger. On the contrary, if the output signal 11b is not larger than the second reference signal 301, the second comparator 201 outputs a Low signal having a smaller voltage value than the Hi signal as the second comparison result signal 401. The control circuit 13 determines the polarity of the voltage applied to the second coil 5 in accordance with the second comparison result signal 401. When the second comparison result signal 401 is Hi, the control circuit 13 applies a positive applied voltage to the second coil 5, and sets the polarity of the magnetic pole portion 7a to the N pole. When the second comparison result signal 401 is Low, the control circuit 13 applies a negative applied voltage to the second coil 5, and sets the polarity of the magnetic pole portion 7a to the S pole.

  FIG. 10 shows the relationship among the rotational position of the rotor 3 when rotating the rotor 3 to the right, the polarity of the applied voltage of the coils 4 and 5, the magnetic poles of the magnetic pole portions 6a and 7a, and the set values of the reference signals 300 and 301. FIG. FIGS. 11 (a) and 11 (b) are diagrams showing the relationship between the rotational position of the rotor 3 and the energization polarity of the coil and the output signal when the rotor 3 is rotated to the right. In particular, FIG. 11A shows the output signal of the first magnetic sensor 10, and FIG. 11B shows the output signal of the third magnetic sensor 11. In FIGS. 11 (a) and 11 (b), the output signals 10b and 11b are indicated by thick solid lines in the same manner as in FIGS. 8 (a) and 8 (b), and the offset output signals 10b and 11b are represented by dashed waveform 10 (+ And 11 (+), and ideal output signals are shown by waveforms 10r and 11r.

[When the rotor rotational position is 0 degrees to 22.5 degrees]
When the rotor 3 moves from 0 degrees to 22.5 degrees in mechanical angle (0 degrees to 90 degrees in electrical angle), the voltage applied to the coil 4 is positive, and the magnetic pole portion 6a becomes an N pole. ing. The applied voltage of the coil 5 is negative, and the magnetic pole portion 7a is an S pole. At this time, as described in FIG. 6D, the first output signal 10b and the second output signal 11b are not offset. For this reason, the first reference signal 300 is 0 V as in the prior art. Therefore, it becomes possible to switch the polarity of the voltage applied to the first coil 4 from positive to negative (energization switching) at the rotational position of 22.5 degrees (90 degrees in the electrical angle) of the rotor 3 as desired. There is. On the other hand, the second reference signal 301 is at 0 V, but the timing at which the polarity of the coil 5 is reversed (rotation of the second output signal 11 b crosses the second reference signal 301) in the vicinity of 0 ° to 22.5 ° of the rotational position. Timing is not. Therefore, the second reference signal 301 may not be 0 V, and may be, for example, a voltage (-0.3 V) in anticipation of the next step.

[When the rotor rotational position is 22.5 degrees to 45 degrees]
When the rotor 3 moves from 22.5 degrees to 45 degrees in mechanical angle (90 degrees to 180 degrees in electrical angle), the voltage applied to the coil 4 is negative, and the magnetic pole 6a becomes an S pole. ing. The applied voltage of the coil 5 is negative, and the magnetic pole portion 7a is an S pole. Since both of the magnetic pole parts 6a and 7a are S poles, as described in FIG. 6C, the first output signal 10b and the second output signal 11b are offset by 0.3 V on the negative side. Therefore, the second reference signal 301 is set to -0.3V. Thereby, energization switching of the applied voltage of the coil 5 is performed at the rotational position 45 degrees of the rotor 3 as desired.

[When the rotor rotational position is 45 degrees to 67.5 degrees]
When the rotor 3 moves from 45 degrees to 67.5 degrees in mechanical angle (180 degrees to 270 degrees in electrical angle), the voltage applied to the coil 4 is negative, and the magnetic pole portion 6a becomes an S pole. ing. The coil 5 has a positive applied voltage, and the magnetic pole portion 7a has an N pole. As described in FIG. 6 (d), the first output signal 10b and the second output signal 11b are not offset. Therefore, the first reference signal 300 is at 0 V as in the conventional case. Therefore, the polarity of the voltage applied to the first coil 4 can be switched from positive to negative at the rotational position 67.5 degrees (270 degrees in the electrical angle) of the rotor 3 as desired. On the other hand, the second reference signal 301 is 0 V, but the timing to reverse the polarity of the coil 5 in the vicinity of the rotational position 45 degrees to 67.5 degrees (the second output signal 11 b crosses the second reference signal 301 Timing is not. Therefore, the second reference signal 301 may not be 0 V, and may be, for example, a voltage (+0.3 V) in anticipation of the next step.

[When the rotor rotational position is 67.5 degrees to 90 degrees]
When the rotor 3 moves from 67.5 degrees to 90 degrees in mechanical angle (270 degrees to 360 degrees in electrical angle), the voltage applied to the coil 4 is positive, and the magnetic pole portion 6a becomes an N pole. ing. The coil 5 has a positive applied voltage, and the magnetic pole portion 7a has an N pole. Since both of the magnetic pole portions 6a and 7a have N poles, as described in FIG. 6A, the first output signal 10b and the second output signal 11b are offset by 0.3 V on the positive side. Therefore, the second reference signal 301 is set to + 0.3V. Thereby, energization switching of the applied voltage of the coil 5 is performed at the rotational position 90 degrees of the rotor 3 as desired.

  In addition, when the rotational position of the rotor 3 is from 90 degrees to 360 degrees, the conduction switching can be performed at a desired timing by repeating the same procedure as the above-mentioned 0 degrees to 90 degrees. This is because mechanical angles of 0 to 90 degrees, 90 to 180 degrees, 180 to 270 degrees, and 270 degrees to 360 degrees are equivalent as electrical angles.

  As described above, in the radial direction of the magnet 2, the magnetic flux detection portion 10a is located on the outer peripheral side than the central position of the magnetic pole portions 6a and 7a. Therefore, in the case of right rotation, the control circuit 13 changes the value of the second reference signal 301 to the + side when the polarity of both of the magnetic pole portions 6a and 7a is N pole, and the polarity of both of the magnetic pole portions 6a and 7a is In the case of the south pole, the value of the second reference signal 301 is changed to the minus side. The conventional output signals 10b and 11b in which the reference signal 301 is not changed are those shown in FIGS. 8 (a) and 8 (b). On the other hand, in the present embodiment, by changing the reference signal 301 as shown in FIG. 10, the output signals 10b and 11b are as shown in FIGS. 11 (a) and 11 (b). That is, the magnitude relationship of the second output signal 11b with the reference signal 301 is reversed at rotational positions of 45 degrees, 90 degrees, 135 degrees, and so on, and the applied voltage of the second coil 5 is switched at the desired timing. It is possible to do

  In the radial direction of the magnet 2, when the magnetic flux detection portion 10a is positioned on the inner peripheral side relative to the central position of the magnetic pole portions 6a and 7a, the magnetic flux detection portion 10a is positioned on the outer peripheral side. The change direction of the reference signal 301 is reversed. The relationship between the position of the magnetic flux detection unit of the third magnetic sensor 11 and the change direction of the first reference signal 300 can be considered in the same manner as in the case of the reference signal 301.

  The relationship between the rotational position of the rotor 3 when rotating the rotor 3 to the left, the polarity of the applied voltage of the coils 4 and 5, the magnetic poles of the magnetic pole portions 6a and 7a, and the setting values of the reference signals 300 and 301 is clockwise The opposite is the case. That is, in the case of left rotation, in the table of FIG. 10, each angle is set negative with respect to the rotational position of the rotor 3. Further, the magnetic pole of the magnetic pole portion 6a and the magnetic pole of the magnetic pole portion 7a are reversed, the polarity of the applied voltage of the coil 4 and the polarity of the applied voltage of the coil 5 are reversed, and the value of the first reference signal 300 and the second The value of the reference signal 301 is reversed.

  Thus, the control circuit 13 as the control means controls the direction of current supply to the first coil 4 based on the first comparison result signal 400, and the second coil based on the second comparison result signal 401. Control the direction of current supply to 5. At that time, the control circuit 13 as the changing means selects either the first reference signal 300 or the second reference signal 301 according to the rotation direction of the rotor 3, and selects the value of the selected reference signal The change is made according to the relationship between the polarity of the magnetic pole portion 6a and the polarity of the second magnetic pole portion 7a.

  The offset amounts of the first output signal 10b and the second output signal 11b are both 0.3 V, and the offset amounts of the reference signals 300 and 301 are also 0.3 V. However, depending on the positional relationship between the magnetic pole portion and the magnetic sensor, particularly in the radial direction, the direction and amount of offset of the output signals 10b and 11b may differ. In addition, the offset amount may be different between the first output signal 10b and the second output signal 11b. In these cases, the directions and the amounts of the offsets of the reference signals 300 and 301 may be set according to the directions and the amounts of the respective offsets, and the directions and the amounts of the two may not coincide with each other.

  According to the present embodiment, the control circuit 13 generates the comparison result signals 400 and 401 indicating the comparison results of the output signals 10b and 11b and the reference signals 300 and 301, which are output from the comparators 200 and 201, respectively. Control the direction of current flow to the coils 4 and 5. The control circuit 13 changes the values of the reference signals 300 and 301 according to the relationship between the polarity of the first magnetic pole 6a of the first yoke 6 and the polarity of the second magnetic pole 7a of the second yoke 7. . Thereby, the influence of the magnetic flux from the yokes 6 and 7 on the switching of the energization direction can be suppressed. Therefore, the energization switching timing to the intended coil can be realized.

  Hereinafter, modifications of the present embodiment will be described. Take right rotation as an example. In the example of FIG. 10, the control circuit 13 changes the value of the second output signal 11b in response to the inversion of the magnitude relationship between the second output signal 11b and the second reference signal 301, and The second reference signal 301 is switched to three types of -0.3V, 0V, and + 0.3V. However, each time the magnitude relationship between the second output signal 11 b and the second reference signal 301 is reversed, the value of the second reference signal 301 may be switched between positive and negative. That is, the value of the second reference signal 301 may be switched between −0.3 V and +0.3 V without passing through 0 V. In this case, the second reference signal 301 may be −0.3 V or +0.3 V described in the parentheses instead of 0 V in FIG. Then, in all rotational positions, the second reference signal 301 has a value of either -0.3 V or +0.3 V. As a result, the number of values to be taken can be reduced from three values of 0 V, -0.3 V and +0.3 V to two values of -0.3 V and 0.3 V, and the reference signal change for switching the values The configuration of the unit 500 (for example, a microcomputer) can be simplified.

  Although ± 0.3 V is exemplified as the change amount of the reference signal, the change amount is not limited to this value. For example, in general, the voltage applied to the coil may be changed to change the torque during motor drive. When the applied voltage is changed, the amount of magnetic flux due to the magnetic pole portions 6a and 7a changes, and the amount of offset of the output signals 10b and 11b changes. Therefore, the control circuit 13 may determine the amount of change of the values of the reference signals 300 and 301 according to the magnitude of the voltage applied to the first coil 4 and the second coil 5.

  In some cases, the offset amount of the output signal of the magnetic sensor can not be grasped in advance. Therefore, the control circuit 13 may determine the amount of change of the values of the reference signals 300 and 301 based on the output of each magnetic sensor when the rotor 3 is rotated with the reference signals 300 and 301 set to 0. This will be described with reference to FIG.

  FIG. 12 is a flowchart of reference signal setting processing for recording the offset amount of the output signal and setting the reference signal. This process is realized by the CPU of the control circuit 13 reading out a program stored in the ROM of the control circuit 13 to the RAM and executing the program. This process is started when an instruction for reference signal setting process is issued.

  First, the control circuit 13 starts driving of the motor 1, and records changes in the output signals 10b and 11b of the magnetic sensors 10 and 11 as recording information (step S101). Then, the control circuit 13 determines the change amount of the reference signal 300, 301 with respect to 0 based on the recorded recording information, thereby setting the value of the reference signal 300, 301 after the change (step S102). End the processing of 12.

Second Embodiment
The basic configuration of the second embodiment of the present invention is the same as that of the first embodiment, and is as described in FIG. However, the first reference signal 300 used in the comparator 200 (FIG. 9) and the second reference signal 301 used in the comparator 201 are both 0. The comparison result signals 400 and 401 become the Hi signal or the Low signal as shown in FIG. The comparison result signals 400 and 401 are respectively switched to the Hi signal and the Low signal at the positive / negative inversion timing of the output signals 10 b and 11 b. The control circuit 13 applies a first voltage to the first coil 4 and applies a second voltage to the second coil 5. The control circuit 13 applies a voltage of the same magnitude when the first coil 4 and the second coil 5 are energized.

  14 (a) and 14 (b) show the rotational position of the rotor 3 and the conduction polarity of the coil and the output signal in the case of rotating the rotor 3 clockwise (rotation in the clockwise direction in FIGS. 4 (a) and 4 (b)). And a comparison result signal. In FIGS. 14 (a) and 14 (b), as in FIG. 8, each relationship when the magnetic sensors 10 and 11 are disposed at the position corresponding to the electrical angle corresponding to the "desired rotational position of the rotor 3" It is done. Here, with respect to the first magnetic sensor 10, the desired rotational position of the rotor 3 is 22.5 degrees, 67.5 degrees, 112.5 degrees, 157.5 degrees, 202.5 degrees, 247 degrees in mechanical angle. It is 5 degrees, 292.5 degrees, 337.5 degrees .... Further, the desired rotational position of the rotor 3 is 0 degrees (360 degrees), 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees, 315 degrees, and so on for the third magnetic sensor 11. is there.

  As shown in FIGS. 14 (a) and 14 (b), when the polarity of the magnetic pole portion 6a is N pole and S pole, the comparison result signal 400 becomes a Hi signal and a Low signal, respectively. Similarly, when the polarity of the magnetic pole portion 7a is the N pole and the S pole, the comparison result signal 401 becomes the Hi signal and the Low signal, respectively. The comparison result signals 400 and 401 fall when the respective polarities of the magnetic pole portions 6a and 7a switch from the N pole to the S pole, and rise when the polarity changes from the S pole to the N pole.

  In this embodiment, waiting time has elapsed from the inversion timing of the output signals 10b and 11b, that is, the switching timing between the Hi signal and the Low signal of the comparison result signals 400 and 401, to each of the coils 4 and 5. Switch the power supply direction of. As described below, the waiting time is set in accordance with the relationship between the polarities of the magnetic poles of the magnetic pole portions 6a and 7a. Therefore, in the present embodiment, the magnetic sensors 10 and 11 are disposed at positions advanced (early) in phase by a predetermined electrical angle with respect to the electrical angle corresponding to the “desired rotational position of the rotor 3”. Specifically, the magnetic sensors 10 and 11 are disposed at a position where the lead phase is obtained by 10 degrees (40 degrees in electrical angle: predetermined electrical angle) in mechanical angle with respect to the desired rotational position of the rotor 3.

  FIGS. 15A and 15B show the relationship between the rotational position of the rotor 3 and the energization polarity of the coil and the output signal when the rotor 3 is rotated to the right when the magnetic sensors 10 and 11 are disposed in the lead phase. And a comparison result signal. As can be seen in comparison with FIG. 14, as a result of arranging the magnetic sensors 10 and 11 in the lead phase, waveforms 10r and 11r, output signals 10b and 11b, waveforms 10 (+) and 11 (+), and waveforms 10 (−) , 11 (−) are both shifted by 10 degrees (to the left in the figure).

  With such an arrangement, the inversion timing of the output signals 10b and 11b is advanced by 10 degrees in mechanical angle. Therefore, the rotor rotational position is 10 degrees at the switching timing between the Hi signal and the Low signal of the comparison result signals 400 and 401, as compared with the detection timing when the magnetic sensors 10 and 11 are not arranged in advance phase (FIG. 14). It is getting smaller. That is, regarding the magnetic sensor 10, the inversion timing of the output signal 10b is 22.5 degrees, 67.5 degrees, 112.5 degrees, 157.5 degrees, 202.5 degrees,. It was every degree. However, in the present embodiment (FIG. 15 (a)), the inversion timing is a value that is smaller by 10 degrees, and is 12.5 degrees, 57.5 degrees, 102.5 degrees, 147.5 degrees, 192.5 degrees,・ ・ ・ It has become every 45 degrees thereafter. Further, regarding the magnetic sensor 11, the inversion timing of the output signal 11b is 3.75 degrees, 48.75 degrees, 93.75 degrees, 138.75 degrees, 183.75 degrees, and so on in FIG. It was every degree. However, in the present embodiment (FIG. 15 (b)), the inversion timing is a value that is smaller by 10 degrees each, and is -6.25 degrees (= 353.75), 38.75 degrees, 83.75 degrees, 128.75. Degrees, 173.75 degrees, ... every 45 degrees thereafter.

  The control circuit 13 switches the conduction polarity (the conduction direction) of the first voltage applied to the coil 4 at the timing when the first waiting time Δt1 has elapsed from the inversion timing of the first output signal 10b. In addition, the control circuit 13 switches the conduction polarity (the conduction direction) of the second voltage applied to the coil 5 at the timing when the second waiting time Δt2 has elapsed from the inversion timing of the second output signal 11b. The first waiting time Δt1 and the second waiting time Δt2 are set as follows.

  First, at the time of the right rotation of the rotor 3, regarding the magnetic sensor 10, a delay in detection due to the influence of the polarity of the magnetic pole portion 6 a does not occur. Therefore, the control circuit 13 sets a time corresponding to 10 degrees in mechanical angle as the first waiting time Δt1. The first waiting time Δt1 is calculated according to the rotational speed (the number of rotations per unit time) of the rotor 3. Therefore, if the rotational speed changes, the first waiting time Δt1 is also changed. The control circuit 13 acquires the number of revolutions N (unit: rps) detected by the magnetic sensor 10. The control circuit 13 calculates the first waiting time Δt1 according to Δt1 (seconds) = 1 / N × (10 degrees / 360 degrees).

  On the other hand, at the time of the right rotation of the rotor 3, a delay of 3.75 degrees occurs in the detection of the magnetic sensor 11, so it is necessary to offset this. Therefore, the control circuit 13 sets 10 degrees −3.75 degrees = 6.25 degrees as the second waiting time Δt2. Therefore, the control circuit 13 calculates the second waiting time Δt2 according to Δt2 (seconds) = 1 / N × (6.25 degrees / 360 degrees). As a result, when the rotor 3 is rotated to the right, the second waiting time Δt2 is shorter than the first waiting time Δt1.

  By providing the waiting time, as shown in FIGS. 15 (a) and 15 (b), the desired switching timing of energization can be obtained. That is, by providing the first waiting time Δt1 when the rotor 3 rotates right, the energization switching timing of the first voltage applied to the coil 4 can be changed to the desired rotational position of the rotor 3 (22.5 degrees, 67 .. 5 degrees ... etc.). In addition, by providing the second waiting time Δt2 when the rotor 3 rotates right, the energization switching timing of the second voltage applied to the coil 5 can be set to the desired rotational position (0 degrees, 45 degrees・ ・ ・ Etc).

  In addition, depending on the rotation direction of the rotor 3, coils in which a delay in detection occurs due to the influence of the polarity of the magnetic pole portion are different. For example, at the time of the left rotation of the rotor 3, regarding the magnetic sensor 11, a delay in detection due to the influence of the polarity of the magnetic pole portion 7 a does not occur. Therefore, the control circuit 13 sets a time corresponding to 10 degrees in mechanical angle as the second waiting time Δt2. That is, the control circuit 13 calculates the second waiting time Δt2 according to Δt2 (seconds) = 1 / N × (10 degrees / 360 degrees).

  On the other hand, in the case of the magnetic sensor 10, a detection delay of 3.75 degrees occurs, which needs to be offset. Therefore, the control circuit 13 sets 10 degrees −3.75 degrees = 6.25 degrees as the first waiting time Δt1. Therefore, the control circuit 13 calculates the first waiting time Δt1 according to Δt1 (seconds) = 1 / N × (6.25 degrees / 360 degrees). As a result, when the rotor 3 is rotated to the right, the first waiting time Δt1 is shorter than the second waiting time Δt2.

  Thus, the control circuit 13 sets the waiting times Δt 1 and Δt 2 in accordance with the rotation direction of the rotor 3. As an example, the control circuit 13 interchanges the first waiting time Δt1 and the second waiting time Δt2 according to the rotation direction of the rotor 3. The rotational direction of the rotor 3 can be grasped from the relationship (the manner of change) between the polarity of the magnetic pole portion 6a and the polarity of the magnetic pole portion 7a. As a result, it is possible to realize the switching timing of energization to the intended coil in the rotational direction (drive direction) in both directions.

  The relationship between the lengths of one of the waiting times Δt 1 and Δt 2 and the other is as follows. The other one of the waiting times Δt1 and Δt2 is a delay of the inversion timing of the output signal which is generated when it is assumed that the corresponding magnetic sensor is arranged at the position corresponding to the electrical angle corresponding to the desired rotational position of the rotor 3. The time corresponding to the, one shorter than one. However, it is not essential that the amount of the waiting time Δt1 or Δt2 shorter than one of the other is equal to the time corresponding to the delay of the inversion timing of the output signal.

  According to the present embodiment, the control circuit 13 switches the energization direction of the coils 4 and 5 at the timing when the waiting time has elapsed from the inversion timing of the output signals of the magnetic sensors 10 and 11. The control circuit 13 sets the waiting time according to the relationship between the polarity of the magnetic pole 6a and the polarity of the magnetic pole 7a. As a result, the same effect as that of the first embodiment can be obtained in suppressing the influence of the magnetic flux from the yokes 6 and 7 on the switching of the energization direction.

  Next, a modification of the second embodiment will be described. First, the position of the magnetic sensors 10 and 11 is disposed at a position leading by 10 degrees in mechanical angle with respect to the desired rotational position of the rotor 3, but the value of 10 degrees is an example, and is limited to this value I will not. For example, it is assumed that θ2 degrees is adopted instead of 10 degrees. In this case, at the time of right rotation of the rotor 3, the control circuit 13 calculates the first waiting time Δt1 by Δt1 (seconds) = 1 / N × (θ2 degrees / 360 degrees). Further, the control circuit 13 calculates a second waiting time Δt2 by Δt2 (seconds) = 1 / N × (θ2−3.75 degrees / 360 degrees). When the rotor 3 rotates left, the first waiting time Δt1 and the second waiting time Δt2 may be interchanged.

  In addition, although 3.75 degrees are illustrated as an angle of detection delay by the magnetic sensor 11 at the time of right rotation of the rotor 3, when the angle of detection delay is Δα, it may be performed as follows. The control circuit 13 calculates the first waiting time Δt1 according to Δt1 (seconds) = 1 / N × (θ2 degrees / 360 degrees). Further, the control circuit 13 calculates the second waiting time Δt2 by Δt2 (seconds) = 1 / N × (θ2−Δα degree / 360 degrees). Here, if θ2 degrees and Δα degrees are made to coincide with each other, Δt2 (seconds) = 0. When the rotor 3 rotates left, the first waiting time Δt1 and the second waiting time Δt2 may be interchanged. Therefore, it is also possible to make one of the waiting times zero.

  The offset amounts of the output signals 10 b and 11 b are both 0.3 V. However, the offset amount may be different between the first output signal 10 b and the second output signal 11 b. In these cases, the control circuit 13 may set the first waiting time Δt1 and the second waiting time Δt2 in accordance with the direction and amount of each offset. Furthermore, the voltage applied to the coil may be changed to change the torque during motor drive. When the applied voltage is changed, the offset amount of the output signals 10b and 11b changes. Therefore, the control circuit 13 may set the waiting times Δt 1 and Δt 2 in accordance with the magnitudes of the voltages applied to the first coil 4 and the second coil 5.

  Further, there are cases where the offset amount of the output signals 10 b and 11 b can not be grasped in advance due to individual differences of motors, changes in temperature environment, and the like. In that case, as described with reference to FIG. 16, the control circuit 13 may set the waiting times Δt1 and Δt2 based on the motor output information recorded in association with the time.

  FIG. 16 is a flowchart of the waiting time setting process. This process is realized by the CPU of the control circuit 13 reading out a program stored in the ROM of the control circuit 13 to the RAM and executing the program. This process is started when an instruction for waiting time setting process is issued.

  First, in step S1601, the control circuit 13 operates the motor 1 in various waiting times with the waiting time as a variable, and measures motor output information (at least one of rotational speed and generated torque). In step S1602, the control circuit 13 records motor output information in association with the waiting time. In step S1603, control circuit 13 refers to the recorded motor output information, and sets waiting times corresponding to conditions (rotational speed or generated torque) at the time of actually driving motor 1 as waiting times Δt1 and Δt2. . Thereafter, the control circuit 13 ends the process of FIG.

  Note that the control circuit 13 may approximate the correspondence between the waiting time and the motor output information by using a mathematical expression, and may calculate the waiting times Δt1 and Δt2 using this approximate expression. Alternatively, instead of the motor output, the waveform of the magnetic flux detected by the magnetic sensors 10 and 11 may be measured, the detection delay may be calculated, and the detection delay may be reflected in the setting of the waiting times Δt1 and Δt2. What is used for the measurement of the waveform of the detected magnetic flux may be one that can detect the magnetic flux, and may be a Hall element or another magnetic sensor. When obtaining detection delay information, the delay of the detection timing of the magnetic sensor may be calculated by comparing the position information by the highly accurate position detection sensor provided separately and the detection result of the magnetic sensor.

  In the present embodiment, provision of the comparators 200 and 201, the second magnetic sensor 8 and the fourth magnetic sensor 9 is not essential.

  The output signals 10 b and 11 b change depending on the rotational position of the rotor 3 and the voltage applied to the coils 4 and 5. Therefore, in the first embodiment, the control circuit 13 may set the reference signals 300 and 301 from the information in which they are recorded. In the second embodiment, the control circuit 13 may reflect the recorded information in the settings of the waiting times Δt1 and Δt2. These can cope with the case where the offset amount of the output signal of the magnetic sensor can not be grasped in advance. Also, the magnet and coil have characteristic changes due to temperature. Therefore, in the first embodiment, the control circuit 13 may also record information on the temperature of the motor 1 or the temperature near the motor 1 as recording information, and set the reference signals 300 and 301 in consideration of it. . In the second embodiment, the control circuit 13 may reflect the recording information in the setting of the waiting times Δt 1 and Δt 2. By these, even if there is an influence by temperature, the timing of energization switching to the intended coil can be realized, which is more preferable.

  In each of the above embodiments, attention was paid to the influence of the magnetic flux of the magnetic pole portions 6a and 7a, but in addition to this, when there is an object that generates magnetism near the motor 1, the output signal of the magnetic sensor affects Receive For example, when another motor or solenoid, such as a motor or a solenoid, is provided in the vicinity of the motor 1, the output signal of the magnetic sensor changes. Therefore, in the first embodiment, the control circuit 13 determines the amount of change of the values of the reference signals 300 and 301 based on the information of the magnetic flux generated from the object arranged adjacent to the rotor 3. It is also good. In that case, information on the magnetic flux may be obtained in advance by measurement or the like. In the second embodiment, the control circuit 13 may set the waiting times Δt1 and Δt2 based on the information of the magnetic flux generated from the object.

  In each of the above embodiments, although the configuration of two magnetic sensors and two comparators has been described, it is assumed that there is one magnetic sensor and one comparator, and the comparison result between the comparator and the reference signal is two. The present invention can also be applied to a configuration in which the direction of energization of two coils is switched.

  Although the present invention has been described in detail based on its preferred embodiments, the present invention is not limited to these specific embodiments, and various embodiments within the scope of the present invention are also included in the present invention. included. Some of the embodiments described above may be combined as appropriate.

Reference Signs List 2 magnet 3 rotor 4, 5 coil 6, 7 yoke 6a, 7a magnetic pole portion 10, 11 magnetic sensor 13 control circuit 200, 201 comparator

Claims (22)

A rotatable rotor formed in a cylindrical shape and provided with a magnet which is divided into a plurality of pieces in the circumferential direction and alternately magnetized with different poles at different poles;
A first yoke provided with a first magnetic pole opposed to the outer peripheral surface of the rotor;
A second yoke provided with a second magnetic pole that faces the outer peripheral surface of the rotor and is disposed at a position where the electrical angle is shifted with respect to the first magnetic pole portion;
A first coil which excites the first magnetic pole portion by being energized;
A second coil which excites the second magnetic pole portion by being energized;
A motor control device for controlling a motor including: a magnetic sensor disposed to face the outer peripheral surface of the rotor and outputting a signal according to a magnetic flux;
A comparator that outputs a comparison result signal indicating a comparison result of the output signal of the magnetic sensor and a reference signal;
Control means for controlling the direction of energization of the first coil and the second coil based on the comparison result signal output by the comparator;
A motor control device comprising: changing means for changing the value of the reference signal in accordance with the relationship between the polarity of the first magnetic pole portion and the polarity of the second magnetic pole portion.   When the polarity of the first magnetic pole portion and the polarity of the second magnetic pole portion are both N pole, the changing means may have the polarity of the first magnetic pole portion and the polarity of the second magnetic pole portion. 2. The motor control device according to claim 1, wherein the positive and negative values of the reference signal are reversed in both cases of the S pole. The magnetic sensor is disposed radially outward of the magnet with respect to the first magnetic pole portion and the second magnetic pole portion.
When the polarity of the first magnetic pole portion and the polarity of the second magnetic pole portion are both N pole, the changing means changes the value of the reference signal to the positive side, and 3. The motor control device according to claim 2, wherein when the polarity and the polarity of the second magnetic pole portion are both S poles, the value of the reference signal is changed to the-side.   The said change means changes the value of the said reference signal according to the magnitude correlation of the said comparison result signal and the said reference signal having been inverted, The any one of the Claims 1-3 characterized by the above-mentioned. Motor controller.   5. The motor control device according to claim 4, wherein the changing unit switches positive and negative values of the reference signal each time the magnitude relation between the comparison result signal and the reference signal is inverted.   The said change means determines the change amount of the value of the said reference signal according to the magnitude | size of the voltage applied to a said 1st coil and a said 2nd coil, The any one of the Claims 1-5 characterized by the above-mentioned. The motor control device according to any one of the preceding claims.   6. The apparatus according to claim 1, wherein said changing means determines the amount of change of the value of said reference signal based on the output of said magnetic sensor when said rotor is rotated with said reference signal being 0. The motor control device according to any one of the items.   The said change means determines the change amount of the value of the said reference signal based on the information of the magnetic flux generate | occur | produced from the object arrange | positioned adjacent to the said rotor, The any one of the Claims 1-5 characterized by the above-mentioned. The motor control apparatus as described in a term. The magnetic sensor includes a first magnetic sensor and a second magnetic sensor.
A first comparator that compares a first output signal of the first magnetic sensor with a first reference signal and outputs a first comparison result signal; and A second comparator that compares a second output signal of the sensor with a second reference signal and outputs a second comparison result signal;
The control means controls the direction of current supply to the first coil based on the first comparison result signal, and controls the direction of current supply to the second coil based on the second comparison result signal. ,
The changing means selects either the first reference signal or the second reference signal according to the rotation direction of the rotor, and selects the value of the selected reference signal as the polarity of the first magnetic pole portion The motor control device according to any one of claims 1 to 8, wherein the motor control device is changed according to the relationship with the polarity of the second magnetic pole part. A rotatable rotor formed in a cylindrical shape and provided with a magnet which is divided into a plurality of pieces in the circumferential direction and alternately magnetized with different poles at different poles;
A first yoke provided with a first magnetic pole opposed to the outer peripheral surface of the rotor;
A second yoke provided with a second magnetic pole that faces the outer peripheral surface of the rotor and is disposed at a position where the electrical angle is shifted with respect to the first magnetic pole portion;
A first coil which excites the first magnetic pole portion by being energized;
A second coil which excites the second magnetic pole portion by being energized;
A motor control device for controlling a motor including: a magnetic sensor disposed to face the outer peripheral surface of the rotor and outputting a signal according to a magnetic flux;
Control means for switching the direction of energization of the first coil or the second coil at a timing when a waiting time has elapsed from the inversion timing of the output signal of the magnetic sensor;
And a setting unit configured to set the waiting time according to the relationship between the polarity of the first magnetic pole portion and the polarity of the second magnetic pole portion.   The motor control device according to claim 10, wherein the setting means sets the waiting time in accordance with a rotation direction of the rotor. The magnetic sensor includes a first magnetic sensor and a second magnetic sensor.
The control means switches the energization direction of the first coil at a timing when a first waiting time has elapsed from the reversal timing of the first output signal of the first magnetic sensor, and the second control method of the second magnetic sensor Switching the current supply direction of the second coil at a timing when a second waiting time has elapsed from the inversion timing of the second output signal,
12. The motor control device according to claim 10, wherein the setting means interchanges the first waiting time and the second waiting time according to the rotation direction of the rotor. Both the first magnetic sensor and the second magnetic sensor are disposed at positions advanced in phase by a predetermined electrical angle with respect to the electrical angle corresponding to the desired rotational position of the rotor.
One of the first waiting time and the second waiting time is a time corresponding to the predetermined electrical angle, and one of the first waiting time and the second waiting time is the other. The motor control device according to claim 12, characterized in that the time is shorter than any one of them.   The other one corresponds to the delay of the inversion timing of the output signal which occurs when it is assumed that the corresponding magnetic sensor is disposed at the position corresponding to the electrical angle corresponding to the desired rotational position of the rotor. The motor control device according to claim 13, characterized in that the time is shorter than any one of the time.   The said setting means sets the said waiting time according to the magnitude | size of the voltage applied to a said 1st coil and a said 2nd coil, The said setting means is described in any one of the Claims 10-14 characterized by the above-mentioned. Motor controller.   The motor control device according to any one of claims 10 to 14, wherein the setting means sets the waiting time in accordance with a rotational speed of the rotor.   The motor according to any one of claims 10 to 14, wherein the setting means sets the waiting time based on information of magnetic flux generated from an object arranged adjacent to the rotor. Control device.   The said setting means sets the said waiting time based on the information which matched at least one of the rotational speed or the torque of the said rotor, and time, The any one of the Claims 10-14 characterized by the above-mentioned. Motor controller.   The motor according to any one of claims 10 to 18, wherein the magnetic sensor is disposed on the outer peripheral side in the radial direction of the magnet than the first magnetic pole part and the second magnetic pole part. Control device. A rotatable rotor formed in a cylindrical shape and provided with a magnet which is divided into a plurality of pieces in the circumferential direction and alternately magnetized with different poles at different poles;
A first yoke provided with a first magnetic pole opposed to the outer peripheral surface of the rotor;
A second yoke provided with a second magnetic pole that faces the outer peripheral surface of the rotor and is disposed at a position where the electrical angle is shifted with respect to the first magnetic pole portion;
A first coil which excites the first magnetic pole portion by being energized;
A second coil which excites the second magnetic pole portion by being energized;
A motor control method for controlling a motor, comprising: a magnetic sensor disposed to face the outer peripheral surface of the rotor and outputting a signal according to a magnetic flux.
Outputting a comparison result signal indicating the comparison result of the output signal of the magnetic sensor and the reference signal;
A control step of controlling an energization direction of the first coil and the second coil based on the comparison result signal output in the comparison step;
And V. changing the value of the reference signal in accordance with the relationship between the polarity of the first magnetic pole portion and the polarity of the second magnetic pole portion. The magnetic sensor includes a first magnetic sensor and a second magnetic sensor.
The comparing step compares a first output signal of the first magnetic sensor with a first reference signal to output a first comparison result signal, and a second output of the second magnetic sensor. Comparing the signal with a second reference signal and outputting a second comparison result signal,
The control step controls an energization direction of the first coil based on the first comparison result signal, and controls an energization direction of the second coil based on the second comparison result signal. ,
The changing step selects either the first reference signal or the second reference signal according to the rotation direction of the rotor, and selects the value of the selected reference signal as the polarity of the first magnetic pole portion 21. The motor control method according to claim 20, wherein the motor control method is changed according to the relationship with the polarity of the second magnetic pole part. A rotatable rotor formed in a cylindrical shape and provided with a magnet which is divided into a plurality of pieces in the circumferential direction and alternately magnetized with different poles at different poles;
A first yoke provided with a first magnetic pole opposed to the outer peripheral surface of the rotor;
A second yoke provided with a second magnetic pole that faces the outer peripheral surface of the rotor and is disposed at a position where the electrical angle is shifted with respect to the first magnetic pole portion;
A first coil which excites the first magnetic pole portion by being energized;
A second coil which excites the second magnetic pole portion by being energized;
A motor control method for controlling a motor, comprising: a magnetic sensor disposed to face the outer peripheral surface of the rotor and outputting a signal according to a magnetic flux.
A control step of switching an energization direction of the first coil or the second coil at a timing when a waiting time has elapsed from an inversion timing of an output signal of the magnetic sensor;
A setting step of setting the waiting time according to the relationship between the polarity of the first magnetic pole portion and the polarity of the second magnetic pole portion.

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