JP2008295205A - Apparatus and method for motor drive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor driving device that can generate an advance signal through a simple circuit without imposing a large load, achieves size and cost reduction, and enables high-speed rotation of a motor. <P>SOLUTION: An advance synthesis unit 13 includes inverting amplifiers 21 to 24, adder circuits 25, 26, and binary circuits 27, 28 and amplifies signals obtained from a first sensor 6a by a factor of A. The amplified signals are inverted and added according to mathematical expression (5): first advance signal=A×R/R1×sinθ+A×R/R2×cosθ and mathematical expression (6): second advance signal=A×R/R1×cosθ-A×R/R2×sinθ. A signal advanced by an arbitrary lead angle α is generated by selecting such values that R/R1=cosα and R/R2=sinα for variable resistors R1, R2. The lead angle α is varied by varying the values of the variable resistors according to the rotation speed of a rotor. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a motor driving device and a motor driving method for rotating a rotor by sequentially switching a current supplied to a first coil and a second coil with respect to a motor.

  Conventionally, stepping motors have features such as small size, high torque, and long life. A digital positioning operation can be easily realized by driving the stepping motor by open loop control. For this reason, stepping motors are widely used in information appliances such as cameras and optical disk devices, and office automation equipment such as printers and projectors.

  However, there is a problem that the motor will step out when the load on the motor is large or when high-speed rotation is attempted. In order to solve this problem, a method of preventing step-out by attaching an encoder to a stepping motor and switching the energization in accordance with the position of the rotor, so that the stepping motor performs a so-called brushless DC motor operation has been conventionally performed. It was.

  Patent Documents 1, 2, and 3 disclose brushless motors that enable high-speed rotation by the above method. These motors cover a delay in the rise of current by exciting a coil with a position signal obtained by advancing a signal obtained from a non-contact type position sensor in accordance with a speed. This technique will be described with reference to FIGS.

  First, the principle of the brushless motor is shown. FIG. 9 is a diagram showing a conventional two-phase coil A, B and rotor 101. FIG. 10 is a graph showing the torque distribution when a constant current is passed through each phase. The horizontal axis indicates the electrical angle θ, and the vertical axis indicates the torque. Since currents in the forward and reverse directions can flow through the two coils A and B, four types of torque distributions are obtained. By switching energization in accordance with the rotational position of the rotor 101, a torque curve T is obtained for the brushless motor.

  FIG. 11 is a graph showing temporal changes in excitation voltage and excitation current. Since the excitation current h is affected by the inductance of the coil, the excitation current h rises with a delay from the excitation voltage i. For this reason, as the rotation of the rotor increases, the angle at which the excitation to the coil is switched is advanced so that the coil is energized earlier than the timing shown in FIG. As a result, the delay in the rise of the excitation current can be covered, and the torque can be stabilized even during high-speed rotation. FIG. 12 is a graph showing the relationship between torque and advance angle. In this graph, torque according to the number of revolutions is shown for advancing angle a, advancing angle b, and advancing angle c. The advance angle at which the maximum torque can be obtained varies depending on the rotational speed of the rotor. That is, in the drawing, the maximum torque is obtained at the large advance angle c up to the rotational speed d, but the maximum torque is obtained at the intermediate speed b after the rotational speed d. Thus, by selecting the optimum advance angle according to the rotational speed, it is possible to provide a highly efficient motor even during high-speed rotation.

In Patent Documents 1 and 2 described above, the time for the rotor to move one step is measured by a timer, and the advance angle is adjusted by calculating based on the time. In Patent Document 3 described above, in order to realize the same technical idea, there is a method of giving a lead angle by using a high-resolution encoder and changing the number of counts at the time of frequency division when a certain speed is exceeded. It is disclosed.
Japanese Patent Publication No. 06-0667259 JP 2002-359997 A JP-A-10-150798

  However, the conventional motor driving device has the following problems. That is, the means described in Patent Documents 1 and 2 have a problem in that it is necessary to constantly monitor the speed in order to obtain an advance angle, and the circuit load increases. In particular, since a procedure for fetching a timer value for each step and calculating an advance angle is required, the higher the speed, the higher the frequency of calculation and the greater the circuit load. In addition, since the advance angle is calculated using the time interval one step before, there is also a problem that the advance angle changes depending on a rapid speed change that occurs during one step.

  Further, in the method disclosed in Patent Document 3, in order to obtain an advance angle, the angle is directly measured by an encoder instead of measuring time. For this reason, the burden on the control side is extremely small. Further, the advance angle can be determined without depending on the speed. However, since a high-resolution encoder is required, there is a problem that it is difficult to reduce the size and cost of the motor.

  Therefore, the present invention can create an advance angle signal with a simple circuit without applying a large load, achieve a reduction in size and cost, and enable a motor to rotate at high speed, and a motor driving method The purpose is to provide.

  In order to achieve the above object, a motor drive device of the present invention includes a rotor having a magnet, a first coil, a second coil, and first and second position detecting means for detecting the position of the magnet. And a motor driving device that rotates the rotor by sequentially switching currents supplied to the first coil and the second coil with respect to a motor configured by a stator that rotatably supports the rotor. Then, the signal obtained by multiplying the signal obtained from the first position detecting means by the first coefficient a1 and the signal obtained by multiplying the signal obtained from the second position detecting means by the second coefficient a2 are added. And a signal obtained by multiplying the signal obtained from the first position detection means by the third coefficient b1 and the signal obtained from the second position detection means. An advance angle synthesizing means for adding a signal multiplied by a coefficient b2 of 4 to generate a second advance angle signal; and switching the energization to the first coil by the first advance angle signal; And a control means for switching energization to the second coil according to an advance angle signal.

  The motor drive device of the present invention includes a rotor having a magnet, a first coil, a second coil, and a stator that rotatably detects the position of the magnet, and includes a stator that rotatably supports the rotor. A motor driving device for rotating the rotor by sequentially switching the currents supplied to the first coil and the second coil with respect to the motor to be driven, the voltage of the signal obtained from the position detection means and the first Comparing means for comparing the threshold value with a first threshold value and comparing the voltage with a second threshold value higher than the first threshold value; and when the voltage exceeds the first threshold value and when the threshold value is equal to the second threshold value. And control means for switching energization to the first coil and the second coil when the value falls below the threshold value.

  The motor driving method of the present invention includes a rotor having a magnet, a first coil, a second coil, and first and second position detecting means for detecting the position of the magnet, and the rotor is rotatable. A motor driving method for rotating the rotor by sequentially switching a current supplied to the first coil and the second coil with respect to a motor constituted by a supporting stator, wherein the first position detection A signal obtained by multiplying the signal obtained from the means by the first coefficient a1 and a signal obtained by multiplying the signal obtained from the second position detecting means by the second coefficient a2 are added to obtain a first advance signal. A signal obtained by multiplying the signal obtained from the first position detection means by the third coefficient b1, and a signal obtained by multiplying the signal obtained from the second position detection means by the fourth coefficient b2. And an advance angle synthesizing step for generating a second advance angle signal, switching the energization to the first coil by the first advance angle signal, and the second advance angle signal to switch the second And a control step for switching energization of the coil.

  A motor driving method according to the present invention includes a rotor having a magnet, a first coil, a second coil, and a stator that includes a position detection unit that detects the position of the magnet and rotatably supports the rotor. A motor driving method for rotating the rotor by sequentially switching the current supplied to the first coil and the second coil with respect to the motor to be driven, the voltage of the signal obtained from the position detection means and the first A comparison step of comparing the threshold value with a first threshold value and comparing the voltage with a second threshold value that is higher than the first threshold value; and when the voltage exceeds the first threshold value; And a control step of switching energization to the first coil and the second coil when the value falls below the threshold value.

  According to the motor drive device of the first aspect of the present invention, the advance angle signal can be generated with a simple circuit without applying a large load, and the motor can be reduced in size and cost, and the motor can be rotated at high speed. It is. Therefore, it is not necessary to use an expensive encoder that hinders realization of downsizing as in the prior art. According to the motor drive device of the second aspect, it can be realized with a relatively simple circuit. According to the motor drive device of the third aspect, the optimum advance angle can be given according to the rotation speed, and the efficiency of the motor can be increased.

  According to the motor driving device of the fourth aspect of the present invention, it is possible to generate an advance angle signal with a simple circuit without applying a large load, to realize a reduction in size and cost, and to enable high-speed rotation of the motor. It is. Further, only one position detecting means can be used. Furthermore, since switching of energization is determined by the angle of the rotor without depending on the rotation direction of the motor, it can be realized by the same circuit regardless of the rotation direction of the motor. According to the motor driving device of the fifth aspect, a signal having an advance angle of α degrees can be generated. According to the motor drive device of the sixth aspect, the optimum advance angle can be given according to the rotation speed, and the efficiency of the motor can be increased. According to the motor drive device of the seventh aspect, detection can be performed using the magnet and the Hall element, and a new member for knowing the position of the rotor is not prepared, leading to miniaturization of the motor.

  Embodiments of a motor driving device and a motor driving method of the present invention will be described with reference to the drawings. The motor drive device of this embodiment is applied to a stepping motor control device.

[First Embodiment]
FIG. 1 is a perspective view showing the configuration of the stepping motor in the first embodiment. For ease of explanation, some parts are shown as broken. The stepping motor 1 includes a rotor 3 having a magnet 2, a first coil 4a, a second coil 4b, a first yoke 5a, a second yoke 5b, a first sensor 6a, and a second sensor 6b. The Among these, the first coil 4a, the second coil 4b, the first yoke 5a and the second yoke 5b, the first sensor 6a and the second sensor 6b constitute a stator.

  The magnet 2 is a cylindrical permanent magnet whose outer periphery is magnetized with multiple poles. The magnet 2 has a magnetization pattern in which the strength of the magnetic force in the radial direction changes in a sine wave shape according to the angular position. The rotor 3 is integrally supported by the magnet 2 and is supported rotatably with respect to the stator.

  The first yoke 5a has a plurality of magnetic pole teeth excited by the first coil 4a. The torque applied to the rotor 3 can be changed by switching the poles to be excited. The first sensor 6 a and the second sensor 6 b are Hall elements, detect the magnetic flux (magnetism) of the magnet 2, and output signals that are 90 degrees out of phase with each other in electrical angle. Here, if the number of poles of the magnet 2 is n, the electrical angle of 360 ° corresponds to the actual rotor angle of 720 / n °. The first sensor 6a and the second sensor 6b correspond to a first position detection unit and a second position detection unit according to claim 1, respectively.

  FIG. 2 is a diagram showing a configuration of a motor drive circuit for driving the stepping motor. The motor drive circuit 10 includes a current driver 11, a controller 12, and an advance angle synthesis unit 13. The current driver 11 is a current drive circuit that corresponds to an input signal and causes a current in a predetermined direction to flow through the first coil 4a and the second coil 4b.

  The controller 12 determines a current to be supplied to the current driver 11 in accordance with a rotation direction signal and a drive pulse signal input from the outside. The current passed through the first coil 4a is switched at the timing of the first advance signal, and the current passed through the second coil 4b is switched at the timing of the second advance signal. Further, the controller 12 counts the first sensor signal and the second sensor signal, and when the predetermined pulse is reached, the controller 12 is turned off.

  Note that the present invention relates to a method of synthesizing the advance angle when the motor is driven, and the specific operation method of the controller is not limited. As the operation method of the controller, a known technique can be used according to the method of using the motor or the control method. For example, there is a method of switching to open-loop control such as microstep driving, in which the current passed through the coil is changed after reaching a predetermined speed or position.

  The advance angle synthesizing unit 13 is a circuit that synthesizes the first and second advance angle signals from the sensor signals obtained from the first sensor 6a and the second sensor 6b and the instructed rotation direction signal. The synthesized advance angle signal is input to the current driver 11 via the controller 12 and used as a signal for instructing the timing for switching the energization of the coil.

  Here, the advance angle synthesis method in the advance angle synthesis unit 13 will be described in detail. FIG. 3 is a graph showing waveforms of the first and second sensor signals and the advance angle signal output from the first sensor 6a and the second sensor 6b, respectively. In the figure, the vertical axis represents the signal magnitude, and the horizontal axis represents the electrical angle θ. As described above, since the strength of the magnetic force in the radial direction of the magnet 2 is magnetized so as to be approximately sinusoidal with respect to the electrical angle, a substantially sinusoidal signal can be obtained from the first sensor 6a. . Further, since the second sensor 6b is arranged with a phase difference of 90 ° in electrical angle with respect to the first sensor 6a, a cosine wave signal is obtained from the second sensor 6b. From these two signals, a signal having an arbitrary advance angle can be generated.

  First, when it is desired to create an advance angle signal advanced by α ° with respect to the first sensor 6a, the signal obtained by Equation (1) is set as the first advance angle signal. FIG. 3 shows a case where an advance angle of 30 degrees is given.

First sensor signal [sin θ] × cos α + second sensor signal [cos θ] × sin α (1)
Further, the signal obtained by Expression (2) is set as a second advance angle signal.

Second sensor signal [cos θ] × cos α−first sensor signal [sin θ] × sin α (2)
As a result, the first advance signal becomes sin (θ + α), and the second advance signal becomes cos (θ + α), which has an advance angle of α ° with respect to the first sensor signal and the second sensor signal, respectively. It becomes possible to give. Then, by binarizing the first and second advance signals, a desired timing for switching the coil energization can be created.

  Further, when the motor is rotated in the reverse direction, a negative advance angle is required to switch the energization earlier than the timing of FIG. In this case, the signal obtained by Expression (3) is set as the first advance angle signal.

First sensor signal [sin θ] × cos α−second sensor signal [cos θ] × sin α (3)
Further, the signal obtained by Expression (4) is set as the second advance angle signal.

Second sensor signal [cos θ] × cos α + first sensor signal [sin θ] × sin α (4)
As a result, the first advance signal becomes sin (θ-α), and the second advance signal becomes cos (θ-α), which is -α with respect to the first sensor signal and the second sensor signal, respectively. It is possible to give an advance angle of °.

  FIG. 4 is a circuit diagram showing a configuration of the advance angle synthesis unit 13. The advance angle synthesizing unit 13 includes inverting amplifiers 21, 22, 23, 24, addition circuits 25, 26, and binarization circuits 27, 28. First, the signal obtained from the first sensor 6a is amplified by an amplification factor A. Also, an inverted version of the amplified signal is prepared. By adding these signals, the signals shown in equations (5) and (6) are obtained.

First advance signal = A.R / R1.sin.theta. + A.R / R2.cos .theta. (5)
Second advance signal = A · R / R1 · cos θ−A · R / R2 · sin θ (6)
Therefore, by selecting values such that R / R1 = cos α and R / R2 = sin α for the variable resistors R1 and R2, it is possible to create (generate) a signal advanced by an arbitrary advance angle α. Here, A · R / R1 (= A · cos α) is multiplied by the signal obtained from the first sensor 6a and the first coefficient a1 and the second sensor 6b according to claim 1. This corresponds to the fourth coefficient b2 multiplied by the obtained signal. A · R / R2 (= A · sin α) corresponds to the second coefficient a2 multiplied by the signal obtained from the second sensor 6b. A · R / R2 (= −A · sin α) corresponds to the third coefficient b1 multiplied by the signal obtained from the first sensor 6a.

  Further, by changing the value of the variable resistance in accordance with the rotation speed of the rotor and changing the advance angle α, the advance angle at each speed can be optimized and the motor efficiency can be increased. At this time, the speed can be obtained by a known method such as differentiation of the sensor signal.

  FIG. 5 is a circuit diagram showing a configuration of the advance angle synthesizing unit 13 when the rotation direction of the motor is reversed. The advance angle synthesizing unit 13 includes inverting amplifiers 31, 32, 33, 34, addition circuits 35, 36, and binarization circuits 37, 38. When the rotation direction of the motor is reversed, the first advance angle signal and the second advance angle signal can be obtained by Expressions (7) and (8).

First advance signal = A · R / R1 · sin θ−A · R / R2 · cos θ (7)
Second advance angle signal = A · R / R1 · cos θ + A · R / R2 · sin θ (8)
Therefore, by selecting values for the variable resistors R1 and R2 such that R / R1 = cos α and R / R2 = sin α, it is possible to generate a signal delayed by an arbitrary advance angle α. Depending on the motor characteristics and usage conditions, different advance angles may be required for forward rotation and reverse rotation. In such a case, by adjusting the values of the variable resistors R1 and R2, another advance angle can be given according to the rotation direction. 4 and 5 may be selectively switched according to the rotation direction of the motor, or only one of the circuits is mounted when the rotation direction of the motor is determined. May be.

  The effect of the motor drive device of the first embodiment will be described. In the advance angle adjusting method of the present embodiment, the angle of the rotor can be directly measured by a sensor. Therefore, as shown in Patent Documents 1 and 2, the load applied to the circuit is much smaller than the method of calculating the speed measured at each step and creating the advance by creating the time delay.

  Further, in the conventional method of calculating the advance angle from the time interval one step before, it is impossible to accurately obtain the advance angle when a sudden speed change occurs during one step. In the worst case, the motor may stop rotating. On the other hand, in the present embodiment, since the advance angle is obtained directly by the sensor, an abnormal operation does not occur even with a rapid speed change, and a stable operation can be performed.

  In this embodiment, a high-resolution encoder is not necessary. Therefore, an increase in motor cost can be avoided. Further, in this embodiment, the magnet of the rotor can be used for position detection. Thereby, it is possible to reduce the size of the motor without preparing a new member for knowing the position of the rotor.

  Further, as shown in Patent Document 3, when an incremental type high resolution encoder is used, position information is lost when the power is turned off. For this reason, when the power is turned on or during abnormal operation, an operation for obtaining the initial position is required, such as abutting against a stopper to determine the position of the encoder. On the other hand, in this embodiment, since the position of the rotor is obtained directly from the analog signals of the two sensors, an operation for obtaining the initial position is not necessary.

  In general, the Hall element has temperature dependency, but in this embodiment, the sensor characteristic change due to the temperature change can be compensated. This will be described below.

  It is assumed that the sensitivity of the Hall element has increased by a factor of X by changing the temperature of the environment in which the Hall element is used. At this time, since the same Hall element is used as the two position sensors, the rate of change in sensitivity is substantially equal. Accordingly, the advance angle signal generated from the two sensor signals is expressed by equations (9) and (10).

First advance angle signal = X · A sin θ · cos α + X · A cos θ · sin α = X · A · sin (θ + α) (9)
Second advance signal = X · A cos θ · cos α−X · A sin θ · sin α = X · A · cos (θ + α) (10)
That is, even if the sensitivity changes, the advance signal intensity is only multiplied by X, and there is no change in the angular direction. Since this signal is binarized and used, even if the strength of the signal is multiplied by X due to a temperature change, the operation of the motor is not affected. In other words, the Hall element characteristic change due to temperature change does not affect the energization switching position of the coil.

[Second Embodiment]
FIG. 6 is a diagram showing a configuration of the advance angle synthesis unit in the second embodiment. By replacing the advance angle synthesizing unit 33 of the second embodiment with the advance angle synthesizing unit 13 of the first embodiment, a stepping motor control device for driving the stepping motor 1 of FIG. 1 is configured. However, in the second embodiment, the advance angle synthesizing unit 33 inputs only one sensor signal from one sensor (the first sensor 6a or the second sensor 6b) and inputs one advance angle to the controller 12. Output a signal.

  The advance angle synthesizing unit 33 includes comparators 51 and 61, integrating circuits 52 and 62 including resistors and capacitors, inverters 54 and 64, a NOR circuit 55, an AND circuit 65, an OR circuit 57, and a counter 58. In this advance angle synthesizing unit 33, two threshold values are used when the signal obtained from the sensor is binarized. The comparator 51 compares the sensor signal with the first threshold value V1. On the other hand, the comparator 61 compares the sensor signal with the second threshold value V2.

  FIG. 7 is a graph showing the waveforms of the sensor signal and the advance angle signal when two threshold values are provided. In the figure, the vertical axis represents the signal magnitude, and the horizontal axis represents the electrical angle θ. The rising edge of the sensor signal a is detected using the first threshold value V1, and the falling edge of the sensor signal a is detected using the second threshold value V2. That is, at the moment when the value of the sensor signal a becomes larger than the first threshold value V1, the binarization value is switched from L to H, and the moment when the value of the sensor signal a becomes smaller than the second threshold value V2. The binarization value is switched from H to L. The binarization value does not change at the moment when the value of the sensor signal a becomes smaller than the first threshold value V1 or the moment when the value becomes larger than the second threshold value V2.

  Here, by setting the first threshold value V1 to −sin α and the second threshold value V2 to + sin α, a signal in which an advance angle of α ° is given to the sensor signal a can be created. In general, assuming that the signal obtained from the sensor is f (θ), an advance angle of α ° is given by setting the first threshold value to f (−α) and the second threshold value to f (α). Signal can be produced.

  The advance angle synthesizing unit 33 in FIG. 6 detects the rising and falling edges of the sensor signal a, and counts the signals with the counter 58, thereby generating an advance angle signal. Similarly to the first embodiment, by changing the value of α in accordance with the rotation speed, the advance angle at each rotation speed can be optimized, and the efficiency of the motor can be increased.

  The stepping motor control device of the second embodiment has the following effects. In the first embodiment, in order to obtain the advance angle α, two position sensors that are 90 ° out of phase in electrical angle are required. On the other hand, in the second embodiment, even when there is only one position sensor, a signal with an advance angle α can be generated. Therefore, the present invention can also be applied to a type having only one position sensor, such as a fan motor in which the rotation direction of the motor is determined. Of course, a signal having two or more position sensors can generate a signal with an advance angle α.

  In the second embodiment, there is an effect that the same circuit can be used regardless of the rotation direction of the motor. Further, as described above, it is necessary to give the advance angle for improving the torque so that the energization is performed earlier than the timing shown in FIG. That is, when the motor rotation direction is positive, the advance angle must be given in the negative direction, and when the motor rotation direction is negative, the advance angle must be given in the positive direction.

  In the method of the first embodiment, the switching of the advance signal is not dependent on the rotation direction of the motor, but is determined only by the rotor angle. For this reason, it is necessary to switch the circuit according to the rotation direction of the motor so that the circuit of FIG. 4 is used when rotating in the forward direction and the circuit of FIG. 5 is used when rotating in the reverse direction.

  On the other hand, in the method of the second embodiment, since the time-differentiated sensor signal such as the rise and fall of the sensor signal is involved, the angle at which the advance signal changes is changed depending on the rotation direction of the motor. FIG. 8 is a graph showing the waveforms of the sensor signal and the advance signal when the rotation direction of the motor is the positive direction and the negative direction.

  When the motor is rotated in the positive direction, the sensor signal becomes larger than the first threshold value V1 at the point P4 and becomes smaller than the second threshold value V2 at the point P2. On the other hand, when the motor is rotated in the reverse direction, the sensor signal becomes larger than the first threshold value V1 at the point P3 and becomes smaller than the second threshold value V2 at the point P1. In this way, an advance angle for improving torque can be given without switching the circuit regardless of whether the rotation direction of the motor is positive or negative.

  The present invention is not limited to the configuration of the above-described embodiment, and any configuration can be used as long as the functions shown in the claims or the functions of the configuration of the present embodiment can be achieved. Is also applicable.

It is a perspective view which shows the structure of the stepping motor in 1st Embodiment. It is a figure which shows the structure of the motor drive circuit which drives a stepping motor. It is a graph which shows the waveform of the 1st, 2nd sensor signal and advance angle signal which are each output from the 1st sensor 6a and the 2nd sensor 6b. 3 is a circuit diagram showing a configuration of an advance angle synthesis unit 13. FIG. It is a circuit diagram which shows the structure of the advance angle synthetic | combination part 13 at the time of reversing the rotation direction of a motor. It is a figure which shows the structure of the advance angle synthetic | combination part in 2nd Embodiment. It is a graph which shows the waveform of a sensor signal and a lead angle signal when two thresholds are provided. It is a graph which shows the waveform of a sensor signal and a lead angle signal in case the rotation direction of a motor is a positive direction and a negative direction. It is a figure which shows the conventional two-phase coils A and B and the rotor 101. FIG. It is a graph which shows torque distribution at the time of flowing a fixed electric current through each phase. It is a graph which shows the time change of an excitation voltage and an excitation current. It is a graph which shows the relationship between a torque and an advance angle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stepping motor 3 Rotor 4a 1st coil 4b 2nd coil 6a 1st sensor 6b 2nd sensor 10 Motor drive circuit 12 Controller 13, 33 Lead angle synthetic | combination part

Claims (14)

A rotor having a magnet, a first coil, a second coil, and a stator that includes first and second position detecting means for detecting the position of the magnet and rotatably supports the rotor. For motor
A motor driving device for rotating the rotor by sequentially switching a current supplied to the first coil and the second coil;
A signal obtained by multiplying the signal obtained from the first position detection means by the first coefficient a1 and a signal obtained by multiplying the signal obtained from the second position detection means by the second coefficient a2 1 lead angle signal,
A signal obtained by multiplying the signal obtained from the first position detection means by the third coefficient b1 and a signal obtained by multiplying the signal obtained from the second position detection means by the fourth coefficient b2 are added to An advance angle synthesis means for generating an advance angle signal of 2;
Motor drive comprising: control means for switching energization to the first coil by the first advance angle signal and switching energization to the second coil by the second advance angle signal apparatus. The signal obtained from the first position detection means is a sine wave signal, the signal obtained from the second position detection means is a cosine wave signal,
The first coefficient a1, the second coefficient a2, the third coefficient b1, and the fourth coefficient b2 are respectively expressed as a1 = A cos α and a2 = A sin α using the amplification degree A and the advance angle α. B1 = −A sin α and b2 = A cos α.   3. The first coefficient a1, the second coefficient a2, the third coefficient b1, and the fourth coefficient b2 change according to the rotational speed of the rotor. Motor drive device. For a motor comprising a rotor having a magnet, a first coil, a second coil, and a stator that rotatably detects the position of the magnet, and a stator that rotatably supports the rotor.
A motor driving device for rotating the rotor by sequentially switching a current supplied to the first coil and the second coil;
A comparing means for comparing a voltage of a signal obtained from the position detecting means with a first threshold, and for comparing the voltage with a second threshold higher than the first threshold;
Control means for switching energization to the first coil and the second coil when the voltage exceeds the first threshold and when the threshold falls below the second threshold. The motor drive device characterized by this.   When the electrical angle θ and the advance angle α of the rotor are used and the signal obtained from the position detection means is f (θ), the first threshold value is f (−α), and the second threshold value is f. The motor driving device according to claim 4, wherein the motor driving device is (α).   The motor driving apparatus according to claim 4, wherein the first threshold value and the second threshold value change according to a rotational speed of the rotor.   The motor driving apparatus according to claim 1, wherein the position detecting unit detects magnetism of the magnet. A rotor having a magnet, a first coil, a second coil, and a stator that includes first and second position detecting means for detecting the position of the magnet and rotatably supports the rotor. For motor
A motor driving method for rotating the rotor by sequentially switching a current supplied to the first coil and the second coil,
A signal obtained by multiplying the signal obtained from the first position detection means by the first coefficient a1 and a signal obtained by multiplying the signal obtained from the second position detection means by the second coefficient a2 1 lead angle signal,
A signal obtained by multiplying the signal obtained from the first position detection means by the third coefficient b1 and a signal obtained by multiplying the signal obtained from the second position detection means by the fourth coefficient b2 are added to An advance angle synthesis step for generating an advance angle signal of 2;
And a control step of switching energization to the first coil by the first advance angle signal and switching energization to the second coil by the second advance angle signal. . The signal obtained from the first position detection means is a sine wave signal, the signal obtained from the second position detection means is a cosine wave signal,
The first coefficient a1, the second coefficient a2, the third coefficient b1, and the fourth coefficient b2 are respectively expressed as a1 = A cos α and a2 = A sin α using the amplification degree A and the advance angle α. The motor drive method according to claim 1, wherein b1 = −A sin α and b2 = A cos α.   10. The first coefficient a1, the second coefficient a2, the third coefficient b1, and the fourth coefficient b2 change according to the rotational speed of the rotor. Motor drive method. For a motor comprising a rotor having a magnet, a first coil, a second coil, and a stator that rotatably detects the position of the magnet, and a stator that rotatably supports the rotor.
A motor driving method for rotating the rotor by sequentially switching a current supplied to the first coil and the second coil,
A comparison step of comparing the voltage of the signal obtained from the position detection means with a first threshold, and comparing the voltage with a second threshold higher than the first threshold;
A control step of switching energization to the first coil and the second coil when the voltage exceeds the first threshold and when the threshold falls below the second threshold. A motor driving method.   When the electrical angle θ and the advance angle α of the rotor are used and the signal obtained from the position detection means is f (θ), the first threshold value is f (−α), and the second threshold value is f. The motor driving method according to claim 11, wherein (α).   The motor driving method according to claim 11, wherein the first threshold value and the second threshold value change according to a rotational speed of the rotor.   The motor driving method according to claim 8, wherein the position detecting unit detects magnetism of the magnet.

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