JP2013046547A - Motor control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the resolution of an estimated angle of a rectangular wave drive brushless motor by only altering the logic of a motor control device without adding any modifications to the motor, thereby making it possible to drive the motor with a sinusoidal wave.SOLUTION: In a control unit 3 of a motor control device, a pattern conversion part 12 determines a pattern number corresponding to a combination of values of rotation position signals U, V and W which are out of phase by 2π/3 rad each according to the pattern information stored in a pattern information retention part 11. An angular velocity calculation unit 15 calculates the angular velocity of a rotor per sample time from time intervals between a rise to the next rise of one rotation position signal. An intermittent angle calculation unit 13 multiplies the pattern number by π/3 rad to calculate an intermittent angle, and a continuous angle calculation part 18 adds the angular velocity to the intermittent angle every sample time to make it a continuous angle.

Description

  The present invention relates to a motor control device for obtaining a continuous rotation angle from a rotor position detection signal in a brushless motor for square wave driving and driving it in a sine wave.

  The motor control device needs to accurately detect the rotational position of the rotor in order to drive and control the brushless motor. Therefore, for example, in the rotation angle detection device according to Patent Document 1, the H level is set in synchronization with the rotation of the rotating body by the magnetic flux from the magnets arranged at equal intervals along the rotating direction of the rotating body and attached to the rotating body. Using three Hall elements that output rectangular wave-shaped signals # 1 to # 3 that change to an L level binary signal, a magnetic pole commutation logic constituted by an electric circuit is based on signals # 1 to # 3. Bit rotation angle signals A6 to A4 are generated. Then, a smoothing circuit that is also constituted by an electric circuit generates 4-bit interpolation signals A3 to A0 based on the least significant bit A4 of the rotation angle signals A6 to A4. By interpolating a 3-bit rotation angle that can be detected by three Hall elements with a 4-bit interpolation signal, the angle detection resolution is improved without increasing the number of Hall elements, and the brushless motor is driven in a sine wave.

  Further, for example, in the drive device according to Patent Document 2, three magnetic pole position detection signals that are 120 degrees out of phase are acquired from three Hall elements that detect the magnetic pole position of the rotating body, and a predetermined magnetic pole is obtained every 60 degrees. The position detection signals are selected one by one in order, and the angle range corresponding to the selected magnetic pole position detection signal is obtained from the relationship between the previously mapped interval and the angle range.

  In addition, when the rotation angle is detected and interpolated based on the signal from the Hall element as in Patent Document 1, the interpolation method is switched between when the rotor rotation speed is high and when the rotation speed is low, and calculation at high rotation is performed. A motor control apparatus that reduces the number of times has also been proposed (see, for example, Patent Document 3).

JP-A-6-265303 JP-A-9-121484 JP-A-11-215881

Since the conventional motor control device is configured as described above, in order to drive a square-wave driving brushless motor based on a high-resolution estimated angle to a sine wave, a magnetic pole commutation logic and a brushless motor are provided. It was necessary to add an electric circuit such as a smoothing circuit.
In addition, when position servo control is performed in which reversal of the rotor and a change in the rotation speed are frequently performed, there is a problem that it is difficult to detect a stable angle with respect to a sudden change of the rotor in the conventional method. Therefore, the rotational position of the rotor could not be estimated for detection, and it was difficult to rotate the brushless motor efficiently and smoothly.

  The present invention has been made to solve the above-described problems, and improves the angle resolution by changing the logic of the motor control device without modifying the brushless motor for driving the square wave, and driving the sine wave. The purpose is to let you.

  The motor control device according to the present invention includes a pattern information holding unit storing a pattern number set for each combination of rotational position signal values that can be taken while the rotor makes one electrical angle rotation, and a plurality of position detections A pattern conversion unit that uses a rotational position signal output by each unit as input and determines a pattern number corresponding to a combination of values of the input rotational position signal with reference to the pattern information holding unit; An intermittent angle calculation unit that calculates the intermittent angle of the rotor by multiplying the reference angle obtained by dividing the rotating electrical angle by the number of combinations of the rotational position signal values by the pattern number determined by the pattern conversion unit, and an input Based on the rotational position signal, an angular velocity calculation unit that calculates the amount of change in the angle of the rotor per sample time shorter than the time interval when the combination of the values of the rotational position signal changes; At each sample time, a continuous angle calculation unit that calculates the continuous angle obtained by interpolating the intermittent angle by integrating the angular variation calculated by the angular velocity calculation unit to the intermittent angle calculated by the intermittent angle calculation unit Are provided.

  According to this invention, the pattern number corresponding to the combination of the rotational position signal values is determined with reference to the pattern information holding unit, the intermittent angle is calculated by multiplying the pattern number by the reference angle, and the intermittent angle is calculated per sample time. Since the angle change amount of the rotors is integrated to calculate the continuous angle, the continuous angle can be estimated only by changing the logic of the motor control device without modifying the brushless motor for square wave driving. As a result, a brushless motor that is exclusively driven by a square wave drive can be efficiently and smoothly rotated by a sine wave drive.

It is a block diagram which shows the structure of the motor control apparatus which concerns on Embodiment 1 of this invention, and the brushless motor used as a control object. 3 is a block diagram illustrating an internal configuration of a control unit of the motor control device according to Embodiment 1. FIG. It is a figure explaining pattern information. It is a graph which shows rotation position signal U, V, and W which Hall IC outputs. It is a graph which shows the relationship between a pattern number and an intermittent angle, FIG.5 (a) shows the case where forward rotation and FIG.5 (b) are reverse rotation. FIG. 3 is a block diagram illustrating an internal configuration of an angular velocity calculation unit included in the control unit according to the first embodiment. 3 is a graph illustrating an output example of each unit in the control unit according to the first embodiment. It is a flock figure which shows the internal structure of the control part of the motor control apparatus which concerns on Embodiment 2 of this invention. 6 is a block diagram illustrating an internal configuration of an angular velocity calculation unit included in a control unit according to Embodiment 2. FIG. 10 is a graph illustrating an output example of each unit in the control unit according to the second embodiment. It is a block diagram which shows the internal structure of the control part of the motor control apparatus which concerns on Embodiment 3 of this invention. FIG. 10 is a block diagram illustrating an internal configuration of an angular velocity calculation unit and a stability evaluation unit included in a control unit according to Embodiment 3. 10 is a graph of count values and simulated values for explaining the stability evaluation unit of the third embodiment. 10 is a graph illustrating an output example of each unit in the control unit according to the third embodiment.

Embodiment 1 FIG.
A motor control device 1 shown in FIG. 1 is a device that drives and controls a brushless DC motor (BLDCM). The brushless motor 5 includes a stator 6 wound with U-phase, V-phase, and W-phase windings, and a rotor 7 that is in a position close to the stator 6, maintains a magnetic coupling relationship, and is rotatably supported. Hall ICs 8U, 8V, and 8W for detecting the rotational position (magnetic pole position) of the rotor 7 are installed. These Hall ICs 8U, 8V, and 8W are composed of integrated circuits (ICs) in which Hall elements are incorporated, and detect the magnetic poles of the magnetic pole position detection magnet that rotates integrally with the rotor 7, and correspond to the polarity of the magnetic poles. Outputs rotation position signal. The Hall ICs 8U, 8V, and 8W are disposed at a mechanical angle of π / 3 rad, and because of the number of magnetic poles 4, they are separated by an electrical angle of 2π / 3 rad. Hereinafter, all angles represent electrical angles, all angular velocities represent electrical angular velocities, and one rotation represents an electrical angle corresponding to 2π rad.

  The motor control device 1 includes a Hall IC 8U, 8V, 8W interface (hereinafter referred to as I / F) 2, a control unit 3, and a drive circuit 4. The I / F 2 inputs a rotation position signal of the Hall IC 8U through the Hall IC terminal (U), performs a predetermined amplification process, and outputs the signal to the control unit 3. Further, the I / F 2 receives the rotational position signal of the Hall IC 8V via the Hall IC terminal (V), performs a predetermined amplification process, and outputs it to the I / F 2. Further, the I / F 2 inputs a rotation position signal of the Hall IC 8W through the Hall IC terminal (W), performs a predetermined amplification process, and outputs it to the control unit 3.

  The control unit 3 is composed of an arithmetic processing circuit such as a microcomputer, and the intermittent rotation angle (hereinafter referred to as intermittent angle) of the rotor 7 indicated by the Hall ICs 8U, 8V, and 8W input from the I / F 2 is used by a method described later. A continuous rotation angle of the rotor 7 (hereinafter referred to as a continuous angle) is calculated. Then, using the calculated continuous angle, a PWM (Pulse Width Modulation) control signal indicating a drive duty ratio is generated and applied to the drive circuit 4. Note that a known method may be used for the vector control by the PWM method, and the description thereof is omitted.

  The drive circuit 4 energizes the windings of the stator 6 via the motor terminal (U), the motor terminal (V), and the motor terminal (W) at a predetermined cycle according to the PWM control signal. As a result, a sinusoidal current having a magnitude corresponding to the continuous rotation angle flows through the windings of the stator 6, and the rotor 7 can be efficiently and smoothly rotated.

Next, details of the control unit 3 will be described.
As shown in FIG. 2, the control unit 3 calculates the pattern information holding unit 11, the pattern conversion unit 12 to which the rotational position signals of the Hall ICs 8U, 8V, and 8W are input from the I / F 2, and the intermittent angle of the rotor 7. An intermittent angle calculation unit 13, a rotation direction detection unit 14 that detects the rotation direction of the rotor 7, an angular velocity calculation unit 15 that calculates an angular velocity of the rotor 7 per sample time, a multiplication unit 16, and an angular velocity that corrects the angular velocity. The integration limiting unit 17 includes a continuous angle calculation unit 18 that calculates a continuous angle from the intermittent angle and the angular velocity, and an offset angle correction unit 19 that corrects the continuous angle.
Each part of the control unit 3 operates once every predetermined sample time (for example, 0.001 sec).

  FIG. 3 is a diagram illustrating an example of pattern information (truth table) set in the pattern information holding unit 11. The pattern information represents the correspondence between the combination of the rotation position signal values (H, L) of the Hall ICs 8U, 8V, 8W and the pattern numbers (1-6).

FIG. 4 is a graph showing an example of rotation position signals of the Hall ICs 8U, 8V, and 8W. 4A shows the rotational position signal U output from the Hall IC 8U, FIG. 4B shows the rotational position signal V output from the Hall IC 8V, and FIG. 4C shows the rotational position signal W output from the Hall IC 8W. In each graph, the vertical axis represents signal values and the horizontal axis represents time. Hall ICs 8U, 8V, and 8W detect changes in the magnetic poles N and S of the rotor 7 side magnet to change the signal levels H and L. Due to the arrangement positions of the Hall ICs 8U, 8V, and 8W, respectively. The signal is shifted in phase by 2π / 3 rad in electrical angle. In this example, the angle signal repeat pattern makes a round at a time interval (2π rad in electrical angle) from the rising edge of the rotational position signal to the next rising edge.
For example, at the sample time T1 in FIG. 4, the rotational position signal U is H, the rotational position signal V is L, and the rotational position signal W is H. Therefore, according to the pattern information of FIG. . At the sample time T2, since the combination of the rotational position signals U, V, W is HLL, the pattern number is 2. In this way, if the rotor 7 is continuously rotating in the positive direction, the pattern numbers change in ascending order of 1 to 6 with time, and when reversed and rotated in the middle, the pattern numbers also change in descending order of 6 to 1. To do. The pattern number takes only an integer of 1 to 6. When the pattern number increases from 6, it changes to 1, and when it continues to increase, 1 → 6 is repeatedly circulated. On the other hand, when it decreases from 1, it changes to 6, and when it continues further decreasing, 6 → 1 is circulated repeatedly.

  The pattern conversion unit 12 refers to the pattern information in the pattern information holding unit 11 and determines a pattern number corresponding to the combination of the rotational position signals U, V, and W input from the I / F 2 for each sample time. The determined pattern number is output to the intermittent angle calculation unit 13, the rotation direction detection unit 14, and the angular velocity integration limiting unit 17.

The rotation direction detection unit 14 determines the rotation direction of the rotor 7 by comparing the pattern number input from the pattern conversion unit 12 with the pattern number input last time. Specifically, the rotation direction detection unit 14 subtracts the previous input value from the current input value, and determines that the rotation is in the forward direction if the difference is 1 or -5, and the rotation in the reverse direction if the difference is -1 or 5. To do.
Then, 1 is output to the intermittent angle calculation unit 13 from the rotation direction detection unit 14 and 0 is output in the case of reverse rotation. Further, 1 is output from the rotation direction detection unit 14 to the multiplication unit 16, and 1 is output in the case of reverse rotation.

The intermittent angle calculation unit 13 multiplies the pattern number input from the pattern conversion unit 12 by π / 3 rad to calculate an intermittent rotation angle every time the rotational position signals U, V, and W change, It outputs to the continuous angle calculation unit 18. As shown in FIGS. 3 and 4, there are six combinations of H and L of the three rotational position signals U, V, and W during one rotation of the rotor 7. That is, since the combination of H and L changes every π / 3 rad (= 2π rad / 6 ways), the intermittent angle of the rotor 7 can be set at a resolution π / 3 rad by multiplying the pattern number by π / 3 rad. I want.
That is, in the example of the first embodiment, π / 3 rad obtained by dividing the electrical angle 2π rad at which the rotor 7 rotates once by 6 which is the maximum value of the pattern number is the reference angle.

  However, since the change in the combination of the rotational position signals U, V, and W occurs every π / 3 rad, the detection timing differs between forward rotation and reverse rotation. Therefore, the intermittent angle calculation unit 13 subtracts 1 or 0 input from the rotation direction detection unit 14 from the pattern number, and multiplies the subtracted pattern number by π / 3. Therefore, in the case of reverse rotation, the value obtained by multiplying the pattern number by π / 3 rad as it is is the intermittent angle. On the other hand, in the case of forward rotation, a value smaller by π / 3 rad than the value obtained by multiplying the pattern number by π / 3 rad is the intermittent angle.

FIG. 5A is a graph showing the relationship between the pattern number and the intermittent angle for forward rotation, and FIG. 5B is a graph showing the relationship between the pattern number and the intermittent angle for reverse rotation. In both graphs, the vertical axis represents the rotation angle (rad) of the rotor 7 and the horizontal axis represents the pattern number. Moreover, a continuous line shows an intermittent angle and a broken line shows a continuous angle. This continuous angle is a value obtained by estimating the actual angle of the rotor 7.
In the case of forward rotation, since the intermittent angle is calculated by (pattern number −1) · π / 3, the intermittent angle between pattern numbers 1 → 2 is 0 (and 2π) as shown in FIG. Π / 3 between pattern numbers 2 → 3, 2π / 3 between pattern numbers 3 → 4, π between pattern numbers 4 → 5, 4π / 3 between pattern numbers 5 → 6, 5π between pattern numbers 6 → 1 / 3.
On the other hand, in the case of reverse rotation, since the intermittent angle is calculated as (pattern number) · π / 3, as shown in FIG. 5B, the intermittent angle between pattern numbers 6 → 5 is 2π, pattern number 5 → 5π / 3 during pattern 4, 4π / 3 between pattern number 4 → 3, π between pattern number 3 → 2, 2π / 3 between pattern number 2 → 1, and π / 3 between pattern number 1 → 6. .

The angular velocity calculation unit 15 calculates an angular velocity (rad / sec) per sample time using at least one of the rotational position signals U, V, and W, and outputs the angular velocity to the multiplication unit 16. Details of the angular velocity calculation unit 15 will be described later.
This angular velocity corresponds to the amount of change in the angle of the rotor 7 per sample time.

  The multiplication unit 16 multiplies the angular velocity per sample time input from the angular velocity calculation unit 15 by 1 (during forward rotation) or −1 (during reverse rotation) input from the rotation direction detection unit 14 to limit angular velocity integration. To the unit 17.

  The angular velocity integration limiting unit 17 integrates the angular velocity input from the multiplication unit 16 for a period until the pattern number input from the pattern conversion unit 12 changes, and limits the integrated value to ± π / 3. Specifically, when the integrated value is within a range of ± π / 3, the angular velocity input from the multiplying unit 16 is output to the continuous angle calculating unit 18 as it is, and the integrated value is π / 3 or more or −π / 3 or less. In case of, do not output. Thus, in FIG. 5A, for example, during pattern number 2 → 3, the integrated value of the angular velocity is prevented from exceeding π / 3, and the continuous angle is prevented from being overcorrected to 2π / 3 rad or more. Yes. Similarly, in FIG. 5B, for example, during the pattern number 5 → 4, the integrated value of the angular velocity is prevented from being −π / 3 or less, and the continuous angle is prevented from being overcorrected to 4π / 3 rad or less. doing.

  The continuous angle calculation unit 18 integrates the angular velocity (rad / sec) per sample time input from the angular velocity integration limiting unit 17 for each sample time to the intermittent angle for each π / 3 rad input from the intermittent angle calculation unit 13. Continue (subtract if reverse rotation), and calculate the continuous angle. As a result, as shown in FIG. 5, a sinusoidal continuous angle obtained by interpolating the square-wave intermittent angle can be obtained.

The offset angle correction unit 19 performs offset correction by adding an offset angle indicating a deviation of the initial position of the rotor 7 to the continuous angle input from the continuous angle calculation unit 18, and when the corrected continuous angle is 0 or less Output with 2π added. On the other hand, if the corrected continuous angle is 2π or more, 2π is subtracted and output. This limits the continuous angle within the range of 0 to 2π.
Note that the actual initial positional deviation of the rotor 7 is set in the offset angle correction unit 19 as the offset angle.

Next, details of the angular velocity calculation unit 15 will be described.
FIG. 6 is a block diagram showing the internal configuration of the angular velocity calculation unit 15. The angular velocity calculation unit 15 selects and outputs one of the rotational position signals U, V, and W input from the I / F 2 and a rising detection unit 22 that detects the rising of the signal. A time interval measuring unit 23 that counts a time interval from one rising to the next rising, a time interval correcting unit 24 that limits the time interval within an appropriate range, and an angular velocity converting unit 25 that converts the time interval into an angular velocity. Composed. The angular velocity per sample time converted by the angular velocity converting unit 25 is output to the continuous angle calculating unit 18 described above.
In the angular velocity calculation unit 15, each unit operates once every predetermined sample time (for example, 0.001 sec).

  The signal switching unit 21 selects any one of the rotational position signals U, V, and W and outputs the selected signal to the rising edge detection unit 22. Hereinafter, the case where the rotational position signal U is output will be described as an example, but the same applies to the case where the rotational position signal V and the rotational position signal W are output.

  The rising edge detection unit 22 compares the value of the rotational position signal U input from the signal switching unit 21 with the previous input value at each sampling time, and detects a rising edge that changes from L to H. The rising edge detection unit 22 may detect a falling edge that changes from H to L. The rising edge detection unit 22 outputs a rising signal to the pulse count unit 23 every time a rising edge or a falling edge is detected.

The time interval measurement unit 23 starts counting when receiving a rising signal from the rising detection unit 22, and counts up the count value every sample time. When the next rising signal is received, the count value at that time is output to the time interval correction unit 24, the count value is reset, and the count-up is started again.
Therefore, the count value represents a time interval of one pulse period from the rising edge of the rotational position signal U to the next rising edge, and the count value increases as the rotational speed of the rotor 7 decreases.

The time interval correction unit 24 outputs the count value input from the time interval measurement unit 23, that is, the time interval to the angular velocity conversion unit 25 as it is if it is within the proper range, and sets the time interval if it is above or below the proper range. Instead, the upper limit value or lower limit value of the appropriate range is output.
The upper limit value and lower limit value of the appropriate range are set in advance in the time interval correction unit 24. Here, the lower limit value is set to 0 so that the time interval does not become a negative value. The upper limit value is a time interval value corresponding to the minimum rotational speed necessary for starting the brushless motor 5. When the brushless motor 5 is started, the rotation speed of the rotor 7 is 0 and the pulse of the rotation position signal U is not generated. Therefore, if the time interval measuring unit 23 continues to count up during this time, it overflows or the rotor 7 is rotated. Necessary excitation current may not flow. In order to prevent this, the minimum rotation speed of the rotor 7 is secured by the upper limit value, and torque is reliably generated even at low rotation.

  The angular velocity conversion unit 25 divides the electrical angle 2πrad at which the rotor 7 makes one rotation by the count value of the corrected pulse interval input from the time interval correction unit 24 to obtain an angular velocity (rad / sec), that is, per sample time. The amount of change in angle is calculated. In this way, the angular velocity is calculated for each pulse period of the rotational position signal U and is output to the multiplication unit 16. The angular velocity calculated in the current pulse cycle is used for the continuous angle calculation of the continuous angle calculation unit 18 in the next pulse cycle.

  As described above, the angular velocity calculation unit 15 measures the pulse period of the rotational position signal in order to detect the rotational speed of the rotor 7, but here, only the rotational position signal U output from the U-phase Hall IC 8U is used. Measuring. Therefore, it is possible to eliminate the influence of variations of the Hall ICs 8U, 8V, and 8W due to the arrangement of the Hall ICs 8U, 8V, and 8W, the sensitivity of the Hall ICs 8U, 8V, and 8W, and the magnetization of the rotor 7 side magnet. Further, since only the rising edge is detected, the rotational speed does not vary even if the ratio of H and L of the rotational position signal is not 50:50.

  FIG. 7 shows an output example of each part of the control unit 3. FIG. 7A is a graph of the continuous angle output from the offset angle correction unit 19. The solid line indicates the continuous angle, and the broken line indicates the actual angle of the rotor 7. FIGS. 7B to 7D are graphs of the rotational position signals U, V, and W output from the Hall ICs 8U, 8V, and 8W. FIG. 7E shows the pattern number (output of the pattern conversion unit 12) and the direction of the rotation direction (output of the rotation direction detection unit 14) corresponding to the combination of the values of the rotation position signals U, V, and W. FIG. 7F shows a pulse indicating a rising signal of the rotational position signal U in the rising detection unit 22. FIG. 7G is a graph of the angular velocity output from the angular velocity conversion unit 25. FIG. 7G shows a graph of the change in angular velocity with time, but the actual output of the angular velocity calculation unit 15 is the average value of the angular velocities in the time interval C1 from one rise to the next rise. The same applies to the time interval C2 and thereafter.

  The pattern conversion unit 12 determines the pattern number as shown in FIG. 7E from the combination of the values of the rotational position signals U, V, and W. Then, the rotation direction detection unit 14 determines whether the rotation direction is normal or reverse based on a comparison between the previous and current pattern numbers. For example, the periods P1 to P3 in which the pattern numbers change from 1 to 6 in ascending order are determined to be normal rotation, the pattern number changes from 6 to 5 at the end of the period P3, and then the period P4 changes in descending order. The reverse rotation is determined. Furthermore, a period P5 in which the pattern number changes from 1 to 2 at the end of the period P4 and then changes in ascending order is determined to be normal rotation. In this way, the pattern number and the rotation direction are obtained.

  Subsequently, the intermittent angle calculation unit 13 calculates (pattern number-1) · π / 3 for the forward rotation and calculates the pattern number · π / 3 for the reverse rotation to obtain the intermittent angle. Then, the continuous angle calculation unit 18 adds or subtracts the angular velocity per sample time obtained by the angular velocity calculation unit 15 and input through the multiplication unit 16 and the angular velocity integration limiting unit 17 to the intermittent angle, thereby obtaining the continuous angle. Ask.

In the following description, it is assumed that there is no deviation in the initial position of the rotor 7 (offset angle 0 rad), and correction by the offset angle correction unit 19 is not considered.
For example, in the positive rotation period P3, the intermittent angle calculation unit 13 calculates the intermittent angle 0 rad = (1-1) · π / 3 at the sample time when the pattern number 1 is determined. Subsequently, the continuous angle calculation unit 18 adds the positive angular velocity c2 per sample time calculated based on the time interval C2 to the intermittent angle 0 rad, so that the angle continuously increases. The continuous angle is calculated as it is, and when pattern number 2 is determined at a certain sample time, the intermittent angle calculation unit 13 calculates the intermittent angle π / 3 rad = (2-1) · π / 3. Then, the continuous angle calculation unit 18 adds the angular velocity c2 to the intermittent angle 2π / 3 every sampling time, and obtains a continuous angle.

  Similarly, the intermittent angle 5π / 3 rad = (6-1) · π / 3 is calculated for the pattern number 6 in the period P3, and the angular velocity c2 is added every sample time. Since the rotational speed of the rotor 7 becomes slow in the meantime and does not change easily to the next pattern number, the integrated value of the angular velocity c2 added to the intermittent angle becomes equal to or higher than the intermittent angle resolution π / 3, and the continuous angle is 2πrad. Will be exceeded. Therefore, when the integrated value of the angular velocity c2 becomes π / 3 or more in the angular velocity integration limiting unit 17, the output of the angular velocity c2 to the continuous angle calculating unit 18 is stopped. As a result, the angular velocity c2 is not added any more, and the continuous angle remains 2π rad until the pattern number changes to the next (arrows a and b in FIG. 7A).

When the pattern number changes from 6 to 5, reverse rotation is detected (from the period P3 to P4), and the intermittent angle calculation unit 13 calculates the intermittent angle 5π / 3 rad = 5 · π / 3 in the reverse rotation period P4. And output to the continuous angle calculator 18. Therefore, at the sample time when the pattern number is changed from 6 to 5, the continuous angle is changed from 2πrad to 5π / 3 rad (arrows b and c in FIG. 7A). Since the negative angular velocity c2 is added to the intermittent angle 5π / 3 rad every successive sample time, the angle continuously decreases.
However, since the rotational speed of the rotor 7 is slow and does not change easily to the next pattern number, the angular velocity integration limiting unit prevents the integrated value of the angular velocity c2 from being −π / 3 or less and the continuous angle from being 4π / 3 rad or less. 17 limits the output of the angular velocity c2. Thereby, the continuous angle becomes constant in the middle of the pattern number 5 (arrows d and e in FIG. 7A).

In the case of reverse rotation, the angular velocity used in pattern numbers 5 and 4 in the first half of period P4 (before arrow f in FIG. 7A) was angular velocity c2 obtained at time interval C2, but changed from pattern number 4 to 3. Since the rising edge of the rotational position signal U is detected at the timing of the rotation, the angular velocities used in the pattern numbers 3 to 1 (and the pattern numbers 2 to 6 in the next period P5) after the arrow f in FIG. The angular velocity c3 obtained in C3 is obtained.
As described above, the angular velocity used to interpolate the intermittent angle to the continuous angle is a value obtained from the previous time interval. Therefore, when the rotational speed of the rotor 7 changes rapidly, the angular velocity is slightly different from the continuous angle and the actual angle. However, in the state where the rotational speed of the rotor 7 is constant and stable as in the period P9 and after, the continuous angle closely follows the actually measured angle.
In addition, when the motor control device 1 is applied to the brushless motor 5 whose rotation direction is reversed, the tracking of the continuous angle after shifting from reverse rotation to normal rotation tends to be delayed. It is more suitable for detecting the angle of the brushless motor 5 that rotates at a high speed.

  As described above, according to the first embodiment, the motor control device 1 is set for each combination of values of the rotational position signals U, V, and W that can be taken while the rotor 7 makes one revolution at an electrical angle of 2π rad. 6 using the rotational position signals U, V, and W output from the three Hall ICs 8U, 8V, and 8W, respectively, as input. A pattern conversion unit 12 that determines a pattern number corresponding to a combination of the values of the signals U, V, and W with reference to the pattern information holding unit 11, and an electrical angle 2πrad at which the rotor 7 makes one rotation is a pattern number maximum value 6. Multiplying the divided reference angle π / 3 rad by the pattern number determined by the pattern conversion unit 12 to calculate the intermittent angle of the rotor 7 and the input rotational position signals U, V, Based on the angular velocity calculation unit 15 for calculating the angular velocity of the rotor 7 per sample time shorter than the time interval at which the combination of the values of the rotational position signals U, V, and W changes, and the intermittent angle calculation unit 13 for each sample time. The angular velocity per sample time calculated by the angular velocity calculating unit 15 is added to the calculated intermittent angle, and the continuous angle calculating unit 18 calculates a continuous angle obtained by interpolating the intermittent angle. For this reason, it is possible to estimate the continuous angle only by changing the logic of the control unit 3 without adding a modification as in Patent Document 1 such as adding a new electric circuit to the brushless motor 5 for driving the square wave. As a result, the brushless motor 5 that is exclusively driven by the square wave drive can be efficiently and smoothly rotated by the sine wave drive.

  Further, according to the first embodiment, the motor control device 1 includes the rotation direction detection unit 14 that detects the rotation direction of the rotor 7 according to the increase / decrease of the pattern number determined by the pattern conversion unit 12, and the intermittent angle calculation unit. 13, when reverse rotation is detected by the rotation direction detection unit 14, a value obtained by multiplying the pattern number by π / 3 rad is an intermittent angle, and when positive rotation is detected, a value π / 3 rad smaller than the intermittent angle is an intermittent angle. The continuous angle calculation unit 18 accumulates positive angular velocities when the rotation direction detection unit 14 detects normal rotation of the brushless motor 5 that rotates forward and reverse, and calculates negative angular velocities when reverse rotation is detected. It was configured to accumulate. For this reason, the rotational direction of the rotor 7 can be detected every π / 3 rad, and stable drive control is possible even if frequent inversion occurs.

  Further, according to the first embodiment, the motor control device 1 is configured such that the time interval from the rise of the value of the rotational position signal U output by the Hall IC 8U among the three Hall ICs 8U, 8V, 8W to the next rise, or A time interval measuring unit 23 that measures a time interval from one falling to the next falling is provided, and the angular velocity calculating unit 15 divides the time interval measured by the time interval measuring unit 23 by an electrical angle 2π rad at which the rotor 7 rotates once. Thus, the angular velocity of the rotor 7 per sample time is calculated. For this reason, when the motor control device 1 is applied to the brushless motor 5 that continuously rotates in the same direction, the rotational position signal U due to the arrangement and sensitivity of the Hall ICs 8U, 8V, 8W, the magnetization of the rotor 7 side magnet, and the like. , V, and W can be eliminated, and the brushless motor 5 can be rotated more efficiently and smoothly.

  Further, according to the first embodiment, the motor control device 1 limits the time interval measured by the time interval measuring unit 23 to the upper limit value of the time interval corresponding to the minimum rotation speed at which the brushless motor 5 can be activated. A time interval correction unit 24 is provided. For this reason, the starting torque can be appropriately generated even when the rotor 7 rotates at a low speed.

Embodiment 2. FIG.
FIG. 8 is a block diagram showing a configuration of the control unit 3a according to the second embodiment. FIG. 9 is a block diagram showing an internal configuration of the angular velocity calculation unit 15a according to the second embodiment. 8 and 9, the same or corresponding parts as those in FIGS. 2 and 6 are denoted by the same reference numerals and description thereof is omitted.
In the first embodiment, the angular velocity is updated at the timing of detection of the rising or falling edge of the rotational position signal U, and it has been shown that it is advantageous for a brushless motor that performs continuous rotation without inversion. . On the other hand, in a motor that performs servo control, inversion and rotation speed change frequently occur, so it is desirable to further improve the responsiveness. Therefore, in the second embodiment, the rotational position signals U, V, and W are used for updating the angular velocity to increase the responsiveness.

As shown in FIG. 8, the pattern conversion unit 12a also outputs a pattern number corresponding to the combination of the values of the rotational position signals U, V, and W to the angular velocity calculation unit 15a.
As shown in FIG. 9, the angular velocity calculation unit 15a includes a pattern transition detection unit 30, a time interval measurement unit 23a, a time interval correction unit 24, and an angular velocity conversion unit 25a. The pattern transition detection unit 30 detects the transition of the pattern number input from the pattern conversion unit 12a, and notifies the time interval measurement unit 23a every time it is detected. The time interval measurement unit 23a starts counting upon receiving notification of pattern number change detection from the pattern transition detection unit 30, and counts up the count value every sample time. When the next pattern number change detection notification is received, the count value at that time is output to the time interval correction unit 24, the count value is reset, and the count-up is started again.
Therefore, the count value represents a time interval in which the combination of the values of the rotational position signals U, V, and W output from the three Hall ICs 8U, 8V, and 8W changes, and the count value increases as the rotational speed of the rotor 7 decreases. Become.

  The angular velocity conversion unit 25a calculates the angular velocity (rad / sec) per sample time by dividing the electrical angle π / 3 rad by the corrected count value input from the time interval correction unit 24. In this way, the angular velocity is calculated every time the pattern number changes and is output to the multiplication unit 16. The angular velocity calculated in the current pattern number is used for the continuous angle calculation of the continuous angle calculation unit 18 at the next pattern number.

  FIG. 10 shows an output example of each unit of the control unit 3a according to the second embodiment. FIG. 10A is a graph of the continuous angle output from the offset angle correction unit 19. The solid line indicates the continuous angle, and the broken line indicates the actual angle of the rotor 7. FIG. 10B is a pulse showing the change detection timing of the pattern number in the pattern transition detection unit 30. The graphs of the rotational position signals U, V, and W output from the Hall ICs 8U, 8V, and 8W are the same as those in FIGS. 7B to 7D, and the values of these rotational position signals U, V, and W are the same. The pattern number (output of the pattern conversion unit 12a) and the direction of the rotation direction (output of the rotation direction detection unit 14) corresponding to the combination are the same as those in FIG.

  As shown in FIG. 10 (b), the angular velocity is obtained for each pulse that is output every time a change in the pattern number is detected. Therefore, when the rotational speed of the rotor 7 decreases, the pulse period of the rotational position signal U ends. The angular velocity can be updated immediately without waiting. Therefore, compared with the graph of FIG. 7A, the continuity angle (solid line) of the graph of FIG. 10A is more responsive to changes in the rotational speed and direction of the rotor 7. I understand that.

  As described above, according to the second embodiment, the motor control device 1 detects the change in the combination of the values of the rotational position signals U, V, and W output from the three Hall ICs 8U, 8V, and 8W, respectively. 30 and a time interval measurement unit 23a that measures a time interval from the detection of the pattern transition detection unit 30 to the next detection, and the angular velocity calculation unit 15a sets the time interval measured by the time interval measurement unit 23a to π / 3 rad. And the angular velocity of the rotor 7 per sample time is calculated. For this reason, the responsiveness of the continuous angle with respect to the actual angle of the rotor 7 can be improved, and the brushless motor 5 that rotates forward and reverse can be rotated more efficiently and smoothly.

Embodiment 3 FIG.
FIG. 11 is a block diagram illustrating a configuration of the control unit 3b according to the third embodiment. FIG. 12 is a block diagram showing an internal configuration of the angular velocity calculation unit 15b and the stability evaluation unit 40 according to the third embodiment. 11 and 12, the same or corresponding parts as those in FIGS. 2 and 6 are denoted by the same reference numerals, and the description thereof is omitted.
In the third embodiment, the controller 3 of the first embodiment obtains a smooth angle output even when the rotational position signals U, V, and W vary when the rotational speed of the rotor 7 is stable. Thus, the torque ripple of the brushless motor 5 is improved.

As shown in FIG. 11, the control unit 3b newly adds a stability evaluation unit 40 that determines whether or not the rotational speed of the rotor 7 is stable, a stable continuous angle calculation unit 41 that calculates an angular velocity at the time of stability, And an output switching unit 42 that switches between the output of the offset angle correction unit 19 and the output of the stable continuous angle calculation unit 41 according to the determination result of the stability evaluation unit 40.
As shown in FIG. 12, in the angular velocity calculation unit 15b, the rising detection unit 22b converts the rising signal indicating the detection timing of the rising edge (or falling edge) of the rotational position signal U into the stability evaluating unit 40 and the stable continuous angle. Output to the calculation unit 41. Further, the time interval measurement unit 23 b outputs a count value for each sample time to the stability evaluation unit 40.

  The stability evaluation unit 40 includes addition units 43 and 44, multiplication units 45 and 46, an annealing value holding unit 47, and a comparison unit 48. In the stability evaluation unit 40, when the count value for each sample time changes suddenly, the smoothing calculation is performed by the multiplication units 45 and 46 and the addition unit 44 so as to moderate the change in the value before and after the sudden change. The value is held in the smoothed value holding unit 47. Then, the adding unit 43 calculates the difference between the previous sample time and the smoothed value held by the smoothed value holding unit 47 and the count value of the current sample time. Further, the comparison unit 48 compares the absolute value of the difference with a preset threshold value, and determines that the rotational speed of the rotor 7 is stable if the absolute difference value is equal to or less than the threshold value. On the other hand, if the absolute difference value is larger than the threshold value, it is determined that the rotation speed is not stable, that is, suddenly changes.

As the annealing calculation, for example, as shown in FIG. 12, the multiplication unit 45 multiplies the count value of the current sample time by the averaging factor 0.5, and the multiplication unit 46 holds the smoothed value holding unit 47. The smoothing value of the previous sample time is multiplied by the smoothing coefficient 0.5, and each value is added by the adder 44 to obtain the smoothed value of the current sample time. The calculated annealing value is held in the annealing value holding unit 47. However, in accordance with the count value being reset by the rising signal in the time interval measurement unit 23, the smoothing value held by the rising signal is also reset by the smoothing value holding unit 47.
The annealing calculation may be performed by a method other than this, or may be a filter process.

  FIG. 13 illustrates a graph for comparing the count value with the spoof value. The horizontal axis of the graph is the time, the vertical axis is the count value, the broken line is the count value input from the time interval measurement unit 23 to the stability evaluation unit 40, and the solid line is the annealing value held in the annealing value holding unit 47 Indicates. Even if the count value changes suddenly as indicated by arrows g and h in FIG. 13, the smoothed value changes gently, so that the absolute difference value between the count value and the smoothed value increases. On the other hand, when the count value is stable as indicated by arrows i and j in FIG. 13, the absolute difference value from the smoothed value becomes small. Therefore, for example, if the threshold value is set to 20, it can be determined that the rotation speed of the rotor 7 is changing rapidly near the arrows g and h, and the rotation speed of the rotor 7 can be determined near the arrows i and j. .

  In FIG. 11, a stable continuous angle calculation unit 41 accumulates angular velocities per sample time (a positive value during forward rotation and a negative value during reverse rotation) input from the multiplying unit 16, and continues in a stable state. The angle is output to the output switching unit 42. The stable-time continuous angle calculation unit 41 receives a rising signal (or falling signal) of the rotational position signal U (or V, W) from the rising detection unit 22b of the angular velocity calculation unit 15b, and rises the rotational position signal U. Every time the integrated value of angular velocity is reset.

  Based on the determination result input from the stability evaluation unit 40, the output switching unit 42 externally outputs the continuous angle calculated by the stable continuous angle calculation unit 41 when the rotational speed of the rotor 7 is stable. On the other hand, when the rotational speed changes suddenly, the continuous angle calculated by the offset angle correction unit 19 is output to the outside.

FIG. 14 shows an output example of the control unit 3b according to the third embodiment. FIG. 14A is a graph of the continuous angle output from the output switching unit 42, where the solid line indicates the continuous angle and the broken line indicates the actual angle of the rotor 7. Further, in order to explain the effect of the third embodiment, a graph of the continuous angle output from the offset angle correction unit 19 is shown in FIG. 14B as a comparison. 14C to 14E are graphs of the rotational position signals U, V, and W output from the Hall ICs 8U, 8V, and 8W.
Originally, the Hall ICs 8U, 8V, and 8W are arranged at equal intervals of 2π / 3 rad in electrical angle. In this example, however, the Hall ICs 8U, 8V, and 8W are arranged at positions shifted from each other, as shown in FIGS. 14 (c) to 14 (e). As described above, the phases of the rotational position signals U, V, and W are not evenly shifted by π / 3 rads, and a phase shift occurs. However, the phase shift is steady and the rotational speed of the rotor 7 is stable. Therefore, the stability evaluation unit 40 determines that the state is stable. In addition to the positional deviations of the Hall ICs 8U, 8V, and 8W, the phase deviation also occurs due to the influence of variations due to, for example, the sensitivity of the Hall ICs 8U, 8V, and 8W and the magnetization of the rotor 7 side magnet.

In FIG. 14B, the continuous angle indicated by the solid line is calculated by the same method as in the first embodiment. Since the actual angle indicated by the broken line changes constantly, the angular velocity per sample time obtained using the time interval from the rise of the rotational position signal U to the next rise is equal to the actual angular velocity. However, since there is a phase shift, the continuous angle and the actual angle at the timing of pattern number 6 → 1 that changes in accordance with the rise of the rotational position signal U, as marked by the arrow k in FIG. Deviation occurs.
In addition, since the time interval at which the combination of the values of the rotational position signals U, V, and W changes is not equal, the integrated value becomes π / 3 rad during the integration of the angular velocity to the intermittent angle in the case of a pattern number having a long time interval. As a result, the value is limited by the angular velocity integration limiting unit 17 (arrow l in FIG. 14B). Furthermore, in the case of a pattern number with a short time interval, the value changes to the next pattern number in the middle of accumulating the angular velocity per sample time to the intermittent angle, and the value changes rapidly to the next intermittent angle. (Arrow m in FIG. 14B).
Thus, even if the rotational speed of the rotor 7 is stable, if the waveforms of the rotational position signals U, V, and W vary, the continuous angle output from the offset angle correction unit 19 deviates from the actual angle, and torque It can cause ripple.

On the other hand, in FIG. 14A, since the actual angle indicated by the broken line changes constantly, the angular velocity per sample time obtained using the time interval from the rise of the rotational position signal U to the next rise is the actual value. It becomes equal to the angular velocity. This is the same as FIG.
In the third embodiment, the steady-state continuous angle calculation unit 41 accumulates angular velocities from 0 rad every sample time during the period from the rising edge of the rotational position signal U to the next rising edge. The slope of is coincident with the slope of the actual angle. However, since a phase shift has occurred, the reset timing of the continuous angle in accordance with the rise of the rotational position signal U deviates from the timing at which the actual angle becomes 0 rad (arrow n in FIG. 14A), but the rotor 7 If the motor is rotating stably, the operation of the brushless motor 5 is not affected, and the drive can be controlled with high accuracy without torque ripple.

  In the third embodiment, the angle estimation method is switched depending on the stability of the rotation of the rotor 7, so that a more accurate continuous angle can be calculated at the stable time. On the other hand, in the configuration in which the angle estimation method is switched depending on the rotational speed of the rotor 7 as described in Patent Document 3, the rotational speed is not always stable even at high or low speed. Therefore, there are cases where accurate angle calculation cannot be performed.

  In the example of FIG. 14, the case where the rotational speed of the rotor 7 is stabilized while the brushless motor 5 is rotating forward has been described, but the stable angular speed is also obtained when the rotor 7 is stabilized while rotating backward. The output of the calculation unit 41 can be switched. In the case of reverse rotation, the stable angular velocity calculation unit 41 subtracts the negative angular velocity input from the multiplication unit 16 from 2πrad every sampling time during the period from the rising to the next rising of the rotational position signal U, and continuously Calculate the angle.

  As described above, according to the third embodiment, the motor control device 1 determines whether or not the rotational speed of the rotor 7 is stable based on the amount of change per sample time of the time interval measured by the time interval measuring unit 23b. The angular velocity per sample time calculated by the stability evaluation unit 40 and the angular velocity calculation unit 15b is determined from the rise of the value of the rotational position signal U output by the Hall IC 8U among the three Hall ICs 8U, 8V, and 8W. The period of time until the rising edge or the period from the falling edge to the next falling edge is integrated for each sampling time, and the stable continuous angle calculating section 41 for calculating the continuous angle and the stability evaluating section 40 are stable. When it is determined, the output switching unit 4 switches to the continuous angle calculation unit 41 when stable, and when it is determined that it is not stable, the output switching unit 4 switches to the continuous angle calculation unit 18 (continuous angle correction unit 19). It was configured with and. For this reason, when the rotor 7 is rotating stably, even if there are variations in the rotational position signals U, V, W, a smooth continuous angle output can be obtained, and torque ripple can be improved.

In the present invention, within the scope of the invention, any combination of the embodiments, or any modification of any component in each embodiment, or omission of any component in each embodiment is possible. .
Moreover, the motor control apparatus 1 should just change the logic of the control part 3 suitably according to structures, such as the number of Hall ICs which the brushless motor 5 has, the magnetic pole number of a rotor side magnet.

  DESCRIPTION OF SYMBOLS 1 Motor control apparatus, 2 I / F, 3, 3a, 3b Control part, 4 Drive circuit, 5 Brushless motor, 6 Stator, 7 Rotor, 8U, 8V, 8W Hall IC, 11 Pattern information holding part, 12, 12a pattern Conversion unit, 13 Intermittent angle calculation unit, 14 Rotation direction detection unit, 15, 15a, 15b Angular velocity calculation unit, 16 Multiplication unit, 17 Angular velocity integration limiting unit, 18 Continuous angle calculation unit, 19 Offset angle correction unit, 21 Signal switching unit , 22, 22b Rise detection unit, 23, 23a, 23b Time interval measurement unit, 24 hour interval correction unit, 25, 25a Angular velocity conversion unit, 30 Pattern transition detection unit, 40 Stability evaluation unit, 41 Stable continuous angle calculation unit , 42 output switching unit, 43, 44 addition unit, 45, 46 multiplication unit, 47 smoothed value holding unit, 48 comparison unit.

Claims (8)

A motor control device including a control unit that drives and controls a brushless motor that has a plurality of position detection units that are arranged along the rotation direction of the rotor and output a rotation position signal corresponding to the rotation position of the rotor,
The controller is
A pattern information holding unit storing a pattern number set for each combination of values of the rotational position signal that can be taken while the rotor makes one rotation at an electrical angle;
A pattern that uses the rotational position signals output by the plurality of position detection units as inputs, and determines a pattern number corresponding to a combination of values of the input rotational position signals with reference to the pattern information holding unit A conversion unit;
Intermittent calculation of the intermittent angle of the rotor by multiplying the pattern number determined by the pattern converter by a reference angle obtained by dividing the electrical angle of one rotation of the rotor by the number of combinations of the values of the rotational position signal An angle calculator;
Based on the input rotational position signal, an angular velocity calculation unit that calculates an angular change amount of the rotor per sample time shorter than a time interval in which a combination of values of the rotational position signals changes;
For each sample time, the angular change amount calculated by the angular velocity calculation unit is added to the intermittent angle calculated by the intermittent angle calculation unit, and a continuous angle obtained by interpolating the intermittent angle is obtained. A motor control apparatus comprising: a continuous angle calculation unit for calculating. For a brushless motor that rotates forward and backward, a rotation direction detection unit that detects the rotation direction of the rotor according to the increase or decrease of the pattern number determined by the pattern conversion unit,
When the rotation angle detection unit detects reverse rotation, the intermittent angle calculation unit sets a value obtained by multiplying the pattern number by a reference angle as an intermittent angle, and when positive rotation is detected, the intermittent angle calculation unit calculates the intermittent angle from the intermittent angle. 2. The motor control device according to claim 1, wherein a value having a small reference angle is an intermittent angle. For a brushless motor that rotates forward and backward, a rotation direction detection unit that detects the rotation direction of the rotor according to the increase or decrease of the pattern number determined by the pattern conversion unit,
The continuous angle calculation unit accumulates a positive angle change amount when the rotation direction detection unit detects a normal rotation, and accumulates a negative angle change amount when a reverse rotation is detected. The motor control device according to claim 1.   The angular velocity calculation unit includes a time interval measurement unit that measures a time interval at which the combination of values of the rotational position signal changes, and divides the time interval measured by the time interval measurement unit by a reference angle to obtain a rotor per sample time. The motor control device according to claim 1, wherein an angle change amount of the motor is calculated.   The angular velocity calculation unit is a time interval from the rise of the value of the rotation position signal output by any one of the plurality of position detection units to the next rise for a brushless motor that continuously rotates in the same direction. Or a time interval measuring unit that measures a time interval from a falling to the next falling, and dividing the time interval measured by the time interval measuring unit by an electrical angle at which the rotor makes one rotation, The motor control device according to claim 1, wherein an angle change amount of the rotor is calculated. A stability evaluation unit that determines whether or not the rotational speed of the rotor is stable;
The amount of change in angle per sample time calculated by the angular velocity calculation unit is the period from the rise of the value of the rotational position signal output by one of the position detection units to the next rise or the fall A stable continuous angle calculation unit that calculates a continuous angle by accumulating every period sample time from the first to the next fall,
An output switching unit that switches to the continuous angle calculation unit at the time of stability when the stability evaluation unit determines to be stable, and switches to the continuous angle calculation unit when it is determined that the stability is not stable, The motor control device according to claim 5.   The motor control device according to claim 6, wherein the stability evaluation unit determines the stability based on a change amount per sample time of a time interval measured by the time interval measurement unit.   The angular velocity calculation unit includes an upper limit value of a time interval corresponding to the minimum rotation speed at which the brushless motor can be activated, and a time interval correction unit that limits the time interval measured by the time interval measurement unit to the upper limit value. 6. The motor control apparatus according to claim 4, wherein the motor control apparatus is characterized.

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