JP6206093B2 - Motor drive device and motor device - Google Patents

Description

  The present invention relates to a motor driving device and a motor device for driving a motor.

  In order to drive a brushless motor using a wide-angle wave such as a sine wave with low vibration, low noise, and high efficiency, it is necessary to match the phase of the motor driving current with the phase of the motor induced voltage. The phase of the motor drive current is delayed from the phase of the motor drive voltage. Therefore, considering the phase delay of the motor drive current with respect to the motor drive voltage, the phase of the motor drive voltage in accordance with the rotational speed command that instructs the motor drive speed so that the phase of the induced voltage and the phase of the motor drive current match. A technique has been proposed in which an advance value that is an advance angle is set and the phase of the motor drive voltage is advanced (see, for example, Patent Document 1).

JP 2008-154385 A

  However, if the motor drive current is suppressed by OCL (Current Limit Function: Over Current Limit) that controls the motor drive current within the set threshold, the motor rotation speed does not increase, and the difference between the rotation speed command and the actual motor rotation speed Will occur. When there is a difference between the rotational speed command and the actual motor rotational speed in this way, in the prior art, the advance value is fixed according to the rotational speed command of the motor, so the motor drive current and the induced voltage There is a problem that a phase shift occurs, resulting in an increase in vibration and noise, and a reduction in efficiency.

  In view of the above problems, the object of the present invention is to solve the problems of the prior art, and even if a difference occurs between the rotational speed command and the actual motor rotational speed, the phase difference between the induced voltage and the motor driving current is different. It is providing the motor drive device and motor apparatus which can suppress this.

The motor drive device of the present invention is a motor drive device that drives a brushless motor at a rotation speed based on a rotation speed command, and an advance value indicating a phase advance angle of a motor drive voltage applied to the brushless motor is set to the rotation speed. An advance value control unit that is set according to a command and corrects the advance value, a current limit unit that limits a motor drive current flowing through the brushless motor, and an advance angle corrected by the advance value control unit Waveform forming means for generating a drive waveform using a correction value, and inverter means for applying a motor drive voltage based on the drive waveform generated by the waveform forming means to the brushless motor, the advance value control It means the limit of the motor driving current by the current limiting means is started, to be smaller than the advance value of the advance correction value, the bra In synchronization with the motor rotation period of Resumota, and corrects the advance angle correction value stepwise to small angles.
The motor drive device of the present invention is a motor drive device that drives a brushless motor at a rotational speed based on a rotational speed command, and an advance value indicating a phase advance angle of a motor drive voltage applied to the brushless motor is described above. An advance value control means that is set according to a rotational speed command and corrects the advance value, a current limit means that limits a motor drive current that flows through the brushless motor, and is corrected by the advance value control means. Waveform forming means for generating a drive waveform using an advance angle correction value, and inverter means for applying a motor drive voltage based on the drive waveform generated by the waveform formation means to the brushless motor, the advance angle When the limit of the motor drive current by the current limiting unit is started, the value control unit makes the advance correction value smaller than the advance value, In a certain time period by mer, and corrects the advance angle correction value stepwise to small angles.

  According to the present invention, even if the motor drive current is suppressed and the motor rotation speed does not increase, and there is a difference between the rotation speed command and the actual motor rotation speed, the advance value is corrected according to the actual rotation speed. Therefore, the difference between the phase of the induced voltage and the phase of the motor drive current can be suppressed, and the brushless motor can be driven with low vibration, low noise, and high efficiency.

It is a circuit block diagram which shows the structure of embodiment of the motor drive device which concerns on this invention. It is a circuit block diagram which shows the structure of the 2nd waveform formation part shown in FIG. It is a figure which shows the conversion table of the rotational speed command which the advance value setting part shown in FIG. 2 has, and an advance value. It is a figure which shows the signal waveform and operation | movement waveform of each part of the motor drive device shown in FIG.

  Next, embodiments of the present invention will be specifically described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and a part of the description is omitted.

  The present embodiment is a motor drive device 1 that controls the drive of a brushless motor 3 based on a rotational speed command Vsp from a host device, and has an OCL (current limiting function) that controls a motor drive current within a set threshold as a protection function. : Over Current Limit). Referring to FIG. 1, the motor drive device 1 according to the present embodiment includes an inverter circuit 10, a motor driver 11, a current limiter 12, a position detector 13, a rotational speed detector 14, and an abnormality detector 15. A basic waveform forming unit 16, a first waveform forming unit 17, a second waveform forming unit 18, a drive switching determination unit 19, a protection stop unit 20, and a drive switching unit 21. Further, the position detection unit 13, the rotation speed detection unit 14, the abnormality detection unit 15, the basic waveform formation unit 16, the first waveform formation unit 17, the second waveform formation unit 18, and the drive switching determination unit 19 The protection stop unit 20 and the drive switching unit 21 constitute the motor controller 2. Furthermore, the motor drive device 1 and the brushless motor 3 constitute a motor device.

  The inverter circuit 10 is provided with a series circuit including a high-side arm and a low-side arm, each of which includes a parallel circuit in which a reflux diode is connected in reverse parallel to a switching element, corresponding to each of the U, V, and W phases. A motor drive voltage is output by performing on / off control of the switching element based on the output drive signal.

  The motor driver 11 converts the drive waveform output from the drive switching unit 21 into an optimal voltage and switching speed, and outputs the converted voltage to the inverter circuit 10 as a drive signal.

  The current limiting unit 12 detects a circuit current flowing through the inverter circuit 10 as a current detection value LS by a current detection resistor Rs provided on a grounded negative DC bus, and the current detection value LS is set to a preset OCL reference value. Is reached, the current limit signal OCL is output to the motor driver 11 and the second waveform forming unit 18. Then, the motor driver 11 to which the current limit signal OCL is input performs a protection operation for controlling the motor drive current within a set threshold. Further, the current limiting unit 12 outputs an overcurrent signal OCP to the abnormality detecting unit 15 when the current detection value LS reaches a preset OCP reference value. Then, the abnormality detection unit 15 to which the overcurrent signal OCP is input performs a protection operation for stopping the motor operation.

  The position detection unit 13 detects the rotation position of the rotor based on the Hall input signal from the Hall element 3a that detects the rotation position of the rotor of the brushless motor 3, and detects the rotation pulse FG as abnormal as the rotation speed detection unit 14. The data is output to the detection unit 15 and the second waveform forming unit 18.

  The rotation speed detection unit 14 calculates the motor rotation frequency (rotation speed) by measuring the period of the rotation pulse FG with a built-in counter, and outputs it to the abnormality detection unit 15 and the drive switching determination unit 19.

  The abnormality detection unit 15 detects a reverse rotation of the brushless motor 3 or an abnormally high rotation based on the abnormality of the position signal output from the position detection unit 13 or the motor rotation frequency output from the rotation speed detection unit 14. The overcurrent is detected by the overcurrent signal OCP output from the current control unit 12.

  The basic waveform forming unit 16 forms a triangular wave that is a basic waveform and outputs the triangular wave to the first waveform forming unit 17 and the second waveform forming unit 18.

  The first waveform forming unit 17 is based on the rotational speed command Vsp from the host device, the basic waveform output from the basic waveform forming unit 16, and the Hall input signal from the Hall element 3a. A drive waveform (rectangular wave drive (120 degrees)) is formed.

  The second waveform forming unit 18 outputs the rotation speed command Vsp from the host device, the basic waveform output from the basic waveform forming unit 16, the rotation pulse FG output from the position detection unit 13, and the current limiting unit 12. On the basis of the current limit signal OCL to be output and the drive method selection signal SE output from the drive switching determination unit 19, the drive waveform (wide angle wave drive such as a sine wave (150 degrees, 165 degrees) , 180 degrees etc.)).

  The drive switching determination unit 19 outputs a drive method selection signal SE for selecting a drive method to the drive switching unit 21 by comparing the motor rotation frequency calculated by the rotation speed detection unit 14 with a preset switching frequency. To do. Specifically, at the time of start-up / low-speed rotation where the motor rotation frequency is less than the switching frequency, the drive switching determination unit 19 drives to instruct selection of the driving waveform formed by the first waveform forming unit 17 that is the first driving method. The system selection signal SE is output to the drive switching unit 21 and instructed to select the drive waveform formed by the second waveform forming unit 18 that is the second drive system when the motor rotation frequency is at a medium speed or a high speed rotation greater than the switching frequency. The drive method selection signal SE to be output is output to the second waveform forming unit 18 and the drive switching unit 21.

  The protection stop unit 20 outputs a protection stop signal to the drive switching unit 21 when the abnormality detection unit 15 detects a position signal abnormality, reverse rotation or high rotation of the brushless motor 3, or overcurrent.

  The drive switching unit 21 outputs the drive waveform output to the motor driver 11 based on the drive method selection signal SE output from the drive switch determination unit 19 and the second drive waveform formed by the first waveform forming unit 17. The driving waveform is switched to one of the driving waveforms formed by the waveform forming unit 18. Further, when the protection stop signal is output from the protection stop unit 20, the drive switching unit 21 stops the output of the drive waveform.

  FIG. 2 shows an internal configuration of the second waveform forming unit 18. Referring to FIG. 2, the second waveform forming unit 18 includes a comparator 31, a PWM signal generating unit 32, an advance value setting unit 33, an advance value correcting unit 34, and a drive waveform forming unit 35. ing.

  The comparator 31 compares the rotational speed command Vsp input as a voltage value from the host device with the basic waveform (triangular wave) output from the basic waveform forming unit 16, and the PWM signal generating unit 32 Based on the comparison result, a PWM signal is generated and output to the drive waveform forming unit 35.

  The advance value setting unit 33 sets the advance value LA based on the rotation speed command Vsp, and outputs the set advance value LA to the advance value correction unit 34. As shown in FIG. 3, the advance value setting unit 33 has a correspondence table between the rotation speed command Vsp and the advance value LA, and sets the advance value LA according to the value of the rotation speed command Vsp. . In the present embodiment, the rotational speed command Vsp is set to 6 levels of “sp0” to “sp5”, and the advance value LA is also set to 6 levels of 0 to 5 like the rotational speed command Vsp. Has been. In the rotation speed command Vsp, “sp0” is a rotation stop command, and indicates a higher rotation speed as the number increases from “sp1”. In the advance value LA, “LA0” is 0 degree, and indicates a larger angle as the number increases from “LA1”.

  The advance value correction unit 34 includes a drive method selection signal SE output from the drive switching determination unit 19, a current limit signal OCL output from the current limit unit 12, and a rotation pulse FG output from the position detection unit 13. Based on the above, the advance value LA set by the advance value setting unit 33 is corrected, and the corrected advance value LA is output to the drive waveform forming unit 35 as an advance correction value LA ′. The advance value setting unit 33 and the advance value correction unit 34 may be configured separately, and as indicated by a broken line, they are a single advance having both an advance setting function and an advance correction function. The angle value control unit 36 may be configured.

  The drive waveform forming unit 35 includes a PWM signal output from the PWM signal generation unit 32, a rotation pulse FG output from the position detection unit 13, and an advance correction value LA ′ output from the advance value correction unit 34. Based on the above, a timing for energizing the brushless motor 3 is determined to form a drive waveform (wide angle wave such as a sine wave) during medium / high speed rotation.

  Next, the correction operation of the advance value LA by the advance value correction unit 34 will be described in detail with reference to FIG. 4 shows (a) rotation pulse FG, (b) rotation speed command Vsp, (c) advance angle value LA, (d) advance angle correction value LA ′, (e) current limit signal OCL, and (f) drive system. The waveform of the selection signal SE is shown.

  In the rotation stopped state, as shown in FIG. 4B, when “sp3” is input as the rotation speed command Vsp at time t1, the advance value setting unit 33, as shown in FIG. The advance value LA is set to “LA3” corresponding to “sp3” of the rotation speed command Vsp and output.

  As shown in FIG. 4 (f), at the time of startup, the drive switching determination unit 19 outputs a drive method selection signal SE for selecting the first drive method, and the drive waveform formed by the first waveform forming unit 17. As a result, the brushless motor 3 is driven. Then, when the drive method selection signal SE for selecting the first drive method is received from the drive switching determination unit 19, the advance value correction unit 34 sets the advance value as shown in FIG. Regardless of the advance value LA output from the unit 33, “LA0” is output as the advance correction value LA ′.

  As shown in FIG. 4 (f), when the motor rotation frequency reaches the switching frequency at time t2 and the driving method selection signal SE for selecting the second driving method is output from the driving switching determination unit 19, the advance value As shown in FIG. 4D, the correction unit 34 raises and outputs the advance correction value LA ′ by one step for every 60 degrees of electrical angle up to “LA3” set by the advance value setting unit 33. Thereby, the advance angle correction value LA ′ according to the actual rotational speed is set, and the deviation between the phase of the induced voltage and the phase of the motor drive current can be suppressed.

  Next, as shown in FIG. 4E, when the current limiting signal OCL is output from the current limiting unit 12 at time t3, the advance value correcting unit 34, as shown in FIG. The advance correction value LA ′ is pulled down by one step for every 60 degrees of electrical angle to “LA0” and output. As a result, the motor drive current is suppressed and the motor rotation speed does not increase, and even if there is a difference between the rotation speed command Vsp and the actual motor rotation speed, an advance correction value LA ′ suitable for the actual rotation speed is set. Thus, the deviation between the phase of the induced voltage and the phase of the motor driving current can be suppressed.

  Next, as shown in FIG. 4 (e), when the current limiting signal OCL from the current limiting unit 12 is turned off at time t4, the advance value correcting unit 34, as shown in FIG. 4 (d), The advance angle correction value LA ′ is pulled up by one step for every 60 degrees of electrical angle to “LA3” set by the advance angle value setting unit 33 and output. As a result, the advance angle correction value LA ′ corresponding to the actual rotational speed is set as the motor rotational speed increases due to the release of the suppression of the motor drive current, and the difference between the phase of the induced voltage and the phase of the motor drive current is set. Can be suppressed.

  In the present embodiment, when the current limiting signal OCL is output from the current limiting unit 12, the advance correction value LA ′ is set to “LA0” regardless of the advance value LA set by the advance value setting unit 33. However, it is also possible to set a correction limit value for the advance value LA set by the advance value setting unit 33. For example, when “−2” is set as the correction limit value, when the current limit signal OCL is output from the current limit unit 12, the advance value correction unit 34 sets “LA3” set by the advance value setting unit 33. The advance angle correction value LA ′ is lowered and outputted by one step every 60 degrees of electrical angle to “LA1” which is two steps lower than “LA1”.

  Further, the correction limit value may be set by changing according to operating conditions such as the rotational speed command Vsp. For example, the setting range of the rotation speed command Vsp is divided into several stages. The correction limit value is “−3” during high rotation, the correction limit value is “−2” during medium rotation, and the correction limit value is “ -1 "may be set. By setting the correction limit value in this way, it is possible to prevent synchronization deviation (step-out) between the motor rotor and the drive signal.

  Further, in the present embodiment, the advance angle correction value LA ′ is corrected one step at a time, but the advance angle correction value LA ′ may be corrected in a plurality of steps. In addition, the number of steps to be corrected by the advance correction value LA ′ may be switched and set. For example, when importance is attached to the stability, the number of steps to be corrected by the advance angle correction value LA ′ is set to “1”, and when importance is attached to the followability, the number of steps to be corrected by the advance angle correction value LA ′. May be set in multiple stages such as “2”. By correcting the advance angle correction value LA 'in multiple stages, it is possible to cope with significant speed fluctuations, and low vibration and low noise during motor rotation acceleration / deceleration (when the rotation speed command Vsp setting is changed) are expected. it can.

  In the present embodiment, the advance angle correction value LA ′ is corrected every 60 degrees of electrical angle in synchronization with the motor rotation cycle (rotation pulse FG) of the brushless motor 3. As described above, when the correction cycle is the motor rotation cycle, the followability of the advance angle correction is different between the low rotation time and the high rotation time. However, since it is synchronized with the motor rotation cycle, stable operation can be expected. Note that the correction cycle of the advance angle correction value LA ′ is not limited to the electrical angle of 60 degrees, and may be another angle. Furthermore, the correction cycle of the advance angle correction value LA ′ may be a fixed time cycle by a timer. In this case, the dependency on the motor rotation speed is eliminated, and improvement in the follow-up performance with respect to the rotation speed command Vsp can be expected.

As described above, the present embodiment is a motor drive device 1 that drives the brushless motor 3 at a rotational speed based on the rotational speed command Vsp, and shows the phase advance angle of the motor drive voltage applied to the brushless motor 3. An advance value control unit 36 (advance value setting unit 33, advance value correction) that sets an advance value LA according to the rotational speed command Vsp and outputs an advance value LA ′ obtained by correcting the advance value LA. Unit 34), a current limiting unit 12 that outputs a current limiting signal OCL that limits the motor driving current flowing through the brushless motor 3, and an advance angle correction value LA ′ output from the advance angle correction unit 34. A drive waveform forming unit 35 for generating the motor, and an inverter circuit 10 for applying a motor drive voltage based on the drive waveform generated by the drive waveform forming unit 35 to the brushless motor 3, and an advance value control unit 6 (advance angle correction unit 34), when the current limit signal OCL from the current limiting unit 12 is output, is configured to be smaller than the advance value LA of the advance angle correction value LA '.
With this configuration, the motor drive current is suppressed and the motor rotation speed does not increase, and even if there is a difference between the rotation speed command Vsp and the actual motor rotation speed, the advance correction value LA ′ corresponding to the actual rotation speed is set. The deviation between the phase of the induced voltage and the phase of the motor drive current can be suppressed, the brushless motor 3 can be driven with low vibration, low noise, and high efficiency, and low vibration, low noise, high An efficient motor device can be provided.

Furthermore, according to the present embodiment, the advance value control unit 36 (advance value correction unit 34) synchronizes with the motor rotation cycle of the brushless motor 3, and advances the advance correction value LA ′ in a stepwise small angle. It is comprised so that it may correct | amend.
With this configuration, since it is synchronized with the motor rotation period, stable operation can be expected.

Furthermore, according to the present embodiment, the advance value control unit 36 (advance value correction unit 34) corrects the advance angle correction value LA ′ to a small angle step by step in a constant time period by a timer. It is configured.
With this configuration, there is no dependency on the motor rotation speed, and an improvement in the follow-up performance with respect to the rotation speed command Vsp can be expected.

Furthermore, according to the present embodiment, a correction limit value for the advance value LA is set in the advance value control unit 36 (advance value correction unit 34). Furthermore, according to the present embodiment, the correction limit value is set so as to vary depending on the operating conditions.
With this configuration, it is possible to prevent synchronization deviation (step-out) between the motor rotor and the drive signal.

  Note that the present invention is not limited to the above-described embodiments, and it is obvious that the embodiments can be appropriately changed within the scope of the technical idea of the present invention. In addition, the number, position, shape, and the like of the constituent members are not limited to the above-described embodiment, and can be set to a suitable number, position, shape, and the like in practicing the present invention. In each figure, the same numerals are given to the same component.

DESCRIPTION OF SYMBOLS 1 Motor drive device 2 Motor controller 3 Brushless motor 3a Hall element 10 Inverter circuit 11 Motor driver 12 Current limiting part 13 Position detection part 14 Rotation speed detection part 15 Abnormality detection part 16 Basic waveform formation part 17 1st waveform formation part 18 2nd Waveform formation unit 19 Drive switching determination unit 20 Protection stop unit 21 Drive switching unit 31 Comparator 32 PWM signal generation unit 33 Advance value setting unit 34 Advance value correction unit 35 Drive waveform formation unit 36 Advance value control unit

Claims (5)

A motor driving device that drives a brushless motor at a rotational speed based on a rotational speed command,
An advance value control means for setting an advance value indicating a phase advance angle of a motor drive voltage applied to the brushless motor in accordance with the rotation speed command and correcting the advance value;
Current limiting means for limiting the motor drive current flowing through the brushless motor;
Waveform forming means for generating a drive waveform using the advance correction value corrected by the advance value control means;
Inverter means for applying a motor drive voltage based on the drive waveform generated by the waveform forming means to the brushless motor;
The advance value control means makes the advance angle correction value smaller than the advance angle value and synchronizes with the motor rotation period of the brushless motor when the motor drive current restriction by the current restriction means is started. The motor drive device is characterized in that the advance angle correction value is corrected to a small angle step by step . A motor driving device that drives a brushless motor at a rotational speed based on a rotational speed command,
An advance value control means for setting an advance value indicating a phase advance angle of a motor drive voltage applied to the brushless motor in accordance with the rotation speed command and correcting the advance value;
Current limiting means for limiting the motor drive current flowing through the brushless motor;
Waveform forming means for generating a drive waveform using the advance correction value corrected by the advance value control means;
Inverter means for applying a motor drive voltage based on the drive waveform generated by the waveform forming means to the brushless motor;
The advance angle control means makes the advance angle correction value smaller than the advance angle value when the limit of the motor drive current by the current limit means is started, and makes the advance angle at a constant time period by a timer. A motor driving device that corrects a correction value to a small angle step by step . 3. The motor driving apparatus according to claim 1, wherein a correction limit value for the advance value is set in the advance value control means. 4. The motor driving apparatus according to claim 3 , wherein the correction limit value is set so as to vary depending on operating conditions. A motor driving device according to any one of claims 1 to 4, a motor apparatus characterized by comprising a brushless motor, the applied motor driving voltage from the motor driving device.

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