JP2013165575A - Motor drive apparatus and brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress noise resulting from a deviation of a magnetic sensor attachment position, an error in position detection, or the like.SOLUTION: A motor drive apparatus includes: a commutation timing generation part 47 for outputting a commutation timing signal Dp; a drive waveform generation part 42 for outputting a waveform signal Wd in accordance with a timing of the commutation timing signal Dp; and an inverter 44 that energizes a winding 16 on the basis of a drive pulse signal Pd that is pulse width modulated using the waveform signal Wd. When a rotation speed is in a change state, the commutation timing generation part 47 outputs the commutation timing signal Dp generated based on a sensor signal Ss for each phase at a first timing generation part and when the rotation speed is in a stationary state, the commutation timing generation part 47 outputs the commutation timing signal Dp generated based on a single sensor signal Ss at a second timing generation part.

Description

  The present invention relates to a motor drive device for a brushless motor used in a blower such as a fan motor or a blower, and a brushless motor including the motor drive device, and more particularly to a motor drive device and a brushless motor using a magnetic sensor.

  Such a brushless motor generally includes a magnetic sensor for detecting the rotational position of the rotor. Then, the stator winding is energized and driven at the commutation timing based on the rotational position information detected by the magnetic sensor, thereby controlling the rotational position and rotational speed of the rotor. However, for example, if the mounting position of the magnetic sensor is deviated, rotation unevenness or the like occurs, which causes an increase in rotational sound.

  For this reason, conventionally, a technique has been proposed in which the sensor signal from the magnetic sensor is corrected and the commutation timing is generated based on the corrected sensor signal, thereby suppressing the influence due to the deviation of the mounting position of the magnetic sensor. (For example, refer to Patent Document 1).

  On the other hand, there have been proposed technologies that do not use a magnetic sensor using an induced voltage, reduce the number of magnetic sensors, and reduce rotation unevenness. As an example of such a technique, a conventional commutation timing for switching excitation to each phase is generated for a three-phase brushless motor using position information by a magnetic sensor and an induced voltage, There is a brushless motor driving device that achieves rotation unevenness (see, for example, Patent Document 2).

  In the conventional technique such as Patent Document 2, uneven rotation is reduced by the following configuration. That is, first, the rotor magnetization information is read by a magnetic sensor to obtain rotor position information, and an induced voltage generated from the stator winding during rotation is detected. And a temporary commutation timing is set from the positional information by a magnetic sensor between starting of a motor and predetermined time. After a predetermined time, the position information obtained by the magnetic sensor is corrected with the position information obtained by detecting the induced voltage, and the commutation timing is set based on the corrected position information. With such a configuration, during steady operation after a predetermined time, rotation is controlled based on position information based on the induced voltage, so that rotation unevenness due to an error in the magnetization pattern is suppressed.

JP 2005-110363 A JP 2000-295890 A

  However, the conventional brushless motor driving apparatus as in Patent Document 1 corrects the position signal for each phase. For this reason, although the rotation accuracy is improved by the correction, the timing error of the sensor signal due to the mounting error of the magnetic sensor that is the basis of the position signal cannot be completely corrected to zero, so the rotation due to the residual timing error between the phases The fluctuation appears as sound, which may increase noise. In the case of a three-phase full-wave drive motor, the noise resulting from the timing error between the phases is a harmonic of the number of magnetic poles of the rotor, and is three times the number of magnetic poles of the rotor, which is the frequency of noise when there is no timing error between phases. Compared to the harmonics, many harmonics are generated, which is annoying noise. In particular, when a brushless motor is used in an in-vehicle blower, it is important to reduce noise because an air inlet and outlet are often set near the passenger.

  Further, in the conventional brushless motor driving apparatus as in Patent Document 2, it is necessary to detect the induced voltage, and there is a problem that if the induced voltage is not accurately detected, the detection error affects the rotation unevenness. Furthermore, to detect the induced voltage accurately, it is necessary to run the motor in a state in which the energization to the winding is stopped. When the energization is stopped in this way, there is a problem that distortion occurs in the energization waveform, and this distortion causes noise. In particular, in the technique as disclosed in Patent Document 2, it is necessary to stop energization during steady operation, and it is easy to be recognized as noise.

  The present invention has been made to solve such a problem, and a motor drive device that drives a motor so as to suppress noise based on a displacement of a magnetic sensor mounting position, an error in position detection, and the like, and the motor drive device It aims at providing a brushless motor provided with.

  In order to achieve the above object, a motor driving device according to the present invention is a motor driving device for driving a brushless motor including a rotor holding a permanent magnet and a stator wound with a winding for each phase. A commutation timing generation unit that generates and outputs a commutation timing signal indicating a commutation timing based on sensor signals of a plurality of magnetic sensors disposed opposite to the waveform sensor, and a waveform signal for driving the winding A drive waveform generation unit that generates and outputs a waveform signal according to the timing of the commutation timing signal, a PWM circuit that generates a drive pulse signal that is pulse-width modulated by the supplied waveform signal, and a winding based on the drive pulse signal And an inverter to be energized. Furthermore, the commutation timing generation unit generates a commutation timing signal based on a first timing generation unit that generates a commutation timing signal based on the sensor signal for each phase from the magnetic sensor, and a commutation timing based on one sensor signal from the magnetic sensor. And a second timing generation unit that generates a signal. The commutation timing generation unit outputs the commutation timing signal generated by the first timing generation unit when the rotation speed of the rotor is in a changing state, and the second timing when the rotation speed of the rotor is in a steady state. It is the structure which outputs the commutation timing signal produced | generated by the production | generation part.

  Further, the brushless motor of the present invention includes such a motor driving device.

  With this configuration, during a period when the rotation speed is changing, such as when the motor is started, the rotation can be accurately controlled by following the change in the number of rotations using a magnetic sensor corresponding to each phase. Further, during steady operation where the rotation speed is constant, rotation control is performed based on position information based on one magnetic sensor, so that generation of noise based on residual timing errors for each magnetic sensor can also be suppressed.

  According to the motor drive device and the brushless motor of the present invention, since the rotation control is adapted to change at the time of rotation speed or in a steady state, the motor drive device and the brushless motor that suppress noise based on the positional deviation or detection error of the magnetic sensor. Can provide.

The figure which shows the cross section of the brushless motor provided with the motor drive device in embodiment of this invention The figure which shows the inside of the motor case of the brushless motor provided with the motor drive device from the upper surface Block diagram showing the configuration of the motor drive device The block diagram which shows the structure of the commutation timing production | generation part of the motor drive device The block diagram which shows the other structural example of the commutation timing production | generation part of the motor drive device

  Hereinafter, a motor driving device and a brushless motor including the same according to an embodiment of the present invention will be described with reference to the drawings.

(Embodiment)
FIG. 1 is a view showing a cross section of a brushless motor 10 provided with a motor drive device according to an embodiment of the present invention. In the present embodiment, an example of an inner rotor type brushless motor in which a rotor is rotatably disposed on an inner peripheral side of a stator will be described. The brushless motor 10 of the present embodiment has a plurality of phases of windings, and each phase is driven by a pulse-width modulated (hereinafter referred to as PWM) signal to rotate.

  As shown in FIG. 1, the brushless motor 10 includes a stator 11, a rotor 12, a circuit board 13, and a motor case 14. The motor case 14 is formed of a sealed cylindrical metal, and the brushless motor 10 has a configuration in which the stator 11, the rotor 12, and the circuit board 13 are accommodated in the motor case 14. The motor case 14 includes a case main body 14a and a case lid 14b. The motor case 14 is substantially sealed by attaching the case lid 14b to the case main body 14a.

  In FIG. 1, the stator 11 is configured by winding a winding 16 for each phase around a stator core 15. In the present embodiment, an example will be described in which a winding 16 divided into three phases of a U phase, a V phase, and a W phase that are 120 degrees out of phase with each other is wound around the stator core 15. The stator iron core 15 has a plurality of salient poles protruding toward the inner peripheral side. Further, the outer peripheral side of the stator core 15 has a substantially cylindrical shape, and the outer periphery thereof is fixed to the case main body 14a.

  A rotor 12 is inserted inside the stator 11 via a gap. The rotor 12 holds a cylindrical permanent magnet 18 on the outer periphery of the rotor frame 17, and is disposed so as to be rotatable around a rotating shaft 20 supported by a bearing 19. That is, the front end surface of the salient pole of the stator core 15 and the outer peripheral surface of the permanent magnet 18 are arranged to face each other.

  Further, in the brushless motor 10, a circuit board 13 on which various circuit components 31 are mounted is built in a motor case 14. These circuit components 31 constitute a motor drive device for controlling and driving the motor. In addition, a magnetic sensor 38 such as a Hall element is mounted on the circuit board 13 in order to detect the rotational position of the rotor 12. A support member 21 is attached to the stator core 15, and the circuit board 13 is fixed in the motor case 14 via the support member 21. Ends of the U-phase, V-phase, and W-phase windings 16 are led out from the stator 11 as lead wires 16 a, and the lead wires 16 a are connected to the circuit board 13.

  To make such a configuration, first, the stator 11 is inserted into the case body 14a and fixed to the inner surface of the case body 14a, and then the rotor 12 and the circuit board 13 are housed in the case body 14a. By fixing the case lid 14b to the case main body 14a, the brushless motor 10 incorporating the magnetic sensor and the motor driving device is formed. The brushless motor 10 may have a configuration in which a motor driving device is integrated.

  FIG. 2 is a diagram showing the inside of the motor case 14 of the brushless motor 10 according to the present embodiment from the top. FIG. 2 shows the stator core 15 in a state where the winding 16 is not wound. FIG. 2 shows the positional relationship between the stator iron core 15, the permanent magnet 18, and the magnetic sensor 38 disposed on the lower surface of the permanent magnet 18.

  As shown in FIG. 2, the stator iron core 15 includes an annular yoke 15a and teeth 15b as salient poles. In the present embodiment, an example having twelve teeth 15b with 12 salient poles is given. The outer periphery of the stator iron core 15 is fixed to the inner surface of the case body 14a. Each of the teeth 15b extends and protrudes toward the inner peripheral side, and is disposed at equal intervals in the circumferential direction while forming slots that are spaces between the teeth 15b. The teeth 15b are sequentially associated with any one of the U phase, the V phase, and the W phase. A U-phase winding 16 is wound around the U-phase teeth 15b, a V-phase winding 16 is wound around the V-phase teeth 15b, and a W-phase winding is wound around the W-phase teeth 15b. 16 is wound.

  Further, the rotor 12 is disposed on the inner peripheral side facing the tip portions of the twelve teeth 15b. The permanent magnets 18 held by the rotor 12 are magnetized at equal intervals in the circumferential direction so that S poles and N poles are alternately arranged. As shown in FIG. 2, the permanent magnet 18 of the present embodiment is magnetized so that there are 5 pairs of S and N poles, that is, 10 poles in the circumferential direction. Thus, the brushless motor 10 has a configuration of 10 poles and 12 slots.

  Further, the circuit board 13 is disposed on the lower surface side of the permanent magnet 18, and three magnetic sensors 38 are mounted on the circuit board 13 so as to face the permanent magnet 18. As shown in FIG. 2, the magnetic sensor 38 includes a magnetic sensor 38U corresponding to the U-phase, a magnetic sensor 38V corresponding to the V-phase, and a magnetic sensor 38W corresponding to the W-phase, and is equally spaced in the circumferential direction. Has been placed.

  By supplying a power supply voltage and a control signal from the outside to the brushless motor 10 configured as described above, a drive current flows through the winding 16 by the control circuit and the drive circuit of the circuit board 13, and the stator core 15 Magnetic field is generated. The magnetic field from the stator iron core 15 and the magnetic field from the permanent magnet 18 generate an attractive force and a repulsive force according to the polarities of the magnetic fields, and the rotor 12 rotates around the rotating shaft 20 by these forces.

  Next, the motor drive device according to the present embodiment configured by the circuit components 31 mounted on the circuit board 13 will be described.

  FIG. 3 is a block diagram showing the configuration of the motor drive device 40 in the present embodiment.

  The motor drive device 40 includes a rotation control unit 41, a drive waveform generation unit 42, a PWM circuit 43, an inverter 44, a position detection unit 45, a speed calculation unit 46, and a commutation timing generation unit 47. The motor drive device 40 is notified of a speed command signal Vr that commands, for example, the number of rotations per minute (rpm) as the rotation speed, for example, from an external host device. Further, the motor drive device 40 is supplied with sensor signals Ss corresponding to the phases from the magnetic sensors 38U, 38V and 38W, respectively. In the motor drive device 40, the speed command signal Vr is notified to the rotation control unit 41 and the commutation timing generation unit 47. Further, the sensor signal Ss is supplied to the position detection unit 45.

  In the motor drive device 40, the position detection unit 45 detects the position information of each phase from the sensor signal Ss that changes according to the change in the magnetic pole accompanying the rotation of the rotor 12. For example, the position detection unit 45 detects the timing at which the sensor signal Ss crosses zero at the magnetic pole change time, and outputs the position detection signal Sp based on the detected timing. Specifically, the position detection signal Sp may be a pulse signal indicating such detection timing, for example. The position detection unit 45 supplies a position detection signal Sp corresponding to each phase to the speed calculation unit 46 and the commutation timing generation unit 47.

  The speed calculation unit 46 detects the rotational position of the rotor 12 based on the position detection signal Sp, and further calculates the rotational speed of the rotor 12 based on the detected rotational position by, for example, differential calculation. The speed calculation unit 46 supplies the calculated rotation speed to the rotation control unit 41 as the speed detection signal Vd.

  The rotation control unit 41 generates a rotation control signal Dd indicating a drive amount to the winding 16 based on the speed command signal Vr and the speed detection signal Vd. Specifically, the rotation control unit 41 obtains a speed deviation between the speed command signal Vr indicating the speed command and the speed detection signal Vd indicating the detected speed. And the rotation control part 41 produces | generates the rotation control signal Dd which shows the torque amount according to a speed deviation so that it may become actual speed according to a speed command. The rotation control unit 41 supplies such a rotation control signal Dd to the drive waveform generation unit 42.

  The drive waveform generator 42 generates a waveform signal Wd for driving the winding 16 for each phase, and supplies the generated waveform signal Wd to the PWM circuit 43. In this embodiment, a sine wave signal is used as the waveform signal Wd in order to suppress generation of unnecessary harmonic torque that becomes noise. And the timing which supplies the waveform signal Wd to the PWM circuit 43 is determined based on the commutation timing signal Dp from the commutation timing production | generation part 47 as a commutation timing. In this timing, basically, the U phase, the V phase, and the W phase are different in electrical angle by 120 degrees. Thus, the commutation control is performed by driving the windings 16 of each phase so that the energization is switched every 120 degrees. In addition, the timing of rotational position detection indicated by the position detection signal Sp is used as a reference timing. For example, when the advance angle control is performed, the timing indicated by the commutation timing signal Dp is a timing advanced by a predetermined phase from the reference timing. Further, if the mounting position of the magnetic sensor 38 is shifted, the reference timing is also shifted, which causes a detection position error and a commutation timing error, which causes rotation unevenness.

  A PWM (Pulse Width Modulation) circuit 43 performs pulse width modulation (PWM) on each of the waveform signals Wd supplied from the drive waveform generation unit 42 for each phase as a modulation signal. The PWM circuit 43 supplies the drive pulse signal Pd, which is a pulse train signal pulse-width-modulated with the waveform signal Wd as described above, to the inverter 44.

  The inverter 44 energizes the winding 16 for each phase based on the drive pulse signal Pd to drive the winding 16. The inverter 44 includes a switching element connected to the positive side of the power source and a switching element connected to the negative side for each of the U phase, the V phase, and the W phase. Further, the opposite power supply sides of both the positive electrode side and the negative electrode side are connected to each other, and this connection portion serves as a drive output end portion for driving the winding 16 from the inverter 44. The U-phase drive output end Uo is connected to the winding 16U, the V-phase drive output end Vo is connected to the winding 16V, and the W-phase drive output end Wo is connected to the winding 16W via the lead wire 16a. Connected. In each phase, when the switch element is turned on / off by the drive pulse signal Pd, a drive current flows from the drive output end to the winding 16 via the switch element that is turned on from the power source. Here, since the drive pulse signal Pd is a signal obtained by performing pulse width modulation on the waveform signal Wd, the respective windings 16 are energized with the drive current corresponding to the waveform signal Wd when the switch elements are turned on and off in this way. Is done.

  With the configuration as described above, a feedback control loop for controlling the rotational speed of the rotor 12 according to the speed command signal Vr is formed.

  Next, the detailed configuration and operation of the commutation timing generation unit 47 that generates the commutation timing signal Dp indicating the commutation timing will be described.

  FIG. 4 is a block diagram illustrating a configuration of the commutation timing generation unit 47 in the present embodiment.

  As shown in FIG. 4, the commutation timing generation unit 47 corresponds to the position detection signal Sp from the position detection unit 45, the position detection signal Spu corresponding to the U phase, the position detection signal Spv corresponding to the V phase, and the W phase. The detected position detection signal Spw is supplied. Further, a speed command signal Vr is notified from an external host device or the like. Further, the commutation timing generation unit 47 is supplied with a clock signal Ck for performing digital processing and the like.

  As shown in FIG. 4, the commutation timing generation unit 47 includes a first timing generation unit 51 and a second timing generation unit 52 in order to generate the commutation timing signal Dp. The first timing generation unit 51 generates the first commutation timing signal Dp using the position detection signals Spu, Spv, Spw based on the phase-specific sensor signals Ss from the magnetic sensors 38. The second timing generation unit 52 generates the second commutation timing signal Dp using the position detection signal Spu based on one sensor signal Ss from one magnetic sensor 38U.

  Further, the commutation timing generation unit 47 switches and outputs the commutation timing signal Dp generated by the first timing generation unit 51 and the commutation timing signal Dp generated by the second timing generation unit 52. , Selectors 53v and 53w are provided. A speed monitoring unit 57 is provided to perform switching control of the selectors 53v and 53w according to the speed command signal Vr. That is, the selection of signals by the selectors 53v and 53w is switched by the selection signal Sel from the speed monitoring unit 57.

  In the present embodiment, in order to correct the commutation timing, the first timing generation unit 51 includes a correction unit 51u corresponding to the U phase, a correction unit 51v corresponding to the V phase, and a correction corresponding to the W phase. The unit 51w is provided. Furthermore, the second timing generation unit 52 includes delay units 52v and 52w that generate signals that are approximately 120 degrees out of phase with the input signal. The commutation timing generation unit 47 sets a correction value to the correction units 51u, 51v, 51w and a delay value to the delay units 52v, 52w according to the speed command signal Vr, and a correction value. And a memory 56 that stores delay values.

  More specifically, the position detection signal Spu corresponding to the U phase is supplied to the correction unit 51u. The correction unit 51u corrects the timing indicated by the position detection signal Spu, and the corrected signal is output as the U-phase commutation timing signal Dpu and supplied to the delay unit 52v.

  The delay unit 52v shifts the signal corrected by the correcting unit 51u by a time amount corresponding to about 120 degrees in electrical angle. The signal shifted in time by the delay unit 52v is supplied to the delay unit 52w together with one input terminal of the selector 53v. The delay unit 52w further time-shifts the supplied signal by a delay amount corresponding to about 120 degrees in electrical angle. The signal shifted in time by the delay device 52w is supplied to one input terminal of the selector 53w.

  The position detection signal Spv corresponding to the V phase is supplied to the correction unit 51v. The correction unit 51v corrects the timing indicated by the position detection signal Spv, and the corrected signal is supplied to the other input terminal of the selector 53v. The position detection signal Spw corresponding to the W phase is supplied to the correction unit 51w. The correction unit 51w corrects the timing indicated by the position detection signal Spw, and the corrected signal is supplied to the other input terminal of the selector 53w.

  The selector 53v selects one of the output signals from the delay unit 52v and the correction unit 51v in accordance with the selection signal Sel, and outputs the selected signal as the V-phase commutation timing signal Dpv. The selector 53w selects one of the output signals from the delay unit 52w and the correction unit 51w according to the selection signal Sel, and outputs the selected signal as the W-phase commutation timing signal Dpw.

  In the configuration of the commutation timing generation unit 47 shown in FIG. 4, first, the memory 56 stores a correction value for correcting the timing based on the position detection signal Sp to a desired timing. For example, when the advance angle control is performed, this correction value is a value corresponding to the advance amount. Further, it may be a value that corrects a positional shift that occurs when the magnetic sensor 38 is mounted. Such a correction value is stored in the memory 56 in association with each phase and the rotational speed. Further, the memory 56 similarly stores delay values for setting the delay amounts of the delay units 52v and 52w. These correction values and the like are set, for example, in an adjustment process in manufacturing the brushless motor 10. By setting an advance value, a position deviation correction value, etc. for each individual brushless motor 10, variations in assembly such as the mounting position of the magnetic sensor 38 and variations in the magnetic characteristics of the permanent magnet 18, as well as the optimal advance angle for that individual. Can absorb the influence of the motor, etc., and enables optimal commutation control for each motor.

  The setting unit 55 reads the correction value and delay value corresponding to the rotation speed indicated by the speed command signal Vr from the memory 56, and sets the read correction values to the correction units 51u, 51v, and 51w as shift amounts corresponding to the rotation speed. Are set in the delay units 52v and 52w. The memory 56 may be configured to store only a correction value corresponding to a representative rotational speed and calculate a correction value or a phase value corresponding to the speed command signal Vr by interpolation calculation or the like.

  The correction unit 51u generates a signal whose phase is shifted by the correction value VCu from the setting unit 55 with respect to the U-phase reference timing indicated by the position detection signal Spu. The correction unit 51u outputs the generated signal as a commutation timing signal Dpu indicating the U-phase commutation timing. Thereby, the commutation timing signal Dpu indicating the timing corrected by the correction value VCu with respect to the reference timing is output. Here, for example, when the correction value VCu indicating the advance amount is used, the timing indicated by the commutation timing signal Dp is the timing advanced by the phase of the correction value VCu from the reference timing. That is, when the advance value is set as the correction value VCu, the commutation timing signal Dpu indicating the timing advanced by the correction value VCu with respect to the reference timing is output. Based on the timing of the commutation timing signal Dpu, the winding 16U is energized through the PWM circuit 43 and the inverter 44.

  Similarly, the correction unit 51v generates and outputs a signal whose phase is shifted by the correction value VCv from the setting unit 55 with respect to the V-phase reference timing indicated by the position detection signal Spv. The correction unit 51w generates and outputs a signal whose phase is shifted by the correction value VCw from the setting unit 55 with respect to the W-phase reference timing indicated by the position detection signal Spw.

  Further, the commutation timing signal Dpu output from the correction unit 51u is also supplied to the delay unit 52v. Further, the signal output from the delay unit 52v is supplied to the delay unit 52w. Here, the delay units 52v and 52w generate and output a signal indicating a timing delayed by a delay amount corresponding to a phase of about 120 degrees in electrical angle with respect to the timing indicated by the input signal. That is, with such a configuration, the delay unit 52v outputs a signal whose phase is shifted by about 120 degrees in electrical angle with respect to the timing indicated by the commutation timing signal Dpu, and the delay unit 52w outputs the commutation timing signal Dpu. Is output with a phase shifted by about 240 degrees in electrical angle. In the present embodiment, the delay units 52v and 52w are configured to generate signals whose phases are shifted by the delay values VPv and VPw from the setting unit 55. With this configuration, the phase difference of 120 degrees or 240 degrees is fine. Adjustment is possible. As a more specific configuration of the delay units 52v and 52w, a clock signal Ck is supplied to the delay units 52v and 52w, and the delay units 52v and 52w count the number of clocks according to the delay value. It is configured to delay by a desired phase amount.

  The selector 53v is supplied with the output signal of the correction unit 51v and the output signal of the delay unit 52v, and the selector 53v selects and outputs one of the output signals according to the selection signal Sel from the speed monitoring unit 57. The selector 53w is supplied with the output signal of the correction unit 51w and the output signal of the delay unit 52w. The selector 53w selects and outputs one of the output signals according to the selection signal Sel from the speed monitoring unit 57. To do.

  Based on the speed command signal Vr, the speed monitoring unit 57 detects whether the rotational speed of the rotor 12 is in a changing state or a steady state, and outputs the detected result to the selectors 53v and 53w as a selection signal Sel. In accordance with the selection signal Sel, the selector 53v selects the output signal of the correction unit 51v when the rotational speed is in a changing state, and selects the output signal of the delay device 52v when the rotational speed is in a steady state. Then, the selector 53v outputs the selected output signal as a commutation timing signal Dpv indicating the V-phase commutation timing. In addition, the selector 53w selects the output signal of the correction unit 51w when the rotational speed is in a changing state, and selects the output signal of the delay unit 52w when the rotational speed is in a steady state, according to the selection signal Sel. Then, the selector 53w outputs the selected output signal as a commutation timing signal Dpw indicating the W-phase commutation timing.

  As described above, the commutation timing generation unit 47 includes the first timing generation unit 51 that generates the commutation timing signal Dp and the magnetic sensor 38 based on the sensor signal Ss for each phase from the magnetic sensor 38. The second timing generation unit 52 generates a commutation timing signal Dp based on one sensor signal Ss. When the rotational speed of the rotor 12 is in the changing state, the commutation timing signal Dp generated by the first timing generating section 51 is output. When the rotational speed of the rotor 12 is in the steady state, the second timing generating section 52 is output. The commutation timing signal Dp generated in (1) is output. In the present embodiment, such a configuration enables commutation based on the sensor signal Ss for each phase when the rotational speed of the rotor 12 is changing, for example, when the brushless motor 10 is started or when the speed is changed. By driving the winding 16 at the timing, the rotation is accurately controlled by following the change in the number of rotations. On the other hand, the correction units 51u, 51v, and 51w cannot correct the commutation timing error to zero completely, and the timing error remains in the timing between the phases. For this reason, in the present embodiment, during the steady operation in which the rotational speed of the rotor 12 is constant, the winding 16 is driven at the commutation timing based on one sensor signal Ss, so that the residual timing error is suppressed to a lower level. Generation of noise based on the residual timing error for each magnetic sensor 38 is suppressed.

  The configuration of the commutation timing generation unit 47 has been described with reference to the configuration example illustrated in FIG. 4, but other modified configurations are possible.

  FIG. 5 is a diagram illustrating a configuration example in which the commutation timing generation unit 47 of FIG. 4 is modified. The commutation timing generation unit 471 shown in FIG. 5 has a U-phase configuration, and outputs any one of the delay unit 52u that shifts the electrical angle from 0 degree by a minute delay amount and the delay unit 52u and the correction unit 51u. The selector 53u for selecting a signal is further provided. Here, the position detection signal Spu is supplied to the delay device 52u, and the output signal of the delay device 52u is supplied to the delay device 52v. Even with the configuration as shown in FIG. 5, when the rotational speed is changing, the winding 16 is driven at a commutation timing based on the sensor signal Ss for each phase, so that the rotation is accurately controlled. Generation of noise can be suppressed by driving the winding 16 at the commutation timing based on the signal Ss. In addition to the configurations of FIGS. 4 and 5, for example, a modified configuration in which the position detection signal Spu is delayed by about 0 degrees, about 120 degrees, and about 240 degrees in parallel and supplied to the selector is possible. Further, the second timing may be generated by delaying the position detection signal Spv or the position detection signal Spw. In short, when the rotational speed of the rotor 12 is in the changing state, the winding 16 is driven for each phase at the commutation timing based on the sensor signal Ss for each phase, and when the rotational speed is in the steady state, one sensor signal Ss is obtained. What is necessary is just to set it as the structure which drives the coil | winding 16 for every phase with the commutation timing produced | generated based on it.

  In the above description, the configuration of the motor driving device 40 has been described using a block diagram of functional blocks. For example, a block for performing control and processing is configured by processing using a microcomputer (hereinafter referred to as a microcomputer). May be. That is, functions such as the rotation control unit 41, the drive waveform generation unit 42, the PWM circuit 43, the speed calculation unit 46, and the commutation timing generation unit 47 are set as programs stored in the memory 56, and the microcomputer reads and executes the programs. It is also possible to adopt such a configuration. Further, such a microcomputer may be mounted on the circuit board 13 as one of the circuit components 31 and the circuit board 13 may be built in the motor case 14 to form the brushless motor 10. In particular, by incorporating a program for setting a correction value for correcting the positional deviation in the correction units 51u, 51v, and 51w with respect to the positional deviation caused by mounting the magnetic sensor 38, the brushless motor 10 is provided. Completion of a single unit can generate correction values. A correction value can be set in advance for each brushless motor 10 in an adjustment process in manufacturing the brushless motor 10.

  As described above, the motor driving device according to the present invention generates a commutation timing signal indicating the commutation timing based on the sensor signals of a plurality of magnetic sensors arranged facing the permanent magnet and outputs the commutation timing signal. Current timing generation unit, a drive waveform generation unit that generates a waveform signal for driving the winding and outputs the waveform signal according to the timing of the commutation timing signal, and a drive pulse signal that is pulse-width modulated by the supplied waveform signal And an inverter for energizing the windings based on the drive pulse signal. Furthermore, the commutation timing generation unit generates a commutation timing signal based on a first timing generation unit that generates a commutation timing signal based on the sensor signal for each phase from the magnetic sensor, and a commutation timing based on one sensor signal from the magnetic sensor. And a second timing generation unit that generates a signal. The commutation timing generation unit outputs the commutation timing signal generated by the first timing generation unit when the rotation speed of the rotor is in a changing state, and the second timing when the rotation speed of the rotor is in a steady state. It is the structure which outputs the commutation timing signal produced | generated by the production | generation part.

  Further, the brushless motor of the present invention includes such a motor driving device.

  With this configuration, during a period when the rotation speed is changing, such as when the motor is started, the rotation can be accurately controlled by following the change in the number of rotations using a magnetic sensor corresponding to each phase. Further, during steady operation where the rotation speed is constant, rotation control is performed based on position information based on one magnetic sensor, so that generation of noise based on residual timing errors for each magnetic sensor can also be suppressed. Therefore, according to the present invention, since rotation control is adapted to change at the time of rotation speed or during steady state, it is possible to provide a motor drive device and a brushless motor in which noise based on positional deviation or detection error of the magnetic sensor is suppressed.

  The motor driving device and the brushless motor according to the present invention can suppress noise based on the displacement of the magnetic sensor mounting position or the error of position detection, so that low noise such as blowers such as fan motors and blowers, home appliances and electrical components This is useful for motor drive devices and brushless motors that require the

DESCRIPTION OF SYMBOLS 10 Brushless motor 11 Stator 12 Rotor 13 Circuit board 14 Motor case 14a Case main body 14b Case lid 15 Stator iron core 15a Yoke 15b Teeth 16, 16U, 16V, 16W Winding 16a Lead wire 17 Rotor frame 18 Permanent magnet 19 Bearing 20 Rotating shaft 21 Support member 31 Circuit component 38, 38U, 38V, 38W Magnetic sensor 40 Motor drive device 41 Rotation control unit 42 Drive waveform generation unit 43 PWM circuit 44 Inverter 45 Position detection unit 46 Speed calculation unit 47, 471 Commutation timing generation unit 51 First 1 timing generation unit 51u, 51v, 51w correction unit 52 second timing generation unit 52u, 52v, 52w delay unit 53u, 53v, 53w selector 55 setting unit 56 memory 57 speed monitoring unit

Claims (6)

A motor driving device for driving a brushless motor including a rotor holding a permanent magnet and a stator wound with a winding for each phase,
A commutation timing generation unit that generates and outputs a commutation timing signal indicating a commutation timing based on sensor signals of a plurality of magnetic sensors arranged to face the permanent magnet;
Generating a waveform signal for driving the winding, and outputting the waveform signal according to the timing of the commutation timing signal; and
A PWM circuit for generating a drive pulse signal that is pulse-width modulated by the supplied waveform signal;
An inverter for energizing the winding based on the drive pulse signal,
The commutation timing generation unit
A first timing generation unit that generates the commutation timing signal based on the sensor signal for each phase from the magnetic sensor;
A second timing generation unit that generates the commutation timing signal based on the one sensor signal from the magnetic sensor;
When the rotational speed of the rotor is in a change state, the commutation timing signal generated by the first timing generation unit is output,
A motor drive device that outputs a commutation timing signal generated by the second timing generation unit when the rotational speed of the rotor is in a steady state. The first timing generation unit corrects the timing based on the sensor signal for each phase according to a correction value set in advance for each motor, and generates a commutation timing signal indicating the corrected timing. The motor drive device according to claim 1. The second timing generator is
The signal timing based on the one sensor signal is time-shifted, and a signal indicating the time-shifted timing is generated,
The motor drive device according to claim 1, wherein a signal indicating the time shifted timing is used as a commutation timing signal together with a signal based on the one sensor signal. The commutation timing generation unit
A setting unit for setting a shift amount of the time shift;
The motor driving apparatus according to claim 3, wherein the setting unit sets a shift amount corresponding to the rotation speed in the second timing generation unit. The motor driving device according to claim 1, wherein the winding is driven with a driving waveform of a three-phase sine wave whose phase is different every 120 degrees in electrical angle. A brushless motor comprising the motor driving device according to any one of claims 1 to 5.

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