JP2008054370A - Motor driving apparatus and motor driving method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the noise and vibration of a motor at reversal brake control by delaying the phase of current waves applied to a motor coil at reversal brake control. <P>SOLUTION: A position detector 2 has a rotor position detection signal from a sensor 1 inputted, and generates a position detection signal P0 whose phase is in accord with the phase of the induced voltage of the motor 9, and inputs it into a phase controller 10. The phase controller 10 generates a phase signal P1 whose phase is shifted from that of the inputted position detection signal P0, and outputs it, according to a rotational signal switching signal FR. A current application controller 3 receives the output from the phase controller 10, and generates a current application switching signal (motor drive signal) for determining the timing of applying the current to each phase of the motor coil, and a motor drive 4 supplies the motor 9 with a current, according to the current application switching signal. At reversal brake control, it delays the phase of current application of the motor coil, using the phase signal P1, whereby it suppresses the distortion of current waves caused by the influence of the induced voltage of the motor 9 thereby reducing the noise and vibration. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a device for driving a motor, and more particularly to a motor driving device and a motor driving method for reducing noise during brake control.

  In recording devices such as magnetism, light, and magneto-optical, multiphase DC brushless motors that are excellent in high reliability and high speed are widely used. In general, this multi-phase DC brushless motor rotates by sequentially switching the current flowing through each phase motor coil based on rotor position information from an induced voltage generated by the rotation of the position detection element and the motor.

  In addition, a reverse rotation brake that applies a torque in the reverse rotation direction from rotor position information during brake control, a short brake that short-circuits all terminals of the multiphase DC brushless motor, and the like are widely used.

  In recent recording devices, recording density has been improved and video and audio recording applications have been expanded. Therefore, not only when a multiphase DC brushless motor is started or at a constant rotation, but also noise and vibration during brake control can be reduced. It is becoming important.

  The causes of noise and vibration during motor reverse rotation brake control will be described below. FIG. 7 is a block diagram of a conventional motor driving apparatus. In FIG. 7, 1 is a position detection element (hereinafter referred to as a sensor), 2 is a position detection unit, 3 is an energization control unit, 4 is a motor drive unit, 5 is a motor current detection unit, 6 is a PWM control unit, and 7 is a torque. A command value signal, 8 is a rotation direction switching unit, and 9 is a DC brushless motor (hereinafter referred to as a motor).

  FIG. 8 is a block diagram showing the aforementioned PWM control unit. In FIG. 8, 61 is a comparator, 62 is an oscillator for generating a clock pulse which is a PWM reference signal, and 63 is a flip-flop circuit. FIG. 9 is a block diagram showing the rotation direction switching unit. In FIG. 9, 7 is a torque command value signal, 81 is a comparator, and 82 is a reference voltage VREF.

  As shown in FIG. 7, the sensor 1 detects the rotor position of the motor 9 and outputs a detection signal corresponding to the rotor position to the position detector 2. The position detection unit 2 calculates a rotor position detection signal and outputs a position detection signal P0 for determining the energization phase to the motor 9 to the energization control unit 3. The output of the energization control unit 3 is input to the motor drive unit 4 and energized to the motor 9. The motor current detector 5 detects the current flowing through the motor 9 and inputs it to the PWM controller 6. The PWM control unit 6 receives the motor current detection signal Vcs detected by the motor current detection unit 5 and the torque command value signal 7, and the motor current detection signal Vcs is output by the comparator 61 as shown in FIG. When the value signal 7 is reached, a reset pulse signal res is output. The oscillator 62 periodically outputs a set pulse signal set that starts energization, which is a PWM reference signal. The flip-flop circuit 63 receives the set pulse signal set and the reset pulse signal res described above, and generates a PWM control signal pwm. As shown in FIG. 9, the rotation direction switching unit 8 outputs a rotation direction switching signal FR that determines the rotation direction according to the comparison result between the torque command value signal 7 and the reference voltage VREF and inputs the rotation direction switching signal FR to the energization control unit 3. .

  FIG. 10 is a diagram showing the phase relationship between the induced voltage Bemf and the current waveform applied to the motor coil during forward rotation control and reverse rotation control (reverse rotation brake control). In FIG. 10, the section of θ1 to θ2 is forward rotation control, and the section of θ2 to θ4 is reverse rotation brake control. During forward rotation control, energization is performed so that the phase of the current matches the induced voltage Bemf. On the other hand, at the time of reverse rotation brake control, energization is performed so that the phase of the current is inverted by 180 degrees with respect to the induced voltage Bemf to obtain brake torque. The induced voltage Bemf generated during motor rotation acts in a direction in which current does not easily flow through the motor coil during forward rotation control, but the current flowing direction is shifted by 180 degrees during reverse rotation brake control, thus acting in a direction in which current flows easily through the motor coil. To do.

  Therefore, the motor coil current immediately reaches the torque command value signal 7 during reverse rotation brake control. However, the PWM control unit 6 has a current detection prohibition period in order to prevent erroneous detection of the motor current detection unit 5, and during this current detection prohibition period, the motor current value signal Vcs reaches the torque command value signal 7 and is reset. Even when the pulse signal res is generated, the reset pulse signal res is invalidated. As a result, a current exceeding the torque command value flows, and the current waveform is distorted. In particular, the current in the vicinity of the switching of the energization direction (the timings θ3 and θ4 in FIG. 10) is large, and when the energization direction is switched, a steep current change occurs, causing noise and vibration.

  In order to solve these problems, for example, in Patent Document 1, when a signal for switching to low-speed rotation is input from an external unit, a drive stop control unit that stops energization of the motor until a predetermined condition is satisfied. By taking it, noise and vibration are suppressed.

In Patent Document 2, when a forward / reverse command signal is a reverse command and a brake command is input, a rotation frequency signal proportional to the rotation speed of the rotor is compared with a reference frequency. In addition, when the signal is lower than the reference signal, the occurrence of noise and vibration is suppressed by taking means for setting the reverse rotation brake state.
JP-A-11-136993 JP 2001-309686 A

  However, in the method described in Patent Document 1, although noise and vibration can be reduced, there is a problem in that since the energization is stopped for a predetermined time, the brake torque does not work and the access speed at the time of recording or reading becomes slow. This is fatal in recording devices such as magnetism, light, and magneto-optical.

  Further, in the method described in Patent Document 2, noise and vibration are generated when the short brake is switched to the reverse rotation brake if the reference frequency is set too high, and the brake time is delayed if the reference frequency is set too low. There was a problem.

  The present invention is directed to solving the problems of the prior art, and during reverse rotation brake control, the phase of the current waveform applied to the motor coil is delayed to cause distortion of the current waveform caused by the influence of the induced voltage of the motor. An object of the present invention is to provide a motor drive device and a motor drive method that can suppress noise and reduce motor noise and vibration during reverse rotation brake control.

  In order to achieve the above object, a motor driving apparatus according to claim 1 of the present invention includes a position detection unit that detects a rotor position of a motor to be driven and generates a position detection signal, a torque command value, and a reference Depending on the voltage comparison result, a rotation direction switching unit that outputs a rotation direction switching signal for determining whether the rotation direction is forward rotation or reverse rotation, a position detection signal and a rotation direction switching signal are input, and the rotation direction switching signal is input. A phase control unit that outputs a phase signal obtained by shifting the phase of the position detection signal, a motor current detection unit that detects a motor current value flowing through the motor, and a torque command value and the motor current value are compared to generate a PWM signal. A PWM control unit; an energization control unit that inputs a rotation direction switching signal, a phase signal, and a PWM signal to generate a motor drive signal; and a motor drive unit that PWM-drives the motor according to the motor drive signal Characterized by comprising.

  The motor driving device according to claim 2 is the motor driving device according to claim 1, wherein the phase control unit has a predetermined amount within an electric angle range of 0 to 90 ° with respect to the position detection signal. The phase control unit outputs a phase signal whose phase is shifted, and the phase control unit outputs a phase signal in phase with the induced voltage of the motor during forward rotation control, and an electrical angle of 0 to 90 from the induced voltage of the motor during reverse rotation control. A phase signal delayed by a predetermined amount within a range of ° is output.

  According to a fourth aspect of the present invention, the motor driving method detects the rotor position of the motor to be driven and generates a position detection signal, and the rotation direction is positively rotated according to the comparison result between the torque command value and the reference voltage. A step of generating a rotation direction switching signal for determining whether to rotate or reverse rotation, a step of generating a phase signal obtained by shifting the phase of the position detection signal from the position detection signal and the rotation direction switching signal, and a motor current value flowing through the motor is detected. A step of generating a PWM signal by comparing a torque command value and a motor current value, a step of generating a motor drive signal by inputting a rotation direction switching signal, a phase signal and a PWM signal, and a motor drive signal And a step of PWM driving the motor accordingly.

  Further, the motor driving method according to claims 5 and 6 is the motor driving method according to claim 4, wherein the step of generating the phase signal is within an electric angle range of 0 to 90 ° with respect to the position detection signal. In the step of generating a phase signal whose phase is shifted by a predetermined amount, and in the step of generating the phase signal, a phase signal in phase with the induced voltage of the motor is generated during forward rotation control, and the induced voltage of the motor is controlled during reverse rotation control. A phase signal delayed by a predetermined amount within an electric angle range of 0 to 90 ° is generated.

  According to the apparatus and method of the said structure, by delaying an energization phase at the time of reverse rotation control, the distortion of the current waveform produced by the influence of the induced voltage of a motor can be suppressed, and the noise and vibration of the motor at the time of reverse rotation control can be reduced.

  According to the present invention, the phase applied to the motor coil during the reverse rotation brake control is delayed to suppress the distortion of the current waveform caused by the influence of the induced voltage of the motor, and the noise generated during the reverse rotation brake control in the multiphase DC brushless motor. , It is possible to reduce the vibration.

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

  FIG. 1 is a block diagram showing a schematic configuration of a motor drive device according to an embodiment of the present invention. Here, components having the same functions corresponding to the components described in FIG. 7 showing the conventional example are given the same reference numerals, and in this embodiment, a three-phase DC brushless motor is taken as an example. However, other types of motors may be used.

  As shown in FIG. 1, the motor drive device includes a position detection element (hereinafter referred to as a sensor) 1, a position detection unit 2, an energization control unit 3, a motor drive unit 4, a motor current detection unit 5, and PWM control. The unit 6 includes a torque command value signal 7, a rotation direction switching unit 8, a DC brushless motor (hereinafter referred to as a motor) 9, and a phase control unit 10.

  The sensor 1 is an element that outputs a signal corresponding to the rotor position of the motor 9, and is constituted by a Hall element, for example. In the present embodiment, the case where there are three sensors 1 is described as an example. However, one sensor 1 may be used. Further, the position detection method may be a method using an induced voltage generated in the motor coil without using a sensor.

  The operation of the motor drive device in this embodiment will be described. The sensor 1 outputs a detection signal corresponding to the position of the rotor of the motor 9. The rotor position detection signal from the sensor 1 is a signal delayed by 30 ° in the phase and electrical angle of the induced voltage of the motor 9.

  The rotor position detection signal is input to the position detection unit 2. The position detection unit 2 generates a position detection signal P 0 that matches the phase of the induced voltage of the motor 9 and inputs it to the phase control unit 10. The phase control unit 10 receives the position detection signal P0 and the rotation direction switching signal FR, and generates and outputs a phase signal P1 obtained by shifting the phases of the position detection signal P0 by a predetermined amount. Detailed operation of the phase control unit 10 will be described later.

  The energization control unit 3 receives the phase signal P1 from the phase control unit 10 and generates an energization switching signal (motor drive signal) that determines the timing of energizing the current for each phase of the motor coil. The motor drive unit 4 supplies current to the motor 9 in response to the energization switching signal.

  FIG. 2 is a diagram showing the phase relationship between the induced voltage Bemf of the motor, the position detection signal P0, and the current waveform supplied to the motor coil when the phase is not shifted in the phase control unit. The position detection signal P0 is a signal synchronized with the phase of the induced voltage Bemf of the motor 9, the signal level changes every 180 ° electrical angle, and the period from the rising edge to the next rising edge becomes an electrical angle of 360 °. . The motor 9 is energized according to the phase of the position detection signal P0.

  The motor current detector 5 detects the current flowing through the motor 9 and outputs a motor current value signal Vcs. The PWM controller 6 receives the motor current value signal Vcs detected by the motor current detector 5 and the torque command value signal 7 and outputs a PWM control signal pwm. Specifically, as shown in FIG. 8, in the PWM controller 6, the comparator 61 outputs a reset pulse signal res when the motor current value signal Vcs reaches the torque command value signal 7. The oscillator 62 periodically outputs a set pulse signal set which is a PWM reference signal for starting energization. The flip-flop circuit 63 receives the set pulse signal set and the reset pulse signal res described above, and generates a PWM control signal pwm. By synthesizing the PWM control signal pwm with the energization control unit 3, it is possible to intermittently energize a predetermined phase to rotate the motor 9 with low consumption and high efficiency. As described above, the motor current corresponding to the torque command value signal 7 can be obtained.

  Next, a detailed operation of the phase control unit 10 will be described. As described above, the phase control unit 10 receives the position detection signal P0 and the rotation direction switching signal FR, and outputs the phase signal P1 obtained by shifting the phase of the position detection signal P0 by a predetermined amount.

  FIG. 3 shows a configuration example of the phase control unit 10. As shown in FIG. 3, the phase control unit 10 includes counters 101, 103, 104, a holding circuit 102, an oscillator 105, a shift amount determination unit 106, and a switch circuit 107.

  The oscillator 105 outputs clock signals CK1 and CK2. The position detection signal P0 is a signal in phase with the induced voltage of the motor 9. The timing when the phase signal P1 is generated in the above configuration is as shown in FIG.

  The manner in which the phase signal P1 is generated will be described with reference to FIG. FIG. 4 shows the motor induced voltage Bemf, the position detection signal P0, the count data cnt1 of the counter 101, the holding data cdata of the holding circuit 102, the count data cnt2 of the counter 103, and the holding data cdata, and the divided signal D at “0”. And a timing chart showing each of the phase signal P1. Note that t1 and t2 are timings of rising edges of the position detection signal P0.

  The position detection signal P0 and the clock signal CK1 output from the oscillator 105 are input to the counter 101. The counter 101 counts the clock signal CK1 from the timing t1 of the first rising edge of the position detection signal P0 to the timing t2 of the second rising edge, and outputs the count result as count data cnt1.

  In the example illustrated in FIG. 4, the count data cnt1 is “10”. The counter 101 outputs count data cnt1 to the holding circuit 102. The holding circuit 102 holds the count data of the counter 101 at the edge timings t1 and t2 of the position detection signal P0. The held data cdata output from the holding circuit 102 and the clock signal CK 2 output from the oscillator 105 are input to the counter 103. The counter 103 counts down the held data cdata with the clock signal CK2, and outputs the divided signal D at the timing when it becomes “0”.

  In the example shown in FIG. 4, the holding data cdata is “10”, the counter 103 starts counting down from “10”, and outputs the division signal D when it reaches “0”. This divided signal D is a signal output for each predetermined electrical angle based on the period of the rotor electrical angle of 360 °. Here, the predetermined electrical angle can be determined by the ratio of the clock signal CK1 and the clock signal CK2 input to the counters 101 and 103, and can be set to an arbitrary electrical angle by appropriately changing the ratio. For example, in the present embodiment, the ratio of the clock signal CK1 to the clock signal CK2 is set to 1:12, so that the divided signal D is output every 30 electrical degrees.

  Next, operations of the counter 104 and the shift amount determination unit 106 will be described with reference to FIG. The counter 104 receives the divided signal D as a clock, performs a count at each timing when the divided signal D is input (every electrical angle 30 °), and resets the counter data cnt3 at the timing of the rising edge of the position detection signal P0. . The count data cnt3 output from the counter 104 is input to the shift amount determination unit 106. The shift amount determination unit 106 generates a phase signal P1 obtained by shifting the phase of the position detection signal P0 by a predetermined amount within the range of electrical angle 0 to 90 °. In the present embodiment, a signal shifted by 30 ° in electrical angle is generated. The phase signal P1 is a signal that is fixed to “High” when the count data cnt3 becomes “1” and is fixed to “Low” at the timing “7”.

  The position detection signal P0, the phase signal P1, and the rotation direction switching signal FR are input to the switch circuit 107, and the switch circuit 107 switches the output according to the value of the rotation direction switching signal FR. That is, when the rotation direction switching signal FR input to the switch circuit 107 is the first value (forward rotation), the position detection signal P0 that matches the phase of the induced voltage Bemf is output, and the second value (reverse rotation). In this case, a phase signal P1 obtained by shifting the phase of the divided signal D by a predetermined pulse from the phase of the induced voltage Bemf is output.

  With the above configuration, the phase signal P1 is switched according to the value of the rotation direction switching signal FR, and the phase of the phase signal P1 is shifted by an arbitrary pulse of the divided signal D from the phase of the induced voltage Bemf. In this embodiment, the divided signal D is output at every electrical angle of 30 °, and the phase signal P1 has a phase delayed by an electrical angle of 30 ° with respect to the phase of the induced voltage Bemf of the motor 9.

  FIG. 6 is a diagram showing a phase relationship between the induced voltage Bemf and the phase signal P1 of the motor according to the present embodiment, and the current waveform supplied to the motor coil when the phase is shifted in the phase control unit. As shown in FIG. 6, the phase of the current waveform that is energized is shifted by an electrical angle of 30 ° with respect to the phase of the induced voltage Bemf.

  As described above, according to the present embodiment, the current waveform distortion caused by the induced voltage of the motor 9 is suppressed and the reverse rotation is performed by delaying the energization phase of the current waveform energized to the motor coil during the reverse rotation brake control. It is possible to reduce motor noise and vibration during brake control.

  The motor drive device and motor drive method according to the present invention delays the phase of energizing the motor coil during reverse rotation brake control, suppresses distortion of the current waveform caused by the influence of the induced voltage of the motor, and controls the reverse rotation brake of the motor. It is possible to reduce the generated noise and vibration and is useful as a device for driving a motor.

The block diagram which shows schematic structure of the motor drive device in embodiment of this invention. The figure which shows the phase relationship between the induced voltage Bemf of a motor, the position detection signal P0, and the current waveform which supplies with electricity to a motor coil. Block diagram showing schematic configuration of phase controller Timing chart of motor induced voltage Bemf, position detection signal P0, count data cnt1, holding data cdata, count data cnt2 (divided signal D), and phase signal P1 Timing chart of position detection signal P0, division signal D (count data cnt2), count data cnt3, and phase signal P1 The figure which shows the phase relationship of the induced voltage Bemf of a motor, the phase signal P1, and the current waveform which supplies with electricity to a motor coil. Block diagram showing a schematic configuration of a conventional motor drive device Block diagram showing schematic configuration of PWM controller Block diagram showing the schematic configuration of the rotation direction switching unit The figure which shows the phase relationship between the induced voltage Bemf at the time of forward rotation control and reverse rotation brake control, and the electric current waveform supplied with a motor coil

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sensor 2 Position detection part 3 Current supply control part 4 Motor drive part 5 Motor current detection part 6 PWM control part 7 Torque command value signal 8 Rotation direction switching part 9 Motor 10 Phase control part 61, 81 Comparator 62, 105 Oscillator 63 Flip-flop Circuit 82 Reference voltage VREF
101, 103, 104 Counter 102 Holding circuit 106 Shift amount determination unit 107 Switch circuit

Claims (6)

  A position detection unit that detects the rotor position of the motor to be driven and generates a position detection signal, and a rotation direction switching signal that determines whether the rotation direction is forward rotation or reverse rotation according to the comparison result between the torque command value and the reference voltage. A rotation direction switching unit for outputting, a phase control unit for inputting the position detection signal and the rotation direction switching signal, and outputting a phase signal obtained by shifting the phase of the position detection signal according to the rotation direction switching signal; A motor current detection unit for detecting a motor current value flowing through the motor; a PWM control unit for comparing the torque command value with the motor current value to generate a PWM signal; the rotation direction switching signal; the phase signal; A motor drive unit that generates a motor drive signal by inputting a signal; and a motor drive unit that PWM drives the motor in accordance with the motor drive signal. Drive.   The motor driving apparatus according to claim 1, wherein the phase control unit outputs a phase signal whose phase is shifted by a predetermined amount within an electric angle range of 0 to 90 ° with respect to the position detection signal.   The phase control unit outputs a phase signal in phase with the induced voltage of the motor during forward rotation control, and a phase delayed by a predetermined amount within an electric angle range of 0 to 90 ° from the induced voltage of the motor during reverse rotation control. 2. The motor driving apparatus according to claim 1, wherein a signal is output.   A step of generating a position detection signal by detecting the rotor position of the motor to be driven, and a rotation direction switching signal for determining whether the rotation direction is forward rotation or reverse rotation according to the comparison result between the torque command value and the reference voltage Generating a phase signal obtained by shifting the phase of the position detection signal from the position detection signal and the rotation direction switching signal, detecting a motor current value flowing through the motor, and the torque command value. Generating a PWM signal by comparing the motor current values; generating a motor drive signal by inputting the rotation direction switching signal, the phase signal, and the PWM signal; and depending on the motor drive signal And a step of PWM driving the motor.   5. The motor drive according to claim 4, wherein the step of generating the phase signal generates a phase signal having a phase shifted by a predetermined amount within an electric angle range of 0 to 90 degrees with respect to the position detection signal. Method.   The step of generating the phase signal generates a phase signal that is in phase with the induced voltage of the motor during forward rotation control, and a predetermined amount within an electrical angle range of 0 to 90 ° from the induced voltage of the motor during reverse rotation control. 5. The motor driving method according to claim 4, wherein a delayed phase signal is generated.

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