JP2007166780A - Brushless motor driver and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brushless motor driver that reduces torque fluctuation of a brushless motor. <P>SOLUTION: This brushless motor driver includes the brushless motor 1, a speed control means 2 that controls the speed by comparing an output of a revolution detector 1a of the brushless motor 1 with reference speed, a phase control means 3 that controls the phase by comparing an output of the revolution detector 1a with a reference phase when the speed control means 2 controls the speed within a predetermined revolution error, a sine-wave signal means 4 that outputs a sine-wave signal according to the output signals of the revolution detector 1a and a rotor magnet position detector 1b, a 120° signal means 5 that outputs a rectangular-wave signal from the signal of the rotor magnet position detector 1b, a signal selection means 6 that selects the sine-wave signal means 4 when the speed control means 2 controls the speed within a predetermined revolution error and that selects the 120° signal means 5 when the speed is out of that range, and a drive means 7 turns on the brushless motor 1 at the timing in accordance with the output of the signal selection means 6 and that outputs a current according to the signals of the speed control means 2 and the phase control means 3 to the brushless motor 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a brushless motor driving device and an image forming apparatus such as a laser beam printer and a copying machine equipped with the brushless motor driving device.

In relation to the brushless motor driving device, for example, Patent Literature 1 discloses the following technique. A wide angle energization with an electrical angle of 150 degrees is performed from the stop state to a certain set rotational speed, and energization is performed with an electrical angle of 120 degrees when driven beyond a certain set rotational speed. The generation of the wide-angle energization is performed using a signal obtained by electrically interpolating one cycle of the position detection signal.
Japanese Patent Application Laid-Open No. 2002-354887

In the prior art, when wide-angle energization is performed at a set rotation speed or higher, the rotation speed fluctuates at a set rotation speed or higher, and thus does not match the target energization angle during acceleration, deceleration, or load fluctuation. In addition, when the position cycle of the position detection signal is interpolated, a stable signal is not output due to signal accuracy and processing delay. There is a problem that the torque is not stable due to the individual results, speed and phase fluctuations.
An object of this invention is to provide the brushless motor drive device which can reduce the torque fluctuation of a brushless motor.

  In order to achieve the above object, a first aspect of the invention relates to a brushless motor having a rotational speed detector and a rotor magnet position detector, and an output of the rotational speed detector of the brushless motor is compared with a reference speed to obtain a speed. Speed control means for controlling, phase control means for comparing the output of the rotation speed detector of the brushless motor with a reference phase when the speed control means falls within a predetermined rotation speed error range, and phase control, and the brushless motor A sine wave signal means for outputting a sine wave signal in accordance with the output signals of the rotation speed detector and the rotor magnet position detector, and a rectangular wave signal from the rotor magnet position detector signal of the brushless motor. When the signal means and the speed control means are within the predetermined rotation speed error range, the sine wave signal means is selected, and otherwise the 120 ° signal means is selected. And a drive means for energizing the brushless motor at a timing according to the output of the signal selection means and outputting a current according to the signal of the speed control means and the phase control means to the brushless motor. It features a brushless motor drive device.

  According to a second aspect of the present invention, there is provided a brushless motor having a rotational speed detector and a rotor magnet position detector, a clock signal means, and a speed control means for setting a reference speed by dividing the signal of the clock signal means. A phase control unit that divides the signal of the clock signal unit to set a reference phase, and the signal of the clock signal unit is divided when the speed control signal of the speed control unit falls within a predetermined rotation speed error range. The sine wave signal means for outputting a sine wave signal according to the signal and the output signal of the rotation speed detector, and a 120 ° signal means for outputting a rectangular wave signal from the signal of the rotor magnet position detector of the brushless motor, A signal selection means for selecting a sine wave signal means when the speed control means is within a predetermined rotation speed error range; otherwise, a 120 ° signal means; and the signal selection means A brushless motor driving device comprising: a driving unit that energizes the brushless motor at a timing corresponding to the output of the stage and outputs a current corresponding to a signal of the speed control unit and the phase control unit to the brushless motor; To do.

According to a third aspect of the present invention, in the brushless motor driving device according to the first or second aspect, the sine wave signal means generates a sine wave signal so that a current value of the brushless motor detected by the driving means is minimized. It features a brushless motor drive that advances the phase.
According to a fourth aspect of the present invention, in the brushless motor driving device according to any one of the first to third aspects, when a plurality of the brushless motors are driven, the sine wave data of the sine wave signal means is shared and used. It features a brushless motor driving device.
According to a fifth aspect of the present invention, there is provided an image forming apparatus equipped with the brushless motor driving device according to any one of the first to fourth aspects.

  A brushless motor driving apparatus according to the present invention includes a brushless motor having a rotational speed detector and a rotor magnet position detector, speed control means for performing speed control by comparing the output of the rotational speed detector of the brushless motor and a reference speed. When the speed control means falls within a predetermined rotational speed error range, phase control means for performing phase control by comparing the output of the rotational speed detector of the brushless motor with a reference phase, and the rotational speed detector and rotor of the brushless motor A sine wave signal means for outputting a sine wave signal in accordance with an output signal from the magnet position detector; a 120 ° signal means for outputting a rectangular wave signal from the signal of the rotor magnet position detector of the brushless motor; and the speed control. The signal selection means for selecting the sine wave signal means when the means is within the predetermined rotation speed error range and selecting the 120 ° signal means otherwise. And a driving means for energizing the brushless motor at a timing corresponding to the output of the signal selection means and outputting a current corresponding to the signal of the speed control means and the phase control means to the brushless motor. The torque fluctuation of the brushless motor can be reduced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram of a brushless motor driving apparatus according to a first embodiment of the present invention. In FIG. 1, a brushless motor 1 includes a rotation number detector 1a and a rotor magnet position detector (hereinafter referred to as position detector) 1b. The speed control means 2 controls the speed by comparing the output of the rotation speed detector 1a of the brushless motor 1 with a reference speed. The phase control means 3 performs phase control by comparing the output of the rotational speed detector 1a with a reference phase when the speed control means 2 falls within a predetermined rotational speed.
The sine wave signal means 4 outputs a sine wave signal according to the output signals of the rotation speed detector 1a and the position detector 1b when the speed control signal of the speed control means 2 falls within a predetermined rotation speed. The 120 ° signal means 5 outputs a rectangular wave signal from the signal of the position detector 1b.
The signal selection means 6 selects the sine wave signal means 4 when the speed control means 2 is within a predetermined rotational speed, and selects the 120 ° signal means 5 except for the predetermined rotational speed. The drive means 7 energizes the brushless motor 1 at a timing according to the output of the signal selection means 6, and outputs a current according to the signals of the speed control means 2 and the phase control means 3 to the brushless motor 1. .

FIG. 2 is a detailed view of a main part of the brushless motor driving apparatus shown in FIG. 1, and FIG. 3 is an output waveform diagram of each part shown in FIG. The speed control means 2 and the phase control means 3 perform control according to the signal of the rotation speed detector 1a of the brushless motor 1, respectively. When the speed error detected by the speed control means 2 falls within a predetermined range and the rotation is stabilized, the phase control means 3 operates to perform phase control.
The sine wave signal means 4 is reset at the edge of the signal of the position detector, the counter 41 is operated using the signal 4b of the rotation speed detector 1a as a clock, and the data circuit 42 receives the data 4a corresponding to the value of the counter 41. Output to the signal selection means 6. In the signal selection means 6, the speed control data and the phase control data are added by the adder circuit 61, and the sine wave data is further multiplied by the multiplier circuit 62.
Further, the sine wave data is converted into a rectangular wave 6a by the rectangular wave circuit 63 every 180 degrees. The selection circuit A64 selects the output of the multiplication circuit 62 when the speed error is within a predetermined range, and selects the addition circuit 61 otherwise. The DAC circuit 66 DA-converts the signal from the selection circuit A64. The selection circuit B65 selects the signal of the rectangular wave circuit 63 when the speed error is within a predetermined range, and selects the signal 5a of the 120 ° signal means 5 otherwise.
The driving means 7 performs PWM conversion of the signal of the DAC circuit 66 by the PWM conversion circuit 71. The drive synthesis circuit 72 synthesizes the signal from the PWM conversion circuit 71 and the signal from the selection circuit B65 and outputs the synthesized signal to the brushless motor 1 as a drive signal.

FIG. 4 is a block diagram of a brushless motor driving apparatus according to the second embodiment of the present invention. A clock signal means 8 is added to the configuration of the first embodiment shown in FIG. The speed control means 2 divides the signal of the clock signal means 8 to set the reference speed, and the phase control means 3 divides the signal of the clock signal means 8 to set the reference phase.
When the speed control signal of the speed control means 2 falls within a predetermined rotational speed error range, the sine wave signal means 4 responds to the signal obtained by dividing the signal of the clock signal means 8 and the output signal of the rotational speed detector 1a. Sine wave signal is output stably.

The image forming apparatus of the present invention is equipped with the brushless motor driving device of the first embodiment or the second embodiment, and improves the rotational accuracy of a load driven by the brushless motor 1 and reduces vibration and noise. can do.
The brushless motor 1 is delayed in energization phase when the load is large or the current is large. Therefore, the sine wave signal means 4 advances the phase of the sine wave signal so that the brushless motor current value detected by the drive means 7 is minimized. Thereby, the rotational accuracy of the load driven by the brushless motor 1 can be improved, and vibration and noise can be reduced.
When a plurality of brushless motors 1 are driven, the number of circuit elements can be reduced by using the sine wave signal means 4 in common.

It is a lineblock diagram of the brushless motor drive concerning a 1st embodiment of the present invention. It is a principal part detail drawing of the brushless motor drive device shown in FIG. FIG. 3 is an output waveform diagram of each unit illustrated in FIG. 2. It is a block diagram of the brushless motor drive device which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

  1 brushless motor, 2 speed control means, 3 phase control means, 4 sinusoidal signal means, 5 120 ° signal means, 6 signal selection means, 7 drive means

Claims (5)

  A brushless motor having a rotational speed detector and a rotor magnet position detector, speed control means for comparing the output of the rotational speed detector of the brushless motor with a reference speed and controlling the speed, and the speed control means having a predetermined rotation Phase control means for comparing the output of the rotational speed detector of the brushless motor with a reference phase and controlling the phase when it is within a numerical error range, and output signals of the rotational speed detector of the brushless motor and the rotor magnet position detector. In response, the sine wave signal means for outputting a sine wave signal, the 120 ° signal means for outputting a rectangular wave signal from the signal of the rotor magnet position detector of the brushless motor, and the speed control means within a predetermined rotation speed error range The signal selecting means for selecting the sine wave signal means and selecting the 120 ° signal means for the others, and the output of the signal selecting means. A brushless motor drive device comprising: drive means for energizing the brushless motor at a corresponding timing and outputting a current corresponding to a signal from the speed control means and the phase control means to the brushless motor.   A brushless motor having a rotational speed detector and a rotor magnet position detector, a clock signal means, a speed control means for setting a reference speed by dividing the signal of the clock signal means, and a signal of the clock signal means A phase control means for dividing and setting a reference phase; and a signal obtained by dividing the signal of the clock signal means when the speed control signal of the speed control means falls within a predetermined rotational speed error range, and the rotational speed detector The sine wave signal means for outputting a sine wave signal in accordance with the output signal, a 120 ° signal means for outputting a rectangular wave signal from the signal of the rotor magnet position detector of the brushless motor, and the speed control means for a predetermined rotation A signal selecting means for selecting a sine wave signal means when it is within a numerical error range, and a 120 ° signal means for other cases, and a type corresponding to the output of the signal selecting means. A brushless motor driving apparatus comprising: a driving means for supplying current to the brushless motor by supplying current to the brushless motor in response to a signal from the speed control means and the phase control means.   3. The brushless motor driving apparatus according to claim 1, wherein the sine wave signal means advances the phase of the sine wave signal so that the current value of the brushless motor detected by the driving means is minimized. Brushless motor drive device.   4. The brushless motor driving apparatus according to claim 1, wherein when the plurality of brushless motors are driven, the sine wave data of the sine wave signal means is shared and used. Drive device.   An image forming apparatus equipped with the brushless motor driving device according to claim 1.

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