Minebea Mitsumi Inc.

Kei Yamazaki

Kazuo Takada

Shigeki Miyaji

Tetsuya Seki

Ayaka Shimada

Takayuki Matsui

Haruka Miyaji

Koichi Takeda

A control device for a stepping motor capable of hold control that can smoothly reduce an excitation current at a rotation stopping time of the stepping motor is provided. A control device () for a stepping motor () causes an excitation current to flow in a plurality of coils to rotate a rotor. The control device () includes a driving circuit () that applies a driving voltage to the coils, and a control circuit () that controls the driving voltage. The control circuit () performs hold control to move the rotor to a predetermined stop position by changing a magnitude of the excitation current flowing in the coils so that the magnitude of the excitation current becomes close to a target current value that gradually decreases, in a hold time period at a rotation stopping time of the stepping motor (). The control circuit () sets an operation mode of the driving circuit () at an operation mode corresponding to a comparison result of the magnitude of the excitation current and the target current value, of a plurality of operation modes, at each predetermined period in the hold time period. The plurality of operation modes include a charge mode to increase the excitation current and a first attenuation mode to attenuate the excitation current.

Control device for stepping motor and control method for stepping motor

A motor drive control device has a controller and a driver. The controller generates a control signal for controlling driving of a two-phase stepping motor so as to alternately repeat one-phase excitation in which a coil of one phase in coils of two phases of the two-phase stepping motor is excited and two-phase excitation in which the coils of two phases in the coils of the two phases are excited. The driver drives the coils of the two phases, based on the control signal. The controller determines, based on a back electromotive force generated in the coil that was not excited during the one-phase excitation, a period of performing the one-phase excitation, and determines, based on the period of the one-phase excitation performed before the two-phase excitation, a period of performing the two-phase excitation.

Motor drive control device, motor unit, and motor drive control method

In order to suppress high-frequency noise in micro-step driving of a stepping motor, a motor control device () includes an H bridge circuit () and control means for driving a switching element of the H bridge circuit () with a PWM signal and for setting a charge mode, a fast attenuation mode, or a slow attenuation mode for a motor coil. In a range from an electrical angle where the reference current value starts descending to an electrical angle of +52&#xb0;, the control means switches the H bridge circuit () every PWM cycle to the charge mode and then to the slow attenuation mode. In a range exceeding +52&#xb0; and to +90 degrees where the reference current value starts ascending, the control means switches the H bridge circuit () every PWM cycle to the charge mode and, if the motor current exceeds the reference current value, then the control means switches it to the fast attenuation mode and further to the slow attenuation mode.

Motor current control device and motor current control method

A control device for a stepping motor gradually increases an absolute value of the excitation current in phase A from when the start until the end of the hold period such that the amount of change in the excitation current per unit time is smaller than or equal to a first predetermined value. From the start of the hold period until a predetermined time elapses, an absolute value of the excitation current in phase B gradually increases such that the amount of change in the excitation current per unit time is smaller than or equal to the first predetermined value. By the end of the hold period after the predetermined time has elapsed, the excitation current in phase B reaches zero. When the hold period ends, one-phase excitation operation starts and the excitation current flows in phase A first with the same polarity as at the end of the hold period.

A motor drive controller capable of taking measures against vibration or noise of a motor is provided. The motor drive controller configured to drive a stepping motor in microstepping mode controls the number of PWM (Pulse Width Modulation) cycles contained in one microstep cycle. More specifically, the number of PWM cycles contained in one microstep cycle is controlled so that a vibration contained in a current waveform determined by the number of PWM cycles contained in one microstep cycle does not approximate the natural frequency of the stepping motor.

Motor drive controller, control method for motor drive controller, control program for motor drive controller, and method for determining number of divisions of basic step angle

In accordance with one aspect of the present disclosure, a motor drive control device is a motor drive control device performing PWM (Pulse Width Modulation) control of a motor, wherein harmonics of a fundamental frequency for PWM control of the motor are included in noise occurring from the motor; the fundamental frequency for PWM control is larger than a frequency corresponding to a bandwidth of a predetermined radio frequency band a communication apparatus uses; and frequencies of continuous harmonic components of the fundamental frequency for PWM control appear before and after the predetermined radio frequency band.

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Ota-ku, Japan

Kei Yamazaki