Japan Servo Co.,ltd.

Yoshihiro Okumatsu

Yasuo Matsuda

Yoshifumi Kuwano

Akio Takemori

Atsuo Kawamura

Shoji Ohiwa

Hiroaki Taka

Yukinari Takahashi

Yoshifumi c/o Japan Servo Co Ltd Kuwano

Akio c/o Japan Servo Co Ltd Takemori

Yasuo c/o Japan Servo Co Ltd Matsuda

A motor control system according to the present invention comprises a magnetic encoder including a magnetic drum fixed to an output shaft of a motor and a magnetic sensor provided against a periphery of the magnetic drum through a space, an angle calculating unit for calculating a rotational angle of the motor from an output of the magnetic encoder, an angle estimating unit for estimating the rotational angle, an error angle calculating unit for finding an error angle from an calculated angle calculated by the angle calculating unit and an estimated angle estimated by the angle estimating unit, an error-correction value calculating unit for calculating from the error angle an error-correction value that corresponds to the rotational angle, a correction calculating unit for calculating a correction angle or a correction speed from the calculated angle and the error-correction value, and a motor operation controlling unit for outputting to an inverter a voltage command value that corresponds to the correction angle or the correction speed.

Motor control system

A stepping motor driver which drives a stepping motor for position and speed control. The stepping motor driver comprises: a current control means which outputs values corresponding to applied voltages; current sensors which detect phase currents; and a magnetic pole position estimation unit which uses the values corresponding to applied voltages and detected phase current values as outputs of the current sensors to obtain a magnetic pole position estimate. The magnetic pole position estimation unit calculates a magnetic pole position estimate from speed electromotive force estimates or from differences between phase currents at zero speed and detected phase current values.

Stepping motor driver

The stepping motor driver comprises an inverter for feeding stepped currents to windings of a stepping motor, a position detector for obtaining a detected angle of a rotor of the stepping motor and a current controller for controlling the inverter. In a d-q rotational coordinate system in which the d-axis is in the direction of the magnetic flux of the rotor and the q-axis is in the direction perpendicular to the d-axis, an excitation angle for a winding is determined from a d-axis component and a q-axis component of a command current to the winding, a lead angle control signal is computed from the excitation angle, and a phase of an applied voltage to the stepping motor is controlled using the lead angle control signal.

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Miyazaki, Japan

Yoshihiro Okumatsu