US 8,232,757 B2 · Rotational position detecting method for AC servomotor and simple encoder

Abstract

A motor rotational position detecting method detects the magnetic pole position of each phase of a three-phase AC servomotor, generates a three-phase square wave signal having a phase difference of 120 degrees, allocates data on the rotational position of a motor shaft to the edge of each square wave signal, calculates the rotational speed of the motor on the basis of the elapsed time from the previous edge detection point to this time edge detection point, and estimates the rotational position of the motor shaft at a certain period and outputs it on the basis of the rotational speed of the motor and the rotational position allocated to this time edge in the rotational section from this time edge detection point to the next edge detection point. As a result, a detection mechanism can be constructed with a small installation space and at low cost and the output of a high-resolution encoder can be obtained in a pseudo manner.

Claims20

Dependent claims

A method for detecting a rotational position of an AC servomotor, comprising:

detecting the magnetic pole position of each phase of a three-phase AC servomotor;
generating a three-phase square wave signal having a phase difference of 120 degrees as a rotational shaft of the AC servomotor rotates;
outputting, as a rotational position of the motor shaft, rotational position data of the motor shaft allocated in advance to a detected edge of a square wave signal each time the edge is detected;
computing the rotational speed of the motor each time the edge of a square wave signal is detected, on the basis of the time elapsed from the previous edge detection time to a current edge detection time;
and
estimating the rotational position of the motor shaft at a certain period and outputting the estimated rotational position as the rotational position of the motor shaft in a rotational section from the current edge detection time to the next edge detection time, on the basis of the computed rotational speed of the motor and the rotational position allocated to the current edge.

3 more elements

A method for detecting a rotational position of an AC servomotor, comprising:

detecting the magnetic pole position of each phase of a two-phase AC servomotor;
generating a two-phase square wave signal having a phase difference of 90 degrees as a rotational shaft of the AC servomotor rotates;
outputting, as a rotational position of the motor shaft, rotational position data of the motor shaft allocated in advance to a detected edge of a square wave signal each time the edge is detected;
computing the rotational speed of the motor each time the edge of a square wave signal is detected, on the basis of the time elapsed from the previous edge detection time to a current edge detection time;
and
estimating the rotational position of the motor shaft at a certain period and outputting the estimated rotational position as the rotational position of the motor shaft in a rotational section from the current edge detection time to the next edge detection time, on the basis of the computed rotational speed of the motor and the rotational position allocated to the current edge.

3 more elements

Dependencies are inferred from the claim text.

Rotational position detecting method for AC servomotor and simple encoder

Life of this patent

Rotational position detecting method for AC servomotor and simple encoder

Life of this patent

Abstract

Claims20