US 6,583,593 B2 · Method and apparatus for position-sensorless motor control

Abstract

A method for position-sensorless motor control is provided, wherein a rotor-position estimation current signal is superimposed on the γ-axis direction component of a target current vector representing target currents of stator windings. The period of the current signal is an even multiple of a PWM carrier period and varies at random. The amplitude of the current signal increases with the amplitudes of the target currents. An even number of samples are obtained from the δ-axis direction component of a current vector representing detected currents of the stator windings in each period of the current signal. A discrete Fourier integration of the samples determines the amplitude of a current response to the current signal in the δ-axis direction. The γ-axis direction is corrected so that the current response substantially shrinks to zero in the δ-axis direction.

Claims28

Dependent claims

A position-sensorless motor control method comprising the steps of:

(A) determining a target current vector of stator windings;
(B) setting one of a rotor-position estimation current signal and a rotor-position estimation voltage signal, with varying the period thereof;
(C) detecting currents flowing through said stator windings;
(D) carrying out one of
(a) superimposing said rotor-position estimation current signal on a component of said target current vector in a first direction based on an estimated position (γ-axis direction, hereafter) of a rotor, thereby obtaining a target current vector with superimposed wave, and
(b) superimposing said rotor-position estimation voltage signal on a component of a target voltage vector corresponding to said target current vector in said first direction, thereby obtaining a target voltage vector with superimposed wave;
(E) supplying electric power to said stator windings through a motor driving device on the basis of one of said target current vector with superimposed wave and said target voltage vector with superimposed wave;
(F) measuring a current response to one of said rotor-position estimation current signal and said rotor-position estimation voltage signal, from a component of a current vector in a second direction having a fixed relation with said first direction, said current vector representing said currents detected in said detecting step;
and
(G) correcting said γ-axis direction on the basis of said current response.

7 more elements

A position-sensorless motor control method comprising the steps of:

(A) determining a target current vector of stator windings;
(B) setting one of a rotor-position estimation current signal and a rotor-position estimation voltage signal, with a predetermined period;
(C) detecting currents flowing through said stator windings;
(D) carrying out one of
(a) superimposing said rotor-position estimation current signal on a component of said target current vector in a first direction based on a γ-axis direction of a rotor, thereby obtaining a target current vector with superimposed wave, and
(b) superimposing said rotor-position estimation voltage signal on a component of a target voltage vector corresponding to said target current vector in said first direction, thereby obtaining a target voltage vector with superimposed wave;
(E) supplying electric power to said stator windings through a motor driving device on the basis of one of said target current vector with superimposed wave and said target voltage vector with superimposed wave;
(F) measuring a current response to one of said rotor-position estimation current signal and said rotor-position estimation voltage signal, from a component of a current vector in a second direction having a fixed relation with said first direction through sampling at least three times in each period of one of said rotor-position estimation current signal and said rotor-position estimation voltage signal, said current vector representing said currents detected in said detecting step;
and
(G) correcting said γ-axis direction on the basis of said current response.

7 more elements