The invention relates to the technical field of electric transmission and control, in particular to a speed sensor-less method for estimating the
rotor angle and the revolving speed of a permanent-
magnet synchronous motor. The method comprises the following steps: a. obtaining the
rotor flux linkage amplitude Psi<r> of a permanent-
magnet synchronous motor; b. transforming a
stator voltage fundamental component to be under an alpha beta coordinate
system to obtain u<alpha> and u<beta>; c. transforming the
stator current fundamental component to be under the alpha beta coordinate
system to obtain i<alpha> and i<beta>; d. carrying out highpass filtering on
stator current i<alpha> and i<beta> under the alpha beta coordinate
system, and obtaining the differential
estimation value sum of the stator current; e. obtaining a stator
counter electromotive force estimation value; f. obtaining a rotor revolving speed calculation value
omega<rC> and a
rotor angle calculation value theta<rC>; g. carrying out lowpass filtering on the rotor revolving speed calculation value
omega<rC> to obtain a rotor revolving speed
estimation value; h. obtaining the estimation value of a
rotor angle starting value; and i. obtaining a rotor angle estimation value. The method has the advantages that only forward calculation, instead of a feedback channel, exists in the method for estimating the rotor angle and revolving speed, and except filter delaying, no dynamic regulation process exists.