公开(公告)号：US11424708B2

公开(公告)日：2022-08-23

申请号：US17347551

申请日：2021-06-14

Applicant: DELTA ELECTRONICS, INC.

Inventor： Shao-Kai Tseng ,  Yuan-Qi Hsu ,  Sheng-Han Wu ,  Sheng-Chieh Chang

IPC: H02P23/08

Abstract: An estimation method for estimating a rotor frequency of a motor during freewheeling, includes: applying a fixed input voltage and one selected from a plurality of stator frequencies to the motor sequentially so as to perform frequency scanning; detecting a stator current value of the motor corresponding to the selected stator frequency; calculating a stator current slope of the stator current values sequentially; defining a target period from a start point where the stator current slope varies from positive to negative to an end point where the stator current slope varies from negative to positive; and determining that a difference between the scanned stator frequency and the rotor frequency is within a preset value, then designating any of the corresponding stator frequencies during the target period as an estimated value of the rotor frequency.