Patent ID: 9660562
Date: 2017-05-23
CPC Classifications: H02P

Claim:
1. An apparatus for determining start of an electric machine, the apparatus comprising: a current converter configured to output a first AC (Alternating Current) signal corresponding to a frequency component of at least one phase current input to a 3-phase motor from an inverter and to output a second AC signal having a phase angle that lags a phase angle of the first AC signal by 90°; an estimator configured to estimate a frequency of the second AC signal; a bandwidth decision unit configured to determine a control bandwidth of the estimated frequency estimated by the estimator; and a determiner configured to determine whether the 3-phase motor has started according to a difference between the estimated frequency and a frequency of an output voltage of the inverter, wherein the control bandwidth is determined according to a gain of the estimator, and wherein the gain of the estimator is selected as a value higher than an operation frequency of the 3-phase motor.