Patent ID: 9698713
Date: 2017-07-04
CPC Classifications: B60L,G01R,H02P,Y02T

Claim:
1. An apparatus for converting an offset of a current sensor, comprising: an inverter configured to convert a DC power into a three-phase AC current to supply it to an electric motor; a current detector comprising a plurality of current sensors configured to sense current output from the inverter; a filter configured to transform the current sensed by the current detector into a d-axis or q-axis current and to filter the transformed d-axis or q-axis current to extract a high frequency component; a RMS (root mean square) calculator configured to convert the high frequency component extracted from the filter into an effective (RMS) value; and a controller configured to, if the effective (RMS) value of the d-axis or q-axis current transformed by the RMS calculator is larger than a preset reference, obtain a DC offset corresponding to the smallest one of the effective (RMS) values of the d-axis or q-axis and correct each of the current sensors using the obtained DC offset, wherein the controller obtains the DC offset corresponding to the smallest one of the effective (RMS) values of the d-axis or q-axis by repeatedly increasing or decreasing a currently-set DC offset of each of the current sensors by a certain amount until the effective (RMS) values of the d-axis or q-axis gradually decreases and then increases.