# US 2013/0278185 A1 · Ac motor control apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0278185 A1 - Document ID: US20130278185A1 - Status: Published application - Kind: A1 - Application number: 13/867,297 - Filed: 2013-04-22 - Published: 2013-10-24 - Earliest claimed: 2012-04-22 - Assignees: Denso Corporation - Applicants: Denso Corporation - Inventors: Takashi SUZUKI; Takeshi ITOH; Hirofumi KAKO - Web page: https://patentgrep.com/patent/US20130278185A1 ## CPC - H02P 21/14: Estimation or adaptation of machine parameters, e.g. flux, current or voltage - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS ## Abstract A control apparatus for an AC motor includes a current sensor and an estimation section. The current sensor detects current flowing through one phase of the motor. The estimation section repeats an estimation process. In the estimation process, d-axis and q-axis current estimation values are calculated based on the presently detected current of the one phase and a previous current estimation value of another phase of the motor, and a present current estimation value of each phase is calculated based on smoothed values of the d-axis and q-axis current estimation values. The estimation section performs the estimation process based on a phase lag element. The phase lag element is a difference between the presently detected current and a previous current estimation value of the one phase or the previously detected current. ## Claims ### Claim 1 A control apparatus for controlling a three-phase AC motor, the control apparatus comprising: a current sensor configured to detect electric current flowing through one phase of the AC motor, the one phase being defined as a sensor phase; and a current estimation section configured to repeatedly perform a current estimation process in a predetermined cycle, wherein in the current estimation process, a d-axis current estimation value and a q-axis current estimation value in a rotating coordinate system of the AC motor are calculated based on a present current detection value of the sensor phase and a previous current estimation value of another phase of the AC motor, the present current detection value being defined as the current presently detected by the current sensor, in the current estimation process, a present current estimation value of each of the sensor phase and the other phase of the AC motor is calculated based on a smoothed d-axis current estimation value and a smoothed q-axis current estimation value into which the d-axis current estimation value and the q-axis current estimation value are respectively smoothed, the current estimation section performs the current estimation process based on a phase lag element of the sensor phase, and the phase lag element of the sensor phase is a difference between the present current detection value and one of a previous current estimation value of the sensor phase and a previous current detection value of the sensor phase, the previous current detection value being defined as the current previously detected by the current sensor. ### Claim 2 (depends on 1) The control apparatus according to claim 1, wherein the current estimation section corrects the d-axis current estimation value and the q-axis current estimation value based on the phase lag element of the sensor phase, and the current estimation section calculates the present current estimation value of each of the sensor phase and the other phase by using the corrected d-axis current estimation value and the corrected q-axis current estimation value. ### Claim 3 (depends on 2) The control apparatus according to claim 2, wherein the current estimation section calculates a d-axis current correction value and a q-axis current correction value in the rotating coordinate system based on the phase lag element of the sensor phase, and the current estimation section corrects the d-axis current estimation value and the q-axis current estimation value by using the d-axis current correction value and the q-axis current correction value, respectively. ### Claim 4 (depends on 1) The control apparatus according to claim 1, wherein the current estimation section corrects the present current detection value based on the phase lag element of the sensor phase, and the current estimation section calculates the d-axis current estimation value and the q-axis current estimation value based on the corrected present current detection value of the sensor phase and the previous current estimation value of the other phase. ### Claim 5 (depends on 4) The control apparatus according to claim 4, wherein the current estimation section calculates a correction value of the sensor phase based on the phase lag element of the sensor phase, and the current estimation section corrects the present current detection value by using the correction value of the sensor phase. ### Claim 6 (depends on 1) The control apparatus according to claim 1, further comprising: a control section configured to control energization of the AC motor based on the d-axis current estimation value and the q-axis current estimation value. ### Claim 7 (depends on 2) The control apparatus according to claim 2, further comprising: a control section configured to control energization of the AC motor based on the d-axis current estimation value and the q-axis current estimation value. ### Claim 8 (depends on 3) The control apparatus according to claim 3, further comprising: a control section configured to control energization of the AC motor based on the d-axis current estimation value and the q-axis current estimation value. ### Claim 9 (depends on 4) The control apparatus according to claim 4, further comprising: a control section configured to control energization of the AC motor based on the d-axis current estimation value and the q-axis current estimation value. ### Claim 10 (depends on 5) The control apparatus according to claim 5, further comprising: a control section configured to control energization of the AC motor based on the d-axis current estimation value and the q-axis current estimation value.