# US 2017/0288588 A1 · Motor control device and motor control method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0288588 A1 - Document ID: US20170288588A1 - Status: Published application - Kind: A1 - Application number: 15/259,501 - Filed: 2016-09-08 - Published: 2017-10-05 - Earliest claimed: 2016-03-29 - Assignees: Mitsubishi Electric Corporation - Applicants: Mitsubishi Electric Corporation - Inventors: Tomoya TACHIBANA; Masahiro IEZAWA; Daiki MATSUURA; Noriyuki WADA - Web page: https://patentgrep.com/patent/US20170288588A1 ## CPC - H02P 21/22: Current control, e.g. using a current control loop - H02P 6/14: Electronic commutators - H02P 21/05: specially adapted for damping motor oscillations, e.g. for reducing hunting - H02P 27/08: with pulse width modulation - H02P 29/50: Reduction of harmonics - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS ## Abstract An object is to ensure torque accuracy by suppressing the occurrence of low-frequency fold-back noise caused by aliasing, and stable control performance with respect to environmental variations, such as angular errors, power voltage ripples, and so on. A motor control device includes a current detector (10) which, in generating a feedback current value on the basis of the detection result of a three-phase AC current supplied from an inverter (2) to a motor (1), generates a first current detection value based on a first sample timing and a second current detection value based on a second sample timing that is shorter than the first sample timing; a coordinates converter (11) which converts the coordinates of the first current detection value and the second current detection value to q and d axes; and a detection current processor (13) which generates a feedback current value from the coordinate conversion results. ## Claims ### Claim 1 A motor control device, comprising: an inverter which converts between direct current and alternating current; a motor which is connected to an output side of the inverter and is driven by receiving application of an AC voltage; a current sensor which detects AC current in the inverter; and a controller which performs current detection in respect of an output signal from the current sensor at two different sample timings, generates a feedback current value on the basis of a result of the current detection, and controls the inverter in such a manner that the feedback current value matches a current command value, wherein the controller includes a current detector for which there are previously set a first sample timing and a second sample timing having a shorter detection cycle than the first sample timing, as the two different sample timings, and which sequentially outputs, as the result of the current detection, a first current detection value based on the first sample timing and a second current detection value based on the second sample timing a coordinates converter which converts coordinates of the first current detection value detected as three phases to a first d-axis current value and a first q-axis current value, and converts coordinates of the second current detection value detected as three phases to a second d-axis current value and a second q-axis current value, and a detection current processor which generates the feedback current value for the d-axis and the q-axis, by using the first d-axis current and the second d-axis current to compute a d-axis feedback current value, and using the first q-axis current and the second q-axis current to compute a q-axis feedback current value. ### Claim 2 (depends on 1) The motor control device according to claim 1, wherein the second sample timing used in the current detector is set previously to no more than ½ of a carrier cycle. ### Claim 3 (depends on 1) The motor control device according to claim 1, wherein the controller further includes a low-pass filter which carries out a filtering process for passing a low-frequency component of the second d-axis current value and the second q-axis current value of which the coordinates have been converted by the coordinates converter; and the detection current processor generates the feedback current value by using the second d-axis current value and the second q-axis current value having undergone the filtering process by the low-pass filter. ### Claim 4 (depends on 2) The motor control device according to claim 2, wherein the controller further includes a low-pass filter which carries out a filtering process for passing a low-frequency component of the second d-axis current value and the second q-axis current value of which the coordinates have been converted by the coordinates converter; and the detection current processor generates the feedback current value by using the second d-axis current value and the second q-axis current value having undergone the filtering process by the low-pass filter. ### Claim 5 (depends on 1) The motor control device according to claim 1, wherein the current detector outputs the second current detection value by randomly selecting, at least once, the second sample timing within the detection cycle specified by the first sample timing. ### Claim 6 (depends on 2) The motor control device according to claim 2, wherein the current detector outputs the second current detection value by randomly selecting, at least once, the second sample timing within the detection cycle specified by the first sample timing. ### Claim 7 (depends on 1) The motor control device according to claim 1, wherein the controller further includes a high-pass filter which carries out a filtering process for passing a high-frequency component of the first d-axis current value and the first q-axis current value of which the coordinates have been converted by the coordinates converter; and the detection current processor generates the feedback current value by using the first d-axis current value and the first q-axis current value having undergone the filtering process by the high-pass filter. ### Claim 8 (depends on 2) The motor control device according to claim 2, wherein the controller further includes a high-pass filter which carries out a filtering process for passing a high-frequency component of the first d-axis current value and the first q-axis current value of which the coordinates have been converted by the coordinates converter; and the detection current processor generates the feedback current value by using the first d-axis current value and the first q-axis current value having undergone the filtering process by the high-pass filter. ### Claim 9 (depends on 7) The motor control device according to claim 7, wherein the detection current processor generates the feedback current value by using a value obtained by multiplying, by a predetermined coefficient, the first d-axis current value and the first q-axis current value having undergone the filtering process by the high-pass filter. ### Claim 10 (depends on 8) The motor control device according to claim 8, wherein the detection current processor generates the feedback current value by using a value obtained by multiplying, by a predetermined coefficient, the first d-axis current value and the first q-axis current value having undergone the filtering process by the high-pass filter. ### Claim 11 (depends on 1) The motor control device according to claim 1, wherein the detection current processor computes the d-axis feedback current value by finding a sum or difference of the first d-axis current and the second d-axis current, and computes the q-axis feedback current value by finding a sum or difference of the first q-axis current and the second q-axis current. ### Claim 12 (depends on 2) The motor control device according to claim 2, wherein the detection current processor computes the d-axis feedback current value by finding a sum or difference of the first d-axis current and the second d-axis current, and computes the q-axis feedback current value by finding a sum or difference of the first q-axis current and the second q-axis current. ### Claim 13 (depends on 1) The motor control device according to claim 1, wherein, when the controller controls the inverter using a PWM signal, the first sample timing used in the current detector is set to be longer than a computation cycle for generating the PWM signal. ### Claim 14 (depends on 2) The motor control device according to claim 2, wherein, when the controller controls the inverter using a PWM signal, the first sample timing used in the current detector is set to be longer than a computation cycle for generating the PWM signal. ### Claim 15 A motor control method executed in a motor control device which controls switching of an inverter in such a manner that a feedback current value generated on the basis of a detection result of three-phase AC current supplied from an inverter to a motor matches a current command value, the method comprising: a first step of detecting a first current detection value including three phases for the detection result of the three-phase AC current, by using a first sample timing; a second step of detecting a second current detection value including three phases for the detection result of the three-phase AC current, by using a second sample timing which is set to be a shorter detection cycle than the first sample timing; a third step of converting coordinates of the first current detection value detected in the first step, to a first d-axis current value and a first q-axis current value; a fourth step of converting coordinates of the second current detection value detected in the second step, to a second d-axis current value and a second q-axis current value; a fifth step of generating the feedback current value in relation to the d axis by computing a d-axis feedback current value using the first d-axis current detected in the third step and the second d-axis current detected in the fourth step; and a sixth step of generating the feedback current value in relation to the q axis by computing a q-axis feedback current value using the first q-axis current detected in the third step and the second q-axis current detected in the fourth step.