# US 11,121,659 B2 · Evaluation device, evaluation method and control device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,121,659 B2 - Document ID: US11121659B2 - Status: Granted - Kind: B2 - Application number: 16/485,783 - Filed: 2018-01-30 - Published: 2020-02-13 - Granted: 2021-09-14 - Earliest claimed: 2017-03-10 - Assignees: OMRON Corporation - Applicants: OMRON Corporation - Inventors: Yasushi Ono; Mamoru Egi - Web page: https://patentgrep.com/patent/US11121659B2 ## CPC - H02P 21/22: Current control, e.g. using a current control loop - H02P 23/14: Estimation or adaptation of motor parameters, e.g. rotor time constant, flux, speed, current or voltage - H02P 21/09: Field phase angle calculation based on rotor voltage equation by adding slip frequency and speed proportional frequency - G06F 1/3203: Power management, i.e. event-based initiation of a power-saving mode - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract Provided is an evaluation device that determines the necessity of a notch filter inserted in a control system that controls an electric motor by closed loop control. The evaluation device includes: a characteristic acquisition parts for changing a parameter associated with a characteristic of the notch filter from a first value, which is a prescribed value, to a second value, and acquiring a change in a frequency response characteristic of the electric motor when the notch filter is applied; and a determination parts for determining the necessity of the notch filter based on the change in the frequency response characteristic that has been acquired. ## Claims ### Claim 1 An evaluation device that determines the necessity of a notch filter inserted in a control system that controls an electric motor by closed loop control, the evaluation device comprising: a characteristic acquisition parts for changing a parameter associated with a characteristic of the notch filter from a first value, which is a prescribed value, to a second value, and acquiring a change in a frequency response characteristic of the electric motor when the notch filter is applied; and a determination parts for determining the necessity of the notch filter based on the change in the frequency response characteristic that has been acquired, wherein the parameter is a parameter that represents a width or a depth of the notch filter, and the second value is a parameter having a filter effect smaller than the first value. ### Claim 2 (depends on 1) The evaluation device according to claim 1, wherein the characteristic acquisition parts estimates a range of the parameter in which the control system can maintain a stable state based on an already acquired frequency response characteristic, and sets the second value within the range. ### Claim 3 (depends on 2) The evaluation device according to claim 2, wherein the characteristic acquisition parts estimates that the control system can maintain a stable state when a frequency response characteristic after setting the second value as the parameter is, (1) a first gain at a first frequency at which a phase delay reaches 180 degrees becomes less than or equal to a predetermined value, and (2) a peak of a gain in a frequency band higher than the first frequency is less than or equal to the first gain. ### Claim 4 (depends on 2) The evaluation device according to claim 2, wherein the characteristic acquisition parts detects that a parameter having a smaller influence on the control system than the first value exists within the range, and notifies a user of a detection result. ### Claim 5 (depends on 1) The evaluation device according to claim 1, wherein the notch filter comprises a plurality of notch filters, and the determining is performed for each of the plurality of notch filters. ### Claim 6 (depends on 5) The evaluation device according to claim 5, wherein the determination parts notifies a user of a notch filter determined to be unnecessary among the plurality of notch filters. ### Claim 7 A control device that controls an electric motor by closed loop control, the control device comprising: a speed control parts for generating a torque command for rotating the electric motor; a filter parts for applying a notch filter to the torque command; a speed detection parts for detecting a rotational speed of the electric motor; a characteristic acquisition parts for changing a parameter associated with a characteristic of the notch filter from a first value, which is a prescribed value, to a second value, and acquiring a change in a frequency response characteristic of the electric motor when the notch filter is applied; and a determination parts for determining the necessity of the notch filter based on the change in the frequency response characteristic that has been acquired, wherein the parameter is a parameter that represents a width or a depth of the notch filter, and the second value is a parameter having a filter effect smaller than the first value. ### Claim 8 (depends on 7) The control device according to claim 7, wherein the filter parts disables a notch filter determined to be unnecessary by the determination parts. ### Claim 9 (depends on 7) The control device according to claim 7, wherein the characteristic acquisition parts estimates a range of the parameter in which the control system can maintain a stable state based on an already acquired frequency response characteristic, and sets the second value within the range. ### Claim 10 (depends on 9) The control device according to claim 9, wherein the characteristic acquisition parts estimates that the control system can maintain a stable state when a frequency response characteristic after setting the second value as the parameter is, (1) a first gain at a first frequency at which a phase delay reaches 180 degrees becomes less than or equal to a predetermined value, and (2) a peak of a gain in a frequency band higher than the first frequency is less than or equal to the first gain. ### Claim 11 (depends on 9) The control device according to claim 9, wherein the characteristic acquisition parts detects that a parameter having a smaller influence on the control system than the first value exists within the range, and notifies a user of a detection result. ### Claim 12 (depends on 11) The control device according to claim 11, wherein the filter parts applies the detected parameter to a notch filter. ### Claim 13 (depends on 7) The control device according to claim 7, wherein the notch filter comprises a plurality of notch filters, and the determining is performed for each of the plurality of notch filters. ### Claim 14 (depends on 13) The control device according to claim 13, wherein the determination parts notifies a user of a notch filter determined to be unnecessary among the plurality of notch filters. ### Claim 15 An evaluation method performed by an evaluation device that determines the necessity of a notch filter inserted in a control system that controls an electric motor by closed loop control, the evaluation method comprising: a characteristic acquisition step for changing a parameter associated with a characteristic of the notch filter from a first value, which is a prescribed value, to a second value, and acquiring a change in a frequency response characteristic of the electric motor when the notch filter is applied; and a determination step for determining the necessity of the notch filter based on the change in the frequency response characteristic that has been acquired, wherein the parameter is a parameter that represents a width or a depth of the notch filter, and the second value is a parameter having a filter effect smaller than the first value.