# US 2014/0191699 A1 · Motor Control with Voltage Harmonic Shaping > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0191699 A1 - Document ID: US20140191699A1 - Status: Published application - Kind: A1 - Application number: 14/123,622 - Filed: 2012-05-16 - Published: 2014-07-10 - Earliest claimed: 2011-06-03 - Assignees: TRW Inc. - Inventors: Christoper David Dixon - Web page: https://patentgrep.com/patent/US20140191699A1 ## CPC - H02P 23/14: Estimation or adaptation of motor parameters, e.g. rotor time constant, flux, speed, current or voltage - H02P 21/05: specially adapted for damping motor oscillations, e.g. for reducing hunting - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS ## Abstract A control system for an electric motor (10) comprises a current sensing means (14) arranged to produce a current sensing output indicative of electric current in the motor, current control means (20) arranged to receive a current demand and to control voltages applied to the motor, and correction means (26) arranged to receive the current sensing output and the current demand, and use them to generate a correction signal. The current control means (20) is arranged to receive the correction signal and to use the correction signal to correct the voltages applied to the motor. ## Claims ### Claim at position 1 1-15. (canceled) ### Claim 16 A control system for an electric motor comprising: a current sensing means arranged to produce a current sensing output indicative of electric current in an electric motor; current control means arranged to receive a current demand and to control voltages applied to the electric motor; and correction means arranged to receive and use the current sensing output and the current demand to generate a correction signal, wherein the current control means is arranged to receive and use the correction signal to correct voltages applied to the electric motor. ### Claim 17 (depends on 16) The control system according to claim 16 wherein the correction means is arranged to identify a distortion frequency and to determine, from the current sensing output and the current demand, a component of the current in the electric motor at the distortion frequency. ### Claim 18 (depends on 17) The control system according to claim 17 wherein the correction signal is arranged to indicate a magnitude of the distortion frequency component. ### Claim 19 (depends on 16) The control system according to claim 16 wherein the correction means is arranged to generate a distortion signal from the current sensing output and the current demand. ### Claim 20 (depends on 16) The control system according to claim 16 wherein the correction means is arranged to perform a comparison between at least a component of the current sensing output and at least a component of the current demand to at least partially isolate the distortion frequency component from a fundamental component of the current in the electric motor. ### Claim 21 (depends on 16) The control system according to claim 16 wherein the current control means is arranged to output a voltage demand indicative of voltages to be applied to the electric motor, and wherein the correction signal is arranged to indicate corrections to the voltage demand. ### Claim 22 (depends on 17) The control system according to claim 17 wherein the correction means is arranged to transform the current sensing output or the distortion signal so that the identified component becomes a DC component and to measure the magnitude of the DC component. ### Claim 23 (depends on 16) The control system according to claim 16 wherein the correction means is arranged to operate in a high speed mode and a low speed mode and, in the low speed mode, to use the current demand to generate the correction signal and, in the high speed mode, at least partially isolate the distortion frequency component from a fundamental component of the current sensing output by filtering. ### Claim 24 (depends on 23) The control system according to claim 23 further comprising a filter arranged to filter out a range of frequencies to perform the filtering, wherein the control system is arranged to operate in the high speed mode when the fundamental frequency is within a range which will be filtered out by the filter and to operate in the low speed mode at lower speeds when the fundamental frequency is not within the range. ### Claim 25 (depends on 21) The control system according to claim 21 wherein the correction means is arranged to combine the correction signal with the voltage demand to produce a corrected voltage demand. ### Claim 26 (depends on 16) The control system according to claim 16 for an electric motor having stationary windings and a rotor which rotates relative to the windings, wherein the current sensing means includes a current sensor arranged to measure current in the motor windings and a transformation means arranged to transform the measured current into the frame of reference of the rotor. ### Claim 27 (depends on 21) The control system according to claim 21 wherein the current control means is arranged to output the voltage demand so as to define a demanded voltage in a frame of reference which is rotating. ### Claim 28 (depends on 16) The control system according to claim 16 that is arranged to correct a plurality of components of distortion. ### Claim 29 (depends on 28) The control system according to claim 28 wherein the components of distortion are harmonics having different frequencies and/or different signs.