# US 10,483,894 B2 · 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 10,483,894 B2 - Document ID: US10483894B2 - Status: Granted - Kind: B2 - Application number: 14/123,622 - Filed: 2012-05-16 - Published: 2014-07-10 - Granted: 2019-11-19 - Earliest claimed: 2011-06-03 - Assignees: TRW Inc. - Applicants: Christoper David Dixon - Inventors: Christoper David Dixon - Web page: https://patentgrep.com/patent/US10483894B2 ## 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 1 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; a current controller arranged to receive a current demand and to control voltages applied to the electric motor; and a harmonic compensation controller arranged to operate in both (1) a high speed mode of operation of the motor, wherein the harmonic compensation controller identifies a distortion frequency and at least partially isolates a distortion frequency component from a fundamental frequency component of the current sensing output by filtering, and (2) a low speed mode of operation of the motor, wherein the harmonic compensation controller receives the current sensing output and the current demand as separate inputs and uses the separate current sensing output and the current demand inputs to generate a correction signal, wherein the current controller is arranged to receive and use the correction signal to correct voltages applied to the electric motor. ### Claim 2 (depends on 1) The control system according to claim 1 wherein the harmonic compensation controller is arranged 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 3 (depends on 2) The control system according to claim 2 wherein the correction signal is arranged to indicate a magnitude of the distortion frequency component. ### Claim 4 (depends on 2) The control system according to claim 2 wherein the harmonic compensation controller 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 5 (depends on 1) The control system according to claim 1 wherein the harmonic compensation controller is arranged to generate a distortion signal from the current sensing output and the current demand. ### Claim 6 (depends on 1) The control system according to claim 1 wherein the harmonic compensation controller 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 the fundamental frequency component of the current in the electric motor. ### Claim 7 (depends on 1) The control system according to claim 1 wherein the current controller 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 8 (depends on 7) The control system according to claim 7 wherein the harmonic compensation controller is arranged to combine the correction signal with the voltage demand to produce a corrected voltage demand. ### Claim 9 (depends on 7) The control system according to claim 7 wherein the current controller is arranged to output the voltage demand so as to define a demanded voltage in a frame of reference which is rotating. ### Claim 10 (depends on 1) The control system according to claim 1 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 11 (depends on 1) The control system according to claim 1 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 12 (depends on 1) The control system according to claim 1 that is arranged to correct a plurality of components of distortion. ### Claim 13 (depends on 12) The control system according to claim 12 wherein the components of distortion are harmonics having different frequencies and/or different signs. ### Claim 14 A combined control system and electric motor assembly comprising: an electric motor; and a control system including: (1) a current sensor that produces a current sensing output signal that is indicative of an electric current in the electric motor; (2) a current controller that receives a current demand signal and controls voltages applied to the electric motor; and (3) a correction circuit that operates in both (a) a high speed mode of operation of the electric motor, wherein the correction circuit identifies a distortion frequency and at least partially isolates a distortion frequency component from a fundamental frequency component of the current sensing output signal by filtering, and (b) a low speed mode of operation of the electric motor, wherein the correction circuit receives the current sensing output signal and the current demand signal as separate inputs and uses the separate current sensing output and the current demand inputs to generate a correction signal to the current controller, which uses the correction signal to correct voltages applied to the electric motor. ### Claim 15 (depends on 14) The combined control system and electric motor assembly according to claim 14 wherein the correction circuit determines, from the current sensing output signal and the current demand signal, a component of the current in the electric motor at the distortion frequency. ### Claim 16 (depends on 14) The combined control system and electric motor assembly according to claim 14 wherein the correction circuit generates a distortion signal from the current sensing output signal and the current demand signal. ### Claim 17 (depends on 14) The combined control system and electric motor assembly according to claim 14 wherein the correction circuit performs a comparison between at least a component of the current sensing output signal and at least a component of the current demand signal to at least partially isolate the distortion frequency component from the fundamental frequency component of the current in the electric motor. ### Claim 18 (depends on 14) The combined control system and electric motor assembly according to claim 14 wherein the current controller outputs a voltage demand signal that is indicative of voltages to be applied to the electric motor, and wherein the correction signal is indicates corrections to the voltage demand signal. ### Claim 19 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; a current controller arranged to receive a current demand and to control voltages applied to the electric motor; and a harmonic compensation controller arranged to operate in both (1) a high speed mode of operation of the motor, wherein the harmonic compensation controller identifies a distortion frequency and at least partially isolates a distortion frequency component from a fundamental frequency component of the current sensing output by filtering, and (2) a low speed mode of operation of the motor, wherein the harmonic compensation controller receives the current sensing output and the current demand as separate inputs and uses the separate current sensing output and the current demand inputs to generate a correction signal, wherein the current controller is arranged to receive and use the correction signal to correct voltages applied to the electric motor. ### Claim 20 (depends on 19) The control system according to claim 19 wherein the harmonic compensation controller is arranged 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 21 (depends on 20) The control system according to claim 20 wherein the correction signal is arranged to indicate a magnitude of the distortion frequency component.