# US 2018/0322231 A1 · Interior magnet machine design with low core losses > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0322231 A1 - Document ID: US20180322231A1 - Status: Published application - Kind: A1 - Application number: 15/772,041 - Filed: 2016-10-27 - Published: 2018-11-08 - Earliest claimed: 2015-10-30 - Assignees: Faraday & Future Inc. - Applicants: Faraday&Future Inc. - Inventors: Mengwei Li Campbell; Jie Dang - Web page: https://patentgrep.com/patent/US20180322231A1 ## CPC - G06F 30/23: using finite element methods [FEM] or finite difference methods [FDM] - G01R 31/34: Testing dynamo-electric machines - G01R 33/02: Measuring direction or magnitude of magnetic fields or magnetic flux (G01R33/20 takes precedence) - G06F 2119/18: Manufacturability analysis or optimisation for manufacturability - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) ## Abstract Methods and apparatus for estimating and minimizing core losses in interior magnet machines are disclosed. Methods can include creating, modifying, or receiving a finite element analysis (FEA) model to represent at least one portion of an motor in a computer system, placing at least one coil at a first location within the rotor iron or stator iron of the motor in the FEA model, calculating a time-domain flux density B of the at least one coil, converting the calculated flux density function to a frequency-domain spectrum, receiving material core loss parameters for at least some frequencies indicated by the frequency-domain spectrum, and determining a core loss of the at least one portion of an electric motor by a weighted combination of the material core loss parameters. Coils may be placed manually by a user through a user interface, or may be placed automatically. ## Claims ### Claim 1 A method of estimating core loss in an electric motor using a finite element analysis (FEA) simulation, comprising the acts of: creating, modifying, or receiving a FEA model to represent at least one portion of an electric motor in a computer system, the computer system comprising a user interface and a processing circuit configured for FEA simulations, the electric motor comprising at least one rotor capable of rotation about a rotational axis and a stator having at least one pole pair disposed radially about the rotational axis of the rotor; placing, with the user interface, at least one coil at a first location around at least one portion of the rotor iron or stator iron of the motor in the FEA model, the coil comprising a wire loop; calculating a time-domain flux density B of the at least one coil as a function of time; converting the calculated flux density function to a frequency-domain spectrum; receiving material core loss parameters for at least some frequencies indicated by the frequency-domain spectrum; and determining a core loss of the at least one portion of an electric motor by a weighted combination of the received material core loss parameters according to the relative magnitudes of the peaks in the discrete frequency-domain spectrum. ### Claim 2 (depends on 1) The method of claim 1, further comprising the act of modifying, adjusting, or redesigning a FEA model based on the estimated core loss so as to minimize core loss. ### Claim 3 (depends on 2) The method of claim 2, further comprising manufacturing an electric motor based on the modified, adjusted, or redesigned FEA model. ### Claim 4 (depends on 1) The method of claim 1, wherein the at least one portion of an electric motor comprises at least one portion of the at least one rotor and at least one portion of the stator. ### Claim 5 (depends on 1) The method of claim 1, further comprising executing a time-stepped FEA simulation of the FEA model. ### Claim 6 (depends on 1) The method of claim 1, further comprising receiving an output from the processing circuit configured for FEA simulations, the output comprising a flux linkage or flux density of the at least one coil as a function of time. ### Claim 7 (depends on 1) The method of claim 1, wherein converting the calculated flux density function to a frequency-domain spectrum comprises computing a discrete Fourier transform (DFT) of the time-domain flux density function. ### Claim 8 (depends on 1) The method of claim 1, wherein the material core loss parameters comprise B-P curves. ### Claim 9 An apparatus for estimating core loss in an electric motor using a finite element analysis (FEA) simulation, the apparatus comprising: means for creating, modifying, or receiving a FEA model to represent at least one portion of an electric motor in a computer system, the computer system comprising a user interface and a processing circuit configured for FEA simulations, the electric motor comprising at least one rotor capable of rotation about a rotational axis and a stator having at least one pole pair disposed radially about the rotational axis of the rotor; means for placing at least one coil at a first location within the rotor iron or stator iron of the motor in the FEA model, the coil comprising a wire loop; means for calculating a time-domain flux density B of the at least one coil as a function of time; means for converting the calculated flux density function to a frequency-domain spectrum; means for receiving material core loss parameters for at least some frequencies indicated by the frequency-domain spectrum; and means for determining a core loss of the at least one portion of an electric motor by a weighted combination of the received material core loss parameters according to the relative magnitudes of the peaks in the discrete frequency-domain spectrum. ### Claim 10 (depends on 9) The apparatus of claim 9, wherein the at least one portion of an electric motor comprises at least one portion of the at least one rotor and at least one portion of the stator. ### Claim 11 (depends on 9) The apparatus of claim 9, further comprising means for executing a time-stepped FEA simulation of the FEA model. ### Claim 12 (depends on 9) The apparatus of claim 9, further comprising means for receiving an output from the processing circuit configured for FEA simulations, the output comprising a flux linkage or flux density of the at least one trivial coil as a function of time. ### Claim 13 (depends on 9) The apparatus of claim 9, wherein converting the calculated flux density function to a frequency-domain spectrum comprises computing a discrete Fourier transform (DFT) of the time-domain flux density function. ### Claim 14 (depends on 9) The apparatus of claim 9, wherein the material core loss parameters comprise B-P curves. ### Claim 15 A computer program product for processing data for a program configured to estimate core loss in an electric motor using a finite element analysis (FEA) simulation, the computer program product comprising: a non-transitory computer-readable medium having stored thereon code for causing processing circuitry to: enable a user to create, modify, or receive a FEA model to represent at least one portion of an electric motor in a computer system, the computer system comprising a user interface and a processing circuit configured for FEA simulations, the electric motor comprising at least one rotor capable of rotation about a rotational axis and a stator having at least one pole pair disposed radially about the rotational axis of the rotor; enable placement, with the user interface, of at least one coil at a first location within the rotor iron or stator iron of the motor in the FEA model, the coil comprising a wire loop; calculate a time-domain flux density B of the at least one coil as a function of time; convert the calculated flux density function to a frequency-domain spectrum; receive material core loss parameters for at least some frequencies indicated by the frequency-domain spectrum; and determine a core loss of the at least one portion of an electric motor by a weighted combination of the received material core loss parameters according to the relative magnitudes of the peaks in the discrete frequency-domain spectrum. ### Claim 16 (depends on 15) The computer program product of claim 15, wherein the at least one portion of an electric motor comprises at least one portion of the at least one rotor and at least one portion of the stator. ### Claim 17 (depends on 15) The computer program product of claim 15, wherein the code stored on the non-transitory computer-readable medium further causes processing circuitry to execute a time-stepped FEA simulation of the FEA model. ### Claim 18 (depends on 15) The computer program product of claim 15, wherein the code stored on the non-transitory computer-readable medium further causes processing circuitry to receive an output from the processing circuit configured for FEA simulations, the output comprising a flux linkage or flux density of the at least one trivial coil as a function of time. ### Claim 19 (depends on 15) The computer program product of claim 15, wherein the code for causing processing circuitry to convert the calculated flux density function to a frequency-domain spectrum comprises code for causing processing circuitry to compute a discrete Fourier transform (DFT) of the time-domain flux density function. ### Claim 20 (depends on 15) The computer program product of claim 15, wherein the material core loss parameters comprise B-P curves.