INTERIOR MAGNET MACHINE DESIGN WITH LOW CORE LOSSES
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.
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.
2 . 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.
3 . The method of claim 2 , further comprising manufacturing an electric motor based on the modified, adjusted, or redesigned FEA model.
4 . 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.
5 . The method of claim 1 , further comprising executing a time-stepped FEA simulation of the FEA model.
6 . 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.
7 . 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.
8 . The method of claim 1 , wherein the material core loss parameters comprise B-P curves.
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.
10 . 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.
11 . The apparatus of claim 9 , further comprising means for executing a time-stepped FEA simulation of the FEA model.
12 . 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.
13 . 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.
14 . The apparatus of claim 9 , wherein the material core loss parameters comprise B-P curves.
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.
16 . 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.
17 . 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.
18 . 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.
19 . 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.
20 . The computer program product of claim 15 , wherein the material core loss parameters comprise B-P curves.