NISA Software - Magnetic Field Analysis

Magnetic Field Analysis

Analysis of the magnetic field produced by the steady current sources, permanent magnets or time varying current sources and specified boundary conditions. For the case with static sources, either scalar or vector Poisson's equation govern the field. With the time varying sources/boundary conditions, eddy current phenomena prevail and hence the eddy current equation need to be considered. The material nonlinearity play a significant role in governing the magnetic field distributions.

Three distinct categories of the magnetic field analysis are:

Magnetostatic analysis
Magnetodynamic analysis
Transient Magnetic field analysis

Magnetostatic Analysis:

Magnetic field produced by steady currents and/or permanent magnets. Magnetic material properties are in general nonlinear and can be orthotropic.

Following types of analysis are provided:

2D planar and axisymmetric Magnetostatic analysis using vector potential approach (MGSV) - For the 2D problems, vector potential has either z-component (2D planar) or -component (Axisymmetric) only.
3D Magnetostatic analysis using reduced scalar potential approach (MGSS) By employing a reduced scalar potential with Biot-Savart's law, significant reduction in the computational time is achieved. However, nonlinearity and permanent magnets are not included.
3D Magnetostatic anslysis using the magnetic vector potential approach (MGVP) Use of fully magnetic vector potential approach yields accurate results as compared with reduced scalar potential approach.

Inputs:

Linear or nonlinear, isotropic or anisotropic material properties: Magnetic permabilities or reluctivities of the participating media. B-H curve for the nonlinear materials. Specifications of the linear or nonlinear permanent magnets if any.
Specified current density distributions in the media and specified vector/reduced scalar potentials at the boundaries
Specified flux flow along the problem boundaries, if any
Flux tangential boundaries
Specification of the “open boundary” if any in the problem through infinite elements
Specification of the moving object for force/torque calculations

Outputs:

Vector/reduced scalar potential distribution
Magnetic field intensity and Magnetic flux density distributions
Stored magnetic energy and coenergy for each element
Total stored magnetic energy and coenergy
Inductance
Force or Torque on the moving object

For the post processing, potential, magnetic field intensity and magnetic flux densities are available.

Typical problems that can be analysed using these analysis types are:

Solenoids & lift magnets
Transmission lines
Transformers
DC & AC rotating electrical machinery
Circuit breakers
Relays

Magnetodynamic Analysis

Magnetic field produced by steadystate sinusoidally varying currents with only linear materials in the problem.

Inputs:

Linear isotropic material properties: Magnetic reluctivities of the participating media. Conductivities for the massive conductors i.e. where the eddy currents are expected to be significant.
Specified current density distributions with their phases in the media and specified vector potentials at the boundaries
Flux tangential boundaries
Specification of the “open boundary” if any in the problem through infinite elements

Outputs:

Magnetic vector potential distribution
Magnetic field intensity and Magnetic flux density distributions
Eddy current density distribution
Total current density distribution
Induced electric field distribution
Total electric field distribution
Power loss density distribution
Stored magnetic energy for each element
Total stored magnetic energy
Total power loss
Inductance
Resistance

For the post processing, magnetic vector potential, magnetic field intensity and magnetic flux densities, eddy current density, induced electric field, total current density and total electric field are available. Results are also available for different instants or angles. With the elegant movie option of the DISPLAY III, results corresponding to different instants can be viewed in dynamic mode.

Typical problems that can be analysed using this analysis type are:

Solenoids & lift magnets
Transmission lines and Bus bars
Transformers
Induction machines
Synchronous machines

Transient Magnetic Field Analysis

Magnetic field produced by arbitrarily time varying currents and steady permanent Magnets. Materials involved in general can be nonlinear.

Inputs:

Linear or nonlinear material properties: Magnetic reluctivities of the participating media. B-H curve specification for the nonlinear materials.
Specifications of the linear or nonlinear permanent magnets, if any. Specify conductivities for the massive conductors i.e. for the conducting regions where the eddy currents are expected to be significant
Specified current density distributions and their time variations and specified vector potentials at the boundaries
Flux tangential boundaries
Specification of the “open boundary” if any in the problem through infinite elements

Outputs:

Magnetic vector potential distribution
Magnetic field intensity and Magnetic flux density distributions
Eddy current density distribution
Induced electric field distribution
Power loss density distribution
Stored magnetic energy and coenergy for each element
Total stored magnetic energy

For the post processing, magnetic vector potential, magnetic field intensity and magnetic flux densities are available. Results are also available for different time Instants. With the elegant movie option of the DISPLAY III, results corresponding to different instants can be viewed in dynamic mode.

Typical problems that can be analysed using this analysis type are: