Motor-CAD’s EMag module combines a 2D transient finite element-based approach with analytical methods for different electric machines to rapidly calculate their electromagnetic performance. EMag is used to calculate torque, power, efficiency, torque ripple, losses, currents, flux linkages, inductances, and forces. It can also calculate losses, including copper loss, iron losses, frequency-related losses in the winding and eddy current losses in solid components such as the magnet and shaft. Motor-CAD’s template-based editor makes it easy to set up geometries and do advanced calculations quickly and easily. Motor-CAD is flexible allowing users to experiment with different options such as custom winding patterns or import their own geometry from a DXF. Some key features of EMag are listed here:
- An extensive range of parametrized templates and geometries
- Automated calculation setup for different performance tests
- Automated configuration of built-in 2D transient or magneto-static FEA solvers with meshing and boundary conditions
- Advanced calculation capabilities, such as eddy current in magnets, induction machine rotor bars and calculation of AC winding losses
- DXF and scriptable geometries, custom current waveforms and multi-slice rotor skewing
- A combined 2D finite element and analytical modeling approach so designs can be input and calculated in minutes, enabling you to account for complex electromagnetic effects early in the design process
- Coupling to Motor-CAD Therm, enabling you to solve thermal calculations iteratively
- Calculation of torque, power, losses, voltages, currents, inductances, flux linkages and forces
- Linkage to Maxwell for detailed FEA analysis
Motor-CAD’s Therm module calculates the thermal performance of electric machines in seconds, including the temperature of the motor components in steady-state and transient operating conditions. Expedited simulations in Motor-CAD are extremely beneficial when modeling complex duty cycles such as traction motor drive cycles and applications such as elevator load cycles.
Motor-CAD uses an analytical lumped parameter thermal modeling technique which is automatically set up based on the user’s inputs such as geometry, materials, cooling type etc. From these inputs, all the thermal resistances and capacitances are automatically calculated. No knowledge of complex heat transfer phenomena — such as dimensionless analysis correlations for convection — is needed. The lumped-circuit technique accelerates thermal analysis and allows what-if tests in real time. A good understanding of the main heat transfer paths allows engineers to optimize the machine’s cooling behavior.
The thermal resistance network that is automatically set up is three-dimensional, enabling a 3D analysis of cooling in the end space, cooling of the end windings, effects of rotation on the air flow and heat transfer in the axial direction of the machine.
Many cooling types are supported:
- Natural convection (TENV)
- Forced convection (TEFC)
- Through ventilation
- Water jackets (several configurations)
- Wet rotor and wet stator
- Spray cooling
Motor-CAD automatically selects and solves the most appropriate formulation for a given surface and the cooling type selected. It calculates forced and natural convection, liquid cooling, radiation and conduction. It uses an extensive library of proven laminar and turbulent convection correlations to give accurate models for all internal and external surfaces. The airgap model includes laminar, vortex and turbulent convection. These insights significantly improve a motor’s thermal performance, efficiency and output.
A major challenge concerning thermal management of electric machines is the number of manufacturing uncertainties and effects which often significantly impact machine performance. Some examples are the quality of the impregnation of the winding or the interface gap between the stator lamination and housing. Motor-CAD has built-in experience to guide users and engineers to input reasonable numbers here that give a good correlation with the majority of machines tested in labs.
Motor-CAD’s Lab module analyzes the machine performance over its full operating range. Users can rapidly create efficiency and loss maps, plot torque/speed characteristics, study the thermally constrained operating envelope and analyze performance over driving cycles.
The Lab module initially builds a model using the electromagnetic 2D finite element solver. It sweeps the performance of the machine through the full range of different current magnitudes, phase advance angles and frequencies to build an equivalent model of the machine. The equivalent model is used with a control strategy to calculate performance across the full operating range. Outputs such as efficiency maps, torque/speed curves and loss maps are rapidly generated. Users can input a time/torque/speed duty cycle or generate one using the built-in vehicle model. The Lab module calculates the currents, voltages and losses over this cycle and outputs a detailed loss vs time profile. This can be solved with the thermal model to calculate the temperature rise over the cycle. Users can also calculate thermally limited continuous torque/speed characteristics. A maximum winding temperature and maximum magnet temperature limit is input and the thermal model, control model and loss models are co-solved to compute the continuous torque/speed curve of the machine across the speed range.
Motor-CAD Mech provides a rapid estimation of the mechanical strain, stress and displacements induced in a rotor by the centrifugal forces. Ensuring structural integrity is a major challenge in high-speed rotating motors. The mechanical calculation uses a 2D linear finite-element solver with adaptive meshing. By considering the mechanical constraints during the design process, motor designers can size the rotor for optimal electromagnetic performance while ensuring industrial feasibility and safe operation over the full speed range of the machine.
Detailed Design, Analysis and Validation
For detailed design, deep analysis and validation of the motor design, the Motor-CAD model can be transferred to ANSYS Maxwell, ANSYS Icepak and ANSYS Fluent. Combining these solvers with Motor-CAD delivers high-fidelity, 2D/3D analysis capability, enabling you to analyze end-effects, demagnetization, core loss, hysteresis, noise-vibration-harshness (NVH) and other advanced electromagnetic phenomena necessary to design complete motor cooling systems. The addition of Motor-CAD to the ANSYS electric machine design flow creates a complete end-to-end workflow for electric machine design.
ANSYS Motor-CAD is available by specific motor type or in a comprehensive Enterprise license that includes all motor types.
Motor-CAD — motor-specific packages are available:
- Motor-CAD PM — Permanent magnet-based electric machines
- Motor-CAD IM — Asynchronous electric machines with an induced rotor field
- Motor-CAD SYNC — Synchronous electric machines
Motor-CAD Enterprise — Includes all motor types (PM, IM, SYNC)