MASTA Modules

Electric Machine Hairpin Windings

Automotive traction motors are increasingly making use of hairpin winding technology.

In MASTA 13 users will be able to choose to implement hairpin windings as an alternative to the already available random round windings option.

In Electric Machines mode, a new property Winding Type has been added. This allows to select between Round Conductors and a Hairpin winding.

With Hairpin selected, the number of layers and desired number of parallel paths can be selected and MASTA’s automated winding algorithm will produce hairpin windings designs with strong symmetry where possible.

The user is free to customize this configuration. MASTA will prevent non-viable designs from being implemented and will warn the user if their winding exhibits weak symmetry.

Analysis can be performed either using current sheets within the slot regions or by specifying details of the individual conductors.

If details of individual conductors are included a detailed calculation of the AC winding losses may be performed within the FE based analysis.

These Conductor Details Are:

Winding Material Width
Winding Material Length
Corner Radius
Radial Offset
Radius
Angular Offset
Conductor Dimension For DQ Model

If individual conductors are specified, AC winding losses may also be included in the generation of a Non-Linear DQ Model.

With AC Winding Losses included in the DQ model they will be included in any efficiency maps calculated using the DQ model.

Within the charts available for the Efficiency Map Analysis an additional chart has been added to allow to view the AC Winding Losses.

Get in touch with us today for more information.

NVH Operating Maps

When running Harmonic Analysis, MASTA uses a System Deflection analysis to calculate a stiffness model of the design, using the torque, speed and power configuration from the load case.

This model is then used to obtain dynamic response results at a range of speeds. Whilst effective, this approach assumes that the design’s stiffness does not vary significantly across the speed range of interest.

SMT have developed a method where torque slices can be used to represent the full range of speeds for the transmission. This is particularly important in typical EV applications where gears operate throughout large speed and torque ranges.

There Are 3 Methods To Select The Torque Inputs For Harmonic Analysis:

Load Case: Will run a single torque point
Specified Torque Speed Curve: User defined points for the curve
Torque Speed Curve from Electric Machine Harmonic Load Data: Automatically generated torque speed data from the imported electric machine

There are multiple options for defining the torque splits from Torque Speed curve, either automatically or manually.

For each step MASTA will run a full harmonic analysis.

With the extended information processed in this calculation, there are new charts available to view the results.

The waterfall chart for all of the excitations can be viewed with the boundaries of the torque steps.

The order cuts for each torque level at the respective speed can be combined to show the full speed range.

In addition to this, the changing respective excitation value can be seem simultaneously in the same window.

A new chart type ‘Torque Map’ is available in the Harmonic Analysis results.

This will show the response of a selected harmonic across the whole speed and torque range that has been specified.

NVH Operating Maps is available as a new module with code MA128.

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High Speed Ball Bearing Analysis (Dynamic)

Adding to the high-fidelity quasi-static high speed bearing model introduced in MASTA 12, MASTA 13 extends this method to a dynamic 6 degree of freedom model per ball for ball bearings as a new module MA129 – High Speed Ball Bearing Analysis (Dynamic).

This Dynamic Model Includes The Following Forces On The Ball:

Friction from sliding (integration over contact ellipses)
Hydrodynamic rolling and pressure forces
Elastic rolling resistance moment
Viscous drag
Centrifugal force
Gyroscopic moment
Contact normal forces
Ball-cage impact forces and frictional moment due to sliding

In addition to this, a 3 degree of freedom cage model is introduced, removing the need for raceway control.

Forces Considered On The Cage Include:

Ball-cage impact forces and frictional force from sliding at the contact
Cage-ring impact forces and frictional force from sliding at the contact
Gravity

Ball bearings now have several more options to describe their geometry that are used in the dynamic analysis.

The cage bridge shape can be flat or curved.

This affects the stiffness of the ball-cage contact.

This high-fidelity dynamic analysis includes an advanced visco-plastic plus asperity effect lubricant friction model that can be used to accurately predict power losses in ball bearings.

The risk of smearing can be calculated with this model better than using a quasi-static model since the ball will precess around the entire ring.

Furthermore, smearing is inherently a dynamic phenomenon and hence is more suited to being analysed in a dynamic model.

After running System Deflection analysis, there is a new Dynamic Bearing Results tab where the detailed dynamic bearing analysis results can be calculated and the results chart viewed.

The model in this new module has been published in the following paper:

L. Houpert, C. Penny & J. Clarke (2023) Bearing models for advanced ball bearing simulation, Tribology Transactions, DOI: 10.1080/10402004.2023.2240063

L. Houpert, J. Clarke & C. Penny (2023) Tribological Models for Advanced Ball Bearing Simulation, Tribology Transactions, DOI: 10.1080/10402004.2023.2213470

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System Optimiser

System Optimiser has been remodelled in MASTA 13 and has improvements to the optimisation results as well as additional capabilities.

Users give a basic layout and power flow configuration for their design; System Optimiser will then search through the defined limits on tooth numbers to find the correct ratios.

System Optimiser uses macro geometry optimisation to find potential gear set designs and selects the combination of gear set designs that meet the specified criteria whilst also satisfying requirements for strength, packaging, and contact ratio.

Now taking its own place in the MASTA mode ribbon, System Optimiser is now capable of delivering design candidates for complex planetary arrangements, including the number of planets.

In an environment where noise has become a major design consideration, System Optimiser has the option to avoid creating gear sets with overlapping orders and can target contact ratios.

Keeping in tune with MASTA’s convenient workflow, gearset candidates can be added to the Macro Geometry design list as well as creating configurations which can be easily transported to other modes and the MASTA Parametric Study tool.

These designs and configurations can also be accessed from the MASTA API to be integrated in users’ own proprietary optimisation and automation tools.

System Optimiser is available as module code MO104.