Simulation in Manatee
Fast and accurate simulation models for multi-physics workflows
Simulation of Electric Machines in Manatee
Manatee software offers a suite of tools for fast and accurate e-NVH calculations. It includes fast electric circuit models for quick voltage-driven simulations and hybrid magnetic models for early design phase evaluations. The software integrates with FEA tools for detailed magnetic and structural analyses, supporting beam element and 3D FEA models. These models help engineers assess vibration and noise levels, optimize designs, and incorporate manufacturing tolerances like eccentricities and uneven magnetization. The platform facilitates collaboration among electrical, mechanical, and NVH engineers, enabling efficient and robust e-NVH simulations at concept and preliminary design phase.
Fast and Accurate e-NVH Calculations
- Fast Electric Circuit Models
- Fast Magnetic Models
- Finite elements magnetic models
- Beam Element Model
- Finite Elements Structural Models
- Fast Semi-Analytical Acoustic Models
Fast Electric Circuit Models
Manatee e-NVH software includes fast electrical circuit models to perform voltage-driven electromagnetic simulations. These models can be used to quickly estimate current levels from voltage inputs without transient simulations. They are based on harmonic Equivalent Electrical Circuits (EEC) in steady state, describing the voltage/current transfer functions with equivalent resistances and inductances.
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Fast EEC models can be used by electrical engineers to directly input the voltage control law. They are especially useful for induction machines (input of slip and phase voltage as a function of the operating point) and for the simulation of PWM voltage inverters.
Fast Magnetic Models
Besides proprietary algorithms to accelerate standard magnetic FEA simulations, Manatee e-NVH software also includes fast hybrid electromagnetic models to be used in the early design phase of electric machines. These hybrid magnetic models predicting the airgap flux distribution rely on the combination of permeance/magnetomotive force models, FEA computations, or magnetic reluctance models (for example to estimate saturation effects better). They can be used in current-driven or voltage-driven simulation workflows to quickly capture the main interactions between magnetic forces and structural modes, complementary to FEA magnetic models used in the intermediate or detailed design phase.
These fast magnetic models can be used by electrical engineers when ranking different e-machine topologies at the conceptual design phase (for example, comparing IPMSM to SCIM or different slot/pole combinations). As model parameters (for example, the number of harmonics and discretization) are automatically defined by Manatee, these fast models can also be easily run by mechanical or acoustic engineers to run a “what-if” scenario and get a qualitative idea of the design variables' influence on magnetic forces, vibration, and noise.
Finite Elements Magnetic Models
Manatee includes a coupling with the solver OPERA, in addition to the airgap flux import feature. Automated sliding bands, symmetries, and parallelization allow reducing the computing time of this nonlinear magnetostatic FEA. All magnetic models include proprietary algorithms to speed up the magnetic FEA simulations, which rely on Magnetic Look-up Tables (MLUT) combined with extrapolation/interpolation techniques. FEA-based MLUT can be used in current-driven or voltage-driven simulation workflows to accurately capture the interactions between magnetic forces and structural modes, complementary to fast magnetic models which can be used in early design phase.
These accurate magnetic models can be used by electrical or electromagnetic design engineers when iterating on the magnetic circuit geometry of the electric machine. Once magnetic forces have been characterized at different operating points inside a Magnetic Look-Up Table (MLUT), this MLUT can be loaded by mechanical engineers or NVH engineers to perform variable speed e-NVH calculations. When iterating on the structural design, this MLUT can be reused, accelerating mechanical design iterations for magnetic noise and vibration levels.
Beam Element Model
Manatee e-NVH software offers a rapid structural mechanics model for evaluating vibration levels under electromagnetic excitations, using the Beam Element Model for the stator yoke/tooth system. This model is particularly useful during the concept design phase of electric drives to avoid structural resonances and quickly assess stator vibration and noise levels. It is preferred for inner rotor machines as it accounts for stator tooth bending and the impact of radial and circumferential forces. Electrical and mechanical engineers can use this model to optimize the magnetic circuit and estimate natural frequencies. In the detailed design phase, calculations can be refined using Manatee's 3D modal basis import feature with a detailed CAD model.
Finite Elements Structural Models
Manatee e-NVH collaborative platform enables detailed calculations using a 3D FEA mechanical model of the electric drive, including components like the rotor, stator, housing, gearbox, driveline, and bearings. This detailed modeling provides more realistic modes compared to quick analytic or Beam Element models and is crucial for considering tolerances and faults in e-NVH calculations.
Manatee can import a modal basis from third-party 3D FEA software, such as SIMULIA Abaqus, and perform unique pre-processing to reduce e-NVH computation time. The imported modal basis can be reused in variable-speed simulations or parameter sweeps, as long as the magnetic circuit modifications do not alter it.
The 3D FEA model can include sensors to extract vibration levels in specific areas for comparison with accelerometer measurements or to assess nodal vibration in x, y, and z directions against NVH requirements. Mechanical engineers can import the 3D mechanical FEA modal basis, which can then be used by electrical engineers for electromagnetic model iterations or by NVH engineers for variable speed requirement checks.
Fast Semi-Analytical Acoustic Models
Manatee e-NVH software includes fast semi-analytical models of the acoustic radiation of electric machines, which can be used in different design phases.
In the early design phase, when no detailed CAD model is available, some semi-analytic radiation factor models of the external structure (stator or rotor) are proposed based on Equivalent cylinder shell models. In the detailed design phase, when Manatee uses a complex 3D FEA model, a fast way to evaluate the Sound Power Level is the analytic Equivalent Radiated Power (ERP) model.
Electrical engineers can use the equivalent cylindrical shell models in the early design phase to estimate the Sound Power Level radiated by the main in-plane flexural modes of the lamination winding assembly (or magnet steel assembly for external rotors). Mechanical and acoustic engineers can use the Equivalent Radiated Power model to estimate the sound level due to magnetic excitations.
Robust Design Including Manufacturing Tolerances
- Static and Dynamic Eccentricities
- Uneven Airgap
- Uneven Magnetization
3D Static and Dynamic Eccentricities
Manatee software evaluates the impact of 3D static and dynamic eccentricities' impact on electromagnetic noise and vibration levels due to mechanical tolerances. It allows for the specification of eccentricity levels and positions at both drive and non-drive ends.
For quick analysis, Manatee uses a perturbation technique to estimate parasitic magnetic forces caused by these eccentricities, suitable for low airgap deformations. This method can be applied with a Magnetic Look-Up Table or imported airgap flux from third-party software.
The perturbation technique helps estimate the effect of eccentricity on high-frequency magnetic force harmonics but may overestimate or underestimate certain components, such as the Unbalanced Magnetic Pull at H1. Mechanical and electrical engineers can use this feature to calculate the impact of 3D eccentricities, avoiding overly conservative mechanical tolerances and performing robust e-NVH ranking of different electrical machines. It is recommended to model eccentricity effects when using a 3D FEA mechanical model in Manatee to account for parasitic Unbalanced Magnetic Pull and its contributions to structure-borne and air-borne noise.
Uneven Airgap
Manatee software assesses the impact of uneven bore radius due to mechanical tolerances on electromagnetic noise and vibration levels. Users can specify patterns like elliptical deformation and their magnitude relative to the airgap width. For quick analysis, Manatee employs a perturbation technique on airgap flux density to estimate parasitic magnetic forces caused by 3D eccentricities. This method is effective for low airgap deformations (up to 15% of the airgap width) and can be used with a Magnetic Look-Up Table or imported airgap flux from third-party software.
The perturbation technique helps mechanical engineers evaluate the effects of uneven airgap on noise and vibrations, avoiding overly conservative mechanical tolerances. It also enables electrical engineers to perform robust e-NVH ranking of different machines, considering how stator deformations affect noise levels. Uneven airgap can result from manufacturing processes such as segmentation, welding, or shrink-fitting.
Uneven Magnetization
Manatee software allows you to assess the effect of uneven magnetization due to manufacturing or assembly tolerances on electromagnetic noise and vibration levels. A random perturbation can be set for all the magnets, or a user-defined variation can be set separately for each magnet of each pole.
Permanent magnet excitations might be uneven due to manufacturing variations, different operating temperatures, different positions in slots…
This feature allows electrical engineers to calculate the effect of uneven magnetization on electromagnetic noise and vibrations. Too conservative values of remanent flux tolerances can be avoided. Uneven magnetization may be specified using some magnetic field measurements outside the Permanent Magnet rotor.
This feature also allows electrical engineers to perform robust e-NVH ranking of different electrical machines. An electrical “machine A” may be louder than “machine B” without uneven magnetization, while it becomes the opposite with 2% of uneven magnetization.
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