Innovative electromagnetic design tool provides short route to motor perfection

Optimal design solutions to rotating electrical machine requirements can now be created in hours, by non specialists, using a new version of design automation software from Cobham Technical Services.

Cobham’s Machines introduced a new level of user friendliness when it was launched by providing a design entry system that allows precision finite-element analysis (FEA) models of motors and generators to be created and solved in minutes. The two-dimensional () version of the software has now been integrated with Cobham’s unique tool which automatically finds the optimal solution within a design space – even for multiple or competing design objectives.

Cobham’s Machines is an application-specific extension to the well known package. It provides a front-end to the simulator that speeds design entry by means of Wizard-style dialog boxes. Users select the style of or they want to design from a library of all common types, including induction, brushless permanent magnet and motors, and motors or generators. Then, dialog boxes allow the user to enter parameters to define mechanical geometry, material properties and electrical data, and the FEA model is automatically created.

The use of parameterized models and the ability to quickly load and modify previous designs has always made it possible for users to perform ‘what-if?’ design investigations. Now, to extend these possibilities to the maximum, Cobham has integrated a unique tool that makes it simple for users to find the best solution across the design space. While auto- tools are not new, they usually require manual intervention if the globally optimal solution is to be found, and the times involved often make this impractical. Cobham’s uniquely powerful tool – Optimizer – ‘intelligently’ selects and manages multiple goal-seeking algorithms including stochastic, descent, particle swarm and Kriging to eliminate the need for manual intervention.

Setting up an Optimizer run from the Machines has now been made as easy as the design entry process. Because most FEA simulations can take as little as a few seconds, the integrated software makes it feasible to thoroughly explore the design space. Thousands of simulations can typically be executed within hours, making the ‘perfect solution’ achievable for all users – without expert assistance.

“This software makes the high accuracy of finite element analysis available to all engineers, not just the expert with years of experience,” says Cobham’s Jeremy Howard-Knight. “Even a novice engineer can now create a precision finite element model and find the best solution in a design space, without needing to know much more than what he or she wants to achieve.”

The Machines Environment is now in its fourth generation, and Cobham has developed an extensive library of rotating machine design styles, and design components. However, if there are still any unusual features that need to be incorporated in designs, users also have open access to the scripts that generate the models, and can modify them at will to automate proprietary and design concepts. A library of common material properties is also included in the design software. Again, if users employ any special materials, such as an unusual grade of steel for laminations, then a new menu item can be created within minutes. Cobham will also generate custom scripts for users on request.

Cobham’s Machines Environment is expected to appeal to the many users of analytic design programs, giving a means of performing much more accurate analysis rapidly and without the engineering overhead usually required for accurate FEA. The tool can deliver significant advantages in today’s market environment. Currently, there’s enormous pressure to improve energy- for instance. The combination of highly accurate and sophisticated provides the means to identify the design characteristics of the perfect machine in very short timescales.

A three-dimensional version of the Machines Environment is optionally available.

Mesh and replications for a surface mounted permanent magnet machine

Automatic mesh generation using parameters available to the user for refinement.

Flux distribution in a permanent magnet external rotor machine

Optimal design solutions to rotating electrical machine requirements can now be created in hours, by non specialists, using the Machines Environment design automation software from Cobham Technical Services.