Computer-aided optimization of rare-earth permanent magnet actuators

The application of high energy permanent magnets such as NdFeB and PrFeB, offers the potential for increasing the power/weight capability of many forms of limited motion actuator. The authors describe a CAD package which offers two approaches to optimization, the first of which involves the scanning of the `design space´ by incrementing one or more of the leading design parameters within a pre-specified range, whilst the second employs a penalty function constrained optimization method to minimize an application specific objective function. Both use nonlinear reluctance networks to model the actuator whose design is to be synthesized. Two case studies are presented to demonstrate the utility of the package, the first of which is concerned with the design of a limited angle torque motor for maximum torque/amp and torque/inertia whilst the second is a short-stroke linear voice-coil actuator optimized for minimum copper loss, both being validated experimentally