Optimal design and prototyping of a five-phase direct-drive permanent magnet linear motor

Abstract

An efficient analytical approach is proposed for design of fault-tolerant five-phase permanent-magnet direct-drive linear motor drives for reliability-critical applications. The proposed approach is based on shaping back EMF waveform through a simple closed-from analytical equation to achieve optimal design using a genetic algorithm based optimization. Magnet track and coil assembly parameters are optimized to have a sinusoidal back EMF waveform. Mathematical derivation of optimal fault-tolerant currents for ripple-free operation under open-circuit faults is presented. Proposed methodology can be used to design actuators for high-precision safety-critical applications. Finite-element-analysis and experimental test results are used to verify proposed design method.