A simplified approach to permanent magnet and reluctance motor characteristics determination by finite-element methods
Purpose - To provide a new method for the determination of motor characteristics by means of FE-methods suitable for multi-variable design processes. Design/methodology/approach - The process is based on two-dimensional, steady state and frequency domain FE-analysis including a stepwise movement of the rotor. The process consists of the following steps: generation of an appropriate FE-model with specific mesh generation; input of the machines parameters and the parameters of the simulation process; no load simulation: cogging torque T, no load fluxes Psi(mo)and voltages u(0) and the phase angles of the windings currents; load simulation with given currents: average and the pulsating torque T, fluxes Psi(l)(alpha), voltages U, two-axis model parameters Psi(m), L-d and L-q; determination of operating characteristics: torque T, voltage U, current I, power P, angles beta and delta Cos phi, as functions of speed n. Based on machine parameters from step 3 and 4 determination of losses in the magnets by means of a frequency domain model and the fluxes in the magnet from steps 3 and 4. Findings - Special attention has to be given to the mesh design. The mesh configuration should be kept constant during the movement. Motor parameters are determined for one operating point. The process is very fast and accurate enough (< errors) for design purposes. Practical implications - It is shown how FE-methods can be used in motor design, avoiding time-consuming transient simulations. Originality/value - It is a new and very efficient FE-process for motor design.
finite element analysis magnetic measurement electric motors