Application of Static and Dynamic Magnetic Finite Element Analysis to the Design and Optimization of Moving Coil Transducer Motors

摘要

Transducer motors are potential source of nonlinear distortion. There are several nonlinear mechanisms that generate nonlinear distortion in motors. Typical loudspeaker nonlinear models include the dependence of the Bl-product and the voice coil inductance L_(vc) on the voice coil position and current. These effects cause nonlinearity in the driving force, electrodynamic damping, and generate nonlinear flux modulation and reluctance force. In reality, the voice coil inductance and resistive losses depend also on frequency. To take these effects into account the so-called LR-2 impedance model is used. The L_2 and R_2 elements are nonlinear functions of the voice coil position and current. In this work detailed analysis of a nonlinear model incorporating these elements is performed. The developed approach is illustrated by the FEA-based design and optimization of a new JBL ultra-linear transducer to be used in a new line array system.