Distributed-Parameter Modeling of High-Power Giant Magnetostrictive Transducers Considering Permanent Magnetic Bias

High-power giant magnetostrictive transducers (GMTs) with stacked-disk permanent magnet (PM) bias are widely used in industrial drive and underwater acoustics. Because they generally use large-size giant magnetostrictive rod (GMR), stacked-disk PM bias will cause uneven distribution of the magnetomechanical field in GMR and further exacerbate the nonlinearity of the dynamic output of GMT. However, most existing models rarely consider this distributed-parameter characteristic in GMT. Therefore, it is necessary to develop a model that can simulate uneven magnetomechanical coupling characteristics and dynamic behaviors of high-power GMTs. In this article, a dynamic distributed-parameter model (DPM) of high-power GMT with PM bias is developed, which thoroughly considers magnetic uneven spatial distribution, magnetic hysteresis, and mechanical behavior under multiple excitations. This model includes a nonlinear high-precision magnetic equivalent circuit (HP-MEC), an improved J–A model considering bias magnetic field, and a mechanical model. First, model errors of DPM under different numbers of microelements were compared to determine a suitable division in GMR. Second, to verify the proposed model, the responses of DPM and lumped parameter model (LPM) with different PM thickness and ac frequencies were compared, and the experimental results verified the superiority of DPM. In addition, in the discussion section, DPM was used to analyze the uneven distribution of magnetic field and the distribution characteristics of dynamic output in GMT. Finally, the application of DPM in the optimal working configuration of high-power GMT is discussed.