Study on Eddy Currents Losses in Transducers Using Terfenol-D

One of the major problems in the transducers using Terfenol-D is the power losses arising from eddy currents induced in the Terfenol-D due to variations of the magnetic field with time. This article presents an analytical model for eddy currents losses of these devices. To this end, a mathematical model based on Maxwell’s equations is developed and inside magnetic field of Terfenol-D, eddy currents density and ratio of its losses to input power are obtained. Results show that eddy currents and the relevant losses are highly dependent on operational frequency and material conductivity. Increasing the frequency leads to reduce the inside magnetic field and grow the eddy currents losses. However, the ratio of these losses to input power increases rapidly up to a specific frequency and then decreases slightly. In addition, variation of conductivity may increase or decrease the eddy currents losses depending on the operational frequency.

Keywords:

Magnetostriction effect , Terfenol-D transducers , eddy currents losses , Maxwell’s equations , Bessel function of order zero