Method for driving an ultrasonic system to improve acquisition of blade resonance frequency at startup

摘要

The ability of an ultrasonic system to sweep and lock onto a resonance frequency of a blade subjected to a heavy load at startup is improved by applying a high drive voltage or a high drive current while systematically increasing the level of the applied signal. Increasing the drive signal to the hand piece results in an improved and more pronounced "impedance spectrum." That is, under load, the increased drive signal causes the maximum phase margin to become higher and the minimum/maximum impedance magnitude to become more pronounced. Increasing the excitation drive signal to the hand piece/blade at startup significantly alleviates the limiting factors associated with ultrasonic generators, which results in an increase of the maximum load capability at startup.