To acquire approved ultrasonic emulsification effects while using the power ultrasonic medical treatment instrument to cure patients

an ultrasonic vibration system is always needed to operate at a high vibration amplitude under different load conditions and to work in the electormechanical matching state under all load conditions. Firstly

the paper focuses on the equivalent electromechanical model to the power ultrasonic vibration system made up of a longitudinal composite-bar high-power transducer

a horn and a scalpel. Secondly

depending on the model

it analyzes the fundamental principles of dynamic impendence matching in the power ultrasonic vibration system. At the same time

according to the operating characteristics of the system

an approach to dynamic impedance on-line detecting has been devised and the parameters reflecting load state and change trend are obtained. Based on the identified dynamic load

the input and output parameters of the fuzzy controller can be determined.Finally

it presents an applied fuzzy control algorithm

which can be used as a dynamic impedance matching approach for the power ultrasonic vibration system. The experiment results show that when the power ultrasonic vibration system operates at the state of dynamic impedance matching by using the fuzzy control technique

the system can always have high electric power and good effects of the ultrasonic emulsification under the changing load.