Research Of The Electromagnetic Ultrasonic Pulser

Electromagnetic ultrasonic pulser is a kind of high power ultrasonic pulse output device,which has many advantages,such as non-contact,no coupling medium and high resolution.It is widely used in medical and industrial fields.The highest pressure and reliability coefficient have been obtained in this generator which use the shock action of strong pulsed magnetic fields of microsecond duration on the spherical surface foil spherical.The device can be applied in medical facilities for destruction of kidney stones and gallstones.However,control over the duration of acoustic pulses in this radiator is impeded,because their exciting coils have fixed numbers of turns,and the pulse duration can be varied only by changing the capacitance of the discharge circuit.Therefore,traditional device has defects in both application and conversion efficiency.The performance of domestic electromagnetic pulse generator still has large gap compared with international advanced products,so it is very important to study the electromagnetic pulse generator.This paper combined the disciplines of electromagnetics and ultrasound with multi-physics correlation theory,and designed a new ultrasonic pulse generators with low cost,simple structure,high output power and continuous sound pulse with different duration based on the existing designation and structural.The paper is composed as follow parts:1.The first part of this paper is beginning with the background research of the subject,analyzing the current situation of related topics at home and abroad,and contributing to the significance and necessity of the research.2.The research of this subject belongs to interdisciplinary,involving many subjects including electromagnetism and ultrasonics,so this part mainly introducing the relative theory.3.This part contains the design of hardware circuit system,the circuit system consists of three parts: energy storage capacitor charging circuit,the excitation coil discharge circuit and the pulse selection control circuit.The excitation coil structure in a charge-discharge system is designed as a plurality of output terminals to produce two or more interval-controlled continuous acoustic pulse with different durations.4.In this part,we use COMSOL Multiphysics to simulate the transducer and analyze the vibration of the membrane.The foil displacement and the coil excitation current can be inferred by electromagnetic response and amplitude response of the foil.The optimal point of the transducer foil deformation is discussed and the concept of the best point of foil deformation is proposed in this part.This design can effectively improve the existing acoustic pulse generator which has disadvantages of flexibility and efficiency,and provide a significant research method for the development of medical equipment,acoustic cavitation and other relative areas.