Abstract:

The main reason for the matching performance degradation caused by the output transformer mounted on the ultrasonic generator was analyzed. Then, based on the theory of the aircore transformer model, a novel primary serial matching scheme for the piezoelectric ultrasonic transducer was developed. This scheme eliminates the traditional matching inductor mounted on the secondary coil. If the total load, which is composed of the output transformer and transducer, shows inductive impedance at the mechanical resonance frequency of the transducer, a serieswound suitable capacitor can achieve better performance than the traditional matching inductorbased scheme. Otherwise, a comportable serieswound inductor is needed. As a result of the above treatment, the state of conjugated matching between the supply amplifier and its load is reached. A series of texts demonstrate that, in comparison with the traditional secondary serial inductor matching scheme, the new scheme takes advantage in term of the matching precision and power transmission efficiency.

Key words: engineering physics, primary series matching, air core transformer model, piezoelectric ultrasonic transducer, output transformer, conjugated matching