Broad Band Impedance Matching Transformer Design Consideration for High Power Electro-acoustic Transducer

摘要

Matching the output impedance of SONAR system’s transmitter with the input impedance of high power electro-acoustic transducer is important to improve its transmitting efficiency by maximizing the transfer of power. In this work, an attempt has been made to match the output impedance of power amplifier (4 )with the input impedance of high power (2000 watts) and high impedance (1387 with phase angle of 85° at its resonant frequency i.e 2.5 KHz) Piezoelectric material based ElectroacousticTransducer, by realizing a Broadband Matching Transformer. Designing of the matching transformer is undertaken using Lump Circuit Modeling and NetworkTheorem. Matching Transformer has been designed to meet the required specification by sequentially following measurement of transducer’s impedance as a function of frequency using Impedance Analyzer and computation of its equivalent circuit element's values based on measured parameters of the transducer. Matching transformer was developed using composite Iron alloy based C-type and Toroid-type Cores. Impedance and phase angle of the tuned transducer were found to be equal to 3.6 and phase angle of 14.5°, respectively. It is pertinent to mention that no significant influence of the core type variation was observed on results. Impedance results of the tuned transducer were also taken as a function of frequency to evaluate the broadband performance of the Matching Transformer. Source Pressure Level ofthe resonating transducer with matching transformer was observed to increase from 137 to 164 dB/ˇPa @ 1m when gain of the amplifier was set on 6dB. Results of the work are promising and expected to contribute a lot in the development of Underwater Surveillance Systems in future.