Sprayable Polysulfide Elastomeric Development

The development of compact, light-weight power-electronics for driving underwater acoustic transducers has been the subject of research over the past 30 or more years. Improvements have occurred in parallel with advances in power electronic switchingdevices, most notably, the development of the silicon MOSFET, essential for the high-efficiency switching-amplifier technology widely used today. We are on the threshold of another advance in power-electronics, the advent of silicon-carbide semiconductortechnology, which offers great improvement in semiconductor operating temperature and voltage ranges. Its higher temperature capability will enable greater packaging density and its higher voltage capability will provide a closer matching of the switchingdevice voltage rating with the voltage requirements of typical transducers, leading to the possibility of size reduction in impedance matching components. We propose to research the application of silicon carbide technology to an example hull-mountedsonar system, the AN/SQS-53C (part of SQQ-89 system), and determine its beneficial impact on transducer, power-amplifier and overall system design.As a minimum, we expect an improvement in power-amplifier density due to the higher temperature capability ofsilicon carbide, a benefit particularly significant for pulsed-power applications such as the 53C, with its high peak-to-average power ratio. A major benefit is the possibility of eliminating the power-amplifier output transformer. This transformerweighs an estimated 3 pounds and occupies about one-third of the volume of the power amplifier. For a system of about 600 amplifiers, the weight savings would be on the order of 1800 pounds. We expect the high voltage, high frequency capability ofsilicon-carbide switching devices will be adequate for driving the transducer element directly, eliminating the need for the output transformer. If the transformer can be eliminated, a third benefit is the possibility of integrating the power amplifierwith the transducer, offering the opportunity for another significant reduction in overall system size and weight.