Research and Design for the Power Hierarchy of a 160-Element Linear Towable Ocean Acoustic Coherent Hydrophone Array

An efficient, organized and pressure tolerant electronic design is required to carry power to a 192-meter-long ocean acoustic coherent hydrophone array developed at Northeastern University. This oil filled linear towable large aperture hydrophone array is densely populated. The array consists of eight sub-sections, of which five are acoustic containing 160 hydrophone elements, two are non-acoustic sections, containing depth and heading sensors, and one vibration isolation module (VIM). This underwater acoustic array receives its power from a 5000W Power Supply housed on a research vessel (RV) or ship. The 300VDC output generated from the power supply travels through a 600-meter-long tow cable before it reaches the in-house designed main power board in the hydrophone array, bucking the voltage down to three independent 48V power rails. Multiple voltage rails were used to reduce current draw and voltage drop seen down the long-twisted pair of 16-gauge wires, feeding four other in-house designed power boards; 24V, 12V, 12V/-12V and 5V. During in-air operational testing while under high power producing conditions, thermal run-off was seen on the main power board. Although this is not critical for this application, precautions were made to allow for seamless testing. A commercial off-the-shelf (COTS) heat sink was cut and thermally epoxied around the main power integrated circuit (IC). Combining this with oil, which acts as a heat sink and the length of the array, an effective heat reservoir was produced. Detailed research and design were instrumental in the component selection, schematic and layout phases of this design to create a reliable, resilient, and cost-effective system. Future improvements and paths forward will also be discussed to improve reliability, energy efficiency and robustness.