Case study: Tethered Underwater ROV

DC-DC transformer facilitates implementation of longer tether

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Customer’s challenge

Allowing an underwater ROV to perform remote inspection activities at greater depths required the tether from the ship-based power source be extended. Distributing the original design’s low voltage over the longer tether was not practical due to voltage drops. Moving to a high-voltage 700V low-loss tether, however, required conversion to a lower SELV voltage onboard the ROV. This typically requires a custom converter that takes up space and adds weight, not feasible in an ROV that needs to be able to carry increased payloads. The key goals were:

Extending the tether, required for deep or remote inspection, without loss of performance
Avoid the high cost of a custom discrete power solution while saving space and weight
Retain clear transmission of data via the tether for onboard sensors

The Vicor solution

Vicor high-efficiency and high-performance power modules enable inspection UAVs to minimize size and weight to maximize the sensor payload required to perform the actual inspection. With enough power and high efficiency, they allow for an agile UAV with increased flight time, even in harsh environments.

Key benefits

High-voltage tether reduced the supply current, and thus losses for a given cross-section of copper conductor, allowing for a thinner, longer tether

Reduced footprint of 1.5kW solution to just 41cm2

Low noise conversion topology prevented interference with communications over the tether

Power delivery network

The power delivery network: The BCM isolated and stepped-down the high tether voltage input to a nominal 48V, a factor of 1/16. Output was 1.5kW in a footprint of just 39cm². The BCM provided enough power to drive 48V motors, thrusters and control electronics. Its high efficiency simplified the cooling within the vehicle. ZVS Buck regulators converted the 48V SELV distribution to 5V and 3.3V to power downstream points-of-load. To analyze this power chain, go to the Vicor Whiteboard online tool.

Learn more about the modular approach to power