UAV Market Trends and Power System Seminar 2025 Taipei, Taiwan
Power modules enable top performance and innovation for today’s advanced UAVs
Case study: Tethered Underwater ROV
DC-DC transformer facilitates implementation of longer tether
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
The extremely small, low weight BCM® Bus Converter, acting as a DC-DC transformer, converted the high voltage from the tether down to the 48V distribution architecture on board the ROV. It provided a simple, easy to implement, off-the-shelf solution.
Key benefits
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.
Isolated fixed-ratio
Input: 800 – 48V
Output: 2.4 – 55.0V
Current: Up to 150A
Efficiency: Up to 98%
As small as 22.0 x 16.5 x 6.7mm
Non-isolated regulated
Inputs: 12V (8 – 18V), 24V (8 – 42V), 48V (30 – 60V)
Output: 2.2 – 16V
Current: Up to 22A
Peak efficiency: Up to 98%
As small as 10.0 x 10.0 x 2.56mm
Resources
Resources for the design engineer
High-efficiency, high-density modules free up space for advanced communications and extend range
High-efficiency class of UAV depend on solar power to meet its long flight time requirements
High-density, high-power modules enable lighter, safer, lower cost tether cables to extend missions
This class of unmanned vehicle is powered and controlled via a tether from a ground-based power source assisting in extended missions
DCM DC-DC converters double the internal bus power and help keep the aircraft as light as possible
High-altitude long-endurance (HALE) UAVs are essentially flying satellites, designed to operate at extremely high altitudes for extended periods