The first machines built as part of the collaboration can fly two hours on a single charge and have already transported masks and emergency supplies between US Virgin Islands. The drones feature a number of power components by Vicor.
A DMI drone delivering emergency medical supplies to the Virgin Islands. Image used courtesy of DMI.
Partnering on Power Pack Performance Optimization
The drones built as part of the collaboration between Vicor and DMI fit into the wider research goal of developing mobile robots featuring extended range and load capacity.
To achieve this objective, the companies needed to develop a hydrogen fuel cell for mobile devices that was innovative from materials science to full system-level design optimization.
In other words, they had to develop light-weight, miniaturized components capable of increased efficiency, and of high energy output and durability. The result was drones with reduced stack weight, a powertrain with high power density, and a simplified design of the overall power pack, including peripheral components.
Essential in the design of these machines was the architecture and implementation of the systems power delivery network (PDN). The DP30 power pack behind the new drones features two main powertrains supplying power to the devices’ rotors and to the controller for the two stacks.
Image used courtesy of Vicor.
Powered by Vicor’s High-end Components
To ensure PDN high efficiency and high energy density, DMI integrated into the new drones Vicor PRM buck-boost regulators and a ZVS buck regulator.
The buck-boost regulators support the up to 74V open-circuit voltage (OCV) of the hydrogen fuel cell stack and perform stable voltage regulation to 48V.
Additionally, two PRM buck-boost regulators (PRM48AF480T400A00) are also configured in parallel in the drone’s rotor-side PDN to supply the 12A required.
The PDN for the digital controller board in the stack, on the other hand, uses a lower-power PRM (PRM48AH480T200A00) paired with a 48V-to-12V ZVS buck regulator (PI3546-00-LGIZ).
Energy density comparison between hydrogen fuel cell and lithium power. Image used courtesy of Vicor.
Looking forward, DMI plans to leverage Vicor’s modular approach to diversify product lines by power capacity, introducing other options to the 2.6kW DP30 power pack currently in production, and corresponding drones suitable for each power pack.
These would range from the 1.5kW hydrogen fuel cell power pack, which the company confirmed will be released next year, to a 10kW one.
Designed for Humanitarian and Commercial Missions
Beyond transporting emergency supplies between US Virgin Islands, the new drones have also already delivered medical AEDs to the top of Mt. Hallasan, the tallest mountain in South Korea on Jeju Island.
Furthermore, DMI clarified how these extended-range drones are particularly suited for commercial applications where longer flight times are a necessity.
For instance, the machines have been deployed to Monitor large solar farms, like the one in Solasido, Haenam. For context, when performing the same flight using a battery-powered drone, more than six battery replacements were reportedly needed.
A DMI drone inspecting a solar farm. Image used courtesy of DMI.
Through the partnership with Vicor and its hydrogen fuel cells, DMI is now directing its efforts toward solving engineering problems arising from the expansion of power capacity.
These include stack structure changes, powertrain, and peripheral components, and heat dissipation method.
With the release of the new drones, the companies are one step closer to increased durability and stability as well as improved miniaturization and lightening of fuel cells with high energy density.