Upping the Amps

After making a splash on the market with its pinless, wetmate connector Maelstrom in 2013, Elaine Maslin examines how Bergen’s WiSub is upping the game.

The Torden pinless wet mate connector.

Small, Bergen-based, tech-focused firm WiSub stirred up a storm with its pinless wetmate connectors in 2013, enabling pinless data and power transfer subsea, at up to 100Mbps and 24 Watt, using high-speed, high-frequency microwave electronics (used for through-air communications systems, and low frequency inductive power transfer).

Now, following customer specifications for higher power capacity, the firm has upped the ante and released Torden (“thunder” in Norwegian), a new design pinless wetmate connector able to transfer 1000 W of power across a 0-10mm seawater gap, significantly expanding the envelope of what these wetmate pinless connectors can do.

Key to the technology has been creating stable power regulation, without the use of batteries, which the firm describes as a significant achievement in the oil-filled pressured balanced system product’s development. The firm is also set to release a pinless wetmate fiber optic connection, which could be a first for the industry.

The benefit of WiSub’s pinless connector is that it is not limited to cycle times and misalignment issues, and has higher performance than low frequency RF, inductive or acoustic technologies, WiSub says.

Olof Nilsson, project manager, WiSub

The increased power rating will give operators the freedom to increase monitoring and controls on subsea BOPs and could be used to power-up resident AUVs. “AUVs could benefit from having a battery charger or underwater docking station, on which they could use our connector,” says Olof Nilsson, project manager, WiSub.

But, to create Torden, it wasn’t possible to just scale-up Maelstom, Nilsson says. A new design was needed with both the power and data transfer designed together to best satisfy the new specification.

“Dealing with lower powers in pinless connectors means dealing with lower amperages (current) and thus lower-rated components, less adverse consequences to imperfect design, and simpler management of power transfer,” says WiSub CEO Mark Bokenfohr. “In our high-power connector (Torden), we transfer a kilowatt at 24v, where a 1% change in efficiency or ‘imperfect transfer’ can increase heat significantly. Transferring power to the wrong place can also have more dire consequences, such as heating something metal inadvertently – our pinless power transfer designs always have certainty that we are only transferring power from our transmitter to our receiver, and not to something else.

“Not using a battery nor limiting input power to AC volts was also a challenge, especially around power storage for stable power delivery. Our decision to transfer 24v DC in/out, due to customer specification, has also led to high current challenges. Others choose to take in 110v AC to their transmitter, allowing lower amperages (9 Amps) and thus easier circuitry and components. 24v DC, in comparison, results in 42 Amps, providing some interesting challenges around physics.”

WiSub’s Maelstrom connector. Photos from WiSub/Kolbrun Retorikk.

WiSub’s next big step, the pinless fiber optic communications follows a three-year research program. Fiber could run alongside Ethernet to enable flexibility, depending on what is at the other end of the connector, i.e. if you have a video camera far away from connector, Ethernet will only take you about 100m, due to the copper cable length limitations for Ethernet, Nilsson says.

Traditional fiber wet mate connection systems align one optical fiber with another optical fiber through a very complex pressure-balanced, oil-filled assembly that only allows limited wet-mate cycles. In WiSub’s connector, the signal travels via light through the optical fiber, or via copper cable, is then converted to an electrical signal, which is passed through the water gap via an MW link, before being converted back to light over fiber optic or to copper on the other side.

Because of its media-independent design, the connector allows the user to interface their systems to either copper or fiber, or both, Bokenfohr says.

WiSub’s product is a full-duplex 100 Mbps fiber + copper connector, where you can use either copper or fiber, or you can connect both lines for redundancy, with data rates through either line configurable by the operator.

To gear up for expansion, the firm recently moved to new fjordside offices in Eidsvag, just north of Bergen. Whilst they’re a small company, they lean on the subsea of the subsea cluster, outsourcing manufacturing, performing prototype qualification and testing with project partners. Most development, assembly, and quality control remains in house.