Hi Gareth,
Some info about HMS Duncan. Well, without disclosing information which, for obvious reason, is restricted:
The concept is called AES (All Electric Ship) and was first introduced to the Royal Navy in ships like Fleet Tankers and the LPD Class (Landing plattform Dock HMS Albion and HMS Bullwark)
Of course in a "front-line" ship like Type 45 HMS Duncan it gets much more difficult - much higher power, shock requirements etc.
Basically 2 Rolls-Royce Gas Turbines are driven high-speed generators (the ship is a power plant) and the power is ditributed through a high voltage grid feeding huge slow speed Advanced Induction Motors.
My company was designing special components for the generators and motors and I am responsible for the sales and engineering team.
The same propulsion concept (larger though) is used for the newAircraft Carriers. Also with our components.
Let me know if you have questions
Take care
Norbert